554 INDEX. 



Paob. 

 Poisson, investigations by, as to the law of temperature due to ele- 

 vation ' ^., 49 



Polarization of light explained by transverse vibrations of the 



aether - 103 



Positive or vitreous electricity from glass, &c 317 



Potential matter different from exhausted matter 457 



Pouchet, observations by, on dust from the atmosphere , 257 



Pouillet, deductions by, regarding subterranean temperatures ___ 183 



Pouillet, hypothesis by, as to the origin of atmospheric electricity. 346, 347 



Pouillet, researches of, on solar radiation 149, 150 



Pouillet, researches of, on the temperature of space 147, 148 



Power as well as material supplied by the organic matter of the 



Power expended by the sun in building up plants, stored and given 



"Practical men" inefficient without the guidance of general 



Prussia, the earliest government to establish meteorological obser- 



" Quantity " electro-magnet illustrated — 430 



Quetelet, experiments by, on the total heat required by plants 186 



Quetelet, tables by, of the times of vegetative processes 188, 189 



Kadiant heat differently absorbed by different substances 191, 192 



Kain-belt moving across the equator with the sun 58 



Rain-fall in the eastern half of the United States chiefly derived 



from the Gulf of Mexico 289 



Rain-fall in the United States as affected by prevailing winds 287, 288 



Rain-fall less at elevations than on plains 259, 260 



Rain-fall, method of measuring 3, 259 



Rain-full observed at different heights 4,5 



Rain-gages, description and use of 1 



Rain-gage, most suitable size of 261 



Rain, the precipitation of, productive of a large amount of heat 226, 274 



Rain-water, various salts discovered in 166 



Range of lateral protection by lightning-rods 387 



Rape-seed or colza oil employed for light-house illumination 477 



Rarity of the air increased in geometrical ratio, with equally in- 

 creasing altitudes 47 



Reaumur, hypothesis by, of the definite amount of heat required 



for plant growth 185 



Redfiold, Prof., investigation of tornadoes by 292, 293, 306 



Reflection of sound observed within short distances 417 



Refraction of sound not observable at short distances 418, 419 



Refraction of sound resulting from the action of wind 522 



Regnault, determination by, of moisture of air at different temper- 

 atures 235 



