I
Vol. 19, N o. 6 J U N E 1, 1927
The Privy Council Report
T 'H E Committee of the Privy Council for Scientific and 1 Industrial Research of G reat B ritain has recently issued its eleventh report, which contains much food for thought.
We have examined w ith interest th e summ aries of the work carried on by some tw enty-six trade associations, the for
mation of which has been encouraged by th e British Govern
ment for the prosecution of research. Of these, twenty-two have been in existence for more th a n five years, two have terminated their existence, while a th ird has tem porarily sus
pended operations. Some of th e activities of the British Coun
cil could be duplicated in our own country w ith much advan
tage; for example, a “ survey of th e sta te of scientific and industrial research in th e country in order to afford an opinion as to how far its developm ent could be further assisted.”
' The Departm ent of Scientific and Industrial Research finds some of the greatest opportunities, and indeed the larg
est demand a t present, for trained men to be in the border
lands between chem istry and agriculture, chem istry and botany, chemistry and physics, and other such subjects.
Reference is also made to th e proper relationships between government and industry in the prosecution of research.
Here we find it stated th a t “ the limits (speaking of money grants) must be dictated not only by th e distinction of the worker and the nature of the work b u t also b y the unde
sirability of using public funds to provide assistance which would more properly come from other sources.” And while the Council, which has been given some large funds for-dis- bursement. in support of scientific work, has stood ready to assist researches in new fields of knowledge, particularly those which appear to be of potential benefit to industry, it clearly believes th a t the G overnm ent’s function is to en
courage research in neglected fields, occasionally to tak e the lead in these new researches, b u t always to be careful th a t the Government does n o t undertake research which can better be done by the industries themselves. “ The main problem with which we are faced is how to encourage and assist the movement for industrial research w ithout taking over functions which are best carried out by industry itself.***
A large portion of the work of a governm ent research depart
ment must necessarily be directed tow ard helping industry to help itself.” A t the same tim e it m ust be recognized th a t there are certain types of research problems of such wide in
terest or of such im portance to the welfare of th e sta te th a t they cannot be left wholly to private initiative.
Again we find th e Council clear in the opinion th a t pure and applied research cannot be prom oted as it should be until public opinion is fully aroused to its necessity, an argu
ment th at has been used with justification throughout the development of the A. C. S. News Service. Another point of mutual interest is th e insistence th a t industry build up a reserve of scientific knowledge in the creation of which the expenditure of stockholders’ money is am ply justified, and look upon industrial research “ not as a cure for b u t as a prevention of bankruptcy.”
One other reference, and perhaps one of the m ost impor
tant, is to the rock upon which several programs of trade association research have grounded—namely, the appli
cation to the industry of the results of industrial research.
I t is not difficult, as the report points out, to prepare reports of research results, b u t to m ake sure th a t the members of the association apply these results and thus directly benefit from the work they support is quite another m atter. As soon as the time comes when they think th a t the return is n ot adequate for their expenditure, there is either a curtail
m ent of funds or internal dissension th a t m ay even cause the suspension of association work. The remedy would seem to be the creation of an educational section and of a strong utilization section in any trade association research organi
zation and perhaps even in the scientific groups of our larger industries.
After all, science in industry is a com paratively recent innovation. .More thought is being given to it than a t any other period, and we m ay confidently expect even th e m ajor problems to be reduced to their com ponent parts, which will be solved one by one.
Table d’Hote
A M EN U offering so wide a choice as to meet thediversi- fied tastes of chemists is in preparation for the In sti
tu te of Chem istry of the A m e r i c a n C h e m i c a l S o c i e t y .
Prelim inary announcem ents have been m ade and book
lets, filled w ith detail, are available to those who will write for them. The In stitu te is not to be confused with any other chemical activity in this country. I t is unique: I t is de
signed for a special purpose, and we predict th a t those ■ who procrastinate m ay find themselves deprived of one of the best opportunities which has been afforded American chem
ists.
If you are intent upon working every m inute, the program of the In stitu te will afford opportunity for the utilization of your energy. T he News Editions of M ay 10 and 20 indi
cated a num ber of courses which m ay be attended a t will by those who desire no college credit for their sum m er’s work. In this way a variety of topics, presented by spe
cialists, can be heard. The morning until 11 o’clock can be thus occupied, while each day a t th a t hour a general con
ference, for which some of the topics have been announced, will take place. Here recognized authorities will sum up for you th e present sta tu s of th e science in a particular topic, followed by general discussion. A t the close of th e con
ference interested groups will undoubtedly continue the discussion in the institute dining halls. T hereafter you m ay gather under the trees, a t golf, or atten d other courses.
The laboratories will be open and every chance given for work. In the early evening scientific motion pictures and later additional lectures and similar events for instruction or entertainm ent will be offered. No doubt in m any cases groups will continue discussions “and so on far into th e night.”
G58 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 19, No. 6 Arc you less am bitious? T hen look over the program
and take w hat suits you, ju st as you choose from any table d ’hote menu. There are the courses—m any of them —the daily conferences, the contacts w ith those who share your interests, the motion pictures, the evening lectures. Cer
tainly a wide variety!
Perhaps you are not in the mood for anything bordering on work. In th a t case not only can you do as you please, scientifically speaking, b u t you will find a t S tate College th e real recreation which mountains, stream s, highways, and sports afford, w ith the opportunity always a t hand to get ju st th a t degree of m ental exercise you m ay desire, especially after a few days of simon-pure loafing have passed.
And all this a t a cost which those who have seen the sched
ule of fees and living expenses agree is most reasonable!
Announcements relative to speakers, lecturers, and teach
ers clearly indicate the desirability of being a t S tate College for a t least a p art of July. You are urged to reach a de
cision and to obtain full details from the several issues of the News Edition or direct from A. W. Kenney, In stitu te of Chem istry of the Am e r i c a n Ch e m i c a l So c i e t y, S tate Col
lege, Pa. This is an event of the So c i e t y so im portant to you as an individual th a t you cannot afford to disregard it in making your summ er plans.
Department Chairmen
T T IS inevitable th a t the growth of appreciation of science on the p a rt of industrial organizations should decimate the ranks of college and university professors, not leaving untouched departm ent heads and chairmen. Much has been said regarding this policy, believed by m any to be shortsighted, b u t while it should bo clear th a t a shortage m ay soon develop in the supply of adequately trained scien
tific men if the machinery for their developm ent becomes crippled, industry generally is inclined to let the future care for itself and to obtain for the direction of its own research men who have dem onstrated leadership in the scientific field.
