ferent from that in England, and not so expensive. At Arcachon tiles are used, to which the spat attaches itself when floating about the bay. Walls about eighteen inches high are made of the tiles on the mud-banks, which retain the water when the banks are dry at low tide. In these ponds the young oysters are kept after they are taken off the tiles.

At Auray the collectors of spat used are tiles, wooden boards nailed together, and slates. The wood seems to answer admirably well.

At L'Orient the apparatus of cultivation consists of what are called Michel's Patent Concrete Pans. These are about two and a half by one and a half feet, and eight inches deep, retaining the water when the tide is out. The young oysters remain in these pans, and the growth made in one year is very remarkable. The temperature of the water at L'Orient was sixty-eight degrees.

YARMOUTH AQUARIUM.

The new aquarium at Yarmouth, England, it is said, will be completed by June, 1876. Mr. Saville Kent, at present in charge of the Manchester aquarium, has been appointed manager and naturalist of the new establishment.

K. DOMESTIC AND HOUSEHOLD ECONOMY.

TRANSPARENT SOAP.

The most essential condition in the preparation of transparent soap, and one frequently overlooked, is that the soap employed shall be as nearly neutral as possible, as any free fatty acid present separates subsequently in clouds and flakes; while free soda, on the other hand, attracts carbonic acid from the air, forming crystals of carbonate of soda. The transparency of glycerin soap is also said to be improved by the addition of a small quantity of white sirup.15 C, XII., 191.

THE USE OF GAS FOR LIGHT-HOUSES.

The great advantage of employing gas for light-house purposes is stated to consist in the fact that, by a very simple arrangement, the number of burners and the brilliancy of the flame can be increased from its ordinary to an extraordinary brightness, such as to provide for its visibility in all kinds of thick weather, except, of course, that condition of fog which no light, not even the sunlight, can penetrate. In a fixed light apparatus, of any size, there is no occasion to alter the existing lenses if we wish to introduce the use of gas instead of oil; but in some lanterns it may be necessary to provide for additional ventilation. The cost of gas-light is said to be less than that of oil, while the photometric value of the flame of gas is largely superior to that of any kind of oil. When the "fog-power" of the gas-light is turned on; the cost of the gas per hour is greater; but taking the average of a year's consumption, at several lighthouses, it appears that there is an actual saving of about $300 per year by the use of gas. A very simple apparatus effects an automatic intermission in the light, which not only saves somewhat in the consumption of gas, but acts as a means of distinguishing one light-house from another, precisely as is at present brought about by the introduction of the flashing system. A gas-light of the first order, employing Mr. Wigham's gas-burners of 108 jets, would, if fixed, be

equal to 70,000 standard candles; but, if revolving, be equal to 873,000 candles.-Elliot's Light-house System, p. 169.

PRICE OF BURNING-GAS.

The following figures show the net price of illuminatinggas throughout the United States in 1875, upon the authority of the Washington, D. C., Gaslight Company:

Total average net price of gas in the United States, $4 324 per 1000 cubic feet.

A NEW LIGHT.

According to The Athenæum, Mr. Spiller has succeeded in producing a light far better than that from nitro-oxide and the bisulphide of carbon, and free from its dangers. This is accomplished by dropping small pieces of brimstone into fused saltpetre, in a glass tube.-15 A, Jan. 30, 1875, 166.

TREATMENT OF NEW WOODEN UTENSILS, ETC.

Wooden vessels for containing articles of food, wine, etc., also wooden vessels for culinary purposes, can be rendered fit for immediate use, as to the removal of the unpleasant extractive matters, by treatment with a solution of washingsoda. Thus an ordinary barrel should be filled half full of water, and a solution of about two pounds of soda in as much

water as will dissolve it, then headed, and the liquids thoroughly mixed by shaking the barrel, which should then be filled to the bung with water, and allowed to remain for from twelve to fourteen days; then, after withdrawing the discolored liquid, it should be well rinsed and filled with pure water and allowed to remain several days, when it will be fit for use. Other wooden utensils may be treated with a similar solution of soda.-8 C, Nov. 26, 1874, 422.

LAMP FOR BURNING NITRIC OXIDE GAS.

The brilliancy of the light produced by the combustion of nitric oxide gas, after mixture with a few drops of sulphide of carbon, has been known for some time, and its application to photographic purposes suggested; but it is not until recently that Messrs. Delachanal and Mermet have constructed an apparatus by which it can be made practically available. They use a lamp made of a pint bottle, having two openings through the cork, and filled with fragments of some porous substance, as sponge, coke, or pumice, for the purpose of imbibing the sulphide of carbon. A tube, reaching within one fourth of an inch of the bottom, passes through one opening in the cork, and a larger one through the other opening. This is about eight inches long, and may be of glass or metal, and is closely packed around with iron-scale. The object, like that of the gauze in the safety-lamp, is to prevent the return of the flame into the bottle, and its consequent explosion. The nitric oxide gas is passed into the bottle through the first-mentioned tube, and the gaseous mixture is conducted by a rubber tube to a kind of Bunsen burner, the air-holes of which are closed, and which is furnished with a small conical valve to regulate the flow of gas. This burner is also filled with iron-scale. The nitric oxide gas is produced in the cold by Sainte-Claire Deville's method, by the action of a mixture of nitric and sulphuric acids upon metallic iron. With an apparatus of quite moderate dimensions a dazzling flame, not less than ten inches. in height, can be obtained, abundantly sufficient for the purposes of photographic work. It has been estimated that the photographic power of the lamp is superior to that of magnesium, is twice as great as that of the oxyhydrogen light, and three times as great as that of the electric light. Fur

thermore, the flame is absolutely steady, and there is no danger of its sudden extinction, as with magnesium; and the eye can sustain its brilliance without being affected. Its cost is much less than that of either of the other lights.-1 D, Dec., 1874, 381.

NITRIC OXIDE-BISULPHIDE OF CARBON LAMP FOR PHOTO

GRAPHIC USE.

A lamp of the following construction, patented by Sell, in England, is said to afford a light very rich in the highly refrangible rays. Photographs have been taken by means of it, with a comparatively short exposure, which are said to be all that can be desired as to the distribution of light and shade. A small spherical glass vessel, filled with bisulphide of carbon, is supplied with a wick, by which it is fed to an ordinary Wild and Wessel burner, through the centre of which nitric oxide is admitted from a gasometer by means of a tube bent at right angles. This globe is inclosed in a larger one of glass, filled with cold water, to cool the bisulphide. Upon lighting the bisulphide, which can be done without danger, and then regulating the flow of nitric oxide and the height of the wick, a beautiful white light of great intensity may be produced.-14 C, CCXV., 1875, 384.

MERRIMAN'S WATER-PROOF LIFE-SAVING DRESS.

The following description is given of this invention, the useful character of which has been so admirably tested by Captain Boynton in his recent trial trips in the English Channel. The dress is composed of two principal parts: the upper portion consists of the shirt or jacket, a head-piece, sleeves and gloves, all in one piece, and made of rubber cloth or other water-proof materials. The lower portion is composed of pantaloons and boots of similar material, and also in one piece. The front of the head-piece, corresponding with the face of the wearer, is made highly elastic, and is provided with an aperture of suitable size to expose the eyes, nose, and mouth. The top, back, and sides of the head-piece are made double, forming a cavity for the purpose of admitting of expansion by inflation. The effect of this inflation is not only to support the head when in the water, but also to draw the elastic edges of the aperture tight about the face, thus