ETHYLENE, a gaseous hydrocarbon hav ing the formula GIL, and constituting the first member of the olefine series. It is formed in the dry distillation of numerous organic bodies, and constitutes 4 to 5 per cent of ordinary coal gas. It is most conveniently prepared for labor atory purposes by mixing 1 part of alcohol with 4 parts of sulphuric acid, adding enough sand to form a paste, and heating the mass over a flame. The sand takes no part in the chemis try of the process, but merely serves to regu late the action. The sulphuric acid, owing to its affinity for water, removes the elements of water from the alcohol, and thereby liberates the ethylene, GIL.OH—H20±C.2114. Ethylene is a colorless gas, which burns with a bright flame, a five-foot burner, using the pure gas, yielding a light of 68 candle-power. It may be condensed to a transparent liquid which boils, under ordinary atmospheric pressure, at 153° F. below zero, and freezes at 272° F. be
low zero. Ethylene is an unsaturated compound, and combines directly with hydrogen when mixed with that gas and led over platinum black; the product of the combination being ethane, C,H.. Mixed with three times its own volume of oxygen, and fired by a spark, ethylene explodes with great violence. When it is mixed with chlorine in the dark, combination takes place according to the formula FLCI., the new substance being an oily fluid, known as ethylene dichloride, or °Dutch liquid.) It is on account of this reaction that ethylene was formerly called "olefiant) (or °oil-form ing") gas. It will be observed that the fore going reaction is an additive one. In diffuse daylight chlorine attacks the dichloride of ethy lene, with the formation of more highly chlorinated substitution products, of which the highest is Ciao.