John Churchman, THE MAGNETIC ATLAS, OR VARIATION CHARTS OF THE WHOLE TERRAQUEOUS GLOVE: COMPRISING A SYSTEM OF THE VARIATION & DIP OF THE NEEDLE, BY WHICH THE OBSERVATIONS BEING TRULY MADE, The Longitude MAY BE ASCERTAINED. THE THIRD EDITION WITH ADDITIONS.

A very rare third edition of The Magnetic Atlas, “printed for the author, and sold by Gaine & Ten Eyck, No. 148, Pearl-Street” in New York. In fact, close comparison indicates that it was assembled from remaindered sheets of the 1794 London edition, with the substitution of a new title leaf, the addition of two leaves of notes after the Appendix (pp. 77-80), and the substitution of a new list of subscribers at the end (These sheets are on different stock and noticeably smaller than those printed in London.) The text begins with a long “History of Magnetic Discoveries,” followed by a short chapter of “Definitions and Corollaries,” chapters explaining the construction and use of the Magnetic Atlas, and a chapter speculating on the causes and effects of magnetic variation. These are followed by an Appendix reprinting correspondence that constitutes, if not an unalloyed endorsement of Churchman’s work, then at least a cautious recommendation thereof. The volume concludes with a short list of merely 51 subscribers, among them Aaron Burr of New York. The list is a far cry from the nearly 300 subscribers to the first edition, which had including representatives of America’s political, intellectual, religious and business elite, among them Adams, Jefferson, Hamilton and Franklin.
The pamphlet is illustrated by three plates, including two large folding maps depicting the northern and southern hemispheres on a polar projection. Each consists of eleven gores, which if assembled would yield a globe approximately 48” in circumference. On the map of the Northern Hemisphere the north “Magnetic Point,” or Pole, is shown at its supposed location in the Canadian Arctic, with the “Magnetic Orbit” a concentric ring around the geographic North Pole (Due to the lack of observations in the region, the location of the southern “Magnetic Point” is left imprecise.) Latitude and longitude are indicated by solid lines at one-degree intervals, while “magnetic meridians” emanate from the Magnetic Point as dotted lines intersecting the geographical meridians at angles corresponding to the magnetic variation. Though rather beside the point, the geography itself is relatively up to date and includes for example a reasonable depiction of the northern Pacific and Australia.
As with the text, close comparison indicates that these maps were printed from the same plates as those used for the London edition. However, the London imprint has been removed and the date changed to “1st July 1800, and numbers added to indicate compass variation along the magnetic meridians. These changes are in a different hand than that of the original engraver, but it is not known whether they were executed in London or New York.
This third edition of the Magnetic Atlas is extremely rare. Rare Book Hublists no copies having appeared on the antiquarian market, while between them ESTC and OCLC locate but eight institutional holdings, of which only two are here in the United States (Boston Public Library and Princeton).
The fate of the Magnetic Atlas
Churchman’s correspondence with the Board of Longitude endured from 1787 through 1804 and is preserved to this day at the Royal Greenwich Observatory. Predictably, given the gaping flaws in this theories and methods, the Board never provided him the recognition he felt he deserved.
“Churchman must rank as the most persistent of all the investigators who studied the problem of finding longitude by variation: he devoted sustained attention to the problem for a period of at least seventeen years, and was encouraged to do so by many eminent men of science at the time. Yet his efforts were, from the outset, doomed to failure, and the Board of Longitude at no time seemed to be willing to grant him financial support…” (Cotter, 218)
Churchman does seem to have received considerable recognition elsewhere. The U.S. Congress repeatedly passed resolutions expressing strong approbation, though it rejected his petition for funding for a voyage to Baffin Bay to gather evidence confirming his theories. He received encouraging correspondence from as far afield as France, Germany and Russia, and in 1796 was even elected a member of the Imperial Academy of Sciences at St. Petersburg—an honor carefully noted on the title page of the present volume. However, reading between the lines one receives the strong impression that he was ultimately frustrated by the lack of financial recognition from either Congress or the Board of Longitude.
From Daniel Crouch