I’m a scientist by training. I received my master’s degree from MIT, which is incidentally where I fell in love with Boston’s revolutionary history.
So, when I first began researching my forthcoming book on Revolutionary Boston, I approached the research very scientifically, considering things like moonlight phases, sunsets, horse gaits and their associated speeds, and speeds of a typical march of a column of men (of which I have some familiarity, being in the US Military).
One of the manifestations of this approach is my trying to map the chronology, as nearly accurate as possible, to key events, such as the Battle of the Nineteenth of April and the Battle of Bunker Hill. At times, it became literally mind-boggling to do this, when evidence conflicted. But at the end of the day, historians must make smart assessments to fill in the unknown, and that’s often where the scientific approach helped fill in missing data.
With the coming of the anniversary of April 19 (the day of the first shots of the American Revolution), I thought I’d share two of the more interesting findings of that timeline analysis.
Dawes and Revere’s Respective Rides
In my previous article on Dr. Joseph Warren’s informant, I touched on the fact that William Dawes must have ridden out of Boston Neck before it was shut for the night on April 18, which is obvious. Since the curfew for Charlestown Ferry was at 9 PM every night, it seems logical to believe the same curfew applied to Boston Neck gate. Dr. Warren had several indications of a British movement that night, but the most important one came at 8 PM, when, per Admiral Graves’s orders, “The [Navy] Boats [were to]… assemble along side the Boyne by 8 o’Clock in the Evening”. This is what seems to have prompted Warren to call on Dawes as an informational courier. So we have Dawes leaving sometime between 8 and 9 o’clock, say 8:30 PM.
Dr. Warren did not have the definite evidence of a British march, and was loath to send another alarm since he had already sent Revere out on two false alarms in the previous days. Hence, Dawes rode off with no particular urgency, taking the circuitous road from Boston Neck gate and through Roxbury, west through Brighton, up the Great Bridge across the Charles River (where the Anderson Memorial Bridge is now), through Cambridge center, then up what is essentially Massachusetts Avenue, all the way to the Rev. Jonas Clarke home in Lexington, where Samuel Adams and John Hancock were hiding out. Comparing old maps and overlaying them to modern mapping tools, this total distance was about 16.5 miles, and there is no evidence that Dawes alerted anyone along the way. After all, he had left when nothing was confirmed.
Meanwhile, British troops began to muster on Boston Common at 10 PM, which was the impetus for Warren finally calling Revere to his house and giving him instructions to again send the alarm to Adams and Hancock in Lexington. Revere himself wrote, “About 10 o’Clock, Dr. Warren Sent in great haste for me…”, meaning Warren’s unnamed aide showed up at Revere’s house sometime after 10 PM, and then the two rushed over to meet Warren at his nearby house, where Warren then divulged the news of the impending British march (not learned from some secret informant, but witnessed by Warren himself, as demonstrated in my last article). By now, after Revere’s instructions were issued, it was perhaps 10:20 PM.
Revere then states after his crossing the Charles River and getting a horse in Charlestown, “it was then about 11 o’Clock”. It was probably more like 11:15 PM, which allows Revere a near full hour from departing Warren’s house, alerting those that were to light the two lanterns at Old North Church, and then getting his riding spurs and finally crossing the Charles, where he then paused to discuss with the Charlestown militia for a time before getting his horse ready.
Now we must account for Revere’s avoiding a roving British patrol, backtracking, and taking the northern route of what is now Mystic Avenue to High Street (in Medford). From there, he rode west to where it becomes Medford Street and then joins Massachusetts Avenue (in modern Arlington), which he then took up to Lexington. Revere’s total distance was about 12.5 miles. His was a mission of urgency, so a fast canter seems appropriate for his horse’s average speed (it is not plausible that he kept the horse at a full gallop that far), so let us assume an average of 15 mph. (But even this is assuming a fast travel time for Revere—his horse was likely slower.) For that speed and distance, this works out to 50 minutes. Revere adds, “In Medford, I awaked the Captain of the Minute men; & after that, I alarmed almost every House, till I got to Lexington.” For this, we must add some minutes more. So, this puts Revere at Rev. Clarke’s house in Lexington closer to 12:30 AM, April 19.
