PAGE Volume of air required for drying rooms 191 room, Proportion of radiating surface to... 165 105 V seam, Bead or 262 W. Wages, Table of 365 Walls and windows, Diagram of heat loss through. 116 pipe, Definition of pipes, Fall for drain and.. stack, Definition of Waterback connections, Multiple range. 64 closets traps, Care of distribution in buildings 261 277 261 336 295 354 290 330 346 Water test of plumbing system Webster vacuum system of steam heating soil, waste, and vent pipe "cast-iron pipe 66 fireproofing materials. fireproof floors, Approximate 66 floors, partitions, and roofs.. 888888 87 86 66 galvanized iron piping 237 Troy zinc, copper, and lead "tin-lined lead pipe Weights and measures of cast-iron soil pipes. Table of "round galvanized-iron pipe, Table of. wrought-iron or steel drainage pipe, Table of 267 Wet return main, Definition of 264 238 308 41 145 161 271 87 116 262 262 262 263 358 262 262 pipe Woods, Table of weights and specific gravities of dry PAGE 350 122 90 273 43 350 Wrought-iron or steel drainage pipe, Table of weights of 267 pipe, Black 273 steam, gas, and water pipe, Dimensions of standard. 152 PLUMBERS AND FITTERS' HANDBOOK. ARITHMETIC. SIGNS USED IN CALCULATION. + Plus, indicates addition; thus, 10+5 is 15. Minus, indicates subtraction; thus, 10-5 is 5. X Multiplied by, indicates multiplication; thus, 10 X 5 is 50. Divided by, indicates division; thus, 10 ÷ 5 is 2. = · Equal to, indicates equality; thus, 12 in. - 1 ft. (), [], {}, called parenthesis, bracket, and brace, respectively, have the same meaning, and signify that the operations indicated within them are to be performed first; or, if more than one is used, that indicated in the inner one is to be effected first. Thus, in the expression 5(7-2), the subtraction is to be made before multiplying by 5. Again, in the subtraction indicated the expression [a+(b-;)]. 4 within the parenthesis is made first; the remainder is added to a, and one-half the sum found. -, called the vinculum, is used for the same purpose as the parenthesis, but chiefly in connection with the sign V; thus, V called the decimal point, is placed in a number containing decimals, to fix the value of the number; thus, 12.5 is 12 and 1.25 is 1 and; etc. X 8 = 82 means that the number 8 is to be squared; thus, 82 = 64. 8 1 83 means that the number 8 is to be cubed; thus, 83 called the radical sign, means that some root of the expression under it is to be found; if used without a small index figure, it means square root; thus, 64 8. mean that the cube or the fourth root is to be = 3. found, the index figure indicating the root; thus, 27 :::: means proportion; thus, 3:46:8 is read 3 is to 4 as 6 is to 8. Instead of the sign, the equality sign often substituted; thus, 3:4 = 6 : 8. = is 0 / 11 mean degrees, minutes, and seconds; as, 60° 15′ 15′′, which is read 60 degrees, 15 minutes, 15 seconds. 6 inches. also mean feet and inches; thus, 7' 6" is read 7 feet (read pi) means the ratio of the circumference of a circle to the diameter and 3.1416. = Σ (read sigma) means summation; thus, Σ(a + b) means that there are several values for both a and b, and that the sum of all is to be found. FRACTIONS. It is taken for granted that the reader knows how to perform the common operations of addition, subtraction, etc., where only whole numbers are used; but, when there are mixed or fractional numbers, a little refreshment of the memory may be desirable to some; hence, a little space is devoted to this elementary branch of arithmetic. COMMON FRACTIONS. The numerator of a fraction is the number above the bar; and the denominator is the number beneath it; thus, in the fraction 1, 3 is the numerator and 4 is the denominator. Two or more fractions having the same denominator are said to have a common denominator. By "reducing fractions to a common denominator" is meant finding such a denominator as will contain each of the given denominators without a |