6373. To Prevent Lamp Chimneys from Cracking

6373.    To Prevent Lamp Chimneys from Cracking. Put the chimneys into a kettle of cold water, and gradually heat it until it boils, and then let it as gradually cool; the chimneys will not be broken by the ordi nary fluctuation of the flame of the lamp.

6374. To Mend Rubber Overshoes, etc.

6374.      To Mend Rubber Overshoes, etc.. Rub the patch and shoe thoroughly with sharp sand paper. Smear both with liquid rubber 5 times, every time letting them dry. Do this once more, and, before they dry, apply the patch, with pressure if possible, and the boot is mended. If liquid rubber is not obtainable, dissolve small pieces of pure rubber (not vulcanized), in warm spirits of turpentine, to the consistence of syrup.

6375. To Preserve and Restore Oil Paintings

6375.    To Preserve and Restore Oil Paintings. Many valuable paintings suffer premature decay from the attacks of a microscopic insect of the mite class. The best method of preventing this species of decay is to add a few drops of creosote to the paste and glue used to line the picture, as well as to make a similar addition to the varnish. If it has already commenced, the painting should be at once carefully cleaned and relined, observing to employ a little creosote in the way just mentioned. Paintings should be kept in as pure an atmosphere as possible, and in a moderately dry situation; as it is the presence of sulphuretted hydrogen in the air that blackens the " lights," and causes most of the middle tints and shades to fade ; and it is exposure to damp that produces mouldiness and decay of the canvas. For this reason valuable paintings should not be kept in churches, nor suspended against heavy walls of masonry, especially in badly ventilated buildings. Excess of light, particularly the direct rays of the sun, also acts injuriously on paintings. The blackened lights of old pictures may be instantly restored to their original hue by touching them with deutoxide of hydrogen, diluted with 6 or 8 times its weight of water. The part must be afterwards washed with a clean sponge and water.

6376. Compressed Leather

6376.    Compressed Leather. A new process for using the clippings and refuse from saddlers' and shoemakers' shops is as fol lows: The leather shavings are washed clean, cut up fine, and soaked in water and sulphuric acid, 1 per cent, of the acid being sufficient. The immersion must continue till the shavings become plastic, and the leather then can be pressed into moulds with only a moderate amount of pressure. It can be rolled into thin sheets, and will be useful for many purposes; it will not, however, resist moisture. A little glycerine rubbed in will prevent its cracking.

6377. To Render Walls Water-tight

6377.    To Render Walls Water-tight. It is proposed by Mr. F. Ransome, of London, to render stone and brick walls waterproof by coating them to saturation with a solution of silicate of soda, which is superficially decomposed by the farther application of chloride of calcium. The surface thus obtained consists of silicate of lime, which is perfectly insoluble, and therefore water-tight, while it does not alter the appearance of the wall. (See No. 2171 (Cement for Rooms).)