On the Temperature of the Atmosphere at Fort Simpson. 125 



two hours as giving very nearly the true annual mean. Having 

 found, also, by consulting a considerable number of North 

 American registers of temperature, that the hourly curve for 

 September falls always between that of May and August, and 

 generally somewhat nearer to the former than to the latter, 

 I have supplied the defect of observations for that month by 

 assuming + 48° F. as its mean heat. 



The thermometer employed was a spirit one made by Carey, 

 which, when compared with several constructed by Newman, 

 was found to keep nearest the mean of the whole. No cor- 

 rection has been made for the diminishing contraction of the 

 spirit at low temperatures. 



Abstract of the Thermometrical Register kept at Fort Simpson for 

 one year 1837-38. (The temperature for September interpolated. J 

 (Spirit Thermometer by Carey. Fahr. Scale.J 



