34 Mifcellanea Curio fa. 



one place the Needle varies zg^ Degrees to 

 the Wefl ; at the other zol Degrees to the Eafi. 

 This plainly demonftrates the impossibility of' 

 reconciling thefe Variations by the Theory of 

 Bond', which is by two Magnetical Poles and an 

 Axis 7 -inclind to the Axis of the Earth j from 

 whence it would follow, That under the fame 

 Meridian the Variation fhould be in all places the 

 fame way* 



Thefe things being premifed may ferve as a. 

 fure Foundation to raife the Superftru&ure of a 

 Theory upon. But firft it would not be amifs 

 to (hew hereby the miftake of Gilbert and Des 

 Cartes : The firft whereof fuppofes ; that the 

 Earth it felf being in all its parts Magnetical^ and 

 the Water not ; wherefoever the Land is, thither 

 alfo (hould the Needle turn, as to the greater quan- 

 tity of Magnetical Matter. But this in many In- 

 ftances is not true ; but moft remarkably up- 

 on the Coaft of Bra%ile 9 where the Needle is 

 lb far from being attracted by the Land, that 

 at turns the quite contrary way, leaving the 

 Meridian to lye N b E, which is juft along the 

 Coaft. As to the Pofition of Des Cartes, that 

 the Iron and Load ft ones hid in tbe Bowels of the 

 Earth and the Bottom of the Sea, may be the Caufes 

 that the Needle varies j if we confider for how 

 great a part of the Earths Surface, ex gr. in the 

 whole Indian Sea, the Needle declines the fame 

 way, and that regularly, 'twill follow that the 

 attracting Sabftance that occafions it, muft be 

 very far diftant. Now by Experience we find 

 the little force that Iron Guns have upon the 

 Compafs in Ships (their Vertue, though they 

 be Demiculverin, or greater Cannon, being not 

 perceptible at four or five Yards diftance) and 



