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Frank,
Do you have any notes/ recording of the course that you teach?
Perhaps from the previous years.

Alex.
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From: NavList@fer3.com [NavList@fer3.com] on behalf of Frank Reed [NoReply_FrankReed@fer3.com]
Sent: Monday, August 6, 2018 11:45 AM
To: eremenko@math.purdue.edu
Subject: [NavList] Re: 1870s navigation

Bravo. You have recognized an important concept early on that so many students 
of navigation history stumble over for years: navigation manuals display the 
history of education resources, not navigation. They can provide insight and 
bakground, but they are not history. You need to look at "primary sources" 
when researching history. Of course, there are also other secondary sources 
worth digging into, and one that you must read (and should probably try to 
acquire in hard copy) is Lecky's "Wrinkles in Practical Navigation" 
originally published in 1883. It's both practical guide and memoir.

If you can make your way to Mystic Seaport Museum in Mystic, Connecticut in 
October, I highly recommend you join my class "Celestial Navigation in the 
Age of Sail" (formerly "Celestial Navigation: 19th Century Methods" which is 
entirely devoted to this topic and will give you direct practical experience 
with the methods that were used by drawing on late 19th century primary 
sources.

You wrote:
"By analogy, a completely naive person looking at modern US drivers' license 
manuals might infer that only criminals drive over the speed limit, and would 
have no way of knowing that on any real world US interstate highway, driving 
a few mph over the limit is the norm, not the exception."

That's a really good analogy. It's always instructive to imagine how future 
historians two centuries from now might try to understand the world we live 
in today. What distorted lens would the world of youtube provide?! By the 
way, those "few mph over the limit" vary across the country. I spent most of 
my adult life driving in the Midwest (near and in Chicago) and in New 
England. On the interstates in this part of the country, that margin above 
the speed limit is comfortably 7-10 mph. Driving on I-95 out here, I normally 
engage the cruise control at 72mph while the posted limit is 65, and I am 
right in the middle of the pack. That cruising speed is only slightly above 
the mean driving speed on the highway, and it's highly unlikely that a driver 
would be ticketed, or even noticed, in New England for driving at that speed. 
But some years ago when I drove out to California (primarily for a little 
NavList gathering for in-flight aerial sextant sights organized by Gary 
LaPook!), as I drove across Texas and then into New Mexico and Arizona, I 
noticed something interesting: speed limits jumped up, but that margin of 
casual speeding nearly disappeared -- everyone drove at the speed limit. I 
was stopped by a state cop in Arizona on the way back (clearly thinking I was 
a smuggler...), and while he was asking me leading questions about my trip, 
we chatted about that speeding margin. He had a name for it, which I don't 
recall, and he specifically told me that he often stopped and warned drivers 
from other parts of the country who didn't realize that Arizona did things 
differently. There's a different legal standard in that part of the country. 
The speeding margin is 2-3 mph above the posted limited, and the average is 
right on the posted limit. Now there's something you would be hard-pressed to 
learn from a driving manual.

Frank Reed
Clockwork Mapping / ReedNavigation.com
Conanicut Island USA

   

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