440 



and his descriptions are accompanied with drawings of various pecu- 

 liarities of structure. 



Of the birds that live on animal food, the author has examined 

 several kinds of falcon, the Soland goose, the crane, the cormorant, 

 the common gull, and the snow-bird, the last of which differs con- 

 siderably from the rest. 



Among graminivorous birds, the swan and goose are noticed as 

 differing from most others in the situation and structure of these 

 glands. Others of this tribe here examined are the turkey, the cas- 

 sowary, the American ostrich, and the African ostrich. In the three 

 last the solvent glands are in a cavity of unusual size ; and the mus- 

 cular structure of the gizzard is uncommonly weak, which the author 

 conceives to be connected with the mode of progressive motion, which 

 is the same in these birds, and may serve to grind the food without 

 the assistance of strong muscular action. 



On some Combinations of Phosphorus and Sulphur, and on some other 

 Subjects of Chemical Inquiry. By Sir Humphry Davy, Knt. LL.D. 

 Sec. R.S. Read June 18, 1812. [Phil. Trans. 1812,^. 405.] 



The author has formerly described to the Society two compounds, 

 consisting of phosphorus and oxymuriatic acid, or chlorine ; one of 

 them is a solid compound ; and by his present experiments, consists 

 of three parts of phosphorus combined with twenty of chlorine. The 

 second compound contains only half this quantity of chlorine, and is 

 a fluid, having the specific gravity of T46. The fluid will also dis- 

 solve a still further quantity of phosphorus ; but the author has not 

 ascertained whether there is any definite limit to the proportion so 

 dissolved. 



When this fluid compound is treated with water, it forms a thick 

 fluid, of the consistence of syrup, that crystallizes slowly by cooling. 

 These crystals may be called hydrophosphorous acid ; for by heat they 

 ara decompounded into phosphoric acid, and a peculiar gas, consist- 

 ing of phosphorus and hydrogen. This gas differs from common 

 phosphuretted hydrogen, in not being spontaneously inflammable 

 when mixed with common air, and in being considerably less fetid 

 than that gas. The proportions of its constituent parts are estimated 

 to be four hydrogen, with twenty phosphorus. The phosphoric acid 

 contained in the crystals, derived its origin from the water added to 

 the original fluid; while the hydrogen of the water escaped with the 

 chlorine in the form of muriatic gas. 



In the interchange of elements which takes place in these combi- 

 nations, there are many circumstances favourable to ascertaining the 

 proportions in which the several elements unite with each other ; 

 and the author observes, the results accord remarkably well with 

 other determinations. 



In the same manner respecting sulphur, a similar accordance be- 

 tween the proportions, by weight, in which it unites with different 

 elements, confirms other estimates of the elementary number fit to 



