Your favor of the 6th. has been recieved, and I will beg leave to add a few supplementary observations on the subject of my former letter. I am not a judge of the best forms which may be given to the gunboat; and indeed I suppose they should be of various forms suited to the varied circumstances to which they would be applied. Among these no doubt Commodore Barney’s would find their place. While the largest & more expensive are fitted for moving from one seaport to another coast-wise, to aid in a particular emergency, those of smaller draught & expence suit shallower waters; and of these shallow & cheap forms must be those for Lynhaven river. Commodore Preble in his lifetime undertook to build such in the best manner for two or three thousand Dollars. Colo. Monroe, to whose knolege of the face of the country I had referred, approves, in a letter to me, of such a plan of defence as was suggested, adding to it a fort on the Middle grounds; but thinks the work too great to be executed during a war.1 Such a fort certainly could not be built during a war, in the face of an enemy. It’s practicability at any time has been doubted, and altho’ a good auxiliary, is not a necessary member of this scheme of defence. But the canal of retreat is really a small work of a few months execution; the laborers would be protected by the military guard on the spot, and many of these would assist in the execution for fatigue rations & pay. The exact magnitude of the work I would not affirm; nor do I think we should trust for it to Tatham’s survey: still less would I call in a Latrobe, who would immediately contemplate a canal of Languedoc.2 I would sooner trust such a man as Thomas Moore to take the level, measure the distances, and estimate the expence.3 And if the plan were well matured the ensuing winter, & laborers engaged at the proper season, it might be executed in time to mitigate the blockade of the next summer. On recurring to an actual survey of that part of the country, made in the beginning of the Revolutionary war under the orders of the Govr. & Council, by mr. Andrews4 I think, a copy of which I took with great care, instead of the half dozen miles I had conjectured in my former letter, the canal would seem to be of not half that length. I send you a copy of that part of the map, which may be useful to you on other occasions, & is more to be depended on for minutiae, probably, than any other existing. I have marked on that the conjectured rout of the canal, to wit, from the bridge on Linhaven river to Kemp’s landing on the Eastern branch. The exact draught of water into Linhaven river you have in the Navy office. I think it is over 4. feet.

When we consider the population & productions of the Chesapeak country, extending from the Genissee to the Saura towns5 and Albemarle sound, it’s safety & commerce seem entitled even to greater efforts, if greater could secure them. That a defence at the entrance of the bay can be made, mainly effective, that it will cost less in money, harrass the militia less, place the inhabitants on it’s interior waters freer from alarm and depredation, & render provisions and water more difficult to the enemy, is so possible as to render thoro’ enquiry certainly expendient. Some of the larger gunboats, or vessels better uniting swiftness with force, would also be necessary to scour the interior, & cut off any pickaroons which might venture up the bay or rivers. The loss on James river alone this year is estimated at 200,000 barrels of flour, now on hand, for which the half price is not to be expected. This then is a million of Dollars levied on a single water of the Chesapeake, & to be levied every year during the war. If a concentration of it’s defence at the entrance of the Chesapeak should be found inadequate, then we must of necessity submit to the expences of detailed defence, to the harrasment of the militia, the burnings of towns & houses, depredations of farms, and the hard trial of the spirit of the middle states, the most zealous supporters of the war, and therefore the peculiar objects of the vindictive efforts of the enemy. Those North of the Hudson need nothing, because treated by the enemy as neutrals. All their war is concentrated on the Delaware & Chesapeak; and these therefore stand in principal need of the shield of the Union. The Delaware can be defended more easily. But I should not think 100 gunboats (costing less than one frigate) an overproportioned allotment to the Chesapeak country, against the overproportioned hostilities pointed at it.

I am too sensible of the partial & defective state of my information to be over-confident, or pertinacious in the opinion I have formed. A thoro’ examination of the ground will settle it. We may suggest, perhaps it is a duty to do it. But you alone are qualified for decision by the whole view which you can command: and so confident am I, in the intentions as well as wisdom of the government that I shall always be satisfied that what is not done, either cannot, or ought not to be done. While I trust that no difficulties will dishearten us, I am anxious to lessen the trial as much as possible. Heaven preserve you under yours, & help you thro’ all it’s perplexities and perversities.