Summer 2007

Mike Frost has spent many hours, indeed days researching the old records and archives in Coventry, Oxford and St Johns College, Cambridge to track down any information on other Coventry born astronomers; and they have graciously given their permission for him to use their material for this issue of MIRA, which we can now enjoy.  Ed

Samuel Foster and his Observations from "Distant Places"

By Mike Frost

I'm sure you'll remember that, in the run up to the Transit of Venus on June 8th 2004, I spent quite a lot of time researching, writing and lecturing on Jeremiah Horrocks, the first man to predict and then observe a Transit.  Horrocks's is an inspirational tale of a young scientist, working alone in the Lancashire village of Much Hoole, who managed to predict an event nobody else even realised was going to happen; who observed when not obliged by "greater things, which it was certainly not proper to neglect for these subordinate pursuits", and who finally, on November 24th 1639 [Old Style], when the clouds parted barely 30 minutes before sunset, was greeted by "the most agreeable spectacle" of Venus on the solar disk.
Quite a number of popular accounts of Horrocks's observations (many of them by me) appeared around the time of the 2004 Transit.  Most of these accounts mention that Horrocks only had time to warn two of his fellow astronomers.  Horrocks himself tells us that his friend and correspondent William Crabtree, who had observed diligently all Sunday, was finally rewarded with a glimpse of the Transit just a few minutes before the Sun set. Horrocks also tells us that his brother Jonas observed from Toxteth, but saw nothing (perhaps because of cloud).
Only a few of the popular accounts mention that Horrocks attempted to contact a third observer - Samuel Foster, the subject of this article.  In the letter in which he alerted William Crabtree to the possibility of a Transit, Horrocks also writes 'If this letter should arrive sufficiently early, I beg you will apprise Mr. Foster of the conjunction [Transit of Venus], as, in doing so, I am sure you would afford him the greatest pleasure.'
Horrocks and Crabtree had (probably) known Samuel Foster from three years earlier, when he had held the post of Professor of Astronomy at Gresham College in London. Unlike some of the more theoretically minded thinkers of the day, people whom Horrocks derided, Samuel Foster was an active astronomer, who gathered around him a group of fellow observers.  As we'll see, accounts of their observations still exist.  A near-contemporary record tells us that Foster made observations "at Gresham College... [and] in other distant places". Foster might not have considered his observations to have been from "distant places", for he had returned to the city which may well have been his birthplace, was certainly the home of some of his family, where he had taught at the local school, and where he wrote the two works that were published in his lifetime.
In the late 1630's, Samuel Foster was living in Coventry.

Birthplace and Family History
As with Jeremiah Horrocks, the family history of Samuel Foster is threadbare and sources contradictory.  The closest we have to a contemporary biography is from Aubrey's "Brief Lives", published in 1680.  John Aubrey was born in Wiltshire, studied Stonehenge (giving his name to the feature called "The Aubrey Holes") and then moved to Oxford, where he became an antiquarian and compiled a wonderfully idiosyncratic, eclectic and entertaining series of potted biographies.  Aubrey's life of Samuel Foster is one of the briefest:
"From Mr Beyes, the watchmaker, his nephew: Mr Samuel Foster was born at Coventry (as I take it); he was sometime usher of the school there.  Was professor at Gresham College, London: where in his lodging, on the wall, in his chamber, is, of his own hand drawing, the best sundial I do verily believe in the whole world.  Among other things it shows you what o'clock 'tis at Jerusalem, Gran-Cairo etc.  It is drawn very skilfully."
The biography indicates the field in which Samuel Foster was most famous - the design and mathematical development of sundials.  Aubrey's biography would seem to be definitive on Foster's birthplace, were it not for the "as I take it", a typically woolly addition. Unfortunately the next biography to appear contradicts Aubrey.  John Ward's "Lives of the Professors of Gresham College", published in 1740, has a longer account, which begins:
"Samuel Foster was born in Northamptonshire, and admitted a sizar at Emmanuel college in Cambridge on 23 of April 1616, where he took the degree of batchelor of arts in the year 1619, and that of master in 1623. The following year he published his treatise, called 'The Use of the Quadrant'".

Samuel Foster's signature

I have made several attempts to find out which of the two suggested birthplaces is the correct one.  First, I wrote to both the Northamptonshire and the Warwickshire Record Offices.  Northamptonshire told me they had no information on Samuel Foster.  However, G.M.D. Booth, the Senior Archivist of Warwickshire County Record Office, was rather more forthcoming, if still inconclusive:
" ... We have had enquiries about Samuel Foster before, and the suggestion was made that he was born not far from Newhall Green (where he apparently lived in the 1630s). We searched the registers of the parishes of Fillongley, Great Packington and Corley (as Newhall lies in Fillongley but near to the other parishes) but without any success."
We'll see later where the Newhall Green suggestion might have come from.
Another line of attack was to search for Samuel Foster and his known family in the online genealogy sites.  I know of three siblings; an elder brother, Walter, of whom more below; and two sisters, Martha and Elizabeth, who are mentioned in Foster's will.  Martha's married name was Beyes and so it's reasonable to conclude that she was the mother of the watchmaker mentioned by Aubrey.  Martha lived in Coventry, and Elizabeth, who took the married name Poyner, lived in Northampton.  There is also a cousin, Thomas Martin, who was minister of Little Houghton, a village south of Northampton.
A search on www.familysearch.org turned up several of these names in the right locations at around the right period.

