tron of the ancient Egyptians, or the Native Soda of modern chemistry.-Professor Jameson then read an account of a new magnetical instrument called the Solar Compass, invented by Mark Watt, Esq., and exhibited the instrument itself.-[This interesting paper is printed in the present Number of this Journal, p. 16, et seq., and a figure of the Solar Compass is given in Plate I.]

SCIENTIFIC INTELLIGENCE.

METEOROLOGY.

1. Great Fall of Rain at Bombay.-In a letter from Mr Scott jun. of Bombay, he says, that, during the first twelve days of the rainy season, 32 inches of rain fell, and that then all the roads became like rivers. In England, the average fall for the whole year is 32 inches, the quantity which fell at Bombay in the course of twelve days.

2

HYDROGRAPHY.

2. Colour of the Red Sea.-The colour of the Red Sea has given rise to various investigations. Dr Ehrenberg, who accompanied Dr Hemprich, ascertained that it was caused by a species of Oscillatoria, one of those small plants which are intermediate between animals and plants.

3. Melted Snow employed as Drink.-A fact related by Captain Parry, proves that melted snow is not so unwholesome a drink as it has hitherto been supposed. He and his crew made use of it for three years without being affected with the glandular swellings to which, according to the common opinion, they should have been exposed by employing this beverage.

4. Notice regarding the Falls of Rewah, and a remarkable Conical Hill at Myhur.-I left Benares with my regiment on the 5th of October, and arrived at Jubbulpoor on the 9th of November 1826. Our route lay through Mizapoor, Rewah, and Myhur. When at Rewah, I left the corps for two days, and, in company with some of our officers and their ladies, went to visit the stupendous falls of the Lounse, or Loonse, generally called the falls of Rewah. They are three in number, and the

largest of them is allowed to be the grandest yet discovered, Niagara not excepted. You may hear the noise of the fall at the distance of many miles; but the sight which is presented to you on your nearer approach is grander than I can possibly find words to express. The water dashes over a perpendicular rock 173 feet high, in one unbroken stream; and the vapour which rises from the bottom appears like an immense cloud of white smoke, and will wet one to the skin 500 yards off. The second fall is not quite so grand in respect to height, but I think more beautiful in appearance. In the very middle of it stands a rock, in the shape of a tall pillar, and so slight that you would expect to see it washed over by the stream which continually dashes around it. The top of it may be about seven or eight feet in diameter; and on that pinnacle lives an old Fakeer, who has not been off it for the last thirty years. He is supplied with food by some of the neighbouring villagers, who regard him as constantly employed in contemplation of the deity. At Myhur we halted a day, which I spent in visiting the town, and some adjacent ruins, which are well worthy of note. About a quarter of a mile to the south-west of the town, there is a very curious hill, in the shape of a cone, very steep on all sides, and on the top of it is erected a small Hindoo temple, to which you ascend by a stair built in a straight line up one side of the hill, which is nearly perpendicular. It consists of 523 steps, each about 14 inches high. On going up I had to rest very frequently; and, on looking down, I sometimes felt myself so giddy, that had I not been supported by the bushes at each side, I dare say I should have rolled down to the bottom. This place was built long ago by one of the Myhur's Rajahs, and has always been looked upon by the Hindoos as a most holy spot. From thence to Jubbulpoor the country is almost all jungle, and the roads very bad; and we were all highly pleased when we arrived at the end of our journey.-Letter from an Officer of the 5th Extra Regiment of Native Infantry, to his Father.

NATURAL PHILOSOPHY.

5. Distances at which Sounds are heard.-I recollect of being, many years ago, at the west end of Dunfermline, and hearing part of a sermon then delivering at a tent at Cairneyhill. I

did not miss a word, although the distance must be something about two miles. It was the late Dr Black of Dunfermline who preached, and who perhaps has seldom been surpassed for distinct speaking and a clear voice. The sound was such as I should have expected, in favourable circumstances, at a quarter of a mile. The wind, which was steady, but moderate, came in the direction of the sound. There are some miraculous stories of sermons being heard at many miles distance; but I did not view it in that light. I was riding westward, and at length saw the Doctor finishing his sermon, otherwise I should have doubted whether he had been at such a distance. Whether the sound had run along the road, as in a tube, I cannot say. I recollect little of what sort of road it is; part, I think, has pretty good dikes, which might guide and confine the sound, aided by the wind. Some gaping ploughmen may surely be heard calling to their horses more than two miles; and, were fishwives in the open country, their eloquence would probably extend still farther. Unfortunately, most people, when they call loud, are not intelligible. In Scripture, there seem to be instances of persons being heard far speaking from mountain tops, but perhaps they used a trumpet.-H. M.

