THE CONQUEST OF THE ZONES 



"Pillars of Hercules" and discovered at the very con- 

 fines of the world what we now term the British Isles. 

 But this was the full extent of exploration throughout 

 antiquity; and the spread of civilization about the 

 borders of the known world was a slow and haphazard 

 procedure during all those centuries that mark the 

 Classical and Byzantine periods. 



THE mariner's COMPASS 



The change came with that revival of scientific 

 learning which was to usher in the new era that we speak 

 of as modem times. And here as always it was a 

 practical mechanism that gave the stimulus to new 

 endeavor. In this particular case the implement in 

 question was the mariner's compass, which consists, 

 in its essentials, as everyone is aware, of a magnetized 

 needle floated or suspended in such a way that it is 

 made under the influence of terrestrial magnetism to 

 point to the north and south. 



The mysterious property whereby the magnetized 

 needle obeys this inscrutable impulse is, in the last 

 analysis, inexplicable even to the science of our day. 

 But the facts, in their cruder relations, had been familiar 

 from time immemorial to a nation whose habitat lay 

 beyond the ken of the classical world — namely, the 

 Chinese. It seems to be fairly established that naviga- 

 tors of that nation had used the magnetized needle, 

 so arranged as to constitute a crude compass, from a 

 period possibly antedating the Christian Era. To 

 Western nations, however, the properties of the magna- 



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