It is usually of a dark blue or greenish gray color and has the property of setting or hardening under water. It is also the strongest cement developing a strength of 550 to 650 pounds per square inch in one month. NATURAL CEMENTS are made by calcining and subsequent grinding of limestone or magnesian limestone containing from 20 per cent to 40 per cent clay. Natural cements are lower in strength than Portland cements but for many uses are fully as serviceable and usually cost less. Develop a strength of 200 to 300 pounds per square inch in one month. POZZUOLANA CEMENT is a material resulting from mixing and grinding together an intimate mixture of slacked lime and a Pozzuolanic substance such as blast furnace slag or volcanic scoria. MIXED CEMENTS are made by blending together in various proportions the types of cements named above. Concrete (Jones Laughlin Steel Co., Pittsburgh, Pa.) Concrete is a combination of sand and stone or other material with cement which binds it together. To obtain a strong durable concrete, it is essential that the sandstone or other material be clean and strong and that the best cement be used. Varying proportions of sand and stone can be mixed with one part of cement, according to the class of work. A common mixture is as follows: Cement, 1 part; sand, 2 parts; gravel or crushed stone, 4 parts. To obtain satisfactory results in the use of concrete it is absolutely essential that the formulæ be strictly followed, material accurately measured and the following rules observed: Use clean materials only. Do not guess as to measurements. Do not use less than the formula calls for. Mix thoroughly-and a little more. Put your concrete in place at once. Ram the concrete well into place. Keep concrete thoroughly wet during setting process. Protect concrete, after placing, from wind, sun and freezing. For Floors (Added). The crushed rock should be clean and run 3/4 or 1 inch in size. Use 1 part Portland cement, 2 parts clean, sharp sand or screened gravel, 4 parts of crushed rock. This is known as a 1 to 6 mixture. (1 cement, 6 mixture.) The above mixture is used for bottom course in floors. The topping should be 1⁄2 to 3/4 inch thick and will be made as follows: 1 cubic foot, or 1 sack, Portland cement mixed thoroughly with 11⁄2 cubic feet regular top sand or gravel. In drying out the work where there is too much water on the surface use a mixture of 1⁄2 sand and 1⁄2 cement dusted on dry before floating (smoothing is known as floating). Brick Work (Jones Laughlin Steel Co., Pittsburgh, Pa.) To find the number of bricks in a cubic foot of masonry. 1. Add to the face dimensions of the kind of bricks used, one-half the thickness of the mortar or cement in which they are laid and compute the area. 2. Multiply this area by the quotient of the thickness of the wall divided by the number of bricks of which it is composed; the product will be the volume of a brick and its mortar in cubic inches. 3. Divide 1,728 by this volume, and the quotient will be the number of bricks in a cubic foot. Corners are not measured twice as in stone work. Openings over two feet in size are deducted. Arches are counted from the spring. Fancy work counted 11⁄2 bricks for 1. Pillars are measured on their face only. A cubic yard of mortar requires 1 cubic yard of sand and 9 bushels of lime and will fill 30 hods. 1,000 bricks, closely stacked occupy about 56 cubic feet. 1,000 old bricks, cleaned and loosely stacked occupy about 72 cubic feet. Stock bricks commonly measure 834 inches by 44 inches times 234 inches and weigh from 5 to 6 pounds each. (Varies in different locations.) Paving brick should measure about 9 X 42 X 134 inches and weigh about 41⁄2 pounds each. Wire Ropings Lubricant 1. Tar 100 parts; brewer's pitch, 100 parts; colophony, wt. parts; train oil, 1 p. parts. Melt together and stir until the mass is cold. 2. For the lubrication of wire ropes use a mixture of mica, axle grease, tar and summer oil. Can be made of any desired consistency. The tar and oil must be free from acid. It is claimed that it thoroughly penetrates between the wires, prevents rust and fills the cable, resists water, does not strip and is very economical if added sparingly, as all lubricants should be, after the first dose. Cables well taken care of will last much longer than if neglected. Chain Lubrication A mixture of powdered plumbago and glycerine is recommended. Plumbago 6 parts mixed intimately with 10 parts of petroleum also makes a satisfactory lubricant. Tinplate The trade term "Base Box" means 112 sheets of tinplate 14 X 20 inches in size, or its equivalent. A base box contains 31,360 square inches or 217.777 square feet. Plates are made in the following weights, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 107, 128, 135, 155, 175, 195, 235. Also in 140, 180, 210, 240 and 270 pounds per base box. The number of base boxes of tinplate required to manufacture 1,000 cans of the various sizes is as follows: The number of base boxes required will vary somewhat in different plants owing to the original size of tinplate used and the consequent waste in manufacture. The difference however, will not be very great. The cans per carload will depend on whether the car is 36, 40, 45 or 50 feet in length. Acknowledgment Acknowledging credit to the following persons and publications for information furnished. Anderson, Barngrover Mfg. Co., San Jose, California. Canners' League of California, San Francisco. National Canners' Association, Washington, D. C. University of California, Department of Agriculture. A. W. Bitting, formerly National Canners' Assn. W. D. Bigelow, National Canners' Association. W. V. Cruess, Dept. of Agriculture, University of California. California State Board of Health. California Peach Growers', Association, San Francisco, Calif. California Prune and Apricot Growers' Association, San Jose, Calif. California Pear Growers' Association, San Francisco, Calif. Sun-Maid Raisin Growers, Fresno, Calif. Western Sugar Refining Co., San Francisco, Calif. Fireman's Fund Insurance Company, Marine Insurance, San Francisco Jones Laughlin Steel Co., Pittsburgh, Pa. Dallas H. Gray, Farm Accountant, Fresno, Calif. Southern Pacific Railroad Company. Howard C. Rowley, California Fruit News, San Francisco, Calif. Geo. C. Roeding, California Nurseries, San Francisco, Calif. Chicago Canner, Chicago, Ill. The Canning Trade, Baltimore, Md. The Canning Age, Seattle, Wash. Traffic Publishing Co., Traffic Red Book, New York City. |