The following paragraphs are from a transcript of a letter that John Vaughan (1756-1841), the librarian and treasurer of the American Philosophical Society, received from Nicholas Biddle, which Vaughan forwarded to Ferdinand Hassler on or about 13 October 1810.1
Letter 2: Nicholas Biddle to John Vaughan
1st. The river Dubois according to the manuscript of Captn. Clarke which forms the text of the narrative 38° 55' 17" the longitude 87° 57∙ 45∙ In my map which is larger and done with more care than that of Mr. Hassler the situation corresponds with those calculations & is I know, almost directly opposite to the mouth of the Missouri. In the same map the 87° degree of longitude crosses the mouth of the Ohio. I incline to think that the slight sketch sent to Mr. Hassler is not to be trusted as to longitude for I understood that its only object was to designate in a general way the places at which the observations were made and of which Mr. Hassler was to fix the longitude by calculation.
2nd. Fort Mandan is mentioned in the manuscript to be in longitude 99. 24. 45–the map has it in 101. There is error somewhere yet it seems difficult to correct it for all that relates to the eclipse in my papers is as follows:"15 Jany. 1805. This morning between 12 and 3 OClock we had a total eclipse of the moon. A part of the observations necessary for our purpose in this eclipse we got—which is
I presume that the time here noted cannot be apparent time or time ascertained by an altitude; nor can it be mean time if by that phrase be meant as I understand time obtained from an altitude corrected by adding or subtracting the equation from the nautical Almanac, since in neither of these cases is it probable that a mistake so great as that of an hour could have occured. But it appears as if the time must be that given by the chronometer at the moment. For in the first place that was the most simple & the probability is that simplest plan was adopted. In the second place from the manner in which the note is made, the silence of the two other persons who kept Journals, and from the circumstance that the young man of the party2 who is now here knowing nothing of it, it seems probable that the eclipse came on them rather unawares and that having made no preparation, they took the only way in their power of recording the precise time. If therefore they took the time by the chronometer which Mr. Hassler thinks might have been fixed for the Ohio or the mouth of the Missouri, the difference of the hour may perhaps assist the calculation of the longitude–for they had travelled 1600 estimated miles on a course somewhere about northwest.
4th. Judging from what I have heard Captn. Clarke mention I had supposed that he expected from Mr. Hassler the astronomical results only, on obtaining which he proposed making the map himself. But on this subject, as well as that last mentioned Mr. H. might perhaps receive every information by writing to him.
5th. I think it is of importance that Mr. Hassler should possess at least all the courses bearings, & distances during the whole route and I should wish him to see the map I have. But unfortunately the map itself as well as the original journals are so indispensably necessary for my own share of the work that I cannot part with them.
1. Jackson, Letters, 2:560-61. Biddle's 3rd point may be the unnumbered fourth paragraph, beginning "I presume...."
2. The young man would have been George Shannon (1785-1836), only 19 when the Corps left Camp Dubois, he was now 25. Clark wrote to Biddle from Louisville on May 22, 1810, to confirm, pursuant to their previous conversation, that the "Young Gentleman" would soon arrive in Philadelphia to answer whatever questions might arise relative to the manuscript journals Biddle was paraphrasing. Clark's recommendation was unqualified: "This Young Gentleman possesses a sincere and undisguised heart, he is highly spoken of by all his acquaintance and much respected at the Lexington University where he has been [studying law] for the last two years." Biddle was thoroughly satisfied. "I have derived much assistance from that gentleman who is very intelligent and sensible & whom it was worth your while to send here." Among other things, Shannon helped him select the subjects for the engravings that were included in the book. Jackson, Letters, 2:549, 568.
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