"The mean weight of deposits is thus found to be 2.633 grains in every 30 cubic inches of water examined; (42.131 divided by 16 equal to 2 633.) Excluding therefrom all the city localities, except one upon each side of it, for the purpose of arriving at a mean of the average presence of silt in the water of our harbor above the Narrows, the following result is obtained: "From which it appears that the average annual flow of silt in the rivers bordering this city reaches the enormous rate of 1.209 grains in every 30 cubic inches of water (9.676 divided by 8 equal to 1.209 ;) and assuming the quantity of the former to be equal to 125 pounds per cubic foot, a cubic inch of it will weigh .072 pound. The volume of this deposit compared with water, is, therefore, as 1 to 12,565. Confining my observations to the city of New York alone, and taking the deposits shown in the water from the several localities around the city, the mean amount of silt in every 30 cubic inches of water is as follows: "The average of these deposits is 37.887 divided by 9 equal to 4.209; and hence, by the elements before given, it appears that the volume of the deposit from the water in the slips of this city between Thirtieth-street (east and west) and the Battery, when compared with that of the water (at half-tide,) is as 1 to 3,610. Startling as these results appear, it must be borne in mind that they do not give a full exhibition of the facts of the case, for the observations made were necessarily confined to the presence of silt, and embraced only that portion which was retained in suspension by the flow of currents; whilst the deposit of detritus from the flow of gravel, sand, &c., could not be arrived at, unless by a different system of observation, and it is, consequently, not embraced in the above results." SHIPS BUILDING ON THE LAKES. The building of vessels on the lakes for Eastern account has come to be a regular business; one has been recently launched at Cleveland for Boston account. She is 95 feet keel, 26 feet beam, and 8 feet hold, and registers about 200 tons. She costs about $10,000, and is owned one-half by her commander, Captain LEWIS, of Boston, and one half in Albany. She is christened the "Lewis Spannier," after LEWIS SPANNIER, of Albany, who presents her with a magnificent suit of colors. Experienced builders speak in the highest possible terms of the model and finish of this vessel, and her captain is delighted. The advantage to Boston merchants of building their vessels here may be understood from the fact that ship plank which is there worth $60 per thousand, can be had here, of better quality, for $18 to $20; again, spars which cost $40 here, cannot be had there for less than $100. Then, too, the vessel may make $1,000 in freight of lumber on her voyage. She will be launched in full rig and with anchors, chains, &c., complete. She will load at Sandusky with lumber for Boston. LAKE TIDES. The elevation of Lake Huron is 579 feet 7 inches, and that of Lake Superior 623 feet 7 inches above the level of the Atlantic Ocean. But that there are fluctuations in the water-level of the lakes is well established. These changes are of three kinds. First. A gradual rise and fall, spreading over a series of years. Secondly. The temporary changes due to storms and prevailing winds; and thirdly, sudden and temporary changes, attributed by some to subaqueous action, by others to changes in the pressure of the atmosphere, and various other causes. In some parts of the lakes a tide is perceptible, (as at Green Bay, Wisconsin,) in other parts the changes are said to be periodical and quite uniform. It is to be hoped that simultaneous observations, for a series of years, extending over the whole lake region, and supported by liberal appropriations, will ultimately throw more light upon this problem of high scientific interest, than the best topographical engineers now possess. A correct survey and delineation of the great inland seas of our country is demanded by the interests of commerce and navigation, and, in case of a war with our neighbors, would be of inestimable value. TONNAGE ON THE LAKES. The following synopsis will exhibit the vessels in commission on the lakes for the years 1858 and 1859, and will give some idea of the extent of the trade on these waters: Total ..... 