106 On Alimentary Matter from Bones. [Feb. 



aeriform state is at its minimum ; hence we see the reason why 

 they continue for so long a time without having their density 

 increased ; evaporation goes on from the upper surface, while 

 the ascending portions of air are adding to its bulk on the 

 inferior ; and unless the latter exceeds the former, the cloud 

 will remain stationary. But when the quantity of aqueous vapour 

 disengaged exceeds what is carried oft' from it by evaporation, 

 the vesicular vapour gravitates slowly downwards, and increas- 

 ing in bulk as it descends, constitutes that modification of cloud 

 called the cumulus. It would appear then that the cumulus 

 usually occupies that line of elevation at which the density of 

 the atmosphere is exactly equivalent to the weight of the vesi- 

 cular vapour joined with that of the air intermixed with it. 



It now only remains to remark, that this theory is not intended 

 to supersede the one given by Mr. Howard and others, respect- 

 ing a repulsion between the particles of vesicular vapour, in 

 consequence of their being similarly electrified ; but is only 

 meant to explain a circumstance which appears unaccounted 

 for by the electrical hypothesis ; namely, the reason why these 

 globules, even in their attenuated condition, maintain themselves 

 for so long a time in the still rarer atmosphere through which 

 they float. 



Should these remarks appear to you worth printing, you would 

 oblige a constant reader by inserting them in your next number. 



tftn,. 28. PuiLO-CHEMICUS OxONIENSIS. 



Article V. 



On the Alimentary Matter procured from Bones. 



In consequence of the scarcity of provisions which prevailed 

 at Geneva, as well as in so many other parts of Europe, during 

 the last year, the attention of the inhabitants was forcibly 

 directed to the various methods of procuring food, and among 

 others, to the nutriment supposed to be contained in bones. 

 A series of experiments on this subject was published some 

 time ago by Proust, and more lately by Cadet de Vaux ; but the 

 results which they obtained were not confirmed by some trials 

 that were made in this country, and seem to have been 

 scarcely credited. The Society for the Promotion of the Arts at 

 Geneva appear, however, to have been more successful ; they 

 have actually employed this method of providing food to a consi- 

 derable extent, and have published a detail of their processes 

 in the Bibliotheque Universelle for September last, from which 

 the following account is extracted. 



There are two distinct processes to which the bones are subr 



