Determ ination of the dextrinolytic activity of m alt. L. Fl e t c h e rand J. B. We s t w o o d(J. Inst. Brew., 1931, 37, 470—478).—Starch which has been hitherto used as the substrate for the enzymic reaction has been replaced by a-amylodextrin. 1 c.c. of a 4% aq. extract of ground malt is allowed to act for 1 hr. a t 40° on 70 c.c.
of a 3% aq. solution of a-amylodextrin, buffered to pj± 4-9—5-0 by mixed phosphates. The action is stopped by the addition of 3 c.c. of 2iV-NaOH and the vol. made up to 100 c.c. a t 15-6°. The CuO-re- ducing power is determined gravimetrically on 25 c.c.
of the solution and the dextrinolytic activity expressed as g. of maltose produced by 1 g. of dry malt. In the early stage of the enzymic reaction the ratio of enzyme concentration to the amount of hydrolysis approaches a linear function, and the dextrinolytic activity approaches a const, up to R 13—15. The zone of optimal p u lies between 4-5 and 5-2 and is more sharply defined than with starch as the substrate.
The activity as measured with a-amylodextrin is not definitely related to the value as determined with starch, and, in general, it has about half th a t value.
C. Ra n k e n.
Free acidity of som e Portuguese beers. A. V.
d e Le m o s(Rev. Chim. Pura Appl., 1930, [iii], 5, 38—41).
—The difference between the results obtained by the H and quinhydrone electrodes does not exceed fw 0-07.
The second method is, in general, the more convenient.
H . F . Gi l l b e.
T heory of ethyl alcohol rectification. O. v o n
Ke u s s l e r (Chem.-Ztg., 1931, 55, 669—671).—A crit.
survey is made of the literature dealing with the rectifi
cation of EtO H and the azeotropic mixtures involved.
T. McLa c h l a n.
MeOH and EtOH.—See III.
Pa t e n t s.
Preparation of beer weak in alcohol. A.
Ha s e l b a c h (B.P. 354,766, 12.5.30).—M alt wort pre
pared with approx. double the addition of hops usual with top-fermentation beers is fermented normally with top-fermentation yeast. If desired, wort containing half the amount of malt may be fermented as above, and the second half of the malt or a sugar solution added at the close of the fermentation. C. Ra n k e n.
Sterilisation of beer. Be r n d o r f e r Me t a l l w a r e n- f a b r. A. Kr u i t A.-G. ( B .P . 355,010, 7.8.30. Austr., 10.7.30).—Beer is heated to approx. 100° for 1—2 sec.
by passing it a t 10—15 atm. pressure between heated surfaces which are not more than 1 mm. apart and are coated with or composed of Ag, Ni, or other metal having germicidal power. The sterilised beer is cooled by passage through the preheater. C. Ra n k e n.
Abs. EtOH.—See III. Water for brewing.—See X X III.
XIX.— FOODS.
T esting the colour of flour. R . Ru t e r(Miihlenlab., 1931, No. 2, 9—13).—Errors in comparing the colours of flour samples arise through variations in compression, fineness, moisture content, and incidence of the light.
T h e s e f a c t o r s a ls o a f f e c t t h e c o m p a r is o n o f t h e m o is te n e d s a m p le s , o w in g t o v a r ia ti o n s i n t h e t h ic k n e s s o f t h e t r a n s l u c e n t d o u g h la y e r . B e t t e r r e s u l ts a r e o b t a i n e d b y c o m p a r in g d o u g h s p r e p a r e d f r o m t h e s a m p le s , b u t t h e b e s t c r it e r i o n is t h e c o lo u r o f t h e b r e a d c r u m b , a s t h i s t a k e s i n t o a c c o u n t n o t o n ly t h e c o lo u r o f t h e flo u r, b u t a ls o i t s b a k in g q u a litie s . W. J. Bo y d.
Colloid chem istry of acid gluten solutions. E.
Be r l i n e r (Miihlenlab., 1931, No. 2, 13—14).—The deductions and methods of Ruemele relating to gluten evaluation (B ., 1931, 737, 943) are criticised.
