224 



THE NATIONAL GEOGRAPHIC MAGAZINE 



of discovering them ? There is only one 

 non-magnetic vessel afloat, and that is 

 the Carnegie, and the 'magnetic' vessels 

 seem to have got along very well in spite 

 of the errors." 



This clipping is interesting from vari- 

 ous points of view and serves splendidly 

 as a text for what we have to say. The 

 pardonable misapprehension of the re- 

 porter as to the purpose of mapping out 

 the earth's magnetic forces, as accurately 

 as possible, gives point to the following 

 quotation from Thomas Hood's amusing 

 essay on "The Ocean" : 



"The importance of the mariner's 

 compass to the sailor is as well known 

 universally as the utility of the little one- 

 eyed instrument, for w^hich Whitechapel 

 is so famous, to the tailor: but its mode 

 of action and the manner of application 

 must be far less generally understood." 



Hood draws the comparison here be- 

 tween the tailor's one-eyed instrument 

 and the compass needle which, because 

 of its antics and "variations," gave the 

 sailors "stitches." And he says : 



"The needles have sometimes been 

 fatal to mariners." 



At the time of the launching of the 

 Carnegie, on June 12, 1909, accounts and 

 explanations of the unique features of 

 this, the most "unattractive" craft afloat, 

 as one paper put it, appeared in news- 

 papers and periodicals, not only in all 

 parts of our own country, but in all civil- 

 ized regions of the globe. Since then 

 clippings are received almost daily with 

 respect to the work done by the vessel. 

 In view of this wide-spread interest, I 

 have accepted with much pleasure the 

 invitation of the editor of the National 

 Geographic Magazine to describe, in 

 untechnical language, the Carnegie's 

 work, and to set forth the purposes of 

 her mission. 



Let me say first that the name of the 

 institution under which the Carnegie is 

 operating is the "Carnegie Institution of 

 Washington," not the "Carnegie Insti- 

 tute," as the reporter has it. The latter 

 is located in Pittsburg, and is an entirely 

 different organization. 



HOW DO WE TELL THE NORTH? 



From early childhood we are taught 

 that, if we face the north, then our right 

 hand is pointing eastward. But suppose 

 we were suddenly transplanted to a re- 

 gion utterly unknown to us, and where 

 a dense cloud covered the sun by day 

 and the stars and moon by night. How 

 could we tell then which direction was 

 northward? This is precisely the prob- 

 lem the mariner has set before him on 

 the trackless seas when the skies are 

 overcast with heavy clouds, completely 

 shutting out all view of celestial bodies. 



Fortunately there is one natural, 

 agency — independent of wind and 

 weather, night or day — which comes to- 

 our rescue, and upon which the naviga- 

 tor, in spite of its so-called "fickleness,"" 

 has come to rely, namely, the earth's- 

 magnetism, by whose subtle power a defi- 

 nite direction is imparted to a delicately^ 

 poised magnetized bit of steel. Take a 

 compass needle, such as can readily be 

 purchased for a mere trifle and is often, 

 found inserted in watch charms ; hold it 

 on the table, where it will not be exposed 

 to jarring. When the needle has come to- 

 rest, note its direction, then draw it aside 

 by bringing sufficiently close to it a. 

 pocket knife or any other article of iron 

 or steel ; next, quickly remove the article. 

 The needle swings back and forth, first 

 through a large arc and then through a. 

 gradually diminishing one, until finally 

 it comes to rest ; if the proper precau- 

 tions have been taken this position will- 

 be found identical with the first. Repeat 

 the experiment and once more, after 

 various oscillations back and forth, the 

 needle settles down to the same direction 

 as before. Why is this? 



Sir Isaac Newton, from seeing the 

 apple drop, concluded that the cause of 

 this "phenomenon" was to be referred to 

 the "force of gravitation" : the earth 

 "attracted" to itself the apple. And were 

 we to suspend a heavy mass, from the 

 ceiling, let us say, it will hang in an 

 invariable direction — the vertical, or that 

 shown by the plumb-line. Draw the 

 mass aside, then release it. It swings. 