Revere wrote that he arrived at Rev. Clarke’s “bout half an Hour” before Dawes. So we have Dawes’s arrival at about 1:00 AM, April 19. Working backward to check our math, if Dawes left at 8:30 PM, and thus took 3.5 hours to travel 16.5 miles, assuming no stops (again, no evidence he warned anyone along the way) and no delays from British patrols, he travelled at about 5 mph, or slightly faster than the average walk speed of a horse. This is consistent with Dawes’s errand: he left before there were definite signs of a British march, and his message was only that the British were astir in Boston. Dawes had no reason to race his horse across the countryside. Moreover, his horse has been described as a pack horse in secondary sources, which implies it was not suitable for fast courier missions anyhow. As a result, with Revere racing to Lexington with urgent business, he beat Dawes there.
I had always wondered why Dawes was so late, and why Revere got all of the credit. But in analysis as described above, the answer becomes clear. (Of course, Longfellow’s immortal poem also ensures Revere’s place in history.)
I used this kind of analytical analysis in much of my research, especially for the Battle of April Nineteenth and of Bunker Hill. As a result, there are many little nuggets that reveal themselves besides the one above. I will share just one more here.
Samuel Adams to John Hancock:
“This day is a glorious day for America!”
Without going through the minutia, if I continue the same type of analysis as above, I find that Revere and Dawes departed Lexington to alert the western countryside near 1:30 AM. Soon after riding off, they encounter Dr. Samuel Prescott. With careful mapping, we find the now trio of alarm riders only made it 3 miles before they encountered a British patrol, probably at about 1:50 AM. Those mounted patrolmen sent Dawes and Prescott scurrying and captured Revere. That’s right: Revere’s more famous part of his famous ride might’ve lasted only about 20 minutes! If not, it certainly wasn’t much longer than that.
By correlating what the Lexington Militia Company was doing on nearby Lexington Green, and their volley before going into Buckman Tavern, which startled Revere’s captors who were escorting him back that way and so convinced them to release Revere and speed along, we have Revere’s release at about 2:30 AM. Horseless, Revere made his way the short remaining distance back to Rev. Clarke’s house, and soon after escorted on horseback both Adams and Hancock (in horse and carriage) a short ways northeast along their escape towards Woburn, departing at about 3:30 AM. (Once on their way, Revere was sent back to Lexington to fetch some revolutionary papers in a chest upstairs in Buckman Tavern.)
About this time, some modern versions of a tradition give that Samuel Adams turned to Hancock and said, “It is a fine day!”
“Very pleasant,” Hancock replied, noting the mild weather.
“I mean,” Samuel was forced to clarify, “this day is a glorious day for America!”
One of the original sources for this tradition states this was said at dawn, and so modern historians have then deduced the above dialogue was in response to having heard the first shots at Lexington. However, at even a mere 4 mph (the speed of a horse’s walk), with a departure of 3:30 AM, Adams and Hancock would have arrived in Woburn, just over 4 miles away, by not much later than 4:30 AM. By multiple accounts, the British arrived at Lexington Green at sunrise, which was 4:57 AM.
Thus, by dawn, Adams and Hancock were far enough away that, between the distance and the many intervening trees muffling the sound, it is unlikely the two actually heard the start of the Revolutionary War. If those traditional lines were indeed spoken, it was merely in reference to the expected British arrival, not in reference to hearing those first shots.
Those are just two examples where a scientific approach helps to fill in some of the many gaps in our understanding of the details of the Revolutionary War, and in doing so, adds depth and richness to the body of our understanding.[Featured Image at Top: Map depicting the outbound routes taken by Dawes, Revere and British troops on April 18-19, 1775. Source: National Park Service]
All dates are 1775 unless otherwise noted.
 US Navy’s Sun & Moon Calculator at http://aa.usno.navy.mil/data/docs/RS_OneDay.php.
 Susan E. Harris’s Horse Gaits, Balance and Movement (New York: Howell Book House, 1993) gives the following average speeds for the four horse gaits: walk: 4 mph (p. 32-35); trot: 6-8 mph (p. 35-42); canter: 9-17 mph (not explicitly given, but inferred between a trot and gallop; p. 42-47); gallop: 18-30 mph (45 mph for a race horse, which none of these revolutionary steeds were; p. 47-49).
