«o8 Curfory View of 



ing together thefe two fofiils, and making them only on* 

 fpecies *. 



XVII. Curfory View offome of the late Di/'coveries in Science* 

 [Continued from the laft Number, p. 65.] 



Meteorology. 



M, 



■ETEOROLOGY, which depends only on an immenfe 

 number of obfervations, has, however, been exalted into a 

 fcience. It affords general refults of great importance; a 

 collection of whic l ^en made by Cotte. By thefe it ap- 



pears that the barometer varies very little under the equator. 

 Its variation becomes greater in proportion as it approaches 

 the poles. It feems to experience a diurnal and an annual 

 variation. 



Diurnal variation. — Between the hours of ten and two, 

 both of the day and the night, the rifings and fallings of the 

 mercury are the leaft. The contrary takes place between 

 the hours of fix and ten of the morning and evening. This 

 feems to depend on the fun and the moon pafling the zenith. 



Annual variation. — The ofcillations are lefs in fummer, 

 greater in winter, and very great at the equinoxes. This 

 feems to depend, like the tides and the winds, on the fame 

 aciion of the fun and the moon. 



Thermometer s .—-The mean degrees of heat are almoft the 

 fame in all latitudes. Kirwan has given a table for calcu- 

 lating the mean degrees of heat in different latitudes. 



Rains are more frequent in winter than in fummer; more 

 abundant in fummer than in winter. Mean quantity of rain 

 at Paris twenty-two inches. The evaporation generally ex- 

 ceeds the rain at Paris. The mean evaporation is thirty- 

 three inches. 



Aurora hnrealis is more frequent about the time of the 

 equinoxes than at any other feafon. This phenomenon is 



• : Sec Abbe Haiiy on Cryftallifationf. 



almoft 



