“Sir,—I am very much to blame for having so longdelayed an answer to the agreeable and interesting dispatchthat you have been kind enough to forward me, by thehands of Mr. Augustus Peterman, so estimable by his cha-racter, as well as by the solidity of his geographicallabours. Dr. Cullen cannot doubt the high importancethat I would attach to the merit of his courageous anduseful investigations in the eastern part of the Isthmusof Panama; knowing my position and my antedi-luvian age, be will receive with indulgence, evenso late, the expresson of my lively gratitude.After having laboured in vain, during half a century, toprove the possibility of an oceanic canal, and to point outthe Gulf of San Miguel and Cupica as the points mostworthy of attention; after having regretted, almost withbitterness, in the last edition of my ‘Aspects of Nature,’that the employment of the means which the present stateof our knowledge affords for obtaining precise measurementshas been so long delayed, I ought, more than any one else,to be satisfied to see, at last, my hopes for so noble an enter-prise revived. By your publications, sir, and by that ofMr. Gisborne, will be originated the great work ofchanging an important part of the commerce of nations,and of rendering more accessible the rich countriesof Eastern Asia and the Indian Archipelago. Theundertaking is by no means above the intellectual andmaterial power which civilised nations have attained to.The work should be one to last for ever; it should not com-mence with a canal with locks, like the magnificent Cale-donian Canal; it must be a really oceanic canal, withoutlocks—a free passage from sea to sea, across which thespeed of the navigation will be modified, but not inter-rupted, by the difference in height and non-coincidence ofthe tides.