44 ©ft|>e^ec|)amtal^tgme 



?ir and water be mov'd never lb ye* 

 hemendy, as in high Winds and Ga- 

 taradk, yet we are not to, exp€$ 

 that they fhould be manifeftly hot* 

 becaufe the vehemency belongs* to 

 the progreffive motion of the whole 

 body 5 notwithftanding which, the 

 parts it confifts of may not be near 

 fo much quickned in their motions 

 made according to other determina- 

 tions , as to become fenfibly hot. 

 And this Confideration may keep 

 it from feeming ftrange^ that in fome 

 cafes 5 where the whole body, though 

 rapidly moved, tends but one way, 

 'tis not by that fwift motion percei- 

 ved to be made Hot. 



Nay, though the agitation be very 

 various as well as vehement , there is 

 yet a third Condition required to 

 make it Calorific ^ namely., that the 

 agitated particles , or at leaft the 

 greateft number of them, be fo mi- 

 nute as to be fingly infenfible. For 

 though a heap of fand or duft it felf 

 were vehemeatly and confufedly a- 

 gitated by a whirIwind D the bulk of 



the 



