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1817.]

instrument, called a Capillary Hydrometer, for measuring the strength and specific gravity of spirituous liquors, has lately been invented by Dr Brewster. The principle of the instrument is to determine the specific gravity from the number of drops contained in a small glass bulb, so that we have only to fill this bulb with any mixture of alcohol and water, and count the number of drops necessary to empty it. When a bulb about 1 inch in diameter was filled with water, it yielded only 724 drops, whereas, with ordinary proof spirits, it yielded 2117 drops, giving no fewer than a scale of 1393 drops for measuring specific gravities from 0.920 to 1.000. A correction must be made for temperature as in all other instruments.

A remarkable fossil has lately been discovered in the parish of Alford, in the county of Surrey, some miles east of Guildford. It was found about eight feet under the surface in a bed of clay. Above the clay, in that particular part, is a bed of gravel, which extends to a considerable distance east and west, and varies in breadth from eleven yards to about forty, and has the appearance of having been the bed of a river. The fossil consists of hard clay covered with thin rectangular scales, lying in a regular order, about of an inch long and  broad. These scales have been analyzed by Dr Thomson, and found to consist of

This is nearly the composition of the scales of fishes as determined by Mr Hatchet.

A new mineral, consisting of sulphate of barytes and carbonate of strontian, has been lately discovered at Stromness, in the Orkney Islands, by Dr Thomas Traill of Liverpool. An account of the analysis of this mineral by Dr Traill, was read at one of the late meetings of the Royal Society of Edinburgh. He proposes to call it barystrontianite from its composition, or stromnessite from its localityN. B. We have seen specimens of this mineral, and conjecture that it is a compound of the two known species, carbonate of strontian and sulphate of barytes, and that with care the two minerals might be separated from each other.

A new artificial horizon has lately been invented by Mr White of Kinross, of which an account will be found among our Original Communications.

Mr W. K. Northall of Wolverhampton announces, that he has discovered a new method of propelling boats by steam. The velocity of the boat may, by this plan, be easily increased from three to seven miles an hour. The weight of the machinery will not be more than three tons, and the space it will occupy is comparatively small.

Mr J. B. Emmett of Hull has published some experiments, which he made during the summer of last year, with the view of ascertaining whether a gas might not be obtained from oil, equal to that obtained from coal, so as to prevent the injury threatened to the Greenland trade by the rapidly increasing use of the latter in the lighting of towns, &c. By distilling various oils, previously mixed with dry sand or pulverized clay, at a temperature little below ignition, he obtained a gas which appeared to be a mixture of carburetted hydrogen and supercarburetted hydrogen gases. This gas produces a flame equally brilliant, and often much more brilliant than that produced from coal. It differed very little in quality, whether obtained from mere refuse, or from good whale sperm, almond or olive oil, or tallow. The gas, when burnt, produces no smoke, and exhales no smell or unpleasant vapour. Whatever oil is used, it evolves much more light when burnt as gas than when consumed as oil; in the latter case, the flame is obscured by a quantity of soot; in the former, the soot remains in the distilling vessel, and the flame burns with a clear light.

The water of the ebbing and flowing spring lately discovered in the harbour of Bridlington, Yorkshire, and described in the Philosophical Transactions for 1815, by Dr Storer, has been found to possess many excellent properties, and been administered with decided benefit in numerous cases of chronic disease. It has been analyzed by Mr Hume of Long-Acre, who finds that great purity is one of its most distinguishing properties, in which it may vie with Malverne well; that although this stream is so nearly connected with the sea, which covers its whole vicinity twice a-day, yet it is altogether free from muriate of soda, every kind of sulphate, and magnesia. It is little heavier than distilled water, and contains no other aeriform substance than carbonic acid. The solid contents of a wine gallon amount to 13 grains, consisting of carbonate of lime, 3.750; silex, and a little oxide of iron, about .125.

The Rev. F. H. Wollaston has submitted to the Royal Society a description of a thermometer constructed by him, for determining the height of mountains, instead of the barometer. It is well known, that the temperature at which water boils diminishes as the height of the place increases at which the experiment is made; and this diminution was suggested, first by Fahrenheit, and afterwards by Mr Cavendish, as a medium