EXPER. IX. 



TN tnoft of the Experiments that 

 X we have hitherto propofed, Cold 

 is wont to be regularly produc d in a 

 Mechanical way 3 but I (hall now 

 adde^ that in fome fort of Trials t 

 found that the Event was varied by 

 unobferv'd Circumftances 3 fo that 

 fometimes manifefl Goldnefs would 

 be produced by mixing two Bodies 

 together/ which at another time 

 would upon their Congrefs difclofe a 

 manifeft Heat 5 and fometimes again^ 

 though more rarely* would have but 

 a very faint and remifs degree of ei- 

 ther. 



Of this fort of Experiments, whofe 

 Events I could not confidently un- 

 dertake for, I found to be 5 the diflb- 

 lutionof Salt of Tartar in Spirit of 

 Vinegar , and of fome other Salts, 

 that were not acid, in the fame Men- 

 ftruum y and even Spirit of Verdi- 

 greafe (made perfe) though a more 

 C potent 



