304 



LIGHT, HEAT, 



Sect. XIII. 2. 2 



very cold ones, as water when frozen lofes fuddenly a part of its 

 combined heat, at the moment it becomes ice. 



2. It is evident, that without fluidity the blood or juices can not 



stable veflels ; whence fo great a dimi- 



b 



f heat as to produce froft on this account would defiroy them 



if Ion 2" continued 



o 



the fame tim 



tj 



dedudion of 



IS 



known to deftroy the irritability of animal as wel] as of vegetable 

 fibres, and muft on this account alfo prevent the circulation of their 



fluids, and occafion the mortification of parts of th 



f the whole. But when fluid 



ted 



)r the death 

 the bulk of 



; 



them is enlarged to a confiderable degree, and that with fuch vio- 

 lence as to burfl iron veflTels, as bombs, which are filled with water. 

 Whence in this manner alfo froft deftroys thofe parts of vegetables, 

 which are moft fucculent ; as the early (hoots of a(h trees, and other 

 young plants,, are frequently defl:royed in the beginning of May by a 

 frofl:y night. 



Th 



e 



flels of thefe fu 



parts of pi 



are diflended 



d 



burfl by the expanfion of their frozen fluids j while the drier or more 

 reflnous vegetables, as pines, yews, laurels, and other evergreens, are 

 lefs liable to injury from cold. The trees in valleys are on this 



ac- 



more liable to Injury by the vernal frofts, than thofe on em 



becaufe their early fucc 



flioots appear fooner in th 



year. 



Another method, by which the acl of freezing may defl;roy vege- 

 table life, may be by feparating fome part of their fluids from other 

 parts of them. Thus when wine, or vinegar, or fait and water," or 

 clay difFufed in water, and perhaps milk, are frozen ; the watery 

 part, as it congeals, protrudes from its forming cryftals the fpirit, the 

 acid, the fait, the clay, and probably the opake particles of the milk ; 

 and by a fimllar procefs on vegetable and perhaps on animal fluids, 



mi 



when expofed to great cold, they may be rendered unfit for future 

 circulation or life. See Se6l. XV. 4. i. 



The 



