The J o u r n a l of In d u s tria l and Engineering Ghemistry
P u b l i s h e d b y T H E A M E R I C A N C H E M I C A L S O C I E T Y
Volume V M ARGH, 1913 No. 3
B O A R D O F E D I T OR S Editor: M. C. W h i t a k e r
Associate Editors: G. P. A dam son, E . G. B ailey, H . E . B arn ard, G. E . B arto n , A. V . B leininger, Wm. Brady, C. A . B row ne, F . K . Cam eron, F . B . C arp enter, C. E . Caspari, V . C oblentz, W . C. Geer, W. F. Hillebrand, W . D. H orne, T . ICamoi, A . D . L ittle , C. E . L ucke, P . C. M cllh in ey , W m . M cM urtrie, J. M. Matthews, T . J. P ark er, J. D . P enn ock, W . D . R ich ardson , G. C. Stone, E . T w itch ell, R . W ah l, W. H. Walker, W . R . W h itn e y , A . M. W righ t.
P u b lis h e d m o n th ly . S u b s c rip tio n p ric e t o n o n -m e m b e rs o f th e A m e ric a n C h em ica l S o c ie ty , $ 6 .0 0 y e a r ly . F o re ig n p o s ta g e , s e v e n ty -fiv e c e n ts , C a n a d a . C u b a a n d M ex ico e x c e p te d .
E n te re d a s S e c o n d -c la ss M a tt e r D e c e m b e r 19, 1908, a t th e P o st-O ffic e a t E a s to n , P a ., u n d e r th e A c t o f M a rc h 3 , 1879.
Contributiofis should be addressed to M. C. Whitaker, Columbia U niversity, New York City
Communications con cern in g advertisem ents should be sen t to L. R. Hudson, 42 West 39th St., New York City
Subscriptions and claim s lor lost copies should be referred to Charles L. Parsons, Box 505, W ashington, D. C. No claim s w ill be allow ed u n less made w ithin 60 days
Es c h e n b a c h Pr i n t i n g Co m p a n y, Ea s t o n. Pa.
T A B L E O F C O N T E N T S Editorials:
The Perkin M ed al ... 180
The Annual M eeting a t M ilw a u k e e ... 180
The Bureau of M in es... '... 180
Original Pa p e r s : Notes on Mine G as P ro b lem s. B y G eo rg e A . B u rr e ll. . 181
The D estructive D istilla tio n of S ew a g e S lu d g e. B y Augustus H . F is k e a n d R ic h a rd B . E a r le ... 186
Alloys of C o b alt w ith C h rom iu m a n d o th e r M etals. B y Elwood H a y n e s ... 189
The R elation of th e P ro d u c tio n of A lu m in a to th e F i x ation of N itro g en . B y S am u e l A . T u c k e r ... i g r On the R elation sh ip b e tw e e n th e W e ig h t of th e S u g a r Beet and th e C om p osition of I t s Ju ice. B y J. A rth u r Harris and R o ss A ik e n G o r t n e r ... 192
Methods for T e s tin g C oal T a r , a n d R e fin e d T a r s, O ils and Pitches. B y S. R . C h u rc h ... 195
The Com position of S a lin e s in S ilv e r P e a k M arsh, N e vada. B y R . B . D ole, w it h a n a ly se s b y W a lto n V a n W inkle and A . R . M e r z ... 196
Composition of th e W a te r of C ra te r L a k e , O reg on . B y W alton V a n W in k le a n d N . M. F in k b in e r ... 198
Action of F e rm e n tin g M an u re on R e e n fo rcin g P h o s phates. B y W . E . T o ttin g h a m a n d C. H o ffm a n 199 The G ay-L u ssa c M eth o d o f S ilv e r D e te rm in a tio n . B y Frederic P . D e w e y ... 209
The S u lfo cy a n a te-P e rm a n g a n a te M eth o d fo r C o p p er in Ores. B y D . J. D e m o r e s t... 215
E lectrolytic D ete rm in a tio n of C op p er in O res, C o n ta in ing Arsenic, A n tim o n y or B ism u th . B y D . J. D e m orest... 2 16 An E lectro lytic M ethod for th e D e te rm in a tio n of T in in Canned F ood P ro d u cts. B y A lle rto n S . C ushm an and E v e re tt B . W e t te n g e l... 2 17 Potassium P e rm a n g a n a te in th e Q u a n tita tiv e E s tim a tion of Som e O rg an ic C om p ou nd s. B y C. M . P en ce. 218 Some Properties of K o ji-D ia s ta se . B y G . K i t a ... 220
Application of th e A m m o n iu m C a rb o n a te M eth o d for the D eterm in ation of H u m u s to H a w a iia n . Soils. B y J- B. R a th e r ... 222
Laboratory a n d Pl a n t: The N ew H ig h . F o rm of S u lfu r ic A c id C h am b er. B y F. J. F ald in g a n d W . R . C a t h c a r t ... 223
Technical A c co u n tin g a n d C hem ical C o n tro l in S u g a r M anufacture. B y D a v id L . D a v o ll, J r ... 231
A M odification of th e P a rr T o ta l C arb o n A p p a ra tu s . B y C. E . M illa r... 234
Improved A p p aratu s for T e s tin g th e J e lly - S tr e n g th of Glues. B y E . C. H u lb e r t ... 235
Useful V a lve . B y N a th a n S m ith ... 235
The Needs of th e M in in g I n d u s try . B y J. F . C all- breath...6 ... 236
T h e C h em ica l E n g in e e r a n d In d u s tria l E fficie n cy . B y W . M. B o o t h ... 237
Pe r k i n Me d a l Aw a r d: P re se n ta tio n A d d ress. B y C. F . C h a n d le r ... 241
A d d re ss of A c c e p ta n c e . B y Jam es G a y le y ... 241
T h e V a lu e of E x p e r t O pinions. B y H e n r y M. H o w e . . 246
D r. G a y le y ’s In te r e s t in E d u c a tio n . B y E d w a rd H a rt. 247 T h e N e w A g e . B y R o ss ite r W . R a y m o n d ... 249
Cu r r e n t In d u s t r i a l Ne w s: T h e P ro d u c tio n of C alciu m C arb id e a n d C y a n a m id e in N o r w a y ... 251
P o ta ssiu m S a lts from S e a w e e d ... 251
T h e C o b a lt O x id e M a r k e t... 251
T h e M ark ets fo r C a u stic S o d a a n d S o d a A s h ... 251
T h e P re s e rv a tio n of T im b e r ... 252
/ T a r as a F u e l for O p e n -H e a rth F u r n a c e s ... 252
A N o v e lt y in G a s E n g in e s ... 252
T h e B ritish M etal T r a d e in 1 9 1 2 ...: ... 252
Iro n a n d S te e l S ta t is t ic s for 1 9 1 2 ... 252
T h e P ro d u c tio n of A m m o n iu m S u lfa te in 1 9 1 2 . ... 253
T h e P e tro le u m In d u s try in th e U n ite d S ta te s in 19 12. 253 C on d ition s of th e P la te G la ss I n d u s try in th e U n ite d S t a t e s ... 253
T h e P r e s e n t S ta t u s of th e S u g a r I n d u s try . . . ... 254
T h e P ro d u c tio n a n d C on su m p tio n of R u b b e r in 1 9 1 2 . . 254
T h e U tiliz a tio n of B la s t-F u rn a c e a n d C o k e -O ve n G ases. 254 A b u se s in W a te r F ilt r a t io n ... 255
T h e C o st of H y p o c h lo rite D isin fe c tio n ... 255