We sometimes think the freedom from some types of executive work is a p a rt of th e appeal which the industrial laboratory m akes to the academic man, though a depart
m ent head doubtless looks upon it as a different sort of adm inistrative job, the details of which are more attractive.
Certainly the farsighted industries offer a freedom for scien
tific work quite as much unham pered as th a t which the academic laboratory affords. Our schools are, therefore, faced w ith a new com petition in which changing conditions have lost to them some of their former advantages.
Our colleges and universities should adopt a new policy if they are to a ttr a c t and hold the professors necessary to train in America men satisfactory for the research laboratories of academic and industrial life. We see frequent examples of one m ajor disadvantage in present policies. This is the prom otion of a successful teacher or director of research to an executive position for which he m ay not be tem pera
m entally fit and which really does not a ttra c t him, so far as its duties and opportunities are concerned. M any a good scientist has been spoiled to m ake a poor executive.
T he obvious way out of this difficulty is to recognize a t once th a t there is a place in any great development for an executive head, call him w hat you will, who does not nec
essarily have to be the greatest m an in his specialty. Of course he m ust have a broad sym pathy w ith the science and some actual experience in it, b u t if he is the right sort of m an he will not hesitate to secure for the departm ent the best available teachers and directors of research, even if all of them rank far above him in scholastic standing and
perhaps in m onetary rem uneration as well. Such an execu
tive would work for th e advancem ent of these men according to their results. He would not disturb them in the work at their choice, b u t would see th a t everything possible was done to m ake the productive men more productive and to elimi
nate quickly the non-producers. Such an executive would also relieve those successful in teaching research of multi
tudinous com m ittee meetings, the details concerning pur
chases, and a host of other activities which now serve merely to divert them from their main purpose. Such an arrange
m ent m ight appear as an addition to overhead, but it is the kind of overhead th a t becomes a good investment through releasing productive men from non-productive activities.
Another factor w orthy of serious consideration is the precedent th a t has become established of considering members of the faculty as appointed for life after they have been prom oted to a given rank, w ithout regard to their produc
tiv ity or their effort to rem ain abreast of the times. Pro
motion is slow b u t in m ost institutions it is certain, granted only good behavior and reasonable activity, and some men are passed along from grade to grade until they have a life position from which they cannot be budged except for grave misdemeanors. In consequence, we find here and there a faculty so loaded down w ith deadwood that its progress can be measured only in term s of geologic time, and science suffers as a result.
Several suggestions have been m ade for the correction of this situation. One is the adoption of the foreign plan, whereby professors are paid a small salary by the institution, deriving the rem ainder of their income from fees paid by their students who are given considerable leeway in choosing their courses. I t is said th a t this plan is satisfactory to the success
ful leader of students, and soon indicates to the unsuccessful and unpopular m an the desirability of seeking another location. No doubt there arc other ways out, but it is high tim e th a t some practical solution should be developed and p u t into operation.
All th a t has been w ritten and said concerning the need for the support of pure science research can be heartily endorsed, b u t unless great care is tak en we shall find our
selves w ithout an adequate scientific staff when the research funds become available.
Surprises in September
T T HAS been a m a tte r of general regret th a t recent expo- sitions of the chemical industries, while quite complete as regards equipment, have n o t displayed th e actual products of the chemical industry, and particularly of chemicals, to the extent which all would have desired. We are glad to note th a t chemical products are to have a prominent place in th e Eleventh Exposition, which opens September 20. The present list of exhibitors includes nearlyr fifty—a number are of foreign origin—which can be classified as chemical.
The nature of these exhibits cannot be disclosed, but sur
prises are certain and it is hoped th a t m any of them will be presented by the American chemical manufacturers.
Almost a new generation has m ade its appearance in the chemical industry since chemicals and chemical c o m p o u n d s were featured a t th e exposition. M anufacturers who have felt th a t all potential customers had been reached in former shows m ust now consider this new audience, which has come from the educational institutions and found its place in in
dustry, as purchasers and users of equipm ent and materials.
The coincidence of a large num ber of new exhibits with visits b y m any who have b u t recently entered the chemical industry should m ake the Eleventh Exposition a long remembered event.
June, 1927 I N D U S T R I A L A N D E N G I N E E R IN G C H E M I S T R Y 059
Anniversaries
T
HREE notable silver anniversaries have already come to us in 1927. We congratulate the American Electrochemical Society, the American Society for Testing M ate
rials, and our contemporary, Chemical and Metallurgical E n gineering, on rounding out a q uarter of a century of very useful service. The societies celebrate with special meetings, while Chemical and Metallurgical Engineering has already issued its special anniversary num ber. To some, including our friends abroad, twenty-five years seems altogether too brief a time to deserve special notice b u t the records of the p ast qiiarter-century show th a t in a country so young as ours there has been much accomplished th a t is an inspiration for future growth and stim ulation for continued development.
Lower Cost Arsenate
rA N E interesting result of investigations m ade by the
^ Chemical W arfare Service looking to th e b etter con
trol of the cotton boll weevil, the prelim inary report of which we present in this issue, has been the development of a proc
ess which promises calcium arsenate in acceptable physical form at lower costs. T he extent to which the cotton farm er can employ calcium arsenate is determ ined by the price of cotton and its relation to the price of this chemical compound.
While both prices fluctuate between wide limits, it is ob
vious that a uniformly low-priced arsenate would encourage its more frequent and extensive use, thereby affording a more complete control of the boll weevil and consequent lower production costs for the cotton farmer. The per
fection of the process is another indication of the peacetime utility of the Service. T he careful consideration of its work in this field is recommended to all interested in th e insec
ticide and fungicide question.
Youth N o Handicap
TMIOUSANDS of young men and women will soon leave our colleges and universities to find their places in our economic structure. Some m ay feel bewildered when they consider what has been accomplished and have impressed upon them the seriousness of living and pursuing their work without the protection of stu d en t days. Few of us realize how much good work has been done by young men. I t is to emphasize this th a t we pass along a note taken from The Oil Can:
Martin; Luther was tw enty-nine when lie wrote the manifesto that led to the Reformation.
John Calvin was tw enty-six when he wrote "The Institutes of Theology.”
Patrick Henry w as tw enty-seven when he made his speech against the Stamp Act.
Thomas Jefferson was thirty-three when he drafted the D ec
laration of Independence.
Alexander H am ilton w as aide-de-cam p of W ashington at twenty, and a t thirty-tw o first Secretary of the Treasury.