1,442 887,740 $15,212,000 1,487 376,557 $11,536,737 It is believed that the tonnage and value of this year will exceed that of 1858. DISASTERS ON THE LAKES. Lake Michigan has been more free from wrecks than Lake Erie. Interesting data are furnished by the statements of annual losses by marine disasters on the lakes. The last four years exhibit the following figures :— Years. 1856... 1857.. Losses. Years. Losses. $782,232 1,020,100 The losses by screw propellers during ten years of lake business, show first an increase of the use of this kind of vessel, and second, the decrease in disasters as navigation has improved, and knowledge of managing propellers has advanced. THE NEW ROUTE BETWEEN THE WEST AND ENGLAND. New York has a new competitor for Western trade. The immense harvests of the West must find an outlet, and acting upon the apparent advantages to be derived from her trade, a line of British steamships has already been established between Portland and Liverpool. The Grand Trunk Railway will carry a large portion of the produce to these steamers, freighting them at once, and giving the farmers an advantage in speedy returns over New York port, where vessels are now scarce. NEW LIGHTS AT CIVITA VECCHIA AND ANCONA. Official information has been received at this office, from the Ministry of Commerce and Public Works of his Holiness the Pope, that two new lighthouses have recently been put in operation within the dominions of the Church-one at Civita Vecchia, and the other at Ancona. The figure and height of the lighthouses are not given, but they are both illuminated with the Fresnel apparatus, and are revolving white lights, the former eclipsed once in 40 seconds, and the latter once in 45 seconds. By order, WASHINGTON, July 26, 1860. R. SEMMES, Secretary. MONTAUK POINT LIGHTHOUSE, LONG ISLAND, N. Y. The repairs on the Montauk Point Lighthouse will be completed, the 1st order Fresnel lens restored to its place, and relighted at sunset on the 10th of October, 1860. The interval between the flashes will be the same as before, (2 minutes,) but about 25 per cent more of light will be visible than formerly. A new keepers' dwelling, which will be painted brown, has been built on the hill adjoining the tower. The other land marks are the same as before. By order of the Lighthouse Board, WASHINGTON, July 31, 1860. WM. F. SMITH, Secretary. LIGHTHOUSE ON MERRILL SHELL BANK, COAST OF MISSISSIPPI, INSTEAD OF THE LIGHT-VESSEL. Official information has been received at this office from Lieut. W. H. STEVENS, Corps of Engineers, that a lighthouse on a screw pile foundation has been erected on the shoal, and to mark the position heretofore occupied by the light-vessel at Merrill's Shell Bank. The foundation is square in plan, and is composed of iron screw-piles; is surmounted by a wooden superstructure, with a lantern above its center. The height of the focal plane is about 45 feet above mean sea level. The illuminating apparatus is a lens of the fourth order of the system of Fresnel, showing a úxed light of the natural color, which in ordinary states of the weather, should be visible from the deck of a vessel (ten feet above the water) about eleven nautical miles. The lighthouse will be lighted up for the first time at sundown on the 10th of August next, and will be kept burning during that and every night thereafter until further orders. On the same day, (August 10,) the Merrill Shell Bank light-vessel will be removed from her station, and will not be replaced. By order of the Lighthouse Board, WASHINGTON, July 9, 1860. WM. F. SMITH, Engineer, Secretary. SINGLE REVOLVING LIGHT IN THE GULL STREAM, ENGLAND. GULL STREAM LIGHTHOUSE. The Corporation of the Trinity-house of London has given notice, that on and after the night of the 30th of June, the character of the lights in the Gull Stream light-vessel will be altered, and a single quick revolving white light, showing a flash every twenty seconds, will be substituted for the two horizontal fixed lights at present exhibited. A single ball will be shown at the masthead by day. NORTH FORELAND LIGHT. Also, that on and after the 4th day of June, in order to enable vessels at night to keep to the eastward of Margate Sand, a red strip of light would be exhibited from the lantern of the North Foreland lighthouse, in a direction from N. by W. W. to N. E., to show from the Tongue light-vessel to one cable's length east of Margate Sand. By order, WASHINGTON, July 21, 1860. R. SEMMES, Secretary. POSTAL DEPARTMENT. LOCAL DISPATCH POSTS