182L] of Chlorine and Carbon, &;c. 115 



lamp, and, on passing into the hot part of the tube, is decom- 

 posed ; a fluid passes over, which is condensed in the angles of 

 the tube, and chlorine is evolved ; part of the gas escapes, but 

 the greater portion is retained in solution by the fluid, and renders 

 it yellow. Having proceeded thus far, by the careful application 

 of a lamp and blow-pipe, the bent part of the tube may be sepa- 

 rated from that within the furnace, and the end closed, so as to 

 form a small retort ; and on distilling the fluid four or five times 

 from one angle to the other, all the chlorine may be driven off 

 without any loss of the substance, and it becomes limpid and 

 colourless. It still, however, always contains some perchloride, 

 which has escaped decomposition; and, to separate this, I have 

 boiled the fluid until the tube was nearly full of its vapour, and 

 then closing the end that still remained open, by a lamp and 

 blowpipe, have afterwards left the whole to cool. It is then easy, 

 by collecting all the fluid into one end of the tube, and introduc- 

 ing that end through a cork into a receiver, under which a very 

 small flame is burning, to distil the whole of the fluid at a tem- 

 perature very little above that of the atmosphere. The solid 

 chloride being less volatile does not rise so soon, and the pure 

 protochloride collects at the external end of the tube. To ascer- 

 tain its purity, a drop may be placed on a glass plate ; it will 

 immediately evaporate, and if it contains perchloride, that sub- 

 stance will be left behind ; otherwise, no trace will remain on 

 the glass. The presence or absence of free chlorine may be 

 ascertained by dissolving a little of the fluid in alcohol or ether, 

 and testing by nitrate of silver. 



The pure protochloride of carbon is a highly limpid fluid, and 

 perfectly colourless. Its specific gravity is 1-5526. It is a 

 non-conductor of electricity. I am indebted to Dr. Wollaston 

 for the determination of the refractive power of this chloride, 

 and for the approximation to the refractive power given of the 

 perchloride. In the present case it is T4875, being very nearly 

 that of camphor. It is not combustible except when held in a 

 flame, as of a spirit lamp, and then it burns with a bright yellow 

 light, much smoke, and fumes of muriatic acid. 



It does not become solid at the zero of Fahrenheit's scale. 

 When its temperature is raised under the surface of water to 

 between 160° and 170°, it is converted into vapour, and remains 

 in that state until the temperature is lowered. When heated 

 more highly, as by being passed over red hot rock crystal in a 

 glass tubs, a small portion is always decomposed; nearly all 

 the fluid may, however, be condensed again, but it passes slightly 

 coloured, and the tube and crystal are blackened on the surface 

 by charcoal. I am uncertain whether this decomposition ought 

 not to be attributed rather to the action of the glass at this high 

 temperature than to the heat alone. 



It is not soluble in water, but remains at the bottom of it in 

 drops, for many weeks, without any action. 



i2 



