1.0000 Iron, Of Capacities of Bodies for Heat referred to Water as the Standard. Water,. Olive oil, Linseed oil, •1300 Oil of turpentine, 4720 Soft bar iron, •1190 Ice, Chalk, Sea salt, The pressure or gravity of the atmosphere, being equal to a column of water 34 feet in height, is the means or principle on which rests the utility of the common pump, also of the syphon, and all other such hydraulic applications. In the pump, the internal pressure on the surface of the liquid is removed by the action of the bucket; and as by degrees the density becomes lessened, so the water rises by the external pressure to the above-named height; and at such height it will remain, unless by some derangement of construction taking place, the atmospheric fluid is allowed to enter and displace the liquid column. But observe, if the temperature of the water or other liquid be so elevated that steam or vapor arise through it, then, according to the vapor's accumulation of density, may the action of the pump be partially or wholly destroyed; and the only means of evasion in such cases is to place the working bucket beneath the surface of the liquid which is required to be raised. TABLE Of the Degrees of the three Thermometrical Scales, 392 200 160 356 180 144 320 160 128 284 140 112 248 120 96 383 195 156 347 175 140 311 155 124 275 135 108 239 115 92 374 190 152 338 170 136 302 150 120 266 130 104 230 110 88 365 185 148 329 165 132 293 145 116 257 125 100 221 105 84 To convert the Degrees in the three Scales into each other. To convert Centigrade or Reaumur's into Fahrenheit's Degrees.-Multiply the number of degrees by 9, divide the product by 5 for Centigrade, or by 4 for Reaumur's; add 32 to the quotient, and the sum will be degrees of Fahrenheit. To convert Fahrenheit's into Centigrade or Reaumur's Degrees.-Subtract 32 from the number of degrees, and divide the remainder by 9; multiply the quotient by 5 for Centigrade, or 4 for Reaumur's; the products will be the required degrees respectively. Comparative Table of the Degrees of the three Thermometrical Scales. Fahr't Cent. Rea. Fahr't Cent. Rea. Fahr't Cent. Rea. Fahr't Cent. Rea. Fahr't Cent. Rea. TABLE of the Weight of Substances of Construction, showing the weight of a cubic inch, and a cubic foot, in ounces and pounds avoirdupois, and also the number of cubic inches in one pound, of the substances most used in construction. Conducting Power of Materials used in the Construction of Houses. Air and gases are very imperfect conductors. Heat appears to be propagated through them almost entirely by conveyance, the heated portions of air becoming lighter, and diffusing the heat through the mass in their ascent as in liquids. Hence, in heating a room with hot air, the hot air should be introduced at the lowest part. The advantage of double windows for warmth depends, in a great measure, on the sheet of air confined between them through which heat is very slowly transmitted. Capacity of Bodies for Transmitting Heat. The capacity which bodies possess of transmitting heat, does not depend upon their transparency; or bodies are not all transparent to heat in the same proportion that they are transparent to light. The following plates of an equal thickness of 1031 inches allowed very different proportions of heat to pass through them. Of 100 rays transmitted from an Argand oil lamp there were: Rock salt,. Mirror glass, 92 | Emerald, 29 Rock crystal,. 62 Fluor spar, 15 Iceland spar,. 62 Citric acid, 15 Rock crystal, smoky & brown 57 Carbonate of lead, 52 Alum, 12 Sulphate of barytes, 33 Sulphate of copper, 0 SOLDERS. For Lead-Melt one part of block tin, and, when in a state of fusion, add 2 parts of lead. Resin should be used with this solder. For Tin.-Pewter, 4 parts; tin, 1; bismuth, 1. Melt them together and run them into slips. Resin is also used with this solder. For Gold-Pure gold, 12 parts; silver, 2; copper, 4. For Brass.-Brass, 2 parts; zinc, 1. For Iron-Good tough brass, with a small quantity of borax. For Pewter.-Bismuth, 2 parts; lead, 1; tin, 2. For Copper.-Copper, 2 parts; zinc, 1. For Silver.-Silver, 5 parts; brass, 6; zinc, 2. Soft Solder.-Tin, 2 parts; lead, 1 part. |