* In 1575, Elizabeth, daughter of Richard Foster, was baptised at Holy Trinity, Coventry [probably too early]

* On December 21st 1599, a Martha Foster was baptised at Braunston [mid-way between Coventry & Northampton]

* A Foster family lived in Moulton, a village north of Northampton. Libeas Foster, son of John Foster, had 8 children: William (born 1 / 1 / 1598), Walter (1600), Sarah (15 / 8 / 1602, Jane (8 / 7 / 1604), Thomas (Jan 1607), John (1 / 11 / 1609), Ann and Elizabeth (24 / 4 / 1612). [Walter and Elizabeth but no Martha and NO SAMUEL - so almost certainly a red herring!]

Frustratingly, although there are candidates in both Coventry and Northampton, and half-way between, I don't believe any of these is genuinely Samuel Foster's family.

Education at Cambridge
John Ward's biography indicates the next phase of Samuel Foster's life; his education at Emmanuel College, Cambridge.  Foster is part of a great tradition of Emmanuel astronomers - others include Jeremiah Horrocks (admitted 1632), Fred Hoyle (admitted 1933) and me (admitted 1981).  Foster and Horrocks belong to the extraordinary cohort of students who studied at Emmanuel in the first half century of its existence, 1584 - 1634.  In addition to Foster and Horrocks, other Emmanuel scientists from this era included two more astronomers, John Bainbridge and John Palmer; and John Wallis, geometer and cryptographer, who anticipated Newton's ideas on infinite series.  All three feature later in this article.

Emmanuel College register for 1616, showing Samuel Foster's signature on April 23rd

Emmanuel College register for 1632, showing Jeremiah Horrock's signature on May 18th

During the first half of the seventeenth century, Emmanuel College was the country's leading centre for non-conformist thought.  This attracted philosophers of the puritan neo-Platonic tradition, such as Ralph Cudworth and John Worthington, not to mention an extraordinary number of people who went on to emigrate to the American colonies, including William Blackstone (first settler in Rhode Island), John Cotton (eminent preacher) and John Harvard (founder of America's first university).  It is said that 35 of the first 129 Oxbridge graduates in the American colonies (up to 1650) were educated at Emmanuel.
I re-visited the college archives at Emmanuel to look at the college entry register.  When Jeremiah Horrocks signed this register on May 18th 1632, he indicated "Lancastro" (county of Lancashire) as his county of origin.  John Harvard's registration in 1629 is less clear, but I think that I can make out "Stratford, Warwickshire".  Unfortunately, Samuel Foster's entry, 16 years before Horrocks, is less forthcoming.  Under a column headed "Aprill 18 1616", is the following entry:

April 23 Samuel Foster ---------------------- X11d
     [i.e. 12 pence, admission fee for a sizar]

Like Jeremiah Horrocks (and later Isaac Newton at Trinity College), Samuel Foster was a sizar, paying reduced fees in return for performing menial duties in college, such as waiting at tables and emptying chamber pots.  There is no sign of a county of origin.  Two years before Samuel Foster, the register was signed by his brother:

May 28 Walter Foster ---------------------- 6s [?]
     [i.e. 6 shillings]

Intriguingly, it appears that Walter Foster was NOT a sizar.  It's intriguing to speculate whether or not Samuel had to dispose of the contents of his brother's chamber pot! Venn's directory of Cambridge alumni confirms the registration dates, and confirms Samuel Foster (and not Walter) as a sizar.  John Ward's history of Gresham College also includes Walter in the chapter on Samuel Foster; Ward lists Walter's admission date as May 24th 1614, and adds the intriguing detail that Walter was "previously at Oxford", so perhaps Walter was some years older than Samuel.
The admissions to Cambridge give several clues to Samuel Foster's circumstances.  The Foster family must have been relatively wealthy to be able send two children to university; but the fact that Samuel was a sizar suggests limits to the family wealth.  Speculatively, a professional family background such as lawyer, teacher or clergyman would not be inappropriate.

Teaching in Coventry
Typically, John Aubrey tells us that Samuel Foster was an usher, or assistant schoolteacher, in Coventry, without telling us exactly where or when.  The principal educational establishment in Coventry at the time was the school founded by John Hale in the reign of King Henry VIII, and named for him.  Unfortunately the archives of King Henry VIII School were destroyed, along with the rest of the school, during a German air-raid in 1941.  Rob Phillips, the assistant archivist at the school, was only able to offer a brief passage on Foster from a school history dated 1945.  This turned out to be a paraphrase of Aubrey's biography.  However, Mr. Phillips was able to offer some very useful background detail:
"I can tell you that Philemon Holland was Usher at the school from 1608 to 1628, after which he became Headmaster until 1629.  Therefore Samuel Foster must have joined the School, as Usher, no earlier than 1628."
I was able to find out a little bit more about the early history of King Henry VIII school from "Coventry, Its Histories and Antiquities", compiled by Benjamin Poole (Searle, 1871), which is in the Coventry City archives:
"In 1629, Mr. Phinehas White, who succeeded Philemon Holland, made an application to the council of the corporation for permission to employ an assistant at his own cost, in consequence of the extraordinary number of scholars..." (P 528)
So Foster may have been usher, or assistant teacher (these may have been separate posts) to Phinehas White.  Poole's book also clarified the structure of the school.  There were two departments - the usher's, or low school, and the headmaster's or high school. The headmaster received 40 pounds pa, the second master 20 pounds, the singing master and the bailiff 3 pounds pa each.  The school received 70 pounds annually in rental.
By 1629, Samuel Foster had already published his first work "The Use of the Quadrant" (1624).  I haven't yet seen this work and so I am not able to say if it contains any clues to Foster's location in the first half of the 1620's.
I am however able to locate Samuel Foster in the year 1635.  A Letter from M.J.Hinman, assistant archivist, Coventry City Council, indicated that the Coventry city archives contained multiple copies of a document dated Oct 1635, comprising surveys and acreages for Warwickshire and Coventry County by Samuel Foster.  The documents are titled:
"The Survey of Warwickshire, made by Mr. Samuel Foster October 1635"
One copy is titled "Mr. Samuel Foster, mathematician"
The content of the document is a laborious calculation of the acreage of Warwickshire, the acreage of the city of Coventry, followed by a long division which shows that the "...County of Warwick only, containeth the aforementioned plot of the city and count of Coventry 33 times and 4/5 parts of the aforesaid libertie of Coventry, which appeareth by this division". In other words, the county of Warwickshire was 33.8 times the size of the city of Coventry.

