Page:Proceedings of the Royal Society of London Vol 1.djvu/380

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to be present. The quantity of sulphate of barytes produced from 100 of sulphate of lime was accordingly ascertained, and found to be 175'9; and 100 grains of crystallized sulphate of mag- nesia were found to give 112 of sulphate of barytes. And since the aggregate quantity of sulphuric acid obtained from any quantity of salt examined was found to agree with the above proportions, it was inferred that no alkaline sulphate was present in any of the varieties of mxiriate of soda, whether of English or foreign manufacture.

In addition to the author’ 8 account of the methods pursued in his analyses, he also mentions various objects of inquiry respecting the preparation of salt, which may be interesting to chemical readers :— such as the specific gravity of the original brine of Cheshire, and its original contents; the specific gravity of mother liquors, and their ultimate contents; the clearings of brine, which are raked out as soon as the salt begins to granulate; the pan-scale, that forms as a hard crust, attached to the pen in which the brine is evaporated; and the varieties in this scale, under different circumstances.

The difference between sea-water and the brine from salt-springs is also stated, and the extreme difference also of the residua obtained from the respective mother liquors, especially in respect to muriate of magnesia; since the mother liquors of Cheshire contain only 35 parts in 1000, while that of the other amounts to 874; the mere refuse of the Cheshire processes being nearly equal in purity to some kinds of salt prepared from sea-water.

Description of an extraordinary Human Fwtus. In a Letter from Mr. Benjamin Gibson, Surgeon, to H. Leigh Thomas, Esq.F.R.S. Read February 8, 1810. [Phil. Trans. 1810, p. 123.]

Although instances of human bodies nearly entire, united side by side, or back to back. or otherwiso, are by no means rare in the collections of anatomists ; and although such a conjunction is generally not connected with any peculiarity in the organs which compose them, and lead the physiologist to anticipate nothing curious in their internal configuration;—yet, where some parts are found double, and others single, the resources of nature become apparent in adjusting parts which have naturally no connexion. Such is the instance here described ; and it appears peculiarly interesting, from the consideration, that the system of deviation was apparently compatible with life; for if the difficulty of the birth had not proved almost immediately fatal, the complexity of the structure would probably have formed no impediment to its existence,

This curious production had two heads, placed side by side, united to one body, with two legs and two arms. The countenance of the one appeared to the author to be male, and of the other female; and the conformation of the organs of generation, which partook of both sexes, confirmed that persuasion.

The trunk, though appearing as one body, was broader than natu-