312 A. Vaughan — Critique on Results of a ShrinJdng Globe 



action. I would suggest that in all probability, even if these 

 materials did sink into the ground, its loose constitution would 

 prevent the formation of any deposit as rich as Black Earth. 

 Owing to the matting of the roots above-mentioned, it is always 

 necessary to remove the upper layer of black soil round any spot 

 where trees are to be planted. Mr. Christy has maintained that trees 

 on the treeless plains grow readily. Mr. Eodway admits this to be 

 true in part. For Russia, I may venture to go further, and say that 

 Black Earth is in many respects absolutely inimical to the growth 

 of wood or forest. 



, (To be continued in our next Number.) 



VII. — Remakks on Mk. Mellard Ebade's Article " On the 

 Eesults of Unstmmetrioal Cooling and Redistribution of 

 Temperature in a Shrinking Globe as applied to the Origin 

 OF Mountain Ranges." 



By A. Vaughan, B.A., B.Sc. 

 {^Addendum to paper on Corrugations of Earth's Surface.'] 



AFTER I had written the above dissertation and sent it for 

 publication my attention was kindly drawn to a paper, dealing 

 with the same subject, communicated by Mr. T. Mellard Reade, C.E., 

 F.G-.S., to the Liverpool Physical Society, and since republished in 

 the May number of the Geol. Mag. for this year (p. 203). 



As I was not aware, when engaged upon my own paper, of the 

 views which Mr. Reade had expressed, I feel that some discussion 

 of the theory put forward by that writer is of necessity demanded. 

 Since, however, Mr. Reade's views are extremely antagonistic to 

 those which I have already endeavoured to explain, such discussion 

 will find its most convenient place as a brief addendum to what I 

 have already written. 



Mr. Reade's paper opens with a statement of some results arrived 

 at by Lord Kelvin in his classical paper on the " Cooling of the 

 Earth"; since the utmost importance is necessarily attached to 

 the conclusions arrived at by' so eminent a physicist, it is very 

 important that such results should be quoted correctly, and also 

 that their statement should be accompanied by a short exposition 

 of the assumptions on which they are based. I propose then, in 

 the first place, to point out, as plainly and briefly as possible, 

 the method of reasoning employed and the data assumed in Lord 

 Kelvin's essay ; this I regard as especially necessary, because Mr. 

 Reade not only mis-states some of the most important results, but 

 also invests them with a rigidity to which the writer expressly 

 lays no claim. 



The essence of the employment of Fourier's equations depends 

 upon assuming that we are dealing with nothing but the conduction 

 of heat from point to point. Thus, no heat must be supposed to be 

 used up or evolved in changing the physical state of the material 

 under consideration ; for example, we cannot suppose that any 

 large portion of the mass has, during the time we are considering, 



