The engineer—Charles H. Haswell—of the Board of Underwriters in this city has presented an interesting report in reference to the condition of our harbor. In it he sets forth the danger to be apprehended of the channel growing so shallow that its navigation, at some future day, not very far distant, may be stopped, and our great commercial mart become desolate and forsaken by its thrifty merchants, and those who go down to the "great deep" in ships. It is complained that the vast amount of gravel, sand and filth, washed down from our dirty streets through the sewers, is one great cause of the evil ; these being deposited in the channel, thus tending to shoal it up. In the main ship channel 2,532,000 cubic feet of sand have been deposited in twenty years. Great quantities of mud are deposited from the water in our city docks; this is lifted by dredging machines, but the practice of removing it has simply been to carry it away on punts and dump it in the lower part of the channel, from whence it is brought back again by returning tides. This operation forcibly reminds us of the wisdom displayed by that Gothamite who employed the effectual method of destroying a hornet's nest in his barn by setting the building on fire. It is recommended as a remedial measure that the streets of the city be kept very clean, and that the dredged mud from the docks be removed in the punts, and be wheeled on shore to fill up low lands adjacent to the rivers or harbor. The remedial measures proposed must meet the approval of every person, without any reference to the probable shoaling up of the main ship's channel—an event which we think is very far distant.