1919] FOILS — FERTILIZERS. 123 



soil the results were In general similar to those for the soil alone, exr-ept for 

 the larger amounts of carbon dioxid given off. Calcium carbonate in this 

 soil caused no marked increase or decrease in the growth of molds. Steriliza- 

 tion in the autoclave increased the nitrate, ammonia, and soluble nonprotein 

 nitrogen, while sterilization in the Arnold sterilizer, increased the ammonia 

 and soluble nonprotein nitrogen to a less extent and decreased the amount of 

 nitrate. Molds in all cases caused a diminution in the amount of nitrates, 

 while ammonia was not much changed in amount. In nearly every case there 

 was a decrease in the amounts of soluble nonprotein nitrogen. 



The inversion of cane sugar by soils and allied substances and the nature 

 of soil acidity, F. E. Rice and S. OstTGI (Soil Sci., 5 (1918), No. 5, pp. 888- 

 858). — The authors describe a method for measuring acidity in soils through 

 the inversion of sucrose in 50 cc. of a solution of cane sugar to which has been 

 added from 5 to 10 gm. of the soil to be examined. They also present the re- 

 sults of considerable experimental work done at Cornell University upon the 

 inversion of cane sugar by several different soils, the character of the soil 

 extracts, the acidity due to the solid phase of the soil, inversion by other solid 

 substances, the effect of hydrous oxids on cane sugar, and upon inversion and 

 selective adsorption. Their conclusions may be summarized as follows : 



Soils of many kinds and other insoluble materials can be made to invert 

 sucrose. With soils this power is deemed to be a property of the mineral por- 

 tion as well as of the organic matter. Furthermore, it is believed that this effect 

 is due to acid and that this acid may occur in four different forms as follows: 

 (1) A slight quantity in a few soils is soluble in the sugar solution. The prin- 

 cipal portion, however, is bound to the soil particles in the nature of (2) acids 

 which would otherwise be easily soluble, but are here strongly adsorbed on the 

 soil particle surfaces, or (3) an insoluble acid such as silicic acid. Also (4) a 

 neutral salt present in the soil solution in even small quantities may be broken 

 down while in contact with the soil mass, the basic part being more strongly 

 adsorbed than the acid, and the latter left free to exert its characteristic 

 influence in inverting cane sugar. 



That the inverting activity of soils is chiefly a property of the insoluble part 

 is said to have been indicated in several ways. Many soils showed inverting 

 action on sugar in a solution which remained neutral after contact with the 

 soil or in some instances became alkaline. Also, when soil was allowed to 

 adsorb some base, then digested with cane sugar solution, it showed inverting 

 action and also yielded up sufficient base to make the extract distinctly alkaline. 

 Very little, if any, inverting power was found in water extracts from soils. 

 Inversion did not continue in sugar extracts after the soils were removed. In- 

 version increased with increasing amounts of soil in contact with the sugar 

 solution, while there was no measurable change in the hydrogen-ion concentra- 

 tion in the extract. Greater inversion was produced by shaking soils with 

 sugar solutions than by allowing the mixtures to stand quiet. Long continued 

 and repeated extractions of soils with water and with cane sugar solution did 

 not greatly reduce their inverting power. 



Fuller's earth, cotton, charcoal, and other substances sometimes described as 

 similar to acid soils were found not to invert cane sugar. Otherwise soluble 

 acids so strongly adsorbed by solids as not to be removed by washing in any 

 measurable quantity inverted sugar in such condition. Silicate minerals were 

 given inverting power by treating suspensions with direct current, the base 

 splitting off and passing into solution and to the cathode and insoluble silicic 

 acid remaining with the mass. Soil acidity is said to be increased by a similar 

 treatment of soils. Contrary to previous conclusions, hydrous oxids of lead, 



