VOYAGES OF TIIK CABOTS IN 1497 AND 1498. 9S 



to tho public concerning things which had never before been described or discovered so exactly, for 

 although in years past some one may have written about them, it was trifling in compai-ison with what 

 we have discovered in tho last ten years." '* 



Champlain's Notes on this Map. 



" 1 have made this map for the convenience of the majority of those who sail on these coasts, for 

 many use compa.sses set for the hemisphere of Asia, 133^ which they navigate. If I had made this map 

 like the small one, most sailoi's would have been unable to uno it, through being unacquainted with 

 the variations of the needle." 



"Note that on this map north-northeast stands for north, and west-northwest for west; this will 

 help you to get the elevations of the degrees of latitude as if it were the true east and west and north 

 and south ; inasmuch as the said map is made on the compass of France set to northeast." 



APPENDIX B. 



Variation op the Compass. 



The fact of the variation of the compass having once been observed it occurred to Columbus to 

 use it as a means of determining longitudes at sea. In those days dead reckoning was the only 

 method known and, while the latitudes of old maps are fairly correct, the longitudes are far, ofteti 

 absurdly far, astray. The log line was not used until after Magellan's voyage in A.D. 1521, and the 

 speed of sailing was estimated by the eye with the aid of a half-hour sand-glass. In his second 

 voyage, Columbus attempted to put to practical use his observations upon the variation of the needle, 

 and Sebastian Cabot was all his lifetime haunted by a similar idea. He is erroneously supposed by 

 many to have first observed the variation and he seems to have claimed it (see p. 64). Livio Sanuto 

 (Geografia Distinta, Venice, 1588) states that he was informed by Sebastian Cabot that the point 

 of no variation was 110 miles to the westward of the meridian of Flores. The latitude is not recorded 

 but it was probably 46° north. Cabot told the Venetian ambassador to Spain (Contarinij that he 

 alone knew of a way to determine longitude by variation. The same idea is met in Champlain's 

 voyages, and, in the " Arcano del Mare," a method is proposed for the purpose. The line of demarcation 

 drawn by the bull of Alexander VI. was a meridian 100 leagues west of the Azores, and the idea that 

 the needle changed to the west at that point h.ad an influence in fixing the line, but not long after, by 

 the treaty of Tordesillas, the line was, for other reasons, moved to a meridian 370 leagues west of the 

 Cape de Verde islands. Longitude was for a long time calculated from Pico, an island in tho Azores 

 28° 28' west from Greenwich. Captain .John D.ivis (in his " Seamen's Secrets," London, 1C07,) says 

 that longitude was calculated from St. Michael's, one of the Azores as the meridian of no variation 

 and English sailors continued to reckon from that point until the establishment of Greenwich obser- 

 vatory. On the latest charts the point of no variation is at 24° west. 



Euysch, who made the map in the Ptolemy of 1508, (see p. 75) the first engraved map showing 

 America, sailed on one of the earliest voj'ages to the northeast coast of the new world. He was pro- 

 bably on the second Cabot voyage, and a note upon his map indicates some exti'aordinary experience 

 on the north of Labrador, '' Here a raging sea begins ; here the compasses of the ships do not retain 

 " their properties and ships having iron are not able to return." He must have been near the 

 magnetic pole of that era.'' The great problem among sailors and maritime nations then and for 

 two hundred years later was to find a method of determining longitude. Large standing rewards 

 were instituted by Philip II. and by the state of Holland for the discovery of that secret. 