Napoleon was tw enty-seven when he was appointed to the command of the Army of Ita ly , and thirty-five w hen he crowned himself Emperor of the French.
Alexander had conquered the known world and was dead at thirty.
Charlemagne w as m aster of France and Germany a t thirty.
James Fox was Lord of the A dm iralty and a thorn in the side George III at tw enty-one.
W illiam P itt became Chancellor of the Exchequer a t tw enty- three, and Prime M inister a t twenty-four.
Charles Dickens was twenty-four when he began "Pickwick Papers” and twenty-five when he wrote “ Oliver T w ist.”
Poe was doing some of his best work a t tw enty-five.
Balzac wrote seventy-nine novels between the ages of thirty and forty-three.
James Bryce had written "The H oly R om an Em pire” at twenty-six.
Benjamin Franklin had w ritten "Poor R ichard’s Alm anac” at the same age.
D avid Hum e a t tw enty-six had shocked all Christendom with his highly heretical "Treatise on H um an N atu re.”
Ruskin wrote "M odern Painters” a t twenty-four.
Stevenson had com pleted “ Treasure Island” a t thirty-three.
K eats, Shelley, and Byron were dead a t twenty-five, thirty, and thirty-six, respectively.
Sheridan wrote "The School for Scandal” a t tw enty-seven.
Shakespeare had com pleted ten of his greatest plays a t thirty- two.
N ew ton formulated the law of gravitation at twenty-four.
M cCormick and W estinghouse were tw enty-three when they invented the reaper and airbrake.
M ichelangelo did his statu e of D avid a t tw enty-six.
T he list does not pretend to be complete. Y ou can add your own heroes and heroines. Also, if you care to tak e the time, you will find an equally imposing list of men who did their best work after forty. The moral is, “ There is no dead line on achievement, b u t it pays to sta rt young.”
In the American Manner
Y~YUR contemporary, Chemistry and Industry, the official publication of th e Society of Chemical Industry, has paid us the compliment of commenting editorially upon the In stitu te of Chem istry of the Am e r i c a n Ch e m i c a l So c i e t y, which holds its initial session a t S tate College, Pa., beginning Ju ly 5. How we wish our British cousins in considerable numbers m ight find it possible to join us a t S tate College!
T hey would see a dem onstration of how American chemists utilize such occasions to further projects sim ilar to those which engage their attention a t home. If, a t times, progress has seemed slow we believe one cause to be the com paratively limited and often strictly selective acquaintance of th e aver
age British chemist with his fellows.
N o t so long ago it was our privilege and pleasure to journey to the Pacific and return w ith a group of em inent British scientists, including some th irty chemists. We secured a list and set out to .learn more of the activities and affiliations of these visitors. We began our inquiry by approaching a few of those chemists whom we had previously m et. Imagine our astonishm ent upon finding th a t these chemists from overseas not only did not know each other b u t saw no par
ticular reason why they should. These men had had the enterprise to journey from G reat B ritain; they had come on the same vessel; they had spent nearly two weeks together in C anada and were now setting out on a round trip journey across th e American continent; and still they were unac
quainted. I t was a new experience to see two fellow scien
tists dining a t the same small table in the diner of th e special train quite in silence because they had never been introduced.
And there were similar occasions quite beyond th e under
standing of the few Americans on the trip, to whom we believe some credit is due for the change in a ttitu d e of m any in
dividuals before the end of the journey. In consequence they not only took home some new acquaintances b u t left m any lifelong friends in America.
Now if we could have a few of our British friends a t S tate College, we would show them th a t a holiday and the science of chemistry can be admixed w ithout detrim ent to either.
T hey would find in the relaxation and informal discussions a t the In stitu te of Chem istry m any opportunities to ripen acquaintanceship into friendship and to further th a t type of wholesome cooperation and delightfully informal contacts which, in a very large degree, have been responsible for such progress as has been made, not only by the Am e r i c a n Ch e m i c a l So c i e t y, b u t by th e American chemical industry and, indeed, by chem istry itself.
If adopted as a British policy, who can tell b u t th a t Chem
istry House and a united association of all British chemists m ight n o t autom atically follow?
600 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 19, No. C
Progress of E lectrom etric C o n tro l M ethods in In d u stry 1
B y H en ry C. P ark er
Re s e a r c h De p a r t m e n t, Tu e Le e d s & No r t i i r u p Co., Ph i l a d e l p h i a, Pa.
D
u r i n g th e past few years the progress in th e use of electrom etric control in industry has been quite m arked. How
ever, th e advantages of these m ethods are only ju st begin
ning to be appreciated in the c o m m e r c ia l w o r ld . The future progress in the field appears to be limited only by
the complexity of some of th e problems and by th e not infrequent necessity for specifically adapting th e control principles to individual cases. Although this engineering development work increases th e cost of these installations, the advantages gained by obtaining a true record of con
centration, as well as a more accurate control, have been proved to far outweigh the initial expense in a t least the m ajority of cases where electrom etric m ethods have been tried.
R e c e n t I m p r o v e m e n ts in A p p a r a tu s
Ce l l s a n d El e c t r o d e s—T he recent progress in elec- trom etric control has been given considerable im petus by th e development of im proved electrodes and cells. One
of th e first satisfactory types of i n d u s t r i a l c o n d u c t i v i t y cell is shown in F i g u r e 1.
The e l e c t r o d e s a r e m a d e of b r a s s rods capped with gold and molded w ith Bakclitc into a b r a s s t u b e . The whole m ay be in
serted through a gate valve, m aking a con
veniently removable
F ig u r e 1— R e m o v a b le -T y p e C o n d u c t i v i t y and sturdy cell, Suit
able for n e u t r a l o r slightly acid solutions. The Bakelite makes tig h t joints w ith the brass rods and tube, which are capable of w ith
standing 300 pounds hydrostatic pressure w ithout the use of any packing glands or cements. T he gold caps are platinized and then sand-blasted to drive the platinum back into th e gold, forming a surface which is such th a t polariza
tion is negligible and which, under norm al conditions of op
eration, requires no subsequent platinizing. This new type of surface has relieved th e operator of th e only remaining m anipulation which is reminiscent of th e research laboratory.
A t present these- cells are being successfully used for meas
uring surface condenser leakage in a num ber of power plants in various p arts of the country.
I t has not been found possible to eliminate the use of glass in the construction of cells for some types of service. In Figure 2 are shown two of th e m ost convenient glass cells.
