544
T H E J O U R N A L OF 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 .
No. 5 . made from whole milk modified with whey. When dissolved with the proper proportion of water it has approximately the composition of human milk. No. 6, made from light cream and No. 7 from heavier cream. Nos. 1-7, made from known milks. No. 8 , evidently from whole milk with the addition of cane sugar. No. 9 and No. 10, evidently from skimmed milk with the addition of small amounts of cane sugar. Nos. 8-10 made from unknown milks. MERRELL-SOULE Co., LABORATORY, N. Y..Feb. 17, 1912. SYRACUSE.
A MODIFICATION OF THE BABCOCK TEST AS APPLIED TO THE ESTIMATION O F FAT I N DESICCATED MILK. By N. GREGORY REDMOND. As the Babcock method is the one most generally used by dairymen and manufacturers using milk products, either it or some equally unsuitable method is often applied t o determine t h e fat in desiccated milk. Van Slyke’ appreciates the fact t h a t the ordinary Babcock method, when used with milk powder, gives results which are too low. It occurred t o the writer t h a t it would be a n advantage if the Babcock test could be so modified t h a t it would give accurate results. This modification was finally worked out, and has been successfully used for several months. To test the accuracy of the method, the fat was determined on a sample of desiccated milk by several different methods. One of those used was the Werner-Schmidt method. That this method is trustworthy has been shown by H. D. Richmond2 and also by a n abstract in The Analyst of a recent paper by A. BurrS on the “Composition of Dried Milk Powder.” The results which are shown in the table prove t h a t the direct extraction of t h e milk powder with anhydrous ether gives results which are too low. I n each case where a direct extraction was made, the powder was first dried a t g o o C. t o IOOO C. for a t least five hours. I n using the Werner-Schmidt method the fat was redissolved in petroleum ether and a n allowance made for any impurities. This was also done with the direct extractions when the fat appeared to be impure. I n the ordinary Babcock test, the powder was weighed and transferred t o the test bottle, then dissolved in warm water, cooled, and concentrated sulphuric acid added. This prevents any error whi h might occur from inaccurate sampling by measuring a n aliquot part of a IO per cent. or 20 per cent. solution. The general experience of this laboratory has been t h a t this method is about 3 per cent. low. The accuracy of the new method is shown by the fact t h a t the average of ten determinations by the various methods (excluding the direct extraction with ether distilled over sodium and the ordinary Babcock method) is 28.49 per cent. fat, and the average of four determinations by the new method is 2 8 . 6 2 per cent. fat. A determination in duplicate by the new method can easily be made in less than one hour. Some of its advantages are cheapness, simplicity, speed and accuracy. The following is a description of the method: Weigh 2.5 grams of milk powder and transfer i t to an ordinary Babcock milk bottle, graduated to IO per cent. A glass funnel (about 2” in diameter and with the stem cut off t o %”) is inserted in the neck of the bottle and is of great help in transferring the powder. Add 31 cc. of dilute sulphuric acid (395 cc. concentrated H2S04diluted to I liter) and place the bottle upright in a dish of gently boiling water. Shake frequently and keep in the boiling water until all the powder is dissolved and the solution is dark brown in color. This usually takes from 7 t o IO minutes. After removing the bottle from the
’ “Modern Methods of Testing Milk and Milk Products.” 1906, Ed., p.
86.
a The Analyst. Si, No. 364. pp. 218-224. a Ibid., 86. No. 423, p. 279.
July,
1912
water add 12 cc. concentrated H2S04 (sp. gr. I .82-I .83) and mix thoroughly, taking care to keep the solution out of the neck of the bottle. Agitate with a rotary motion. Place the bottle in a centrifuge and whirl for 4 or 5 minutes. Add hot water until the solution reaches the lower end of the neck, whirl again for I minute, then.add hot water until the fat rises. Whirl again for I minute. I n order to secure accurate results, the fat column must be read a t a temperature not above 140’ F. nor below 130’ F; by setting the bottle in water, the desired temperature may be reached. Readings should be made t o o .05 on the bottle. The reading multiplied by 7 . 2 gives the percentage of fat. ’ 2.5 grams : 18 grams = Reading : X. If reading = 4.00, then 2.5 : 18 = 4.00 : X. I8 O r X = 4.00 X - = 4.00 X 7 . 2 or X = 28.80 per cent. 2.5
A COMPARISONOF DIFFERENTMETHODS
OF
DETERMINING FATIN MILK
POWDER. Fat. Per cent. Squibb’s ether-16
hours’ direct extraction. . . . . . 2 8 . 3 0
Ether containing 5 cc. HzO per liter, 16 hours’ direct extraction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ether containing 5 cc. H20 per liter, 18 hours’ direct extraction.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ether containing 5 cc. H20 per liter, WernerSchmidt method.. ........................... Anhydrous ether (distilled over sodium), WernerSchmidt method.. ........................... Average of ten determinations above. . . . . . . . . . . . By the proposed new method. ...................
