The history of error is quite unimportant, but it is curious to observe how exactly and accurately my grandfather (in "Zoonomia," Volume I., page 504, 1794) gives Lamarck's theory. I will quote one sentence. Speaking of birds' beaks, he says: "All which seem to have been gradually produced during many generations by the perpetual endeavour of the creatures to supply the want of food, and to have been delivered to their posterity with constant improvement of them for the purposes required." Lamarck published "Hist. Zoolog." in 1809. The "Zoonomia" was translated into many languages. LETTER 77. TO C. LYELL. Down, 28 [June 1859]. It is not worth while troubling you, but my conscience is uneasy at having forgotten to thank you for your "Etna" (77/1. "On the Structure of Lavas which have been consolidated on Steep Slopes, with remarks on the Mode of Origin of Mount Etna, and on the Theory of 'Craters of Elevation'" ("Phil. Trans. R. Soc." Volume CXLVIII., 1858, page 703).), which seems to me a magnificent contribution to volcanic geology, and I should think you might now rest on your oars in this department. As soon as ever I can get a copy of my book (77/2. "The Origin of Species," London, 1859.) ready, in some six weeks' or two months' time, it shall be sent you; and if you approve of it, even to a moderate extent, it will be the highest satisfaction which I shall ever receive for an amount of labour which no one will ever appreciate. LETTER 78. TO J.D. HOOKER. (78/1. The reference in the following letter is to the proofs of Hooker's "Australian Flora.") Down, 28 [July 1859]. The returned sheet is chiefly that which I received in MS. Parts seem to me (though perhaps it may be forgetfulness) much improved, and I retain my former impression that the whole discussion on the Australian flora is admirably good and original. I know you will understand and not object to my thus expressing my opinion (for one must form one) so presumptuously. I have no criticisms, except perhaps I should like you somewhere to say, when you refer to me, that you refer only to the notice in the "Linnean Journal;" not that, on my deliberate word of honour, I expect that you will think more favourably of the whole than of the suggestion in the "Journal." I am far more than satisfied at what you say of my work; yet it would be as well to avoid the appearance of your remarks being a criticism on my fuller work. I am very sorry to hear you are so hard-worked. I also get on very slowly, and have hardly as yet finished half my volume...I returned on last Tuesday from a week's hydropathy. Take warning by me, and do not work too hard. For God's sake, think of this. It is dreadfully uphill work with me getting my confounded volume finished. I wish you well through all your labours. Adios. LETTER 79. TO ASA GRAY. Down, November 29th [1859].