W. J. Bo y d.
Soft curd m ilk. R. L. Hi l l (Utah Agrie. Exp. Sta.
Bull., 1931, No. 227, 24 pp.).—Softness of milk curd (cf. author’s test, J. Dairy Sci., 1923, 6 , 509) is charac
teristic of the cow and, except for drastic changes, independent of the nature of the ration. The curd tends to harden in the later stages of the lactation period. Removal of the fat from milk produces a harder curd, whereas prolonged heating as in the manu
facture of evaporated milk has a softening effect. Soft curd milk « 20 g. tension by the Hill test) is digested by delicate infants without dilution. Hard curd milk is preferred for cheese-making. A. G. Po l l a r d.
Determ ination of keeping quality of m ilk.
I. Methods of com parison. II. Observations in sextuplícate. III. Observations at different temperatures and at successive intervals on the sam e sam ple. A. H. Ro b e r t s o n (Vermont Agrie.
Exp. Sta. Bulls., 1930, No. 314, 46 pp. ; No. 315, 39 pp. ; and No. 316, 55 pp.).—I . [With J. M. Fr a y e r.] The keeping quality of milk as judged by the increase in bacterial numbers from the time of sampling until souring is better based on the geometric than on the arithmetic mean of the counts. When used as an index of the keeping quality the logarithmic val. of plate counts is preferred as showing less variation. The plate-count method is more accurate than the methylene-blue test for samples of low bacterial content, but inferior for highly bacterial milks.
II. [With R . I. Mo o d yand J. M . Fr a y e r.] Numerous comparisons of plate-count with methylene-blue tests are recorded.
I I I . [With J. M. Fr a y e r.] The various tests of keeping quality are fairly consistent for samples stored at 21—27°. At lower temps, the methylene-blue tests show wider variations than the plate counts.
A. G. Po l l a r d.
Exam ination of com m ercial egg-yolk. R. F.
In n e s (J. Soc. Leather Trades’ Chem., 1931, 15 , 434—
438).—Fresh egg-yolk, 3 commercial samples, and a synthetic egg-yolk were analysed for loss in wt. at 105°, light petroleum extract, ash, NaCl, N, P , and emulsifi- ability on adding 1 drop to 5 c.c. of H 20. The results for one commercial sample and for the fresh egg-yolk were similar, but the former gave the higher ash and NaCl contents. The light petroleum extract of another commercial sample was high and the N and P contents were low ; the unsaponifiable m atter in the oil was also low and a poor emulsion was obtained in H 20. Greasy leather resulted from its use, and it was concluded th a t some animal oil had been mixed in with the product.
'cat A b s tr a c ts— B .
/ I ______________ Cl. X I X . — Fo o d s.
emulsion in H20 was obtained with the synthetic egg-yolk. The figures for the third commercial sample were normal. A spue scraped from leather treated with it was found to be a mixture of palmitic and stearic acids, the development of which could not be ascribed directly to the sample. D. Wo o d r o f f e.
Chemical changes in the fat of frozen and chilled m eat. III. Bacon. C. H. Le a (J.S.C.I., 1931, 50, 343—349 t).—The free acidity values observed in the fat of tank-cured bacon during storage at —10° for periods up to 152 days, followed by hanging a t 15° for 18 days, gave no indication of attack by micro-organisms on the fat, nor were any signs of tainted flavour observed which might have been attributed to this cause. The superficial fat of freshly cured bacon was found to con
tain small quantities of active 0 of the order of 2—7 c.c.
(as 0 • 002AT-Na|S20 3 solution per g.) which rendered the fat very susceptible to further oxidation during storage.
When stored at —10° the exposed surface of the fat oxid
ised comparatively rapidly, reaching active 0 contents of 30—60 c.c. in 152 days, without, however, developing any appreciable yellow colour. At 15°, on the other hand, the bacon became yellow on the surface, and (after cold storage) sometimes in the interior of the fat. On cooking, the oxidised portions of the fat had an unpleasant rancid flavour. The effect of smoking on bacon after storage a t —10° was to arrest the progress of superficial oxidation for a period, and there is some evidence th a t oxidation in the interior of the fat may also be somewhat retarded.
