Page:Philosophical Transactions - Volume 053.djvu/106

About the year 1720, a curvilinear sea chart made its appearance, said to be done by Henry Wilson, the publishers whereof represented Wright's chart as puzzling, difficult, and false.

But these groundless assertions were rationally answered by Mr. Thomas Haselden, afterwards master of the Royal Academy at Portsmouth, in a letter and pamphlet addressed to Dr. Halley about the year 1722.

In the year 1755 was published a book intitled, "The art of sailing upon the Sea", by W. E. which initial letters are sufficient to point out the ingenious author.—In page 74 he saies, "It is demonstrable (by the method of fluxions) that the length of the part of the meridian line in Mercator's chart, which represents the difference of latitude of two places upon the globe, is equal to the difference of the log. tangents of half the compliments of the two latitudes, multiplied into the number 2,30258509, and that product into the radius of the sphere".

And in Scholium to his Fundamental principles, page 75. "In the few foregoing propositions, I have demonstrated the truth of the chief methods of sailing now in use; and deduced them from their genuine principles, and fixt them upon their proper foundations: By which the reader will be enabled to see that this theory is not founded upon false principles; but upon such as are solid and true; and consequently that all calculations built hereon may be depended on as exact".

Notwithstanding these, Wright's method is charged with great imperfection by the late Mr. West of Exeter, in his posthumous work, referred unto byMr.