,326 



INDEX 



the equilibrium of three, 77 

 79 ; principle of, 76 ; resultant 

 of, 76, 77 ; the principle of 

 movements applied to, 79 81 



Parallelogram of forces, 64, 65 



Passage of an electric current, 

 198 205 ; of an electric current 

 through liquids, 199205 



Path of a ray of light through a 

 prism, 174, 175 



Period of rotation of the earth, 35 



Permanent, temporary and, hard- 

 ness of waters, 244, 245 



Phosphates, phosphoric acid and, 

 279, 280 



Phosphine or phosphoretted 

 hydrogen, 281, 282 



Phosphoretted hydrogen, phos- 

 phine or, 281, 282 



Phosphoric acid and phosphates, 

 279, 280 



Phosphorus, oxide, 280; and 

 hydrogen, compounds of, 280 

 282 ; and its compounds, 278 

 284 ; and oxygen, 279 ; general 

 characters of, 278, 279 ; manu- 

 facture of, 282 ; red, 279 



Physical, and chemical changes, 

 207, 208 ; change, solution is a, 

 209, 210 ; properties of sulphur, 

 248, 249 



Plane mirror, formation of an 

 image by a, 166 



Plastic sulphur, 249, 250 



Point, boiling, 151153 ; effect of 

 pressure on the, 152, 153 ; 

 marking the, 140, 141 ; freez- 

 ing, marking the, 139, 140 ; 

 melting, 151 



Polarisation, prevention of, 188 

 195 ; by chemical means, 191 

 195 ; by mechanical means, 188 

 190 



Poles, negative and positive, 193, 

 194; positive, negative and, 

 193, 194 



Porosity of matter, 3, 4 



Potassium chlorate, 223 ; chloride, 

 223 



Potential energy, 121. 122 



Precipitation, 212, 213 



Preparation and properties of 

 chlorine, 264267 ; of hydrogen, 



236239 ; of oxygen, 220222 ; 

 of salts, 299, 300 



Prepared, chemically, silica, 314 



Press, hydraulic, 13, 14 



Pressure, atmospheric, and Boyle's 

 Law, 106 117 ; liquids commu- 

 nicate, 12, 13 ; of a gas, rela- 

 tion between volume and, 112 

 1 14 ; of the atmosphere, 107, 108 ; 

 of the atmosphere at different 

 altitudes, 112; on the boiling 

 point, effect of, 152, 153 



Prevention of polarisation by 

 chemical means, 191 195 ; by 

 mechanical means, 188 190 



Principle, of Archimedes, and rela- 

 tive density, 91105 ; Archi- 

 medes's, applications of, 95 



Prism, analysis of light by a, 176 

 178 ; path of a ray of light 

 through a, 174, 175 ; refraction 

 through a, 173175 



Production of oxide of hydrogen, 

 238, 239 



Proof of formula C0 2 , 291 



Properties, of carbon dioxide, 290 ; 

 oxides and their, 222, 223 ; of 

 salt, 262264; of sulphur di- 

 oxide, 252 ; physical, and states 

 of matter, 1 20 ; physical, of 

 .sulphur, 248, 249 ; preparation 

 and, of chlorine, 264267 ; of 

 hydrogen, 236239 ; of oxygen, 

 220222 



Proportions of oxygen and hydro- 

 gen in water, 239, 240 



QUANTITATIVE character of chemi- 

 cal action, 223 225 ; composi- 

 tion of sulphuretted hydrogen, 

 258 ; nature of the, reactions, 

 302305 



Quantities of heat, measurement 

 of, 144, 145 



RADIANT heat and light, energy 



of, 125 

 Reactions, of hydroxides with 



acids, 301, 302 ; quantitative 



nature of the, 302305 

 Recomposition of white light, 179, 



180 

 Red phosphorus, 279 



