4V2 ON THE CLIMATOLOGY OF STRATFORD, ONTARiO. 



above T; T^ and /\^ analogous quantities for Stratford. Then 



approximately _i =: tjj and therefore Ai =f X T^. /\ and Tare 



known from the Toronto records, Tj from Stratford; and therefore /\^ is 

 known approximately; consequently the July temperature for the spe- 

 cified hour = Tj 4" Ai i^early. Tlie observation hours at Toronto not 

 being the same as at Stratford, the mean of 6 and 8 a.m. was used for 

 7 A.M., 2 P.M. for 1 P.M., and 10 for 9 p.m. 



It is not strictly correct to assume that the above plan will give the 

 true mean temperatures at Stratford for July, 1863-'64 ; but as the 

 error in the niac-year mean will be probably small, the advantage of 

 utilising the observations taken during the remaining months of these 

 years will overbalance any slight departure from strict accuracy in the 

 July temperatures. 



From the nine years' mean for each hour, and for the three hours 

 combined, the following formulae are derived, in which i represents the 

 temperature fur that hour on any proposed day, and x an angle proper, 

 tional to the number of days from January 15th : 



7 A.M. 



t = 39°.52 -f- 22°.4G sin (x+261° 25') + 1°.22 sin (2 x + 142° 0' 

 + 0°.51 sin (3 cc + 217° 47') + 0°.37 sin (4x4- i^° 55') 

 + 1°.08 sin (5 X + 350° 58') — 0°.14 cos 6 x. 



1 P.M. 



i = 47°.G7 + 25°.45 sin (x + 263°.23) -f- 0°.21 sin (2 x + 119° 3') 

 4- 0°.25 sin (3 X + 182° 18') + 0°.38 sin (4 x + 60° 4') 

 + 0°.95 sin (5 X + 357° 35') — 0°.26 cos 6 x 



9 P.M. 



t = 41°.88 + 22°.41 sin (x + 262° 38') + 0°.52 sin (2 x -f 137° 21') 

 + 0°38 sin (3 X + 234° 38') + 0°.43 sin (4 x -[- 30° 44') 

 4- 0°.9l sin (5 X + 342° 45') — 0°.18 cos 6 x. 

 Theee-hour Means. 



f = 43°.02 -f 23°.44 sin (x + 262° 31') + 0°.64 sin (2 x + 138° 49') 

 + 0°.36 sin (3 x -f 215° 55') + 0°.39 sin (4 x + 43° 57') 

 + 0°.97 sin (5 X + 350° 32') — 0°.19 cos 6 X. 



From these formulae, tables have been constructed of the normal 

 temperatures at the hours 7 A.M., 1 p.m., and 9 p.m., and of the normal 

 means for the three hours combined. Of the four tables constructed, 

 the latter only is here shown. 



