Page:Proceedings of the Royal Society of London Vol 1.djvu/177

Rh as a Certain proportion of sulphur communicates the same quality to iron, so are the effects of phOSphorus found to be; phosphoret of iron being, in this respect, much the most powerful, at least when con- sidered comparatively with sulphuret of iron.

8; and lastly. That as carbon, sulphur, and phosphorus, produce, by their union with iron, many chemical effects, of much similarity, so do each of them, when combined with that metal in certain pro- portions, not only permit it to receive, but also give it the peculiar power of retaining the magnetical properties; and thus henceforth, in addition to that carburet of iron called steel, certain sulphurets and phosphurets of iron may be regarded as bodies peculiarly suscep- tible of strong magnetical impregnation.

Among the observations which are subjoined to this paper, we ﬁnd some remarks on the vitriolization of pyrites; from which we collect, that, contrary to the opinion of Mr. Proust, who thought that only those pyrites in which the proportion of sulphur is very small are liable to this change, the vitriolization is not so much owing to the proportion as to the state of the sulphur in the compound; and that this state is probably the eﬁ'ect of a small portion of oxygen, previously combined with a pan: or with the general mass of the sulphur at the time of the original formation of the substances; so that the state of this ingredient is tending to that of oxide.

It is, no doubt, remarkable, that the magnetical properties of the sulphuret of iron, which forms the principal subject of this paper, should never have been adverted to by any of the writers on mag- netism. The few who observed it in the natural magnetical pyrites chose to ascribe it to particles of common magnetical iron interspersed in the ore : but from what has been stated, it is evident that this opinion must be relinquished; since there are certain known proportions of sulphur, as well as of carbon and phosphorus, beyond which the magnetical property will not be obtained, though the proportions beyond this maximum would by no means exclude the interposition of particles of iron. How far the combinations of magnetical sul- phurets, carburets, and phospholets may contribute towards the making artiﬁcial loadstones of greater strength than those hitherto known, is a subject recommended to the attention of future ob- servers.

The information we gather from this paper is, that the remarkable expansion of the skin of the neck, which constitutes a principal Character in this species, is a voluntary action, distinct from that inﬂation which all serpents, when irritated, are more or less capable of: that it is owing to a particular set of ribs situated at the neck of the