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14 MARINE REVIEW. Low Cost of Producing Ore. Everybody interested in Lake Superior mines is talking of the year's record at the Oliver, the greatest of the Mesabi steam shovel mines. Some figures printed in Duluth recently regarding cost of mining at this property are so low as to cause great doubt regarding their accuracy, and yet they are put in such a way as to indicate a reliable source. These figures show the mine to have run its 810,000 tons of this year's output for about 64 cents a ton, exclusive of strip- ping, which is set down at not over 3 cents on a total ore body to be mined by the shovels. While this is probably too low, it gives an idea of the exceedingly low cost of mining that has been enjoyed by the Oliver this summer. In this connection it is interesting to note that the management of the mine has determined to mine their entire ore body by steam shovels, and that it is not considered necessary to make provision for any change to either milling or other underground process later. Ore will be raised out of the mine, when its level shall have been sunk too far for present methods, by pneumatic elevators or stationary engines for lifting the loaded cars to the surface, or by running switchbacks or circular tracks down the mine. It is stated that some of the largest and best managed Mesabi mines operated under- ground by the caving process have shown cost sheets this year of not far from 40 cents, and ranging from 37 to 41 cents per ton, including everything. This figure is vouched for as accurate by one of the best known mining engineers in the Mesabi region. In General. _ "Blinker"? and "twinkler" are the names applied to the gas buoy on the middle ground in Point Pelee passage. The name comes from the flash that is characteristic of the light. Italy proposes to build within the next ten years twenty warships of various classes, one hundred torpedo boats, and ten auxiliary or harbor service vessels. This includes an expendituré of $60,000,000 by 1907, and active discussion is going on concerning the maintenance of the fleet. Commodore K. Martia' another representative of the Japanese navy, is in San Francisco, and announces that he will spend several months in this country and in England looking into naval matters with a view to making 'reports upon which his government will base plans for war ships. Two twin-screw steel passenger ferry boats of large dimensions are under construction in Philadelphia for the Pennsylvania Railroad Co.--one at the yard of the Cramps and the other at Chas. Hillman' . & Co.'s yard. The boats are duplicates and will be called Pittsburg -and St. Louis. The Pittsburg was launched at Cramps' yard a few __]- days ago. She is 206 feet over all, 184 feet between rudder posts, 46 feet moulded beam, 65 feet over guards and 15 feet average depth. There are two sets of triple expansion engines with cylinders 20, 32 and 32 inches in diameter by 24 inches stroke, each turning two propeller wheels on either end on a continuous shaft. These propeller wheels, four iu number, will be 8 feet 3 iachesindiameter. Each engine 7s to develop 1,500 horse power. Steam will be generated by four water tube boilers, having a working pressure of 200 pounds to the square inch, The NewYork newspapers have just awakened to the fact that the $9,000,000 appropriation for canal improvements in New York state will not be sufficient to make any great difference in the size of the canal boats. One of them gives upa couple of columns to statistics covering the wonderful increase in St. Mary's Falls canal traffic originating in the northwest and adds this comment: "In view of this great volume of commerce it seems remarkable that all that New York proposes to do to retain the big grain traffic which comes to her through the lakes is to deepen the Erie and Champlain canals by only 2 feet. For the Empire state to have shown a curious indifference to her own business interests seems incredible indeed. New York busi- ness men seem to think that the traffic will come this way perpetually, no matter if the Erie canal is not improved. But it won't. There is a great empire west of Lake Michigan and Lake Superior which must have an adequate outlet, and if it can not get it through New York state it will get it down the St. Lawrence. In a few years there will be fifty million tons of freight pouring through the great lakes, and the urgent necessity brought about by such conditions will compel abrupt attention to the construction of an adequate outlet to the sea. The present is the time, however, to agitate the subject." as. well as St. Lawrence river charts Nos. 4, 5 and 6. Hydraulic Dredging. The special advantage of the hydraulic dredge is the transporta- tion of the dredged material and its delivery at a considerable dis- tance. Although it is especially applicable to land reclamation where the material has to be spread over considerable areas of low-lying land, it would seem that a great deal of work done with dipper dredges might be more economically accomplished with the hydraulic sytsem. Land reclamation work is performed by the hydraulic dredge ata very low cost, because it combines in one operation the work of dredg- ing, transporting and evenly spreading the material. The Suez canal could now be duplicated for about one-third of its cost. The Nicaragua canal, although entirely different as to its con- ditions, can be built for a less sum today than was before thought possible. In general terms it may be said that the hydraulic dredge is adapted to work under conditions where the material is homogen- -eous, that is to say, free from large obstructions, and where a fluid or semi-fluid discharge can be provided for. This discharge may be at any distance uptoa mileor more. By homogeneous material is meant sand, clay, earth, gravel, alluvial deposit, and, in fact, anything that does ot contain tnree obstructions, such as Pouiers, roots or stumps, etc., and any material which can be disintegrated by plow or cutter. All such material is capable of being carried through a pipe, when mixed with from 60 to 90 per cent. of water, the amount that can be carried in suspension depending on the distance, velocity of flow and character of material. Stones and other objects of consid- erable size can be washed through the pipe; in fact, any solids can be carried that will pass through the openings in the pump. The form of pump commonly employed is the centrifugal. For dredging pur- poses this is made extra heavy. The internal passages should be large and free, and with curves of large radius. The interior of the pump is sometimes fitted with lining plates to take the wear and abrasion. This wear, however, is not great, and a well-designed dredging pump is about as durable as any other kind of dredging machine. --Cassier' S Magazine. f The benefit of feed water heaters on lake steamers has been dis- cussed with different conclusions but nearly every one agrees that some kind of boiler compound is necessary. A feed water heater that delivers the water at a high temperature and delivers it free from impurities is certainly worth investigating. On eighteen Anchor line steamers, as well as four large wooden steamers, the steel steamer America and the steel passenger steamer Manitou; there: are. heaters having these two and other advantages. They are known as the ' Buffalo heaters, and the inventor is a practical lake engineer, R. Lear- month, 200 Lafayette avenue, Buffalo, N. Y. In addition to those in lake 'steaemrs, he' has place heaters in some large stationary plants, where they are giving satisfaction. In one case chemists pronounced the water unfit for. oilers but with these heaters all the deleterious matter was taken out. Boilers representing 28,000 horse power are "equipped with this device. Some valuable ntouniition! concerning feed water will be found in a catalogue which will be mailed by Mr. Learmonth to any address. Now that the Lake Ontario grain movement is increasing, masters vill want Lake Ontario general cnart No. 61 and coast chart No. 1, The five will be sent by the Review to any address by express for $2. Robert Morrill of Collingwood, Ont., has just launcheda small steam vessel. Her dimensions are 92 by 16 by 74 feet. In a large number of cases the Blue Book of American Shipping has been sent on approval to ship owners, ship builders, marine engi- neers and others interested in shipping. In every case the price of the book, which is $5.00, has been remitted immediately. Hunters' excursion rates are offered by the Nickel Plate road to points in Michigan, Wisconsin and the southwest. 339 Noy. 1. EOR SALE, Naphtha Cruising Launch, 38 feet long, 8 feet beam, cabin with four berths, with wash room, ice box, and all modern conveniences, beveled edge plate glass windows, and mahogany finish throughout. Speed 10 miles per hour, bran new last year, and for sale cheap for cash if taken at once. For further particu- lars address Box 616, Toledo, O. Dec. 1