T h e P a p e r I n d u s try of J a p a n ... 255
T h e G erlach D r ie r ... 256
A r le d t e r ’s S a v e - A ll A p p a r a t u s ... 256
U se s of C a s t S ilic o n ... 257
No t e s a n d Co r r e s p o n d e n c e: N o te s on th e In flu e n ce of th e L in ie -M a g n esia R a tio u p on P la n t G r o w th ... 257
A n Im p ro v e d M eth o d of C ru d e F ib e r E s tim a tio n 258 A m e ric a n M ine S a fe t y A s s o c ia tio n ... 258
T h e A n a ly s is of O rg a n ic D y e s tu ffs ... 259
P la tin u m T h ie f ... 259
M ag n esite in L o w e r C a lifo rn ia ... 259
D e fe ctiv e A rtific ia l S ilk ... 260
In cre ase d W o rld ’s C on su m p tio n o f N it r a t e ... 260
T h e E ffe c t of E x p o su re on B itu m en s— A C o rre ctio n . . 260
T h e D e te rm in a tio n of " V o la t ile ” in C o a l— A C orre ctio n . 260 T h e D e te rm in a tio n of L im e in C ow F e c e s— A C o rrection . 260 Bo o k Re v i e w s: T ra n s a c tio n s of th e A m e ric a n C e ram ic S o c ie ty ; P r e p a ra tio n a n d U ses of W h ite Z in c P a in ts; R e fra c to rie s a n d F u rn a c e s ; T h e S cien ce of H y g ie n e ... 260
Ne w Pu b l i c a t i o n s... 263
Re c e n t In v e n t i o n s: ... : ... 264
Ma r k e t Re p o r t... 266
i8 o T H E J O U R N A L O F 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 Mar., 1913
EDITORIALS
T H E P E R K IN M E D A L
D a v y cautioned F a ra d a y not to indulge in im moder
ate exp ectation s of the rewards of Science. True, her gifts are not, as a rule, redundant, and th ey are lik ely, m oreover, to be som etimes capriciously b e
stow ed; b u t Science gives more precious rewards for excellence or success than those w hich can be e x pressed as ponderable quantities, and, am ong these, few are valued more highly than medals.
W e look upon a m edal as tangible proof of p re
em inence, for it is an indication of individual accom plishm ents— a token cast, in artistic mold, from a fusion of the golden opinions won b y illustrious work.
I t furnishes the individual w ith evidence as to the re
gard in w hich achievem ents are held b y his co-workers and fellow men.
On O ctober 6, 1906, a t a banquet given to Sir W il
liam H enry Perkin, a t Delm onico’s, N ew Y o rk , Dr.
W illiam H. Nichols handed to Sir W illiam the first im pression of the P erkin Medal, in gold. Dr. Nichols announced th a t this m edal would be given annually to th at chem ist residing in the U nited States who had accom plished the m ost valu able w ork in applied chem istry during his career, w hether this had proved suc
cessful a t the tim e of execution or publication, or had subsequen tly becom e valu able in the developm ent of industry. The P erkin Medal is therefore an a c know ledgm en t of conspicuous services to technical chem istry— a rew ard for the successful application of scientific m ethods to industry. I t is associated w ith the nam e of one of the m ost distinguished chem ists, the founder of the immense coal-tar industry, and the recipient of the highest m arks of distinction possible for Science to aw ard; and it is conferred in order to show high appreciation of and gratitu d e for the success of the recipient of the m edal in advancing chem ical industry in one or several of its branches.
In this w a y the ap p licab ility of chem istry to the arts and m anufactures is advanced, for someone eminent in the field of chem ical technology is indicated for the benefit of the aspiring technologist, and chem istry applied to the industries receives further recognition.
T h e lessons in m ethods which the labors of the m edal
ists afford m ust prove invaluable to all am bitious chem ists.
W hile the aw ard of the Perkin Medal is made b y the N ew Y o r k Section of the Society of Chem ical In d u stry, the largest and most prom inent of the A m er
ican sections of a great S ociety which em braces in its m em bership all— am ong the English-speaking races— th at is representative of enterprise and progress in relation to the chem ical arts, engineering, and in
dustries, y e t the P erkin M edal Com m ittee, which se
lects the m edalist, is constituted of representatives of different chem ical societies of this cou n try in addi
tion to a representation from the S ociety of Chemical In d u stry ; and, in m aking the selection, this Com m ittee shows how highly it appreciates the w ork of the one
so honored. I t is not required, as in the case of some §■
medals, th at a n y p a rticu lar so ciety e n jo y the credit and distinction of dissem inating the results of the en
quiries to w hich his fru itfu l ideas g iv e rise: the Perkin Medal is a m edal of m erit conferred on chemists and ' technologists residing in the U n ited States for ser
vices done in technical ch em istry, as determined by the scope, value and im portance, and w ith no restric
tions as to a n y definite field of endeavor. In being presented, therefore, w ith th e P erk in Medal, the re
cipient is sensible of the g rea t honor done him, and this sense of the honor is increased b y the recollection of the eminence of the preceding m edalists. Perkin, Herreshoff, Behr, A cheson, H all, F rasch, and Gayley!
How proud one m ust feel in being reckoned of their com pany!
T H E A N N U A L M E E T IN G A T M IL W A U K E E The fo rty-seven th annual m eeting of the American Chem ical S o ciety is to be held a t M ilwaukee, March 25th to 28th. T h e general h eadq uarters w ill beatthe H otel Pfister, and the m eetings w ill be held at Mar
q uette U niversity, located in th e business center of the city. T he local com m ittee is headed b y Mr. C. H.
H all, as Chairm an, and Mr. P. J. W eber, as Secretary.
The entertainm ent com m ittee is plan ning an inter
esting program , and special a tten tio n is being paid to preparations for the en tertain m en t of ladies, at such tim es as th ey cannot p a rticip a te in th e regular pro
gram . M any m an ufacturing p lan ts w ill be visited.
