^{page 514 note *} Wurtz, in a note to a paper by v. Oefele on “Diethyl Sulphan” in the Bulletin de la Société Chimique de Paris for February 1865, formulates that among other sulphur compounds on the assumption of diatomic sulphur. But it must be remembered that this body (C₂H₅)₂SO_2, contains in the molecule only two monad radicals, so that it takes its place beside chloride of sulphuryl rather than in the series, since discovered by v. Oefele, of which the starting point is the iodide of triethyl sulphin S(C₂H₅)₃I.

^{page 515 note *} I use here, for the purpose of representing the chemical structure of molecules, the graphic method which I first introduced in my thesis presented to the Medical Faculty of the University in 1861, and which I have more than once employed in papers read before this Society. I am happy to observe that its advantages are appreciated by others, Dr Hofmann, for instance, using a system almost identical in his lecture delivered before the Royal Institution on the 7th of April of this year.