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

16 'Leon Locke, secretary, and their as- 'sociates on the executive committee of- the Interstate Inland Waterway Léague of Louisiana and Texas. QUESTIONS FOR MASTERS - - AND MATES.--NO.21. 1310. YOU are On" 'the course from Eagle Harbor to Whitefish Pt. The -weather is. thick and you figure that you. are about..10 miles from White- fish Pt.,.but you cannot hear the whis- tle. How would, you verify your#posi- tion by soundings? What soundings 'should you get if yua were to the eastward of your. course; what sound- ings and which kind of bottom should you get if you were to the westward of your course? -- 311. Can one depend upon the bearings taken of a fog oe in a heavy ORT Why? 312. Having obtained the bearing of a fog whistle during a 10g how would you verify your position? 23313; Inca. foe «Whitefish: Pt. fog whistle bears due south from you and -you figure that you are 4-miles (off, -how would you verify it? Supposing your patent sounding machine gave your depth at 38 fathoms, how far 'north of the point are you? » 814? In approaching .a -fog. signal from -windward where could you pick up the whistle coh aloft or on sdeck: : 315. Weoreachine a fog whistle ton leeward, where could you pick it. up earliest, on deck or Alois 316.; On the course from Pt.. Bet- "sey to Milwaukee in, thick weather, how. would you determine whether .you. were making. good this course? How . would you know. if you were fetching westerly of the course? When would you begin to use the Aead?. o ay. To give Sea aciy results in the performance of this work, - what 'instrument is necessary? ' 318. How do you know~ the speed of your boat in a fog? 319. You are running along in a 'fog on your natural gait. You give _your engineer a check whistle and he 'slows down, how do you know how fast your boat is running without a log? 320. Over a low lying fog you can see the steam rise from a fog signal 'but can see nothing else. Fifteen-sec- ond intervals elapse from the time e He. steam till you. get the the whistle, how far are you e. whistle? Can you judge your distance 321: from a fog signal by the power of the 'sound? Why is'it that many times cand -you could. not the. Pt: with moisture. THe MarRINE KEVIEW you can hear a fog whistle more dis- tinct at a given distance away than at a given distance that is not so far away? - 322. If you knew you' were in range of the sound of a fog whistle hear it, what would you lay the cause to? 323. From the echo of your own whistle, how could you determine ap- proximately your distance off a high shore bank in foggy weather, with little or no wind? 324. What extra precautions . do you take in a fog in the navigation of your boat? ANSWERS TO QUESTIONS FOR MASTERS AND MATES. NO. 21. 310. By taking chain of soundings and comparing them with the chart. To eastward of course would - get from 25 to 45-fathoms sand bottom. To westward and making in 11 to 7 fathoms, gravel and sand. Ten miles from. Whitefish would be about N from Crisps Point and would eget, if making in, soundings of 16 to 9 fathoms, making out 14 to 20, sand. ' 311.. No. The sound may. be in- fluenced by air currents and reach one by a circuitous route. Sound may be reflected from a nearby hill, an- other vessel, or a heavy fog bank. 312. By the depth of water and quality of the bottom. 313. By the lead; 38 fathoms from 3 to 4% miles N of the point. 314, Aloft. $15..On deck: ' 316. By taking soundings when about 15 miles from Milwaukee on Betsey coutse, should get 41° to 50 fathoms, blue clay. If mak- "ing 'to the westward, 35, 30, 20, 19, 13, "as you get closer inshore. lz. A good sounding machine. '316. By the log, or the. engine rev- "olutions. "319. Figure it out by proportion ac- cording to the engine revolutions. 320. Sound travels at the rate of 1125 ft. per second... 1,125X15 equals 16,875. 16,875 + 5,280 equals 3.1 stat- ute miles. 321. No. Wind may drive back the sound, or it may be rmtercepted by streams of air unequally saturated The sound may be weakened by repeated reflections, an air' current may carry it over the heads of persons near the signal and convey it to the hearing of persons at a greater distance. It is:not to be 'relied upon. 322. Wind, atéas of silence, or other atmospheric conditions that might render the sound inaudible. 323. Take the time in seconds be- tween the sound of the whistle and the echo and multiply by 1,125 and divide the result by two; the sound has to travel there and back. This is a very uncertain method, as the sound might be reflected from a fog bank, another vessel, or other nearby ob- ject. 324. Blow three blasts of the whis- tle at intervals of not less than one minute. On hearing the fog signal of another steamer not more than four points from right ahead, reduce speed to bare steerage way as required by law, keep additional lookout and in all respects navigate with caution. On approaching the shore or a turning point, use the lead at frequent inter- vals. THE TRADE WINDS. Most people have heard of the 'Trade. Winds," or. simply ---"The Trades,' as they are called by sailors, but it is probably not generally known what causes these winds and where they are found. It is easy to understand that a wind that is steady in force and constant in direction is of great benefit to sail- ing vessels, and it is from this ad- vantage to navigators--and hence to trade--that the trade winds take their - name. 'These winds are permanent over both the water and the land, prevail- ing in, and often beyond, the torrid zone. As the air within this zone re- ceives a greater amount of heat than the air outside, it rises, and its place is supplied by the cooler air which rushes in from the tropics. If, the earth. were at rest, it is evi- dent that a north wind would blow in the northern half. of the torrid zone, and a south wind in.the -south- ern half. But the earth, instead of being at rest, rotates on its axis from west to east. A little reflection « will enable 'any one to. understand that the greatest velocity resulting from iiis rotation must: be found. at: the equator, and that as one recedes from the. equator, the velocity diminishes until it reaches 'the poles, where it is nothing. The wind which 'is- rushing to the equator has continually a less velocity than that of the surface over which it passes, and so falls behind more and: more as the equator is -ap- proached. This gives it a direction opposite to the earth's 'rotation, in other words, a direction from the east to the west, which, combined with the motion from:the north and: south, before mentioned, gives as a result