M ilwaukee affords excellent op p ortu nities to see the tanning and p ack in g industries; th e manufacture of iron and steel, engines— gasolin e and kerosene, by
product coke and gas, glue, refrigeratin g machinery, autom obiles, autom obile p arts and tires; shops and breweries. Most of these w ill be open to inspection by our members.
President V a n Hise has ex ten d ed a special invitation to the S ociety to visit the U n iv e rs ity of Wisconsin.
T he plans as outlined b y th e local com m ittee clearly indicate th a t this is to be an u n u su ally large and suc
cessful m eeting. The social, business, and scientific value of these m eetings is m ore and more a matter of im portance to the profession, and it is to the profession, therefore, th at we should look fo r support and cooper
ation. E v e ry chem ist should a tte n d a t least one meet
ing each year. W h y not begin a t M ilwaukee?
T H E B U R E A U O F M IN ES
The cryin g need of the B u reau of Mines for buildings ^ and equipm ent can be easily ap p reciated on reading D irector J. A . H olm es’ Second A n n u al Report, 'lhe am ount and value of the w o rk a lrea d y a c c o m p l i s h e d in mine safety and rescue dem on stration s, fuel investi
gations, explosive tests and stand ard ization, and other field work is am azing w hen one considers th a t the Bureau has never had a perm anent hom e. I t is a l m o s t incon
ceivable th at this im portan t d ep artm ent s h o u l d be
Mar., 1913 T H E J O U R N A L O F 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 181
housed in rented buildings. T h e d elays and expense, already 8150,000, incident to tem p o ra ry locations, seriously handicap th e w ork.
Thirty thousand men h ave been killed and n early twenty thousand seriously injured in the coal mines within the last ten years. T h e B u re a u ’s w o rk w ithin the past year has y ield ed a redu ction of five hundred in this annual sacrifice of life, b u t our losses in all m ines and quarries are so g re a tly in excess of those in other countries as to.be a v e ry discred itable co m m en tary on our mining m ethods. In the face of th e w onderful re
sults so far accom plished, th e m ine rescue w ork of th e Bureau has had to be cu rtailed and some im p ortan t phases entirely om itted, due to lack of equipm ent.
This one branch of th e B u re a u ’s w ork is of sufficient
im portan ce to m erit th e u nlim ited su p p ort of Congress.
T h e fa ct th a t the fuel testin g done b y the B u reau has saved the G overn m en t not less th an $ 1 0 0 , 0 0 0 per y e a r during the la st three years, w hile lab oring under th e m ost u n favorab le conditions im aginable, is an in d ication of w h a t can be exp ected if th e p rop er w orkin g conditions are provided.
T h e B u reau asks for the m odest ap propriation of
$500,000 for buildings and proposes to use the “ ch eap est sort of con stru ction th a t w ill be decen t to h a ve in a c it y .” I t w an ts noth in g ornam ental. I t asks o n ly for efficient w orkin g housing for the prosecution of its in vestigation s, and a review of th e v a lu a b le w ork a l
read y accom plished should serve to co n vin ce Congress of th e urgent needs of the B u reau of Mines.
ORIGINAL PAPLRS
NO TES ON M IN E G A S P R O B L E M S 1
B y Ge o r g e A . Bu r r e l l
The Bureau of Mines has accu m ulated considerable data regarding mine gases, as a result of the an alysis of gas samples collected in different m ines and as a result of experim ental w ork perform ed in the lab o ra tory. Some of the o b servation s are presented here, regarding the ex p lo sib ility and p h ysiological effects of mine atm ospheres, also regarding flame extin ctio n and after-damp.
E X P L O S I B I L I T Y O F M E T H A N E
The limits of e x p lo sib ility of m eth an e h ave been worked out ■ b y different in vestigators and results, which in the m ain are in accord w ith each other, have been determ ined in the lab orato ry. Some differences have been published b u t these are mainly due to the fa c t th a t different exp erim en t
ers have perform ed the w ork under different con ditions. Sufficient em phasis has not a lw ay s been placed upon the decided effect exp erim en tal conditions exert on the results. T h e size and shape of th e vessel employed, nature of source of ignition, i. <?., w h eth er flame, small electric sp ark or large electric flash;
ignition of m ixture from ab o ve or b elow ; m oisture in the mixture; and tem p eratu re and pressure, all m ay have some influence in determ inin g the lim its of explosibility of m ixtu res of com bu stible gases w ith air- A partial burning in a m ixtu re of a com bustible gas with air a lw ay s ta k e s place w hen the ignition temperature is reached, w h eth er an exp losive p rop or
tion of com bustible g as be present or not. T h e e x te n t of this burning w ill depend upon som e of th e conditions just referred to. B u t ex p losive lim its in the sense the terms are o rd in arily used h a ve reference to those percentages of inflam m able g as b etw een w hich self-propagation of flam e to all p a rts of a m ix ture occurs w ith ou t help from th e source of ignition other than th e ign ition of th e m ixtu re a t one point. I he sm allest q u a n tity of a n y co m b u stib le gas
" ich when m ixed w ith a ir (or o xy g en ) w ill enable
the ^ rescntcc* p e rm issio n o f th e D ire c to r of t h e B u re a u o f M ines a t h ,^ Wl,I?te r m eet>n £ ° f th e W e s t V irg in ia C oal M in in g I n s t i t u t e , P a rk e rs -
Urs' W- V a„ D ecem ber, 1912.
self-propagation of flam e to tak e place is term ed the low er lim it of ex p lo sib ility of th e gas. It is of v ita l im portance to m ining men of course, th a t the correct lim it of exp losib ility of m ethan e w ith air be know n.
L O W E X P L O S I V E L I M I T O F M E T H A N E A I R M I X T U R E S
M ore recent w ork has shown th a t th is va lu e is ab o u t 5.50 p er cent, m ethane and not 6 per cent, as is som e
tim es stated. E v e n 0.50 per cen t, is of significance.
M odern ven tilatio n aim s to keep the m ethane in mine air as far rem oved from the exp losive p rop ortion as possible. One p er cent, of m ethane in return air is considered a large q u a n tity . One h alf per cent, is som etim es tolerated. If the exp losive lim it for m eth ane is 5.5 per cent, and a m ining m anagem ent calls 6 p er cent, the low lim it of ex p lo sib ility, th e y are 0.5 per cent, nearer the exp losive p rop ortion th an th ey thin k.
Coquillon ignited m ethane-air m ixtu res in a closed vessel b y m eans of an electric spark, and p laced th e low er lim it of ex p lo sib ility a t 5.8 p er cent, m ethane.
