18461878] MISCELLANEOUS 219 



your noble problem, and I shall be very curious to have Letter 554 

 some talk with you and hear your ultimatum. 1 I do really 

 think, after Binney's pamphlet, 2 it will be worth your while 

 to array your facts and ideas against an aquatic origin of 

 the coal, though I do not know whether you object to fresh- 

 water. I am sure I have read somewhere of the cones of 

 Lepidodendron being found round the stump of a tree, or 

 am I confusing something else ? How interesting all rooted 

 better, it seems from what you say, than upright specimens 

 become. 



I wish Ehrenberg would undertake a microscopical hunt 

 for infusoria in the underclay and shales ; it might reveal 

 something. Would a comparison of the ashes of terrestrial 

 peat and coal give any clue ? 3 Peat ashes are good manure, 

 and coal ashes, except mechanically, I believe are of little 

 use. Does this indicate that the soluble salts have been 

 washed out ? i.e., if they are not present. I go up to 

 Geological Council to-day so farewell. 



In a letter to Sir Joseph Hooker, Oct. 6th, 1847, Mr. Darwin, in 

 referring to the origin of Coal, wrote :"...! sometimes think it could 

 not have been formed at all. Old Sir Anthony Carlisle once said to me 

 gravely that he supposed Megatherium and such cattle were just sent 

 down from heaven to see whether the earth would support them, and I 

 suppose the coal was rained down to puzzle mortals. You must work the 

 coal well in India." 



To J. D. Hooker. Letter 555 



Down May 22nd, 1860. 



Lyell tells me that Binney has published in Proceedings 

 of Manchester Society a paper trying to show that Coal 



The above paragraph was published in Life and Letters, I., p. 359. 



2 " On the Origin of Coal," Mem. Lit. Phil. Soc., Manchester 

 Vol. VIII., p. 148, 1848. 



3 In an article by M. F. Rigaud on " La Formation de la Houille," 

 published in the Revue Scientifique, Vol. II., p. 385, 1894, the author lays 

 stress on the absence of certain elements in the ash of coals, which ought 

 to be present, on the assumption that the carbon has been derived from 

 plant tissues. If coal consists of altered vegetable debris, we ought to 

 find a certain amount of alkalies and phosphoric acid in its ash. Had 

 such substances ever been present, it is difficult to understand how they 

 could all have been removed by the solvent action of water. (Rigaud's 

 views are given at greater length in an article on the " Structure and 

 Formation of Coal," Science Progress, Vol. II., pp. 355 and 431, 1895.) 



