A communication from J. J. Murdock, has been submitted to the Common Council, sug gesting a new plan by which the city can be supplied with water. He says that the south ern slope of the island rests upon a clean bed ot sand and coarse gravel, which is filled with pure and fresh water, and he proposes to ex cavate a large basin, into which a sufficient quantity of water will collect, to supply 50 gallons for each of 500,000 inhabitants.— The basin to be ot such ex-tent of periphery, that the water flowing into it will not bring with it the sand, and of such depth that the sand shall not be forced up from the bottom. From near the centre of this reservoir—which is to beat a distance of five miles from the city boundary—he proposes to take the water at or near the surface through iron pipes, and conduct it to a pump placed at a suitable dis tance from the basin by which it would be forced into a stand pipe about 2,000 feet above tide-water, and thence be conducted through mains to a distributing reservoir on Prospect Hill. From this point its distribution would be the same as the one now proposed. The communication was referred to the Water Committee.