We have Been it stated that, for many weeks past, a series of experiments have been making, resulting in perfect success, of Grant's system of lighthouses, and a report in its favor is to be made to the next Congress by the naval officers by whom the experiments have been condncted. The plan is to make use of the Drummond light—the strongest artificial light known—which can be seen distinctly for many miles through a thick fog. The cost of the machinery will be about $1,000, whereas a “Fresnel” light costs $16,000. But the question arises, “can it be maintained as cheaply 1” We believe it cannot, and will await patiently for th'l next Report of the Lighthouse Board for positive inform""on.