A Hand-Book of Formulae, Tables, and Memoranda for Architectural Surveyors, and Others Engaged in Building (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1876 Excerpt: ...there is seldom much danger of the water being used for domestic purposes. Dr. Clarke's Process of Softening Water. Bicarbonate of lime is the principal cause of hard-ness in water. This can be removed by adding s much lime in solution as there is of the bicarbonate in the water to be softened. The lime added combines with one-half of the car-bonic acid and becomes chalk, reducing the bicar-bonate already In the water to chalk also, which being insoluble settles at the bottom of the cistern-Hardness in water is measured, according to Dr. Clarke's scale, by the number of grains of chalk de-posited by the lime in a gallon (70,000 grains) of water, each grain is called a degree of hardness. Water of less than 5 degrees is considered soft, and over 12 degrees is considered hard. Wnter containing magnesium, sulphates, chloride?, und even lime in any other form than carbonate, is not affected by the process. It is estimated that 2i oz. of soap are required to soften every 100 gallons of water for each degree of hardness according to Or. Clarke's scale. Storage Of Water. Underground Tanks.--These are usually made of bricks or stone built in Portland cement or hydraulic lime mortar, and covered e-over with stone slabs or arches of masonry. The bottom should as a ale be formed with in-iarches, as sketch, Hurst's Handbook with or without a bed of concrete under, or with concrete alone, according to the nature of the ground. The sides and bottom of the tank should be ren-dered in Portland cement well trowelled, and if there is any danger of surface water penetrating the walls, they should be-backed in well-worked clay puddle, at least 12 inches thick, precaution being taken, if the tank is covered by an arch, to prevent the side walls, if thin, from bein...