So far as could be ascertained, rapid cooling of the carcases of pork at 5° prior to curing had no appreciable effect on the fat. The addition of cod-liver oil in small quantities to the diet of the pigs up to the time of slaughter was without effect on the I val. of the fat of the bacon, but appeared to have a somewhat adverse effect on its keeping properties.
H oney investigations. E. F. Ph i l l i p s (J. Econ.
Entom., 1931, 24, 581—589).—A review of the problems involved in the preparation of honey for marketing.
The need of wider examination of the physical properties of honey is emphasised. A. G. Po l l a r d.
Crystallisation of honey. E. J. Dy c e (J. Econ.
Entom., 1931, 24, 597—602).—The quality of cryst.
honey is highest when the crystals are small. Crystal growth and the factors and method of controlling fine crystallisation are discussed. A. G. Po l l a r d
Effect of temperature on honey in storage.
H. F. Wil s o n and G. E. Ma r v i n (J. Econ. Entom., 1931, 24 , 589—597).—Honey may be stored below 11° without change of colour or flavour. Storage at 11—18° involves greater risk of fermentation than at higher or lower temps. At 26-6° colour change and risk of fermentation are small. From 26-6° to 38°
fermentation is unlikely, but the colour is affected.
The possibility of the partial bleaching of honey by sunlight is noted. A. G. Po l l a r d.
M oisture determ ination in honey by m eans of the refractom eter and the vacuum drying oven.
G. E. Ma r v in and H. F. Wi l s o n (J. Econ. Entom., 1931, 24, 603—604).—The sand-bath method is of doubtful accuracy and gives results consistently 2—2|%
lower than those by the refractometer method. There is a fairly uniform gradation between the results of the above and the glass-plate, blotting-paper, and asbestos
methods. A. G . Po l l a r d.
T reatm ent of soya beans for hum an consum p
tion. M. K rajcin ov ic (Arh. Hemiju, 1931,5, 239—242).
—The amount of substance extracted by II20 from the raw beans increases with the acidity of the I I 20 from 2 • 5% for ordinary H 20 to 8 • 9% for 0 • 5% HC1. Alkaline extraction is unsuitable. The digestion coeff. is increased by the above treatment. R. Truszkowski.
Effects of acetylene on the ripening processes of bananas. R. Ha r t s h o r n (Plant Physiol., 1931, 6, 467—484).—Treatment with C 2H 2 accelerated the ripening process, as shown by the rates of softening, respiration, and of starch hydrolysis, and by changes in colour and flavour. A. G . Po l l a r d.
Vitam ins in canned foods. X I. A canned food diet. E . F . Ko h m a n, W. H . Ed d y, and C. Z. Gu r i n
(Ind. Eng. Chem., 1931, 23, 1064—1066 ; cf. B ., 1931, 944).—Rats and guinea-pigs fed on a diet consisting wholly of canned foods (sterilised by heat) show normal reproduction in the fifth and third generations, respect
ively. The rate of growth (and wt. at maturity) is higher than th a t reported as normal. II. Bu r t o n.
Salm on oil and canned salm on as sources of vita m in -/l and -D. C. D . To l l e and E. M . Ne l s o n
(Ind. Eng. Chem., 1931, 23, 1066—1069).—The oil recovered from canned salmon contains as much vitamin- D as does cod-liver o il; little vitamin-.^ is present. Oils produced from the offal contain much vitamin-/), but the vitamin-J. content varies appreciably. Commercial oils show considerable variations in their vitamin contents ; the amount of -D is usually of the same order as in cod-liver oil. H. Bu r t o n.
Industrial w astes.—See XVI and X X III.
Pa t e n t s.
Production of a m ilk preparation. W. R. B.
