Philada 7 June, 1787
Mr. John Churchman of This City Thinks he has discover’d a Method by Which the longitude at Sea or Land may be Ascertain’d by one simple Observation in Any part of The World, & Which is Certainly Very Easy if the Great fact on Which the whole depends can be well Ascertain’d & Which I think not Improbable, tis this. Viz that the Magneetic needle has two poles, one <
North> 13° 56’ from the N. Pole of the Earth the other South abt. 18° from the S. Pole of the Earth, Which Poles have a Constant Rotation from West to East, & form their revolutions in 463 Years, & 344 days i.e. abt. 47’ Minutes of a degree in a Year, that the True place of these poles may be Ascertain’d, & Tables of the Same calculated for Every Given Minute of Time, & ofCourse that the line or point of no Variation for any place & the Time, may be Easily [found] & ofCourse the Angle of Variation & radius will always be attainable, & the Difference of Latitude of the place of Observation & that of the Magnetic pole will be one Side of the Triangle [Necessary] to be found,—he farther tells me that by a Long attention to Halley’s Theory of the Magnet, & the various Observations of Cook and many other Navigators in their Very Long Voiages, & by comparing them all together, it Appears that the Line< s> of Variation When continued, on the Globe from whatever part of the Earth never fail to Meet at the same place or point Where the pole of the Magnet by his Tables was found to be at the time of Observation,—This is A Matter of Such Mighty consequence, & the Truth or falsehood of his plan or Method may be So Easily Examin’d that I think it will worth a Very Careful Attention & Enquiry, & the Author is Undoubtedly invited to the honours & Rewards of the Discovery, if his Great fail is found True on Sufficient proof. Mr Churchman is a Young Man of Good Character, of a Good Country Education but Not a Genl. Acquaintance with any Course of Liberal Learning, At his Desire I hereby Recomend him & his plan (wc. he Sends to You,) to Your favorable Notice & Patronage—I have Nothing New or Important to inform You but the Convention of the States are now Sitting here, with a view to mind Our Articles of Confederation or form a New System, Which perhaps is Much Easier of the Two, but how they will Succeed God Knows our Consessions are Very Great.
I have the honour to be / Hond. Sir, / with all Esteem & Respect / Your Most obt. / & very hume servt.
MHi: Adams Papers.