58 Vegetable Statkks, 



and trees, in proportion to the greater or lefs 

 convergency of the Sun's rays. 



The learned Boerhaave, in his 'Theory of 

 Chemiftry, Dr. State's Edition, p. 245. ob- 

 ferves, " That thofe white clouds which ap- 

 * c pear in fummer-time, are, as it were, fo 

 " many mirrors, and occafion exceffive heat. 

 Ci Thefe cloudy mirrors are fometimes round, 

 <£ fometimes concave, polygonous, &c. When 

 cc the face of heaven is covered with fuch 

 " white clouds, the Sun mining among 

 cc them, muft of neceffity produce a vehe- 

 u ment heat 5 fince many of his rays, which 

 cc would other wife, perhaps, never touch 

 " cur earth, are hereby reflected to us -, thus* 

 ci if the Sun be on one fide, and the clouds 

 cc on the oppofice one, they will be perfect 

 a burning- glaffes. 



<c I have fometimes (continues he) ob- 

 rc ferved a kind of hollow clouds, full of 

 ci hail and fnow, during the continuance 

 ?' of which the heat was extreme; fince by 

 < c fuch cendenfation they were enabled to 

 " reflect much more ftrongly. After this 

 ci came a fharp cold, and then the cloud s 

 " difcharged their hail in great quantity ; 

 u to which fucceeded a moderate warmth. 



" Frozen 



