13i2 Chemical Pkilosopky, [Chap. II. 



alcohol. His plan was, of course, still far from 

 being perfect. The thermometer now in use in 

 France, and through a great part of the continent 

 of Europe, under the name of Reaumur's, ought 

 strictly to be called Mr. de Luc*s, who made a 

 very important alteration in M. Reaumur's mode 

 of graduating the instrument, and again exchanged 

 alcohol iov mercunj. In 173.'i M. de I'lsle, of Pe- 

 tersburg, constructed a mercurial thermometer, 

 which is generally used in Russia. Another, gra- 

 duated in a different manner, by Celsius, and 

 also filled with mercury, is most popular iu 

 Sweden *. 



Beside these leading inventions and involutions 

 which the history of thermometers presents, the 

 plans which have been suggested in modern times, 

 for improving this instrument, are many and in- 

 genious. These have been successively proposed 

 by lord Cavendish in 1151 , by Mr. Six in. 1782 j 

 hy Dr. Rutherford m 1790; and still more recently 

 by Mr. Keith, whose new self-registering thermo- 

 meter is said to be the most ingenious, simple, and 

 perfect, of all that have hitherto appeared. 



It was still, however, an important desideratum, 

 to fmd some easy and exact method of measuring 

 very high degrees of heat. Such a method was 

 not long since invented by Mr. Wedgwood, of 

 Staffordshire, a gentleman well known for his 

 great improvements in the art of pottery. After 



- See Dr. Martliie's Essay on the Construction and Graduation 

 of Thermometers; one of the best works extant on this subject. 

 Mr. de Luc, of Geneva, and professor van Swindcn, of Francker, 

 have also written ably and instructively concerning Tiierxno- 

 meters. 



