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42 THE MARINE RECORD. MAvy 30, Igor. 8 LhLrr—C—“™ESCS A TRUSCOIT BOAT SIMPLE, SAFE, RELIABLE, SPEEDY. lighting. It may be possible to build better and _ safer boats. but it hasn’t been done yet. We send a: completely jilustrated catalogue and price list free, which tells you all about boa s and WHY TRUSCOTT BOATS EXCEL. Truscott Boat Mfg, Co. ST. JOSEPH, MICH. Pintsch Gas Lighted Buoys. Adopted by the English, German, French, Russian, Italian and United States Light-House Departments for channel and harbo: Over 1,000 gas buoys and gas beacons in service. , Burn Continuously from 80 to 365 days and nights without attention, and can be seen a distance of six miles. . Controlled by THE SAFETY CAR HEATING AND LIGHTING CO. 160 Broadway, New York City. : THE LAW OF MAGNETISM. A SHORT AND CONCISE LESSON ON MAGNETISM AS IT AFFECTS THE MARINER’S COMPASS. BY CLARENCE E.. LONG, MILWAUKEE. (Arranged for Masters and Pilots on the Great Lakes. ) CHAPTER VIII. MAGNETIC VARIATION. It is very important that the navigator should have, a thorough knowledge of the Magnetic Variation. The amount of allowance and its direction, and annual change - are indicated on the charts. On all Mercator charts, with the exception of harbor charts, will be found irregular lines running from the top to bottom of the paper in a north- The above method of applying the Variation may be used where there is ample room, but on long routes where the Variation changes rapidly, to apply a single correct magnetic course to be steered all along the line, might lead to dangerous results. Long, straight routes should be sub- -divided-into—parts and-the-correct--magnetic -course given for each part. However, on most lake rotites it is practicable to take the mean of the two variations. Remarks :—If the variation at departure was easterly and westerly at destination what would that indicate? It would indicate that in order to reach your point of destination you will have to cross the line of no variation, In a case of this kind just take one- half of the variation at the departure and apply it to the ‘true course and this will give the proportional variation be- ‘tween the starting point and the line of no variation. When westerly and southeasterly direction, and having beside _the variation at destination and apply it to your true course. them such inscriptions as 5 deg. W., 8 deg. E. This means that along this line the Variation of the compass from true | north is W. 5 deg., 8 deg. E. There are certain lines, which have no Variation, and here no allowance is to be made. There is one such line in the region of the Great Lakes. It across the Straits of Mackinac down through central: Mich- igan. This line is called the “Line of No Variation.” All places to the east of this line of no variation the variation is westerly, and all places to the west it is easterly. West- erly variation is increasing and easterly variation is de- creasing, or in other words the line of no variation is mov- { you have crossed the line of no variation take one-half of For example: The true course from Copper Harbor to Whitefish Point iis E. by S. %4 S., distance 145 statute miles. The line.of no variation crosses this course at a point 30 miles from White- passes through the east end of Lake Superior, thence | fish Pt. The variation at Copper Harbor is 2 deg. 16 min, EF, one-half of which would be 1 deg. 8 min., equal to % of a point, nearly, and giving the correct magnetic course to be E. by S. 3 S. From the line of no variation to White- ' fish Pt. the variation is westerly, being 2 deg. 20 min. at _ ing west. On harbor charts’the variation is shown by the | compass card printed on the chart. The north point of it will be found slewed a little to the eastward or westward | of a meridian line. On all Mercator charts, inside of each » compass rose will be found an inscription such as ‘Var. 8 deg. E, in 1898; decreasing 5 min. annually.” On the | charts published by the Engineers’ Dept., you will find a table of Magnetic Variation, or Declination, giving the variation for the different localities with the annual in- crease and decrease. ANNUAL CHANGE IN “THE VARIATION. A knowledge of this is very important, as in many parts of the world it is very rapid, and after a few years the cor- rection becomes quite a consideration. Masters are not al- ways acquainted with this peculiarity of terrestrial mag- netism, and, in consequence, give courses which were the ‘correct thing years ago, but are so no longer.. It is evident, from what has just been stated; that correct. magnetic courses given in sailing directions need revision in a com- ' paratively short time. A man with a chart and possessed of the above knowledge, does not require stich dry nursing. _ TO ALLOW FOR VARIATION BETWEEN DEPARTURE AND DESTI- NATION. To apply the Variation to a True Course, to obtain. a Correct Magnetic Course, between a point of departure and - a point of destination add the two Variations together if they have like-names, that is, both east or both west, and * take the mean of the sum by dividing by 2. The quotient ~ will be the proportional variation to be applied to the true course between the two points. For example: Variation at Chicago.............. 2° 49 EB. Variation at Twin River Pt........ 2° 15’ E : 2) 5° 04’) Variation to be applied............ 