AGRICULTURAL CHEMISTRY. 209 



ncid ;ui(l titratiup with fifliftli-iiurni.il sodium hydrate, using {-(tiigo red as an 

 indicator. 



The determination of total nitrogen according to Mitscherlich, E. Mekres 

 {Ztsclir. AiKjctv. Chvm., 22 (1909), A'o. i//, />/>. (hil. (iJ2 ; ah.s. in Vhcm. Zcntbl., 

 290!), I, ^'o. J8, pp. 1503, loO.'f). — A brief description of the method noted above, 

 its advantages, and the precautions to be observed to insure accuracy. 



The use of nitron for the determination of nitric acid in solutions con- 

 taining much organic matter, II. Franzen and E. LOhmann {Jour. Prakt. 

 Vhvm., n. 6Tr., 79 {1909), No. 7-8, pp. 3S0-33S; ahs. in Jour. Soc. Chvm. Inilita., 

 i:S {1909). A'o. 10, p. 5.'/6"). — Tests are reported which show that Busch's nitron 

 method gives good results in tlie presen.ce of relatively large amounts of organic 

 matter, as for example, in culture solutions, provided 2 to 2.5 cc. of concentrated 

 sulplniric acid be added for each 200 cc. of sohition. 



The determination of ammonia without a condenser, It. O. E. Davis {Jour. 

 Amrr. Chem. t<oc., 31 {1909), No. 5, pp. 5,')6-558, fig. /).— Tlie essential feature 

 of the apparatus described is an absorption device consisting of a Folin tube 

 supi)lemented by a tube filled with glass beads moistened with acid, the am- 

 monia being swei)t into the absorption device from the digestion flask by means 

 of a rapid current of air. 



The determination of phosphoric acid in fertilizers by Pemberton's modi- 

 fied method and by von Lorenz's method, 1). J. IIissink {Chvm. WcckhL, 

 6 {1909), No. 12, pp. 181-191; abs. in Chvm. Zentbl., 1909, I, No. 15, p. 1268).— 

 The author's moditicatiou of Pemberton's method has been previously noted 

 (E. S. R., 17, p. 6). The results obtained by this modified method agreed very 

 well with those of the von I.,oreuz n)>?thod. In lOS determinations made with 

 both methods the average variation was only 0.04 per cent. The von Lorenz 

 method is somewhat quiclcer than the Pemberton method, but the former uses 

 the more material. 



The use of the method is extended to include the determination of phosi)horic 

 acid in acid-soluble phosphates, as follows: Boil 5 gm. of substance for one-half 

 hour in 150 cc. of water. 40 cc. of nitric acid (1.2 sp. gr.), and. 10 cc. of 25 

 per cent hydrochloric acid, cool, dilute with water to 500 cc, filter, and proceed 

 as usual. 



A discussion of methods for determining the availability of phosphoric 

 acid in Thomas phosphate powder (basic slag phosphate), w^ith a complete 

 transcript of Wagner's method, (i. I >. Leavens (1908. pp. 39. figs. 2). — This 

 is a summary of information regarding the composition of Thomas slag, the 

 availability of its phosphoric acid as shown by field experiments, and the 

 relative merits of different chemical methods of determining availability. The 

 Waguer method is reconmiended as giving the most satlsfactoi'y results. 



A rapid method for the determination of total potassium in soils, O. M. 

 Shedd {Jour. Indus, and Engin. Chcm., 1 {1909), No. 5, pp. 302-30',).— The 

 method projKised, which is stated to be applicable not only to potash in soils 

 but to silicates generally, "is a combination of the J. Lawrence Smith method 

 with the cobalti-nitrite method of W. A. Drushel, the potassium being brought 

 into solution by the former method and determined by the latter, without 

 previous separation of the calcium." 



The determination of carbon by means of the bomb calorimeter, J. A. 

 Fries {Jour. Amcr. Chvm. Soc, 31 {1909), No. 2, pp. 272-278, fig. 1). — From 

 comparative determinations which the author reports tlie conclusion is reached 

 that carbon dioxid can be very accurately determined with the Atwater- 

 Berthelot bomb. 



