Sir

Would you be so good, if convenient, to return to me, by D^r J. Hooker, who will be at Berlin in a fortnight, the short sketch, which I sent you, of the facts regarding the Atlantic dust, & which I thought, perhaps, worth inserting in some English Journal: if you have examined the other specimens of dust, would you be so good as to inform me, that I might refer to your descriptions in this sketch.¹

Amongst the little packets, which I sent you, there were some of the earth of the Pampas, in which so many extinct mammifers are embedded, should you feel any interest on this subject, I should feel particularly thankful to hear the result of your examination. Should the subject not interest you, I should be sorry to think even of asking you to waste any of your time on it. There are, also, specimens of a singular white bed, (I now believe of a very fine tufaceous nature) which extends for hundreds of miles on the Patagonian coast, about which I am curious.

I beg to apologise for having thus troubled you, but might I further request you, should you see D^r. Dieffenbach, kindly to take the trouble to ask him, to return me my copper-plate, woodcuts, & M.S. corrections for his German edition of my Journal, which I cannot get him to return to me, though I shall be thus put to considerable loss of time & money, in preparing a second English Edition.—²

Believe me dear Sir | With great respect | Your’s faithfully & obliged | C. Darwin To | Professor C. Ehrenberg | &c &c &c