Connecticut western news., 1885-06-10
CAUSES OF EARTHQUAKES.
THE DIRECT CAUSE DECLARED TO BE
 R SUPERHEATED STEAM.
An Interesting Discourse Explaining How Earthquakes and Volcanic Eruptions are Caused.

Caused.
 It has been asked of late whether the hurricanes which followed the Spanish earthquakes were not produced by those subterranean disturbances, and all-ex- planning electricity has been called upon to explain how earth-throes might have caused atmospheric disturbances. I know of no way in which such con- sequences could have followed from a displacement of the earth's crust. To me it seems far more natural to conclude that the hurricanes aud earthquakes were alike produced (the hurricanes chiefly, the earthquakes partially by the atmospheric compression which pre- ceded the subterranean disturbances. This compression indicated heaping of air over the disturbed region; the earth's crust yielded under this increase of pressure, combined with the action of other forces, and earthquakes followed; the compressed air swept away to re- gions of less pressure, and the rare faction following led in the usual way to the indraught which precedes cycIonic disturbance in the air.
 But while the action of atmospheric pressure in helping to excite subter- ranean activities must not be overlooked, the varying pressure exerted by seas and oceans is a more potent disturbing factor. Atmospheric pressure Is dis tributed in such way that though the weight of air on any given area is con- tinually changing, there are no sharply defined lines, at any time, which separate regions of less pressure from regions of greater pressure. It is otherwise with the sea along a shore line. Here we have the sea acting with constantly varying intensity, as its level changes, on the seaward side of the shore line, while on the landward side there are no such variations of pressure.
 Let us consider what this means. Take tolersbly straight shore line 800 miles in length, and suppose that along this shore line a region of ocean 100 miles broad rises through 8 night of three feet under the combined action of sun and moon raising tidal wave, and favoring strong winds urging the water shoreward. Then we have 50,000 square miles of sea-water, three feet deep, added as so much dead-weight to that part of the earth's crust which underlies the seas along that shore. Each square mile contains in round numbers 8, ,00O,- 900 square yards, or 27, 900, 900 square feet. The additional weight corresponds, then Gas the added layer is three feet deep), 1000 times 81, 900, 900 cubic feet of water, each weighing 64s pounds, or to 116, ,OOO, ,OOO, 900 tons.
 isIt is clear that the addition of so enormous Q weight as this to the sub merged part of the earth's crust, outside the shore line, may well produce strains too great to be resisted. It must be remembered that the very existence of precipitous shore line (as distin- guished from one where the land above water and the parts submerged form one great slope) indicates the comparative weakness of the crust along that coast. It has yielded on one side to pressure thrusting it upward above the sea-level, and on the other side to the pressure of the water forcing it down. It is true, the actual line of yielding may not coincide with the existent shore line, for the action of the sea waves may (and generally musD have altered the position of the coast from that which is occupied when first formed. But it may be taken for granted that not far from every precipitous shore line lies line of weakness, where the crust has given away in the past, and may give way again. In this consideration undoubt. edly we find part of the explanation of the observed fact that almost all the great regions of subterranean activity or the earth lie near the sea-shore.
 But while the changes of the atmos- pheric and oceanic pressure are poten factors in the production of earthquakes and are probably in the great number O cases their direct occasion, it is, O
 course to the subterranean regions them
 selves that we must look for the forcei
 at work in upheaving the crust of tho
 earth. The forces acting from the out
 side are at the pull on the trigger; tn,
 imprisoned gases and vapors generated
 by internal heat are as the powder by
 whose explosion the missile is eiected.
 Yet even in considering the earth
 subterranean activities we still have t
 look outside for a part at least of tn
 causes of disturbance. The air ma.
 perhaps in this respect be neglected
 but the water is sll-important It ha
 been said indeed, and probably with
 nearer approach to truth than usual i
 the case of generalizations of the sort
 "Without water there can be no vol cano," and a similar rule (not quite s' generaD applies to earthquakes; few probably occur, possibly none, save : through the action of water in some wa or other. All active volcanoes except one Gin mid-Asia) are by the sea shore Nearly all the great earthquakes re  corded by history have taken place, an' have apparently had there center of dis
 turbance, near the sea.
 3 There can be very little doubt, indeed that the direct cause of every great sut F terranean disturbance is water in th , form of steam-steam superheated, ur ) der great pressure, and therefore po' 8 sessing much greater expansive powe s han steam at ordinary temperatures.- g Richard 4. Proctor in Harper's Mag . dzi7le.
 t THE Department of Agriculture is r' ? ceiving many requests for silkwormi [ eggs, and replies that they cannot | ? shipped successfully till fall
 ' THE penalty for eyen attemptinp