L e C hatelier and M allard and B ou dou ard h a ve p laced th e lim it a t 6.0 per cen t. E itn e r determ ined the low er lim it of e x p lo sib ility of m ethan e to be 6.1 per cent. Clow es ob tained 5.0 p er cent, as th e low lim it o f ex p lo sib ility w hen the g as w as fired from below w ith a flam e and 6.0 per cent, as the lim it w hen th e gas w as fired from above. T e c lu found the low er lim it of e x p lo sib ility to be betw een 3.20 and 3.67 p er cent.
T e c lu 's valu es are q u ite outside of th e others m entioned here. T h e m ost recen t valu es are those obtained b y B urgess and W heeler w ho place the low er lim it of ex p lo sib ility betw een 5.5 and 5.7 per cent. N o d is
cussion of the different m ethods of exp erim en tation w ill be g iven here, th e object' being o n ly to c o n v e y th e idea th a t e x a c t d up lication of results b y different experim enters has not a lw ay s followed.
In the B u reau ’s la b o ra to ry an explosion could not be obtained .when a m ixtu re of m ethane and air co n tain in g less th an 5.5 p er cent, m ethane w as su b jected to th e actio n of a sm all I/ 8 inch sp ark from an ind u ction coil. T h e la tte r w as driven b y four d ry cells. T h e m ixtu re w as placed in a 100 cc. spherical vessel o ver
i8 2 T H E J O U R N A L O F 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 Mar., i9i3
m ercury. A n explosion could not be obtained w ith o .i per cent, less m ethane when the pressure was increased from one atm osphere to two atmospheres.
W ith 5.50 per cent, of m ethane, com bustion was not qu ite com plete. A nalysis of the products of com bus
tion showed, however, th at only a trace of com bustible gas rem ained unbum t. Pure m ethane was prepared b y the action of alcohol and m ethyl iodide on a zinc- copper couple.
A num ber of experim ents h ave been performed in the B u reau ’s lab oratory in which a flame has been used as the source of ignition. In some of those e x perim ents a spherical flask h avin g a ca p a city of one liter has been used. Some burning followed under these conditions when as little as 4.75 per cent, m ethane w as present. Ignition was effected from below. The burning extended as a cone about one-half of the w ay to the top of the flask. Inflam m ation in the m ixture increased w ith increasing percentages of m ethane.
A ll m ining men have of course noticed this behavior in m ixtures of com bustible gases and air. W ith very small percentages the inflam mation starts as a cap on the flame of t h e . safety lamp. The inflam m ation spreads from the source of ignition as the percentage of com bustible gas is increased. F in a lly conditions are right for a projection of flame throughout the m ixture. A t ab out 5.50 per cent, the low lim it of explosibility, the flame extends to all parts of the m ixture but travels com p aratively slow ly and can be followed b y the eye. W ith increasing proportions of methane, the explosion becomes more violent. It was observed th a t the partial burning in a m ixture containing less than 5.50 per cent, m ethane depended upon the several factors such as nature of ignition, shape of container, etc., bu t th at com plete explosion could not be obtained under several different conditions of experim ent tried w hen less than 5.5 per cent, of m ethane was present. In determ ining the low ex plosive lim it of m ethane-air m ixtures, the products of com bustion were exam ined to ascertain the com pleteness of the com bustion. In the experim ents th at follow, this w as not done unless otherwise stated.
The term explosion will be retained to m ean conditions when the flame filled the container as far as could be seen b y the eye. Inflam m ation will mean only a partial filling of the container b y the flash. The foregoing rem arks are prelim inary to a brief account of some experim ents regarding exp losib ility of fire
dam p, w hich are not so well known.
E F F E C T O F C A R B O N D IO X ID E O N T H E E X P L O S I B I L I T Y O F M E T H A N E
In explosions, as w ell as flame extin ction and p hysiological effects, the influence of carbon dioxide in mine air has usually been overestim ated. Carbon dioxide alw ays occurs in mine gas m ixtures in which explosive am ounts of m ethane are present and there is alw ays a greater oxygen deficiency than is produced when the m ethane is added to air for simple lab oratory experim ents. The follow ing experim ents show some
th in g about the explosibility of m ethane in'the presence of excessive proportions of carbon dioxide and when the oxygen is considerably reduced.
In the B u reau ’s lab orato ry, w hen 2.5 p er cent, of carbon dioxide was present in a m ixture, an ex
plosion followed w hen the m ethane w as raised to 5.83 per cent.
W ith 5.0 per cent, carbon d ioxide an explosion oc
curred when the m ethane w as raised to 6.25 per cent.
W ith 10.o per cent, of carbon d ioxide an explosion was obtained w hen the m ethane co n stitu ted 6.6 per cent, of the to ta l. A sm all sp ark from an induction coil w as the source of ignition. T h e presence of carbon dioxide narrows th e ex p losive lim its but it will be observed th a t even 10 p e rc e n t, o n ly raised the low lim it to 6.60 per cent.
E F F E C T O F R E D U C E D O X Y G E N O N T H E E X P L O S IB IL IT Y O F F I R E - D A M P
A spherical- flask h avin g a c a p a c ity of r liter was used in the follow ing experim ents: A m ixtu re of the follow ing com position was experim ented w ith:
P e r cen t.
C arb o n d io x id e ... 0 .0 3 O x y g e n ... 14 .0 0 M e th a n e ... 9 .4 0 N itro g e n ... 7 6 .5 7
W hen this m ixture was exposed to a flame from above inflam m ation occurred. T h e flame spread dow nward to the m iddle of th e flask, an d out toward the sides where it died. T h e eye could easily follow the course of the w ave. W h en the m ixture was ignited w ith a flame from below , it exploded with considerable force. A s fa r as the eye could see the flame filled the entire flask.
Fu rth er experim ents w ere m ade in w hich the oxygen had been reduced to 13 p er cent. T h is m ixture had the follow ing com position:
P e r c e n t.
C arb o n d io x id e ... 0 .0 3 O x y g e n ... 13.00 M e th a n e ... 9 .4 0 N itro g e n ... 7 7 .5 7
T he m ixture was placed in a cy lin d rica l vessel having a ca p a city of 2750 cc. T w o cop p er terminals were qu ickly broken to produce-the flash, w h ich took place in the center of the vessel. A curren t of 7.5 amperes a t a pressure of 220 vo lts w as used. A flash about one-half inch long could be obtained. On the break of the contact the inflam m ation spread upward almost to the top of th e jar.
W i t h 1 5 .x p ercen t, o xyg en and 9 .4 p er cent, methane, a quite violent explosion w as obtain ed under the same conditions of experim entation. E xperim ents were also performed in w hich a sm all one-eighth inch spark from an induction coil w as used as th e source of igni' tion. A m ixture h aving the follow ing c o m p o s itio n
exp lod ed :
P e r cent.