Anhydrous ether (distilled over sodium). 16 hours’ direct extraction. Babcock method.. .............................
............................
1
28.45 28.50 2 8 . 5 5 t! 28.50 28.60 28.50 28.56 28.39 1 28,54J
I 1
Averages. 28.37 28.52 28.55 28.53 28.46 28.49
1
28.801 28.44 28.44 I 28.80) 13.55 13.40 25.20 25.201
1
2 8 , 62
13 , 4 7
25.20
Babcock bottles vary in volume. It is more convenient to use bottles which hold at least 45 cc. of water when filled to the lower end of the neck. The bottle should be thoroughly cleaned, rinsed with alcohol and dried (to prevent powder sticking in the neck) before using. This insures clear and accurate readings. Commercial sulphuric acid has been used in making the dilute H,SO, solution and good results were obtained. It is better, however, t o use c. p. acid and thus avoid contamination of the fat column by impurities in the acid. LABORATORY, MERRELL-SOULECo., SYRACUSE, N. Y.,Feb. 17, 1912.
ALUNDUM NOT CONSTANT I N WEIGHT. B Y E. B. FORBES. The invention of porous earthenware laboratory utensils immediately satisfied a large number of urgent and long-standing requirements. As is inevitable under such circumstances this new ware has been put to some uses which it is not adapted to serve, and a correct appreciation of its very great value in the laboratory requires that we search out and recognize its limitations. I n a n effort to shorten and improve upon the usual method for crude fiber determination, we followed the Morgan P. Sweeney mpdification except that instead of straining through an unstandardized cloth we conducted our filtration, washing and ignition all without transfer, in an alundum extraction capsule. It appeared to be a beautiful method, and through the substitution of a n efficient, standardized filter for the rag strainer it seemed to remove from this very unscientific determination one of the principal grounds for our objections; but things were not as they seemed. Alundum is not constant in weight through treatment with water and heat.
July,
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G CHEAPISTRY.
1912
TABLEI.-EFFECTS OF HEATAND WATERON WEIGHTOF
1
2 3 4
ALUNDUM.
.
.-0
11.3179 11.3136 13.1128 13.1098 13.0326 13.0292 11,5042 11.5014
11.3180 13.1130 13.0326 11.5044
4 . 3 -3 .O -3.4 -2.8
11.3180 13.1130 12.0326 11.5044
11.3146 13.1108 13.0310 11.5032
-3.4 -2.2 -1.6 -1.2
+1.0 +1.0 +1.8 +1.8
Table I scts forth results of a test with four alundum extraction capsules. They were washed with water, dried at 100' for 2 hours, weighed, burned in a muffle and weighed again. In all weighings the capsules were contained in glass weighing bottles where they had been placed while as hot as they could be without breaking the glass. The weighing bottles were dried with the capsules in the oven and were kept in desiccators over sulphuric acid. The weight after firing showed that all of the capsules had lost in weight, the amounts varying from 2.8-4.3 mg. Perhaps they were not dry. We then washed with water and lengthened the drying to 3 hours at IOO', weighed, dried 2 hours more at 100' and weighed again. There was no change in weight between dryings, but when fired all lost in weight from 1.2-3.4 mg.; and what is more, the capsules did not return to the weight obtained after the first firing but during this second test gained 1.0-1.8 mg. TABLE IL-EFFECTS OF HEATAND WATERON WEIGHTOF ALUNDUM.
.-c
.-fi .-
q
'a& .* 1 2 3 4 5 6 7 8
11.3160 11.3160 13.1128 13.1128 13.0326 13.0326 11.5044 11.5044 10.2566 10.2566 13.4062 13.4062 11.7162 11;7162 10.8086 10.8086
11.3138 13.1102 13.0309 11.5026 10.2544 13 ,4040 11.7146 10.8070
-2.2 -2.6 -1.7 -1.8 -2.2 -2.2 -1.6 -1.6
11.3164 13.1116 13 ,0340 11.5036 10.2566 13.4066 11.7166 10.8092
11.3136 13.1096 13.0306 11.4996 10.2530 13.4028 11.7142 10.8060
-2.8 -0.2 -2.0 -0.6 ---3.4 -0.3 4 . 0 -3.0 -3.6 -1.4 --3.8 -1.2 -2.4 -0.4 ---3.2 -1.0
We then added four more capsules to the test (Table 11), washed with water, dried for 3 hours at IIO', weighed, dried for three more hours a t IZO', weighed, fired and weighed again. Between dryings the weights were absolutely constant, but on firing we got a loss of 1.6-2.6 mg. Ncxt we washed in water, dried for 31/2 hours at 16o0, weighed, ignited and weighed. This time there was as before TABLEIII.--EFFECTS
OF
HEATON WEIGHT OF
ALUNDUM.
