[ ^6 ] 
in the hate of an aqua magiftra aluminis £? vitrioli , 
incapable of cryftallization. 
The Someriham water, therefore, feems to differ 
.coniiderably from any of the mineral waters known 
in Great Britain or Ireland *. For among the writers, 
who even admit and mention aluminous waters, no 
one, except Dr. Short, pretends to have feparated 
cryftals of ahum from them ; and even he declares, 
that in fubfequent trials on the Nev.il Holt water 
(from which he had once obtained fome) he could 
.not lucceed. 
Though if we confider that allum is compofed of 
the vitriolic acid, united to an argillaceous earth, it 
v/ill not be difficult to conceive that an acid water, 
paffing through a hratutn of fuch earth, fhould adt 
upon, and unite with a fmall portion of it ; or the 
water may diffolve fome allum in the ffratum of de- 
compofed pyrites, where it is impregnated with iron 
and felenite. So that probably allum has been often 
overlooked in water wherein it exifted ; nor did we 
obtain any in our experiments, until nearly all the fe- 
lenite had been feparated. 
However, as allum is a very powerful medicine ; 
the quantity difeovered in the Somerfham water, muff 
have contributed not a little to its efficacy, in fome of 
the remarkable cafes wherein you have obferved its 
fuccefs. 
I am, 
S I R, 
Your obliged humble Servant, 
Michael Morris. 
* Rotty' Syrropfis of Mineral Waters, p. 299. Lucas Eflay 
-cn Waters, Vol. II. p. 24. 
1 IV. Account 