 It is commonly called the Battle of Lexington and Concord. I believe that title ignores all of the other fighting that day, particularly at the most bloody of all of the skirmishes: in Menotomy (modern Arlington). In truth, the day-long battle encompassed many locations, with Lexington being but a skirmish (and in fact there were two skirmishes at Lexington Green that day), and that at old North Bridge in Concord being the same. Thus, the Skirmishes of Lexington and Concord are but two of the many skirmishes in what I called the Battle of April Nineteenth. This title better captures the events of the day, and does not diminish the value of the bloodiest Skirmish of Menotomy.
 William W. Wheildon, Curiosities of History: Boston… 1630-1880 (Boston: Lee and Shepard, 1880, 2nd ed.) 36 http://books.google.com/books?id=w4MUAAAAYAAJ.
 Graves’s Conduct, Apr 18, a transcription at Mass. Hist. Soc., this portion republished in Naval Docs. of the Amer. Rev. 1:192.
 Frederick Mackenzie’s Diary (Apr 18), in A British Fusilier in Revolutionary Boston, ed. Allen French (Cambridge, MA: Harvard Univ. Press, 1926) 50-51 http://www.archive.org/details/britishfusilieri009630mbp.
 Paul Revere to Jeremy Belknap, [circa 1798]. The earlier two depositions by Revere, from 1775, also agree. The three depositions are as follows: “Deposition Draft”, circa May 1775; “Deposition Draft [Corrected Copy]”, circa May 1775; “Paul Revere to Jeremy Belknap [circa 1798]”. The originals of all are at MHS, but reprinted in many places, the latter is in Proc. of MHS (1878) 16:371-76 and at http://www.masshist.org/database/onview.cfm?queryID=112.
 This earliest version of the quotation is from John Eliot’s A Biographical Dictionary (Salem, MA: Cushing and Appleton; Boston: Edward Oliver; 1809) 10 http://books.google.com/books?id=2C4EAAAAYAAJ, which states the exchange happened “after the day dawned”. Eliot would have known Samuel Adams personally, and may have confirmed the story. A slightly different version in William Gordon’s The History of the Rise, Progress and Establishment of the Independence of the United States… 3v. (New York: Printed for Samuel Campbell by John Woods, 1801, 3rd. ed.) 1:311 (v.1 at http://google.com/books?id=gyQwAAAAYAAJ). Modern histories like David Hackett Fischer’s Paul Revere’s Ride (New York: Oxford University Press, 1994) 183, in considering the first shots were at dawn and the dialogue was also at dawn, put the two together and report the dialogue was Samuel Adams responding to having heard the first shots as they escaped Lexington. And yet, all three of Paul Revere’s statements, including his two depositions given immediately afterward, give a timeline that confirms Adams and Hancock were well on their way to Woburn about 1.5 hours before dawn, since Revere himself went with these men at least part of the way (the earlier depositions say 2 miles, the 1798 letter suggests all the way), then had time to go all the way back to collect the papers at Buckman Tavern, just as the British were arriving (at dawn). Hence, if this traditional commentary from Adams indeed occurred upon departing Lexington or on the way to Woburn, it was before the first shots were fired at dawn. Alternatively, if the commentary was said at Woburn (likely, since they were there by dawn and this matches the Eliot timeline), then Adams and Hancock were well beyond where they could have heard those first shots. In either case, the traditional commentary was not said in response to having heard the first shots.
 On the British arrival at Lexington Green, we have Robbins’s Deposition in Force 4:2:491, which claims “sometime before sunrise” the militia was formed, and the British arrived just moments later. Draper’s Deposition, in ibid. 495, gives “about half an hour before sunrise”, but seems far too early… maybe that’s when they heard them coming or first saw them over the horizon. Lt. Barker in British in Boston 32 gives “about 5 o’clock”. We can safely guess it was approximately sunrise, essentially 5:00 AM, but certainly well within civil twilight, bright enough for all the combatants to see one another. If we ascribe to the sunrise arrival, it was about 4:57 AM, per Navy’s Sun and Moon Calculator, cited above.
When I was in graduate school, dodging pterosaurs and T-Rexes, the new intellectual fad was interdisciplinary research. In some cases, it was important to know the weather, the movement of tides, the language patterns across presumed migration routes and other strange sources of information other than from strictly historical sources. It’s great to see Derek’s work draw upon the precision of time, geography, animal behavior and military science. It’s the kind of study that very much works for me. Looking forward to his book.