.-a
M
.*2 d $z
71 1 pi,
GZ
3
3 .g Y
'aM I c1
11.3136 13.1096 13.0306 11.4996 10.2530 13.4028 11.7142 10.8060
11.3142 13.1110 13.0312' 11.5008 10.2538 13.4043 11.7144 10.8064
+0.6 f1.4 +0.6 f1.2 +0.8 +1.5 +0.2 +0.4
11.3174 13.1144 13.0354 11.5046 10.2564 13.4082 11.7180 10.8101
4-3.2 +3.4 +4.2 +3.8 +2.6 +3.9 +3.6 +3.7
11.3172 13.1140 13,0350 11.5038 10.2566 13.4078 11.7178 10.8095
-0.2 -0.4 -4.4 4 . 8 +0.2 4 . 4 -0.2 4 . 6
545
a loss in each case from 2.0-4.0 mg. and this last weight as compared with the one after the previous ignition shov&d in each case a n appreciable loss. One point had become clear. Water combines chemically with some constituent of the alundum capsule, a combination which is not broken up a t 160' but which is destroyed at a temperature considerably below 1000'. To throw more light on the apparent change in the weight of the capsule aside from that caused by the hydrating and dehydrating process above referred to, we subjected the same eight capsules to three consecutive firings and meighings without treatment with water. The weights are set down in Table 111. I n the first firing the capsules gained 0 . 2 - 1 . 5 mg., in the second from 2.6-4.2 mg. more, and in the third firing one capsule gained 0.2 mg. while the rest lost 0.2-0.8 mg. Thus aside from the change in weight due to the taking up and loss of water there seems to have been operative a second factor resulting in a gain in weight which partially compensated for the losses occasioned as above mentioned, this gain not reaching its limit, under conditions existing in the muffle, until the second firing after the tests reported in Tables I and 11. The reddish yellow color of the alundum became much lighter during these tests, perhaps due to change in the condition of the 0.5 per cent. of iron contained therein. OHIO
AGRICULTURAL EXPERIMENT February 19, 1912.
STATION.
THE CENTENARY OF THE INTRODUCTION OF GAS. The Centenary of the Introduction of Gas was celebrated in Philadelphia on Thursday and Friday, April 18th and 19th, according to the program published in the April issue of THIS JOURNAL, p. 309. The addresses are now appearing in full in the American Gas Light ,lourtial and in the i'uoceedirigs of the .4nierica?z Gas 111stitute. A limited edition is also being printed in book form; 180 pages, illustrated. Price, $2.00. Copies should be ordered at once of the American Gas Institute, 29 West 39th St., New York City. Brief abstracts of the five addresses follow: By-products in Gas Manufacture. By CHARLES E. MUNROE, Professor of Chemistry a t George XVashington University. Professor Munroe's address gave a n excellent review of the scope and influence of the gas industry since i t took up not only the real by-products of gas manufacture, but the subsidiary products which are often those of allied industries. Among the subsidiary products were mentioned dyes, explosives, flavoring materials, perfumes, synthetic drugs, sweetening principles and photographic developers-all obtained from the by-product, coal-tar, while n-ater-gas tar yields light oils of the benzole series, creosoting oils, naphthalene oils, road compounds and pitches. The U. S. Bureau of Mines has taken up the study of the entirely unknown constitution of coals in connection with the work they are doing toward the more complete and economic development of our fuel resources. The by-products of the coal gas industry are coke, gas, carbon, tar, ammoniacal liquor and spent purifying material, either lime or oxide: in the water gas industry, tar and purifying material with a meager amount of ammoniacal liquor: in the oil gas industry, lampblack, tar and spent purifying material for the new Low process, and "hydrocarbons" for the cracked and compressed oil gases. In the acetylene gas industry calcium hydroxide is practically the only product incidental to the reaction other than the acetylene. The importance of the many varieties of nitrogen and ammoniacal products to the fertilizer industry as well as to thc nation were presented with care, as well as the methods for their
