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NOTES ON EARTHQUAKES. 
BY REV. W. S. SYMONDS, RECTOR OF PENDOCK. 
I T was very generally believed, only a few years ago, that 
the earth was not more than about six thousand years 
old. Astronomers and geologists have, however, ascertained, 
beyond a doubt, that the planet we inhabit has not only been 
rolling in space for untold ages, but has undergone numerous 
physical changes. They also believed that this planet was 
once in a condition of complete fluidity, and almost up to the 
present time they considered the principal portion of the 
interior of the earth to be composed of mineral substances 
liquefied by intensity of heat. Of late, the labours of 
mathematical investigators have gone far to prove that the 
central nucleus of the earth is not altogether composed of 
molten mineral substances, so as to form a central igneous 
ocean, but that lakes or small seas of lava are distributed 
throughout her mass. Whatever truth there may be in this 
theory, it is to natural causes that we must look for the expla- 
nation of the phenomenon of the earthquake, that agent which 
has played so important a part in again and again remodelling 
the surface of the earth. 
From numerous observations made in deep mines, it is 
found that the temperature of the earth increases as we 
descend at the rate of 1° of Fahrenheit for every fifty or sixty 
feet after the first hundred. The phenomena of hot springs, 
and the emission of vast masses of molten mineral matter, 
volcanic ashes, mud, &c., from volcanos, with calculations 
founded on the known specific gravity of the earth, all tend to 
convince scientific men that the earth possesses a high internal 
temperature which is derived from internal sources. 
It is impossible to read the description given by Sir Charles 
Lyell of the phenomena of earthquakes and volcanos without 
being satisfied that both of these agents have, to a certain 
extent, a common origin ; but it is also certain that there are 
two modes of action in earthquake forces of disturbance — viz., 
when they act with local intensity, as in volcanic action, or by 
a succession of earthquakes, as in the elevation of the coast of 
