I agree that if Scott's red cowslip grew wild or spread itself and did not vary [into] common cowslip (and we have absolutely no proof of primrose or cowslip varying into each other), and as it will not cross with the cowslip, it would be a perfectly good species. The power of remaining for a good long period constant I look at as the essence of a species, combined with an appreciable amount of difference; and no one can say there is not this amount of difference between primrose and oxlip. (PLATE: HUGH FALCONER, 1844. From a photograph by Hill & Adamson.) LETTER 180. HUGH FALCONER TO W. SHARPEY. (180/1. Falconer had proposed Darwin for the Copley Medal of the Royal Society (which was awarded to him in 1864), but being detained abroad, he gave his reasons for supporting Darwin for this honour in a letter to Sharpey, the Secretary of the Royal Society. A copy of the letter here printed seems to have been given to Erasmus Darwin, and by him shown to his brother Charles.) Montauban, October 25th, 1864. Busk and myself have made every effort to be back in London by the 27th inst., but we have been persecuted by mishaps--through the breakdown of trains, diligences, etc., so that we have been sadly put out in our reckoning--and have lost some of the main objects that brought us round by this part of France--none of which were idle or unimportant. Busk started yesterday for Paris from Bruniquel, to make sure of being present at the meeting of the Royal Council on Thursday. He will tell you that there were strong reasons for me remaining behind him. But as I seconded the proposal of Mr. Darwin for the Copley Medal, in default of my presence at the first meeting, I beg that you will express my great regrets to the President and Council at not being there, and that I am very reluctantly detained. I shall certainly be in London (D.V.) by the second meeting on the 3rd proximo. Meanwhile I solicit the favour of being heard, through you, respecting the grounds upon which I seconded Mr. Darwin's nomination for the Copley Medal. Referring to the classified list which I drew up of Mr. Darwin's scientific labours, ranging through the wide field of (1) Geology, (2) Physical Geography, (3) Zoology, (4) physiological Botany, (5) genetic Biology, and to the power with which he has investigated whatever subject he has taken up,--Nullum quod tetigit non ornavit,--I am of opinion that Mr. Darwin is not only one of the most eminent naturalists of his day, but that hereafter he will be regarded as one of the great naturalists of all countries and of all time. His early work on the structure and distribution of coral reefs constitutes an era in the investigation of the subject. As a monographic labour, it may be compared with Dr. Wells' "Essay upon Dew," as original, exhaustive, and complete--containing the closest observation with large and important generalisations.