H

Hammond, John Hays, 229.
Heaviside, A.W., 196.
Heliograph, 29.
Henry, Joseph, 65, 67, 158, 169.
Hertz and the Hertzian waves, 197.
Hubbard, Gardiner G., 149, 159, 170, 178.
Hubbard, Mabel, 148, 166.