Gresham Professor of Astronomy
Foster's next move was to London. John Ward's biography continues: "His inclination led him chiefly to the mathematics, and upon the death of Mr. Gellibrand, astronomy professor in Gresham College, he was chosen in his room, upon the 2 March 1636; but quited the place again on the 25 of November following, and was succeeded by Mr. Mungo Murray."
Gresham College, in Bishopsgate, north of the city of London, was named for Sir Thomas Gresham, the founder of the Royal Exchange.  When Gresham died in 1579, he specified that, on the death of his wife, his estate should go to the city of London, for the establishment of a college to give public lectures to the people of London.  Lectures began in 1598; with professors of astronomy, geometry, law, physic, rhetoric, divinity and music, housed in his mansion and gardens in Bishopsgate.  Each professor was expected to lecture on a particular day of the week; in Latin in the morning, repeating the lecture in the afternoon in English.  Wednesday was astronomy day.
The Bishopsgate buildings are long gone, however the name of Gresham College lives on in a public education program run by the City of London, based at Barnard's Inn Hall.  The seven professorships remain, with the recent (1995) addition of an eighth Gresham Professor of Commerce.  Recent Professors of Astronomy include Roger Tayler (1969-75), Martin Rees (1975), Heather Couper (1993-96) and Colin Pillinger (1996-2000).  The current Gresham Professor is John Barrow, also of Cambridge University, a prolific author of popular science books.  John Barrow was one of my lecturers when I was a student at Sussex University.
Henry Gellibrand's main claim to fame was the recognition that compass needles dip (responding to the vertical component of the Earth's magnetic field); he also had interests in sun-dialling, but did not otherwise make great contributions to astronomy.  Contrary to the implication of Ward, Gellibrand was not replaced immediately after his death; elections were scheduled twice in February, but Foster was eventually elected ahead of two other candidates in March.
 So why did Foster give up his professorship within nine months?  John Ward says nothing about this, but a Ph D. thesis by Ian Adamson, held in the Cambridge University library, sheds very interesting light.  Dr. Adamson quotes a contemporary source, Johanne Hunneades, as saying "Mr. Foster our lecturer in Gresham College is put out because he will not kneel down at the communion table when he takes the communion".  In other words, Foster's non-conformist beliefs were a problem.  The minutes of Gresham College, Adamson tells us, that "he [Foster] thought it safest to resign".  These were dangerous times.  In particular, Archbishop Laud, tormentor of religious dissidents, had expressed his dislike on religious grounds of Foster's predecessor Henry Gellibrand.  Foster may have perceived similar criticism.
Dr. Adamson goes on to say that the College may have been grateful to receive Foster's resignation, as they were under some pressure from King Charles I to appoint Foster's successor, Mungo Murray, to "the reading of the Geometry and Astronomy lectures which (ever) shall fall first vacant and at the committee's dispose".  Mungo Murray, a Scotsman lately of Oxford University, was clearly a political appointment by the Royalists.  By all accounts he was not much use as a scientist.

Title page of Samuel Foster's "The Art of Dialling" (1638)

The Art of Dialing
I don't know for certain where Foster went to once he left Gresham College.  Ward tells us simply that "After the surrender of his professorship, he continued to pursue his mathematical studies".  However, I can tell you exactly where he was on September 21st 1637.  For the following year, 1638, Foster published his second and most important book, "The Art of Dialing".  This is a manual for the construction of sundials.  The title page advertises that the book shows "how to describe the Houre-lines upon all sorts of Plaines, Howsoever, or in what Latitude soever Situated".  This is achieved by the use of dialling scales, a computational device which Foster invented.
From the point of view of tracing where Foster was residing, the most important part of the "Art of Dialing" comes at the end, "An Appendix, shewing a ready way to find out the latitude of any place the Sunne... By the Meridian Altitude, and declination of the sun had; how to find the Latitude of the place, or the elevation of the Pole above the horizon." Finding the latitude of your location is vital if you want to align the gnomon of a sundial correctly and so use the sundial to tell the time accurately.  Foster recommended observing the altitude of the Sun above the horizon at mid-day (i.e. its highest point), and supplied a table of correction factors for the Sun's position along the ecliptic on every day of the year. He concluded the appendix with a worked example.
"... For example. Upon the 21 of September 1637, I observed the Sunnes altitude in the Meridian to be 34gr. 10 min. Upon which day I find that the Sunne's place to be (as before) 8gr. 23 min. of [symbol for Libra], and the declination of 3 gr. 20 min.  And because the Sun is in a south ligne, I add this declination and Meridian altitude together, the summe 37 gr. 30 min. is the altitude of the aequator, and this taken out of 90 degrees leaveth 52 gr. 30 min. for the Latitude of Coventrie. FINIS"
Interestingly, the latitude of Coventry is 52 degrees and 25 minutes; 52 degrees 30 minutes lies around 10 miles to the north.  This may be weak evidence that Foster was actually observing from a location north of Coventry (e.g. Newhall Green, at 52 degrees 28 minutes north) or it may be an imperfect observation, faithfully reported.  As we'll see, however, other latitudes mentioned in Foster's later work appear to be accurate to within one minute - so it's possible but by no means certain that Foster was observing from north of the city.

