FUNCTION.] SULPHUROUS AND MURIATIC ACID GASES. 311 



WHEAT. 



CLOVER. 



The Wheat fixed a great deal of carbon and water, but no 

 hydrogen ; whilst the Clover fixed carbon, nitrogen, hydrogen 

 and water. (Dumas Traitede Chimie appliquee aux Arts, torn, 

 viii. p. 441.) 



Drs. Turner and Christison found that so small a quantity 

 as 10000 of sulphurous acid gas, a proportion so minute as to 

 be imperceptible to the smell, was sufficient to destroy the 

 life of leaves in forty-eight hours. The same observers state, 

 in their paper in Brewster's Journal for January, 1828, the 

 effects of other gases upon plants. Hydrochloric, or muriatic 

 acid gas was found to produce effects not inferior, nay, even 

 superior, to those of the sulphurous acid. It was found 

 that so small a quantity as a fifth of an inch, although diluted 

 with 10,000 parts of air, destroyed the whole vegetation of a 

 plant of considerable size in less than two days. " Nay, we 

 afterwards found that a tenth part of a cubic inch, in 20,000 

 volumes of air, had nearly the same effects. In twenty-four 

 hours the leaves of a laburnum were all curled in on the 



