Paul Revere's Ride

by David Hackett Fischer

  APPENDIX I

  The Moon, April 18-19, 1775

  Many participants remembered that the moon was nearly full on the night of April 18-19, 1775. “The moon shone bright,” Paul Revere wrote in his deposition. His fellow captive Sanderson wrote independently, “It was a bright moon-light after the rising of the moon, and a pleasant evening” (Phinney, Lexington, 31).

  These memories have been confirmed by two American astronomers, Donald W. Olson and Russell L. Doescher, who studied this subject in detail, and found that the nearest full moon occurred on April 15, 1775, and the last quarter on April 22. On the night of the midnight ride, they calculate that “there was indeed a bright waning-gibbous moon, 87 percent sunlit, in Boston on the night of April 18, 1775.” They estimate that the moon rose over Boston at approximately 9:53 p.m., local apparent solar time (approximately 25 minutes later than our modern Eastern Standard Time).

  On that night Olson and Doescher reckon that the moon had a strong southern declination of -18 degrees. If Revere’s friends were rowing him across the Charles River at approximately 45 minutes after moonrise, the moon would have been very low in the southern sky—6 degrees above the horizon, on a true bearing of 121 degrees.

  Revere’s course from the North End of Boston to Charlestown’s ferry landing was approximately 330 degrees. The moon was almost directly behind him, and as it was only 6 degrees above the horizon, his boat would have been shrouded in the dark moonshadow of the town’s skyline, and very difficult to see from the deck of HMS Somerset, or even from British guardboats that were patrolling the river that night.

  The transit of the moon occurred at 2:42 a.m. according to the computations of two other astronomers, Jacques Vialle and Darrel Hoff. The marker in the Minute Man National Historical Park that refers to a third quarter moon is not correct.

  See Donald W. Olson and Russell L. Doescher, “Astronomical Computing: Paul Revere’s Midnight Ride,” Sky and Telescope, April 1992, pp. 437-40; also Jacques Vialle and Darrel Hoff, “The Astronomy of Paul Revere’s Ride,” Astronomy 20 (1992): 13-18.

  APPENDIX J

  Tidal Movements, the British March, and the Midnight Ride, April 18-19, 1775

  Shakespeare observes that “there is a tide in the affairs of men; which, taken at the flood, leads on to fortune” (Julius Caesar, IV, iii, 217). So it was for Paul Revere, but General Gage would have been luckier at the ebb.

  Tidal movements in the Charles River and Boston’s Back Bay had an important impact on these events. Paul Revere remembered that when he crossed the Charles River at approximately 10:30 to 11:00 p.m., “It was then young flood.” The strong Boston tide was flowing into the harbor and running westward up the estuary of the Charles River.

  At that same hour, the British troops were moving across the Charles River to Lechmere Point in Cambridge. Lt. William Sutherland wrote that when they marched along the river at 2 a.m., “the tide being in we were up to our middles.” Mackenzie remembered that the men were “obliged to wade, halfway up to their thighs, through two inlets, the tide being by that time up.”

  Modern computations confirm the accuracy of these accounts. Professors Olson and Doescher, using a method of harmonic analysis, estimate that on the afternoon of April 18, 1775, high tide in Boston harbor occurred at 1:14 p.m. local apparent solar time. Low water followed that evening at 7:19 p.m. and high tide again at 1:26 a.m. in the morning. These results confirm that the tide was rising when Revere and the British soldiers were crossing the river.

  Early American almanacs were even closer to the descriptions of the participants. Three colonial almanacs variously estimated the time of high tide on the morning of April 19 at approximately 2:34 (Low) 2:36 (Isaiah Thomas), and 2:39 (Bickerstaff).

  All this was an advantage for Paul Revere, and a problem for the British expedition. At the point where Revere crossed, the river flowed west around a bend. His course to Charlestown took him upstream. The Regulars crossed further west where the river was flowing southwest. Their course to Cambridge was downstream. Revere’s passage was comparatively short, and as his route took him diagonally upstream he was moving with the tide. The British troops were moving diagonally downstream against the tide over a longer distance. Revere was traveling in a small rowboat with two experienced Boston watermen. The British troops were in heavy, overloaded longboats. The tide gave Revere an important advantage, and was a factor in speeding him on his way, while retarding the progress of the British troops.

