Dr. Echo. Jaderin — On Variations of Climate. 437 



in a century would in a million years make nearly three degrees, 

 in ten million years nearly thirty degrees, etc., if taking place 

 uniformly with time. The cause of the great change in the climate 

 referred to, and the consequent entire revolution of flora and fauna, 

 must therefore, undoubtedly, with full justification be ascribed to the 

 shifting of the earth's axis, the more so as within the earth and 

 upon its surface transfer of matter is constantly going on, which 

 may again account for this shifting of the axis. These changes 

 again may be considered to be, in spite of the length of time, 

 periodical. 1 



There now remains the great question whether the change in the 

 climate is a continuous one in one direction throughout ages. Geo- 

 logists and astronomers are, as is generally known, almost agreed 

 upon the theory or hypothesis of the formation and development of 

 the earth, as well as other planets, from a chaotic mass in gas or 

 dust form to its present state. This theory demands that the earth 

 in its earliest stages as a planet should have possessed a very high 

 temperature, being in fact a red-hot ball, which gradually cooled 

 through a number of stages until reaching the present one. Accord- 

 ing to this, then, the earth should have cooled greatly since its first 

 state as a body, and the conditions upon it should consequently at 

 that period have differed greatly from the present, and that this was 

 so is fully verified by the discoveries from the most remote geological 

 epochs. The question is then : is this change of terrestrial con- 

 ditions still going on, or has it ceased? There is but little possibility 

 of answering this in the near future, but one thing is certain, we 

 must in our researches towards that end measure time by a gigantic 

 standard. 



However, it may be pointed out that there is this difference 

 between the early and present stage of the earth, that during the 

 former it was principally its own producer of heat, receiving most 

 of it from within. The atmosphere was enveloped in large masses 

 of vapour, and filled with heavy clouds, through which the sun's 

 rays never penetrated directly. The sun's heat had therefore little 

 effect, and would, even if it did penetrate to the surface of the earth, 

 have been of subordinate importance to that afforded by the earth 

 itself. Since that stage — the earth having cooled — the roles have 

 been reversed. The surface of the earth may now be considered as 

 receiving nearly all its heat from the sun. If there be still a glow- 

 ing interior, the heat shows itself only indirectly through volcanic 

 eruptions and hot springs. Should therefore the earth continue to 



1 See on this subject a most valuable and suggestive memoir " On a Possible 

 Cause of Olimatal Changes," by Dr. John Evans, F.R.S., F.S.A., Sec. Geol. Soc. 

 (1866) ; Proc. Royal Society, March loth ; also, Geol. Mag. 1866, Vol. III. 

 pp. 171-174, in which a change in the axis of rotation is advocated, not only as 

 best suited to explain the discoveries of an abundant animal- and plant-life in high 

 northern latitudes, demanding great climatal changes ; but also those changes due to 

 upheaval, depression, and denudation of the earth's surface which must affect the 

 earth's equilibrium. Also that astronomical observations tend to show " that the 

 ground itself shifts, with respect to the general earth, or that the axis of rotation 

 changes its position. 