C arbon d io x id e ... 3 .9 2 O x y g e n ... 16.25 M e th a n e ... 9 .4 3 N itro g e n ... 70.3 7
U nder the same conditions a m ixtu re having the follow ing com position in w hich th e o xyg en was slightl}
diminished, did not inflame a t all :
Mar., 1913 T H E J O U R N A L O F 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
P e r c en t.
C arbon d io x id e ... 3 .9 9 O x y g e n ... 1 5 .9 0 M e t h a n e ...'. ... 9 .2 5 N i t r o g e n ...' ... 7 0 .8 6
It was observed in con d u ctin g these ex p lo s ib ility experiments th a t both the electric flash and flam e produced inflam m ation under m ore severe conditions than the small sp ark ; also, a flam e w hen ap plied from below will produce inflam m ation, under more severe conditions, than w hen applied from above.
These are o n ly a few of man}’- experim ents w hich have been m ade on th e e x p lo sib ility of gaseous m ix tures at the B u reau ’s lab orato ry. Som e experim ents have been m ade in w hich b la ck p ow d er has been fired into mixtures of g as an d air, in a g a lle ry h a vin g a capacity of 600 cu bic feet.
Much interest and criticism has follow ed D r. John Harger’s (England) proposal th a t the o xyg en be de
creased and carbon d ioxide be increased in m ines to prevent explosions. B riefly, Dr. H arge r’s proposition is this: A sm all reduction in the o xy g e n p ercen tage and a small increase in th e carbon d ioxide percen tage in mine air will suffice to produce an atm osphere incapable of supportin g com bustion and con seq u en tly an atmosphere in w h ich explosions and gob fires can n ot occur. For average m ines it is suggested to sta rt the experimental w o rk on a large s c a le ; th a t the o xyg en should he reduced to 20 per cent. (i. e., 1 per cent, below normal) and a h alf p er cent. CO , added to it.
Where the conditions w ere more dangerous th e o xygen should be fu rth er reduced, say, to 19 per cen t., and the C02 increased to three-quarters of 1 p er cent.
Time will not be d evoted now to a discussion of the many points in volved in Dr. H arge r’s suggestion, unless it is the wish of the In stitu te. E x p erim e n ts w hich have been perform ed b y th e B ureau, some of w hich are here presented, indicate th a t th e o xyg en percen tage will have to be reduced m uch below th e figures m en
tioned b y Dr. H arger to p reve n t all explosions. O f course, as the o xy g e n percen tage is decreased th e mixture explodes less v io le n tly and less com p letely.
As regards carbon d ioxide, so m uch w ould h a v e to be added to p reve n t fire-dam p explosions th a t it appears th at its use for th a t purpose w ould be en tirely precluded.
M INE-GAS M I X T U R E S C O N T A I N I N G E X P L O S I V E A N D O T H E R P R O P O R T I O N S O F M E T H A N E
Below are g iven som e .analyses of m ine-gas sam ples, some of which contain exp losive proportions of m eth ane. The accom p an yin g carbon dioxide and o xyg en content are of in terest in conn ection w ith foregoing experiments. T h e sam ples w ere collected in m ines wherein ven tilation had been interru p ted fo r som e time. E xplosions had occurred in these mines.
Sample
COo o2 c h 4 n2
8.23 10.50 4 .4 9 76.73
0.4 8 17.49 9 .2 0 72.83
5.81 13.95 5 .07 75.17
1.75 17.63 7 .60 73.02
Q.34 19.46 5 .7 9 74,41
0.35 18.81 7.25 73.59
2.00 15.64 7.37 74.99
Sam ples Nos. 2, 4, 5, 6 and 7 are exp losive. There could be b u t v e ry slight inflam m ation in m ixtures represented b y sam ples Nos. 1 and 3.
K n ow led ge of th e e x p lo sib ility of m ixtu res as th e y o ccu r in mines has been esp ecially useful to th e B u reau in th a t such atm ospheres are fre q u e n tly encountered in exp loration w ork fo llo w in g m ine explosions and fires.
E X T I N C T I O N O F A C E T Y L E N E F L A M E
T h e B u reau has a lrea d y called a tte n tio n to the te n a c ity to existen ce of the acetylen e flam e, in th a t it w ill e x ist in atm ospheres in w hich the ord in ary w ick- fed flam e is extin guished. I t was fou nd th a t a residual atm osphere in w hich an acetylen e flam e had been extin guished contained 11.70 p er cent, o x y g e n and 6.30 per cen t, carbon dioxide. More recent e x p e ri
m ents h ave confirm ed this finding. I t w as also found th a t w hen ab o u t one-half of th e carbon d io xid e w as rem oved as it w as form ed the a ce tyle n e flam e burned in a slig h tly g rea ter o xy g e n deficiency. F o r these experim ents the flam e w as p laced in a g as-tig h t cabinet, h a vin g a c a p a c ity of 25 cu b ic feet. T h e residual atm osphere a fter the flam e had been extin guish ed had the follow in g decom position:
S a m p le fro m m id d le S a m p le fro m b o tto m of c h a m b e r o f c h a m b e r C arb o n d io x id e ... 3 .2 2 3 .1 7 O x y g e n ... 1 0 .9 9 11.1 2
T h e B u reau has observed th a t in mines w hen the o xy g e n has decreased to x i p er cen t., ab o u t 6 p er cent, of carbon dioxide on the a verage w ill be present.
A n o b jection has been raised to th e use of the acetylen e flam e in th a t it becom es extin guish ed o n ly w hen there m ay be g ra ve danger to m en, because of th e presence of m uch b la ck dam p. T h e a cetylen e flame, as is the case w ith other flames, burns less b rig h tly as the prop ortions of o xy g e n in m ine air dim inishes. I t w as observed a t the B u reau ’s lab o rato ry th a t w hen the o xy g e n con ten t of air decreased to ab o u t 16 or 16.5 p er cent, th e flam e resem bled the o rd in ary w ick-fed flam e w hen the la tte r burns in pure air, i. e., air con tain in g 21 p er cent, o xygen . T h is ind ication can be used as a guide again st m en ve n tu rin g into b lack - dam p w orkings contain ing less o xy g e n th an this p ro portion.
