Practical Hints. ry 
Acid-Proof Cement.—How to make a paste or cementing 
material, that is proof against acid fumes—like those given off in 
the preparation of nitrate of silver, for instance—is well worth 
knowing. Finely-powdered glass, mixed with soluble silicate of 
soda, will give a material of this description. 
Washing Fluid.—Take five quarts of water, half-pound of 
lime, and one pound of sal-soda, and let it come to a boiling 
point ; then settle, pour off, and bottle. Use one and a half cups 
of this to a washing of five persons. Soak the clothes in cold 
water over-night. After putting the fluid in a boiler of cold 
water, let it come to a boiling point; put in the clothes and _ boil 
half-an-hour. If any rubbing is required, it will be very easy. 
Then rinse them in two waters. ‘The above will not injure the 
clothes. 
To Destroy Flies—Half-a-teaspoonful of black pepper, one 
teaspoonful of brown sugar, and one tablespoonful of cream ; 
mix them well together, and place on a plate in a room where the 
flies are troublesome, and they will soon disappear. 
To Remove Ink-Stains from Books.—First wash the paper with 
warm water, using a camel’s-hair pencil for the purpose. By this 
means the surface-ink is got rid of. ‘he paper must next be 
wetted with a solution of oxalate of potash, or, better still, oxalic 
acid, in the proportion of one ounce to half-a-pint of water. The 
ink-stains will immediately disappear. Finally, again wash the 
stained paper with clean water, and dry it with white blotting- 
paper. 
Economical Gilding.—To gild works of art in bronze, gas- 
fittings, etc., the following mixture is recommended :—2$ pounds 
of cyanide of potassium, 5 ounces of carbonate of potassa, and 
2 ounces of cyanate of potassa; the whole to be diluted in 5 pints 
of water, containing in solution }-ounce of chloride of gold. The 
mixture must be used at boiling heat, and, after it has been applied, 
the gilt surface must be varnished over. 
Artificial Marble.—This can be made by soaking plaster of 
Paris in a solution of alum; bake it in an oven, and then grind it 
toa powder. In using, mix it with water; and to produce the 
clouds and veins, stir in any dry colour you wish. It will become 
very hard, and is susceptible of a high polish. 
Marine Glue.—This glue is employed where the materials are 
exposed to the influence of wet. It cements not only wood, but 
glass and metals. It is made by dissolving by heat, one part of 
pure India-rubber in naphtha; the India-rubber being cut very 
small. When melted, two parts of shellac are added, and the 
melting continued until the whole is well mixed by occasional 