  See Donald W. Olson and Russell L. Doescher, “Astronomical Computing: Paul Revere’s Midnight Ride,” Sky and Telescope, April 1992, pp. 437-40.

  APPENDIX K

  The British Concord Expedition: The Problem of Numbers

  No official count of troop strength has been found for this mission. Estimates by participants and eyewitnesses ranged between 600 and 900 men. Barker thought it numbered “about 600 men”; an officer of the 59th Foot, “600 men including officers”; Evelyn, “near 700”; an anonymous light infantryman, precisely 756; and Richard Pope, “nearly 800 men.” One observer, Boston printer John Boyle, counted “about 900 Regular troops, but his estimate has been rejected by all historians of the battle as too high. Cf. John Boyle, “Boyles Journal of Occurrences in Boston, 1759-1778,” NEHGR 85 (1931) 8.

  The estimates of historians have tended to vary according to their politics. In general, the more Whiggish the scholar, the larger his estimate of British numbers; the more Tory or Anglophile, the smaller the force becomes. The Whig historian Gordon reckoned the force at “800 men or better.” Bancroft, Coburn, Frothingham, Hale, Hudson, Lossing, and Shattuck were content with 800. Robert Gross preferred “seven to eight hundred.” French, Tourtellot, and Galvin reckoned “in the neighborhood of 700.” The American Anglophile Harold Murdock extrapolated from average company strength of the 23rd Foot (28.2 men) to a controlled guess of 588 rank and file.

  These estimates derive mainly from impressions of contemporaries, and the conventional judgments of other scholars, and in the case of Murdock from a strength report for a single regiment, drawn from the diary of Frederick Mackenzie.

  Monthly strength reports for all units engaged at Lexington and Concord are missing in the Public Record Office, but another source helps to settle the question. Regimental rosters and paylists are available for the 1774-75. Each regiment submitted twice a year a roster, sworn before a magistrate and witnesses. These documents were meticulously compiled in elaborate detail. A separate folio sheet was prepared for each company, listing by name and rank every man who had served in the unit since the last report, with dates of duty, promotions, transfers, leaves, desertions, discharges, detached duty, etc. The Boston regiments in general submitted reports in the winter of 1774—75, and again in the summer of 1775. These documents were not snapshots, but moving pictures. They are imperfect in some details. Men who were relieved from duty for sickness or wounds or special assignments were listed only for the end of the reporting period, but not for other dates. Other movements are noted throughout the reporting period. These records reported an extraordinarily high rate of turnover. Men were frequently transferred in and out of individual companies, commonly from other units in the same regiment. Recruits and replacements arrived throughout the period.

  No rosters were found for the British Marines before 1777. By the beginning of that year, the “American battalion” that had served at Boston had moved to Halifax. Its grenadier company had a strength of 3 officers and 29 men. Its light infantry company (the same that marched to Concord) was very much larger, with 117 other ranks; but it is not clear that the company was of similar size in April, 1775. Another method of estimation was used here to avoid an overcount. The total strength of the British Marine battalion in Boston was reported by its commander Major Percy at 387 effectives, 22 percent larger than the mean effective strength of the army regiments in Boston on April 1, 1775. An estimate for the Marine grenadiers and light infantry companies was added here in the same ratio, as 122%
of mean strength in other companies. If the earliest pay rosters are an accurate indicator, the true strength was not 43 but 73 rank and file. The smaller number is used here, as a lower-bound estimate. Contingency men are not included.

  These lists indicate the following numbers of “effectives” as of April 18, in the companies that marched to Lexington and Concord:

  There may have been as many as seven additional members of Mitchell’s party, and perhaps another 60 Marines, if the 1777 rosters are correct, and Loyalist volunteers, minus one straggler at the Phips farm. The size of the Concord expedition might therefore have been as large as 909 officers and men. If so, the rejected estimate of John Boyle proves to be the most nearly accurate.