E F F E C T O F C A R B O N D I O X I D E O N T H E E X T I N G U I S H M E N T O F T H E F L A M E S O F M I N E R S ’ L A M P S
T h e o rd in ary m iners’ lam p is extin gu ish ed when the o xy g e n falls to ab o u t 16.5 or 17 p er cen t. T his extin guish m en t is alm ost e n tire ly due to th e o xyg en deficiency and not to the carb on dioxide, since this con stitu en t is rarely ever present in sufficient q u a n tity w hen th e o xyg en in m ine air drops to 16 or 17 per cen t., to e x e rt a n y appreciab le effect. W hen a lighted candle w as placed in a bell ja r filled w ith o rd in a ry air it w ent ou t w hen the o xy g e n percen tage fe ll to 16.24 p er cent. T h e carbon d ioxide produced b y the burning am ounted to 2.95 per cent. W hen 3.22 per cent, of carbon dioxide w as origin ally in th e a ir the atm osphere, a fter the extin guish m en t of the flame, contain ed 16.68 p er cent. W hen the atm osphere
T H E J O U R N A L O F 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 M a r . , 1913
o rigin ally contained 13.52 per cent, carbon dioxide and 20.67 Per cent, o xygen the flame w ent out when the o xygen had fallen to 17.39 p er cent. These analyses are tab ulated below:
C om position o f atm o sp h ere C om position of atm o sp h ere a t beg in n in g o f e x p e rim e n t in w hich flam e w e n t o u t
COs 0» COa O2
1... 0 .0 4 2 1 .0 0 2 .9 5 16.34 2 ... 3 .2 2 2 1 .1 3 ‘ 6 .5 1 1 6 .6S 3 ... 13.5 2 2 0 .6 7 16.0 0 17.3 9
It w ill be observed that the initial presence of a large am ount of carbon dioxide had little effect on the flame extinguishm ent. In all of these lab oratory experim ents the flam e prob ab ly existed a trifle longer than w ould be the case in actual m ining practice, because in mines a slight gust of air or sharp thrust of a lam p w ould puff out a dim inishing flame.
E F F E C T O F V IT IA T E D A IR ON T H E L U M IN O S IT Y O F M I X E R S ’ L A M P S
J. S. H aldan e1 recen tly m ade an im portant contri
bution to m ining literature when he determ ined the effect on the ligh t of a sa fe ty lam p w hen burned in atm ospheres deficient in oxygen. Mine air is alw ays deficient in o xygen to some exten t as com pared w ith outside air. T h is deficiency m ay am ount to from o .i to 0.2 p er cent., to 2 or more per cent, under ordi
n a ry w orking conditions.
A table w h ich J. S. H aldane prepared is o f excep tion al interest and is here presented:
Ob s e r v e d Pe r c e n t a g e D n r i x c n o x o f Li g h t w i t h Ob s e r v e d Pe r c e n t a g e D n t t x m o x o r Ox y g e n
L i g h t O x y g e n L i g h t p e r c e n t a g e O x y g e n p e r c e n t a g e g i v e n p e r c e n t a g e d i m i n i s h e d d i m i n i s h e d
IOO 2 0.9s> 0 0.00
90 20 66 10 0 .27
77 20.34 2 5 0 .5 9
¿6 34 1.05
41 ltJ .34 59 1.S9
27 IS. 92 73 2.01
1 1 1 <. 2S S9 > 65
0 IS.01 IOO 2.9 2
Dr. H aldane observed, roughly speaking, th at everv dim inution o: c . i p er cent, in the oxygen caused a dim inution o f 3.5 p er cent, of the value of the light in th e pure air.
S I G H V E L O C IT Y O F A I R C U R R E N T S IN M IN E S
A s against m an y good reasons pu t forth fo r keeping m iners p le n tifu lly supplied w ith fresh air. there has arisen the protest th a t w ith high velocities of air currents in m ines and high o xyg en content of m ine air.
explosions nave increased in num ber. L o w oxvgen content as a pre ventive of explosions has been discussed tn p art in tn is paper: the question of high velocities is more com p letely w rapped up w ith the question of c u st explosions, and w ill no: be discussed here.
AFTER-D AM P
iw o sam ples 01 atter-cam p atm ospheres are here presented. T h e y are o f interest as show ing the large am ount e ; carbon m onoxide (white-dam p) present sh o rtly a fte r an explosion.
t-a m p ie N o. r w a s co i_ected 30 m in u te s a f t e r a n e x p lo s io n h a d o c c u r r e d a t th e E x p e r im e n ta l m in e
1 Cfcffiw- f G uardian. O ctober 25» 1912_
of the B ureau a t B ruceton, Pa. I t w as tak en in the m ain en try a t the jun ction w ith the first righ t b u tt entry after ventilation had been restored in the m ain entry.
Sam ple No. 2 w as collected a t the face of the first right b u tt e n try 100 feet from w here Sam ple No. 1 had been collected. V en tilatio n had n ot been restored in this entry.
S a m p le X o . 1 San^ple X o. 2
C arbon d io x id e 0 .2 6 1 .5 4
O x y g e n ... 2 0 .2 6 1 7 .7 9 C arb o n m o n o x id e .. . 0 .1 6 1 .8 9 M e th a n e ... 0 .1 2 0 .6 5 X itro g e n ... 7 9 .2 0 7 8 .1 3 H y d ro g e n p re s e n t less t h a n 0.20 p e r c e n t.
These analyses are in stru ctive as show ing th at very dangerous atm ospheres m ay exist a fte r an explosion in a mine in close p ro x im ity to atm ospheres wherein men would not soon feel distress. T h e B ureau found th at in o .i 6 per cent, carbon m onoxide a m ouse shows only slight signs of w eakness a t the end of one hour's time. In the same atm osphere a bird showed signs o f distress in 3 m inutes tim e and fell from its perch in
iS minutes.
In exploring a mine contain ing after-d am p a person could, b y disregarding th e w arnin g of a sensitive anim al like a canary, tra v e l in a v e ry sh ort tim e from an atm osphere th at w ould not distress him rapidly into one where collapse w ould q u ic k ly follow .
A U T O M A T IC G A S S A M P L E R
T he Bureau has la te ly developed an autom atic mine g as sam pler to a stage o f com pletion w here it is be
lieved sam ples of after-gases can be trap p ed a t the time an explosive w ave goes b y and a t prearranged intervals thereafter in order th at the ch em istry of th e explosions in the E xperim ental mine m ay be b e tte r studied.
A n analysis of a sam ple collected a t the Altoft E xperim ental station (E ngland) I/ .0 o f a second after the explosion had passed con tain ed th e following constituents:
P e r
c e n ta g e s C arb o n d io x id e ... 11.25 O x y g e n ... 1.15 . C arbon m o n o x id e ... 8 .1 5 H y d ro g e n ... 2 .7 5 M eth a n e ... 2 .9 5 X itro g e n ... 7 3 .7 5
T he high percentage of carbon m onoxide will be noticed. T h e British report calls a tten tio n to the presence of oxygen as show ing th e inrush of air even so short a tim e a fte r the explosion w a v e had passed.
