THE 



EDINBURGH NEW 

 PHILOSOPHICAL JOURNAL. 



On the Diminution of Temperature with Height in the Atmo- 

 sphere, at different seasons of the year. By James D. 

 Forbes, Esq. F.R.SS.L. &E., Professor of Natural Philo- 

 sophy in the University of Edinburgh.* 



In the year 1830, I succeeded in establishing a Register of 

 the Thermometer at the Bonally Reservoir, which formerly 

 supplied the city water-works, being at a distance of five miles 

 in a direction south-west from Edinburgh. This station is on 

 the northern acclivity of the Pentland Hills, at a height of 

 1100 feet above the sea. The following year I obtained cor- 

 responding observations at the village of Colinton, situated a 

 mile and a half north of the preceding station, and above 700 

 feet lower. Although this difference of level be not very con- 

 siderable, yet, as these comparative registers have been kept 

 for nearly five years with pretty uniform results, some confi- 

 dence is evidently due to the conclusions, even although consi- 

 derable difficulties opposed themselves to obtaining registers 

 quite free from exception. The interest attaching to them is 

 the greater, that, although registers have been kept at Lead- 

 hills and other elevated stations, I do not recollect any strictly 

 comparative observations in Scotland, perhaps not even in 

 Great Britain, at two stations near one another, and differing 

 considerably in level, from which the important meteorological 

 element of the decrement of temperature in the atmosphere 

 could be deduced. 



* From Transactions of tho Royal Society of Edinburgh, vol. xiv. ; read 

 1st April 1839. 



VOL. XXIX. NO. LVIII.— OCTOBER 1840. F 



