164 
ON THE TEMPERATURE OF TORONTO. 
line its actual march, and their difference the non-periodic variations for intervals of 
five days. The monthly means are distinguished by a small circle drawn around the 
point which marks the temperature ; they are connected by faintly dotted vertical 
lines with the monthly means (similarly distinguished) of the normal temperatures of 
the latitude of Toronto, derived by Dove from the mean monthly temperatures of 
thirty-six equidistant points in each of the parallels of 40° and 50 as shown b} his 
isothermal maps. The normal temperature corresponds to the level of the sea ; the 
temperatures at Toronto are those given directly by the observations, uncorrected 
for the elevation, which, as already stated, is about 342 feet above the sea. 