St. J. Ga t e s, J. Ta v r o g e s, and Cow & Ga t e, Lt d. ( B .P . 354,917, 11.6.30).—Milk powder is mixed with sugar, milk is added, and the whole is evaporated with continuous stirring under vac. The product, after being moulded and cooled, has 10—15% of moisture.
E . B . Hu g h e s.
T reatm ent of natural or artificial cream . B . Bo r t h e n ( B .P . 355,611, 29.11.30. Nor., 29.11.29).—
Cream is treated in homogenisers a t different temps., first above the m.p. of the emulsified fat, then below this point, whereby the consistency and flavour of the cream are improved. H. Ro y a l- Da w s o n.
T reatm ent of tea and coffee. H . Mu c h (B.P.
354,771, 5.5.30).—I t is claimed th a t in tea and coffee the properties considered harmful are rendered ineffective by first treating the dry substance with “ lipoid tannic acids” (prep, described). E. B. Hu g h e s.
Im proving the taste of, and rem oving poisonous m atter from , infusions of tea and coffee. W.
St e l k e n s ( B .P . 354,942, 1.7.30. Ger., 2.7.29).—Unde
sirable flavours are removed from tea and coffee infusions
B r itis h C h e m ic a l A b s tr a c ts —B .
C l. X X.— Me d i c i n a l Su b s t a n c e s ; Es s e n t i a l Oi l s. 9 9 3
by mixing the dry substance with activated C or H 2SiOa before preparing the drink, with or without H20-sol.
substances such as glycerin or sugar. E. B. Hu g h e s.
Jelly preparation. Ca l if o r n ia Fr u it Gr o w e r s’ Ex c h a n g e (B.P. 355,130, 11.11.30. U.S., 12.11.29).—
Pectin is mixed with a material which will liberate a free edible acid on boiling, such as acid anhydrides, acid chlorides, esters, compounds of the type of glycero- triphosphoric acids, K chloroacetate, etc. The dis
advantages of prejellation and lumpiness of the jelly are thus avoided, a correct pn is ensured, and risk of deterioration of the pectin on keeping removed.
E . B. Hu g h e s.
Roasting oven. P rocessing apparatus [for m ilk ].
—See I. Air for food preservation.—See XI.
XX.— MEDICINAL SUBSTANCES ; ESSENTIAL OILS.
T esting of pharmaceutical hydrogen peroxide.
R. A. Di n i s (Rev. Cliim. Pura Appl., 1 9 3 0 , 5 , [iii],
1 0 6 — 1 2 1 ).—Methods are described in detail.
H . F. Gi l l b e.
Extraction as applied to N.F. [National Form u
lary] preparations. E. Gu t h and H. A. La n g e n h a n
(J. Amer. Pharm. Assoc., 1931, 20, 746—754).—The total extractive, the % of total extractive extracted under varying conditions, and attem pts to measure the amount of swelling occurring when various vegetable drugs are treated with alcoholic menstrua of different EtOH concentrations are described. Drugs containing measurable constituents (jalap and 'nux vomica) have been similarly examined, and the composition and uses of the alcoholic menstrua of the U.S.P. and N.F. are
discussed. E. H. Sh a r p l e s,
Decom position and preservation of fluid extracts of ergot, D .A .B. VI. H. Oe t t e l (Arch. exp. Path.
Pharm., 1931, 161, 359—367).—The extracts may lose over half their activity within 1 year, but a drier preparation made by the Krause method from an extract, D.A.B. VI, retained its activity intact on
keeping. W. 0. Ke r m a c k.
Cantharidin from M y la b r is p u s tu la ta , Fb., India. B. H. Iy e r and P. C. Gu h a ( J . Indian Inst.
