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34 WHEN THE DIRECTIVE FORCE IS GREAT. - Where it occurs that the directive force on the compass is increased, or is much more than-it would be from that of the earth alone, is on and near the courses that are in reverse of the direction of the ship's head in building. In this in- stance the two forces act as one, hence the fickle and wild state of the compass. THE OBJECT OF COMPASS ADJUSTMENT. It is the object of compensation by magnets to relieve the compass of this inequality of directive force by equalizing it (nearly) on all courses. While this is the object of compensation (compass adjusting) it cannot always accomplish its purpose. This occurs where there is an inequality of the ship's attraction on the compass, for instance, where a com- pass is placed on one side or the other of the midship fore-and-aft line. Take the case of the steering compass when ' placed to one side of the steam steerer, the "one-sided" attraction, owing to the want of symmetry in the disposition of the mass. of iron comprising the appli- ance, catises a large inequality of attrac- tion on reverse points. compass is placed in the midship fore- and-aft line, if the iron around it is un- equally distributed the amount of the de- viation on reverse courses will not be the same. The principles of compass ad- justing presuppose that the same amount of attraction or deviation, exists on re- verse points. . : Note.--When speaking of the com- pass being affected and influenced by the ship's magnetism, it is to be understood that the compass is uncompensated, or not adjusted. The word "uncorrected" is sometimes used to denote the same thing. ae he WHEN THE CARD DOES NOT MOVE WITH THE SHIP'S HEAD. It is generally known among seamen that an unadjusted compass, in an iron or steel ship, does not, as the ship turns round, indicate the exact angle through which she has moved. Thus, in some directions of the shin's head, an actual movement through an angle of 20° may, according to the compass, be so little as 10°, or it may be so much as 30°; this difference, plus or minus, between the actual and apparent movement being in reality that portion of the total deviation which belongs to the particular angle, through which the ship has moved. WHAT THE COMPASS CARD IS SUPPOSED TO a DO. As we have already stated, the com- pass card is supposed to remain station- ary at all times; it appears to move, but this is only apparent, for it is the ship that turns beneath it. Where the com- pass has deviation (attraction) the card does not appear to move (but that is just when it does) for the attraction ap- pears to hold the card, but it really pulls Even where the. THE MARINE REVIEW it in the same direction that the boat turns in. If the boat is swinging to the right and the compass card does not ap- pear to move, but points out about the same direction, the deviation will be easterly, or to the right. Under the same conditions were the card to turn faster than the boat's head, the deviation will be westerly. The card must be turn- ing the opposite way from that of the boat. Note.--Another thing we wish to call attention to: The words vessel, ship, boat and steamer, are used indifferently to mean the same thing. QUESTIONS FOR MASTERS AND MATES.--NO.\ 31. 460. By an azimuth of the sun you find that the Dev. on correct magnetic north is 6 degrees Ely. amount of Dev. how should your com- pass read when steady on Frying Pan and Pipe Island ranges? 461. How should this same compass read on the Ecorse range, and also on the Texas Dock range? 462. Supposing your compass reads N34W on-Frying Pan and Pipe Is- land ranges, how much and which way is the deviation? 463. If your compass had 8 de- grees Wly. Dev. on correct magnetic NW how should it read when your boat is steady on Harwood Pt. range? 464. 465. If a compass is adjusted while a vessel is on an even beam and on an even keel, will the same adjustment an- swer with the ship not on an even keel? Why? 406. Will the same compass show the same readings or bearings with a. vessel light or loaded? Why? : 467. Why is it many times that the deviation on reverse courses in an un- adjusted compass is of a different amount? 468. Can -you: get a magnet that will adjust a point of. deviation on N. anda point-and-a-half on S?: Why? 469. If you were to adjust a com- pass on N and S, and you had an Ely. Dev. with the ship's head correct mag- netic north, which pole of the adjusting magnet would you place to starboard? 470. Name some ranges in the Sault river that are suitable for adjusting a compass on? 471. If you had %-pt. Ely. Dev. on correct magnetic east, how much,and which way would you expect to have it with ship's head correct magnetic west? 472. What is meant by semi-circu- lar deviation? Why is it so-called? 473. What is quadrantal deviation? With this - When is a vessel on an even: -beam? When is she on an even keel? Why is it called quadrantal deviation and what is the cause of same? 474. After the semi-circular devia- tion has been adjusted which way would you expect the deviation to be on NE correct magnetic? _ QUESTIONS FOR WHEELSMEN AND WATCHMEN.--NO. 32. 326. Give correct magnetic course and distance from a point one mile north of old Pt. Mackinae light to . North Manitou shoal gas buoy. 327. Give true course and distance from North Manitou shoal gas buoy to a point 4 miles north of Pt. Betsie lighthouse. 328. Give true course and distance from a point 4 miles north of Pt. Bet- sie lighthouse to Manitowoc harbor entrance. 329. Give true course and distance from a point 4 miles north of Pt. Bet- sie lighthouse to Sheboygan harbor en- trance, - 330. Give true course and distance from a point 4 miles north of Pt. Bet- sie lighthouse to Port Washington harbor entrance. ; 331. Give true course and distance from a point 4 miles north of Pt. Bet- sie lighthouse to Milwaukee harbor entrance, 332. Give true course: and distance from a point 4 miles north of Pt. Bet- sie lighthouse to Racine harbor en- trance. 333. Give true course and distance from a point 4 miles north of Pt. Bet- sie lighthouse to Kenosha harbor . en- trance. a ' 334. -Give true course and distance from a point 4 miles north of Pt. Bet- sie lighthouse to Waukegan harbor en- trance. 335. Give true course and distance from a point 4 miles north of Pt.. Bet- sie lighthouse to Chicago harbor en- trance. _ The foremen and officials of the Su- perior Ship Building Co. met socially on the evening of Feb. 7 at the Richelieu Hotel, Superior. In the unavoidable ab- sence of Sunt. Williams, Mr. John Law- son, head of the mechanical department, occupied the chair.. Mr. James Mac- Kellar, yard foreman, officiated as croup- ier. The speeches were along the line of furthering the work of the yard and helping various departments to work as a unit. The steamer Wilpen will be launched at the Ecorse yard. of the Great Lakes Engineering Works about March 23. Capt. Henry Peterson will bring her out and her chief engineer will be Wm. Riley.