_Yten_: In order that the said line or bound of the said division may be made straight and as nearly as possible the said distance of three hundred and seventy leagues west of the Cabo Verde islands, as hereinbefore stated, the said representatives of both the said parties agree and assent that within the ten months immediately following the date of this treaty, their said constituent lords shall despatch two or four caravels, namely, one or two by each one of them, a greater or less number, as they may mutually consider necessary. These vessels shall meet at the island of Grande Canaria [Grand Canary Island] during this time, and each one of the said parties shall send certain persons in them, to wit, pilots, astrologers, sailors, and any others they may deem desirable. But there must be as many on one side as on the other, and certain of the said pilots, astrologers, sailors, and others of those sent by the said King and Queen of Castilla, Aragon, etc., and who are experienced, shall embark in the ships of the said King of Portugal and the Algarbes; in like manner certain of the said persons sent by the said King of Portugal shall embark in the ship or ships of the said King and Queen of Castilla, Aragon, etc.: a like number in each case, so that they may jointly study and examine to better advantage the sea, courses, winds, and the degrees of the sun or of north latitude, [162] and lay out the leagues aforesaid, in order that, in determining the line and boundary, all sent and empowered by both the said parties in the said vessels, shall jointly concur. These said vessels shall continue their course together to the said Cabo Verde islands, from whence they shall lay a direct course to the west, to the distance of the said three hundred and seventy degrees, measured as the said persons shall agree, and measured without prejudice to the said parts. When this point is reached, such point will constitute the place and mark for measuring degrees of the sun or of north latitude either by daily runs measured in leagues, or in any other manner that shall mutually be deemed better. This said line shall be drawn north and south as aforesaid, from the said Arctic pole to the said Antarctic pole. And when this line has been determined as above said, those sent by each of the aforesaid parties, to whom each one of the said parties must delegate his own authority and power, to determine the said mark and bound, shall draw up a writing concerning it and affix thereto their signatures. And when determined by the mutual consent of all of them, this line shall be considered forever as a perpetual mark and bound, in such wise that the said parties, or either of them, or their future successors, shall be unable to deny it, or erase or remove it, at any time or in any manner whatsoever. And should, perchance, the said line and bound from pole to pole, as aforesaid, intersect any island or mainland,