Interior Condition of the Earth. — Le Conte. 39 
thick and the whole covered with water as before. Such a 
globe would behave exactly or almost exactly like a perfectly 
liquid globe. There would still be an earth-tide but no per- 
ceptible water-tide, i. e. no perceptible deepening of the water 
under the moon. The water-tide would be completely or 
nearly completely destroyed by the earth-tide. Suppose 4th, 
and finally, a perfectly solid and rigid earth covered with 
ocean. The tide, now, would be wholly a water-tide upon the 
unyielding earth, and would therefore be very perceptible. 
This is substantially the condition of things now on our globe. 
Now, physicists assert that if the earth were a liquid covered 
with a solid shell 50 miles or 100 miles, or even 500 miles 
thick, it would yield sufficiently to practically nullify the 
water-tide. I think therefore we must admit that the physicists 
are right and that the earth as a whole is rigid and therefore 
that it is a substantially solid globe. 
But, on the other hand, there are many geological phe- 
nomena which seem to demand an unlimited supply of liquid 
matter beneath a comparatively thin crust. Passing over vol- 
canoes which may be connected only with local reservoirs of 
liquid matter, the most important of these are the following : 
(1.) Great lavaAoods — such as that of the northwest, cover- 
ing at least 150,000 square miles 2000-3000 feet deep, and that of 
the Deccan plateau covering 200,000 square miles 6,000 feet deep. 
(2.) The formation of mountain ranges by lateral pressure. 
The concentration of the effects of lateral pressure along certain 
lines seems to require some slippage of the crust, on the deep- 
er parts ; but this would be impossible if the world were solid 
throughout. (3.) The oscillating movements of the crust 
over wide areas and especially subsidence under the weight of 
accumulating sediments and rising under the removal of 
weight by erosion. 
The house of Science seems then to be divided against itself. 
How shall it stand? Under the pressure of this' dilemma 
geologists have been more and more driven to accept a com- 
promise view ; or rather a view which combines and reconciles 
these two opposite and mutually excluding extremes, and 
therefore is more rational than either. According to this new 
\'iew the general constitution of the earth is that of a solid 
nucleus composing its great mass, a solid crust of inconsider^ 
able thickness, and a liquid or semi-liquid layer between. This 
