Mr. Duer, pursuant to a resolution of this morning, reported certain alterations he had made in the draft of a letter to the Honble. the President of the Continental Congress, agreed to on the 28th inst. which were approved of, and by which the following was substituted instead of that part of said letter contained between the words "defenceless parts of New-Jersey, in conclusion of the first paragraph, and the words "however severe the sudden reverse of fortune," in beginning of the last paragraph, vizt:

In perfecting the obstruction between Anthony's Nose on the eastern shore and Fort Montgomery, we endeavoured to avail ourselves of the model of that which had proved effectual in the river Delaware, and were assisted by the advice and experience of Capt. [John] Hazelwood, but the great length of the chain, being upwards of 1800 feet, the bulk of the logs which were necessary to support it, the immense weight of water which is accumulated, and the rapidity of the tide, have baffled all our efforts; it separated twice after holding only a few hours.

Mr. Mechin, the engineer at Fort Montgomery, is of opinion that with proper alterations it may still be of service in another part of the river, and we have, with General Heath's concurrence, directed him to make the trial. But we have too much reason to despair of its ever fully answering the important purpose for which it was constructed. A like disappointment, we are informed, happened at Portsmouth, the chain intended to obstruct the navigation of that harbour, proving equally ineffectual. These considerations have induced us to explore the depth of the river throughout the Highlands, in which a committee of the Convention have been assisted by Gen. George Clinton. The distance and depth of water at the north entrance, which, on the experiment, is found to be the fittest place, will be seen by the enclosed plan. General Heath, on a conference with General Clinton, has been pleased to recummend the obstruction of the navigation in this part of the river by cassoons, and the Committee of Safety, after mature deliberation, conceiving it to be very practicable, have agreed to the further resolutions, which are herewith transmitted, They wish on account of General Washington's distance and the multiplicity of business with which he is encumbered, that the direction of this work may be committed to Major General Schuyler, who we believe to be every way qualified to ensure its success. Timber and stones can be co~veniently procured, and when the campaign terminates, the troops cantoned in this part of the country may be employed in rotation to assist in the work. If the enemy persevere in their plan of subjugating the States to the yoke of Great Britain, they must, in proportion to their knowledge of the country, be more and more convinced of the necessity of their becoming masters of Hudson's river, which will give them the entire command of the water communication with the Indian nations, effectually prevent all intercourse between the eastern and southern confederates, divide our strength and enfeeble every effort for our common preservation and security. That this was their original plan, and that General Carlton and Genl. Howe flattered themselves with the delusive hopes of uniting their forces at Albany, every intelligence confirms; and it appears to the committee that they will not give up this grand object until they shall finally relinquish the project of enslaving America.

The committee take the liberty to submit these reflections to the Honourable Congress. If they are well founded, an early and vigorous preparation to oppose the progress of the enemy in this quarter must be indispensable, and the defence and security of Hudson's river a principal object of that preparation.

Ordered, That a copy of the said letter, as amended, be engrossed and signed by the President and transmitted.