NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Places where Slocum mentions navigation-related items
From: Frank Reed CT
Date: 2003 Dec 23, 16:47 EST
From: Frank Reed CT
Date: 2003 Dec 23, 16:47 EST
Jan Kalivoda, you wrote:
"Frank, from one your answer to Fred, one can assume:
- the scarcity of Slocum's remarks about noon observations is the proof that such observations were so common for him that he didn't pay attention to them in his narration
- the scarcity of Slocum's remarks about lunars is the proof that he didn't use lunars in other times than he mentioned it explicitly
Am I right in following your argumentation?"
In an over-simplified way, of course, that's right. But what of it? Fred's count of noon sun sights is what is commonly refered to as a "straw man" argument. It's a distraction. There is not the slightest doubt that Slocum got his latitude by Noon Sun sights each and every day that the Sun was visible. Shooting the Sun for latitude was a commonplace for a couple of centuries before the voyage of the Spray and for decades after it, and everyone knew that at the time and knows it today. Counting up Noon Sun sights is pointless. For another analogy, how often does Slocum mention ordinary waves? Not all that often. How often does he mention a rogue wave? Once. Can you reach any conclusion about the number of rogue waves he saw based on the number of ordinary waves he describes in the book? Could you multiply the number of ordinary wave references up by some factor and then conclude that he probably saw dozens of rogue waves? Of course not. He saw one, and he mentioned it because it was extraordinary. The scarcity of references to ordinary waves doesn't help us estimate the number of rogue waves.
Similarly, navigating by lunars was an extremely rare activity in the late 1890s --one that would merit mention precisely because it such a unique activity (and Slocum waxes poetic about it on that one day precisely because it was a nearly forgotten practice at that point in time). Did Slocum shoot lunars on one afternoon in the western Pacific?? Yes indeed. He says so. Did he shoot any others?? Maybe he did. Maybe he didn't. Slocum states very clearly in his own words that he found his "longitude, at least, mostly by intuition". He did not shoot lunars on anything like a regular basis. If there is evidence for a more regular and systematic use of lunars on the voyage, where is it? Slocum describes dead reckoning techniques in several places, but there is no further mention of lunars in SAATW beyond that one afternoon in the western Pacific. There may be other sources though: newspaper accounts of his voyage, descriptions of his logbook if not the logbook itself, contemporary accounts of the voyage in the navigation literature. I would love to hear of them --really.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
"Frank, from one your answer to Fred, one can assume:
- the scarcity of Slocum's remarks about noon observations is the proof that such observations were so common for him that he didn't pay attention to them in his narration
- the scarcity of Slocum's remarks about lunars is the proof that he didn't use lunars in other times than he mentioned it explicitly
Am I right in following your argumentation?"
In an over-simplified way, of course, that's right. But what of it? Fred's count of noon sun sights is what is commonly refered to as a "straw man" argument. It's a distraction. There is not the slightest doubt that Slocum got his latitude by Noon Sun sights each and every day that the Sun was visible. Shooting the Sun for latitude was a commonplace for a couple of centuries before the voyage of the Spray and for decades after it, and everyone knew that at the time and knows it today. Counting up Noon Sun sights is pointless. For another analogy, how often does Slocum mention ordinary waves? Not all that often. How often does he mention a rogue wave? Once. Can you reach any conclusion about the number of rogue waves he saw based on the number of ordinary waves he describes in the book? Could you multiply the number of ordinary wave references up by some factor and then conclude that he probably saw dozens of rogue waves? Of course not. He saw one, and he mentioned it because it was extraordinary. The scarcity of references to ordinary waves doesn't help us estimate the number of rogue waves.
Similarly, navigating by lunars was an extremely rare activity in the late 1890s --one that would merit mention precisely because it such a unique activity (and Slocum waxes poetic about it on that one day precisely because it was a nearly forgotten practice at that point in time). Did Slocum shoot lunars on one afternoon in the western Pacific?? Yes indeed. He says so. Did he shoot any others?? Maybe he did. Maybe he didn't. Slocum states very clearly in his own words that he found his "longitude, at least, mostly by intuition". He did not shoot lunars on anything like a regular basis. If there is evidence for a more regular and systematic use of lunars on the voyage, where is it? Slocum describes dead reckoning techniques in several places, but there is no further mention of lunars in SAATW beyond that one afternoon in the western Pacific. There may be other sources though: newspaper accounts of his voyage, descriptions of his logbook if not the logbook itself, contemporary accounts of the voyage in the navigation literature. I would love to hear of them --really.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
