[ 483 J 
frequently taken large quadrilateral cryftals of this, 
laffc mentioned fait out of the cifterns in which a 
iirong lixivium of green vitriol had been fet to- 
cryftallize at the copperas works near Whitehaven. 
And here it may be proper to remark, that the 
large beds of freeftone found in the coal-grounds 
near Whitehaven, and in mofl other places where 
there are veins of coal, though fuch (lone is often' 
very hard when dug out, and does not (eem liable to 
decay while lodged deep in the earth, yet will Sel- 
dom endure the weather; but, whenexpofed to the 
open air, gradually moulders into duft, and is there- 
fore unfit for buildings. W hich decay of thefe 
ftones feems owing chiefly to the germination of this 
bitter fait, and fometimes alfo to that of vitriol ; 
but feldom to the formation of nitrous falts, as has 
been mofl commonly fuppofed. 
Partition II. N° 2. Bitter fait, from the fame col- 
liery, in a concreted form, found lying in fmall va- 
cuities towards the top of fome large pillars of coal, 
there left about forty years ago, to fupport the roof 
of the mine. The fait has been generated from the 
whitifh grey freeftone, of which this roof is formed, 
and feems compofed of many fmail filaments (the fame 
as N° 1.), that have gradually (hot out from their 
ftony matrix fo clofe to each other, as to unite into 
one folid mafs. 
N. B. Various other kinds of falts, formed by 
germination, afiume this fibrous texture, in like 
manner with this bitter fait, as will appear from the 
fpecimens of green vitriol and alum here exhibited, 
which I collected from the fame colliery of Howgill. 
Qq q 2 Partitioa 
