Biographical Memoir of Charles Bo^met. SI 9 



x]^ the other parts of the vegetable. He shewed that there is no 

 circulation, properly so called, in plants. He made observations 

 respecting the internal structure of the vegetable. He proved 

 that pure water and atmospheric air are sufficient for nourishing 

 plants, — a result which might have immediately led to the great 

 discoveries of modern chemistry regarding the composition of 

 water and carbonic acid, had not a knowledge of many other 

 phenomena still been necessary to suggest the want of this solu- 

 tion, and to pave the way for these discoveries. 



These researches occupied Bonnet for twelve years ; and, 

 from the scrupulous accuracy, and delicate sagacity so conspi- 

 cuous in them, as well as the solidity of their results, they form 

 his best title to distinction. 



What secrets might not such a mind have unfolded, after so pro- 

 mising a commencement, had nature left him the physical powers 

 necessary for observation ? But his eyes, weakened by the use of 

 the microscope, refused him their assistance ; and his mind, too 

 active to endure a state of absolute repose, threw itself into the 

 field of speculative philosophy. From this period his works as- 

 sumed a new character, and he now only treated of those general 

 •questions that have, in all ages, engaged the meditative faculties 

 of the human mind, and which will probably occupy them as 

 long as the world continues to exist. 



In the writings of his maturer age, however, we recognise, by 

 the facts which are every where incorporated with them, and the 

 care with which he avoids losing himself in systems founded 

 upon the abuse of abstract terms, the philosopher who has en- 

 tered the region of metaphysics by the path of observation. 

 The choice of Malebranche and Leibnitz for his guides, and the 

 discriminating selection which he made of their views, always 

 recall to his thoughts his first pursuits. 



But what especially characterised them were those physical hy- 

 potheses which he always added after having exhausted the field 

 of observation, and by which he still seemed anxious to present 

 to the mind objects of external perception, when the senses re- 

 fused to present them to him. This necessity of clear and al- 

 most tangible ideas, which constitutes the true spirit of Cartesia- 

 nism, had been carefully inculcated in the old Acadeiny of Science, 

 and Bonnet had been impressed with it by his correspondence 

 with Reaumur, 