T h ey state that, a t the in stan t o f p assage of the flame, the oxygen should h ave been e n tire lv c o n s u m e d .
The g allery a t A lto ft’s is ab o ve ground, however, and inrush of pure air w ould b e q u ick er th a n in a mine.
D IS T R IB U T IO N O F A F T E R - D A M P
I t is w ell know n to m ining m en th a t a fte r an e.xplo- sion, p arts of a mine m ay b e q u ite unaffected by the explosion, and th at in som e p laces th e products of -tie explosion (white-dam p, etc.) m a v not penetrate.
Men h ave lived for d ays in som e m ines a fte r explosions '“ •■‘I rescued. On the o th er hand, m en rushing into the tra ck of the explosion in th e dash fo r safety have
Mar., 1913 T H E J O U R N A L O F 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
frequently been overcom e. A s is g en era lly recognized, the heaviest toll of life is alm ost in v a ria b ly due to the white-damp and not to exp losive violence.
USE O F B IR D S F O R C O N T I N U E D E X P L O R A T I O N W O R K
The Bureau has m ade experim ents h a vin g to do w ith the use of canaries for continued exp loratio n w ork, having in mind th e fa c t th a t th e sam e anim al m igh t be used and overcom e several tim es in the sam e d ay.
It was found th a t even a fte r rep eated exposures to carbon m onoxide these anim als, upon subsequent exposures, show distress, collapse and re v iv e in ab o u t the same period of tim e as on the first exposure.
Consequently these anim als can be used again and again for all p rac tica l purposes w ith th e know ledge that they will not be less efficient for exp loration w ork even after repeated exposures. N o parallel can be drawn regarding th e effects on m en of carbon m on oxide from these experim ents. Men h ave been m onths recovering from severe cases of poisoning, and the after-effects h ave been v e ry form idab le. T o show how differently carbon m onoxide affects men and animals the follow ing exp erim en ts perform ed b y th e Bureau are here tab u la te d :
Qu a n t i t y o f C O Us e d = 0 . 2 5 Pe r Ce n t. E ffects on C anaries
Time exposed D istre ss C ollapse R e c o v e ry
3 m in u tes 2 m in u te s 3 m in u te s 7 m in u te s
E ffects o n M ic e
Time exposed D istre ss C ollapse R ec o v e ry
12 m inutes 6 m in u te s 12 m in u te s 25 m in u te s
E ficct on M a il
Time exposed D istre ss C ollapse R ec o v e ry
20 m inutes 1 h o u r S h o u rs
Whereas the an im als w ere le ft in th e atm ospheres until they collapsed, the m an le ft the atm osphere experiencing b u t little discom fort a t the end of 20 minutes. One hour la te r he becam e v e ry sick. Much might be w ritten ab o u t th e poisonous a ctio n of carbon monoxide. A fu rth e r discussion w ill be reserved for a Bureau publication.
U S E O F S P A R R O W S F O R R E C O V E R Y W O R K
The Bureau has a ttem p ted to use E n glish sparrow s for recovery w ork in m ines w ith not m uch success, because those so fa r obtained h a ve not su rviv ed captivity. Pigeons are not sensitive enough. A t the end of n m inutes in an atm osphere contain ing
° - 25 per cent, of carbon m onoxide, th e y show ed b u t slight signs of distress. M ice are m ore sluggish and not so easily affected as canaries, b u t a t the sam e tim e, useful. A mouse an d a c a n a ry to g eth er w ould m ake a good com bination. T h e usefulness of sm all anim als for detecting bad a ir in mines has been so w ell recog
nized in England th a t th e y are k e p t a t all m ine sa fe ty stations and som e collieries. T h e B u reau of Mines of this country keeps them a t all of its stations.
IN T R U S IO N o f N A T U R A L G A S I N T O C O A L M I N E S
Natural gas has intruded into som e coal m ines w ith disastrous consequences. M ining m en are alert to the importance of the questions. Old abandon ed w ells are an especial m enace in th a t no b o d y kn ow s the whereabouts of some of them .
Som e com parison b etw een th e e x p lo sib ility of natu ral gas and fire-dam p is interesting. N atu ral gases of the A p p a lach ia n fields co n tain oth er paraffin hydrocarbons than m ethane, p rin cip a lly ethane. The follow in g an alysis show s th e com position of th e n atu ral gas used a t P ittsb u rgh . This g as is draw n largely from W est V irgin ia. Som e com es from W estern P en n sylvan ia.
C arb o n d io x id e ... tra c e (less th a n 0.10 p e r c e n t.) O x y g e n ... 0 .0 0
M e th a n e ... 8 2 .5 E t h a n e ... 1 6 .0 N itro g e n ... 1.5
Carbon m onoxide, hydrogen or eth ylen e are not con tain ed in the gas, n ot even in traces.
B elo w are shown th e exp losive lim its of m ethan e- air m ixtures, and n atu ral gas-air m ixtures. Ign ition w as 'effected b y a sm all electric sp ark from an ind u ction coil.
M e th a n e N a tu r a l g as L o w l im it... 5 .5 0 4 .9 2 H ig h l i m i t ... 1 2 .5 0 1 2 .0 0
B elo w are g iven the ign ition tem p eratu res of m ethane and ethane, determ ined b y D ixo n and C o w a rd :1
M e th a n e ... 6 S 0 ° -7 5 0 ° C.
E t h a n e ... 5 2 0 ° -6 3 0 ° C.
It does not appear from the ab o ve th a t n atu ral g as is so m uch more sensitive to inflam m ation as to p ro duce an added m enace from th is cause upon intrusion into a m ine. T h e g re a t dan ger lies in th e sudden inrush of a large b o d y of inflam m able g a s w hich has n o t a lw ay s been controlled in order to e v e ry disaster.
T h e fa ct th a t carbon m onoxide is not present in the g as is fortu nate. M an y published analyses show n atu ral gas to contain this con stitu en t. T h e sta te m ent is erroneous. H igher paraffin hydrocarbons th an m ethane in n atu ral gas g iv e to the la tte r its ch aracteristic odour.
