J. Wedgwood is returned, very little altered for the better. Coleridge is gone to reside in Cumberland; he was here the week before last, and spent much time with me, and often spoke of you with the greatest interest. Clayfield is at this moment chiefly engaged in commercial speculations. He has found a new mode of making soda, which there is every reason to believe will turn out profitable. I hope some time in the autumn to see you, and to enjoy the well remembered pleasure of your conversation; in the mean while, I remain, with respects to your family, Yours with sincere affection, HUMPHRY DAVY. [26] From his visit to London, as noticed at page 62. [27] With respect to the metaphysical speculation contained in this paragraph of his letter, had he not written it in haste, we might presume he would have given a more exact expression to his ideas. By the misapplied term "_Feeling of Procrastination_," he doubtless meant to describe that aversion to labour which becomes habit by indulgence, and the perception of which, so far from increasing in vividness, actually languishes to obtuseness. To borrow an expression from Dr. Johnson, Davy, in his metaphysical speculations, not unfrequently trod upon the brink of meaning, where light and darkness begin to mingle. [28] Davy here alludes to the fact of magnesian earth being prejudicial to vegetation. In estimating the early genius of Davy, and his character as a philosopher, the style and matter of his "RESEARCHES" will afford us much assistance. The close philosophical reasoning,--the patient and penetrating industry,--the candid submission to every intimation of experiment, and the accuracy of manipulation, so remarkably displayed throughout this work, have been rarely equalled, and perhaps never surpassed. There is scarcely to be found a more striking illustration of chemical genius, than that afforded by his chapter on the "Absorption of _Nitrous Gas by solutions of green Sulphate of Iron_." The address with which he gradually disentangles the subject of its difficulties, and catches at every opening to truth, affords a study which may be safely recommended to the attention of every young experimentalist, as being no less instructive than it is beautiful.