The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

even though they are situated near to each other. In vessels wholly constructed of iron or steel there is a continual and powerful magnetic force, and as we have already learned, if the compass is placed near a mass of iron or steel, - the compass needle will be attracted or repelled. by it,' depending on the position of its poles and that of the compass needle. The. deviation thus caused could readily be conquered if it a = ee a eee FIGS Position of greatest deflection. Dev. i Ship's head east correct magnetic, but ENE.by- compass. is Ely. because the needle (or card) is drawn to the right of its proper place, the attraction "TAE. MARINE. REVIEW in mind that the magnetism in the said mass of hard iron is of a fixed or per- manent quantity, it having acquired its polarity by remaining in the magnetic meridian of a northern latitude (head+ ing north) for a long périod of 'time. When ~the vessel is steering' north magnetic the compass will have its north and south points in line with' the mass of iron and as the south pole of the mass of iron is nearest to 'the' north pole of the compass needle' there (the disturbing force) of the mass of iron, with its permanent magnetism, being responsible for it: ° To steer east correct magnetic the ship would have to steer E PES compass the ship would be making a correct magnetic course of From a correct magnetic course to a compass course Ely. 2-pts.. to the left of E is ENE. From compass course to correct magnetic course Ely. Dev. If the compass course: is E with BptsO Ky.) Dev.; east. lowed to the right. is 2-pts. to the right of east, or ESE. by compass. To steer east by is allowed to the lefts. and is al= the correct: magnetic - course Dev. 101 A in each of the above figures is a mass) as iron, of. permanent* magnetism "whose minenete 33 by means of a magnet, or piece of steel or iron sufficiently magnetic for the "purpose, and set the needle to vibrat- ing; remove the magnet quickly; now mark the time to the nearest fractional part of a second required by the needle (north on the card) to make ten com- plete vibrations acfoss the lubber's mark, and we will say that it took 10 'through the same process ~and in a similar manner; you can read- seconds of time--one vibration for each second. Now imagine this mass 'of tron put back into position on the vessel as it was before and then set the: compass... .to vibrating. and go as above ily see that the compass needle will swing or vibrate faster with 'this in- "crease of magnetism due to the mass of iron; before it was only the earth's magnetism that influenced it, now it is both the earth and the mass of iron. It will now probably only take 6 or 8 sec- 'onds for the needle to make the 10 vibrations, Do you now see -what is meant by the directive force? This test is a method employed by experts 'in' discovering any imperfection in the The-. wo or less points to the south of ° poles are developed according to the way they dre lettered--S heing ;the S-pole, and N. the N-pole. .. Remember that the deviation of the 'eompass: is the angle between the magnetic meridian and the direction of the compass: needle, or north and south on the card, and represents the effect of the distutbing force of iron near it. The disturbing force may be either an attraction, It is Convenient to regard it always as an attractive force. : the other end must be repelled. ora repulsion. pass needle is attracted, If one end of a com-:' Since the name of the deviation de- _ pends on the way the card is deflected it matters not whether the deflection is caused by an at- traction or a repulsion, so Jong as the eeren taken by the card is known. . it of were constant, but instead of - that, changes on nearly every change' reading of the compass, that is, when- ever, the vessel's course is changed the deviation changes, and it is seldom the same on any two 'points of the com- pass. not always regular. will presently see. :_ For an example, let us suppose the case of a wooden vessel (the same one we had in 'the' lesson on Var.,'1.e., without.a- particle of iron in her. con- struction or equipment) in which a mass of hard iron (already polarized by the earth' Ss inductive force) situated a short. distance in front, and directly in line,. and about on a level with the steering compass (see Fig. 1.) Bear ee this is .we This change in the deviation is . is an attraction; but there can be no _ deflection, or change in the direction of the needle to one side or the other because the attraction is in the same | is © line -with the compass needle. It afact, though, that the directive force of the needle is increased by the at- tractive force of this-mass of iron, that. Hf is, in addition to the earth's magnetic | pe force, which gives, the needle the pow- er of pointing, the needle is inflnenced . just that, much more by fhe mass of 'Here is another way of. explain~. iron. ing it, suppose this mass of iron out of the ship, and nothing to influence the compass needle except the earth's magnetism; the compass | reads north, now imagine "the CSapade sHeedle "drawn aside from its' position of rest' ~ born in a little Ohio town. workings of the compass. | MR. GEORGE P. FREEMAN. George P. Freeman, of the W. Bing- ham Co., claims the distinction of hav- *"MR. GEORGE P.:' FREEMAN. ing voted in the same house he was - Mr. Free- man at one time sailed on the lakes, but he enjoyed being a landlubber' bet- ter and for many years he has been a | hardware man. Mr. Freeman has many friends in the rank and file of marine mien,