425 



distinct attachment of a rib on both sides to each vertebra by a ball 

 and socket-joint. It is remarked, that in this tribe of animals the 

 relative positions of the ball and socket are reversed from their usual 

 situation, the socket being attached to the extremity of the rib, and 

 fitted to a protuberance from the body of the vertebra, instead of the 

 extremity of the rib being applied to an indentation between two ad- 

 jacent vertebrae. Hence the ribs do not in any degree interfere with 

 the motion of the vertebrae upon each other, as in other animals. 



The muscles by which these motions are performed, are also de- 

 scribed by Mr, Home ; but the distribution of them cannot readily be 

 understood, without reference to the drawings which accompany the 

 paper. 



At the termination of each rib is a small cartilage, which rests for 

 its whole length on the inner surface of the corresponding abdominal 

 scutum, to which it is connected by a short muscle. 



The scutum being thus moved by a rib from each side, its posterior 

 edge lays hold of the ground, and becomes the support by which the 

 adjacent portion of the body is propelled forwards, and by a series 

 of alternate motions is capable of renewing the impulse with consi- 

 derable rapidity. 



Mr. Home remarks, that in the Draco volans the wings, by which 

 the animal flies, are supported by ribs, which form the skeleton of 

 them ; but in this instance the elongated ribs are superadded, for the 

 sole purpose of forming the wings, and do not, as in the snake, assist 

 in the process of respiration, at the same time that they are employed 

 in giving progressive motion. 



An Account of some Experiments on the Combinations of different 

 Metals and Chlorine, SfC. By John Davy, Esq. Communicated by 

 Sir Humphry Davy, Knt. LL.D. Sec. R.S. Read February 27, 

 1812. [Phil. Trans. 1812, p. 169.] 



The principal objects of these experiments is to determine the pro- 

 portions in which oxymuriatic acid or chlorine combines with various 

 metals ; but the author has also extended his inquiry to the relative 

 proportions, in which oxygen also, and sulphur, unite with some of 

 the same metallic substances. 



Of copper, Mr. John Davy notices two compounds, to which he 

 gives the names of Cuprane and Cupranea. The former is the same 

 as the resin copper of Boyle, which may be obtained by heating to- 

 gether one part of copper with two parts of corrosive sublimate. This 

 compound is also the same as that named by Proust, white muriate 

 of copper, who obtained it by mixing together muriates of tin and 

 copper ; and Proust observed that the same compound might be pro- 

 cured, by heat, from the common deliquescent muriate of copper. 



This compound is fusible by heat below redness, and in close ves- 

 sels is not decomposed by a strong red heat ; but if air be freely ad- 

 mitted, it is dissipated in white fumes. It is insoluble in water, but 



