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also between white and green, there is always a small arc of uncertain color, When looking out for a light at night, the fact is sometimes forgotten that from aloft the range of vision is much in- creased. By noting a star immediately over the light, a very correct bearing may be obtained from the standard compass before the light becomes visible to those on deck. The range of Twin River Pt. light at an elevation of the eye at 15 ft. is given at 19 miles, but this light has been ob- served six miles from the Sturgeon Bay canal. The observer's eye in this case was oe 29-6 it. above the' lake. This would give it a range of 20.5 miles, But in the case ~ just stated its range was about 34 miles. There is a vast difference between 20.5 and 34 miles, and in many cases a departure, based upon such incorrect data, would lead to eet, fake the Sturgeon. Bay Canal light, which has a range of 18% miles, has been seen in a run of 30 minutes (about five miles) out of Frankfort; that is, steering for the canal from Frankfort this light has been picked up five miles outside of Frankfort on the canal course. The distance from Frankfort to the canal is 53 miles, thus the light was seen 48 miles, or it appeared to be seen at that distance. Of course, in both cases ab- normal refraction has temporarily lifted these lights above the horizon, and made them visible at a point, where, under or- dinary conditions, such a thing would be impossible. The reverse of this phenome- non occasionally happens. In the case of the canal light the red flash could not be seen for a long time after the white flash was first seen. The atmosphere at the time was cold and clear, and one could almost see the refraction in the air. The Stars shone with marked brilliancy, espe- cially near the horizon, where, of course, the refraction was greatest. There are many cases where lights have been seen beyond the range of visibility, and the Tange held for a certain time, and then lost for a long time, notwithstanding that the vessel was approaching the light all the time. This is due to some atmospheric _ change, which caused it to vanish. There fe times when a vessel steadily ap- Proaching a light will not be able to see it until inside the ordinary range of visi- bility, and this will happen in clear Weather, which all goes to show the ef- fects and freaks of refraction. __ Mariners in mid-lake have seen. the lights of Big Point Sable, Twin River Pt. 'nd the Sturgeon Bay canal all at the 'ame time, They were in about the cen- (Of the group, a radius of 32 miles, uch, in this, case, was the range of The ordinary range of these lights out 19 miles, he sand bluff (the third in height) 'TAE Marine REVIEW about three miles north of Arcadia, east shore of Lake Michigan, is elevated 400 ft. above the lake. If from the height of your eye in standing on the bridge, it was 20 ft. to the water, and in crossing the. lake under ordinary conditions, at what distance should you seé the top of this bluff above the horizon? Answer, 32 1/3 miles. The two bluffs between this one and Arcadia are, the one 180 ft., the other 69 ft. The bluff about 214 miles south of Frankfort has an elevation of 300 Et; and the one at South Frankfort is 265 it. the one back of Frankfort, on the north side, 120 ft. and the one just north of Frankfort pierhead is 323 ft. above the lake. Work each one of these out and sée what their ranges are. When the tops of these bluffs are picked up in mid-lake they resemble small islands. Here's another wrinkle worth knowing: Having ascertained by the range tables the distance that you are from a light when it first comes in view, take its bear- ing and see what the angle is between it and the course you are steering; and to ~ determine the approximate distance at which the latter will be passed abeam, provided always that the same course be steered and made good, proceed as fol- lows: Seek in the tables of hypotenuse, perpendicular, and base, with the angle between the course and light and with the distance in the hypotenuse column op- posite it, in the base column will be found the passing distance required; and that shown against it in the perpendicular column will be the distance that the ves- sel will have to run in order to get the light abeam. Example--You are steering S by E by compass, and at the first appearance of Grosse Point light, its bearing is taken as S %4 W, and its range calculated at 19 miles. Seek in the table for angle of 114 points (which is the difference be- - tween course and: bearing) and with 19 in the hypotenuse column opposite it in the base column will be found 5.5 miles, the distance that she will be from the light when she has it on her beam; and in the perpendicular column will be found 18.2, the number of miles that the ves- sel is required to steam in order to bring the light abeam. : Remember what has been said about this method, and the check to be used, as it only gives approximate results. Bear in mind that current, leeway, or bad steering, is apt to have a finger in the pie: : In the case of the ship knowing her actual distance from a light or other ob- ject (found by cross bearings, or ee wise) then the akove method noe 2 beaten for quick and accurate work; - all that is required is to know the dis- gle, and the remainder of ou get tance and an ; ihe data necessary for its solution y 2? out of the tables. If the distance as found from the tables is going to carry the vessel in or out more than is desired, the course can be altered accordingly, and likewise, the correct amount of -change can be got from these same tables. For example: Supposing that you were 13 miles from a light and its bearing was two points from the course. In table under angle of two points and distance 13 in hypotenuse column gives against it in base column five, the number of miles that the vessel will be off when abreast of the light; but supposing that you de- sired to be only three miles off when abreast, how much have you got to haul her in? Even this information can be found from these tables: Seek in the tables and find the angle where 13.in the hypotenuse column agrees with two (5 -- 3 = 2) in the base column, and this will be the required amount to haul her in. In the above case it will be found under _ angle 34 point. Pretty handy, isn't it? QUESTIONS FOR WHEELSMEN AND WATCHMEN, 489. It takes you 3 hours 45 minutes' to run from Cleveland to SE shoal, 4234 miles, how fast are you running per hour? me 490. Your boat makes 10% miles per hour, how long will it take her to cover the above distance? : 491. How many marks between 6 fath- oms and 16 fathoms on the lead line? 492. How many marks on the lead line between 18 and 20 fathoms? 493. What point on the compass: is N 270 degrees E? 494. How many degrees is NW to the fight of north? 495. You have a variation of 42 min- utes, how much would you allow in points on the compass? 496. Supposing the variation were 43 minutes, how much would you allow? 497. Is 2 degrees 7 minutes nearer to Ye-pt. or %4-pt.? 498. What point on the compass is 225 degrees to the right of N? 499. How many degrees in 7p-pt.? ANSWERS TO QUESTIONS FOR WHEELSMEN AND WATCH- MEN. 478. 2.5125 hours. 479. 3.3 miles. : 480. 5.5 minutes to make a mile, and is running 10.9 miles an hour. 481. 734 minutes. -- 482. 12.69 hours, or 12 hours 62 min- utes, nearly. : ics 483, SW 6 Wabts buosse a cet) 484. We 1% S 8514 -milesz! 9 v0) 30: 485. 10.17 -miless'o: + : ai: 486. ENE. 487. West. 488. W by N.