614 EXPEEIMENT STATION EECOED. 



Spirit of nitrous ether, H. H. Hanson and A. K. Burke (Maine 8ta. Bui. 201, 

 pp. lIfl-158, fig. 1). — The factors bringing about the deterioration and decom- 

 position of spirit of nitrous ether, commonly called sweet spirits of niter, were 

 studied. A sample of the product kept in strict accordance with the directions 

 given by the United States Pharmacopoeia maintained constant strength for 60 

 days and decreased only slightly the next 30 days. Under less favorable condi- 

 tions decomposition began at once and steadily continued. 



When determining the amount of ethyl nitrite in spirit of nitrous ether by 

 liberating the nitrogen dioxid and measuring the gas in the nitrometer, the vol-- 

 ume did not become constant in from 30 to 60 minutes' time as one would be led 

 to suppose by the directions given in the Pharmacopoeia, but was found to 

 increase slowly and at a varying rate, and was influenced by various factors. It 

 is not deemed practicable to attempt to obtain an absolutely constant volume 

 nor to apply a factor as a correction for the last traces of gas. A modified 

 method of analysis, for which better results are claimed than with either the 

 old or new Pharmacopoeia methods, is described. The modified method is con- 

 sidered more economical in time and reagents, and can be more easily manipu- 

 lated. 



Use of saponin for lioniogenizing samples of milk to be examined, A. Fkouin 

 {Ann. CJmn. Analyt., 16 (1911), No. 12, pp. ^5//, 455; abs. in Chem. Abs., 6 

 (1912), No. 6, p. 781). — It often happens that milk samples destined for exami- 

 nation after standing for several months can not be properly homogenized by 

 shaking, etc. If bile is added to such milk a uniform suspension can be ob- 

 tained, but the mixture putrifies very easily. When saponin is added to milk 

 previously neutralized to litmus with ammonium hydroxid in amounts of 0.005 

 gm. to 100 cc. of milk, and the mixture is heated from 40 to 56° for 10 min- 

 utes amid frequent shaking, a well homogenized mixture is obtained which will 

 not interfere with the analytical results. 



A nev/ method for determining fat and salt in butter, especially adapted 

 for use in creameries, R. H. Sii.\w (U. S. Dcpt. Agr., Bur. Aiuni. Indus. Circ. 

 202, pp. 8, fig. 1). — The procedure consists of melting the butter at 100° F.. 

 mixing it thoroughly with a spatula or spoon and weighing off 20 gm. in a 

 small beaker, transferring the melted butter to a special form of separating 

 funnel of known weight with the aid of water, centrifuging in a Babcock cen- 

 trifuge about 1 minute, drawing ofl: the water containing the salt and then dis- 

 solving the curd with dilute suljihuric acid (9 cc. of cold water and 11 cc. of 

 sulphuric acid). After centrifuging again for 1 minute the acid solution con- 

 taining the curd is drawn off and the separatory funnel containing the fat is 

 weighed. The separatory funnel and the special form of socket for holding it 

 in the centrifuge are illustrated. Results obtained in the test compared reason- 

 ably well with those given by the oflScial method. 



The washings from the above test are used for determining the salt content, 

 by estimating chlorin with a volumetric solution of nitrate of silver (14.525 

 gm. per liter), using a 10 per cent potassium chromate solution as the indi- 

 cator. If the moisture content of the sample is known the percentage of curd 

 can be found by difference. 



The index of refraction of the mixed acids of fatty oils, W. B. Smith 

 (Jour. Indus, and Engin. Chem., 4 (1912), No. 1, pp. 36-38; abs. in Jour. Soc. 

 Chem. Indus., 31 (1912), No. 3, p. 139; Science, n. ser., 35 (1912), No. 897, p. 

 881). — "The relation between the refraction of the oil and the refraction of 

 the acids depends upon the percentage of acid in the glycerids, being nearly 

 independent of the total refraction and of the iodin value." 



The ratios between the refraction of oils and their insoluble acids were 

 determined, For linseed, cod-liver, soy-bean, corn, rape-seed, cotton-seed, pea- 



