NOTES FROM T H E U. S. B U R E A U OF CHEMISTRY.*

T H E H Y D R O L Y S I S O F A U R A M I N E . 1

By W a l t e r C. H o l m e s and J. Fe r r i s Dar l ing .

[ABSTRACT.]

DATA defining the dependence of the rate of hydrolysis of auramine in aqueous solution upon temperature and acidity have been recorded.

A volumetric method, which is of particular value in deter- mining the quantity of auramines present in dye mixtures, may be based upon their hydrolysis.

Auramine G is appreciably more resistant to hydrolysis than is auramine.

T H E N O N - V O L A T I L E A C I D S O F T H E P E A C H . '

By E. K. Nelson.

[ABST~ACT.]

EXPERIMENTS conducted in the Bureau of Chemistry have shown that the non-volatile acids of the peach consist princi- pally of a mixture of /-malic acid and citric acid in almost equal proportions.

C H E M I S T R Y A N D C A N D Y M A N U F A C T U R E ?

By H. S. Pa ine and J. H a m i l t o n .

[ABSTRACr.]

FOg years the craft secrets of the confectionery industry have been guarded jealously and handed down from generation to generation. The chemist has played no part in the development of this industry. As a consequence, few of the procedures in

* Communicated by the Chief of the Bureau. 1 Published in J. Ant. Chem. Soc., 46 (October, I924) : 2343. * Published in J. Am. Chem. Soc., 46 (October, I924) :2337. • Published in Confectioners J., 5o (June, July, August, 3924) :9 I, 87, 87;

and in The Manufacturing Confectioner, 4 (May, July, and August, I9~4) : 26, I6. 22. Somewhat same subject-matter was published in Ind. Eng. Chem., x6 (May, I924) : 513, under title " Constructive Chemistry in Relation to Confec- tionery Manufacture."

833

832 U . S . BUREAU OF CHEMISTRY NOTES. [J. F. I.

candy manufacture have been interpreted from the standpoint of the chemical and physical theories governing them.

In their expert manipulations of syrups, crystallization of sugar, and the like, candy makers are really dealing with sugar chemistry, although they may not be aware of it. Obviously, therefore, a knowledge of the chemical laws upon which their operations are based will go a long way in clearing up the diffi- culties they now encounter.

With this end in view, the Bureau of Chemistry has conducted an investigation of the fondant type of candy which has shown that the application of chemistry may affect the various manufac- turing processes and the character of the finished product. Chemistry in the confectionery industry need no longer be con- fined to the analytical control of raw materials.

Further experiments along this line have shown that invertase may be successfully and economically used in making candy of the fondant type.

Stainless Chromium Steels.mThese alloys have attracted a great deal of attention of recent years, and "~¥. H. HATFIELD, Of the Brown- Firth Laboratories, of Sheffield, England, has presented a paper on some recent investigations concerning them. The presence of chro- mium in steel increases its resistance to nitric acid, but when present in large amount the solubility in hydrochloric and~ sulphuric acid is increased. There is evidence that the presence of chromium under strongly oxidizing influence permits of the immediate modification of the surface of the metal, in such a way as to produce complete passivity under certain conditions of temperature and concentration of the corroding media. As might be expected, the presence of colloids modifies the action of corrod~ing agents.

An appendix contains a list of media that the stainless steel resisted and those which it did not. The items in both cases are numerous. Malt vinegar, for example, had a low corrosive action while acetic acid vapor was corrosive. Vinegar, lemon juice and sour milk are not very active on the steel, but the isolated acids in the same strength as in the organic mixture do attack it. These results agree with those that were announced not long ago by other investigators. (Proceed- ings of the American Electrochemical Society, October, 1924. )

H . L .