812 EXPERIMENT STATION RECORD. [Vol.40 



nium sulphate solution, or mercuric chlorid were added. Upland moor soils 

 were examined for ammonia, nitrites, and nitrates, then air dried at ordinary 

 temperatures and reexamined. With the exception of one sample which con- 

 tained traces of nitrate, these soils were found to be entirely free from both 

 nitrites and nitrates. Nitrification in peat soils is believed to be exclusively 

 a biological process. 



The reactions of the soils supporting the growth of certain native orchids, 

 E. T. Whebry (Jour. Wash. Acad. Sci., 8 (1918), No. 18, pp. 589-598; abs. in 

 Chem. Abs., IS (1919), No. 1, pp. 50, 51). — About 200 samples of soil supporting 

 the growth of all of the commoner species of orchids native to the east-central 

 States were studied with reference to acidity by a modification of the hydrogen- 

 ion concentration method, using indicators of different degrees of acidity. 



It was found that while there was considerable difference in the acidity 

 of soils supporting different species of orchids, " in every case the acidity of 

 the soils supporting each of these species varies within comparatively narrow 

 limits." The fungus living symbiotically on the roots of each species appears 

 to be less tolerant of changes in acidity than in moisture, for a given species 

 of orchid may be found in habitats varying widely in wetn 



The observations reported indicate that the growth of the tall Cypripediums 

 would be favored by the addition of a little powdered limestone to the soil. 

 "On the other hand most species require the soil to be made distinctly or even 

 strongly acid." 



Solubility of lime, magnesia, and potash in such minerals as epidote, 

 chrysolite, and muscovite. especially in regard to soil relationships, H. F. 

 Gardinkr (Jour. Agr. Research [I '. flf.], 16 (1919), No. 10, pp. 853 Ul).— In this 

 article, a contribution from the Bureau of Soils of the IT. S. Department of 

 Agriculture, experiments are reported in which epidote, chrysolite, and mus- 

 covite, groiyid to pass a sieve of 100 meshes to the inch, were kept in contact 

 for two months with a water extract of an acid soil at a temperature of 25° C. 

 (77° F.) The amount of soil extract in each case was 25 CC., and the amounts 

 of ground minerals varied from 0.1 to 1 gm. of epidote and chrysolite and from 

 0.1 to 0.4 gm. of muscovite. 



It was found that more potash was removed from muscovite than lime from 

 epidote or magnesia from chrysolite, and that on the whole more lime was 

 extracted from epidote than magnesia from chrysolite » >n the average 0/27 

 per cent of lime was dissolved from epidote and 0.17 per cent of magnesia 

 from chrysolite. 



"The removal of such proportionally large amounts of lime and potash from 

 .silicates by an acid soil extract would seem to Indicate that In time a soil's 

 fertility Index, with respect to lime and potash, would under proper conditions 

 of acidity he quite appreciably lowered." 



The nitrogen content of volcanic ash in the Katmai eruption of 1912. J. W. 

 Shipley {Ohio Jour. Sci., 19 (1919), No. 4, pp. 21S-22S, figs. S).— A study of the 

 nitrogen content of volcanic ash from various places in the area devastated by 

 tbe eruption of Katmai in 1912 shows that the amount of nitrogen present Is 

 so small as to preclude the possibility of vegetation securing its nitrogen supply 

 from decomposition of the volcanic detritus. The total nitrogen found was k 

 than one part per hundred thousand. It was observed that although the soil 

 is almost devoid of nitrogenous compounds, lupines thrive and produce seed 

 in abundance. 



The water soluble salt content, the ferrous iron content, and the acidity 

 of Katmai volcanic ash, J. W. SHIPLEY {Ohio -lour. Sri.. 19 (1919), No, \, /•/». 

 224-229, figs. 2). — Examinations of the ash. which had been found to be toxic 



