360 



to be present. The quantity of sulphate of barytes produced from 

 100 grains 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 muriate of soda, whether of English or foreign manufac- 

 ture. 



In addition to the author's 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 pan 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 Foetus. 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 otherwise, are by no means rare in the col- 

 lections 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 inter- 

 nal 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 de- 

 scribed ; 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 im- 

 pediment 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- 



