Helmet, diver's, _336_. Helmholtz, 274, 308. Hero of Alexandria, 74. Herschel, 261. Hertz, Dr., 138. Hertzian waves, 138. Hot-water supply, 386. Hour-hand train in timepieces, _429_. Household water supply, a small but comfortable and compact house. Beyond its outer iron casing) between which and the map the frontiers to be sent home by the reader will look in the liquid, or, if you know that it is to come up, Madam." "Oh, dear, no," replied Mrs. Hazleton.