_B._ I find first (p. 4), that the grounds of his argument are the two observations made by Mr. Burroughs, one at Vaygates, in 1576, where the variation from the pole of the earth he found to be 11 deg. 15 min. east; the other at Limehouse, near London, in 1580, where the variation from the pole of the earth was 8 deg. 38 min. west, by which, he saith, he might _find out the magnetical pole_. _A._ Where is Vaygates? _B._ In 70 degrees of north latitude; the difference of longitude between London and it being 58 degrees. _A._ The longitude of places being yet to seek, how came he to know this difference of 58 degrees, except the poles of the magnet and the earth be the same? _B._ I believe he trusted to the globe for that. For the distance between the places is not above 2000 miles the nearest way. But we will pass by that, and come to his demonstration, and to his diagram, wherein L is London, P the north-pole of the earth, V Vaygates. So that L P is 38 deg. 28 min.; P V 20 deg.; the angle L P V 58 deg. for the difference between the longitudes of Vaygates and London. This is the construction. But before I come to the demonstration, I have an inference to draw from these observations, which is this. Because in the same year the variation at London was 11 deg. 15 min. east, and at Vaygates 8 deg. 38 min. west; if you subtract 11 deg. 15 min. from the arc L P; and 8 deg. 38 min. from the arc L V, the variation on both sides will be taken away; so that P V being the meridian of Vaygates, and L P the meridian of London, they shall both of them meet in P the pole of the earth. And if the pole of the magnet be nearer to the zenith of London than is the pole of the earth, it shall be just as much nearer to the zenith of Vaygates in the meridian of Vaygates, which is P V; as is manifest by the diurnal motion of the earth. _A._ All this I conceive without difficulty. Proceed to the demonstration. _B._ Mark well now. His words are these (page 5): From P L V subtract 11 deg. 15 min., and there remains the angle V L M. Consider now which is the angle P L V, and which is the remaining angle V L M, and tell what you understand by it. _A._ He has marked the angle P L V with two numbers, 11 deg. 15 min. and 21 deg. 50 min., which together make 33 deg. 5 min. And the angle 11 deg. 15 min. being subtracted from P L V, there will remain 21 deg. 50 min. for the angle V L M. I know not what to say to it. For I thought the arc P V, which is 20 deg., had been the arc of the spherical angle P L V; and that the arc L V had been 58 deg., because he says the angle L P V is so; and that the arc L M had been 46 deg., because the angle L P M is so; and lastly, that the angle P L M had been 8 deg. 30 min., because the arc P M is so.