Democratic Sentinel, Volume 11, Number 17, Rensselaer, Jasper County, 27 May 1887 — A Seismological Summary. [ARTICLE]

A Seismological Summary.

The vibrations of even severe earthquakes, says Prof. It. H. Darwin, are very short. Brick and stone cbinineys will be shattered by one of a quarter of an inch. Asa rule, the d sturbance originates from one and a half to seven m les below the surface, and very rarely at greater depths. Earthquakes occur on steeply sloping shores, and are most frequent in writer, when the changes in barometric pressure are greatest. The moon, also, probably has some influence. The weight of the air and of the tides act upon the situat on as a trigger upon a gun. 'I he internal heat of the earth is doubtless the moving cause, and the gradual uneven shrinkage of the surface its man festation. Mr. H. Carl, 139 Fourtli Street, Troy, N. Y., says: “My daughter had a sprained ankle; St. Jacobs Oil cured her in a .day or two. My son had rheumatism about nine years ago; St. Jacobs 01 cured him; lio has not been affected since. ” Price Fifty cents.