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MARINE REVIEW. II Comparative Trial of Boiler Tubes. An interesting tria was made recently be- tween plain andribbed boilertubes at Moore’s shipyard, Elizabeth- port, N. J. The result of the trial showed an economy of 27% per cent. in favor of the ribbed tube.. The boiler used was a usual upright tubular of 42 inch diameter, with 36 inch furnace, ae 24 inches high and 63-2% tubes 6 feet long, 7 square feet grate surface, 287 square feet fire surface. These trials occupied twelve days, six with the plain tubes and six with the Serve ribbed tube. Each day’s trial lasted 8 hours; 32.35 pounds of wood and 150 pounds of coal were used to start the fire and to raise steam to 70 pounds pres- sure, after which the trial was immediately commenced. Steam was kept at 70 pounds pressure, and the water level at 7 inches in the glass as nearly as possible, and both were at these points at the end of the trial. Following is a tabulated statement of the results : Pounds of Coal per roo Pounds of Water Evap- orated. Increase Econoniy Gn : iS oe Cc sie ae ho Plain | Ribbed P- & | generated tubes. tubes. — eee ee Be ee ee | ee a | Natinaladratt Shiics. iieeti sc cones 19.72 13,65 (30.83 p.c.| 18.03 p. ¢ Forced dealt: 5058s. ices ss. Scesis os 16,76 6) e61321-2 121,08 pc |°3097 p. Cc Bomved Araht FG ccagsicensivess soccer.» 21237 14.8 |30.74 p. c. | 46.46 p. c E | vapora- | Increase by Serve tubes Total tion per_| ew padbeas? eve RETO Tihs. of evaporation plain tubes. MOR. 1 a tistn| P ; Naturaledratt 6 sccn ry cau sce -oe 2s 18.03 P- C-157-54 p. c.| 8,460 lbs. for plain | | | tube, Forced draft %....... +02 Sa 30.97 Pp. C./32-68 p. ©.|14,000 lbs. for ribbed | tubes. Borced drat: (oc. c:. 225505. 02 s000--+>s 46.46 p. c. 46.84 p- c. Increase 65.5 per ct. The soot scraped out of the plain tubes after asix days’ trial was 2% pounds. ‘That scraped from the Serve tubes after the six days’ trial was 3 pounds. These tubes are now being placed in the Pennsylvania, of the Keystone line between Philadelphia and Liverpool, and 522 Serve tubes and 6 Purves furnaces are being supplied to the Mascotte, of the Plant Steamship Line. For detailed information write C. W. Whitney, sole agent, 81 Fulton street, New York. “THE MICHIGAN” ISSUES POLICIES ON HULLS AND CARGOES ON FAVORABLE TERMS. IT IS FOR THE INTEREST OF THE OWNERS OF THE LAKE MARINE TO BUILD UP A HOME COMPANY BY THEIR PATRONAGE. AGENCIES AT PRINCIPAL PORTS. a a SR A RL RE Books Received. “Tron Ores of Minnesota” is the title of as valuable and hand- some a book as has been published on the subject of iron ore. It contains dotailed information of different mines on the Ver- million and Mesaba ranges, and the properties of the different ores are shown by lithographed illustrations. By sending twen- ty-three cents in stamps to N. H. Winchell, Minneapolis, Minn., interested parties will receive a copy of the book. “Scott’s Coast Pilot,” corrected to 1891, has been received. It contains a list of all lights, light-houses, fog signals and buoys on the lakes with instructions for entering harbors. The sailing directions are compiled from most reliable sources, and have been tested by forty years’ experience in practical sailing. If you have not purchased a copy, write the MARINE REVIEW, and you will receive the book and this paper one year for $3.00. ~ “Better than Gold” and “Ourselves and Our Neighbors” are titles of two books bound in one volume, written by ee Pomeroy, who, as he tells in this book, has battled fate harder than any other living man. As president of the Atlantic-Pacific Tunnel Company he is on the up-hill road once again. He re- cently took a party of directors west to look at the property. If you want a copy of his book send one dollar to publishers, 46 Pulitzer Building, New York. - Insurance Company of North America. INCORPORATED 1794. LAKE MARINE DEPARTMENT, CEO. L. McCURDY, Manager, Chicago, Ilis. CHARLES Pratr, President. WiiurAM A. Piart, Vice-President. EvuceEnE L. E.Ltison, 2d Vice-Pres’t. GREVILLE E. FRyxR, Sec’y & Treas. Joun H. Atwoop, Assistant Secretary. Capital, pales U6 CAG censee vne-n0n $58 Se serpane! $3,000,000 00 Assots. ...-5:4:s:ceaeea as ees a atl 8,951 518.83 Commercial Union Assurance Company, Limited, OF LONDON. INLAND MARINE DEPARTMENT. DAVID VANCE & CO., General Agents, MILWAUKEE, WIS. Local Agents at all Lake Ports. INSURES HULLS, CARGOES. FREIGHT. O ENGINE AND BOILER MAKERS. — Office of Light-House Engineer, 9th and 11th Districts, Detroit, Mich., May 8, 1891. Sealed Proposals will be received at this office until 4 o clock Pp, M., of Monday, the 1st day of June, 1891, for furnishing the boilers, machinery, ete., for «ight steam fog s gnals, in sets of two, deliv- ered at the Light-House Depot, Detroit, Mich. Plans, specifications, forms of proposal, and other informition may be obtained on applica- tion to the undersigned, The right is reserved to reject any or all bids and to waive any defects. WILLIAM LUDLOW, Light-House Engineer. tion. U.S. Engineer Office, Buffalo, N. Y., April 30th, 1891. Sealed proposals, in dupli- cate, for excavation of material at the following points, will be received at this office until 2 rs on Saturday, the 30th dav of May, 1891, anc opened immediately thereafter in presence of bidders: Oleott Harbor, N. Y., between the piers, Oak Orchard Harbor, N. Y., between the piers, Niagara River, N. Y., near Strawberry island. The attention of bidders is invited to Acts of Congress, of February 26, 1885, and February 23, 1887, vol. 23, page 332,and vol. 24, page 414, Statutes at Large. 5 yecifications, gen- erral instructions to bidders, blank forms of pro- posal, or necessary information, will be fur- nished on application to this office. The United States reserves the right o reject any or all proposals. AMOS STICKNEY, Major of En- gineers, U.S. Army. May 28, Potion. -u. FOR CHANNEL EXCAVA-