Analyfs 
1.The Venetian Method of preparing Cryftals 
of Tartar, commonly called CREAM OF 
TARTAR. Vol. I. p. 67. 
we following account was commu- 
nicated by M. Defmarets, as the 
relult of his perfonal cbfervation when at 
Venice. 
The neceflary utenfils in this manufac- 
ture are the following : 
1. An iven boiler. 
2. From 25 to 30 wooden tubs, about 
three feet hich, and four feet acrofs. 
3. Twelve copper boilers, three feet and 
‘a half deep, one foot and a half in diame- 
ter at the bottom, and about three feet and 
a half acrofs at the top. 
4. Alarge ladle, pierced with holes, for 
the parpofe of taking off the fcum, 
5. A large iron mortar and peftle. 
6. An earthenware bafon to beat up 
whites. of eggs in, and a few wooden 
bowls. 
The number of perfons required to car.y 
on an eitablifhment of this fize, is one {u- 
perintendent, and two affiftants. 
PROCESS. : 
1. The crude tartar is dried by a very 
gentle heat in the iron boiler, care being 
taken to ftir it frequently, fo that it may 
not burn at the bottom :-when thoroughly 
dry, it is to be pounded in the iron mor- 
tar. 
2. The tartar thus pulverifed is to be 
diftributed into eight of the wooden tubs, 
which are then filied with a quantity of 
hot water fufficient to diflolve the tartar: 
after ftanding awhile, a fediment is depo- 
fited, from which the liquor is poured off 
clear into another tub. e 
The folution thus freed from fome 
of its impurities, is left three days at reft; 
during which time it depofits brownith 
cryfals of tartar: the mother liquor ts 
preferved for procefs 2 with a freth parcel 
of crude tartar. _ 
4. Three of the copper boilers being 
filled with ireth water, a /ufficient quantity 
of prepared tartar is added, and a very 
geotle heat is applied by occafonally burn. 
ing a faggot of brufh-wood, fo as that the 
complete folution of the tartar is not ef 
tected in lefs than eight houis; at the end 
of this time the I:quor is changed from a 
dirty red to a deep yellow wine colour, 
anti is made to bei. While the fuperin- 
tcndent is thus ergaged, his two. afliftants 
are employed in the previous operations. 
5. When the ebuilitionybas gene on a 
hait an hour, the liquor is clarified : 
this purpofe the matier workmap {tations 
him:eti by the fide of one af the coppers, 
064 
of the Fournal de Phyf gue. 
[Jan. ] 
with a bafket of eggs, a bucket full of 
wood-afhes finely fifted, the perforated 
ladle, the earthen bowl, and an empty 
bucket. He begins with breaking one of 
the eggs, and putting the white of it into 
the bow], taking particular care not to mix 
it with the yolk: this he beats up with 
fome of the boiling liquor, and, when its 
parts are well mingled, pours it on the 
furface of the boiler: he then sutenaly 
takes a {mall quantity of wood-af on the 
end of the ladle, and flirs up the liquor 
with it fromthe bottom. A brifkeffervef- 
cencetakes place, and the furface is covered 
with a red fcum; this is carefully taken 
off with the ladle, and put into the empty 
bucket: a fecond portioh of wood-ath is 
then added, and effervefcence and a red 
{cum are produced as before. ‘The whole 
of this operation with the white of egg 
and wood-afh is repeated fourteen or fif- 
teen times, after which the liquor becomes 
colourlefs. 
6. The fire is now withdrawn, and the 
liquor fuffered to remain perfectly at reft 
for three days. On the fourth, a faline 
cruft of a dirty white is removed from the 
furface, and two-thirds of the liquor ladled 
out: the cryftals on the fides are then col- 
leéted by the ladle, and wafhed in the re- 
maining liquor; they are thus obtained 
perfectly clean, and require no further pre- 
paration than drying on a wicker frame. 
The cryftals trom the bottom are ftill a 
little coloured, and are either collected for 
an inferior fort, or fubjected to procefs 
2, &c. The liquor in which the cryftals 
were formed, as well as the faline cruft, 
are both referred to procefs 2, &c. 
REMARKS. 
The fcarlet dyers object to the ufe of 
Venetian cream ef tartar, on account of its 
requiting a greater quantity of nitro-muriat 
of tin, than the German tartar. 
is confiderably more acid to the tafte; and the 
moxe predominant the acid is, the better is 
the article fitted for the ufe of the dyers. At 
Montpellier the tartar is purified without 
wood-afhes, the earth of Blurvel being fub- 
ftituted in their ftead ; and it would be an ob- 
vious improvement of the Venetian method 
to begin the 6th procefs by adding as much 
fulphuric acid as would faturate the alkali 
ot the aihes emeaee in the preceding ope- 
ration. 
Il. « new Method of making Ponds, Sc. 
Water-tight, without the ufe of Mafonry ; 
by M. D'Ambournai, Vol. I. p. 237. 
The, pond may be dug to any depth, 
taking care to flope its fides to an angle of 
abour 40 degrees. ‘ 
The cement with Which it is to be lined, 
muit 
This latter | 
