Do you not think a table (not rules) of conversion of French into English measures, and perhaps weights, would be exceedingly useful; also centigrade into Fahrenheit,--magnifying powers according to focal distances?--in fact you might make it the more useful publication of the age. I know what I should like best of all, namely, current meteorological remarks for each month, with statement of average course of winds and prediction of weather, in accordance with movements of barometer. People, I think, are always amused at knowing the extremes and means of temperature for corresponding times in other years.
I hope you will go on with it another year. With many thanks, my dear Jenyns,
Yours very truly, CHARLES DARWIN.
CHARLES DARWIN TO J.D. HOOKER. Down, Sunday [April 18th, 1847].
My dear Hooker,
I return with many thanks Watson's letter, which I have had copied. It is a capital one, and I am extremely obliged to you for obtaining me such valuable information. Surely he is rather in a hurry when he says intermediate varieties must almost be necessarily rare, otherwise they would be taken as the types of the species; for he overlooks numerical frequency as an element. Surely if A, B, C were three varieties, and if A were a good deal the commonest (therefore, also, first known), it would be taken as the type, without regarding whether B was quite intermediate or not, or whether it was rare or not. What capital essays W would write; but I suppose he has written a good deal in the 'Phytologist.' You ought to encourage him to publish on variation; it is a shame that such facts as those in his letter should remain unpublished. I must get you to introduce me to him; would he be a good and sociable man for Dropmore? (A much enjoyed expedition made from Oxford--when the British Association met there in 1847.) though if he comes, Forbes must not (and I think you talked of inviting Forbes), or we shall have a glorious battle. I should like to see sometime the war correspondence. Have you the 'Phytologist,' and could you sometime spare it? I would go through it quickly...I have read your last five numbers (Of the Botany of Hooker's 'Antarctic Voyage.'), and as usual have been much interested in several points, especially with your discussions on the beech and potato. I see you have introduced several sentences against us Transmutationists. I have also been looking through the latter volumes of the 'Annals of Natural History,' and have read two such soulless, pompous papers of --, quite worthy of the author...The contrast of the papers in the "Annals" with those in the "Annales" is rather humiliating; so many papers in the former, with short descriptions of species, without one word on their affinities, internal structure, range or habits. I am now reading --, and I have picked out some things which have interested me; but he strikes me as rather dullish, and with all his Materia Medica smells of the doctor's shop. I shall ever hate the name of the Materia Medica, since hearing Duncan's lectures at eight o'clock on a winter's morning--a whole, cold breakfastless hour on the properties of rhubarb!
I hope your journey will be very prosperous. Believe me, my dear Hooker,
Ever yours, C. DARWIN.
P.S.--I think I have only made one new acquaintance of late, that is R. Chambers; and I have just received a presentation copy of the sixth edition of the 'Vestiges.' Somehow I now feel perfectly convinced he is the author. He is in France, and has written to me thence.
CHARLES DARWIN TO J.D. HOOKER. Down [1847?].
...I am delighted to hear that Brongniart thought Sigillaria aquatic, and that Binney considers coal a sort of submarine peat. I would bet 5 to 1 that in twenty years this will be generally admitted (An unfulfilled prophecy.); and I do not care for whatever the botanical difficulties or impossibilities may be. If I could but persuade myself that Sigillaria and Co. had a good range of depth, i.e., could live from 5 to 100 fathoms under water, all difficulties of nearly all kinds would be removed (for the simple fact of muddy ordinary shallow sea implies proximity of land). [N.B.--I am chuckling to think how you are sneering all this time.] It is not much of a difficulty, there not being shells with the coal, considering how unfavourable deep mud is for most Mollusca, and that shells would probably decay from the humic acid, as seems to take place in peat and in the BLACK moulds (as Lyell tells me) of the Mississippi.