IN F L A M M A B L E C H A R A C T E R O F T H E G A S E S P R E S E N T I N M I N E A I R
T h e B u reau has alm ost read y for p u b licatio n a report show ing the e x a c t ch aracter of th e inflam m able gases present in m an y sam ples of m ine air. In m an y t e x t books, the statem en t is m ade th a t hydrogen, ethylene, carbon m onoxide, and eth an e m ay be present in mine air under norm al conditions of op era
tio n ; as fa r as the auth ors of these books are concerned, th e y h a ve been justified because occasion ally analyses show ing these constitu ents are reported, although, even so, the b u lk of evid en ce shows them to be of rare occurrence under th e conditions cited. B ecau se of the reported presence of these gases in m ine air the question has, a t tim es, been raised regardin g the a p p li
cation to m ining conditions of experim ents perform ed in the lab o rato ry or testin g galleries, in w hich m ethane or the n early sim ilar n atu ral g as is used. In the B u re a u ’s report, m ine gas sam ples from ab o u t 50 m ines are listed. M ethods of exam in ation are de
scribed. T h e g re a t effect of v e ry sm all errors w hich can h a rd ly be avo id ed in the m an ipulation of m an y form s of gas an alysis ap p aratu s is shown in th a t these
i C hem . N ew s, 9 9 , 139 (1909).
i86 T H E J O U R N A L O F 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 Mar., 1913 sm all errors m ay result in the reporting of one or more
p er cent, of com bustible gases other than m ethane.
Of course, if a careful an alyst reports other com bustible gases than m ethane in even a few samples, then one is justified in believing th at th e y m ay occur in other samples. The above statem ent excep ts a few mines around the oil regions into which natural gas m ay have escaped.
A rather com plete bulletin is also ready h avin g to do w ith m ethods of exam ination of mine and natural gases. A p p aratu s is shown for research w ork, also sim ple m achines th a t can be easily operated a t mines.
Chem ical analyses are the basis from which safety lam ps and other gas indicators are constructed and simple m ethods for these standard tests are desired.
An ab stract from the larger bulletin has also been com pleted which contains only those chem ical ap p aratus suitable for use a t mines.
U S E O F B IR D S A N D M IC E F O R E X P L O R A T IO N P U R P O S E S
A publication has also been prepared containing further w ork regarding the use of canaries and mice.
A short a b stract of these findings is given in the pre
ceding pages.
C O O P E R A T IV E W O R K W IT H IL L IN O IS
In cooperation w ith the S tate of Illinois a large num ber of samples have been collected in th a t state b y N. H. D arton, Geologist of the Bureau. T his has also been done in the anthracite fields of Pennsylvania.
T he results of analyses of these samples are being shaped into a report, and w ill show the com position of the air in m an y different mines in those states.
Mr. D arton also reports interesting findings h avin g to do w ith geological conditions and m ethane libera
tion.
N O R M A L M IN E A IR S A M P L E S
In conjunction w ith G. S. Rice, Chief Mining E n gi
neer of the Bureau, a prelim inary report is being assem bled showing the com position of the mine air in m an y different coal mines, under normal conditions in different p arts of the country. A lm ost all of the d ata has been assem bled for this w ork.
M IN E G A S E S A N D E X P L O S IO N S
Mine gas sam ples h ave also been collected b y min
ing engineers of the B ureau follow ing m any mine explosions. Their significance will be discussed in th e reports of those explosions.
U S E O F G A S O L I N E L O C O M O T IV E S
A large num ber of sam ples were collected h aving to do w ith use of gasoline m otors in mines.
E x h a u s t samples h ave been collected, also samples of the air in the mines where m otors were operated.
Special investigations h ave been m ade for coal opera
tors, inspectors, and m otor m anufacturers at their request. I t seemed best to defer a report for publica
tion, however, until results could be obtained con
necting exh aust gases w ith pow er developed, gasoline consum ption different carbureter arrangem ent, etc.
T h is w ork is in progress and is under the direction of O. P. H ood, Chief M echanical Engineer of the Bureau.
B L A C K -D A M P I N M IN E A IR
E n ou gh date has also been collected for the issuance
of a publication on black-d am p in A m erican mines.
Also one on after-dam p.
M I N E R S ’ C IR C U L A R
A m iners’ circular is bein g prepared, h avin g to do w ith a discussion of mine gases. N o attem p t, of course, is being m ade to replace those m ine gas terms, w ith which miners are m ost fam iliar, such as black- damp, after-dam p, after-gases, fire-dam p, etc., but a circular showing the B u re a u ’s o b servation s on these subjects w ill be published, since in the performance of investigative w ork these nam es m ust, a t times, be replaced b y the chem ical ones. B lack -d am p is still sometimes w ron gfu lly used as m eaning carbon dioxide instead of a m ixture of nitrogen and carb on dioxide.
T he latter usually p lays b u t a sm all p a rt in the com
bustion effects produced b y the m ixture.
The deficiency of oxygen, w hich a lw ay s accompanies excessive proportions of black-dam p , is the main factor in flame extin guishm en t in mines. On the other hand, physiological effects, if produced in men when th ey are in atm ospheres in w h ich lam p s do not burn, are frequ en tly due to the carbon dioxide. This statem ent has reference to atm ospheres in old work
ings, etc., and not those th a t h ave been vitiated by mine fires, explosions, etc., and w herein carbon mon
oxide m ight exist. D ifferent m eanings h ave been attrib uted to the word “ fire-dam p.” T o some it means m ethane, to others an y m ixtu re of m ethane and air.
T h a t other gases than m ethane m ay frequ en tly be present is sometimes stated. Som e perso/is define it as an y inflam m able m ixture of m ethane an d air.
Sufficient data are not a t hand to com p letely de
scribe the constituents present in after-dam p. That the products of incom plete com bustion of methane, coal dust and air can be quite com plex, is shown by w ork already perform ed on single gases and air. This statem ent has reference to th e im m ediate after
products of an explosion. T h e B u reau hopes to se
cure data on this point a t the exp erim en tal mine.
A f t e r a stagnan t mine atm osphere has been c l a r if ie d
of smoke particles and easily soluble gases, and gases th a t irritate, there can rem ain, for a lon£ tim e, a clear atm osphere containing oxygen , carbon dioxide, nitro
gen, m ethane, hydrogen and carbon m onoxide; an atm osphere w ith only the ch aracteristic odor of b u r n t
coal and wood, y e t one th a t can be fa ta l because of the presence of the carbon - m onoxide. O xygen may be present in sufficient q u a n tity to enable a lamp flame to burn fa irly well, 'and a b so lu tely no indication given to an exploring p a rty of th e presence of c a r b o n
m onoxide, although the la tte r m ay be present in sufficient am ount to produce fa ta l results. Deaths have been caused b y men relyin g upon the lam p flame to warn them of carbon m onoxide.
Bu r e a t jo f Mi n e s Pi t t s b u r g h
T H E D E S T R U C T IV E D IS T IL L A T IO N O F S E W A G E SLUDGE B y Au g u s t u s H . Fi s k e a n d Ri c h a r d B . Ea r l e
R eceiv ed N o v e m b er 29, 1912 H f S T O R I C A L
The problem of utilizing sew age sludge divides itself
