614 EXPEKIMENT STATION RECORD. t Vol. 30 



Experiments in which the excess of molybdenum was removed as sulphid 

 showed this step to be of no advantage either in the determination of calcium 

 or in the complete ash analysis. 



A comparison of the proposed procedure with the official basic acetate method 

 (E. S. R., 20, p. 512) shows that the new method yields more accurate and 

 concordant results and does not require exact neutrality of the solution. The 

 filtrate from the phosphorus precipitation is small enough so that no evapora- 

 tion is necessary, the time required for the determination is greatly shortened, 

 and phosphorus and calcium may be determined in the same aliquot. 



The basic acetate method is reviewed and certain difficulties encountered by 

 the author in securing concordant results in the later determination of man- 

 ganese, calcium, magnesium, and the allvalis are pointed out. 



Some analytical data of the calcium in the ash of pig carcasses are sub- 

 mitted. 



A new limestone tester, G. G. Hopkins {Illinois Sta. Bui. 194 (1917), pp. 

 487-495, fig. 1). — A limestone tester much simpler than the one previously 

 noted (E. S. R., 34, p. 806) and its manipulation are described in detail. The 

 test consists essentially of converting a weighed sample of the limestone into 

 calcium chlorid with dilute hydrochloric acid saturated with carbon dioxld 

 and determining the loss in the i-eaction. The percentage of calcium carbonate 

 in the original sample is then easily determined by a simple calculation. 



Tables showing milligrams of carbon dioxid per cubic centimeter of satu- 

 rated gas and weight of dry air in milligrams per cubic centimeter of satu- 

 rated atmosphere, together with some brief notes on limestone samples and 

 the use of limestone for soil improvement, are submitted. 



The determination of humus by means of a simplified procedure of ele- 

 mentary analysis, A. Lakobsen {Zhur, Opytn, Agron. {Jour. Ayr. Expt.), 17 

 {1916), No. 2, pp. 93-98, fig. 1). — A combustion method for the determination of 

 humus in soils, in which platinized asbestos is used as the catalyst, and Its 

 manipulation are described in detail. Oxidation with from 1 to 2 gm. of 

 material can be effected in from 25 to 30 minutes, and the results obtained 

 are identical with those obtained by the procedure of Gustavson. 



Advantages claimed for the modified procedure are rapidity of combustion, 

 economy of materials, and simplicity in manipulation. 



The estimation of carbohydrates. — V, The supposed precipitation of reduc- 

 ing sugars by basic lead acetate, W. A. Davis {Jour. Agr. Set. [Englatidl, 8 

 {1916), No. 1, pp. 7-i5).— Continuing previous studies (E. S. R., 33, p. 712), the 

 author submits results which show that, at least in dilute solutions, levulose 

 is never precipitated by basic lead acetate, even in the presence of chlorids, 

 sulphates, or carbonates. There is no loss of levulose unless the excess of 

 basic lead acetate is allowed to act for some length of time on the sugar 

 before the lead is precipitated. Only a slight excess should be used in the 

 defecation of the sugar solution and this excess removed as soon as possible 

 after the precipitation is complete. 



It is indicated that basic lead acetate is more effective as a clarifying agent 

 than is normal acetate, and if it is " added carefully in small quantities at a 

 time until the precipitation of the impurities is just complete and the actual 

 excess of the basic lead acetate solution is not allowed to exceed about 5 cc. 

 in 300 to 500 cc. of the solution, there is no loss whatever of levulose or other 

 reducing sugars." 



New contributions to the analysis of milk, E. Ackermann {Scliweiz. Apoth. 

 Ztg., 54 {1916), No. 42, pp. 57S-578).— Tabular data of the total solids, lactose, 

 lactose-free solids, and refractive index of the serum of normal cows' milk, 



