INDEX. 549 



Page. 



Hodgins, Mr., notice by, of the meteorological system of Canada. 449 



Holland, meteorological system established in 45I 



Hoosac tunnel, observations in, on phenomena of sound 526 527 



Hour-glass form of thunder-cloud sometimes observed 361 



Howard, Mr. Luke, early classification of clouds by 247 



Human machine more efficient than the steam engine 127 



Human machine, like every other, requiring an engineer to direct it 128 

 Humboldt, Alexander, observations by, on elevated range of malaria 



in South America ifjg 



Humidity of soils diminishing their absorption of solar heat 193 



Hypothesis and theory distinguished 310 



Ice, artificial, the production of 203, 204 



Ice, cementation of, by re-gelation 201, 202 



Ice, melting, rapidly disintegrated by wind 198 



Ice possessing no more cohesive force than water 96 



Ice volatile at all temperatures 220 



Illness, personal, symptoms of, referred to 537 



Imagination required for scientific investigation 515 



" Imponderable " agents (so-called) subject to mechanical laws 314 



India, meteorological system established in 453 



Indian summer, the haziness of, possibly due to prairie smoke 257 



India-rubber, a great absorber of sound 415 



Induction from distant lightning observed 334 



Induction from electric spark, through several floors 333 



Induction of electricity illustrated 328 



Ingham, Hon. S. D., inquiries by, on the effect of telegraph lines 



on lightning 380 



Instruments for observing electrical absorption and induction 358, 359 



Insulation of lightning-rods quite unnecessary 401 



" Intensity " electro-magnet illustrated 429 



" Intensity " electro-magnet required to make the telegraph opera- 

 tive T. 427, 436 



Intensity of electrical discharge increased by cloud condensation 360 



Intensity of electric discharge increased with the length of the con- 

 Interference of waves illustrated 101 



International meteorological observations inaugurated in 1839 22 



Invention required for scientific investigation 515 



Isomeric compounds, illustrations of 114 



Isothermal lines in winter and summer, of the United States 71, 72 



Isothermal lines, irregularity of, due largely to ocean currents 62, 63 



Italy, meteorological system established in 451 



Joule, James P., atomic theory developed by 91 



Joule, James P., determination by of the mechanical equivalent of 



heat 136, 137 



