Thermometers. 



Iv 



the abstracts of results, the reading of the wet bulb has been considered the same 

 as that of the dry bulb. 



91. In January 1843, a series of comparisons of different thermometers, in water 

 of different temperatures, was made with a standard thermometer by Newman : 

 the results are given in the Introduction for 1843, Table 23, p. Ivii. The readings 

 of the standard, and the dry and wet bulb thermometers, in a mixture of pounded 

 ice and water, at the time of the comparisons in 1843, and in 1845 and 1846, are as 

 follow : — 



Jan. 7, 1843. Newman's standard, 32°-00. 



Feb. 8,1845 32°-05. 



Feb. 13, 1846 32°-12. 



Dec. 18, 1846. 



Dry bulb, 32°-7. Wet bulb, 32°-6 



32°-8 32°-65 



32°-9 32°-7 



32°-9 32°-7 



It appears, therefore, that the index errors of the dry bulb thermometer were 

 about two-tenths of a degree greater in 1845 and 1846 than in 1843, and the index 

 errors of the wet bulb, about one-tenth of a degree greater ; making allowance for 

 this change in Table 23, Introduction for 1843, we obtain 



Table 11 — Corrections of the Dry and Wet Bulb Thermometers to the 

 Temperature by Newman's Standard, in 1845 and 1846. 





Corrections. 





Corrections. 



Tempera- 

 ture. 





Tempera- 

 ture. 















Dry. 



Wet. 





Dry. 



Wet. 



o 



o 



o 



o 



o 



o 



32 



-0-9 



-0-7 



60 



-0-6 



-0-4 



36 



-0-8 



-0-6 



63 



-0-5 



-0-3 



40 



-0-8 



-0-6 



67 



-0-3 



-0-1 



45 



-0-7 



-0-5 



70 



-01 



-I-0-2 



50 



-0-6 



-0-4 



76 



00 



-FO-2 



55 



-0-6 



-0-4 



79 



-0-1 



-hO-2 



On December 18, 1846, the standard and dry and wet bulb thermometers were 

 compared in water : — 



Standard, 58°-8. Dry bulb, 59°-3. Wet bulb, 59°-l. 



Correcting the standard reading for its index error of 0°-l, the corrections for 

 the other thermometers near 60° are 



Dry bulb - 0°-6. Wet bulb - 0°-4. 



The following corrections were obtained from comparisons with the standard in 

 the external atmosphere : — 



1845. Jan. 30. The correction for the dry bulb thermometer at a temperature of l°-5 = — 0°-3. 



1846. June 3. The correction for the dry bulb thermometer at a temperature of 825= —0-15. 