Observations from Distant Places
John Ward tells us that: "He made several curious observations of the Sun and Moon, as well as at Gresham College, as in other distant places (see his Miscellanies)."
The Miscellanies, or, "mathematical lucubrations", was a posthumous publication, consisting of a series of papers on varied topics, supplied after Foster's death, by his brother Walter Foster to his friend John Twysden, "a learned and scientific man who acquired great proficiency in astronomy as well as medicine".  The curious observations are in a paper entitled "Observationes Eclipsum" and consist of details on eight lunar eclipses, four solar eclipses, one comet, and one sun-spot, made during the period 1638-1652.  There is a problem.  John Twysden cheerfully admits in the introduction to the Miscellanies, "[to] the observations of some Eclipses, the motion of the late comet, with some other things, I have added my own, which being themselves not worthy of the presse, I made choice to hide under the shadow of so great a person".  So there is no way in some cases of telling which observations are by Foster and which by Twysden!
Fortunately, for the first lunar eclipse there can be no doubt that Foster was involved, as it was made "in the presence and with the assistance of John Palmer and John Twysden". Here is the beginning of the account:-
"The observation of the Moon's eclipse, which happened at New-hous near Coventry, the ninth day of Decemb. complete in the year 1638, 13h 58. after noon [ie 1:58 AM] In the presence and with the assistance of John Palmer and John Twysden.
Half her circle, that is to say 7 dig 1/4 , were darkened when Rigel was high 24 deg 58 1/2 m. The hour of the night 12g 45m.
Two thirds of her diameter, or eight digits, were obscured when Rigel was high 24 gr. 37 m., the hour of the night was 12 gr. 50m.
11/12 of the diameter was enlightened or 11 dig and some what more Arctur. high 31 gr. 56 1/2 min, the hour 3h. 45 min. Rigel was between South & West. Arcturus upon the eastern coast."

This time the latitude of Coventry is given as 52 degrees 29 min, still approximately 4 minutes north of the city's actual position. A named location of "New hous" is specified, however, and it is this that may have given rise to the assertion that Foster "lived in Newhall Green during the 1630's".

New House, Coventry as it appeared in 1702 (from the Illustrated History of Coventry's suburbs)

Detail from Henry Beigton's 1727 map of Warwickshire, showing New House to the north-west of Coventry

There is however a more likely possibility.  According to David McGrory's "Illustrated History of Coventry's Suburbs" (p. 91), a mansion called "New House" was built in 1586, two miles north-west of Coventry, in the area now known as Radford (at the current-day junction of Keresley Road and Sadler Rd).  The latitude of New House was only 51 deg 26 min - but whilst it is a considerable stretch to label Newhall Green as part of Coventry, New House fits that description much better.  New House was built on the site of Whitmore Park, a moated hunting ground of 436 acres presented by King Edward VI to Sir Ralph Sadler. Sadler sold the park to John Hales, the founder of King Henry VIII School, and Hales built New House, a fine domed and turreted mansion, leaving the rest of the park as a "wilderness".  The house remained in Hales's family until the early seventeenth century, although by 1640 ownership had passed to Sir Christopher Yelverton, baronet of Eston Maudinit, Northants.
Here is the clincher.  Christopher Yelverton, owner of New House, was married to John Twysden's sister Anne.  One can imagine Twysden, Palmer and Foster dining with Twysden's in-laws before going outside to the wilderness to observe the eclipse.
New House was demolished in 1778, and replaced by a smaller house.  By the 1920's nothing was left of the New House estate, and a housing estate was built on the site. Intriguingly, this includes a Foster Road, running parallel to Keresley Road, with a Yelverton Road nearby; Whitmore Park gives its name to another suburb just to the north.  I made a further enquiry to the Coventry Archives, and M.J.Hinman replied that "interwar Town Clerk Frederick Smith was a local historian who liked giving relevant names to new streets all over the city."  The connection to Samuel Foster is not certain (other roads in the area are named for nineteenth century novelists) but the presence of Sadler and Yelverton Roads certainly suggests a memorial to Whitmore Park and New House.
Samuel Foster and his friends were not the only people to observe the lunar eclipse of May 22nd 1638.  Jeremiah Horrocks observed it too, from Much Hoole.  Moreover, Horrocks had written to his cousin, Thomas, who had emigrated to the New World, asking him to observe the same eclipse from America, and note how many hours before dawn the eclipse finished.  Thomas observed the eclipse from Quidnick, Rhode Island, and sent his measurements back to England.  By comparing the timings of the eclipse from Quidnick and Much Hoole, Jeremiah Horrocks was able to work out (albeit with a large margin of error) the difference in longitude between the two locations.  This is arguably the first derivation of longitude of any place in America.

