318 EXPEBIMENT STATION EECOED. 



Methods for the examination of bituminous road materials, P. HrsBAKD 

 and C. S. Reeve (U. S. Dcpt. Agr. Bui. SlJf {1915), pp. 48, figs. 20).— This is a 

 revision of Office of Public Roads Bulletin 38 (E. S. R., 25, p. SIO). "Since 

 the publication of Bulletin 38 considerable progress has been made in the 

 standardization of methods of examining bituminous road materials. . . . 

 Special attention is called to modifications in the penetration test, determina- 

 tion of fixed carbon, and determination of paraffin scale ; and to the substi- 

 tution of new methods for tlie old distillation tests and for determination of 

 voids in the mineral aggregate. In addition descriptions of the following 

 methods are given: (1) Determination of flash and burning points, open-cup 

 method, (2) dimethyl sulphate test, and (3) methods of examining bituminous 

 emulsions." 



Acid ratio; a new method for determining^ the proteolytic strength of 

 germinated g'rain in technical analysis, C. A. Nowak (Jour. Indus, and Engin. 

 Chem., 7 (1915), No. 10, pp. S5S, 859). — A new method, based on the S0rensen 

 formaldehyde titration procedure (E. S. R., 19, p. 808), is described in detail. 



The final results are not expre.ssed in absolute amounts of nitrogen present 

 but simply in comparative titrations of the malt extracts. " For brewing pur- 

 poses a malt having the greatest amount of amino groups is to be preferred, 

 but only provided the original acidity has been fairly high and the relation or 

 ratio between the formol acidity and the natural acidity, obtained by dividing 

 the number of cubic centimeters representing the amino acids by the number 

 of cubic centimeters representing the natural acidity, is as 1 : 1 or greater," 



This ratio, which the author designates the " acid ratio of malt," is an en- 

 tirely new factor in malt valuation. An advantage in simplicity and rapidity 

 over earlier methods is claimed. A further advantage is that one single deter- 

 mination suffices for the estimation both of the preformed amino acids present 

 in the malt and also the proteolytic strength. 



Alcoholic fermentation, A. Harden (London and New York: Longmans, 

 Orcen, and Co., 19U, 2. ed., pp. VII + ISG, figs. S). — A second edition of the 

 monograph previously noted (E. S. R., 29, p. 714). No change has been made 

 in the scope of the work, but many additions to the text and a considerable 

 increase In the bibliography have become necessary on account of the rapid 

 progress In the subject. 



The recovery of ammonia as a by-product of the sug'ar industry. E. 

 DoNATH (Zcnthl. Kunstdiingcr Indus., 20 (1915), No. 15, pp. 1S7-189). — Earlier 

 work on the ammonia content of the pressed juice of sugar beets is reviewed. 

 The author found the ammonia content of pressed juices to be greater than that 

 reported by previous investigators, due probably to dilTercnces in the procedure 

 of the determinations. Proposed methods and possibilities for such a recovery 

 due to the lack of nitrogenous fertilizing materials are discussed. 



Zacaton as a paper-making' material, C. J. Brand and J. L. Merrill (U. S. 

 Dept. Agr. Bui. S09 (1915), pp. 27, figs.- IS). — Experiments are reported which 

 indicate that zacaton grass (Epicampcs macroura) may prove to be a valuable 

 paper stock in the future. The grass can be chemically reduced to paper stock 

 by the soda process under less drastic and less expensive conditions than those 

 employed for the reduction of poplar wood. Processes, methods, and machinery 

 employed by the manufacturer of pulp from poplar wood were found entirely 

 suitable for the treatment of this m-itorial. The yield of air dry fiber from the 

 »ir-dry grass averaged 43 per cent. Paper manufactured from this stock showed 

 physical tests equal to those of first-grade, machine-finish printing i)ai)er. 



A botanical description and cultural notes on zacaton are also given. 