T he cell to the left is used as a standard for autom atic tern-
1 R eceived M arch 9, 1927. P resen ted before th e D ivision of In d u stria l a n d Engineering C h em istry a t th e 73rd M eeting of the A m erican C hem ical Society, R ichm ond, V a.. A pril 11 to 16, 1927.
perature com pensation,*
while th a t to the right is the test cell. These cells are giv
in g s a t i s f a c t i o n in several types of service. When in
s t a l l e d they are generally protected by a metallic or composition case.
M ost of the improvements in H-ion measuring apparatus have been described previ
ously.3 In Figure 3, however, is shown for the first time a flow- type quinhydrone electrode which has been giving satisfac
tion in several types of service for over a year. The quin
hydrone is p u t into cloth bags which are placed in the adapter a t th e base of th e flow channel. The te st solution flows past these bags of quinhydrone, becoming sufficiently saturated to supply' th e gold electrode. This apparatus can be used advantageously to obtain a record or a control through a pH range of about 3 to 7.5. In m ost solutions correct results will be given to a pH of 8.5, b u t th e increased solubility of th e quinhydrone makes its operation rath er expensive. The rate of solution m ay be governed to some extent by using cloth bags of heavier m aterial. T his m ethod of introducing th e quinhydrone is much more convenient than regulating th e ra te of dropping of a saturated solution.
Co n d u c t i v i t y Re c o r d e r—N o t all of th e recent im provements have consisted in the develop
m ent of cells and electrodes. In Figure 4 is shown a connection diagram for a conductivity re
corder which has several advan
tages. By moving the main slide wire the resistance of onlyr a single bridge arm is altered, while in the conventional bridge one arm is in
creased while the other is dimin
ished. A bridge c o n n e c t e d a s shown in the figure gives a scale which is linear in term s of con
ductance units. Since, in the large m ajority of solutions and over a short range of concentra
tion, the conductance is propor
tional to th e concentration, it is obvious th a t we can use a linear scale in c o n n e c t i o n w ith t h i s W heatstone bridge which reads per cent concentration in term s of a s t a n d a r d s o l u t i o n which is
placed in the cell to th e left in F ig u r e 2—T e m p e ra tu rc -
Figure 2. This scale is shown in C o m p ' ^ t ' s t CeTi
Figure 5, where the recorder reads
from 60 to 120 per cent. This scale means th a t if a 3 per cent solution is placed in the standard cell, and if the
recorder reading is 100 per cent, the te st has a c o n c e n tr a tio n 3 B ishop, U. S. P a te n t 933,015 (A ugust 31, 1009).
1 P a rk e r an d D a u n erth , T ills Jo u r n a i., 17, 637 (1923); Parker, IbU->
737 (1925).
A r ev iew is g iv e n o f th e p r e s e n t s t a t u s o f e le c tr o m e tr ic c o n tr o l in in d u s t r y . I n s t a lla t io n s in v a r io u s in d u s t r ie s are d e sc r ib ed , in c lu d in g m e r c e r iz in g , s u lf u r ic a c id m a n u fa c tu r e , w a s te d is p o s a l, s u g a r m a n u f a c t u r e , a n d in t h e w a te rw o rk s a n d p o w er p la n t field s. S ev e ra l o f t h e d iffic u ltie s e n c o u n te r e d in n e w a p p lic a t io n s a r e m e n tio n e d a n d t h e v a r io u s a d v a n ta g e s g a in e d b y e le c tr o - m e tr ic c o n tr o l a r e d is c u s s e d . T h e p r o g r ess m a d e w it h in t h e la s t fe w y e a r s h a s b e e n m a in ly d u e to i m p r o v e m e n ts in t h e r e q u is it e a p p a r a tu s .
June, 1927 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 661 of 3 per cent. If the recorder reading is 90 per cent, the
concentration of the te st solution is 90 per cent of the stan d ard or 2.7 per cent, etc.
The dial m arked A , Figure 5, is connected w ith the slide wire, A, in Figure 4. This slide wire gives a convenient means for adjusting th e bridge for a difference in th e con
stants of the two cells. I t will be noted th a t th e te st cell (to the right in Figure 2) has a constant which is adjustable by raising or lowering the center tube. This adjustm ent is
m ade while both cells a r e im m e r s e d in and m e a s u r i n g t h e s a m e standard solution. The dial A is set a t zero, the recorder is stopped a t 100 per cent, and the center tube is then a d j u s t e d until the galvanom eter is n e a r ly balanced. Fine adjustm ent m ay be made by turning the dialyl. If the te st solution is being controlled a t a concen
tration reading 100 per cent, and if it is desired to change th e controlled concentration by 10 per cent, for example, this change m ay be m ade by t u r n i n g t h e d i a l y i
t h r o u g h ten divisions.
In this case th e concen
tration of th e te st solu
tion is found b y adding or subtracting th e read
ing of dial yi from th a t i n d i c a t e d on t h e re
c o r d e r . Changing the
■1 is easier than by tu rn -
Figure 3— F lo w - T y p e Q u i n h y d r o n e E le c tro d e
control point by shifting the dial ing the control disk.
A similar diagram of connections forms the basis of a new portable conductivity bridge which reads in either ohms or reciprocal ohms on a linear scale,4 and a bridge which reads directly in specific conductance units. This la tte r bridge was designed especially for m easuring sugar ash.
Au t o m a t ic Te m p e r a t u r e Co m p e n s a t i o n—Besides the above improvements, autom atic tem perature compensation has been developed for b o th H-ion and conductivity appara
tus.
C O N T R O L IN V A R IO U S IN D U S T R IE S
In the following sections it has been found m ost convenient to divide up th e description of th e different types of control under the headings of th e various industries in which the particular control is operating. In a few industries both H-ion and conductivity controls are being utilized b u t in the majority th e developm ent has not progressed to this extent.
M e r c e r iz in g I n d u s tr y
Some of the first adaptations of conductivity control were made in the mercerizing ind u stry .5 Among th e several pos
sible applications in this industry, th e control of the acid bath, which is used for neutralizing th e caustic carried over in the yarn from th e mercerizing bath, is one of th e m ost important. Close control in this b a th is essential b oth to
4 To be published in th e n e ar fu tu re.
* Parker, G reer, a n d B arb a. A m . D yestu ff Replr., 16, 49 (1927).
increase th e uniform ity of the dyeing and to prevent the deterioration of the yarn. The control obtained autom at
ically is several times as accurate as th a t obtained by other methods.
In Figure 6 is shown a record obtained during the operation of autom atic control in a p lan t th a t has been using the m ethod successfully for about four years. In this type of control a solenoid valve, placed in th e acid line, is operated autom at
ically to keep th e b ath in the neighborhood of 3 per cent acid.