Further Observations by Foster and his circle
These are the other events listed (in similar detail to the New House eclipse) by Foster / Twysden:

Other lunar eclipses:

* The observation of the Eclips of the Moon, anno. 1641, made upon St. Mary hill neer the Tower in London, the eighth day of October about 8 at night.
* The observation of the Moons Eclips, as it happened at Aubrey in Somersetshire. The latitude of that village is 51 deg. 10 min, as it hath several times been observed by me.
* The Eclips of the Moon observed at London Anno 1643 Septem 17, between 7 and 8 after-noon. Latitude 51 deg. 30 min
* The Eclipse of the Moon observed at London An. 1645 Janu 31 upon Friday, between the hours of 7 and 9, at night. The latit 51 deg. 30m.
* Eclipsi Lunae observata London: 1649, May 15
* An Eclips of the Moon observed at Gresham Colledge
* The Moon's Eclips observed as it happened at Easton in Northamptonshire, March the 14th, 1652 about three of the clock at night.. Latitudo 52 gr. 15 min, A Joh Twysden & Joh Palmer.

The track of the 1639 solar eclipse, and the appearance of the sun from Coventry on June 1st 1639 (May 22nd 1639 Old Style)

Solar eclipses:

* The Eclips of the Sonne which happened May 22 P.M. 1639, observed in Old Bayly in London A Samuele Foster & Joh Twysden. The latitude of London is 51 deg. 32 min. for so others and we have observed it.
* The Eclips of the Sun observed in London August 11th, 1645
* The Eclips of the Sun 1649 October 25th afternoon, observed at Gresham Colledge in London.
* The Sun's Eclips, observed at London 1652, March 29, before noon.
* The Sun's Eclips observed at Easton in Northamptonshire 1652, March 29 current, about 9 in the morning Lat. 52 gr. 15 min. (note same eclipse as previous)

Easily the best of the solar eclipses was March 29th 1652, "Mirk Monday", which was total in lowland Scotland and the eastern coast of Ireland. According to one contemporary source "the country people tilling, loosed their ploughs.  The birds dropped to the ground".  The eclipse of May 22nd 1639 was annular from Scandinavia, and was > 70% throughout England (I'm grateful to Sheridan Williams for supplying an eclipse track and maximum eclipse from Coventry).

Other observations:

* The motion of the late Comet as it was observed at Easton in Northamptonshire Anno 1652, Lat 52 d. 15m.
* "Upon Tuesday the second of July in the year 1651, about eight of the clock at night, at Easton in Northamptonshire, under the elevation of the North Pole 52d. 15 min., I saw in the body of the Sun (through an excellent Tellescope whose Glasses were very clean) a very dark round spot in diameter about 12 part of the Sun's diameter..."

Some notes:

* Easton (elsewhere Eaton and Ecton) was a village to the east of Northampton, where John Palmer became rector in 1641.  Its latitude is indeed 52 deg. 15 min. John Palmer later became deacon of Northampton.  Both his son and grandson became rectors of Eaton.
* The Somersetshire location of Aubrey may be connected with Walter Foster, who had become rector of Allerton, Somerset.
* The latitude of Bishopsgate was around 51 deg. 32 min.  The centre of the city of London is closer to 51 deg. 30 min.

I want to pause here and point out how unusual such detailed observations were during the first half of the seventeenth century, within fifty years of the invention of the astronomical telescope.  At this time there were no Royal Observatories, no Astronomers Royal.  There were exactly two salaried astronomers in England; the Gresham Professor Mungo Murray, a non-entity appointed for political reasons, and John Bainbridge, the Emmanuel man, who held the newly established Savilian Professorship of Astronomy at Oxford University.  I know of only two groups of serious observational astronomers in England at this time - Jeremiah Horrocks, William Crabtree, William Gascoigne and others in the north of England, and Samuel Foster, John Twysden, John Palmer (and possibly Nathaniel Nye, see below) observing from the Midlands and London.
The eclipse of May 22nd 1639 was observed by Horrocks and his colleagues in the north-west. William Crabtree wrote to William Gascoigne, inventor of the micrometer, "You shall also have my observations of the Solar eclipse here at Broughton, Mr. Horrocks between Liverpool and Preston, and Mr. Foster in London".  So, in the year that Horrocks and Crabtree observed the Transit of Venus, the two groups of astronomers were exchanging observations - and, as we have seen, Horrocks attempted to warn Foster about the upcoming Transit.
At this point, if I was any use as a historian, I would produce a previously unknown document detailing Samuel Foster's observations of the 1639 Transit of Venus, preferably from in front of Coventry Cathedral.  Unfortunately this is unlikely to happen, as I do not believe that Samuel Foster ever did see the Transit.  We don't know, for example, that William Crabtree did pass on Jeremiah Horrocks's information to Foster.  He may not have had time, and even if he did, there is no certainty that he knew Foster's location.  We know that Samuel Foster was in Coventry on Sep 21st 1637, and on Dec 9th 1638, and in London on May 22nd 1639.  If he had returned to Coventry for the latter part of 1639 it is unlikely that a letter from Crabtree would have reached him in time.
Moreover, as we'll see later, Foster had strong connections to the Royal Society.  Horrocks's observations of the Transit came as a complete surprise to the Royal Society when they were published by Hevelius several years after both Horrocks's and Foster's death.  Any observations of the Transit of Venus by Foster would surely have been known to people such as John Wallis, who knew both Foster and Horrocks.

Nathaniel Nye
I wanted to make a brief diversion to point out a possible collaborator of Foster, and yet another Coventry observer.  Nathaniel Nye, author of the "Art of Gunnery", a classic military text of the English civil war, described in one of his early works "observations by me and others of my friends made at Coventry" which included a solar eclipse in 1640, when he was only around 16 years old.  This potentially made him a student of Samuel Foster.

