RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



Treatise on applied analytical chemistry, V. Vni IVECCHIA, trai P. H. 



Pope {Philadelphia: P. Blabiston'a 6 I •.. 1918, vol$. I. pp. XTJ+475, pi I. 



fig*. 52; 2, pp. ZIV+586, pis. u, figs, .v.)).— This treatise consists of two vol- 

 umes. The first .Ii'mIs with the analysis of potable waters, chemical produi 

 fertilizers, cement materials, metals and alloys, furls, tar and its derivatives, 

 and mineral oils and Catty substances and the Industrial products derived there- 

 from. The second treats "f flesh foods, milk products, flour and starches, 

 sugars Mini saccharin products, beer, wine, spirits and liqueurs, essential oils, 

 turpentine, varnishes, rubber, tanning materials, inks, leather, coloring matters, 



textile fibers, yarns, ami fabrics. 



A method for preparing a commercial grade of calcium arsenate. .1. K. II \v- 

 wood and 0. M. Smith (I . 8. Dept. Igr. Bui. 750 {1918), pp. 10).— The authors' 

 studies have led to the conclusion that the most desirable procedure for making 

 calcium arsenate from lime and arsenic acid is as follow-: 



"Use a good grade of lime, containing a high percent) Slake the 



lime to as smooth m paste :i- possible, for Dpon this depends the smoothness of 

 the t'mal product, as well as the readiness with whieh the lime and acid react. 

 I se from three to three and one half times as much water, by weight, as lime, 



and have it, preferably, warm. Let stand for a while, then thoroughly mix, 



after whieh add twice as much hot water as used for slaking, and mix again. 

 "The lime and arsenic should he in such proportion that the weight of actual 



OaO used will equal that of the A^<>. ased. This gives a product with a 



molecular ratio slightly over t. which is necessary if the soluble As«0i la t" he 

 kept down to desirable limits. Add the add at room temperature to the lime 

 as cpiickiy as possible, and stir well until the liquid becomes alkaline to phe- 



DOlphthaleln. Filter to as dry a State a- possible, do not wash, and if a dry 

 product is desired dr\ directly in any suitable manner, ("rush in a suitable dis- 

 integrator, or grind if necessary. 



"To produce 100 Iba of a commercial grade of calcium arsenate bj this 

 process win require 46 Iba <>f OaO (approximately 60 lb& of a high-grade 



lime) to he slaked with 1S gal. of water, the addition of 36 gal, more of water, 

 am! then 46 gal. of a solution containing 1 lb. of AjsiOi per gallon. Slight da* 

 parture from the figures given for water will probably have little effect." 



Chemistry of sweet-clover silage in comparison with alfalfa silape. 

 Swanson and B. L. Tague {.Jour. Agr. Retearch \l'. N.l. 1.', (1918), /■/>. 



118-182, figs. 5).— In continuation of Investigations made at the Kansas i 

 periment Station, previously noted (B S. R., ■"•7. p. 7"'.''. a comparative study 



is reported of the chemistry of silage made from alfalfa alone, from sweet clover 

 alone, and from sweet clover and corn meal. Quart milk bottles were used as 

 containers for the Silage. Several bottles of each kind of silnire were made and 

 opened at increasingly longer intervals of time, and the progressive Chemical 



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