20°32" Hh, the latter place, and one-half of this would be 1 deg. 10 'min., equal to % of a point, nearly. At the line of no variation the course would have to be shifted to the right that much, or E. by S. % S. TO CORRECT FOR ANNUAL CHANGE IN VARIATION. To correct the Variation for the annual change multiply , the number of years that have elapsed since the chart was corrected. Remember, that easterly variation is decreasing and westerly is increasing; therefore, when correcting easterly variation subtract the annual change, and westerly add it. For example: The Variation at Chicago in 1898 was 2 deg. 49 min. E., annual change 4.7 min. What will the correct variation be in 1900? Variation at Chicago 1898.......... 2° 58.40 Bi Decreasing annually 4.7’, 2 years... 9.4’ (subtract) Correct Variation at Chicago 1900. .2° 49 0’ EB. Example :—If the annual change in the Var. is 5 min., how many years will it take to effect the Var. 1 deg.? Ans. 12 years, because in 1 deg. there are 60 min. and 5 min. is contained in 60 min. 12 times, or 12 years. OPPOSITE AND REVERSE. _ Do not get the terms “opposite” and “reverse” as ap- plied to the compass mixed up with each other. Mariners, generally, are a trifle out of their latitude on this seem- ingly “knotty” subject; but there is no reason for con- fusion as there is a marked distinction between the two terms. The average person will use reverse and opposite as meaning one and the same thing in speaking of the directions on the compass, or horizon, as for instance, they will tell you that SE. is opposite NW., but this is not so, the opposite of SE. is SW. and NW. is the reverse of SE. For an example, we will take the sun. Now, the sun always sets in an opposite direction to that of its rising, that is, if it rises at E. by N. it will set at W. by N.; the azimuth remaining the same from north or south for ris- ing and setting. CONCLUSION, When I started it was not my intention to write more than one-fourth of What I have, but were it not for the lack of space 1 might write ten times more on this im- portant subject. As I said before, an exhaustive inquiry into this important matter would require a good sized vol- ume, therefore, it is impossible to treat it in a work of this kind, and I trust that no one will expect it, My idea in taking this short preliminary canter round the out- skirts of the subject is to. call attention to some of the most important details appertaining, to the adjustment of compasses and the laws of magnetism. . ‘Yours very obediently, CLARENCE E. LONG, Scientific Compass Adjuster, Principal Milwaukee Nautical . School, 140-142 Reed, St., Milwaukee, Wis. Ooo? VISIBLE SUPPLY OF GRAIN. As compiled for THE MARINE RECORD, by George F. Stone, Secretary Chicago Board of Trade. CITIES WHERE .| WHEAT.| CORN. OarTs. RYE. BARLEY STORED. Bushels. | Bushels. | Bushels. | Bushels. | Bushels. Bulalo 23.55 3cchics 3,5¢8,000 892,000 824,000 16,000 479,C00 EN aA Geta: ele (oh he once a ciel SSE eke ee ered eters" Chicaroes icin. 7,616,000] 5§.975,00¢|} 2,899,000 188,000 155,000 WME OM er aca uitiiae cance ats peer aE Raeyoes ar adea Pid ee | eet eS ae Detroit...... 211,000 147,000 1,0 0 5,000 2,C00 Duluth....... 6,013,900] 3,549,000) 1,180,000 259 00¢ 44,000 “ afloat... SN US 5 De alee ears S| PhS ea i ea ae Fort (William: Ont... Paps8u 000 sie, Meee teh ee Ne pe Milwaukee......... 517,000} 682,00c]| 344,000 18,000 16,0co #0. a Moats cis. s aok cil oracras ages eas de conte eee Sisiacal| Omuespeeetc line pba aaeakee 8 ear ans Port Arthur, Ont.. EAGMOOL at et lol Ce atccme we ee eee ee i MOVE AOieo sites 198,000] — 413,00¢ 189,000 1,000 1,000 TOLONtO ye iui et 50,000]........ EQN rate ac cet 60,000 On’ Canalseccs re. : ATBsOOO Cs ews ence 353,000 105,000 19,000 Ons Gakesiacrs gs: 2,751,000} 1,095,000 161,000 15,000 31,0co On Miss. River...... QO\OOG He uk. cena vera tecue lhe 5 cone oneaets sacar Grand Total..... 40 064,000} 15,320,000] 10,438,000 699,000! 1,061,000 Corresponding Date, WSOC ese Seeds se, 44,755,000) 12,687,000) 6,786,000} 1,067,000] 944,000 IMCTEASE..... cece cece eee reece elonee tase OP te Se oad WER oes 143,000 Decrease ........... 2,434,000 593,000 286,000 163,000" (co sone While the stock of grain at lake ports only is here given, the total shows the figures for the entire country except the Pacific Slope. —— i oe ANENT the recent transfer of the Leyland Line of steamers to the J. P. Morgan syndicate, a joke used to be told on a Liverpool reporter. The Leyland Co was the first firm to build 4-masted, 4oo feet, flush decked, iron steamers for the Mediterranean trade. It so happened that several of these boats, inward and outward bound, were lying in the river Mersey at one time, and the reporter, to be briefly truthful, reported half a mile of arian’s in the river, the names of the vessels in the fleet all ending with—ian. A tow of 400 foot steel vessels was strung out abreast of Cleveland last week having a gross register tonnage of 20,000 and an easy dead weight carrying ability of 30,000 tons, as follows, the steel steamer General Orlando M. Poe, with barges John Fritz, John Smeaton, W. Le Barron Jenny and the Alfred Krupp, built for, and formerly owned by the Bessemer Steamship Co. (Rockefeller Line), and now inthe syndicate of the United States Steel Corporation, known as the Pittsburg Steamship Co. This string of floating steel warehouses, fairly in line, with taut hawsers monopolized about 4-5 of a mile of lake frontage, the Krupp was dropped at Cleveland, and the rest headed for Lake Superior,