CONTENTS. Xi 



182. Vapor pressure of solutions of salts in water 181 



183. Pressure of saturated water vapor over ice, low temperatures .... 183 



184. " " " " *' " water, low temperatures . . 183 



185. " " " " " " " 0° to 374° C 183 



186. Weight in g per m^ of saturated water vapor 185 



187. Weight in grains per ft^ of saturated water vapor 185 



188. Pressure of aqueous vapor in atmosphere, various altitudes 185 



189. " " " " " " sea-level 186 



190. Relative humidity, arguments, vapor pressure and dry temperature . 187 



191. " " " wet and dry thermometers 189 



Thermometry 



192. Stem correction for thermometers, centigrade 190 



193. " " " " Jena glass, 0° to 360° C 190 



194. " " " " " " 0° " " " 191 



195. " " " " " " normal, 0° to 100° C . 191 



196. Gas and mercury thermometers, formulae 192 



197. Comparison of hydrogen and 16"' thermometers, 0° to 100° C . . . . 192 



198. " " " " 59"^ " 0° " 100° C. ... 192 



199. " *' " " 16™ and 59™ thermometers, -5° to 

 -35° C. . 192 



200. Comparison of air and 16™ thermometers, 0° to 300° C 193 



201. " " " " 59"^ " 100° to 200° C 193 



202. " " hydrogen and various mercury thermometers .... 194 



203. " " air and high temperature (59™) mercury thermometer 194 



204. " " H, toluol, alcohol, petrol ether, pentane thermometers 194 



205. Platinum resistance thermometry 195 



206. Thermodynamic scale; temperature of ice point, Kelvin scale .... 195 



207. Standard points for the calibration of thermometers 195 



208. Calibration of thermo-element, Pt—Pt-Rh 196 



209. " " " Cu-constantan 196 



210. Mechanical equivalent of heat, summary to 1900 (Ames) 197 



211. " " " " best value 197 



212. Conversion factors, work units 197 



213. EngUsh and American horse power, altitude and latitude variation . 197 



Melting and Boiling Points 



214. Melting points of the chemical elements 198 



215. Boihng points of the chemical elements 199 



216. Melting points, effect of pressure 200 



217. Freezing point of water, effect of pressure 200 



218. Boiling point, effect of pressure 200 



219. Inorganic compounds, melting and boiling points, densities 201 