The frontispiece of Nathaniel Nye's "The Art of Gunnery" showing the author, who claims to have seen an eclipse from Coventry in 1640

However, there are some peculiarities.  Foster and Twysden do not mention Nye in any of their eclipse descriptions.  Moreover, although there were two solar eclipses between January 1st 1640 and March 25th 1641, neither was visible from England (perhaps Nye viewed the very good solar eclipse of May 22nd 1639, and misremembered the year). Furthermore, although Nye described himself as a mathematical practitioner and astronomer, he actually had limited knowledge of astronomy - I have read, for example that he thought that the Moon was bigger than the Earth.  This is an opinion Foster could easily have disproved to him; Foster's own calculations in his mathematical lucubrations, "An epitome of Aristarchus Samii, Proposition XVII", show that the Moon's diameter is 20/57th (0.351) that of the Earth. The actual ratio is 0.272.
Frustratingly, although I have been able to read "The Art of Gunnery", which is a purely military manual, I haven't been able to locate a copy of the almanack in which he makes his astronomical claims.  Without more substantial evidence, I'm inclined to think that Nye was a peripheral figure in Samuel Foster's circle.
Curiously, however, later in his career Foster did have a student who was also a gunner - Thomas Rice, who was gunner in the Tower of London.  By then Samuel Foster had been re-elected to the Gresham Professorship.

A return to Gresham College
By 1641, Mungo Murray was becoming an embarrassment to Gresham College. Fortunately, perhaps, the College were "credibly informed" that he had neglected to inform them that he had got married, in violation of the statutes of the college.  Moreover, Archbishop Laud had been impeached in 1640 and was now in the Tower of London.  John Ward simply reports that the "professorship being vacant again by the marriage of Mr. Murray, he [Foster] applied for it, and was rechosen May the 26th of that year."
As we've already seen, Foster and his colleagues John Palmer and John Twysden were engaged in a program of observation and measurement (I'm assuming that the London observations were primarily by Foster, and the Northampton observations by Palmer).  The esteemed instrument maker Anthony Thompson was also based at Gresham College and provided Foster with quadrants and other instruments built to Foster's designs.  In addition to his weekly lecture commitments, Samuel Foster engaged in research into a wide variety of topics.  Foster's miscellanies include a catalogue of star positions; a comparison of the relative sizes of Sun, Moon and Earth; and a table of sinusoidal values, from which Foster deduced a value of pi accurate to 10 decimal places (but wrong for a further 5 digits). Foster's comments on the "New Astronomy" are of interest - in one paper, on "how the theorie of the planets are made", he explains "The way I goe is (in general) agreeable to Copernicus his frame of the world; and in particular, to that which Kepler useth in his Rudolphian tables.  Onely this difference there is: Kepler makes the Orbits of the Planets to be Ellipses, which is the better way, and I here doe make them to perfect circles, which is the easier way".  This explains perhaps why Horrocks and not Foster predicted the Transit of Venus.
The better part of Foster's researches, however, were in spherical trigonometry, in particular the mathematics of dialling, or the efficient and artful construction of sundials. Unfortunately ill-health prevented him from publishing most of this work during his lifetime. The only work Foster published whilst he was Gresham Professor was a work on spherical trigonometry, sent to and published by John Wallis.
Four treatises of dialling were published posthumously in 1654:
Elliptical or azimuthal horologiography
Circular horologiography
Rectilineal or diametrical horologiography
Elliptical, by spherical and not projective horologiography

There were two other posthumous works: "Posthuma Fosteri - containing the description of a ruler, upon which are inscribed divers scales, etc." (published 1652), and "The sector altered and other scales added, with the description and use thereof." (1672).  All these works were published by William Leybourne.
I've read (well, skimmed through) the four treatises on dialling (all four are in a single volume in Emmanuel College library, bound with a number of other eclectic tracts by other authors, such as "The Spanish Grammar", "The Seaman's Dictionary" and "A Treatise on Continual Motion").  I don't pretend to understand the detail of Foster's dialling; fortunately I have been in email contact with Fred W. Sawyer III, of the American Sundial Society, who has written extensively on Foster, and has provided me with a great deal of information on the mathematics of Foster's dialling.  I'll give two examples of what Foster achieved in the field of dialling.
Although he wasn't the first to think of the idea (M. de Vaulezard of Paris first suggested the concept in 1640), Samuel Foster greatly developed the mathematics of analemmatic sundials.  These are dials where the hours are spread out evenly around a circular dial, just like a clock face.  For ordinary sundials this cannot work, as the gnomon's shadow's progression around the dial depends on hour and on season.  However, in an analemmatic dial, the position of the gnomon changes day by day, in such a way as to ensure an even progression of the shadow.  The easiest way to manufacture such a gnomon is to leave the job to the observer, and so analemmatic sundials often come with instructions as to where the observer should stand so that their own shadow tells the time.  I know of one such sundial in the Coventry area, the sun clock at Ryton Gardens (the Henry Doubleday Soil Research Association).  There's also one at the Norman Lockyer Observatory in Sidmouth, Devon.
A second mathematical construction employed by Foster was the nomogram, a calculating device consisting of a circle divided in two, with one quantity on one semi-circular arc, a second quantity on the other semi-circle, and a third along the diameter splitting the two. Place a ruler across the circle, and the three points it crosses will be in the required mathematical relationship. (See diagram).  The interesting thing about nomograms is that some authorities date their development to 1905 - some two and a half centuries after Samuel Foster.

I will conclude my brief summary of Foster's dialling career with some thoughts on his most famous sundial, as described by John Aubrey, "the best sundial I do verily believe in the whole world. Among other things it shows you what o'clock 'tis at Jerusalem, Gran-Cairo etc.".  I was intrigued what such a dial looked like.  John Ward's history of the Professors of Gresham College has an engraving indicating how the college appeared in 1740, and I searched it fruitlessly for a view of the sundial.  I was even more intrigued to discover a sundial, erected in Rugby, and dating from around 1630, which naively appeared to meet Aubrey's description.  However I've yet to find any direct connection to Samuel Foster.

