1920] ■ METEOROLOGY. 15 



Determination of the saponification number of dark-colored resins, H/ 



Salvaterra {Chem. ZUj., 43 (1919), No. 134, PP- "^65, 766, figs. 3). —To avoid the 

 difficulty of observing tlie end-point in tlie ordinary titration witli phenol- 

 phtiialein or otiier indicators in tlie case of dark colored resins, the author sug- 

 gests two alternatives. In one, three samples of the resin are saponified in the 

 usual way, using fr(mi 2 to 4 gm. of the substance in each saponification. One 

 of these saponified samples is then titrated roughly with n/2 H2SO4. using as 

 an indicator 2 cc. of a 2 per cent alkali blue solution. The other samples, after 

 cooling, are treated with about 0.5 cc. less H2SO4 than the amount used in the 

 trial titration, made up to 200 cc. with alcohol, and filtered. An aliquot of the 

 filtrate (100 cc.) is then titrated, using either alkali blue or phenolphthalein as 

 indicator. 



In the other method, saponification is completed as usual, after wliich a solu- 

 tion of barium chlorid is added and the heating continued for some time 

 longer. This precipitates the barium soaps of the fatty acids and reacts with 

 the excess of potassium hydroxid. liberating barium hydroxid. 



"The fumaric acid fermentation of sugar, C. Wehmer {Ber. Deut. Chem. 

 GeselL, 51 [1918), No. U, pp. 1663-1668, flffs. 6).— The author states that the 

 fermentation of cane sugar by a variety of Aspergillus which he has named 

 A. fumaricus results in the formation of a considerable amount of fumaric 

 acid, together with a small amount of citric acid. The acid under ordinary 

 conditions is formed in the free state as an oxidation product of the sugar. In 

 the presence of calcium carbonate a crystalline mass of calcium fumarate is 

 formed, which, on isolation and purification, crystallizes from a water solution 

 in rosette-shaped crystals. 



INIicrophotographs are given of calcium and lead fumarate and of the free 

 fumaric acid. 



Fruit cook book, R. Mertens (Obsteinkochbilchlein fur den BiirgerUchen u. 

 Feincren Havshalt. Wiesbaden: Rtid. Bechtold d Co., 1918, 17, ed., rev., pp. 

 YII-\-176, figs. 70). — In tlie revision by E. .Tunge of this manual of directions 

 for preserving fruit, special advice is given in regard to choice of methods and 

 the selection of fruit during times of sugar shortage. The use of partially ripe 

 fruit is discouraged on account of its lower content of sugar. Similarly the 

 use of sugar-rich berries for wine making is discouraged on account of the loss 

 of sugar during fermentation. 



Drying problems of to-day, R. Schmidt (Ztschr. Angew. Chem., 32 (1919), 

 No. 30, Aufsatzt., pp. 108-113; abs. in Chem. Ahs., 13 (1919), No. 23, p. 3253).— 

 This is a general discussion of the practical problems involved in the successful 

 dehydration of foods and feeding stuffs, with particular emphasis on the selec- 

 tion of the proper method for dilferent materials, depending upon their structure 

 and the ease with which they give up moisture. 



The casein industry, .1. Pedersen (Neiu Zeal. Jour. Agr., 19 (1919), No. 6, 

 pp. 347-354). — With a view to obtaining a better quality of commercial casein 

 in New Zealand, the author enumerates various causes contributing to poor- 

 quality products and describes in detail several processes of manufacture, with 

 their advantages and disadvantages. 



METEOROLOGY. 



Predicting minimum temperatures from hygrometric data, .T. W. Smith 

 et al. (V. S. Mo. Weather Rev. Sup. 16 (1920), pp. 76, pi. 1. flgs. 52).— In addi- 

 tion to the leading paper by .T. W. Smith, with an introduction by C. F. Marvin, 

 an abstract of which has been previously noted (E. S. R., 42, p. 619), this num- 

 ber contains shorter articles on Cape Cod Cranberry Frosts, by H. J. Franklin ; 



