imagined that other carbonaceous substances Were oxides of diamond;
and Sir Humpbry Davy himself supposed, on the contrary, that diamond, 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- bus Ion of the diamond in oxygen gas, by means of the great lens belonging ti), 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 Arngo as to the existcnce of hydrogen as a constituent part of diamond, showed that a minu 'quantity of hydrogen was really contained in each of the other darbonaceous stances employed {6r comparison, not excepting plumhago. 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.
The bones here spoken of, are from the cliff between Lyme and Charmauth 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 intervertebral 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 direction 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