Sci., 1931, 14A, 31—39).—The adult beetles are col
lected by hand, killed with CHC13, sun-dried, and preserved whole or powdered. For free cantharidin the powder is extracted with CHC13, the fats being removed from the CHC13 extract by CS2. Cantharidin is crystall
ised from EtOH (m.p. 218°; yield 1-35%). For total cantharidin 100 g. of powder are treated with 150 g. of EtOAc and 2 g. of H 2S04, after 48 hr. 4 g. of BaCOs are added, and the mixture is extracted for 48 hr. with EtOAc. After removal of the solvent, the Tesidue is macerated several times with cold light petroleum and the crude cantharidin treated with a small quantity of hot EtOH (yield 2-3%). Cantharidin is slowly vola
tilised. Cantharidinhydrazide, C10H14O3N2, m.p. 118°, prepared by treating an alcoholic solution of cantharidin with an excess of hydrazine hydrate at 0° and allowing the temp, to rise to th a t of the room, on treatm ent with PhCHO in aq. solution at 100° for \ hr. forms a benzylideiie derivative, C^HjgOgN^ m.p. 158°.
C. C. N. Va s s.
A ssay of tablets of resin of P o d o p h y llu m . L. E.
Wa r r e n (J. Assoc. Off. Agric. Chem., 1931, 14, 380—
386 ; cf. B., 1930, 393).—The powdered tablets arc mixed with sand (13 times wt. of resin) and exhausted by percolation with EtOH, followed by hot continuous extraction with a fresh supply of the same solvent. An aliquot portion of the tincture is treated with 0-6% IIC1 and repeatedly extracted with equal vols. of CHC13.
The CHC13 is washed with 0-6% 1IC1, which is again extracted with CHC13. The combined CHC13 extracts are evaporated to dryness, 1 c.c. of EtOH is added, and the whole again taken to dryness. T. McLa c h l a n.
Determ ination of m ercury in preparations and m ixtures. G . We is s m a n n (Pharm. Zentr., 1931, 72, 561—565).—The prep., after destruction of org.
matter if necessary, is heated with H 20, HC1, and N aII2P 0 2, and the ppt. is filtered off, washed free from Cl', dissolved in H N 03, KMn04 added, decolorised with FeS04, and titrated with 0 • 1/V-NH4CNS. Many org.
substances need no preliminary destruction of org.
matter, but give metallic Hg on treatment with NaH2P 0 2. Modifications of the method for the deter
mination of Hg in medicinal preps, are given.
E. H. Sh a r p l e s.
Sesquiterpenes. I. Sesquiterpene and sesq u i
terpene alcohol from Japanese cam phor oil.
S. Ko m a t s u, H. Fu jim o t o, and S. Ta n a k a (Mem. Coll.
Sci. Kyoto, 1931, A, 14, 149—171).—The sesquiterpene, which probably exists as (I) in the oil, is isolated from the high-boiling fraction as a mixture, b.p. 119—
127°/8 mm., [oc]D +16-2° to + 17-3°; isomerisation (migration of double linking into ring) occurs during distillation over Na. The sesquiterpene is unaffected by
Na and amyl
?.^2 .. 2 a lc o h o l, is
y C \y C H 2\ dehydrogen
-~~ — CH2 CH2 CH CH2 ated by S at
I | | | 180—200° to
JH 2 CH CHMe cadalene, is
\ c / \ D H a/ oxidised by
I X)H KMnO in
CH, CH
CH„ CH CHMe
CMe,
(I) CHMe2 (II) f l ;
totsophthalic acid, by Mn02 and H 2S04 to prehnitic acid, and by 0 3 in CHC13 to CH20, formic acid, an aldehyde, and a diketone Cn H140 2, b.p. 100—110°/4 mm. (semicarbazone.
m.p. 219°). The alcohol (II), b.p. 157—160°/12 mm., [a]D +35-5°, isolated through the Na salt from the oil (fraction b.p. 140—180°/12 mm.), is dehydrogenated by S a t 180—230° to cadalene, and reduced catalytically (Pd) in AcOH at 40—50° to the corresponding saturated alcohol (III), b.p. 145—150°/12 mm„ [a]D + 7-5°.
Reduction of (II) with H2 and Ni at 150—160°/80 atm.
also gives (III) (with b.p. 160—168°/19 mm., [ajD -f-16 • 6° to + 20 • 7°), which is dehydrated by Japanese acid clay to a hydrocarbon (IV), CLr,H26, b.p. 138—140°/20 mm.
