(20) 9 avril 1737 : Celsius (Torneå) écrit à Mortimer :
I hope you have received the letter which I had the honour to write you a month since. At present I trouble you with two enclosed, and beg you'll desire M[onsieu]r Graham to answer my letter as soon as possible. You'll oblige me likewise in speaking a word to Dr Halley, when you give him my letter, concerning his tables which he promised me. We now returned from Pello for the second time [le 14 avril [cf. 14 avril 1737 (1)]]. On the mountain Kittis, the other end of our meridian, we observed the star α Draconis with M[onsieu]r Graham's instrument [le 4 avril 1737], and are quite satisfied with our observations. And I dare venture to assure you, that our measurment of a degree has a geometrical certainty. At Pello we likewise made several experiments with pendulums and chiefly with that of M[onsieu]r Graham's make. M[onsieu]r Maupertuis was at the pains of keeping up the same degree of heat in his chamber during five subsequent days, for the pendulums : a thing very difficult to be done in this country, where the thermometer at present changes in one day, above twenty degrees. Upon our leaving Pello, I went nine swedish miles farther North, to see a monument, which is said to contain an inscription in unknown characters. For so doing, I was obliged to pass three miles thro' a forest, in which there is neither road nor house, in a very troublesome and even dangerous carriage : that is in a small sledge made like a boat drown by Ren[n]e Deer. In this machine one must be well acquainted with the method of keeping an exact poise : otherwise one runs the risk every moment of breaking a leg, arm, etc., when the deer runs swift amoung the trees. Il found the stone, with some lines cut into it, which to me seen to have no signification. However, I will send you a copy of them by some other opportunity, in order to communicate it to the society of antiquaries. Thus is our work at an end : and we only wait for the melting of the ice, which shuts up the rivers and sea coasts to the beginning of June. Winter is still in its rigor here, especially at nights. The ground is quite covered with snow three or four feet deep. The thickness of the ice on the lakes, rivers, and the edges of the Sinus Bothnicus, is about two feet. All the cataracts, except some of the most rapid, are frozen. We had drowings taken of many of the birds of this country. The ermins, hares and those birds called ripa, are already changed from white to brown. I beg you'll pay my respects to Sr Hans Sloane, and all the others, whom I have the honour to be known to [...] and am with perfect esteem [...]. [PS] M[onsieu]r Maupertuis makes you his compliments, and joins with me in urging M[onsieu]r Graham's answer (Nordenmark 36, pp. 74-75).
Courcelle (Olivier), « (20) 9 avril 1737 : Celsius (Torneå) écrit à Mortimer », Chronologie de la vie de Clairaut (1713-1765) [En ligne], http://www.clairaut.com/npo20pf9avril1737.html [Notice publiée le 13 décembre 2008].
