Geology and Mineralogy. 75 



By examination of the above table it is to be seen, that the 

 leaves of the flowering hemp contain more of the essential min- 

 eral ingredients of the soil than all the other parts of the plant; 

 constituting as they do. about 30 per cent of the whole plant in 

 the air-dried state, and yielding \0-2ir, per cent of their weight of 

 ash, the carbonic acid being excluded ; while the stems and roots, 

 which together form the remaining 10 per cent of the weight of 

 the plant, give an average of less than 3-5 per cent of ash. 



Nor is this great excess in the proportion of ash in the leaves due 

 entirely to the influence of the greater evaporation which takes 

 place on their surfaces, causing a deposit or incrustation of lime 



see that while the amount of silica in the leaves is nearly fourteen 

 times greater than that in the stems, and more than seven times 

 greater than in the roots; the lime more than five times as great 

 as that in the stems, and seven times more than in the toots ; the 

 magnesia three times more than that in the stems, and twice as 

 much as that in the roots; the phosphoric acid and phosphates 

 and the alkalies are in nearly double proportion in the leaves also, 

 and the sulphuric acid five" times greater in them than in the 

 stems, and about four times greater than in the roots. So that 

 while the leaves, when in their fully matured state or when they 

 naruraily fall, may possibly contain scarcely any but the less 

 soluble salts which may be left in their tissues on the evaporation 

 of the carbonated water which held them in solution in the sap, 

 they contain, wdien in the growing, active condition, like all other 

 green herbage, a very large proportion of salts of potash, and of 

 all tin mineral elements of plant nourishment, and hence may 

 greatly enrich the soil on which they decay. It is obviously to 

 the interest of the hemp farmer, therefore, so to manage as to 

 spread them as regularly as possible over his hemp ground. 



•;. The American Bison, Living and Extinct : >.v J. A. Ar.r.Ex. 

 Published, by permission of N. S. Shaler, Director of the 

 Keittuckv Geological Survev. as vol. iv, No. 10, of the Memoirs 

 of the Museum "of Comparative Zoology at Harvard College. 

 Cambridge, Mass. 246 pp. 4to, with 12 plates and a colored map. 

 (Weld Uigelmv & Co.i I'liis work I. uttit'ul in tyi graphy, is 

 well as I;, its illustrations, is a carefully prepared monograph of 

 the American bisons, containing, as its first part, descriptions of 

 the species, and, as 'its second, a thorough discussion of their 

 geographical distribution. Two extinct species are recognized. 

 Bison latifroas Leidv, and II. antiq'ins Leidy t= /»'. cra,sa-orms 

 Richardson). To the description of Bison Americana* the author 

 Has added much information on the habits of the species from his 

 own observations. The fine colored map is introduced to illustrate 

 its former and present distribution. 



4. Second Geological Survey of Pennsylvania. Hams- 



