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2. " On the periodic and non-periodic variations of Temperature 

 at Toronto in Canada from 1841 to 1852 inclusive." By Colonel 

 Edward Sabine, R.A., Treasurer and Vice-President of the Royal 

 Society. Received 20th Jan. 1853. 



The principal object of this communication is to make known the 

 non-periodic variations of temperature for every day in the twelve 

 years, from 1841 to 1852 inclusive, at Toronto in Canada. The non- 

 periodic variations are those differences of the temperature from its 

 mean or normal state which remain after all the known periodical 

 variations are allowed for, and are such as are generally accompanied 

 by peculiarities of wind or of other meteorological circumstances. 

 Recent investigations have led to the inference that opposite condi- 

 tions of weather prevail simultaneously in the same parallels of lati- 

 tude under different meridians, and that in particular Europe and 

 America usually present such an opposition, so that a severe winter 

 here corresponds to a mild one there, and vice versd\ and recent 

 theories of the distribution of heat on the surface of the globe pro- 

 fess to furnish the explanation. To place the facts on indisputable 

 ground, it is requisite that a comparison should be made of unex- 

 ceptionable records of the non-periodic variations in Europe and 

 America, continued for a sufficient time to afford a proper basis for 

 inductive generalisation. Toronto, from its latitude 43° 40' N. and 

 inland situation, is well suited to supply such a comparison with 

 stations in the middle parts of Europe where similar records have 

 been kept; and the twelve years embraced by the observations, viz. 

 1841 to 1852, have been years of unusual meteorological activity in 

 Europe. 



Details are given in the commencement of the paper showing the 

 care bestowed on the examination of the thermometer employed, 

 with a standard divided " a Vechelle arhitraire," by the method of 

 M. Regnault ; as well as the precautions adopted for its fair ex- 

 posure, and for its protection from rain and radiation. The obser- 

 vations were made by the non-commissioned officers of the detach- 

 ment of the Royal Artillery employed in the duties of the obser- 

 vatory. 



The period of twelve years comprises two series, in one of which the 

 thermometer was observed hourly, and in the other less frequently, 

 each observation in the second series receiving however a correction 

 to the mean temperature of the day furnished for every hour and 

 every day of the j^ear by the first series. The two series, each of 

 six years, are separately discussed ; from the first series equations 

 are derived from the mean monthly temperatures by the method 

 suggested by Bessel (Astron. Nach. No. 136), whereby the most 

 probable values of the temperature, on every day and every hour, 

 are computed corresponding to the whole body of the observations. 

 These the author regards as approximate normal values, and by 

 comparing with them the actual daily temperatures, — which in the 

 first six years are the means on each day of twenty-four equidistant 

 observations, and in the second six years the means of all the obser- 

 vations made on each day, each observation having been corrected 



