Desirable as the salary would have been in his straitened circumstances, he modestly refused the offer, because he felt unable at that time of life (he was, however, but sixty-five years of age) to make the studies required worthily to occupy the position.
One of Lamarck's projects, which he was never able to carry out, for it was even then quite beyond the powers of any man single-handed to undertake, was his _Systeme de la Nature_.

We will let him describe it in his own words, especially since the account is somewhat autobiographical.

It is the second memoir he addressed to the Committee of Public Instruction of the National Convention, dated 4 vendemiaire, l'an III.

(1795): "In my first memoir I have given you an account of the works which I have published and of those which I have undertaken to contribute to the progress of natural history; also of the travels and researches which I have made.
"But for a long time I have had in view a very important work--perhaps better adapted for education in France than those I have already composed or undertaken--a work, in short, which the National Convention should without doubt order, and of which no part could be written so advantageously as in Paris, where are to be found abundant means for carrying it to completion.
"This is a _Systeme de la Nature_, a work analogous to the _Systema naturae_ of Linnaeus, but written in French, and presenting the picture complete, concise, and methodical, of all the natural productions observed up to this day.

This important work (of Linnaeus), which the young Frenchmen who intend to devote themselves to the study of natural history always require, is the object of speculations by foreign authors, and has already passed through thirteen different editions.