3^8 ESSAYS AND OBSERVATIONS 



ances, can only be deceriiined from ex- 

 periment : Wherefore I diffoh ed in wa- 

 ter a gr^^ater proportion of alum than 

 there is or feems to be, in this fpaw ; 

 and, when equal quantities of this folu- 

 tion and f reili milk were boiled- together, 

 the milk did not curdle. 



* 



6. This water contains very little 

 earth, it gives not the leaft fign of it, when 

 oL tart, p, d. is dropt into it ; but the lit- 

 tle it contains feems to be of the white 

 calcarious kind : And though okry earth 

 is commonly allowed to be a conltituent 

 principle in chalybeate waters, yet I am 

 ,of opinion, that no fuch thing exifts in 

 them in a found, natural ftate ; and that 

 it is never to be found till the acid, or 

 •whatever it is that diflblves the iron-prin- 

 ciple, leaves the water, or, at leaft, its u- 

 nion with the iron- principle, then it ap- 

 pears in the form of an okry fubftance ; 

 but, while the difTolvent of the chalybe- 

 ate principle reaiains united to it, that is, 

 as long as the water continues in a found 

 ftate, okry earth is never to be found in it. 



The 



