Rensselaer Republican, Volume 16, Number 41, Rensselaer, Jasper County, 19 June 1884 — The Cause of Earthquakes and Volcanoes. [ARTICLE]

The Cause of Earthquakes and Volcanoes.

Earthquakes and volcanic eruptions are closely related to each other, like ice and snow. Each may be the effect of a different cause or both may result from the same cause, as there is evidently more than one cause at work to produce these effects. This statement will enable the general reader to form a tolerably clear idea of my meaning, and yet I am not satisfied with it myself. Therefore, I will vary it by saying that a chain of causes seem to combine, the different effects of which are earthquakes and volcanic eruptions. The most general cause of earthquakes is the tension and pressure of the crust, by which the oscillations and plications thereof have been produced. The tension and pressure have been caused by the shrinking and contracting of the crust, consequent upon its cooling. Plications are caused by a lateral or side pressure, in consequence of the contracting of the crust, whereby the strata, if of clay, loam, etc., are thrown into waves or ridges, giving an appearance something like a fluted column. I will give a familiar example of the forces that produce slight earthquakes, iff order that the young may have a clearer idea upon the subject. On building a fire in a stove, when the pipe begins to heat it will expand. At first there is a tension so slight that the iron of the pipe is able to resist it, but as the heat increases, the strain, or tension, overcomes the resistance suddenly, as a stick breaks when the strain is too great, and with a cracking sound. This is caused by expansion; but similar phenomena will result from contraction when the heat is subsiding. Thus it is with the earth’s crust. The straining, by either contraction or expansion, causes some place to yield with a loud report, instead of a “cracking,” as in the case of a stove pipe. If this event occurs near a volcano then an erupt ion ensues. Also, as there is a reflex action, terminating on the surface of the ocean of internal fire, an upheaval of the crust results, and if there is an ocean of water immediately above a tidal wave must be the consequence. Furthermore, should this slight shock of earthquake open a fissure in the crust, from a fountain of water being suddenly converted into steam, with not room enough in which to expand, other shocks will follow, attended by upheavels, earthquake wave and volcanic disturbances. These will continue for a shorter or longer period, and be slight or heavy, according to the amount of water precipitated, the size of the fissure and other conditions. Portland (Grogan) West Shore. % ■ . Dolls are now made that cry *and say papa and mamma, and now all that is really needed to make a childless home supremely happy is't® smear molasses candy over the carpets and furniture. — PhUadelphia Chronicle-Herald.