  Are the muster rolls a trustworthy source? For the 23rd Royal Welch Fusiliers they can be tested against the diary of Frederick Mackenzie, who reported that the number of rank and file under arms on April 19 was precisely the same to the man as the estimate that emerges from the rosters. Gage and Haldimond established elaborate procedures to ensure accurate and honest reports, and were successful.

  There is only one possible source of error. These estimates assume that the proportion of men who were ill, absent, on detached duty or otherwise “ineffective” was the same on April 19 as at the date of the preceding roster (circa Jan. 30, 1775). There was some attrition in Gage’s army during the entire period. From January to June, net attrition other than losses in combat totalled only 1.9% for the rank and file in all companies of every marching regiment. A special effort was made to keep up the strength of grenadier and light infantry companies by transfering men from the line companies (Barker, British in Boston, 58-59). Even the mean attrition rate of the garrison as a whole would reduce these estimates by only 15 men. For flank companies, the wastage was smaller, and the net change may actually have been in the opposite direction, as men on detached duty returned to their units when they went on active service.

  The sources for these estimates are Regimental Rosters in WO12, PRO. Cf. Barker, British in Boston, 31; W. G. Evelyn to his father, April 23, 1775, Scull, Evelyn, 53; an anonymous light infantryman in Letters on the American Revolution, 187—200; Pope, Late News, entry for April 18, 1775; French, Day of Concord and Lexington, 73; Murdock, The Nineteenth of April, 47; Tourtellot, Lexington and Concord, 104; Gross, Minutemen and Their World, 115.

  APPENDIX L

  A Chronology of the British March, April 18-19, 1775

  Many contemporary estimates are available for the chronology of the British expedition. With allowances for a range of variation in individual timepieces, they roughly agree. But several historians have rejected them. The first to do so was Frank W. Coburn, who in general revised the estimates of participants, assigning earlier times for the British march to Concord, and later times for the return. Allen French followed Coburn, but sometimes blurred individual events where discrepancies were specially apparent. Arthur Tourtellot was erratic, but tended to split the difference between Coburn’s estimates and those in primary sources. These historians, who shared the general opinion that Smith was “very slow,” could not believe that the British march was as rapid as contemporary estimates indicated.

  This inquiry finds that the estimates of eyewitnesses were generally consistent, and the speed of the march was compatible with their descriptions of it. Further, a comparison of solar times with their estimates of the relationship of sunrise and sunset to events of the march confirms the accuracy of participant-observations. Coburn, French, and Tourtellot all followed one another into error on this question.

  In the following variant estimates, primary sources are given in roman type; secondary estimates in italics.

  APPENDIX M

  The British March: Time, Distance, Velocity

  APPENDIX N

  Methods of Timekeeping in 1775

  Where clock time was given, it differed from the temporal conventions we keep today. Since 1883, Boston has run on Eastern Standard Time, which was invented to synchronize railroad timetables. In 1775, watches and clocks were commonly set by sunlines at high noon, or by what is called today local apparent solar time.

  All estimates in this work should be understood as an approximation of local apparent solar time, not Eastern Standard Time. To convert from local apparent solar time to Eastern Standard Time in the longitude of Boston, one must subtract 25 minutes. If Paul Revere left Charlestown at 11:00 p.m. local apparent solar time, the equivalent would be 10:35 p.m. Eastern Standard Time, or 11:35 p.m. Eastern Daylight Time.

  American clock-time in many accounts referred merely to the nearest hour. Some American clocks in 1775 had no minute hand. American narratives marked the time not by hours but natural events—sunrise and sunset, or the rising of the moon. One event was recorded as happening between first light and sunrise.

  British officers tended to observe clock time and often used fractions of hours and even minutes. Elijah Sanderson, the Lexington man who was captured by the British patrol later testified, “They detained us in that vicinity till a quarter past two o’clock at night. An officer, who took out his watch, informed me what the time was” (Phinney, Lexington, 31).