"We did by agreement, divers of us, meet weekly"
The 1640's were hardly an ideal time for scientific studies, as England lurched into civil war. For example, John Aubrey reports that William Gascoigne "was killed at the battle of Marston Moor, aged 24 or 25 at most".  Nathaniel Nye supervised the defence of Worcester and planned the fortification of Birmingham and Coventry.  Mungo Murray was caught in possession of a letter from King Charles to the French ambassador in Scotland. John Wallis deciphered Royalist codes for the parliamentarians.
Fortunately, Gresham College was relatively unaffected.  John Ward tells us that "...upon the breaking out of the national troubles, which soon followed his [Foster's] return to Gresham College, he was one of that worthy and learned society of gentlemen, who met in London for cultivating the new philosophy, of which an account has been given in the preface."
The account is by John Wallis: "About the year 1645 while I lived in London, I had the opportunity to be acquainted with divers worthy persons, inquisitive in natural philosophy, and other parts of human learning, and particularly what hath been called the new or experimental philosophy.  We did by agreement, divers of us, meet weekly, on a certain day, to treat and discourse of such affairs.  Of which number were Dr. John Wilkins, afterward bishop of Chester, Dr. Jonathan Goddard, Dr. George Ent, Dr. Glisson, Dr. Merret, doctors in physic; Mr Samuel Foster, then professor of astronomy at Gresham College; Mr Theodore Hank, a German of the Palatinate, and then resident in London (who, I think, gave the first occasion, and first suggested the meetings) and many others. These meetings were held ...sometimes at Gresham College"
These meetings, sometimes at Gresham College (by implication, in Foster's rooms) led directly to the formation of the Royal Society in 1660.  In the more relaxed years of the Restoration, the Royal Society prospered immediately, providing the stage on which the greats of British Science - Newton, Hooke, Boyle, Halley and many others - were able to flourish.  Unfortunately, Foster did not live long enough to see the foundation of this most eminent of societies.  Ward tells us that he was "disabled by his great and long infirmities" during his professorship, and in 1652 Foster succumbed. Samuel Foster was buried at the church of St Peter le Poer in London.
Samuel Foster's will still exists.  I haven't seen it, but Fred Sawyer was kind enough to provide details.  Foster left 80 pounds to Martha Beyes, (probably) mother of the watchmaker who provided Aubrey with biographical details.  He also left 80 pounds jointly to his cousin Thomas Martin and to John Palmer, to be used for the benefit of his sister Elizabeth Poyner.  Foster says in his will "I would have given her as much as to ye rest, but ye wickedness of her husband is such, that what ever shee hath, he will spend, therefore I give her nothing at all".  Foster left Palmer and Martin twenty shillings each to purchase a book or whatever else would please them.
Over the next few years, John Twysden and Foster's lawyer Edmund Wingate presided over the publication of many of Foster's works.  There was an urgency to this: John Ward reported Twysden complaining that "some persons having got into their hands some things of Mr. Foster's, which out of that diffusive goodness and candour of disposition, that was in him, he communicated to others; had under a disguised face vented them as their own". Foster, don't forget, had been lecturing on astronomy at Gresham for eleven years, barely publishing anything.  There must have been a great temptation after Foster's death for his students to publish his work with minimal or no attribution.  Conversely, Twysden also took the opportunity to attach Foster's name to his own observations and discoveries, perhaps to add some authority.  For example, Emmanuel College library contains a work on Reflexive Dialling (i.e. mirror-based sundials) which is indexed as being by Foster; but an inspection of the text reveals that the work is actually Twysden's.

As with many figures from the seventeenth century, some much more famous than Samuel Foster, there are a great many questions still remaining in his life, not least most of the ones I set out to answer.  Where was he born?  What was his family background? How strong were his ties to Coventry?  I have perhaps provided a few more clues, but I'm sure there is more evidence to be uncovered.
It would be wrong to over-emphasise Samuel Foster's contribution to the history of astronomy.  He was a competent but not a great observer.  Although he appreciated the importance of Kepler's "New Astronomy", he did not master Kepler's theories well enough to be able make discoveries of his own, in contrast to his correspondent Jeremiah Horrocks.  Foster's major theoretical contribution was to the theory of sundials, something of a backwater in the river of astronomical history.  Yet it was in this subject that he made his most impressive contributions, and I think he deserves to be remembered for his developments of spherical trigonometry, particularly his invention of the nomogram.
Finally, I was surprised and rather proud that so many of the people covered in this account - Samuel Foster, Jeremiah Horrocks, John Palmer, John Bainbridge, John Wallis - were educated at Emmanuel College.  Quite why one small establishment should be so productive during this period is a matter for conjecture, especially as the Cambridge curriculum contained almost no astronomy at the time.  I put forward the thesis that the independence of thought and intellectual courage demonstrated by non-conformist thinkers in such troubled times were exactly the skills needed to understand and develop the new astronomy.

Ryton Sun Clock - an analemmatic sundial at Ryton Gardens, near Coventry and the instructions on where to stand


I'm especially grateful to:

Fred Sawyer, of the American Sundial Society, who provided a large amount of material on Foster, both biographical and on the mathematics of sundials.

Chris Hicks, a colleague at work, who provided much useful information about Foster's family background.

