Show UNDER THE EARTH many scientific men ari are devoti devoting nj their lives to finding out all that can be learned about the interior ol of this thi wonderful globe of 0 ours one of the interesting problems on 0 a which they are engaged is the depth and geographical limits 0 of permanently frozen froze t soil the british association has collected a large of data on this question they have already told us some curious things such as the fact that excellent wheat lands north of manitoba overlie frozen earth that never thaws sometimes geologists find strata of rocks that they are able to show must have been burled buried at a remote age 20 feet under the surface these upturned edges edgeson of rock which some terrible convulsion lifted to the air air gives us a glimpse of the conditi conditions of the interior some way below the greatest depth to which we can attain the workmen in the deepest mines of europe swelter in almost intolerable heat and yet they have never penetrated averone seven thousandth part of the distance from the surface to the centre of the earth in the lower levels of sonic some of the comstock mines the men fought scalding water and could labor only three or four hours at it a time until the sutro tunnel pierced the mines and drew off some soine of the terrible heat which had stood at 1200 the deepest boring ever made that at sperenberg erenberg Sp near berlin penetrates only feet about 1000 feet deeper than the famous utes artesian linwell well at st louis the result of this imperfect knowledge is i that there axe are more inore theories and disputes among scientific me n with regard to the interior of the earth khan han about any other problems of physical science some erni eminent nent physicists for instance like sit sir william thomson have at odwith boue thick thic fc the bia bority adduce good reasons for believing that thai the crust is only twenty five to fifty miles thick all agree that if the temperature pera ture within the earth continues td increase as it does near the surface at the rate of one degree to for r about every fifty five eva feet of descent all igneous rocks must be used fused at no creat depth in fact at this rate of Inc increase tease the temperature tit at miles is which is professor pr rossettie Ros Ross seltis ettis estimate of the probable temperature of 61 the sun it is improbable however that this rate of increase is maintained for a great distance and many physicists believe that at some unknown but not very great depth the increase in tern tem pera ture ceases one of the most wonderful things in the study of sciences is the fact that the mysteries ot of one science are sometimes times completely i or partly explained by knowledge cleaned in some other department of study it is thus that naturalists natura lists who have investigated the fauna and flora of scores of pacific islands have learned how far south asiatic types prevail pr evall and have added great weight to the conclusions clu of geologists that these islands were once a part of the big continent cont inert north of them 9 |