.

Mr Nicholson, in the second number of his valuable Journal, tell us, that being informed by a philosophical friend, that the usual recipes for making this compound do not succeed, and that the use of mastic in it has hitherto been kept a secret, he made the following trials to procure a good eau de luce.

One dram of the rectified oil of amber was dissolved in four ounces of the strongest ardent spirit of the shops; its specific gravity being 840 at 60 degrees of Fahrenheit. A portion of the clear spirit was poured upon a larger quantity of fine powdered mastic than it was judged could be taken up. This was occasionally agitated without heat; by which means the gum resin was for the most part gradually dissolved. One part of the oily solution was poured into a phial, and to this was added one part of the solution of mastic. No opacity or other change appeared. Four parts of strong caustic volatile alkali were then poured in, and immediately thaken. The fluid was of a dense opaque white colour, affording a slight ruddy tinge when the light was seen through a thin portion of it. In a second mixture, four parts of the alkali were added to one of the solution of mastic; it appeared of a less dense and more yellowish white than the former mixture. More of the gum resinous solution was then poured in; but it still appeared less opaque than that mixture. It was ruddy by transmitted light. The last experiment was repeated with the oily solution instead of that of mastic. The white was much less dense than either of the foregoing compounds, and the requisite opacity was not given by augmenting the dose of the oily solution. No ruddiness nor other remarkable appearance was seen by transmitted light. These mixtures were left at repose for two days; no separation appeared in either of the compounds containing mastic; the compound, consisting of the oily solution and alkali, became paler by the separation of a cream at the top.

It appears, therefore, that the first of these three mixtures, subject to variation of the quantity of its ingredients, and the odourant additions which may be made, is a good eau de luce.

In a subsequent number of the same Journal, we have the following recipe by one of the author's correspondents, who had often proved its value by experience.

"Digest ten or twelve grains of the whitest pieces of mastic, selected for this purpose and powdered, in two ounces of alcohol; and, when nearly dissolved, add twenty grains of elemi. When both the resins are dissolved, add ten or fifteen drops of rectified oil of amber, and fifteen or twenty of essence of bergamot: shake the whole well together, and let the feces subside. The solution will be of a pale amber colour. It is to be added in very small portions to the best aqua ammoniae purae, until it assumes a milky whiteness, shaking the phial well after each addition, as directed by Maquer. The strength and cauacity of the ammoniae are of most essential consequence. If, upon the addition of the first drop or two of the tincture, a dense opaque coagulated precipitate is formed, not much unlike that which appears on dropping a solution of silver into water slightly impregnated with common salt, it is too strong, and must be diluted with alcohol. A considerable proportion of the tincture, perhaps one to four, ought to be employed to give the liquor the proper degree of opacity."in Architecture, the margin or edge of the roof of a house; being the lowest tiles, slates, or the like, that hangs over the walls, to throw off water to a distance from the wall.