(IV) and 0 3 in CC14 give C0Me2 and a product, reduced by Na and EtOH to an alcohol C12H 220, b.p. 120—130°/4 mm., [o c ] d —7 -2° (dehydrated to a hydrocarbon C ^H ^, b.p. 145—155°/25 mm.). Oxidation of (II) with alkaline KMn04 gives oxalic and 3-methyladipic acids, whilst with 0 3 in CC14, CH20, formic acid, and a keto- alcohol, C14H 240 2, are produced. Reduction of this
B r itis h C h em ica l A b s tr a c ts —B .
994 Cl. X X I.—Ph o t o g r a p h i c Ma t e r i a l s a n d Pr o c e s s e s. C l. X X II.— Ex p l o s i v e s ; Ma t c h e s.
keto-alcohol with Na and EtO H affords an alcohol C^IIogO, b.p. 137—140°/5 mm., dehydrated to a hydrocarbon C14H 24, b.p. 143—145°/30 mm. (ozonolysis products, COMe2 and a compound C14H 240 3). Dehydra
tion of (II) with AcoO a t 150—160° gives a hydrocarbon C |H 24, b.p. 136—142°/16 mm., [a]D +51-4° [additive compound with Hg(0Ac)2 ; ozonolysis products, CH20, formic acid, and a compound C14H220 4 (semicarbazone, m.p. 63—65°)], whilst with Japanese acid clay a mixture of hydrocarbons C ^H ^, b.p. 131—134°/14 mm., [a]i>
+ 2 2 '1° [ozonolysis products, C0Me2 and a compound c 12h m0 4 (semicarbazone, m.p. 55—57°)], and b.p. 137—
140°/14 mm., [<x]d —23-7° (ozonolysis products, C0Me2 and a compound CjjH-^Og), is produced. (II) is dehydrated by phenylearbimide to a hydrocarbon C15H24, b.p. 134—139°/18 mm., [oc]D +46-6° [dihydro- chloride; additive compound with HgtOAc)^, oxidised by 0 3 to a substance (semicarbazone, m.p. 90—93°).
Alternative formulae are suggested for these hydro
carbons. H. Bu r t o n.
Fatty acids from cantharis oil.—See X II. Pyre- thrum extracts.—See X X III.
Pa t e n t s.
Rem edies for com bating diseases. C. F. Ch a r l t o n (B.P. 355,435, 2.7.30).—The omentum or mesentery of a pig or other mammal is ground and extracted with aq. EtOH. The extract is standardised by dilution with NaCl solution followed by a determination of its action in dissolving red blood cells. For hypodermic injection the EtOH is removed and replaced by H 20.
E. H . Sh a r p l e s.
Dental cem ent.—See IX . Air for therapeutic purposes.—See XI.
XXI.—PHOTOGRAPHIC MATERIALS AND PROCESSES.
The photographic em u lsio n : after-ripening.
B. H . C a r r o l l and D. H u b b a r d (Bur. Stand. J. Res., 1931, 7 , 219—259).—-The changes in sensitivity which occur after washing the emulsions (“ after-ripening ” ) and the effects produced by eight variables are discussed.
The amount of after-ripening depends on the extent to which sensitivity nuclei have been formed during ripen
ing. The influences of temp., and of bromide, chloride, and [ H ‘], are in agreement with predictions of the chemical reactions forming sensitivity nuclei. Experi
ments with different kinds of gelatin have been conducted;
the gelatin/Ag halide effect can be explained by its influence on the rate of development. An increasing % of Agl leads to an increased practicable after-ripening.
After-ripening during storage is discussed. Chemical analysis shows th a t there is an increase in non-halide Ag ; the non-halide Ag is photographically inert.
W. R. An g u s.
Developm ent of the solarised latent im age.