W hen th e record is a t th e left of the line on th e chart, which represents a concentration of 3 per cent, th e valve is open, and when a t th e right it is closed. If increased accuracy is desired, a by-pass m ay be used in the chemical supply line, to supply th e minim um requirem ents of the system, while the solenoid valve supplies a slight excess. However, this type of control is capable of accuracy only in those cases where a tank or pond is available in which th e cells m ay be placed and in which both mixing and equalization m ay take place. I t is also limited to those cases where th e flow is essentially constant.
In Figure 7 are shown the acid bath (at another plant) and the conductivity cell (indicated a t A ). Figure 8 shows the concentrated acid tank A, the solenoid valve B, and the recorder-controller.
P ow er P la n ts
Su r f a c e Co n d e n s e r Le a k a g e—In power plants there are m any problems th a t m ay be solved by electrom etric control. One of the m ost im portant of these is th e detec
tion of surface condenser leakage, especially in stations using salt w ater for cool
ing. T he p r o m p t detection of leakage by conductivity in
strum ents operating w ith alarm contacts h a s eliminated the expense of cleaning boilers which other
wise w o u ld h a v e been “ salted up.”
T he same measure
m ent in plants using s u r f a c e w a t e r for c o o lin g is o n ly of slightly less impor
tance, since meas
urem ents of leakage are n e c e s s a r y to prevent scaling of
F ig u r e 4— B rid g e C i r c u i t f o r C o n d u c t i v i t y R e c o rd e r
th e boilers and to determine th e efficiency of th e turbines.
T he U nited S tates N avy was one of th e first to adopt sig
nal-light conductivity control for detecting condenser leak
age. Figure 9 shows a four-point controller used on th e new airplane carriers. T he conductivity cell used m ost widely in these measurem ents has been shown in Figure 1.
If a recorder is used, w ith a cell in the condensate, the readings m ay be interpreted as p arts per million of dissolved solids. If a m easurem ent of the pounds of w ater per hour leaking into th e condenser is required, it is also necessary to measure a sample of condensed steam which is free from leakage.4’6
H - Io n Co n t r o l o f Bo i l e r Fe e d Wa t e r—H-ion control of boiler feed w ater has recently been perfected.7 This is another im portant power plant application. The autom atic installation in the Public Service Gas & Electric Com pany’s
< K eeler, Power, 55, 126 (1922).
1 P a rk e r a n d G reer, J . A m . Water W orks Assoc., 16, 602 (1926).
662 I N D U S T R I A L A N D E N G I N E E R IN G C H E M I S T R Y Vol. 19, No. 6
M e r c e r n e d Colton e m e r g e s -
■from b a th r / i t h stiqht am ount o f free su lfu ric a c id 'All o f daOH
used for.
mercerizing*
cof ion not -m neutralized £ the Sulfuric a c id ——
station a t P erth Amboy, N. J., is shown in Figure 10. The control is operating to regulate the addition of caustic soda and sodium phosphate to the boiler feed w ater and to keep the la tte r a t a constant pH. T he advantages are an increase in uniform ity of th e alkalinity in the individual boilers from day to day, and also in the boilers as a whole. This has resulted in less blow-downs. The control likewise acts as a degree of protection from condenser leakage,-since additional chemicals will be added autom atically to compensate for any leakage. In Figure 11 are shown the daily operating
F ig u r e 5— C o n d u c t i v i t y R e c o r d e r
results obtained over three periods of two m onths each, dur
ing the first of which hand control was in use, during the second the control was by hand b u t governed by the recorder readings, and the third was a period of autom atic control. The maximum, minimum, and average daily alkalinities of the bank of boilers are indicated on the curves—th e circles represent
ing the averages. I t can easily be seen th a t th e autom atic control has enabled th e keeping of the boiler alkalinity within much closer lim its th a n was obtained by either of the other two types of control.
In Figure 12 is shown a record of the H-ion control. This illustrates a second ty p e of control, which may be called the tim e lag-proportional step type. The recorder operates in two cycles—a recording and a controlling cycle—th e timing of which m ay be easily changed to suit the conditions of any given problem. During th e recording period a record of H-ion concentration is m ade and this period continues until the record has had tim e to register the effect of the last op
eration of th e m otor-operated valve. A t this point the con
trol cycle begins and an auxiliary e. m. f. is thrown in circuit, which is equal to the e. m. f. of the electrodes when th e H - ion concentration is a t th e desired value. The recording carriage imm ediately sta rts to move over to th e e. m. f. rep
resented by this control point and the valve sta rts operating in such a direction as to correct th e H-ion concentration to its desired value. W hen the recording carriage reaches th e control voltage, the m otor, which operates the valve, is thrown out of circuit. T he displacem ent of th e valve is th u s proportional to the deviation of the H-ion record from th e desired value.
From th e record in Figure 12 it is evident th a t the plant was sh u t down ab o u t 1:00 a. m. The caustic added during th e last operation of th e valves was sufficient to keep the water in th e feed heaters alkaline until the feed pum ps op
erated for a short tim e a t 3:00 a. m.
Since the position of th e valve never deviates much from th a t required to supply the correct q u an tity of chemicals, this type of control is applicable even in those cases where
no equalizing ta n k is available and where there is a consid
erable change in flow.
The proper setting of the control point is determined from the daily alkalinity analysis of the boiler water. By changing the setting to correspond to this analysis, it is, of course, evidept th a t any errors due to inequalities among the tung
sten electrodes are largely eliminated. When operated in this m anner, electrodes have been in successful use over periods as long as six weeks. In this particular installation, where the pH averages about 8, it has been found that the electrodes are .practically free from drift.
Ac i d Tr e a t m e n t o f ' Ze o l i t e- So f t e n e d Wa t e r—In some of the plants using zeolite-softened water, sulfuric acid is being added both to reduce the boiler alkalinities, which m ay build up to a dangerously high value, and to m aintain a required sulfate-caustic ratio. The flow-type quinhydrone electrode (Figure 3) has been successfully used, in this application, to hold the acid-treated water to a def
inite H-ion concentration. A utom atic control appears feasible, b u t a t present the recorder readings are used as a guide for the proper setting of a flow-proportioning device.
When kept a t a constant H-ion concentration, additional acid is added if the alkalinity of the u n treated water increases.
