100 REVIEWS. 



and no botanist of his age is more competent, or so well 

 placed and furnished for the investigation of this problem, to 

 which we invite him as to a task worthy of his powers. 



As to the rank of BalcmophorecB, if our author has demon- 

 strated anything, it is that they belong to the highest class of 

 plants, but that they are probably the most degraded members 

 of it. 



BOUSSINGAULT ON THE INFLUENCE OF NITRATES 

 ON THE PRODUCTION OF VEGETABLE MATTER. 



Several years ago Boussingault demonstrated, in the 

 clearest way, that jjlants are incapable of assimilating the 

 free nitrogen of the atmosphere. Two years ago, in a paper 

 communicated to the French Academy of Sciences, he showed 

 that nitrates eminently favor vegetation. He now shows,^ 

 by decisive experiments, — 



(1) That the amount even of ternary vegetable matter 

 produced by a plant depends absolutely upon the supply of 

 assimilable nitrogen (ammonia and nitrates). A jjlant, such 

 as a sunflower, with a rather large seed, may grow in a 

 soil of recently calcined brick, watered with pure water, so 

 far as even to complete itself with a blossom ; but it will only 

 have trebled or quadrupled the amount of vegetable matter 

 it had to begin with in the seed. In the experiments, the 

 seeds weighing 0.107 grams, in three months of vegetation 

 formed plants which when dried weighed only 0.392 grams, 

 — a little more than trebling their weight. The carbon they 

 had acquired from the decomposition of carbonic acid of the 

 air was only 0.114 grams; the nitrogen they had assimilated 

 from the air in three months was only 0.0025 grams. 



(2) Phosj)hate of lime, alkaline salts, and earthy matters 



^ Researches upon the Influence which assimilable Nitrogen in manures 

 exerts upon the production of Vegetable Matter ; and (2) Upon the Quanfitif 

 of Nitrates contained in the Soil and in Water of various kinds. J. B. J. D. 

 Iiou.ssi!ip;iult. Annates des Sciences Naturelles, 4 ser., vii., No. 1, 1857. 

 (Aiueiicuii JuuruiU of Science and Arts, 2 ser., xxv. 120.) 



