404 ESSAYS and OBSERVATIONS 



the aeidum vagum, which it has imbi- 

 bed. 



Seeing therefore the fak of Hartfcll 

 fpaw has all the properties of vitriolmn 

 Martist I cannot fee why it may not be 

 allowed that this fpaw contains a native, 

 fixed vitriol of iron : And it is the only 

 water (I know of) which has been dif- 

 covered to contain fuch a fait. 



In the Philofophical Tranfa(5lions, No. 

 245*. mention is made of two mineral wa- 

 ters, which yielded a real fixed vitriol of 

 iron, one near Eglingham in Northum- 

 berland, the other near Haigh in Lanca- 

 ihire; but thefe waters were found by 

 Dr Cay, who made particular inquiry into 

 the matter, not to be mineral fprings, but 

 drifts made for the draining of coal-pits ; 

 and that the vitriol found in thefe waters 

 was owing to their running over marca- 

 fite beds, which had been expofed for fome 

 time to the air. I was fufpicious that 

 fomething of this kind had communi- 

 cated the, vitriol to the Hartfell fpaw -, 

 but Mr Williamfon, who difcovered the 

 fpring, alTured me, that the water, on 



which 



