Faraday's discovery of butylene, isomeric with ethylene, in 1825.
Butylene,* C 4 H 81 exists in three isomeric forms: normal butylene,1C 2 H 5 CH:CH 2; pseudo-butylene, CH 3.
Normal butylene is a readily condensible gas.
the vapour densities of the isomers were the same, as in butylene and isobutylene, to take the most simple case; here the molecular conception admits that the isolated groups in which the atoms are united, i.e.
the molecules, are identical, and so the molecule of both butylene and isobutylene is indicated by the same chemical symbol C4118, expressing that each molecule contains, in both cases, four atoms of carbon (C) and eight of hydrogen (H).