444 1'HILOSOFHICAL TRANSACTIONS. [ANNO 17S3. 



Quebec, from the year 1743 to 1749, an extract from which is inserted in the 

 Memoirs of the French Academy of Sciences. The account given of his ther- 

 mometer is too indefinite to allow any certain inference to be drawn; but as the 

 quicksilver several times contracted so much as to leave a visible vacuity in the 

 top of the bulb, and the scale seems to have reached near to its point of conge- 

 lation, it is rather probable that it actually froze. If so, Quebec, situated in 

 lat. 47°, is the most southern place in which such a great degree of natural cold 

 has hitherto been observed. 



We come now to an instance of what, however often it may have happened, 

 has hitherto never been suspected, the congelation of quicksilver in Europe by 

 natural cold. The observations which prove this fact are recorded in the Trans- 

 actions of the Royal Academy of Sciences at Stockholm, whence Dr. B. has ex- 

 tracted the following account. In January 1760, the weather was remarkably 

 cold in Lapland. On the 5th of that month different thermometers sunk to — 

 76°, — 128°, or lower. Again, on the 23d and following days, they fell to — 

 58°, — 79°, — 92°, and below — 238° into the ball. This great descent of the 

 mercury was observed in 4 places, Tornea, Sombio, Iukasierf, and Utsioki, all 

 situated between the 65th and 70th degrees of n. lat. and the 21st and 28th of 

 eastern longitude, by M. Andrew Hellant, economical inspector of Lapland, 

 whose remarks on the phenomenon afford of themselves sufficient evidence, that 

 the quicksilver was frozen. 



Several reflections present themselves on the perusal of his observations. The 

 phenomena fairly show, that there was a sufficient degree of cold to congeal the 

 quicksilver in Mr. Hellant's thermometers, which sometimes sunk regularly into 

 the bulb, but commonly stuck fast in the tube till it was heated by the sun, the 

 fire, or a warm room, and thus made to subside. The continuance of this cold 

 was very remarkable; it lasted no less than 3 days, with sufficient intensity to 

 freeze mercury; a circumstance almost unparalleled any where, and the more 

 extraordinary, because M. Hellant, during 23 years that he had made observa- 

 tions in Lapland, never before saw the thermometer so low as to indicate a con- 

 gelation of the mercury. But it was not in Lapland alone that the season was 

 uncommonly severe. At this same time the frost was nearly, if not quite, in- 

 tense enough at Petersburg to freeze quicksilver, as appears from the remarks of 

 M. Braun, who was then engaged in his experiments. And it is a curious coin- 

 cidence of events, that on the very day when the congelation of mercury by ar- 

 tificial means was first clearly established in Russia, Nature should be performing 

 the same operation before the eyes of an attentive and philosophical observer in 

 a neighbouring kingdom, who yet had not sufficient sagacity to divine her secret. 



Early in the spring. of 1761, the Abbe Chappe D'Auteroche, in his journey 

 to Tobolsk for observing the transit of Venus, passed through Solikamsk, a 



