The Interior Of The Earth

The greategi depth oí tin: oarth lüthorto ittained by nnin's explorations has not reached more thim onu mile from the suriace. WUcn, ae Professor Forbesstati i, it is remembered " that the diameter of the earth is 7,900 miles," the. disproportion of our studies betwcen the surxacé and the interior of omt jilanet ia evident. We bave traversed eveiy sea from polo to [olo ; the desert, the prairie, the great tbrests and the inhtiid river founte havo ilike been cxplored. All the sci prove with waat ardor we havo studied things of the oarth's Burface and thence directcd duv iittciilion to distont pltuaetf to study tluiu ; yet pf our ovnn planoi u attempt hasbooij jaade belov pne (nilo down. What, however, we have lóar&od from descentis astoniehing. We have discovorcd that (lic earth ia not.a substance; 011 tin: oontrary, it has a fluid interior, and only the ernst is solid, umi rehitively aot so thick in proportíon as a hen's -, It is found tbat for erery hvmdrecl reet of desceni there is a rise ui' temperature of 2 degreos Fahronheit. Tliis is at the ráte of U! d,egrei '■' heit fpr eyory mile. Attweftty-fiyö miles deep wc aliould have a temperature of 3,000 degrofiis Fahrenheit, which is eieiit 1j nieh. iion, and the lava whioh we see ejectci liy yoleanocs. Now, without any verifyijag oxperiment, the existence of volcanoes in different parte of the world, the perpetual springa of boiling water in Ioelaad, and of wai m water inEngland, it Bath and Matlock, cleftrly prove the exiatpnoe ii' subterranean hoat. Fortunatelv, exn..niiieijts of a diff oharacter from íliose of desoending into the earth substantiate the fact of interior iluidity.