MEMOIR OF LAMARCK. 
23 
mena, 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 hut 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 
