Rowland' x Thermometers with the Paris Standard. 

 Table IV. (concluded). 

 Baudin 6166. 



17 



A. 



B. 



C. 



D. 



centim. 



centim. 



centim. 



centim. 







24-147 







611 



23-900 



24153 



•253 







24160 







590 



23927 



24171 



•244 







24183 







56-8 



23-955 



24190 



•235 







24198 







56-2 



23-980 



24-208 



•228 







24-218 







560 



24-000 



24-228 



•228 







24-238 







555 



24014 



24-245 



•231 







24-253 







535 



24-038 



24-258 



•220 







24-263 







51-6 



24-062 



24-270 



•208 







24-278 







49-8 



24-084 



24-286 



•202 







24-294 







48-0 



24-109 



24-308 



•199 







24-322 







5475 







2-248 



5475 (3 e = 2-248 cm. 



j3 e = -000411 cm. per mm. mercury pressure. 

 (3 e = 0°-000318 per mm. mercury pressure. 



6. Manner of making the Comparisons. 



In comparing a Tonnelot with one of the Baudin thermo- 

 meters, the Baudin was placed first in ice for two or three 

 hours. Its zero point was then read by means of the 

 micrometer telescope three or four times in succession, and 

 the average taken as the reading. In the meantime the 

 water in the comparison-tank having been cooled to about 

 10° or lower, the Baudin and one of the Tonnelot ther- 

 mometers were placed in the tank. The top of the tank 

 was put on, and while the box containing the bulbs remained 

 open, the water was thoroughly stirred. As long as the 

 temperature of the water in the tank was lower than that of 

 the room, it of course rose very slowly while the stirring- 

 went on. This sufficed to make the thermometers always 

 reach any given temperature below that of the room with a 

 rising meniscus. As soon as the water was thoroughly 



Phil. Mag. S. 5. Vol. 46. No. 278. July 1898. C 



