TEMPERATURE AT HALIFAX, NOVA SCOTIA. 



27 



insufficient continuance. It is with the former class of corrections that 

 this article is concerned. 



Mr. Allison has forwarded to Toronto for reduction a series of ther- 

 mometric readings, made by him or under his direction at every even 

 hour (with a very few exceptions) during the three years 1867-69. 



In a few instances, when readings at 2 a.m. and 4 a.m. were not 

 taken, the observations of the whole day were set aside. As these, 

 including Sundays, were only 22, the unbroken days in the three years 

 amounted to 1,074, and the readings employed in the calculation 

 12,888 ; giving, for each month, 80 or 90 readings for each of the 

 twelve bi-hourly means. 



The primary object of the computation being to learn for each 

 month the quantity by which the temperature at each hour differs 

 from the mean temperature of the month for all hours collectively, 

 interpolating formulae for each month have been constructed, by aid of 

 which the most probable temperature could be computed for any 

 instant in the twenty-four hours. 



The following is the general type of the formula3,yhere T^ represents 

 the required temperature at any time (n) reckoned from midnight, the 

 unit of time being one hour, t , ti, tz, &c., certain constant tempera- 

 tures, and Cj, c,, &c., certain constant angles derived from the twelve 

 bi-hourly mean temperatures for the particular month under consi- 

 deration. 



T^ = t^-\- t^ sm(nX15 + ''i)+ ^^ sin (2 ?i X 15 + ^^2) + ^3^^° {^ny^\%-\-c.) 



-f t^ sin (4n X 15+cJ + t. sin (5 ?i X 15 + ^5) + t^- sin (6 « X 15 + Cg) 



The values of the constants ^„, t^, &c., c,, Co, &c., are given for each 

 month in the following table. 



TABLE I. 



