'June 10,1871.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
991 
while the production of printed goods is yearly increas- 
ing, the number of operatives employed is nearly sta¬ 
tionary ; the number of print-works is also smaller than 
previously, the small works having been gradually sup¬ 
planted by a few large ones. Some of these are very ex¬ 
tensive, employing over 1000 operatives, and producing 
’nearly 1,500,000 pieces of printed cloth per annum. 
Of the very many colouring matters known, compara¬ 
tively few are now employed by the calico printer in 
producing all the combinations of colours he requires ; 
and these vary greatly, both in the manner of applica-. 
tion and in the value of the effects produced; and as 
■ chemistry has furnished us with a host of new colouring 
matters,—aniline, phenol, naphthaline, and anthracine 
•colours,—and as these are commercially valuable just in 
• so far as they can be employed by the dyer and printer, 
I have thought that a brief sketch of the various opera¬ 
tions, and the chemical changes involved, might possess 
. some little interest. 
Fibres may be generally divided into two classes, 
■ animal fibre and vegetable fibre,—the former re¬ 
presented by silk and wool, the latter by flax and 
< cotton, which entirely differ, both in their formation 
' and in the manner in which they retain colouring mat¬ 
ters. Animal fibre, such as wool, presents under the 
microscope the appearance of a solid cylinder of a soft 
. spongy matter, has considerable elasticity, and absorbs 
and retains readily most colouring matters. It contains a 
.fatty matter, from which it has to be freed by scouring 
with very weak alkali, to prepare it for dyeing. Wool, 
.also, is strongly acted on, indeed dissolved by alkalies, and 
it is turned yellow by immersion in nitric or sulphuric 
.acids. Cotton, on the other hand, is unchanged in colour 
by N Oj or S 0 3 , but first swells up, and by lengthened 
immersion dissolves in these acids, while it is nearly un- 
affected by treatment with alkaline solutions, and it con¬ 
tains no oil in the fibre. Wool not only absorbs colour- 
■ ing matters from their solutions, but many metallic 
salts (as AL0 3 S0 3 ), which cannot be removed by wash¬ 
ing with cold water, and only by large volumes of boil¬ 
ing water. Cotton, on the other hand, has a very weak 
.affinity for metallic salts and colour. When viewed 
nnder the microscope, a cct’:on fibre presents the appear¬ 
ance of a hollow cylindrical tube, sometimes slightly 
-■oval, the walls of the tube being coated with a fine 
.-down. Some chemists, as Persoz, have maintained that 
■the union of fibres with metallic salts and colouring mat¬ 
ters was purely chemical, and that the difference between 
wool and cotton in this respect was simply one of degree. 
-However, Mr. Crum has shown that dyed cotton cloth 
.retains the colour simply mechanically ; in other words, 
the dyeing of cotton consists in introducing the colouring 
••matter in a soluble form into the hollow tube, and then 
-solidifying it by forming an insoluble lake with some 
metallic salt or other mordant, when the insoluble com¬ 
pound so produced is unable to escape by the narrow 
openings of the fibre. 
In unripe or not fully-developed cotton the tube is 
nearly flat, and too narrow to admit of solution ; conse¬ 
quently, this cotton will not dye. The printer receives 
•the grey cloth direct from the loom, and turns it out 
-ready to be made up into dresses, which involves 
.several operations preparatory to, and succeeding, the 
impression of the coloured pattern on the cloth. Pre¬ 
paratory to the printing, the cloth is singed and 
■bleached. 
Singeing is a purely mechanical operation, and has for 
its object the removal of the soft down coating the ex¬ 
terior of the fibres. The appliance consists of a small fur¬ 
nace about 10 ft. long by 6 ft. high and 5 ft. broad; in the 
-middle of the roof of the furnace, and running its entire 
length, is a semicircular bar of copper, which is kept red- 
hot by the fire underneath. The cloth is drawn over, 
.and, by pressing in its passage the red-hot copper bar, 
the down on the cloth is burnt off; but the spark on 
idle cloth is extinguished before the cloth can be materially 
injured bypassing immediately through a trough of cold 
water. This operation, if properly conducted, does not 
injure the strength of the fibre, which should sustain the 
same strain after as before singeing. The next opera¬ 
tion is bleaching. 
Bleaching has for its object purification of the fabric 
from all coloured or other impurities, whether naturally 
associated with the tissues or added to serve some pur¬ 
pose, and wdiich, communicating more or less colour to 
the cloth, thereby destroy its beauty. These are a re¬ 
sinous matter, a yellowish colour, soluble in alkalies; 
the dressing employed in the manufacture of the cloth, 
and the coloration produced by singeing. This process 
is conducted in the following manner:— 
_ The grey cloth is first damped (by passing through a 
cistern filled with cold water, and is then drawn through 
squeezers, by which the damping is made uniform and 
the excess of water removed) to make it less bulky in 
the kier, to which it is transferred from the squeezers by 
a winch. 
During the filling of the kier the valves at the bottom 
are kept open to allow of the escape of any moisture 
which may fall to the bottom. 
In a pot or small boiler, 60 lb. of burnt lime shell are 
slaked and boiled with 100 lb. of soda ash dissolved in 
water, until the carbonate of soda is converted into 
caustic soda. 
The solution is allowed to clarify by resting till the 
sediment (CaOCCh) has fallen to the bottom, and the 
clear solution is drawn off by a valve situated a few 
inches above the bottom of the pot, and run into the 
kier where the grey cloth has been arranged. The 
charge is made up wdth water to 900 gallons, or till the 
cloth is covered with the alkaline solution. This is the 
charge for 4000 lb. of grey muslins or calicoes, and is 
boiled for four hours under 35 lb. pressure steam. 
The solution is then drawn off from the kier into a 
cistern, where it is kept for further use, and the goods 
are cooled by running cold water on them, which is al¬ 
lowed to drain off by the bottom of the kier. 
The cloth is then run from the kier through a machine, 
fed with 200 lb. burnt lime shell slaked and made into 
a cream with water, and back to the kier, where it is 
boiled (with the liquor of the first boil and the 200 lb. of 
' ime which it took up in passing through the machine) 
for ten hours with open kiers. 
The exhausted liquor is of no further use and is thrown 
away; the goods are then cooled, passed through a 
washing machine with cold water, and then through a 
souring machine, fed with sulphuric acid, at 4° Tw., and 
allowed to lie in the sour taken up, on a drainer for four 
'lours. 
The cloth is then washed by passing through a ma¬ 
chine with water, twice if the water be not very pure, 
but if quite pure, the washing may be effected by pour¬ 
ing water upon the goods till the sour is washed out. 
The goods are then run back to the kier and boiled 
with a charge consisting of 250 lb. of soda ash, 60 lb. of 
rosin and 900 gallons of water (which has been previously 
prepared in the following manner), for ten hours, under 
35 lb. pressure of steam. The 250 lb. soda ash are dis¬ 
solved in 150 gallons of water and added to the 60 lb. 
rosin. This solution of rosin soap is then run into the 
kier and water added up to 900 gallons, with the 4000 
lb. of cloth, and boiled, as before stated, for ten hours 
under 35 lb. pressure of steam. 
The liquor is then run off and the goods cooled as 
before. The goods are then washed in a machine and 
passed through squeezers. The cloth is then passed 
through a machine, fed with bleaching liquor, at 1° to 2° 
on the chlorine test, and allowed to lie on a drainer four 
hours. It is then sweetened by passing through a ma¬ 
chine with water, soured as before, and the sour washed 
out by twice washing with cold water. 
It is then dried on steam-heated cylinders. 
Previous to printing, the cloth is shaved, or freed from- 
