I have to finish this Lindheimer collection, finish Fendler’s, distribute and study Wright’s collection when I get it, carry the “Botanical Text-Book” through the press, rewriting and expanding it (thus far I have made it all over), write the first volume of an elaborate report on the Trees of United States for the Smithsonian Institution, in fact a Sylva, with colored plates by Sprague (which I could not resist taking in hand, as that institution promised to bring it out, and handsomely, at their expense), and give my course of lectures in the college from March to June. When all this is done I can cross the Atlantic.... By engaging a brother professor to take the duties which I have for the autumn term (assigning to him pro rata from my salary), I shall be free until 1st March ensuing. But I mean to ask for leave of absence for a year, and trust I shall get it.... As far as it has yet shaped itself my plan is ... to sit down hard to work for the autumn and winter on the Exploring Expedition plants, to go to Paris in the spring and settle such questions as must be settled there after I come to know better than I now do (except in the Compositæ) what they are. Excepting the Oregon and Californian plants, which are assigned to Torrey, and the Sandwich Islands Collection, a fine one, the collection is a poor one, often very meagre in specimens, too much of an alongshore and roadside collection to be of great interest. I am not familiar with tropical forms and have no great love for them. I dislike to take the time to study out laboriously and guessingly, with incomplete specimens, and no great herbaria and libraries to refer to, these things which are mostly well known to botanists, though not to me, and I want to be taken off from North American botany for as short a time as possible. I must therefore come abroad with them, which the pay that is offered will enable me to do. I have found a good deal to interest me in the Compositæ, especially those of Rio Negro, of north Patagonia and of the Andes of Peru.... Now, will you take it as a bore, an imposition on your kindness, if I frankly ask whether I can possibly offer you any sort of inducement to aid me, at least so far as to run over the collections with me, and name those that are familiar to you as we pass, and refer others, as nearly as one can without study, to their proper places? Your mere comments in running through would save half my time. It is most natural that you should not incline to any such trouble, and I know your hands are always full; so, if you say no, I shall feel it is quite right, and do the best I can.... We shall be most glad to visit you at Pontrilas house at whatever time best suits Mrs. Bentham and yourself, whether in summer or in autumn, any time before we settle down into our winter quarters.... With best wishes to Mrs. B. and yourself for the new year, I am very faithfully yours, A. GRAY. TO W. J. HOOKER. April 2, 1850.