376 Royal Society, 



Tlie author then treats of the method adopted, to deduce the most 

 probable true mean temperature due to every day in the year ; and 

 concludes his paper by observing that there are periods of some dura- 

 tion which are very remarkable on account of the difficulty of as- 

 signing a physical cause for the anomalies apparent in the mean 

 temperature. Starting from the lowest temperature, in January, it 

 increases till the beginning of March, when, between the 3rd and 

 10th, not only is the increase checked, but there is a remarkable 

 depression of temperature. After the 10th, the increase proceeds 

 and i^ very rapid towards the end of April and the beginning of May ; 

 this rapid increase is rather suddenly checked, and followed by a 

 period of cold towards the middle of May : this period is very marked. 

 As remarkable a depression of temperature at this time of the year 

 seems to have taken place in France, having been noted in Paris 

 and at various localities, some situated near the coast ; but it does 

 not ajjpear that the equally remarkable rise at the end of April has 

 been noted. After the middle of May the numbers steadily increase 

 till the 5th of July, when they attain their maximum value. The 

 decline in the temperature towards the end of July is followed by 

 an increase at the beginning of August, after which the decline of 

 temperature is very regular till towards the end of November, when 

 a sudden and considerable increase of temperature takes place ; after 

 this the curve declines to its lowest point on the 8th of January. 



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. 



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. 



