51G INDEX. 



Page. 



Hare, Dr. Robert, facilities for experiments afforded by 139 



Hare, Dr. Robert, theory by, of electrical action 303 



Harris, Dr. Snow, observations by, on screening influence of metals. 144 



Harvey, Mr., observations by, on color-blindness — — 236 



Hauy, theory by, of electrical action 301 



Hays, Dr., observations by, on color-blindness 237 



Heat, and a thermal telescope for distant radiation 283 



Heat, experiments on the radiation of 289 



Heat from the moon not satisfactorily determined 284 



Heat, interference of 254,283 



Heliostat, on a simple form of 192 



Helix of wire, vivid spark from 87 



Hereditary pre-disposition to color-blindness noticed 238 



Herschel, Sir John, observations by, of induction by magnetic rota- 

 tion 123 



Herschel, Sir William, theory by, of solar spots 224 



Hoosac tunnel, New York, observations at, on sound 499 



Horsford, Prof. E. N., remarks on paper b}' 288 



Hot-air engine employed with fog-trumpet 384, 385 



Human body a complex machine operated like other machines 312 



Human soul not properly a motor 312 



Humphreys, Gen'l Andrew A., facilities afforded by 392 



Hypotheses less useful as explanations, than as directing or suggest- 

 ing experiments 259 



Hypotheses when even erroneous may be useful 298, 300 



"Imponderables," on the theory of 297 



Induced currents and battery currents, difference in action of 128 



Induced currents from ordinary electrical discharge 105, 133 



Induction apparently propagated bj' undulations 302 



Induction at a distance of many feet 121, 139, 161, 203 



Induction coils with interposed plates 123 



Induction currents, alternation of successive orders of 159 



Induction currents, directions of, dependent on distance 137, 138, 143 



Induction currents, initial and terminal, similar 158 



Induction currents of third, fourth, and fifth orders 107, 127, 135 



Induction from increasing and from diminishing currents, opposite 



in sign 170 



Induction of current on itself, effects of 106, 131 



Induction of electrical cloud exerted at great distances 199, 251 



Inductive effects diminished by too great length of coil 116 



Inductive effects probable in thunder-storms 140 



Inertia not accounted for by the theory of Boscovich 256, 298 



Ingersoll, Gov. Charles R., co-operation of, in observations on 



sound 433 



" Intensity " and " quantity " currents from same induction 118 



" Intensity " and " quantity " of induced currents compared 113, 115 



