In the smaller dome is a twelve-inch equatorial telescope made by Alvan Clark & Sons, mounted at the Lick Observatory in October, 1881. There are also at Mount Hamilton, a six-and-one-half-inch equatorial telescope, a six-and-one-half-inch meridian circle, a four-inch transit and zenith telescope, a four-inch comet-seeker, a five-inch horizontal photoheliograph, the Crocker photographic telescope, and numerous clocks, spectroscopes, chronographs, meteorological instruments, and seismometers for measuring the time and intensity of earthquake shocks. The buildings and instruments at Mount Hamilton are imbedded in the solid rock, so as not to be affected by the high winds on the top of the mountain. In the _Century_ for March, 1894, Professor Holden gives an interesting account of earthquakes, and the instruments for measuring them at the Lick Observatory. In the Charleston earthquake of 1886, it is computed that 774,000 square miles trembled, besides a vast ocean area. The effects of the shock were noted from Florida to Vermont, and from the Carolinas to Ontario, Iowa, and Arkansas. The science of the measurement of earthquakes had its birth in Tokio, Japan, in which country there are, on an average, two earthquake shocks daily. "Every part of the upper crust of the earth is in a state of constant change," says Professor Holden. "These changes were first discovered by their effects on the position of astronomical instruments.... The earthquake of Iquique, a seaport town of South America, in 1877, was shown at the Imperial Observatory near St. Petersburg, an hour and fourteen minutes later, by its effects on the delicate levels of an astronomical instrument. I myself have watched the changes in a hill (100 feet above a frozen lake which was 700 feet distant) as the ice bent and buckled, and changed the pressure on the adjacent shore. The level would faithfully indicate every movement: ... "In Italy and in Japan microphones deeply buried in the earth make the earth tremors audible in the observatory telephones. During the years 1808-1888 there were 417 shocks recorded in San Francisco. The severest earthquake felt within the city of San Francisco was that of 1868. This shock threw down chimneys, broke glass along miles of streets, and put a whole population in terror." The Lick Observatory has a complete set of Professor Ewing's instruments for earthquake measurements. Accurate time signals are sent from the Observatory every day at noon, and are received at every railway station between San Francisco and Ogden, and many other cities. The instrumental equipment of the Observatory is declared to be unrivalled.