OF THE GLOBE. 



209 



oflen occasion a difference of temperature under the same la- 

 titude. In the case of Edinburgh, for example, the mean 

 temperature, deduced from Mr Playfair's observations, is 

 47.8*, differing considerably from the formula, while the 

 VOL. IX. p. I. D d mean 



* As Mr Playfair's observations were made in Windmill Street and Buc- 

 cleuch Place, where the thermometer must have been influenced by the heat reflect- 

 ed from the opposite sides of these streets, I consider the mean of his annual tem- 

 peratures, viz. 47°.8, as erring in excess, and have therefore preferred 46*.23, the 

 result of Messrs Milleb and Adie's observations. 



This opinion respecting the temperature of Edinburgh is strongly confirmed 

 by the following valuable and accurate observations, made and communicated to me 

 by my friend Mr James Jardine. 



Temperature of the Crawley Spring, situated 564 feet above the level of 

 the sea. 



1811, 30th January, - 46'.5 Fahrenheit, 



21st March, - 46.0 



18th April, - 46 .2 



19th August, - 46 .7 



Mean, 46.35 

 Add for 334 feet above Merchant Court, 1.00 



Mean Temperature at Edinburgh, 47 .35 



Temperature of the Black Spring, situated 882 feet above the level of the sea, 



46.81 



Mean 