I t would therefore be expected th a t this control would supply a feed w ater having an approximately' constant sulfate- bicarbonate ratio which, after being concentrated and broken down (to caustic) by a definite degree in th e boiler, would provide a definite sulfate-caustic ratio. In the first plant to use H-ion control this desirable result has been accom
plished w ithin close limits. This m ethod presupposes an accurate control of th e boiler blow-down and this has been supplied by conductivity measurem ents.
Co n t r o l o f Bo i l e r Bl o w- Do w n Po i n t—The control of the boiler blow-down point is a very im portant electro
m etric application, from th e standpoint of both saving heat and the prevention of priming and scaling. Conductivity m easurem ents have been used successfully' for this purpose
F ig u r e 6— C o n d u c t i v i t y R e c o rd in C o n t r o l o f A cid B a th in M e r c e r iz in g P ro c e s s
for several years. W hen a very uniform m ethod of feed- w ater trea tm e n t is used, such as zeolite softening or auto
m atic H-ion control, th e conductivity of th e boiler water (at a definite tem perature) may' be related to its concentration.
In some cases th e alkalinity has been found practically pro*
Proper concentration o f h7S04 to insure, complete neutratiiation o f NaOH held by cotton when coming from No OH rot
Range o f C o n tro l1 0.15%
June, 1927 I N D U S T R I A L A N D E N G I N E E R IN G C H E M I S T R Y 663 portional to the conductivity. C onductivity measurements,
of course, cannot distinguish between the accum ulation of salts and the alkalinity. The hydroxyl ion has approxi
mately twice the m obility of any other ion in such a mixture, so the conductivity measurements, in m ost cases, are found to be rather closely related to the causticity. W hen the
Figure 7— M e r c e riz in g B a t h w i t h C o n d u c t i v i t y C ell I n s t a l l e d
salts and the causticity are kept in a definite ratio, as best boiler operation undoubtedly dictates, it is evident th a t the conductivity m ay be used to measure th e total concentration.
Measuring the conductivity of boiler w ater with a portable instrument, calibrated in conductance units, is consider
ably easier than an analysis by titration. The ideal m ethod of measurement would consist in the installation of a cell inside the boiler. This is impracticable, a t least for high- pressure boilers. However, in Figure 13 is shown a cell which has been installed in a continuous blow-down line a t 150 pounds pressure. Indications are th a t the insulation will last a t least two m onths under these conditions, after which it may be renewed. In this installation a record of boiler-water conductivity is being obtained and the blow
down valve is adjusted to keep this q u an tity constant. Anal
ysis has shown th a t by this m ethod the alkalinity of the boiler has been kept w ithin1 =±= 10 p. p. m.
Co n t r o l o f Co n c e n t r a t i o n i n t h e Ta i l Ra c e o f Ev a p
o r a t o r s—The control of evaporator blow-downs is closely
related to th a t of boilers, w ith th e advantage in the former that the conductivity cells m ay be installed either in th e blow-down line or directly in th e evaporator. These meas
urements have resulted in less scale form ation and in the saving of heat. An alarm m ay be used to indicate the cor
rect time for a blow-down. I t would also be feasible to op
erate a blow-down valve autom atically, to keep the conduc
tivity in the evaporator a t a constant value.
Au t o m a t ic Di s c a r d i n g o f Co n t a m i n a t e d Di s t i l l a t e—
Evaporators are frequently subject to priming, and in sev
eral plants autom atic controls have been installed for by
passing to the sewer any distillate having a conductivity above a certain value. T his is an im portant precaution in those plants which, in increasing numbers, are supplying
“ make u p ” by evaporators. In this application a controller alone has been used w ithout a record being obtained.
W a ste D isp o sa l
An autom atic H-ion control has been recently installed a t W inston-Salem in the sewage disposal p lan t which is being operated by the “ direct oxidation” m ethod. The control is of th e tim e lag-proportional step type. T he recorder-con- troller, gear reduction, and milk-of-lime dosing apparatus are shown in Figure 14. The last m entioned device8 con
sists of a short flume w ith a wier a t each end. One end of th e flume serves as an overflow return, while the chemical feed flows over the wier a t the other end. T he flume is tilted autom atically to supply more or less lime to th e sewage.
Although H-ion or conductivity control operate to add chemicals in proportion to the flow, in this installation it was found th a t the combination of a long-time lag and ex
ceedingly rapid fluctuations in th e flow prevented the re
quired accuracy from being obtained. Consequently', the apparatus shown in Figure 15 was installed in connection w ith a flowmeter. This device operates upon th e “ follow u p ” principle, and if the flow increases or decreases the chem
ical feed is increased or reduced in approxim ately th e same proportion. The H-ion control serves to correct this rough adjustm ent to give a solution of constant H-ion concentra
tion. The effluent is being kept a t about 50 p. p. m. excess causticity and, as it is well known, this lies well over on the insensitive p a rt of an H-ion titration curve. A slight differ
ence in voltage of the tungsten electrodes is liable to intro
duce a considerable error. A t this causticity the electrodes also exhibit a very slow drift to higher voltages. These difficulties have been overcome by using two electrodes in parallel, by changing one electrode every day, b y using them in rotation and keeping them in a saturated sodium phosphate
• D esigned by th e D irect O xidation Process C orp o ratio n .
F ig u r e 8— A cid T a n k . S o le n o id V alve, a n d R e c o r d e r - C o n t r o lle r I n s t a l l e d i n M e r c e riz in g P l a n t
664 I N D U S T R I A L A N D E N G I N E E R IN G C H E M I S T R Y Vol. 19, No. 6 solution when not in use. The effluent is titra te d for caus
ticity shortly after placing a new electrode in service and th e setting of the control points adjusted accordingly.
T his installation represents th e m ost difficult th a t has been m et in practice. A t a lower causticity th e drift in voltage disappears and the electrodes become more sensi-
F ig u r e 9— F o u r - P o i n t S i g n a l - L i g h t S a l i n i t y C o n t r o l l e r
tive. In spite of these difficulties, however, th e combined control has been able to keep the effluent w ithin approx
im ately =*=15 p. p. m. causticity. In m ost waste disposal problems it is believed th a t th e addition of lime could be controlled more accurately and w ithout th e necessity for th e flow-proportioning device.
Another application which promises success in th e sewage disposal field is a control upon th e addition of acid, which is necessary for obtaining satisfactory rates of filtration, in th e activated sludge process. The flow-type quinhydrone electrode has been tested in this application and preliminary results are encouraging.
S u g a r I n d u s tr y
In both th e beet and cane sugar industries there are several im portant applications for electrometric control. Probably none of these is more im portant than the second carbonation of beet sugar. H-ion records have been obtained w ith the tungsten electrode, in both this process and in th e defecation of cane sugar.9 In both cases a considerable improvem ent in control was obtained when the operator was using the recorder chart to determ ine th e proper setting of thejvalve.
