American watchman and Delaware advertiser. [volume] (Wilmington, Del.) 1822-1828, 1822-06-25

colorng of Scarlet 1t will be found valuable arti
Gle, both to the man of science and to the practca
manufacturer. 1t affords US pleasure to state tina
our correspondent is preparing practical trea
tse on the dying Of woollens which will be pub
ishcd between this and the next autumn. There
is work Of the kind in this country and such q
publication at time when woollen manufactures
are springng up in all directions is great beside
ratum. The talents and experience Of Hopson JUS
,fy the sangune antcipations of the ability &
usefulness of his contempt ated treatise.N Y. STAT
For the Statesman.
MEssRs. EDrroRs.--In two papers signed Hop
son, criticised several parts at the theory of dy-
ing, as advanced by doctor Cooper, in his work on
that subject shall take the liberty of recying one
other error, through the medium Of your paper
which must have had tendency to bewilder the
mere practical artist.
"P. "a. Aquafortis or strong nitric acid coIorIess
This will be wanted to make the scarlet compost
ton. 1t ought to be freed from sulphuric acid by
nitrate Of barytes and from muriatc acid by nitrate
of silver
This hypothesis is directly opposed to the prac-
tlce OF the most eminent dyers, will it hold good
in theory. Muriatc acid must always be present to
enable the nitric to hold the tin in solution and il
is customary to mix one eighth of muriatic acid
with the nitric, before any lin is added. Sulphuric
acid is considered at all urious provided
it be free from iron.
There are but two FIRST rate public scarlet dyers
in the west of England both Of them use single
aquafortis slightly tinged with orange colored fumes
lone OF those dyers adds fine salt to his compost
ton for scarlet and the other the above mentioned
portion Of muratic acid.
shall take this opportunity of disclosing fact
relative to the scarlet composition, which tscov-
cred in the year 1907, and which has never before
been made known. was then engaged in making
experiments IN London at the laboratory of Mr.
William Bryan, sen'r," for the purpose of ascertain
ing the precise effect produced by the mordants on
the materia tnctoria. My experiments were moi
confined to the effect which a single mordan ha,
on given coloring matter; it was extended to ter.
nary and even quarternary compounds.
Whilst so employed, put into phiaI of aqua
regla, as much pulverised tartar as l had been ac
customed to use in the dying furnace, with the sam
portion of acid. The bottle labelled and laid by
on shelf. About two months afterwards was en-
gagged in experimenting on the coloring matters
producing yellow, when used some Of the afore
said liquor with detection Of the morus tinctora,
old fustic). The effect produced was astonishing
the color being far more brilliant than any | have
ever seen produced from the same material; and it
has proved, after the most severe trials, to be as
permanent as it was beautiful On examining the
list Of patterns in April 1921, found all the other
yellows we're faded, whilst that one retained its or
ginal body and lustre.
Doctor Bancroft had previously established the
fact, that scarlet was produced by portion of the
cochnea being yelowed and | inferred at the
time made the experiment, that the tartaric acid
OF the supcrtartrate of potash, was the only mate
rial by which that effect was produced. soon after
communicated this idea to Doctor b. and in his Sc.
cond volume published ubsequent to my informa-
ton, he has given it his opinion, observing that
tararic acid was too dear to be used for that purpose
IN the year 1910 made some experiments on
cochlneai with the same mixture, and the color pro-
duced answered my most sanguine expectation
This color was very brilliant and well grounded and
on trial found it would stand washing and expos
ure to atmospheric changes, much better than any
scarlet dyed alter the common mode.
have long wished for an opportunity Of enter
ing on course OF experiment, ascertain the be St
proportion of materials in preparing this nitro murio
tartrate OF potash, and the exact quantity be used
TO produce the best color, with any given quantity
of cochineal. have no doubt the result would be
highly valuable to the dyer of scarlet, as the ex
peDse Of producing the color would be much less :
ened, and the acids consumed much smaller inl
quantity.
The proportion of aqua regs, nearly saturated
with TIM used in the old mode of dying scarlet is 81
pounds to Of cochineal. The materials are added
when the liquor is boiling the acids FIRST, and the
others in succession as the cream of tartar is
F~N'P'"N~1 '',0 NHS iAHoo'' Q Su'u Hhb appearance
Immediately takes place, which will soon precpi-
tate, it permitted to rest. When the cloth is wash
ed after dying the filth extracted is of white color
and when the spent LIQUOR is thrown away. large
quantity Of white precipitae is always found in the
bottom of the furnace, considerable portion of
which is evidently metallic.
The following appears to be the true rationale Of
scarlet dying at least such the differences have
drawn from the experiments before related, and
from the effects of the old process
The Of tartar is decomposed by the nitro
muriatc acid. The potash of the tarra,e of NOT
ash, combines with portion of the aqua repia of
The miro nt tin lie tin is ~