A. P. H. T r i v e l l i and E. C. J e n s e n ( J . Franklin Inst., 1931, 2 1 2 , 351—367).—The development of such images for pure AgBr emulsions with p-aniinophenol, pyro- gallol, and quinol developer without KBr, and with quinol developers containing 0-002—0-269iV-IvBr, has been investigated. For normal exposures the density is proportional to the logarithm of the KBr
concentration, deviations occurring with extreme expo
sure and development. The proportionality holds only in a limited way for the solarisation region. At the threshold of the first reversal of the solarisation there is no correlation. The tie-point of the solarisation curves moves towards the origin of the distance/log E axes with increasing content of KBr in the developer.
H. J. Em e l e u s. Pa t e n t s.
[M ulti-colour] photographic screens. B. Ga s pIr (B.P. 354,167, 31.1.30. G e r., 2.2.29).—T h e r m o p la s tic t h r e a d s w i t h c o lo u r e d c o r e s a r e w o u n d o n a s p o o l in m a n y l a y e r s . T h e s p o o l is c u t o p e n , f l a t t e n e d o u t, s t r e t c h e d u n d e r h e a t , a n d c u t i n t o s e c tio n s , w h ic h a r e s u p e r i m p o s e d ; t h e t r e a t m e n t is r e p e a t e d t il l a la r g e b lo c k is f o r m e d , f r o m w h ic h t h i n s e c tio n s a r e c u t a n d p r e s s e d o n c a r r i e r s t o f o r m c o lo u r s c r e e n s .
J. Le w k o w i t s c h.
Sensitising photographic em ulsions. Ko d a k, Lt d., Assees. of L . G. S. Br o o k e r ( B .P . 354,264, 3.2.30.
U.S., 2.2.29).—A naphthothiocarbocyanine dye is used to sensitise emulsions beyond 640 m[x. Analogues containing O or Se in place of S may be used.
J. Le w k o w i t s c h.
[Producing m arkings for synchronisation on]
sound and picture film s. I. G. Fa r b e n i n d. A.-G.
(B.P. 354,455, 5.6.30. Ger., 5.6.29).
Fireproofing m aterials.—See VI.
XXII.— EXPLOSIVES; MATCHES.
Distribution of solventthroughoul [nitrocellulose]
powder grains. J. D e s m a r o u x (Mem. Poudres, 1 9 3 0—
1, 2 4 , 1 0 1—1 0 5 ).—The powder consisted of a mixture of CPj and CP2 (N 1 2 - 8 8 % ) , containing 4 0 % of sol. nitro
cellulose, incorporated with E t20 -E t0 H . Samples were prepared by drilling holes of various diameters in portions cut from the cords and removing the outer surface in a lathe so as to give const, thickness. Tests were made (a) on the dried powder and (b) on the powder after steeping a t 8 0 ° for 3 2 hr. When the diameters of the samples were 9—11, 6—8, and 3—5 mm., respectively, the % of EtOH and E t20 were 2 - 6 0 , 5 - 7 3 ; 2 - 6 2 , 6 - 8 9 ; 2 - 5 6 , 6 - 0 4 in the dried powder, and 1 - 1 3 , 4 - 3 8 ;
1 - 4 5 , 5 - 4 6 ; 1 - 5 0 , 4 - 9 0 in the steeped powder. An undrilled sample ( 1 - 5 mm. diam.) contained EtOH
1 - 8 7 % and E t20 5 - 1 3 % . In the steeped samples the amount of EtOH a t the surface was 0 - 6 0 , and of the E t20 0 - 8 5 of th at at the centre. Distribution of solvent does not in any way follow a sinusoidal curve. The diffusion in a thin superficial layer is very slow.
W . J. Wr i g h t.
Determ ination of m oisture in SD powder and SD powder paste. G. A. F l e u r y and L a m b e r t
(Mem. Poudres, 1930—1, 2 4 , 137—145).—Errors in Dupre’s method are due to the difficulty in dete.m'ning the vol. of gas owing to the influence of temp, and pres
sure, occlusion of gas by the carbide, the solubility of
sure, occlusion of gas by the carbide, the solubility of