  Neither side appears to have synchronized watches, a practice that appears to have begun among Union armies in the west during the Civil War. In other wars during the 20th century, opposing sides set their clocks differently. This was not the case at Lexington and Concord. In some instances, British estimates of times tended to be later than those of the Americans. But the difference was small and inconstant.

  One test of the accuracy of temporal estimates can be made by comparing hours of sunrise and sunset with primary estimates of the chronology of events. Many eyewitnesses on both sides wrote that the Regulars arrived at Lexington Green just at sunrise. They also agreed that the battle ended when Percy’s brigade crossed Charlestown Neck at sunset. These events may be used to assess time-keeping by participants and historians. In general they confirm the accuracy of estimates by participants, and contradict the revisions that were introduced in the literature by Coburn, French, and in some cases by Tourtellot. On April 19, 1993, the hours of sunrise and sunset were as follows:

  This suggests that estimates of time by British officers were in general roughly accurate when understood as local apparent solar time. Secondary accounts by Coburn and French deliberately altered these times for the march from Cambridge to Concord, to conform with their understanding of events. They all believed that Col. Smith was “slow,” and could not square that assumption with primary estimates of the rapidity of the British march. Rather than rethinking their assumption, they revised the evidence. A comparison of solar times with contemporary estimates shows that these revisions were erroneous. The student of the battle should in general trust the preponderance of primary temporal estimates, and reject those in secondary accounts by Coburn and French. These secondary works remain very valuable in other respects, but not on questions of chronology.

  SOURCE: Nathaniel Low, An Astronomical Diary; Or, Almanack for the Year of Christian Era, 1775 (Boston, 1775); solar tables, 1993.

  APPENDIX O

  The Lexington Militia: Quantitative Research by Jeremy Stern for this volume

  Strength: The muster rolls of the Lexington Company, and lists compiled by Charles Hudson for his history of Lexington identify 141 men of all ranks. Of this number as many as 75 have been identified as present on Lexington Green when the first shot was fired. The total number of male polls in 1771 was 185; in 1775, 208; in 1785, 196; in 1790, 205. The number of males aged 16 and older in the census of 1790 was 251. The total population of the town was enumerated at 755 in 1770 and 941 in 1790.

  Age: The youngest militiaman was 16; the oldest, 66. Of those whose ages are known, 16.4% were under the age of 20; 25.5% were 20-29; 36.5% were 30-39; 13.6% were 40-49; and 8.2% were 50 and older. A total of 58.3% were 30 and older. Mean and median ages were in the range of 31.8 to 32.8. The Lexington militia were older than the Concord minutemen, as estimated
by Robert Gross. In general, minutemen in many towns appear to have been younger than the militia, and much younger than men on the alarm lists, and not representative of the men who mustered and fought that day.

  Prior Military Service: From incomplete records, Charles Hudson estimated that a minimum of 28 to 33 men in Lexington, ca. 1775, who had seen active service in the French and Indian War. Probably the true number was much higher. The age of veterans in Captain Parker’s company ranged from 62-year-old Ensign Robert Munroe to Amos Locke, aged 32.

  Wealth: A linkage of various 1775 muster lists with the 1771 tax list shows that nearly all of these men were small landowners, neither rich nor poor. Of 141 men, 78 could not be located on the tax list of 1771, in almost all cases because they were under 21, or had not moved into the town, or could not be conclusively identified. Of 63 militiamen who could be identified, 58 were landowners in the town. Only 5 owned no land. The largest holding was assessed at 19 pounds annual worth, a comfortable but modest estate. Captain Parker was assessed at 11 pounds. Of the ten richest men on the list, eight were privates.

  Kinship: The muster lists of the Lexington company included 16 Munroes, 13 Harringtons, 11 Smiths, 8 Reeds, 4 Browns, 4 Hadleys, 4 Muzzys, 4 Hastings, 4 Tidds, 3 Simonds, 3 Wellingtons, 3 Winships, and many pairs. Only 27 men of 141 did not share a name with another member of the company. The great majority belonged to one extended cousinage.

  APPENDIX P