46. | : Lleaching—Dying, &e. 
they are now to be a fecond time placed 
In a cauldron of water, of the fame heat 
as the former, which is to be renewed fo 
Jong as it contains any animally jelly ; af- 
ter this procefs, they are to be placed on 
the horfe, and the cellular membrane 
and pannicelus carnofus are to be taken 
off. The cauldron is now to be filled 
with filtered tan-liquor, of the before- 
mentioned temperature, into which the 
fkins are to be placed till completely tan- 
‘ned, the liquor being renewed from time 
to time. ~The leather is now to be cur- 
ried in the ufual manner, then foaked in 
melted fat, and, laftly, compreffed be- 
tween iron rollers.—Vol. I. p. 202. 
We are prefented, in the fecond vo- 
lume, with an improved method of tan- 
ning, invented by Dr. Macbride, of 
Dublmn. It confifts in the ufe of lime- 
water, inftead of common: water, in pre- 
paring the infufion of tan; and in fub- 
ftiruting diluted vitriolic acid in place of 
the ufval fourings—vVol. If. p. 341. 
In January, 1790, a patent was granted 
to Mr. Hooper, of London, for manu- 
facturing from leather-cuttings, a leather 
for covering coaches, &c. for binding 
books ; and for making from leather- 
cuttings, mixed with ! rags or hemp, 
various forts of paper, from the confmon 
brown, to that which is ufed in copper- 
plate printing, the procefs is the fame 
with that of the paper manufaétory. 
—Vol. If. p. 371. 
The fame volume contains a paper by the 
Rev. Geo. Swayne, of Pucclechurch, near 
Briftol, on the ,ufe of oak-leaves in tan- 
ning; from which it appears, that half 
a peck of leaves, contains nearly as much 
aftringent matter, as one pound of bark. 
The’ price of bark, in Mr. Swayne’s 
neighbourhocd, when properly dried and 
cleaned, was fix pounds per ton; he has 
had oak leaves colle€ted at four-pence the 
fack of four bufhels ; one fack of leaves 
contains as much aftringent matter, as 
thirty-two pounds of bark; of the for- 
mer, the price was qd. of the. latter 
1s. 83.—Vol IT. p. 406. 
In May, 1795, a patent was granted to 
John Tucker, of Wickham, tanner, for 
an improvement in his art, whereby the 
time requifite for tanning leather was 
fhortened, and its quality improved. 
This new -method ‘confifts in adapting 
flues to the ooxe-vat, fo as to heat the 
water, and thereby increafe the aétion of 
the tan.—Vol. II]. p. 217. 
II. BtracHiING AND DyINé. 
Under this head there is a very valua- 
ble account, extra€ted from the Annales 
a [ Feb. 
de Chimie, of the new method of bleach- 
ing, by means of the oxygenated muria- 
tic acid, by Mr. Berthollet. Having 
prepared a quantity of this acid, fufi- 
ciently diluted with water, the cloth is 
firft to be fubmitted to the a€tion of one 
or two good leys, and then immerfed for 
three hours in the acid ; the liquor being 
then wrung out of the cloth, it is again 
to be plunged into the ley, thus alier- 
nately making ule of the acid and ley, 
till the cloth appears white, after which 
it is to be impregnated with black foap, 
ftrongly rubbed, and then fubmitted to 
the laft ley and the laft immerfion. The 
number of leys and immertfions, for linen 
or hempen cloths, varies from four to 
eight ; but for cotton, a much’ weaker 
acid, and a fewer number of times, are 
fofficient. To afcertain the ftrength of 
the acid,’ one meafure of a folution of 
cochineal, is put into a graduated glats 
tube, and the acid by degrees added to 
itr, till the colour of the cochineal is de- 
ftroyed : and having previoufly determi- 
ned how many meafures of acid, the 
proper ftrength of which has been af- 
certained by experiments on cloth, are 
neceflary to deftroy the colour of one 
meafure of cochineal; this known pro- 
portion will ferve as a et to 
eftimate the refpeCtive ftrength of all the 
bleaching mixtures, with which it may 
be neceflary to compare it-— Vol. I. 
a3. 
Mr. He&tor Campbell has obtained a 
patent for biaching linen rags and’ other 
materials, ufed in making paper, by 
means of Berthollet’s procefs, as men- 
tioned above.—Vol. I. p. 156. — ' 
A paper of Mr. Chaptal’s, tranflated 
from the Memoirs of the Academy of 
Sciences of Paris, befides mentioning the 
‘procefs of bleaching rags, by means of 
the oxygenated muriatic acid, contains a 
inethod of recovering old ftained books: 
‘and fmoaked prints, by the ufe of the 
fame acid.— Vol. I. p. 355. aa 
This work is enriched by a tranfcript 
from the Manchefter Philofophical Me- 
moirs of Mr. Henry’s (of Manchefter) 
valuable paper, on the nature of wool, 
filk, and cotton, as objeéts of dying 3 
together with a detailed account of the 
elaborate procefs of dying Turkey red. 
—Vol. II. p. 41. 
Ill. ExFRACTING 
PIT-CoAL. 
Lord Dundonald obtained a patent for 
this procefs, the peculiarity of which 
confifts in the ufe of open veffels, inftead 
of clofe ones, as was formerly made 
OF 5 
TaR ‘FROM 
