Observations of Temperature. 167 



extend is short, the results were definite, and suggested 

 several matters to which our attention will have to be 

 directed in future. 



The remarkable differences which appear in the tem- 

 perature records in different parts of the city furnish an 

 additional proof, if proof were wanted, that observations 

 taken in or near a large town cannot be taken to represent 

 correctly the meteorological character of the surrounding 

 districts, but it by no means follows that these observations 

 are of no value. On the contrary, they may lead to some 

 important conclusions on what may be called town weather 

 as distinguished from country weather. 



It seems to me that the differences in the minimum 

 temperatures are accounted for by the fact that the smoke 

 hanging over the city prevents a free radiation into space at 

 night. The smaller the amount of dust and smoke the 

 lower would be the minimum temperature. The effect of 

 smoke is so considerable that the differences between the 

 Oldham Road and Whitworth Park observations amount, 

 as Mr. Wilson has shown, in some cases to 1 1 degrees, and 

 it would be interesting to have some records still nearer the 

 centre of the city. 



The lessening of cold in winter nights might not seem at 

 first sight to be an object for regret, but it must be remem- 

 bered that the same cause which shelters the town against 

 the effects of radiation, will prevent the sunlight from having 

 its due effect in daytime. Consequently, in the month of 

 January, Oldham Road only registered 62^ of the sunlight 

 registered at Whitworth Park ; and here it must again be 

 remembered that the Oldham Road Observatory is not 

 near the centre of the city, nor is the Whitworth Park very 

 far removed from it. How much greater, then, may we 

 expect to find the differences existing between the centre of 

 the town and the country. 



The effect of smoke seems so considerable, and its 