An experim ental installation of autom atic control of the liming of raw cane juice is being operated during the present season in Porto Rico. Tungsten electrodes are being used in connection w ith the tim e lag-proportional step ty p e of control and the tilting weir box shown in Figure 14.
A nother installation is using an H-ion recorder during th e present cam paign in Cuba. T he recorder readings are being used in connection w ith signal lights to determ ine the proper valve opening for th e addition of lime in the defe-
• B alch a n d P ain e, Planter Sugar M fr., 75, 347 (1925).
cation process. This recorder has a scale reading in pH units.
T he readings of th e tungsten electrode are checked against the quinhydrone electrode, and if there is a discrepancy in the readings the pen is shifted to give the correct value. The flow-type tungsten electrode (Figure 16) is used in this ap
plication. T he solution is cooled to th e neighborhood of 60° C. by flowing through the cooling coil to the left. It then flows up p a st th e tungsten electrodes and calomel cell.
A utom atic tem perature compensation is provided. The additional valves shown in th e photograph provide means for draining the cooling oil and blowing live steam through the ap p aratu s for cleaning and sterilizing purposes.
T he tungsten electrodes have invariably been found to indicate correctly changes in H-ion concentration. In some solutions, however, they have been found to possess a slightly different pH-voltage characteristic from th a t determined w ith buffer solutions. In these cases, if an auxiliary method for checking is used, and if th e control setting or the pen is shifted accordingly, a quite satisfactory control or record m ay be obtained. Since some type of auxiliary check, such as a titra tio n or a m easurem ent w ith th e quinhydrone elec
trode, is generally in use already, this lim itation is not serious.
A check is usually necessary not more frequently than once a day.
T he dip-type quinhydrone electrode w ith portable poten
tiom eter, as shown in Figure 17, is being used satisfactorily by several sugar companies for th e determ ination of H-ion concentrations. This com bination has been found exceed-
F ig u r e 10— R e c o r d e r - C o n t r o lle r a n d A u t o m a t i c V alve Used in B o ile r F e e d - W a t c r C o n tr o l
ingly convenient, and routine m easurem ents m ay be taken probably more rapidly th a n by any other method. This m ethod is particularly adapted to th e measurem ent of the dark-colored solutions where colorimetric methods fail.
M any sugar companies are likewise using the conduc
tiv ity m ethod for th e determ ination of sugar ash.10 A new bridge, which reads directly in specific conductance, and which has h and tem perature compensation, has been devel
oped for this measurem ent. This bridge (Figure 18) has
10 F o r vario u s references reg ard in g th is m eth o d see Z erban and Sattlcr, Facts A bout Sugar, 21 (D ecem ber 4, 1926).
June, 1927 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 665
i
BOILER ALKALINITY, MAX., MIN. AND AVERAGE
F ig u r e 11— I m p r o v e m e n t in A l k a l i n i t y C o n t r o l o f B o ile rs d u r i n g A u t o m a t i c C o n tr o l
simplified th e m easurem ent to th e p o int where the deter
mination is easy even for a person who has never previously made’a conductivity m easurem ent.
T h e W a terw o rk s F ield . - H i -
n - n - 2 5 - t t t t - 6 : 0 0 A .M .
”
rt
V
>1 / i
k
<
1 -if-?
S. -
r o'.c>0 RM.
1 1 1 -5
¡9 1 1 1
igure 12— R e c o rd of A u t o m a t i c C o n tr o l of B o ile r F e e d W a t e r
T he w a te r w o r k s field presents m any problems which m ay b e s a t i s f a c t o r i l y solved by e l e c t r o - m etric control. I t is well known th a t there is a certain pH value a t which a minimum q u an tity of alum is required for best clari- f i c a t i o n . C o n s e quently, th e record
ing of pH is an im
p o rta n t factor in this field. Some success has been o b t a i n e d w ith the t u n g s t e n e l e c t r o d e , 11 b u t in cases where th e pH is below 8 an increase of a c c u r a c y (to =*=0.05 p H ) h a s b e e n ob
tained w ith th e flow- type q u in h 'y d r o n e electrode.
11 P a rk e r a n d B aylis, J . A m . W a t e r W o r k s Assoc., 15, 22 (1926).
M any w ater purification plants add lime as a corrective to raise the pH and prevent troubles from corrosion and “ red w ater.” In this application the tungsten electrode has given satisfaction and where the pH averages less th a n 8 the quinhydrone electrode is applicable. Figure 19 shows an H-ion record obtained a t th e Montebello Filters, Baltimore, M d. T he record was m ade w ith tungsten electrodes while recording the pH of the w ater after th e addition of lime.
T he record to the right was obtained before th e operator was told to w atch th e recorder chart, and th a t to th e left while th e operator was opening the valve in such a m anner as to keep the pH a t the proper value.
' 1 ' fl f[ [ S u lf u r ic A cid M a n u fa c tu r e I n t h e c o n t a c t
process of s u l f u r i c acid m anufacture the double-cell principle of conductivity meas
urem ents has been in use m any years for keeping th e concen
tration of th e absorb
ing acid a t its proper
value. U p to this tim e th e m easurem ents have been m ade w ith portable indicators and recorders. Owing to th e rapid change of conductivity over th e required range of concen
tration, it is evident th a t autom atic control should be capable of giving considerable accuracy.
M is c e lla n e o u s A p p lic a tio n s
In nickel-plating b ath s th e dip-type quinhydrone ^elec
trode has proved very successful for measuring p H .12 In
l! P a rk e ra n d G reer, Trans. A m . Elcctrochem. Soc., 49, 451 (1926).
F ig u r e 13— B o ile r W a t e r C ell
666 I N D U S T R I A L A N D E N G I N E E R IN G C H E M I S T R Y Vol. 19, No. 6
C o u r t e t y o f D i r e c t O x i d a t i o n P r o c e t t C o r p o r a t i o n F lg u r e 14— R e c o r d e r - C o n t r o lle r a n d T l ltJ n g - L im e - F e e d D e
vice i n S c w a g e D ls p o sa l C o u r l e t y o f D i r e c t O x i d a t i o n P r o c e t t C o r p o r a t i o n F lg u r e 15—.f l o w - P r o p o r t i o n i n g D evice l n S e w a g e D isposal
F lg u r e 17— D ip -T y p e Q u ln h y d r o n e E l e c tro d e w ith P o rtab le P o t e n t i o m e t e r
F ig u r e 16— F lo w - T y p e T u n g s t e n E l e c tro d e a s U sed i n S u g a r M a n u f a c t u r e
larger installations it is quite likely th a t autom atic control of this q u an tity would be found advantageous.
