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of acid; then it is dried, and is the purified steatite powder used for lubrication. It is not used alone, but is mixed with oils and fats, in the proportion of about 35 per cent. of the powder, added to paraffine, rape, or other oil. This steatite powder, mixed with any of the soapy compounds, which are also now used, in many cases, for lubrication, also answers a good purpose. It is chiefly intended for heavy machinery, such as the journals of water-wheels, railway and other carriages. Ransome's Artificial Stone.

Make sand or gravel into a paste with fluid silicate of soda (water-glass), mould it to the desired shape, and dip into a solution of chloride of calcium. This solution is made by neutralizing muriatic acid with lime, chalk, limestone, or marble. The mass becomes solid in a few minutes, and is exceedingly strong and durable .

To Imitate Ground Glass.

A ready way of imitating ground glass is to dissolve Epsom salts in beer, and apply with a brush. As it dries it crystallizes.

To Drill Glass.

Wet an ordinary drill with petroleum or benzine; turpentine will answer, but not so well; it will then bore common glass nearly as rapidly as steel. If it is intended to bore through, the glass should be first countersunk on each side with a drill dressed off so as to form a very flat threesided pyramid. Flint and plate-glass are very difficult to bore.

A New Kind of Electric Machine.

The electro-magnetic coil has, in a great measure, superseded the electric machine; the latter, however, will never cease to be an object of interest; and, it is probable, will always be preferred for some purposes. The expense and difficulty of managing large plates and cylinders of glass have hitherto been obstacles to the use of large electric machines. These obstacles appear now removed - glass being rendered unnecessary by the discovery of a far more convenient and effective material. M. Edmond Bequerel exhibited to the Academy of Sciences on a recent occasion an electric machine, the plate of which was made of indurated red sulphur, the invention of a civil engineer. It was 80 centimetres in diameter, and afforded a spark 14 centimetres in length. Noamalgamated cushions were required with it, the skin of a cat being quite sufficient to produce every desired effect. Sulphur undergoes extraordinary changes by successive fusions; becoming extremely hard and tenacious. After the third fusion it no longer acts on metals, or possesses its characteristic odor.

The plate used by M. Bequerel was formed by fusing the sulphur 3 times in a cast-iron vessel, at a temperature between 250° and 300° Cent., and allowing it, after each fusion, to cool thoroughly.

After the 1st and 2nd fusions it was crushed to a coarse powder; and, after the 3rd, it was poured into a plaster-mould. Plates, 4 metres in diameter, may easily be made in this way; they cost extremely little; and, besides being more efficient, are far less hygrometric than glass.