Show CONDITION OF THE EARTHS INTERIOR IN-TERIOR Latest Determination of the Scientists Scien-tists Are That the Globe Upon Which We Live is Solid to the Core and Its Density 5505 as Compared With Water Until very recent years the fact had hardly been questioned that by far the greater part of the earths interior was in the condition of a fluid or molten mass the volcanic manifestations exhibited ex-hibited on the surface the rapid rise of temperature that is found as we x proceed from the exterior to the interior in-terior and other considerations pointing point-ing almost irresistiblv to such a conclusion con-clusion Indeed a common belief was that all that was solid centered in a crust of some 50100 miles thickness floating on the fiery magma of the interior It is true that some physicists as Hopkins had reasoned out a probability proba-bility that this crust to withstand the strains that were imposed upon it could not have a thickness of much less than 500 or 1000 miles but his arguments had comparatively little effect fect toward dispelling the nations that had so long existed At the present time after the brilliant mathematical exposition of Sir William Thompson Lord Kelvin of Professor George Darwin of Professor Simon Newcomb and of Mr Rudski this doctrine of terrestrial fluidity is hardly longer taught A few there are who yet linger lin-ger with the old theory but the great mass of educators and their pupils except in regions where textbooks bear the impress of manufacture in the m < mal m-al power of a quarter of a century ago or morehave settled down to the comfortable conviction that our planet is as solid or rigidas a ball of glass or steelin fact twice as rigid according accord-ing to the determinations of M Rudski The doctrine of solidity does not how ever involve the assumption of equal but of average rigidity Again it is not implied that because the earth is virtuallv solid to the core local areas of liquidity or fluidity do not exist It I is upon these pockets or areas of 1 molten material theoretically assumed I to exist that the geologist largely relies t re-lies to harmonize his facts concerning earth movements etc with those of I the mathematical physic they are to I the entire mass of the earth what the I air snakes are to a block of ice s sum in the virtual solidity of the earth the interesting question suggests i sug-gests itself What Is the nature of the I rock masses that compose the interior An answer to this question is largely one of inference only We know the II rocks of the exterior and we know the rocks of the interior to a limited depth Can our knowledge of these rocks be made to answer the inquiry as to the nature of the rocks of the deep interior in-terior It Is perhaps too early to give reply to this inquiry but the interesting fact has long been known that the average density of the earth is nearly or quite double that of ordinary rock such as limestone sandstone or granite and it is assumed that its greatest density cannot easily be less than from five to ten times that of Its superficial materials mater-ials or 20 times the density of water This being so the rocks of the interior are either compressed to a prodigious degree to give them this weight or from they are of a different character those of the surface possibly containing contain-ing great quantities of metal In rela of the tion to this inquiry a knowledge exact density of the earth becomes of first importance and it is of special interest in-terest to note that an extended series of recalculations made by Richarz and KrigerMenzel extending back to the year 1SS4 and with final results recently re-cently announced to the Berlin academy acad-emy of sciences confirm within a very narrow marin the earlier results obtained ob-tained with less refined instruments by Cavendish and his successors through a period of upwards of 100 years these latest determinations fix the density of our planet at 5505 compared com-pared with water A HEILpRIN |