M any other industries, such as th e paper, baking, flour, dairy, tanning, ceramic, lithopone, etc., have found the dip- ty p e quinhydrone electrode to be the m ost convenient m ethod of m aking H-ion measurem ents and are gradually adopting it.
There are several miscellaneous uses to which conductivity and H-ion m easurem ents have been put. Chemical lab
oratories which rely greatly upon the p u rity of their dis
tilled w ater have installed conductivity recorders. The leakage of river w ater into artesian wells has been detected
by conductivity methods. These m easurem ents have also been used to detect the presence of w ater in oil wells, to de
te ct contam ination of river w ater by trade wastes, to meas
ure concentration in various types of solutions, etc. 1»
fact, there seems to be scarcely an industry in which chem
istry plays an im portant role th a t would not find some ad
vantageous use for electrom etric m easurem ents or control.
D IS C U S S IO N
T he progress of electrom etric control has depended almost entirely upon th e developm ent of simplified and fool-proof cells and electrodes. The electrical m easuring and control apparatus has been in a high sta te of perfection for se v e ra l
June, 1927 I N D U S T R I A L A N D E N G I N E E R IN G C H E M I S T R Y 667 years. The present expansion has been due alm ost entirely
to recent im provements in cells and electrodes which have finally been dem onstrated to be commercially practicable.
F ig u re 18—S p e c ific C o n d u c t i v i t y o r S u g a r - A s h B rid g e
In applying electrom etric control to industry, it is a t times very difficult to predict w hether a given problem is likely to be solved by this means. I t is likewise alm ost impossible to predict the correct range for a recorder or controller, w ith
out making prelim inary m easurem ents a t th e p lan t in which the control is to be installed. Frequently' it is advisable to permit th e operator to m ake prelim inary m easurem ents in order to collect d a ta for calibrating th e final instrum ent.
While making these m easurem ents he gains considerable knowledge and later no difficulty is experienced in changing over to recording or control apparatus.
Recording apparatus which can be applied to a large num ber of quite different problems has helped to solve this diffi
culty'. T he recorder th a t uses a reference cell, in which various solutions m ay be placed, is a good example of this ad ap t
ability. E ven in using this instrum ent, however, the proper range m ust be employed in order to obtain th e desired sen
sitivity. Instrum ents have also been m ade w ith variable ranges in an attem p t to solve these difficulties.
While th e preced
ing d e s c r i p t i o n in
cluded th e m ost im p o rta n t fields where electrom etric control is a t present employed in industry, no a t
te m p t will be m ade to summarize the possi
ble uses to which such control m ay be ap
plied in the future.
In all th e cases cited there are a t least one or more installations in successful opera
tion a t th e present tim e. Present prog
ress is n e c e s s a r i l y F iftu re 19—H - I o n R e c o rd , w i t h T u n f t s t c n , , , , E l e c tro d e , a t t h e M o n te b e llo F i l t e r s , S lO W , O W i n g to the B a l t i m o r e , M d .
n e c e s s i t y for over
coming various obstacles, m any of which are peculiar to partic
ular installations. After more experience has been obtained along these lines, it is believed th a t the subsequent progress will be relatively rapid.
Flames of A tom ic H y d ro g en 1’
B y Ir v in g L a n g m u lr
Re s e a r c h La b o r a t o r y, Ge n e r a l El e c t r i c Co m p a n y, Sc h e n e c t a d y, X . Y.
T
HE heat carried away from an incandescent wire by a surrounding inert gas a t ordinary' tem peratures increases roughly in proportion to th e 1.9th power of the absolute tem perature, T, of th e filam ent.2 This relation holds, for example, for such gases as nitrogen, argon, and mercury vapor up to th e tem perature of melting tungsten, 3660° K. In the case of hydrogen, however, abnormal results were obtained in experiments m ade a t high tem peratures. Up to about 1700° K . th e norm al exponent of 1.9
"'as observed, b u t a t higher tem peratures the exponent in
creased until a t 2600° K . and above it was about 5.0. A t 3400° K. the heat conducted by hydrogen was tw enty-three tunes as great as th a t carried b y nitrogen under similar con
ditions.
Xernst3 in 1904 had developed th e theory of h eat conduc
tion in a dissociating gas and had shown th a t dissociation results in a great increase in th e h eat conductivity. The dissociation products diffuse from th e h o t portions of the gas
1 Received April 19, 1927. A m ajo r p a rt of th e su b jec t m a tte r of th is paper was covered in an ad d ress u n d e r th e sam e title delivered a t th e GeDeral Meeting of th e Am erican Chem ical Society, Philadelphia, P a ., Sep tem b er 8, 1926. Prelim inary p u b licatio n s h av e ap p eared in th e Gen. Elec. Rev., 29, 153, 160 (1926).
! Langmuir, Trans. A m . EJeclroehem. Soc., 20, 225 (1911); P hys. Rev., 3M 0 1 (1912); J. A m . Chem. Soc.. 34, 860 (1912).
•B o ltrm an n F e stsc h rift, p. 904 (1904).
into th e cold portions and there, b y recombining, give up th e large energy of the chemical reaction. This suggested th a t th e abnorm al h eat conductivity of hydrogen a t high tem pera
tures is due to dissociation of the hydrogen into atom s ac
cording to the reaction
H 2 = 2H (1)
An abnorm al h eat conductivity m ight, however, be due to th e form ation of an endothermic polymorphic form of hy
drogen such as H 3, corresponding, for example, to ozone.
According to th e law of mass action, the degree of dissociation of a gas into atom s m ust be greater a t low pressures th a n a t high, whereas th e opposite would be true if molecules con
taining more th a n two atom s were formed.
A t tem peratures below 1700° K . th e h ea t carried away b y convection and conduction was greater a t higher pressures of hydrogen th a n a t lower pressures. F or example, a wire of 0.0706 mm. diam eter a t 1500° K . dissipated over twice as m uch energy in hydrogen a t 760 mm. as in hydrogen a t 50 mm. pressure. A t tem peratures above 2700° K., how
ever, more energy was dissipated a t 50 mm. th a n a t 760 mm. There are evidently two factors acting in opposite directions. Since th e h eat loss by convection and normal conduction increased w ith tem perature according to a law which had been determined, it was possible to extrapolate
