1916] AGRICULTURAL CHEMISTRY — AGROTECHNY. 717 



36° B. added, the volume made up to 300 cc, and the liquid m\xed and filtered. 

 It is now polarized by introducing 100 cc. into a 100-110 cc. flask, adding 5 cc. 

 of acetic acid and sufficient water to reach the upper mark, treating with 2 gm. 

 of special dry decolorizing carbon, mixing, and filtering, the observation being 

 made in the 400 mm. tube. 



It is indicated that the method is simple, rapid, and certain. " It is . . . 

 applicable to all cane-sugar factory products, but not to special products such 

 as those of the beet-sugar factory containing glutamic and aspartic subetances, 

 the optical activity of which is not destroyed by the bismuth reagent." 



The determination of essences in liqueurs, X. Rocques (Ann. Falsi/., 9 

 (1916), No. 90-91, pp. 127-1S4) .—These pages report the findings of the com- 

 mittee appointed to investigate methods for the determination of volatile oils 

 in liqueurs, necessitated by the recent legislation in France which ruled that 

 not more than 0.5 gm. of oil be used in 1 liter of liqueur. 



The volumetric method of Ronnet and the gravimetric method of Muttelet, 

 both previously noted (E. S. R., 35, p. Ill), are recommended as being satis- 

 factory for the control of the purity of these products. The methods are 

 described in detail and comparative analytical data submitted. 



Manual for the essence industry, E. Waltkb (New York: John Wiley d /S'ons. 

 Inc., 1916, pp. in-\-.'j2T, figs. 37). — This volume describes the most modern 

 methods for preparing all kinds of-essences for liquors, brandies, liqueurs, and 

 all alcoholic drinks, fruit juices, fruit wines, and mineral waters, together with 

 many other valuable formulas. Other topics considered are the taste and the 

 transfer of flavor to foods and beverages ; the raw materials yielding the differ- 

 ent tastes ; confectionery, bakery, and culinary essences ; coloring matters for 

 foods and drinks; and cosmetic essences (perfumery, cosmetics, and soap per- 

 fumes). A chapter on laboratory practice, consisting of general manufacturing 

 and analytical methods, is included, and a complete subject index is appended. 



Canning in g'lass by the cold pack method, Bab Bell and Addie D. Root 

 (Univ. Missouri Col. Agr. Ext. Serv. Circ. 9 (1916), pp. 12, figs. 6). — This circu- 

 lar briefly discusses the subject under the following heads : Why fruits and 

 vegetables spoil ; types of canners which may be used ; and jars. tops, and 

 rubbers. Directions for canning various fruits and vegetables are outlined in 

 detail. 



Some possibilities for the utilization of low-grade and surplus fruit, .T. S. 

 Caldwell (Washington Sta. Popular Bui. 102 (1916), pp. 4)- — This briefly sum- 

 marizes the material previously noted (E. S. R., 35, p. 418). 



Single-variety ciders and perry, 1913—14, B. T. P. Barker and O. Grove 

 (Univ. Bristol, Ann. Rpt. Agr. and Hort. Research Sta., 1914, PP- 11-21). — These 

 pages record analytical data on a number of single-variety ciders and a peri-y 

 made from fruit collected during the season of 1913, together with remarks on 

 the general character of the products. The analytical data include specific 

 gravity, malic acid and tannin content, weight of fruit, yield of juice, and 

 variations in the specific gravity after fermentation and bottling. 



The treatment of cider sickness, O. Grove (Univ. Bristol, Ann. Rpt. Agr. and 

 Hort. Research Sta., 1914, pp. 22-24). — Experimental data have demonstrated 

 that cider sickness can be remedied or prevented by either of the following 

 methods: (1) Increasing the acidity, either by mixing a cider of low acidity 

 with one which is naturally high or by adding a sufficient amount of tartaric 

 acid, equivalent to about 0.5 per cent malic acid; or (2) the use of brewer's or 

 compressed yeast. Increasing the acidity has yielded the most desirable 

 results. 



The use of sulphur dioxid and aeration yielded negative results. 