Sheridan Williams, author of "UK eclipses from the Year 0", for checking the circumstances of solar eclipses in 1639 and 1640.
I also gratefully acknowledge the assistance of the following establishments:

Warwickshire County Record Office (G.M.D. Booth)
Northamptonshire County Record Office
Coventry City Archive (M.J.Hinman)
Emmanuel College Library (Helen Carron, Janet Morris)
St John's College Library (Jonathan Harrison, Alan Purviz)
Cambridge University Library (Adam Perkins)


Primary Sources:

Emmanuel College register for 1614 and 1616.
Cambridge University matriculation register for 1614 and 1616
"The Art of Dialling" Samuel Foster (London 1638) - Emmanuel College library
"Elliptical or azimuthal horologiography", "Circular horologiography", "Rectilineal or diametrical horologiography", "Elliptical, by spherical and not projective horologiography", Samuel Foster (London, 1654) - Emmanuel College library
"Miscellanies, or mathematical lucubrations" Samuel Foster, ed. John Twysden (London, 1659) - St John's College library, by kind permission of the Master and Fellows of St John's College, Cambridge.

Near Contemporary Sources:

"The Art of Gunnery", Nathaniel Nye
"Brief Lives", John Aubrey (Originally published 1680; this edition ed. Richard Barber, First Person Singular, 2004)
John Ward's "Lives of the Professors of Gresham College" (1740) (Cambridge University Library)

Secondary Sources:

Dictionary of National Biography, entries on Samuel Foster, Nathaniel Nye, John Wallis
Venn, Dictionary of Cambridge Alumni
Taylor, Dictionary of Oxford Alumni
"Coventry, Its Histories and Antiquities", compiled by Benjamin Poole (Searle, 1871)
"The Transit of Venus - The Brief, Brilliant Life of Jeremiah Horrocks, Father of British Astronomy", Peter Aughton (Weidenfeld & Nicolson, 2004)
"A History of Emmanuel College Cambridge", Sarah Bendall, Christopher Brooke & Patrick Collinson (The Boydell Press, 1999)
"Jeremiah Horrocks, the Transit of Venus, and the 'New Astronomy' in early seventeenth-century England", Allan Chapman (Q. J. R. Astro. Soc. (1990), 31, 333-357)
"The foundation and early history of Gresham College, London, 1596-1704", I.R.Adamson (Cambridge University PhD, 1976)
"The Illustrated History of Coventry's Suburbs", David McGrory (Breedon books, 2003)
"The Mathematical Practitioners of Tudor and Stuart England", D.G.R. Taylor (C.U.P. 1954)
"The 1996 Andrew Somerville Memorial Lecture - Samuel Foster of Gresham College", Frederick W. Sawyer III (British Sundial Society Bulletin 97.1, Jan. 1997)
"Foster's Proof for Dialling Scales", Fred Sawyer (NASS Compendium, Vol 8 No 2 pp 28-31, June 2001)
"The Further Evolution of Samuel Foster's Dialling Scales", Fred Sawyer (NASS Compendium, Vol 8 No 3 pp 28-31, September 2001)
"The Foster-Point Sundial: Time in a Perfect Round"
, Fred Sawyer (NASS Compendium, Vol 8 No 3 pp 14-16, September 2001)
"Regulating the Foster-Point", Fred Sawyer (NASS Compendium, Vol 8 No 4 pp 7-9, December 2001)

A Rugby Sundial

By Mike Frost

Some time before I started investigating Samuel Foster, I came across a news item in the Rugby Observer, dated Thursday July 22 2004, which I filed for future interest.
"A historic sundial has been restored to its former glory to become the centrepiece of Lime Tree Village.  The sundial was made in 1861 as a tribute to Lord John Scott, who built Cawston Lodge, which is part of the retirement village, in the 19th century.  It is an exact replica of a 16th century sundial at the Palace of Holyrood in Edinburgh, which was commissioned for the coronation of Charles I in 1633.  It was unveiled at its new home by Frederick Fernden, who is a member of the British Sundial Society".
Cawston House is to the west of Rugby, less than two miles from where I live in Bilton.  Lime Tree Village is a specially built estate, specifying a minimum occupancy age of 55.  I could retire there in another 11 years! 
I was mildly interested but not interested enough to go and photograph the sundial - until I started to research Samuel Foster.  I rapidly came to realise that one of the most important figures in the history of dialling had been living in Coventry, at exactly the time the original of the sundial was build in Edinburgh.  So could Foster have had anything to do with the design?  Was a copy of one of Foster's sundials sat in Rugby?
I paid a visit to Cawston one Saturday afternoon, and took some photographs.  The dial consists of a stone column, with an ornate carved snake wrapped around it.  On top of the column is a plinth, bearing an inscription "John and Alice Scott, United in Time".  On top of the plinth sits a stone polyhedron.  On the faces of the polyhedron are a number of dials, each with an ornate metal gnomon.
The presence of a number of dials struck me as being reminiscent of Aubrey's description - "Among other things it shows you what o'clock 'tis at Jerusalem, Gran-Cairo etc."  (although on further thought, you could probably get away with only one dial, with different scales for each city).  Furthermore, 1633 was a little early in Foster's career.  He wasn't yet Gresham Professor, and he had only published one work.
There was only one to find out for certain.  I emailed Holyrood Palace. Graeme Fairbrother wrote back to me to say: "The sundial in the north garden of Holyrood Palace was constructed in 1633 by John Mylne for Charles I and restored during the reign of Queen Victoria. The head is a polyhedron with heraldic devices carved on the facets." 
Regrettably, there is no sign that Foster was involved.

The sundial at Cawston House, a copy of the 1633 sundial at Holyrood Palace