Apparatus for the Determination of Fat by the ... - ACS Publications


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T H E J O U R N A L OF I N D U S T R T 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

o,ne i n t o t h e o t h e r , t h e conversion curve, which is selfe x p l a n a t o r y , is herewith given, i n a s m u c h as, t o t h e author's knowledge, a c u r v e of this kind, or a table of conversions, is a t present nowhere available. CHEMICAL LABORATORY THEwhi. R A H R SONS' C O . MANITOWOC, WISCONSIN

APPARATUS FOR THE DETERMINATION OF FAT BY THE ROESE-GOTTLIEB METHOD' By WILLIAMBRINSMAID

Wishing t o use t h e Roese-Gottlieb m e t h o d for t h e d e t e r m i n a t i o n of f a t i n e v a p o r a t e d milk a s published i n Circular No. 66 of t h e B u r e a u of C h e m i s t r v . i t was found t h a t t h e - 'Rohrig t u b e s for t h i s purpose could n o t be purchased. None of t h e dealers in chemical glassware of whom inquiries were m a d e , knew a n y t h i n g of t h e m . T h e writer h a d seen t h e t u b e s designed b y M r . P a t r i c k , b u t wished a t u b e differing f r o m t h e m in some respects. As there is n o t h i n g complicated a b o u t these t u b e s , specifications were d r a w n u p a n d t h e t u b e s ordered from t h e glass-blower. T h e specifications were d e t e r m i n e d b y sealing t h e e n d of a glass t u b e of five-eighths of a n inch inside d i a m e t e r a n d using the a m o u n t s of material required i n exactly t h e s a m e w a y as in a n a c t u a l determination. After t h e mixture h a d settled for t w e n t y m i n u t e s , m a r k s were m a d e o n t h e t u b e in t w o places. T h e t u b e was first m a r k e d a t t h e lowest point o n t h e column of ether a t which t h e e t h e r could

be safely d r a w n o f f . T h e second m a r k was m a d e a b o v e t h e t o p of t h e e t h e r column a t a height t h a t would allow space for proper mixing. T h e t u b e was t h e n e m p t i e d a n d these t w o points were measured i n cubic centimeters. T h e y were f o u n d t o be 19.5 1 Presented at the 16th Annual Association of Food, Dairy and Drug 05cials. Seattle, July 9-12, 1912.

Vol. 6 , No. 4

a n d 85 cubic centimeters, respectively. T h e specifications were as follows: I . Inside d i a m e t e r of t u b i n g t o be five-eighths of a n inch. 2. D r a i n a g e t u b e t o be so placed t h a t t h e b o t t o m of t h e orifice is a t t h e 19.5 cc. point. 3 . C a p a c i t y of t h e t u b e t o be 8 5 cc. 4. M o u t h of t u b e t o be constricted t o fit t h e t a p e r of a cork stopper. A rough drawing was sent with t h e specifications. Fig. I shows a n e m p t y t u b e a n d Fig. 2 shows a t u b e w i t h a f a t d e t e r m i n a t i o n in i t . T h e height of t h e emulsion in t h e t u b e c a n easily be seen. W i t h some milks t h e emulsion m a y s t a n d a very little higher, b u t as y e t there h a s been n o difficulty with t h e t u b e s m a d e as specified. T h e t u b e s being a w k w a r d t o h a n d l e a n d t h e drainage cock r a t h e r fragile, t h e problem of a safe a n d convenient mode of handling presented itself. A t first t h e t u b e s were set in perforated blocks b u t when h a n d l e d in t h i s w a y t h e mixing h a s t o be done singly a n d t h i s is a r a t h e r slow m e t h o d . Finally a tilting r a c k was designed of t h e f o r m s h o w n in Figs 3, 4 a n d 5 , a n d this h a s been found well a d a p t e d t o t h e purpose. Boiled cork stoppers are used in t h e t u b e s a n d if well fitted will hold t h e small pressure developed witho u t trouble. T h e mixing of t h e milk with t h e a m m o n i a a n d with t h e alcohol is done quickly while holding t h e t u b e in t h e h a n d a n d w i t h o u t using t h e stoppers. T h e t u b e s are t h e n placed in t h e r a c k in a n upright position a n d t h e ethyl ether a d d e d a n d t h e cork stoppers placed firmly in t h e t u b e s . T h e tilting f r a m e with t u b e s is t h e n t u r n e d back as shown in Fig. 3 a n d again t u r n e d t o a n upright position, a n d this c o n t i n u e d a s long as necessary. T h e p e t r o l e u m ether is t h e n a d d e d a n d t h e process repeated. T h e rack is t h e n placed in t h e position shown i n Fig. 4,t h e wing-nut t i g h t e n e d t o keep i t a t t h i s angle a n d t h e contents of t h e t u b e s allowed t o settle. T h i s position p r e v e n t s

t h e emulsion f r o m r u n n i n g i n t o t h e outlet t u b e , which i t is liable t o do if t h e mixture is allowed t o settle with t h e t u b e in a n upright position. In t h i s way six d e t e r m i n a t i o n s can be extracted in t h e t i m e t h a t would be required b y one if held i n t h e hand' as the tubes are not in a w a r m h a n d , t h e r e is less pressure developed. After

