250 Natural History, [Chap. III. 



means of the equation formed by the philosopher 

 of Goettingen, but rendered much plainer and 

 more simple, he has calculated the mean annual 

 temperature of every degree of latitude between 

 the equator and the pole. He has also calculated 

 the mean monthly temperature of that part of the 

 ocean which lies between the eightieth degree of 

 northern and the forty-fifth of southern latitude, 

 extending westward as far as the Gulf Streamy 

 and to within a few leagues of the coast of Ame- 

 rica ; and for all that part of the Pacific Ocean 

 reaching from 45'^ north to 40° south latitude, and 

 from 20 '^ to %15^ east longitude. This immense 

 tract of ocean he calls the standard. From these 

 calculations he has deduced a number of important 

 principles of great practical utility, and which 

 place him among the most distinguished meteoro- 

 logists of the eighteenth century. 



The origin, qualities, and laws of Winds have 

 been diligently studied during the period under 

 consideration, but not with the same success that 

 has attended inquiries into other branches of me- 

 teorology. No satisfactory theory has yet been 

 formed on this subject ; owing to the want of ob- 

 servations, sufficiently numerous, of the exact times 

 and places where they begin and cease to blow, 

 but chiefly to our imperfect knowledge of the 

 means by which great regions of air are either 

 suddenly produced or destroyed. The discoveries 

 of modern chemists evince that air is perpetually 

 subject to increase and diminution, from its com- 

 bination with other bodies or its evolution frorn 

 th'^m : and, therefore, that a just theory of winds, 

 whenever it shall be formed, will be found to rest 



