Part 439

Cement, 380 pounds $1.50 Sand and gravel, 1,500 pounds 0.19 ────── Total $1.69

or 11.5 cents per cubic foot solid concrete. Now, blocks 9 inches high and 32 inches long make 2 square feet of face of wall, each. Blocks of this height {699} and length, 8 inches thick, make 1 1⁠/⁠3 cubic feet of wall; and blocks 12 inches thick make 2 cubic feet of wall. From these figures we may calculate the cost of materials for these blocks, with cores or openings equal to 1⁠/⁠3 or 1⁠/⁠2 the total volume, as follows:

Per cubic foot of block, 1⁠/⁠3 opening 7.7 cts. Per cubic foot of block, 1⁠/⁠2 opening 5.8 cts. Block 8 x 9 x 32 inches, 1⁠/⁠3 opening 10.3 cts. Block 8 x 9 x 32 inches, 1⁠/⁠2 opening 7.7 cts. Block 12 x 9 x 32 inches, 1⁠/⁠3 opening 15.4 cts. Block 12 x 9 x 32 inches, 1⁠/⁠2 opening 11.6 cts.

If one-third of the cement is replaced by hydrate lime the quality of the blocks will be improved, and the cost of material reduced about 10 per cent. The cost of labor required in manufacturing, handling, and delivering blocks will vary with the locality and the size and equipment of factory. With hand mixing, 3 men at an average of $1.75 each will easily make 75 8-inch or 50 12-inch blocks, with 1⁠/⁠3 openings, per day. The labor cost for these sizes of blocks will therefore be 7 cents and 10 1⁠/⁠2 cents respectively. At a factory equipped with power concrete mixer and cars for transporting blocks, in which a number of machines are kept busy, the labor cost will be considerably less. An extensive industry located in a large city is, however, subject to many expenses which are avoided in a small country plant, such as high wages, management, office rent, advertising, etc., so that the total cost of production is likely to be about the same in both cases. A fair estimate of total factory cost is as follows:

Material Labor Total 8 x 32 inch, 1⁠/⁠3 space 10.3 7 17.3 cts. 8 x 32 inch, 1⁠/⁠2 space 7.7 6 13.7 cts. 12 x 32 inch, 1⁠/⁠3 space 15.4 10.5 25.9 cts. 12 x 32 inch, 1⁠/⁠2 space 11.6 9 20.6 cts.

With fair allowance for outside expenses and profit, 8-inch blocks may be sold at 30 cents and 12-inch at 40 cents each. For laying 12-inch blocks in the wall, contractors generally figure about 10 cents each. Adding 5 cents for teaming, the blocks will cost 55 cents each, erected, or 27 1⁠/⁠2 cents per cubic foot of wall. This is less than the cost of common brick, and the above figures show that this price could be shaded somewhat, if necessary, to meet competition.—S. B. Newberry in a monograph issued by the American Association of Portland Cement Manufacturers.

«Artificial Marbles.»—I.—The mass used by Beaumel consists of alum and heavy spar (barium sulphate) with addition of water and the requisite pigments. The following proportions have been found to be serviceable: Alum, 1,000 parts; heavy spar, 10 to 100 parts; water, 100 parts; the amount of heavy spar being governed by the degree of translucence desired. The alum is dissolved in water with the use of heat. As soon as the solution boils the heavy spar is mixed in, stirred with water and the pigment; this is then boiled down until the mixture has lost about 3 per cent of its weight, at which moment the mass exhibits a density of 34° Bé. at a temperature of 212° F. The mixture is allowed to cool with constant stirring until the substance is semi-liquid. The resultant mass is poured into a mold covered on the inside with several layers of collodion and the cast permitted to cool completely in the mold, whereupon it is taken out and dried entirely in an airy room. Subsequently the object may be polished, patinized, or finished in some other way.

II.—Imitation Black Marble.—A black marble of similar character to that exported from Belgium—the latter product being simply prepared slate—may be produced in the following manner: The slate suitable for the purpose is first smoothly polished with a sandstone, so that no visible impression is made on it with a chisel—this being rough—after which it is polished finely with artificial pumice stone, and lastly finished with extremely light natural pumice stone, the surface then presenting a soft, velvet-like appearance. After drying and thoroughly heating the finely polished surface is impregnated with a heated mixture of oil and fine lampblack. This is allowed to remain 12 hours; and, according to whether the slate used is more or less gray, the process is repeated until the gray appearance is lost. Polishing thoroughly with emery on a linen rag follows, and the finishing polish is done with tin ashes, to which is added some lampblack. A finish being made thus, wax dissolved in turpentine, with some lampblack, is spread on the polished plate and warmed again, which after a while is rubbed off vigorously with a {700} clean linen rag. Treated thus, the slate has the appearance of black marble.

STONE CEMENTS: See Adhesives.

STONE CLEANING: See Cleaning Preparations and Methods.

STONES FOR SHARPENING: See Tool Setting and Whetstones.

STONES (PRECIOUS), IMITATION OF: See Gems, Artificial.

STONEWARE: See Ceramics.

STONEWARE CEMENTS: See Adhesives and Lutes.

«STOPPERS.»

I.—To make an anti-leak and lubricating mixture for plug-cocks use 2 parts of tried suet and 1 part of beeswax melted together; stir thoroughly, strain, and cool.

II.—A mixture for making glass stoppers tight is made by melting together equal parts of glycerine and paraffine.

To Loosen a Glass Stopper.—I.—Make a mixture of

Alcohol 2 drachms Glycerine 1 drachm Sodium chloride 1 drachm

Let a portion of this stand in the space above the stopper for a few hours, when a slight tap will loosen the stopper.

II.—A circular adjustable clamp, to which is attached a strip of asbestos in which coils of platinum wire are imbedded, is obtained. By placing this on the neck of the bottle, and passing a current of electricity through the coils of wire, sufficient heat will be generated to expand the neck and liberate the stopper. Heat may also be generated by passing a yard of cord once around the bottle neck and, by taking one end of the cord in each hand, drawing it rapidly back and forth. Care should be taken that the contents of the bottle are not spilled on the hand or thrown into the face when the stopper does come out—or when the bottle breaks.

STOPPER LUBRICANTS: See Lubricants.

«STOVE POLISH:»

See also Polishes.

The following formula gives a liquid stove blacking:

Graphite, in fine powder 1 pound Lampblack 1 ounce Rosin 4 ounces Turpentine 1 gallon

The mixture must be well shaken when used, and must not be applied when there is a fire or light near on account of the inflammability of the vapor.

This form may be esteemed a convenience by some, but the rosin and turpentine will, of course, give rise to some disagreeable odor on first heating the stove, after the liquid is applied.