512 



imagined that other carbonaceous substances were oxides of diamond; 

 and Sir Humphry Davy himself supposed, on the contrary, that dia- 

 mond, as a non-conductor of electricity, probably contained oxygen, 

 and afterwards that it contained some new principle of the same class 

 with oxygen. 



Having, however, lately made some direct experiments on the com- 

 bustion of the diamond in oxygen gas, by means of the great lens 

 belonging to the Academy at Florence, his results have not differed 

 from those made by Mr. Tennant, and subsequently by Messrs. Allen 

 and Pepys, respecting the quantity or quality of the gas produced ; 

 and he acknowledges that the general tenour of his experiments is 

 opposed to the conjectures that have been entertained by himself and 

 others respecting the existence of oxygen, either in the diamond itself, 

 or in carbonaceous substances. His experiments likewise, so far from 

 supporting the hypotheses of Messrs. Biot and Arago as to the exist- 

 ence of hydrogen fis a constituent part of diamond, showed that a 

 minute quantity of hydrogen was really contained in each of the 

 other carbonaceous substances employed flbr comparison, not except- 

 ing plumbago. The presence of hydrogen in these bodies is most 

 distinctly shown on heating them in chlorine, by white fumes that 

 are immediately perceived in consequence of the production of mu- 

 riatic acid ; but when diamond is heated in the same gas, no such 

 vapour appears. In the course of these experiments the author no- 

 tices a phenomenon which he had not before seen, namely, that dia- 

 mond when once ignited in oxygen, continues to burn till it is con- 

 sumed. 



Some Account of the fossil Remains of an Animal more nearly allied 

 to Fishes than any of the other Classes of Animals. By Sir Everard 

 Home, Bart. F.R.S. Read June 23, 1814. [Phil. Trans. 1814, 

 p. 571.] 



The bones here spoken of, are from the cliff between Lyme and 

 Charmouth in Dorsetshire. The cliff, says the author, is composed 

 of limestone, upon which is a stratum of blue clay two or three feet 

 thick, in which these bones were deposited. 



A drawing has been made of these bones to accompany the paper, 

 which supersedes the necessity of a very particular description. Their 

 magnitude is such, that the head alone measures four feet. The upper 

 and under jaw are very distinct, set with small conical teeth, as in 

 the crocodile ; but the lower jaw is not articulated as in that animal, 

 but connected by an intermediate flat bone, as in fishes. The sclerotic 

 coat of the eye is also, as in fish, bony, but is subdivided, as in the 

 eyes of many birds, into a number of separate plates. The inter- 

 vertebral cavities of the spine likewise prove, that this skeleton is 

 that of a swimming animal ; since the form of each cavity is that of 

 an oblate oval, much wider in its transverse diameter than in the di- 

 rection of the spine. The niode of articulation of the lower jaw, which 

 admits of its being opened to a great extent, seems to show the animal 