Apr, 1914

T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY

settling for a proper t i m e t h e rack is t u r n e d t o an upr i g h t position, t h e flasks placed u n d e r the o u t l e t cocks as in Fig. 5 and t h e mixed ethers and fat d r a i n e d off. If closer drainage is desired t h e t u b e s m a y b e held in t h e h a n d while t h e last portion is drained off. Funnels and filter p a p e r s m a y b e placed i n t h e flasks if desired. STATEFOODCOMMISSION 1623 MANHATTAN BUILDING, CHICAGO

MODIFIED APPARATUS FOR THE PUTRESCIBILITY TEST B y A. M. BUS WELL^

The putrescibility test as described b y Jackson and H o r t o n 2 is m a d e i n a 2 5 0 cc. b o t t l e provided with a one-hoie rubber stopper carrying a medicine dropper w i t h a 5 cc. r u b b e r b u l b : 3 7 . 5 O C. is t h e t e m p e r a t u r e of incubation. T h e b u l b is collapsed a t t h e beginning of t h e t e s t b u t soon becomes partially filled, d u e t o t h e expansion of t h e liquid a n d t h e evolution of s o m e of t h e gases originally i n solution. E x p a n sion is t h u s allowed for without permitting t h e absorption of air. It has been found, however, t h a t the r u b b e r bulbs deteriorate v e r y rapidly. T h i s n o t only m a k e s the cost of up-keep of the a p p a r a t u s high b u t

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occasionally a test is lost, due to the failure of a bulb during incubation. These facts led t h e writer t o design for the putrescibility bottle the modified f o r m of stopper shown in t h e figure. T h e modification consists in replacing the medicine dropper by a J s h a p e d capillary tube of 0 .j m m . bore. T h e long e n d of t h e t u b e extends t o t h e b o t t o m of a small test t u b e which catches the 250 cc. overflow. T h e diffusion of gases t h r o u g h capillary t u b ing is so slight t h a t the prevention of air absorption is effected. Aside f r o m being more durable t h e modified stopper c a n be applied m u c h more easily and rapidly than the old f o r m a n d t h e convenience is quite an i t e m when j o t o I O O bottles h a v e t o be m a d e u p at one t i m e . T h e modified stopper h a s been used i n a series of comparative tests m a d e b y s t u d e n t s i n t h i s laboratory a n d t h e results obtained so far a r e entirely satisfactory. LABORATORY OF SANITARY CHEMISTRY COLUMBIA UNIVERSITY, NEW YORK

ADDRESSES MODERN CHEMICAL INDUSTRY3 By FRITZHABER

It is a special honor to me to speak here in appreciation of a man who recognized and represented the importance of physical thinking in applied chemistry at a time when almost without exception technical chemists declined to take this view. Thirty years ago, when Hurter’s activity was a t its height, the center point of chemical industry was the Leblanc soda process. Here in England a number of technical methods for the manufacture of sulfuric acid and Glauber’s salt, bleaching powder, soda, potash and the alkalies had been developed up t o a remarkable standard. It is impossible to admire too much the richness of inventive genius and the clearness of judgment which the technical chemists of this period developed in your country. The world has learned of them how to convert chemical laboratory reactions into industrial technical processes and how to build up a system of analytical controls which enables the manager to follow the chemical change in a complicated system of reactions on a large scale. The picture that technical chemistry exhibits to-day is quite different from that of thirty years ago. There is more brilliancy around the accomplishment of the organic than of the inorganic industries. The replacement of natural dyes by the products of coal tar, the extension of our medical resources by the manufacture of synthetic medicines, has gone far to extend the appreciation of chemical work and to produce the general conviction that chemistry is an inexhaustible field of economic possibilities. Indeed, one natural product after another falls into the domain of chemical synthesis, and chemistry is becoming the important factor in the economy of the tropical products which are used for industrial purposes. As soon as Instructor in Sanitary Chemistry, Columbia University. THIS JOURNAL, 1 (1909), 328. 8 The Hurter Memorial Lecture, delivered before the Liverpool Section of the Society of Chemical Industry, November 26, 1913 and printed in the Jour. Sac. Chem. Ind.. SS (1914). 49. 1

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the price of such a product exceeds a certain limit organic chemistry enters the field and synthesizes it in Western Europe. Thus indigo has succumbed to the onslaught of organic chemistry. Tanning materials a t present are in a struggle with the condensation products of formaldehyde and phenolsulfonic acids. Camphor could maintain its position only by large price reduction, and the ptospect of synthetic rubber holds down the would-be inflated prices of the natural product. The basis of this marked development in organic chemical industries is the combined working of science and technology. The fact and the success of this intermingling is so obvious that we need not dwell on the point. I n the territory of inorganic technical Chemistry things are somewhat different. Here also a great change has taken place. The historical sulfuric acid and soda processes have lost much ground to the ammonia-soda and electrolytic processes, and to the contact process. New branches of industries have taken root and grown up. In this field, however, the connection between scientific and technical progress is neither so obvious nor so well recognized as in the realm of industrial organic chemistry. The reason is that the advance in inorganic science, during the last decade or two, has resulted less in the discovery of new facts which had direct technical applications, than in the unravelling and working out of new theoretical views. In fact, the introduction of physical laws and physical methods into the working sphere of inorganic chemistry has led to the greatest scientific progress. The invasion of physics into chemistry has produced the splendid development of physical chemistry, the basis of which is the second law of thermodynamics, the phase rule, and the theory of electrolytic dissociation. The introduction of the electroscope into chemical analysis has opened up the new chemical world of radioactivity. Now, in my opinion, inorganic chemical industries can gain almost as much by regarding their problems from a physical point of view as organic industries do by the application of structural considerations.