paper will turn brown, in the presence of that gas. Blue litmus paper will turn red when exposed to carbonic acid gas, and the same gas will turn limewater cloudy when passed through. Simple Test for Drinking Water.-Organic Matter.-Into a perfectly clean bottle with a glass stopper, put 5 oz. of the water to be tested. Add 10 gr. of pure, granulated, white sugar. Cork tight, and set in a window exposed freely to light but not to direct rays of the sun. Do not disturb the bottle and keep the temperature as near 70° F. as possible. If the water contains organic matter, within 48 hr. an abundance of whitish specks will be seen floating about, and the more organic matter the more specks. In 1 wk. or 10 da., if the water is very bad, the odor of rancid butter will develop. Hard Water.-All the tests necessary for ordinary practical use can be made with articles which any druggist keeps in stock. A soap solution and a few glass vials, or test tubes, as they are called, are needed. To ascertain whether the water is hard or soft, take a clean tube, pour about 1 in. of soap solution into it, add a few drops of water, which if hard will turn it milky or curdy. Acidity. To ascertain if the water is acid or alkaline, fill the tube half full of water and dip a piece of red litmus paper into it. If the paper does not turn blue the water is not alkali. Next dip a piece of blue litmus paper in it, and if the paper does not turn red the water is not acid. Carbonic Acid.-To test for carbonic acid, pour into the tube about 1 in. of water and the same quantity of limewater. If there is carbonic acid, the water becomes milky, and on adding a little hydrochloric acid will become clear again. Sulphate of Lime.-To see if sulphate of lime (gypsum) is present, fill the test tube with about 14 in. of water, adding a little chloride of barium. If a white precipitate is formed, which will not dissolve when adding a little nitric acid, the water contains gypsum. Magnesia.-A test for magnesia is made as follows: Fill a test tube full of the water; bring it to a boil over a spirit lamp; then add a very little carbonate of ammonia, and the same amount of phosphate of soda; set it aside for some moments, and if magnesia is present it will form a white precipitate. Lead.-If the test tube is full of water, and 2 drops of cochineal are added, and the water turns blue instead of pink, it will denote the presence of lead. Copper.-Copper will be shown by adding a few drops of chloride of ammonium to some water in which has been placed a few filings of soft iron. If it turns blue, it is an evidence of copper. Iron.-Adding 1 drop of ferrocyanide of potassium to a little water in a test tube will color it blue if iron is present. A large number of tests are made in a thorough analysis, but these are the ones that principally interest the ordinary engineer, and can be made with the least trouble and expense. Analysts should be employed to make exact analysis of important supplies. To Clean Galvanized-Iron Pipe.-Galvanized-iron pipe can be cleaned and polished by scouring it with fine sand or powdered pumice and water. Polishing Lead Pipe.-Lead pipe can be cleaned and polished by scrubbing with powdered pumice and a wet cloth and then wiping dry and polishing with a dry cloth. To preserve the polish on galvanized-iron or lead pipes, they should be immediately covered with a thin coat of white shellac or white varnish applied with a brush. Care of Boilers in Summer.-It is considered the best practice to leave a heating system in the summer just as it has been running. Emptying the system induces rust, and if the local supply of water is hard, it induces deposits or boiler scale. Care of Water-Closet Traps.-It frequently is necessary in cold weather to leave a closet unused in a location that cannot be warmed. To prevent the water in the trap from freezing under such conditions put into the trap about 1 lb. of common salt. This amount of salt will saturate 3 pt. of water, which is approximately the volume required to fill a closet trap, and this solution will not be frozen at any temperature above zero. Or, remove the water and fill the traps with oil. This is also suitable for preventing loss of seal by evaporation in unoccupied houses. Freezing Service Pipes. It is sometimes necessary to freeze the water in service pipes to stop the flow while making repairs. This can be accomplished by temporarily stopping the flow of water with a wooden plug and packing the pipe in one of the following freezing mixtures: Lead and Oakum.-The amount of lead and oakum required to calk different sizes of joints of cast-iron pipe may be found in the following table: MATERIAL FOR CALKED JOINTS. Disinfectants.-Deodorizers are not necessarily disinfectants, and disinfectants do not necessarily have an odor. Water, air, and sunshine are the natural disinfectants. Whenever a sewer is stopped up and overflows, the place where the overflow occurs should be thoroughly disinfected. This can be accomplished by sprinkling the place well with a solution of copperas, and whitewashing all walls and exposed parts of the building with a wash made of freshly slaked quicklime. APPROXIMATE COST OF COMPLETE SYSTEMS. Plumbing. An approximate figure for cost of plumbing is 10 per cent. of the cost of the building. This figure is for good materials and labor, and of course is subject to considerable variation. For an ordinary house, costing from $1,500 to $3,000, the cost of plumbing may be taken as about 8 per cent. for moderate-priced fixtures and public-sewer service. The cost of labor alone will average about the cost of the materials. Gas-Fitting. The cost of gas-fitting may be approximately figured as about 3 per cent. of the cost of the building. The cost of labor alone varies from about to the cost of materials. The better the grade of fixtures, the lower will be the ratio-provided there is no excessive ornamentation, requiring much time to put in place-as the cost of the labor is about the same for cheap fixtures as for more costly ones. Heating. The cost of hot-air installation is, approximately, 5 per cent. of the cost of the building; for steam heating, 8 per cent.; for hot-water heating, 10 per cent. In estimating on heating by furnace, the average cost of labor is about that of materials. In steam and hot-water heating, the ratio is about 1. Caution. The actual cost of the plumbing, gas-fitting, or heating systems in a building will vary with the price of materials, the location of the building-whether in city or country-the condition of the trade, and many other considerations. The market prices of the materials used are fluctuating all the time. |