Dripread - Book

Thoroughly ventilate the areas by means of air bricks or other suitable connections with the outer air, and connect with one another by making through connections underneath the floor joists. Be very careful that the main wall is laid on a good and efficient damp course. The top of the space between the area and main walls may be covered in all around the building with bricks--ornamented or otherwise, as preferred--on a line just above the ground. Another plan of effecting the same object is to dispense with the area wall and in building the brick work to cover the whole of the work on the outside with a thick layer of bituminous asphalt. The plaster on the inside is in this case often rendered in nearly neat Portland cement.

How to Caseharden Large Pieces of Steel.--A box of cast or wrought iron should be provided large enough to hold one or two of the pieces, with sufficient room all around to pack well with the casehardening materials, which may be leather scrap, hoof shavings, or horn shavings, slightly burned and pulverized, which may be mixed with an equal quantity of pulverized charcoal. Pack the pieces to be casehardened in the iron box so as not to touch each other or the box. Put an iron cover on the box and lute with clay. Heat gradually in a furnace to a full red, keep at an even temperature for from 2 to 4 hours, raise the heat to a cherry red during the last hour, then remove the cover and take out the pieces and plunge endwise vertically in water at shop temperature; 2 per cent. of hydrochloric acid in the water improves its tempering qualities and gives the metal an even gray color.

A Good and Cheap Preparation to Put on Friction Matches.--The igniting composition varies with different makers. The following recipes may be taken as fairly representative, the first being the best: 1. Phosphorus by weight, 1/2 part; potassium chlorate, 4 parts; glue, 2 parts; whiting, 1 part; finely powdered glass, 4 parts; water, 11 parts. 2. Phosphorus by weight, 2 parts; potassium chlorate, 5 parts; glue, 3 parts; red lead, 1-1/2 parts; water, 12 parts. 3. A German mixture for matches. Potassium chlorate, 7.8 parts; lead hyposulphite, 2.6 parts; gum arabic, 1 part.

To Find How Much Tin Vessels Will Hold.--For the contents of cylinders: Square the diameter, and multiply the product by 0.7854. Again, multiply by the height (all in inches). Divide the product by 231 for gallons. For the frustum of a cone: Add together the squares of the diameters of large and small ends; to this add the product of the diameter of the two ends. Multiply this sum by 0.7854. Multiply this product by the height (all in inches). Then divide by 231 for the number of gallons.

A Useful Recipe.--For stopping the joints between slates or shingles, etc., and chimneys, doors, windows, etc., a mixture of stiff white-lead paint, with sand enough to prevent it from running, is very good, especially if protected by a covering of strips of lead or copper, tin, etc., nailed to the mortar joints of the chimneys, after being bent so as to enter said joints, which should be scraped out for an inch in depth, and afterward refilled. Mortar protected in the same way, or even unprotected, is often used for the purpose, but it is not equal to the paint and sand. Mortar a few days old (to allow refractory particles of lime to slack), mixed with blacksmith's cinders and molasses, is much used for this purpose, and becomes very hard and effective.

Test for Hard or Soft Water.--Dissolve a small quantity of good soap in alcohol. Let a few drops fall into a glass of water. If it turns milky, it is hard; if not, it is soft.

Test for Earthy Matters or Alkali in Water.--Take litmus paper dipped in vinegar, and if, on immersion, the paper returns to its true shade, the water does not contain earthy matter or alkali. If a few drops of syrup be added to a water containing an earthy matter, it will turn green.

Test for Carbonic Acid in Water.--Take equal parts of water and clear lime water. If combined or free carbonic acid is present, a precipitate is seen, to which, if a few drops of muriatic acid be added, an effervescence commences.

Test for Magnesia in Water.--Boil the water to a twentieth part of its weight, and then drop a few grains of neutral carbonate of ammonia into a glass of it, and a few drops of phosphate of soda. If magnesia be present, it will fall to the bottom.

Test for Iron in Water.--1. Boil a little nutgall and add to the water. If it turns gray or slate, black iron is present. 2. Dissolve a little

Burroughs' Encyclopaedia of Astounding Facts and Useful Information, 1889