the distribution of rocks. With respect to the first two of these branches, we have no details; but a table is given of the distribution of rocks. They are divided into six classes, namely: I. Mountains in Mass. They are all composed of the oldest granite. II. Mountains in Beds. Notwithstanding the great length of this list, I have omitted all the subordinate formations, which are very numerous. The great mistake into which Tondi appears to have fallen in the preceding classification is the confounding together, as of equal importance, those substances which occur in great abundance, constituting rocks, or mountains, of considerable extent, with those substances which occur only in minute quantities scattered through the first. No classification can be of much value to the practical geognost, unless this distinction is carefully attended to. anotedmils ARTICLE XIV. SCIENTIFIC INTELLIGENCE; AND NOTICES OF SUBJECTS 1. Galvanic Battery. On Saturday, the 2d of July, J. G. Children, Esq. put in action the greatest galvanic battery that has ever been constructed. It (consisted of 20 pair of copper and zinc plates, each plate 6 feet in length, 2 feet 8 inches in breadth Each pair was fixed together at the top by pieces of lead cut into ribbons. A separate wooden cell was constructed for each pair. plates were suspended from a wooden beam fixed at the ceiling, and were so hung by means of counterpoises that they could be easily raised or let down into the cells. The cells were filled with water, containing a mixture of sulphuric and nitric acids. At first the acids amounted to 1-60th of the water; but more was gradually added till it amounted to the 30th. Leaden pipes were attached to the two extremities of the battery, and conveyed the electricity out of doors to an adjoining shade, where the experiments were made. The power of this battery was very great; though I am not certain whether it increased in proportion to the size of the plates. It ignited about 6 feet in length of thick platinum wire. The heat produced was very intense. It melted platinum with great facility. Iridium was likewise melted into a globule, and proved to be a brittle metal. The ore of iridium and osmium was likewise melted, but not so completely. Charcoal was kept in a white beat in chlorine gas, and in phosgene gas; but no change took place in either of these gases. Neither tungsten nor uranium underwent any change. A very singular fact was pointed out by the sagacity of Dr. Wollaston, and succeeded upon trial. A greater length of thick platinum wire was ignited than of platinum wire of a much smaller size. This Dr. Wollaston had previously ascertained in his own minute galvanic batteries, consisting of a single pair of small plates. II. Volatility of Cerium. The volatility of this metal, which had been previously inferred from the experiments of Vauquelin, was fully confirmed in Mr. Children's laboratory at Tonbridge. A quantity of oxalate of cerium had been prepared in order to obtain from it the oxide of the metal. This oxalate was within a tobacco-pipe mou to thesed in a charcoal crucible strongest heat that could be raised in a forge. In this heat the cerium was volatilized so completely that not the least trace of it remained. 1909 III. Action of the Agate on Light. Dr. Brewster has now established, by numerous experiments, that the nebulous light of the agate has the same relation to the bright image as the extraordinarily refracted image has to the ordinarily refracted image of all doubly refracting crystals. There is still, however, no appearance of the nebulous light being produced by a higher refractive power than the bright image. All the phenomena of polarization are produced when the plate of agate is less than theth of an inch; and the nebulous light, when in its evanescent state, can be revived by depolarization with mica, in every respect like one of the images formed by double refraction. The coloured appearances in the agate, to which mineralogists have given the name of iridescence, furnish a series of the most singular results, arising, apparently, from the mechanical structure of different laminæ, and seem to open up a new field in physical opties. He is at present examining various specimens, in order to give a greater degree of generality to the results previous to laying them before the public. 1 IV. Transition Rocks in Yorkshire. I have received the following letter, which I lay before the public; because I consider every fact that adds to our knowledge of the mineralogical structure of Great Britain as interesting. I have myself seen most of the places referred to in the letter, but had no opportunity of determining the structure of them with any thing like accuracy; nor was I aware that any transition formations occurred upon the east coast of Yorkshire. 36. SIR, In the Annals of Philosophy, No. VI. Article II. " On Transition Rocks," the writer mentions, that he knows of no transition rocks to the east of a line extending almost due south from Berwick to the English Channel. " - Knowing from ****, and others, that you have visited Yorkshire, and given particular attention to the geology of the county, I presume that you are well acquainted with the under stratum of the Wolds, and therefore that the lines I have quoted have escaped your observation, or would have been accompanied with your remark, noticing the transition limestone of that district. is of very The chalky limestone stratum of the Wolds, of which Flambro Head is the most easterly point, and Leavening Brow the most westerly, is of very considerable depth, as the cliff from Flambro to Spector, and the wells that have been made for obtaining water, indubitably prove. The cliff at Spector appears to the eye at least 400 feet perpendicular, and is one entire bed of the same stone, not intersected by any veins whatever, and containing various shells wherever a quarry is opened in this extensive stratumez od sed elus od 1 bal evol Flambro Head and Filey Bridge are the two most easterly points of the bay generally called Filey Bay. From Flambro' Head to Spector the white cliffs of Albion appear for the last time in sailing to the North; and at Filey Bridge the dark colour of the moorstone district begins, which continues to the most northerly point of Britaingo dt sdt uit Filey Bridge has been formed by the Ocean gradually washing off an immense bed (100 feet thick) of argillaceous earth from the rocky base, which dips in a southerly direction; and in the highest part is not more than 50 or 60 feet above high water mark. This base I call a firm argillaceous sandstone; it is in large blocks, containing shells, and intersected by grey limestone in thin strata, from 6 to 18 inches, containing also various shells, particularly the large ostrea, and dipping at the same angle, and in the same direction; the angle about 15 degrees. Should these observations recal to your memory the minutes you would of course make in your geological view of the East Riding of Yorkshire, perhaps you will favour the county with a publication of them, at some convenient opportunity, in the Annals of Philosophy. This, I am sure, will oblige your Yorkshire friends; and particularly, Sir, Me of D-TA Your most obedient servant, 7 July 7, 1813. The following letter deserves to be laid before the public, because it forms what I consider as a valuable addition to Dr. Wollaston's ingenious explanation of the structure of crystals from spherical particles of matter. SIR, Dr. Wollaston, in the Bakerian Lecture published in the Philosophical Transactions, shows very ingeniously in what manner the regular tetrahedron and octahedron may be formed of spherical particles, |