MEMOIR OF LAMARCK. 23 



men a, indulging his fancy in forming conjectures 

 about their nature and origin. This circumstance, 

 he himself states, first inspired him with a desire to 

 study meteorology; and we can perceive in these 

 solitary meditations, one of the causes which tended 

 to give their fanciful complexion to many of his 

 subsequent speculations. 



After continuing his physical studies with much 

 ardour for several years, he at length appeared in 

 the character of an author. His " French Flora, or 

 a brief Description of all the Plants which grow 

 naturally in France," was published in 1778- The 

 immediate occasion of this work was a desire to 

 furnish his fellow-students with a system of arrange- 

 ment which should lead with greater ease and 

 certainty to the determination of plants than any 

 then in use. For this purpose he adopted a modi- 

 fication of the binary or dichotomous method, the 

 principle of which consists in arranging natural 

 objects by their positive and negative characters, 

 dividing and subdividing always by two, and allow- 

 ing a choice only between two opposite characters. 

 Although this plan is, of course, highly artificial, 

 and ill calculated to throw light on the affinities and 

 analogies of objects, yet it is much recommended 

 by its extreme simplicity, which adapts it to the 

 comprehension of those who have but little acquaint- 

 ance with the technical and descriptive language of 

 natural history. If judiciously applied, it affords an 

 easy index to particular genera and species, and 

 renders the subject at once accessible without any 



