[s. H. DAWSON] THE LINES OF DEMARCATION 493 



jectnre amounts to certainty that Colnmbns indicated the line of one 

 hundred leagues west of the Azores as a natural and equitable boundary. 

 There was, as pointed out by Humboldt, a reasonable motive "for seek- 

 " ing to eonvei-t a physical into n political boundary line.'' He be- 

 lieved that lines of variation ran parallel to the meridians ; for on his 

 return from his second voyage, when the pilots, by reason of severe 

 storms, had lost their reckoning, he thought in that way to lascertain 

 his longitude. Mr. Harrisse is doubtless right in maintaining that 

 Portugal had no share in fixing the line of one hundred leagues. Fer- 

 nan Columbus said that his father had suggested the line and everything 

 points that way. In the charter of privileges to the admiral the mon- 

 archs call it "the line which we have caused to be traced." The Spanish 

 envoys were instructed to inform the Pope that the discoveries had 

 been made without encroaching on the possessions confirmed to Portu- 

 gal. In view of the existing treaty between the two crowns and the 

 IjuIIs granted at the instance of Portugal the request of Spain was 

 politic and re'asonable and it was urged with promptness and vigour. 



The line fixed by Alexander VI. was therefore a scientific line ; 

 based upon the very first observation ever made of magnetic variation, 

 and to cite Humboldt^" again, " the Pope actually rendered, without 

 " knowing it, an essential service to nautical astronomy and the physical 

 "' science of terrestrial magnetism." By directing attention to this new 

 fact he gave a stimulus to continued investigation. He was, therefore, 

 abreast with the latest physical discovery of his day, and he was ahead of 

 many, who during the Gal)ot discussions of the last few years, have been 

 tracing imaginary courses over the ocean while ignoring the prime factor 

 of terrestrial magnetism. 



Upon careful reading there does not appear to be any vagueness 

 of language in the Bull. The Pope evidently distinguished between 

 what he knew and what he did not know. He stated the distance west- 

 ward in leagues — a measure of length absolute in itself and familiar to 

 all mariners. He did not attempt to decide the circumference of the 

 earth or to fix the length of a degree. He and his officials had too keen 

 a sense of logic to regulate the length of a league, which was a kno^vn 

 and certain quantity, by the specul'ative length of a degree which was 

 an unknown and uncertain quantity. He did not, moreover, attempt 

 to fix the latitude and longitude of the Azores or Cape Verde Islands. 

 He was content to leave them wherever they might be and to measure 

 westwards in a definite direction with a definite measure from a definite 

 point — to wit, the most westward of either of the two groups of islands 

 in the Atlantic then held by right of discovery as possessions of 

 Portugal. 



