Colin MacLaurin (1698-1746)
Letter to d'Ortous de Mairan. 5 February 1743
MACLAURIN, Colin (1698-1746). Autograph letter signed ('C. Mac Laurin') to Jean-Jacques d'Ortous de Mairan, Edinburgh, 5 February 1743 (Old Style).
In French. Three pages, 228 x 187mm, contemporary docket in black ink, contemporary annotation 'adresse des Paquets' on each leaf in red crayon, and limited underlining in the same hand. Integral address panel (tear at outer right corner, affecting both leaves; remnant of guard; f.2 has remnant of red wax signet seal, partially obscuring one word, and small seal tear to blank margin).
The great Scottish mathematician on his major work, the Treatise of Fluxions (1742 - see lot 106). MacLaurin thanks Mairan for a letter and several copies of his eulogy to Cardinal de Polignac, his receipt of which was delayed because 'I was in the country at that time, busy with writing a supplement to my book ... As regards my book, I expect that opinions about it will differ, especially amongs foreigners who do not perhaps know my reasons for writing in such a detailed way about the elements of the method. ... I began writing to resolve the objections of certain subtle metaphysicians, but in a treatise of this length I also wanted in some way to satisfy mathematicians, either in clarifying problems which are already known, or by dealing with some which were not well known' (translation). MacLaurin enquires after the French geodetic expedition to Peru, and reports on attempts in Scotland to 'correct the geography of the north of this island ... we will presently engrave a map of the northern part of Great Britain with the ports etc much more exact than we have previously had'; he will send a copy to Mairan in Paris. The letter concludes by advising Mairan to send any large packets in future through friends of MacLaurin's in either Boulogne (Charles Smith, merchant) or London (Sir Andrew Mitchell, under-secretary for Scotland), as he was initially asked to pay the considerable sum of 45 shillings for the delivery of the copies of Mairan's eulogy. The contemporary annotation 'adresse des Paquets' is evidently highlighting this instruction.
MacLaurin's Treatise of Fluxions (1742) is his most important work, 'the earliest logical and systematic publication of the Newtonian methods. It stood as a model of rigor until the appearance of Cauchy's Cours d'analyse in 1821' (DSB). As MacLaurin says in the present letter, the work was in part inspired by criticisms of Newton's infinitesimal calculus by Bishop Berkeley, but it went on not only to set out the fundamental principles of the calculus but also to explore its application to numerous geometrical and physical problems. The French expedition to Peru (modern Ecuador) was one of two dispatched by the Académie des sciences to settle whether the earth's circumference was greater around the equator (as predicted by Newton) or around the poles (as predicted by the Cartesian opinion then prevailing at the Académie). The parallel expedition to Lapland had reported as early as 1738 in favour of Newton, but the expedition to Peru was not to return until 1745, after many difficulties. The recipient of the letter, Jean-Jacques d'Ortous de Mairan (1678-1771) was one of the leading French scientists of his age: he is best known for his pioneering work on circadian rhythms. At the time of the letter he was 'secrétaire perpétuel' of the Académie, a post in which (in spite of its title) he served for only three years.
Autograph material by MacLaurin is of the greatest rarity on the market: according to ABPC/RBH, this is the only example to have appeared in forty years.