Se aE aces CS ESSE a eee ee Pee ees eS Te eee ey ae ee 
| 
‘ 
j 
: 
be 
GYPSUM. 
into a on iaie, which, however, is faid foon to fall into 
a white 
ant ig ciao crucible, according to Klaproth’s expe- 
pfum had turned white and very fri- 
pea gies wich the gue of Gp ger per cent. of its weight ; but in the 
clay crucible it had melted into a clove-brown "glafs, with 
a pherical veficles 
ulphate of lime is “foluble in water ; ; but it requires not 
lefs than a hundred times its weight of water, and ‘a mean 
temperature. It does not effervefce with acids, nor is it de- 
send by any of aie 3 it may be diflolved by the we 
a 
“ 
> 
5 
R 
og | 
= 
&. 
5 3 
a 
mee 
a) 
a” 
? 
o 
a 
Qu 
oO 
= 
_ 
e 
bad 
Lome | 
4 
erithe a by a dave ati when boiled i in a folution 
the alkaline carbor 
The ufeé'made of re ales fub-fpecies of gypfam_for 
economical purpofes is of confiderable importance. They 
pellets t the quality of improving, by a chemical combination 
not perfectly se rae, the quality of the foil, efpeciall 
when too {tiff and c mys and are, therefore, frequently 
employed for the iis of land, both in Europe and 
Gypfum, when deprived of its water of cryftallization by 
heat, is called plafter.. Of this the coarfer forts are employed, 
the admixture of common lime-ftone, for cements. 
The sypfum, which naturally contains carbonate of lime, 
ood cement ; but that which has an admixture 
eat fince j in this ore the aie will be A ip me of its 
; gesbori afelid mafs when mixed with a certain 
Portion of w: During the procefs of pavion, the 
water of eryfallization rifes as a white vapour, W ich, if 
7, is quickl diffolved in air. 
On the river Wolga, in Raita, - the pte: Of gypfum 
: ey 
a 
pafs — a fieve, and form it into {mall round cakes, 
whchthey ll at from Ito 14 ta wig on ufand. 
the » water is added to the 
ne of 
e {parry 
ureft of all, is eicesd fie ee 
(fee IMpREssions) 5 an 
ef marble, granite, and: | 
1 by the name of Scagliala, derived from 
i, or lamine of felenite, which latter is 
sox b and Pegnee, and alfo in Eng- 
Fleas fain s 
Set lefs the'gy ofan 9 for platter i is mixed with 
and very flat, soles in the marle, and even amorphous 
maffes or irre umps of great thicknefs and extente 
Thefe appearances (oom to arife from the gypfum not form- 
ing regular or continuous ftrata in the marl, kta is its 
matrix, but accidental beds, or nodules, fizes and 
fhapes, as is obferved of the ieyillivente teh nodules’ 
in their ufual matrixes of fhale, bind, or clay (except that 
thefe laft are never very large), and of other nodular im- 
bedded fubftanc 
The n cndellin: or accidental beds, of the vaft ft 
of red marle which occur in England beneath the lias ftrata, 
ve rae Aeptsmat, are, as 
gypfum, limeitone, Png oi fienite, “flat bafalt, fand, 
micaceous fine grit- ry coarfe grit or pudding tone, 
brick-clay, &c. and oethad local fields. of 
carboniferous ftrata or coal-meafures, which are. rms alter. 
nating with, or furrounded by red marle (containing often 
light blue freaks or patches), cover the greater part of the 
furface of England and Wales, north and weft of the regular 
ffet of the lias clay and limeftones; and it feems 
probable that it has been owing to the local {tripping off or 
ns of t marle, nearly all of the im- 
portant ftrata containing and ar, iron-ftone 
have been laid bare or expofed, rs aaa se in thefe 
— ‘ 
It feems probable that there are feveral other ftrata of 
gypfeous marle, befides the Britifh Saivooeclionate ka 
different parts of the world. Thofe of the — of Paris 
are certainly upper ftrata to the chalk of uth-eaft of 
England (ee Phil Mag. vol. xxxv. p. 131.) Lan greatly 
It feems, however, that 
It rocks and {prings, are common in all faut 
_the other anomalous ae mentioned above 
‘above the Englith red marle ftrata. 
f where gypfum is a? int, 
England, Raat &c. may ses ——s to many of 
our readers, vi 
Chelles, 
rns oe of Paris in France. 
geen N. of Baste, Seton 
Mating 