SUPPRESSED. POST-OFFICE DEPARTMENT, APPOINTMENT-OFFICE, July 14, 1860. SIR-I am directed by the Postmaster-General to transmit to you the enclosed copy of an order, made this day, declaring the streets in New York city post routes, and to request you to have the same published for the information of all concerned. As the act of 15th June, 1860, limits the carriers' fee for the delivery of letters to one cent, it becomes necessary, independently of other considerations, for the department, in order to sustain the carrier system, to take charge of the whole business of letter carrying in New York. Therefore, in promulgating the order of the Postmaster General, you will at the same time give notice of his determination rigidly to enforce the laws against any and all private carriers or expresses in the city, from and after the 1st proximo. Very respectfully, your obedient servant. (Signed) Hon. JOHN A. Dix, Postmaster, New York. NOTICE TO NEW YORK LETTER CARRIERS. HORATIO KING. POST-OFFICE DEPARTMENT, July 14, 1860. Agreeably to the authority conferred by the tenth section of the act of Congress of 3d March, 1851, entitled "An act to reduce and modify the rates of postage in the United States and for other purposes," it is hereby ordered that all the avenues, streets, lanes, alleys, roads, and highways in all that part of the city of New York lying south of and below 55th (Fifty-fifth) street, including that street, be and the same are hereby established as post roads. This order to take effect 1st August, 1860. (Signed) J. HOLT, Postmaster-General. THE NEWSPAPER WINDOW AT THE LONDON POST-OFFICE. It was a quarter before six when they crossed the Hall-six being the latest hour at which newspapers can be posted without fee. It was then just drizzling newspapers. The great window of that department being thrown open, the first black fringe of a thunder-cloud of newspapers impending over the Post office was discharging itself fitfully-now in large drops, now in little; now in sudden plumps, now stopping altogether. By degrees it began to rain hard; by fast degrees the storm came on harder and harder, until it blew, rained, hailed, snowed, newspapers. A fountain of newspapers played in at the window. Water-spouts of newspapers broke from enormous sacks, and engulphed the men inside. A prodigious main of newspapers, at the Newspaper River Head, seemed to be turned on, threatening destruction to the miserable Post-office. The Post-office was so full already, that the window foamed at the mouth with newspapers. Newspapers flew out like froth, and were tumbled in again by the bystanders. All the boys in London seemed to have gone mad, and to be besieging the Post-office with newspapers. Now and then there was a girl; now a woman; now and then a weak old man; but as the minute hand of the clock crept near six, such a torrent of newspapers came tumbling in together pellmell, head over heels, one above another, that the giddy head looking on chiefly wondered why the boys, springing over one another's heads and flying the garter into the Post office with the enthusiasm of the corps of acrobats at M. FRANCONI's, didn't post themselves nightly along with the newspapers, and get delivered all over the world. Suddenly it struck six. Shut, Sesame! Perfectly still weather. Nobody there. No token of the late storm-not a soul, too late! But what a chaos within! Men up to their knees in newspapers on great platforms; men gardening among newspapers with rakes; men digging and delving among newspapers as if a new description of rock had been blasted into those fragments; men going up and down a gigantic trap-an ascending and descending-room worked by a steam engine-still taking with them nothing but newspapers. All the history of the time, all the chronicled births, deaths, and marriages, all the crimes, all the accidents, all the vanities, all the changes, all the realities, all the civilized earth, heaped up, parcelled out, carried about, knocked down, cut, shuffled, dealt, played up again, and passed from hand to hand, in an apparently interminable and hopeless confusion, but really in a system of admirable order, certainty, and simplicity, pursued six nights every week, all through the rolling year. JOURNAL OF INSURANCE. INSURANCE DIVIDENDS. The following table embraces the dividends declared by the fire insurance companies of this city for the months of June and July, 1860 : : |