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MARINE 1901.] REVIEW. 23 caused by minor projections and irregularities in the surface of the smaller ships, these irregularities being on a proportionately larger scale in the smaller than in the larger vessel. It must also be borne in mind that any roughness of sea or wind has a greater effect in proportion on the smaller ships, tending to spoil their performances on trial, as com- pared with those of larger ships. I do not intend, when I use the term '"'economical" speed, to make it include the financial side of the question; as it frequently happens that it is cheaper to increase horse power, to get a little extra speed when required, than to increase the length of the ship, or to fine her lines. What I intend to convey is that, if a speed be aimed at, slightly above the limiting speed I have defined, with the indicated horse power increasing as more than the fourth power of the speed, it will be found possible to drive at that speed, with the same horse power, a vessel increased in one dimension, viz., in length, and proportionally increased in displacement. Whilst, if a still higher speed be aimed at, the vessel may be increased in two dimensions, viz., length and draught, or length and beam, and still attain the higher speed, with the same horse power as the smaller ship. Finally, as was proved by the late Mr. Froude, when the indicated horse power is increasing as the seventh power of the speed, it is possible to drive a similar ship, increased in all three dimensions, at the same speed, with the same horse power as the smaller vessel, and this is more than borne out by the facts. I have shown that the indicated horse power is usually increasing at this rate, viz., as vy', when skin horse power = wave horse power, or at about 12 per cent. above the limiting speed. This is then the speed at which it becomes economical to increase all the dimensions of the ship in the same proportion; of course, from the point of view of driving the greatest displacement at the given speed. There are many vessels in which this limiting speed is far exceeded, such as fast cross-channel passenger vessels, torpedo gunboats and de- stroyers; but these type are for very special requirements, and are not eco- nomical in the sense of carrying large displacement at the required speed. They are not, therefore, included in the scope of this paper. Nor do the figures I have given.apply to vessels of very great beam in proportion to their length. The examples I have taken are all of ordinary proportions, not less than 6%4 beams in length, and of ordinary draughts; but, as this includes practically all mercantile vessels, and also cruisers of the usual dimensions, the range is fairly wide. In these two latter classes the num- ber of indicated horse power per ton of displacement rarely exceeds two. In the slower vessels of the mercantile marine it goes as low as &% indi- cated horse power per ton of displacement. In the torpedo boat destroyers it goes as high as 20, and in the Viper, with the turbine machinery, has, I. understand, reached about 30. So that the exclusion of these very fast craft from a paper dealing with the economical side: of the speed and horse power problem is obviously reasonable. The very broad vessels, also to some extent abnormal, have therefore been excluded, as have also the performances of paddle-boats. As regards the comparative per- formances of single and twin screw vessels, there appears to be little difference in vessels of good form. Reverting to the limiting economical speed as defined, I find that, generally, for 1 per cent. increase above this limit of speed, 5 per cent. increase of horse power is necessary; and at the speed when skin horse power equals wave horse power, or about 12 per cent. above the limiting speed, 1 per cent. increase of speed requires 10 per cent. increase of power. Taking these figures, it appears to me that any increase of speed above the limits indicated should be most carefully weighed before adopting it, in view of the disproportionate increase in power and weight of machinery thereby rendered necessary, together with increased engine room staff, the larger coal bill, and the reduced weight and capacity for cargo. I think there are ships that might well have been made finer, or have had their speed and power reduced when in the design stage, at the cost of foregoing that last half knot, which possibly requires from 20 to 25 per cent. additional horse power, enabling the vessel, perhaps, to steam a distance of 12 knots farther in twenty-four hours at the cost of burning out coal which would keep her a whole extra day at sea at half a knot less speed, and this without taking into account the original saving in weight and cost of machinery which might have been made. In conclusion, I would say that I have had great difficulty in obtain- ing reliable data of progressive trials of ships with very large coefficients of fineness. In these vessels, usually, no progressive trials are made, and, in any trial that does take place, frequently the propellers are only par- tially submerged. : WHEN ENTERING BUFFALO. Com'dr Dunlap, inspector of the tenth light-house district, reports that there have been some complaints of late that the fog signal in Buffalo harbor is not sounded when the conditions of the atmosphere require its operation. Investigation of these reports shows that the dark background of the south shore of Lake Erie near Buffalo often makes it difficult for the keeper in charge of the fog-signal to discriminate between the hills on the shore and dark clouds of smoke which sometimes settle over the lake in that direction. Vessel masters entering or leaving Buffalo harbor in thick or smoky weather and needing but not getting the assistance of ° the fog signal, are requested to sound their own whistles frequently, and in such cases the keeper having charge of the fog-signal will at once begin to sound the bell and make immediate preparations to get the fog- signal in operation as soon as possible. The conditions referred to above do not frequently occur, but if vessel masters will heed this request of the inspector, he believes there will be no further cause for complaint. The Oceanic Steamship Co, is experiencing considerable difficulty in connection with its service between San Francisco and Sydney. The Sonoma was delayed in Port Jackson eight days after her sailing date, having to be docked for repairs, and the next incoming sister, the Ven- tura, was not allowed to discharge cargo at the Sydney wharves, owing to a reported case of plague in San Francisco. The fact that the reported case had not developed at the time the Ventura left made no difference to the health authorities. In point of fact the case had never developed at all. Considerable indignation over the action of the health authorities was expressed in Australian shipping and maritime circles. ABOLITION OF THE INSIDE STATEROOM. Mr. A. W. Bibby of the Bibby line, and chairman of the Pacific Steam Navigation Co., has solved the vexed problem of the inside stateroom. On long voyages, and particularly on vessels which have to pass through tropical waters, the inside stateroom is undesirable. It is difficult to light and ventilate it and it has no communication with the side of the ship. A system has been devised by Mr. Bibby 'by which the inside stateroom has been done away with. Mr. Bibby has invented the tandem stateroom. So simple is the arrangement, and at the same time so effective, that it is remarkable that a system which confers such benefits was not put into operation long ago. The illustration clearly explains the arrangement. At right angles to the main alleyways are passages common to four state- rooms, two on either side, while in each passage is a porthole. 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In this tandem arrangement one stateroom has a porthole in its widest part, while the other has a port- hole (under which is a comfortable seat) in 1ts narrowest part. Thus both cabins enjoy the advantages of direct communication with the side of the ship and hence the obnoxious inside stateroom 1s abolished. The evolu- tion of this simple and effective method of equalizing the berthing accommodation on shipboard is interesting. The first tandem stateroom was built from Mr. Bibby's designs by Messrs. Harland & Wolff of Belfast, Ireland, at whose famous yard the whole of the Bibby' fleet has been constructed. When the model was completed its utility was mani- fested at once. It is now being applied to steamers building at the Harland & Wolff works and at the Fairfield Co.'s yards in England. Steamers of the British mail service are also being equipped with this ingenious arrangement of staterooms. To Buffalo and return, $3.70, eyery Tuesday and Saturday until fe- called. Good returning within three days on any regular train, including train leaving Buffalo at 1.00 (central time) or 2.00 (eastern time) after midnight of the third day from date of sale. For specific information call on E. A. Akers, C. P. & T. A., 189 Superior St., Tel. Main 218, Cleve- land, Ohio. ; 135, Aug. 16