Michel ADANSON (1727-1806), botanist, explored Senegal for 5 years. Autograph letter signed "à l'ami bienfaisant du Philosophe" [Bélanger]. 3 pp. in-4. Paris, 4 February 1796 (15 pluviôse year 4). Address on the back. A very long and superb letter devoted entirely to his project for a very vast encyclopaedic publication, encompassing the 3 kingdoms of nature, which he had been advocating for 20 years and which never saw the light of day. " [...1° of the plan or method, 2° of the scope or content, 3° of the mode or manner of execution of my Universal Encyclopaedia founded on the principles of an entirely new philosophy, those of the sets of relationships of all the parts, qualities and powers of each of the 80 thousand species of existence, arranged, according to their differences, in a graduated and nuanced series, in such a way that one cannot move a single one of these existences without disturbing the order of the nuances of their differences indicated and fixed by the very nature of these existences. It is in these specific differences of the 80 thousand species of existence (limited until now to 15 or 20 thousand at most, in the most extensive catalogue of the famous Linnaeus) and of all their qualities and powers that consist the essence and the definitions of each of the hundred thousand articles of human knowledge, chosen from the 2 to 3 million of the immense fund of this universal philosophy, definitions that the wise have desired and waited for so vainly since the Prince of the Philosophers Aristotle, and whose execution could only be hoped for in a work of this scope, embracing more than ¾ of the existences of our globe. This number of hitherto unknown existences, for the most part, and certainly not thus developed in all their relations and their definitions thus nuanced and brought to a number, so to speak, immense and overwhelming for even the most extended memory, are a culminating point of knowledge at which the universal Philosopher once reached, admires nothing more, learns almost nothing more, sees only fillings, some gaps to be filled, of which the most essential are not so much the 20 or 30 thousand unknown existences (which are missing and remain to be sought and found to complete this series of 80 thousand up to the 100 thousand or so which make up our globe) as the new and useful facts or principles [?]. These are the new principles that serve as the most solid and extensive basis for the method of this universal encyclopaedic philosophy; these are the useful results of the definitions of all human knowledge, finally fixed by them 25 years ago (in 1775) when I read the very detailed plan on 15 February 1775 in 18 pages in-4° at the Academy of Sciences, and which was printed with the report of its commissioners in 4 pages [...]. It would be essential for you and your esteemed and benevolent friends to come one day, or even immediately, after our philosophical lunch, between 3 or 4 o'clock at the latest, to take at least a 1st look at this 30ne of more general articles of this Encyclopaedia, on the unique collection of 80 thousand figures, on the suites, as complete as they are precious for their notes, of the objects in his cabinet, his numerous articles added and corrected on the famous Encyclopaedia of the genius Diderot. So here I am at the dawn of this beautiful day which should bring me together, on this globe, in the happy abode of beneficent friendship, with the esteemed talents of these men as virtuous as they are enlightened and benevolent protectors of the septuagenarian philosopher, and make him enjoy, for the 1st time, the happiness he sacrificed and lost by occupying himself all his life with the happiness of the whole of humanity! [...] " [On 15 February 1775 Adanson submitted to the Académie des Sciences the plan for an immense work covering all known beings. It consisted of 27 large volumes explaining the relationships between all entities; there were one hundred and fifty additional volumes devoted to 40,000 species, a glossary of 200,000 words, special memoirs, 40,000 figures and 30,000 specimens from the three kingdoms of nature. A committee strongly advised Adanson to publish separately all that was his own work, leaving aside what was merely a compilation. Adanson stubbornly rejected the advice, and the work, which he continued and to which he devoted his resources, was never published. At the time, the young but ambitious Antoine-Laurent de Jussieu, nephew of Bernard de Jussieu, considered the classification proposed by Adanson to be a copy of that proposed by his uncle, whereas it was rather the result of their past cooperation; however, Adanson's work had just paved the way for his own, Genera plantarum (1789)].