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10 GORRESPONDENGE. Aa We do not hold ourselves responsible in any way for the views or opinions expressed by our correspondents. It is our desire that all tides of any question affecting the interests or welfare of the lake ma- rine should be fairly represented in Tux Marine Recorp. NEITHERIS A RHUMB-LINE. To the Editor of The Marine Record: In my last communication to you, which appeared in Tur RECORD of May the 28th, 1896, under the title of “The Rhumbk-Line Controversy,’’ fourteen definitions of the rhumb-line were given in order to make sure that vesselmen on the lakes should not be led by any discus- sion which had previously taken place into the belief that there is more than one kind of rhumb-lines, as, for example, magnetic rhumb-lines and geographic rhumb- lines. ‘The essence of these fourteen definitions goes to show that the only kind of rhumb-line is the straight line on the Mercator chart, which corresponds to, or is the projection of, the loxodromic curve on the surface of the globe. That is, any straight line onthe Mercator chart which does not coincide with a parallel of latitude or a meridian of longitude. Notwithstanding the ap- pearance, in the endeavor to set matters right, of this array of definitions from standard authors, Cap- tain Pearsons, of Ferrysburg, Michigan, replies in your last issue of THE RECORD with some evidence of exasper- ation, and withthese words: ‘‘I will show him the two rhumbs, or, if it will be less offensive or less heretical, I will show him the two forms of the same rhumb side by side, and he can see their difference, and how they are derived from the same source.”’ This statement is accompanied by the following dia- gram which is cut from the published letter referred to: of S g RY St WSe Ss TS No cs Ae cal, Ry Seog ble dages —t——— f i ———— ig fi7° It is surprising, after all the definitions that have been given, and all that has been written upon this sub- ject, to find that neither of the lines marked ‘‘rhumb”’ in this diagram isa rhumb-line. The line A B is described by Captain Pearsons as run- ning due east and west, and is shown as a parallel of latitude in thediagram. It is unfortunate that, out of _the thousands of straight lines he might have picked out to represent the geographic rhumb-line, he should have selected one of the only two classes of straight lines that are not rhumb lines. The identity between the rhumb-line on the Mercator chart, and the loxodromic curve on the sphere has been abundantly pointed out in the definitions already refer- red to, and, as is well known, a loxodromic curve forms a kind of spiral on the globe, cutting all of the merid- ians under the same angle and approaching nearer and nearer tothe pole. A line running due east and west, or a parallel of latitude, cannot therefore be a rhumb- line, because it does not gradually approach the pole. According to the literal sense of the word loxodromic, foxos, slanting, oblique, and dvomos, a running course, a parallel of latitude would be excluded from considera- tion asa rhumb-line. Here are some definitions to es- tablish this point: Rhumb-Line, A line described by the course of a ship Sailing steadily in any one direction except toward any of the cardinal points: same as loxodromic curve. (Ogilvie’s Imperial Dictionary.) Rhumb-Line. A line prolonged from any point of the compass or a nautical chart, except the four cardinal points: or it is a line which aship, keeping in the same collat- eral point or rhumb, describes through its whole course. The great property of the rhumb-line or loxodrome, and,that from which some authors define it is, that it cuts all the astronomical meridians under the same an- gle. The angle is called the angle of the rhumb or the loxodromic angle. The angle which the rhumb-line Haat THE MARINE RECORD. makes with any parallel to the equator is called the complement of the rhumb. An idea of the origin and properties of the rhumb-line, the great foundation of navigation, may be conceived thus: a vessel beginning its course, the wind wherewith it is driven makes a certain angle with the meridian of the place; and if it is supposed the vessel runs exactly in the direction of the wind, it makes the same angle with the meridian which the wind makes. For example: a wind that is north-east, and which of consequence makes an angle of 45° with the meridian, is equally north-east, wherever the wind blows, and makes the same angle of 45° with all the meridians it meets. A vessel therefore, driven by the same wind, always makes the same angle with all the meridians it meets with on the surface of the earth. (Falconer’s New Uni- versal Dictionary of Marine, London.) Rhumb Line. Tf the vessel sails either due east, west, north or south, she evidently describes a circle on the earth’s surface; but if she sails in one constant direc- tion toward the same intermediate point of the compass, thus preserving a line which cuts the successive merid- ians at a constant angle, she will describe, as any one may see by drawing such a line on the sphere, a spiral. (Encyclopedia of the Sciences by J. P. Nichol, LL. D., London and Glasgow.) Rhumb-Line, A line described by the ship’s motion on the surface of the sea, steering by the compass, so as to make the same or equal angles with every meridian. These rhumbs are sfzra/ ines proceeding from the point where we stand, and winding up the globe of the earth, until they come to the pole, where at last they lose themselves, but in Mercator’s charts, and in plane ones, they are represented by straight lines. These lines are called vhumb-lines. (Etymolo- gical Dictionary of the Eng- lish Language, W. W. Skeat.) The second line, marked A G in this diagram which $ purports to show two rhumb- R lines, is a curved line. No line which is curved on the Mercator chart can be a rhumb-line,because,as pointed & out in the communication of May 28th, the Mercator pro- AGca He ray jection may be said to result \ from the development on a plane of a cylinder tangent to the earth along the equator, the various points points of the earth’s surface having been projected upon the cylinder in such a manner as to satisfy the follow- ing condition: That the loxcdrome, or shzp’s track on the surface of the sea, under a constant bearing, shall appear on the de- velopment as a straight line. Captain Pearsons concludes his letter with the state- ment: ‘I'he United States authority, knowing the dif- ference between the ship’s track and rhumb-line, puta saving clause into their definition and give us to under- stand that while the ship makes the angle with all the meridians she crosses, the track is called a rhumb-line.’’ ‘They are quite safe in calling the ship’s track the rhumb- line on this condition, for no ship, as we have seen from the preceding discussion, ever sailed on the geographic rhumb, when steered to a constant magnetic course.’’ Iam not aware that it is anywhere stated upon au- thority that a ship sails along a rhumb-line when steered to a constant magnetic course; on the contrary it is everywhere understood that, in order to pass along a thumb-line, the ship must be steered toa constant true course. As has heretofore been pointed out, this is ac- accomplishedin practice by changing the direction of the ship’s head at convenient intervals along the route to compensate for the accumulated change in the variation of the compass in those intervals. ‘This is the universal practice of mariners, and it must be attended to as rigidly by every captain who carries on trade between New York and Kurope as it is on the lakes, for the change of the variation of the compass per one-hundred miles along the transatlantic lanes of commerce between New York and Halifax is greater than on the lakes. Very respectfully, G. W. L. Washington, June 18. The marine department of the Maryland Steel Works, at Sparrow’s Point, Md., has closed down. THE NEW PROVIDENCE WINDLASS. Owners contracting for vessels, if they are not thoroughly acquainted with the poimts of different windlasses offered to the public, should investigate the different styles before making their contracts, so as to be sure to get the best. The American Ship Windlass Co., of Providence, R. I., court the most thorough inves- tigation of their machines, and feel perfectly sure that if the public knew the advantage which their ma- chines have over other styles they would not accept any other style, particularly as the ‘‘Providence’’ machines could be had by the simple trouble of calling specifically for them in the contract. In the “Providence” wind- lass every point has been provided for by close study of its operation in practical use for over forty years. Their latest style of improved windlass embodies advantages which previous styles have not had, and is up to date in every respect. quae ee TRADE AND INDUSTRIAL NOTES. The Marine Iron Works, Chicago, report that they have been fairly busy during the past two months, in the line of complete outfits of marine machinery for boat builders and others building their own hulls, the boats ranging in size from 35 to 100 feet, and in style from very light draft paddle-wheel machinery to single- screw deep water work. The Carneg'e Steel Company has decided to build a $1,000,000 addition to its extensive plant. A_ site has been selected above the Homestead mills for a large forging and finishing shop to forge heavy propeller and steamship shafts and heavy gun forgings. The plans are nearly completed and contracts are almost ready to be let. The plant will be equipped with hydraulic hammers, presses and other machinery of the best class, making the establishment, it is claimed by the company, without a rival in the world. The King Bridge Company, of Cleveland, will erect the South Rocky River bridge at this place. The con- tract was awarded to McAllister & Dall, who sublet the work to the Kivg Bridge Company for $84,000. The Lake Superior Power Co., Sault St. Marie, Ont., Canada, intends to establish a plant for the reduction of ores by electricity and the manufacture of calcium carbide. : Good work is being done at the new Pioneer furnace of the Cleveland-Cliffs Co., at Gladstone. Though the rated capacity of the furnace is 30,000 tons a year, a record of 127 tons in 24 hours was made recently. The H. P. Nail Co., Cleveland, is putting in machin- ery for the manufacture of weldless chain, trace chain, logging chain, coil chain and other specialties of 1% inch stock, and smaller will be made. : ‘The Sharon Iron Works, of Sharon, Pa., will build a mammoth steel department, with a capacity of 1,500 tons per day, to its works. It will cost over $500,000. They will also add a department for the manufacture of rods and wire out of steel. The lighthouse tender Rose, at Ramsay’s yard, Perth Amboy, N. J., has recently been supplied with a Mori- son suspension furnace by the Continental Iron Works, Brooklyn. The Gas Engine and Power Co., of New York city has filed at Albany a certificate of increase of its capital stock from $150,000 to $600,000. ‘The company’s state- ment shows a paid in capital of $150,000 and debts only $5,000. This is the financial part of the extension of business by this company with its new combination re- cently referred to, the outlook for which is so promis- ing.—Marine Journal. The Menominee (Mich.) Iron Works Co. is about to erect a foundry 60x100 feet, to be equipped with the latest appliances. Plans have been prepared for the enlargement of the plant of the Frontier Iron Works, of Detroit, by the addition of a fourth story, 48x148 feet in size. The ad- dition will cost $7,000. KE. X. Roberts, president and general manager of the Roberts Safety Water Tube Boiler Co., returned Monday from a trip to Pensacola, Fla., where he has been in- stalling one of the company’s boilers in the United States revenue cutter Penrose. It was found to work very successfully, as was to have been expected, and Mr. Roberts also picked up other orders.—Marine Journal. —_—_-e 29 — rr _ Beeson’s Marine Directory for 1896 is full of marine information of great value.—Detroit Evening News.