|| freed from this, it does not destroy the colour of 
| dry litmus paper. 
_ matter: the chlorine attracts the hydrogen of 
| by changing its constitution, alters its relation 
_ applied this agency of chlorine to the process of 
thread or cloth to the action of the gas itself; 
_ water, being more economical, was afterwards 
: CHLORINE. 
solved in water, it is immediately transformed 
into a salt; the sodium attracts oxygen and be- 
comes soda, and the chlorine takes hydrogen and 
becomes muriatic acid, and muriate of soda ex- 
ists in the solution. When any of the compounds 
of chlorine, with inflammable substances or me- 
tals, are subjected to the action of a galvanic 
apparatus sufficiently powerful to decompose 
them, the chlorine is always evolved at the posi- 
tive pole of the battery, and the base at the ne- 
gative pole. In this respect, and in its power of 
supporting combustion, chlorine is analogous to 
oxygen. 
One of the most important chemical proper- 
ties of chlorine is displayed in its action on the 
vegetable colours. Many of them it entirely 
| destroys; and even those which are the most 
deep and permanent, such as the colour of indigo, 
it renders faint, and changes to a light yellow or 
brown. This agency is exerted by it, both in its 
gaseous and its liquid form. The presence of 
water is, however, necessary to this. Hence, 
when the gas destroys colour, it must, probably, 
be enabled so to do by the hygrometric water it 
contains. It is accordingly found, that, when 
The destruction of colour 
appears to be owing to the communication of the 
oxygen of the water present to the colouring 
the water to form muriatic acid, and the evolved 
oxygen unites with the colouring matter, and, 
to light, so that the tint disappears. Berthollet 
bleaching, and with such success as to have 
entirely changed the manipulations of that art. 
The method of using it has been successively im- 
proved. It consisted, at first, in subjecting the 
but the effect, in this way, was unequally pro- 
duced, and the strength and texture were some- 
times injured. It was then applied, condensed 
by water, and in acertain state of dilution. The 
thread, or cloth, was prepared as in the old me- 
thod of bleaching, by boiling first in water, and 
then in alkaline lye; it was then immersed in 
the diluted chlorine: this alternate application 
of alkali and chlorine was continued until the 
colour was discharged. The offensive, suffocat- 
ing odour of the gas rendered this mode of using 
it, however, scarcely practicable: the odour was 
found to be removed by condensing the chlorine 
by a weak solution of potash: lime, diffused in 
substituted. Under all these forms, the chlorine, 
by decomposing water, and causing oxygen to be 
imparted to the colouring matter, weakens or 
discharges the colour, and the colouring matter 
appears to be rendered more soluble in the al- 
kaline solution, alternately applied, and of course 
more easily extracted by its action. More lately, 
a compound of chlorine and lime has been em- 
in water, forms the bleaching liquor now com- 
is then repeatedly washed with a solution of 
ployed, prepared by exposing slacked lime to || 
chlorine gas: the gas is quickly absorbed, and || 
the chloride of lime, as it is called, being dissolved 
monly employed, and which possesses many ad- 
vantages. In using it, the coloured cloth is 
first steeped in warm water to clean it, and 
caustic potash, so diluted that it cannot injure 
the texture of the cloth, and which is thrown 
upon it by a pump; the cloth is then washed | 
and steeped in a very weak solution of chlo- 
ride of lime, again washed, acted on by a boil- 
ing lye as before, and again steeped in the 
solution; and these operations are performed 
alternately several times. The cloth is lastly 
immersed in very dilute sulphuric acid, which 
gives it a pure white colour; after which it is 
washed and dried. Chloride of magnesia has 
been substituted, with great advantage, for that 
of lime, in whitening cloth for calico printing; 
the cloth, when lime is used, retaining a little of || 
it, which, in the subsequent operation of clearing 
by immersion in weak sulphuric acid, forms sul- || 
phate of lime, which remains, and affects the 
colours when it is dyed; while the sulphate of 
magnesia is so soluble, that it is entirely removed. 
Chloride of alumine has been employed to dis- 
charge the colour of the Turkey-red dye, which 
resists the action of other chlorides, and is only 
discharged by chlorine gas, by an operation very 
injurious to the workmen. 
Another important application of chlorine gas 
is that of destroying or neutralizing contagion. 
Acid vapours, sulphurous acid in particular, under 
the form of the fumes of burning sulphur, had 
often been employed for that purpose; but chlo- 
rine, from the facility with which it decomposes 
the different compound gases that contain the || 
elements of vegetable and animal matter, and || 
which may be supposed to constitute noxious ef- 
fluvia, is superior to any other agent, and is now 
universally employed for the purposes of fumiga- 
tion. It is the only agent which can administer 
relief in cases of asphyxia from sulphureted hy- 
drogen ; and it has been found useful, among such 
persons as are obliged to frequent places where 
contagious effluvia are constantly developed, to || 
bathe the hands and arms with its solution. 
The chloride of lime has, for some years past, 
been very generally and most successfully intro- 
duced to the stable, the cow-house, and the farm- 
yard, both as a disinfectant and as a’specific for 
putrid diseases, Youatt, in each of his great || 
works, speaks very highly of its value to the far- || 
rier and the farmer; and Clater, in his ‘ Cattle 
Doctor,’ says respecting it, “In the malignant 
diseases of cattle, it is exceedingly useful as a lo- 
tion, and almost equally so given internally when | 
the disease is beginning to assume a putrid char- || 
acter; but its great value consists in its freeing 
the stable and the cow-house and the harness 
from infection of every kind. If they are thor- 
ase 
