SECT. I. CONDITIONS. i 



cess of germination, at a period when the study of 

 mechanical pneumatics was but yet in its infancy. 

 It was not yet foreseen that chemistry, lending its 

 aid to the developement of the causes of the phe- 

 nomena of vegetable life,, was to elucidate by means 

 of pneumatical discovery, the mysteries of germi- 

 nation. But this has proved to be the fact. The 

 discovery of the several gases, and of their various 

 chemical properties, has contributed more than all 

 other circumstances put together, to explain and 

 elucidate the phenomena of vegetation. The first By 



... . . * . Scheele, 



experiments on this obscure but interesting subject 



are those of Scheele ; who discovered soon after an(lolhers - 

 the introduction of pneumatic chemistry, that 

 Beans did not germinate in any kind of gas 1 in- 

 differently ; but that oxygene gas is necessary to 

 the process. Achard afterwards proved that no 

 seed will germinate in nitrogene gas, or carbonic 

 acid gas, or hydrogene gas, except when mixed 

 with a certain proportion of oxygene gas ; and 

 hence concluded that oxygene gas is necessary to 

 the germination of all seeds_> and the only con- 

 stituent part of the atmospheric air which is ab- 

 solutely necessary. 



The experiments of M. Achard were afterwards Who find 

 repeated and confirmed by a number of other 

 chemists, particularly Cruickshank and Saussure, 

 who found that seeds will not only not germinate 

 in nitrogene gas, but will die if put into it even 

 after germination has been begun, at least if the 



