To the People of New York
THE election for Charter officers last year was carried by the federal and quid trick of fortifications and now the people are to be amused and duped to a new obstruction.
The only eligible mode of obstruction is that proposed by Franklin for the Delaware in '76 an account of which was given in the Public Advertiser of the 8th inst and republished in the Philadelphia Aurora of the 13th August.
The plan of obstruction now proposed for New York is by blocks, that is, by solid bodies of stone or earth in the manner of wharves. This was first suggested by Selah Strong, Chairman of the Committee of the Corporation, and in a publication by Mr. Stevens of Hoboken, which contains many just observations on ships and batteries. He adopts the same unfortunate idea of obstruction by blocks. The blocks to be "25 or 30 feet square or larger at the distance of 50 or 60 feet from each other." And the editor of the New York American Citizen in introducing Mr. Smith's piece in his paper of Saturday last, says, "Why not, to make assurance doubly sure," to give us in fact protection, carry the obstruction by blocks or otherwise entirely cross from Robin's Reef to Mud Flat.
This most certainly would prevent hostile ships coming to the city, and it is equally as certain it would prevent the tide coming up and lay the wharves at New York dry, and be the ruin of all the towns on the North River that depend for commerce on tidewater, This, the projectors of obstructors by blocks never thought of; but projectors should think of everything or they will make ruinous work. If Selah Strong's project is adopted New York is ruined, for the obstruction by blocks cannot afterwards be removed.
Every alteration made in the channel of a water course, whether it be in the natural current of a river or the current of a tide, will cause another alteration some where else.
If the obstruction be across the natural current of a river like the obstruction of a mill dam, the water will continue rising till it overtops the obstruction or overflows the country above; for as the daily supply from the source will continue the same it will have a passage somewhere.
If the obstruction be to the tidewater, the effect will be, that the tidewater will rise to the same height at the place where the obstruction is as it did before and no higher, but the channel above the obstruction will be deprived of tidewater.
The stone piers of a bridge lessen the quantity and extent of tidewater above the bridge. This everybody knows that knows anything of hydraulics. But to know it as a fact, if any person will look into Salmon's geography or Guthrie's geographical grammar, he will find, in their account of rivers and bridges in England, that before Westminster bridge was built, which was begun in 1738 the tide flowed up to Kingston about 17 or 18 miles above Westminster, but since the bridge has been built it flows no higher than Richmond which-is four miles short of Kingston. Now, if the piers of a bridge lessened the quantity of tide-water, and shortened its extent four miles out of 17 or 18 miles, what must be the effect of a total, or even semi-total, obstruction by blocks of the channel between Robin's Reef and Mud Flat on the wharves at the city and on the long course of the North River?
In projecting obstructions two things are absolutely necessary to be taken into view. The one is, the least possible obstruction to the water up or down; the other is, that the obstruction be such as can be removed afterwards. Neither of these entered the mind of the projectors of blocks, and both are embraced in the plan of Franklin. His frames had very little effect on the tide or the stream; and after the enemy went away they were taken up; but all the power and art of Man could not remove solid blocks of stone or earth 25 or 30 feet square sunk several feet below the surface of the water.
If the channel between Robin's Reef and Mud Flat is not more than about 36 feet it can be obstructed as the Delaware was and the obstruction can be defended by gunboats and batteries, and the militia can defend the shore as the people of Norfolk have done; but for men to be always employing themselves on imaginary fortifications or skulking behind, or within obstruction like a turtle within his shell, lest the crows should pick him, has a very cowardly appearance. It is not the spirit of "the times that tried men's souls!'
Essay written in August 1807