Sir—I am very much to blame for having so long delayedan answer to the agreeable and interesting despatch that youhave been kind enough to forward me, by the hands of Mr.Augustus Peterman, so estimable by his character, as wellas by the solidity of his geographical labours. Dr. Cullencannot doubt the high importance that I would attach tothe merit of his courageous and useful investigations in theeastern part of the Isthmus of Panama; knowing my posi-tion and my antediluvian age, he will receive with indul-gence, even so late, the expression of my lively gratitude.After having laboured in vain, during half a century, toprove the possibility of an oceanic canal, and topoint out the Gulf of San Miguel and Cupicaas the points most worthy of attention; after havingregretted, almost with bitterness, in the last edition of my“Aspects of Nature,” that the employment of the means,which the present state of our knowledge affords for ob-taining precise measurements has been so long delayed; Iought, more than any one else, to be satisfied to see, at last,my hopes for so noble an enterprise revived. By your pub-lications, sir, and by that of Mr. Gisborne, will be origi.nated origi-nated the great work of changing an important part of thecommerce of nations, and of rendering more accessible therich countries of Eastern Asia and the Indian Archipelago.The undertaking 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.—