6. Capillary Action.-From a series of interesting experiments performed by Magnus, and recorded in Poggendorf's Journal, St. 5. 1827, it follows, that the rising of fluids through a bladder, as detailed in some well known experiments, is an effect of capillary action, and that it can be explained, if we admit that different fluids force their way through capillary openings more or less easily, according to their degree of tenuity.

7. Farther Observations made on the Solar Compass.-1. That the effect produced by the hairs or piles of velvet is much greater when the velvet is placed over the points of the needle, than when it is made to surround the circle of cork into which the needles are fixed. 2. That it seems a farther improvement to place south and north poles alternately outwards. 3. I have twice observed it move about 10° to the influence of the full moon, when the atmosphere was very clear. 4. That its sensibility seems greatly diminished by cold, and that when the thermometer stood at 30° in the shade, it did not move to the influence of the sun at this season, above three hours, from 11 A. M.

to 2 P. M. 5. That, at this season of the year (November), a circle of cork, with 20 or 30 needles fixed inside of the circle, having all their points nearly meeting at the centre, and suspended by any very tenuous filament, is more sensitive than that form of the instrument which traverses on a pivot.-M. W.

CHEMISTRY.

8. Metal of Alumina.-M. Oersted is stated to have obtained the metal of alumina, by employing the chloride of that earth. Pure alumina is heated to redness, and then intimately mixed with powdered charcoal; the mixture is introduced into a porcelain tube; and, after heating to redness, dry chlorine gas is passed over it. The charcoal reduces the alumina, the metal combines with the chlorine, and oxide of carbon is also formed. The chloride of aluminum is soft, crystalline, and evaporates at a little above the temperature of boiling water; it readily attracts moisture from the air, and becomes hot when water is added to it. By mixing with an amalgam of potassium, containing much of the latter, and immediately heating the mixture, chloride of potassium is formed, and the metal of the alumina combines with the mercury. The amalgam quickly oxidises by exposure to the air. Being subjected to distillation, out of the contact of air, the mercury is volatilized, and a metallic button is left, which has the colour and splendour of tin. M. Oersted has ascertained many properties belonging to the new metal, and its amalgam, which he promises to publish speedily.-Phil. Mag. Nov. 1827.

MINERALOGY.

9. Largest known masses of Native Platina.-Before Humboldt's return from America, small grains only of platina were known to naturalists. On his arrival in Prussia, he deposited in the Berlin Museum a native specimen of Peruvian platina, weighing 1083 grains. For twenty years, this remained the largest specimen in Europe. Since 1822, the Museum of Madrid has been enriched with another American mass of platina, weighing 11,641 grains. A few months ago, a still more remarkable mass was discovered in the Urals, weighing 105 Russian pounds. It is deposited in the Museum of St Peters

burg. The relative weights of the platina of Berlin, Madrid and Petersburg are as 1, 11, 75.

10. On the Ostrunite, a New Mineral Species; by Aug. Breithaupt. This substance has only as yet been found in the crystallized state, and in the form of a right rhomboidal prism, slightly modified on the acute lateral edges, and deeply truncated on the angles of the bases. M. Breithaupt derives this form from a rhomboidal octahedron, in which the three axes are to each other as the numbers 1000, 2059, and 1854. The adjacent faces on the same pyramid form between them angles of 128° 14, and 133° 42'. Their inclination upon the base is 71° 56'. The angles of the rhomboidal prism are 96° and 48°. There is a scarcely perceptible cleavage parallel to the small diagonal of the base. The lustre of the ostranite is vitreous; its colour is clovebrown. Its hardness is intermediate between that of orthoklase and quartz. It is very brittle; its specific gravity varies between 4.32 and 4.40. The crystals of this substance, which served as a basis to the preceding determination, were about an inch long; they formed part of the collection of the Chev. Heyer, of Dresden. They came from Norway, whence they were brought by M. Nepperschmidt, of Hamburg. Nothing is known precisely with regard to their geognostical relations. Some trials of this substance have been made with the blowpipe. Treated alone, it does not melt, but its colour becomes paler. With borax it melts, but with difficulty, into a transparent glass; it is insoluble in nitric acid. From these characters, and the place which it occupies in the system, M. Breithaupt presumes that this substance is a new metallic oxide. He gives it the name of ostranite, derived from that of the goddess Ostra, in order that, should a new metallic base be discovered in this oxide, the name of Ostran may be given it, as has been done with regard to titanium and titanite, tantalum and tantalite, &c.

11. On the Rose-coloured Petrosilex of Sahlberg; by M. Berthier.-M. Berthier proposes to submit to a chemical examination the petrosilex of Sahlberg, in Sweden. This mineralogist observes, that the petrosilexes are erroneously considered as varieties of compact felspar. It is one of those vague denominations with which science is still disfigured, and which only serve to lead into error, or to deceive us with regard to what we are ig