Page 288

An.1686

Of the Breadth of the South Sea.

shewed it to be so near the same, but decreasing : Neither did we observe it at Guam, for Captain Swan who had the Instruments in his Cabbin, did not seem much to regard it: Yet I am inclined to think that at Guam, the Variation might be either none at all, or even increasing to the Westward.

To conclude, May 20th at noon (when we begin to call it 21st) we were in lat. 12 d. 50 m. N. by R. having run since the noon before 134 miles direct- ly West. We continued the same course till 2 that afternoon, for which I allow 10 miles more, West still, and then, finding the parallel we ran up- on to be too much Southerly, we clapt on a Wind and failed directly North, till 5 in the afternoon, having in that time run 8 mile, and increased our latitude so many minutes, making it 12 d. 58 m. We then saw the Island Guam bearing N. N. E. di- stant from us about 8 leagues, which gives the latitude of the Island 13. d. 20 m. And according to the account foregoing, its longitude is 125 d. 11 m. West from Cape Corrientes on the Coast of Mexico, allowing 58 and 59 Italian miles to a degree in these latitudes, at the common rate of 60 miles to a degree of the Equator, as before computed.

As a Corollary from hence it will follow, that upon a supposal of the truth of the general al- lowance, Seamen make of 60 Italian miles to an Equinoctial degree, that the South Sea must be of a greater breadth by 25 degrees, than it s commonly reckoned by Hydrographers, who makes it only a- bout 100, more or less. For since we found (as I shall have occasion to say) the distance from Guam to the Eastern parts of Asia, to be much the same with the common reckoning; it follows by way of necessary consequence from hence, that the 25 degrees of longitude, or thereabouts, which are un- der-reckon'd in the distance between America and the East Indies Westward, must be over-reckoned in