Research Notes


Map Group HALLEY 1715
Halley 1715
MAP of the ECLIPSE by HALLEY, 1717
These notes are made from a map predicting the track and time of the shadow of an eclipse of the sun across England and Wales, by Edmund Halley, engraved and published by John Senex, London, 1717. The notes are made from a small reproduction of the map in:-
Shirley, Rodney W: 1988: Printed Maps of the British Isles 1650-1750: Map Collector Publications & British Library:: ISBN 0 7123 0142 9
Copies of the map are known:- Bodleian Library, Hearnes Diaries 53 p.137; Royal Astronomical Society Library.
The map size is wxh = 235x395mm.
This is one of the earliest scientific thematic maps.

Remember that these notes are strongly biased toward a Hampshire interest.
MAP FEATURES
THE ECLIPSE
REFERENCES
MAP FEATURES
title    
engraver    
publisher    
Printed at the top is:-
A Description of the Passage of the Shadow of the Moon over England, In the Total Eclipse of the Sun, on the 22d day of April 1717 in the Morning.
Printed lower right:-
Engrav'd by John Senex
and printed at the bottom:-
Sold by J. Senex at the Globe in Salisbury Court near Fleet Street; who also makes and sells ye newest and correctest Maps, and Globes of 3, 9, 12 and 16 Inches Diameter, at modest Prices Sold also by William Taylor at the Ship in Pater Noster Row.
orientation    
up is N    
The maps orientation is implied by the latitude and longitude scales. It is printed with North at the top of the sheet.

scale line    
There is a scale line printed upper right:-
A Scale of 60 computed Miles
The first 10 miles is chequered in miles, then the scale has graduations and labels at 10 miles intervals.

lat and long scales    
The borders of the map are printed with scales of latitude and longitude for a trapezoidal projection; chequered at 5 minute intervals, labelled at 1 degree intervals. The map includes from 1d 50m E to 6d 20m W, from 49d 55m to 56d 20m N; all of England and Wales, Scotland to north of the Firth of Forth, and the edges of Ireland and France.

Hampshire Places
On this small map, a limited number of settlements are marked and labelled; and on the smaller reproduction the place names are fairly illegible! The places relevant to Hampshire are listed below. There are unreadable places which are not listed.
         
place   map name    
         
Andover   [And.]    
Winchester   Winchester    
Southampton   Southampton    
Portsmouth   Portsmouth    
Christchurch   [Cst. Church]    
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THE ECLIPSE
The track of the eclipse is a straight line from about 5d 35m W, 49d 53m N just after 5 minutes past 9, to 1d 55m E, 53d 59m N at just before 19 minutes past 9. The line is marked with the time of the maximum eclipse:-
Minutes past Nine at London
Either side of the line the map is shaded to show where will see a total eclipse, about 75 miles wide. This track includes all of Hampshire.
The map was made before the event; it is predictive, science at its best. Edmund Halley wrote descriptive notes printed at the bottom of the map:-
The like Eclipse having not for many ages been seen in the Southern Parts of Great Britain. I thought it not improper to give the Publick an Account thereof, that the suddain darkness, wherein the Stars will be visible about the Sun, may give no surprize to the People, who would, if unadvertized, would be apt to look upon it as Ominous, and to Interpret it as portending evill to our Sovereign Lord King George and his Government, which God preserve. Hereby they will see that there is nothing in it no more than Natural, and no more than the necessary result of the Motion of the Sun and Moon; And how well those are understood will appear by this Eclipse.
According to what has been formerly Observed, compared wth. our best Tables, we conclude ye Center of ye Moon's shade will be very near ye Lizard point, when it is about 5 min: past Nine at London; and that from thence in Eleven minutes of Time, it will traverse ye whole Kingdom, passing by Plymouth, Bristol, Glocester, Daventry, Peterborough & Boston, near wch. it will leave the Island: On each side of ye Tract for about 75 Miles, the Sun will be Totally darkned, but for less and less Time, as you are nearer those limits, wch. are represented in ye Scheme, passing in ye one side near Chester, Leeds, and York; and on ye other by Chichester, Gravesend, and Harwich.
At London we Compute the Middle to fall at 13 min: past 9 in ye Morning, when 'tis dubious whether it will be a Total Eclipse or no, London being so near ye Southern limit. The first beginning will be three at 7 min: past Eight, and ye end at 24 min: past ten. The ovall figure shews ye space ye Shadow will take up at ye Time of the Middle at London; And its Center will pass on to ye Eastwards, with a Velocity of nearly 30 Geographical Miles in min: of Time.
NB. The Curious are desired to Observe it, and especially the duration of Total Darkness, with all the care they can: for thereby the Situation and dimensions of the Shadow will be nicely determined; and by means thereof we may be enabled to Predict ye like Appearances for the future, to a greater degree of certainty than can be pretended to at present for want of such Observations.
By their humble Servant Edmund Halley.
Calculations made by William Whiston to accompany the map were also sold by John Senex. The map was advertised in the London Gazette:-
This Day is Published a new Edition of Mr. Professor Halley's Description of the total Eclipse of the Sun on Friday the 22d Day of this Instant April in the Morning, when by reason of the sudden darkness the Stars will be visible about the Sun, the like Eclipse having not been seen in the Southern Parts of Great Britain for above 50 Years. N.B. The Map shews every part of England over which the total Darkness will pass, and may be sent by Post for the same Charge as a single letter ...
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REFERENCES
Thrower, Norman: 1978: Edmund Halley and Thematic Geo-Cartography: Compleat Platt Maker:: pp.225-227
Halley, Edmund: 1715:: Philosophical Transactions
Shirley, Rodney W: 1988: Printed Maps of the British Isles 1650-1750: Map Collector Publications & British Library:: ISBN 0 7123 0142 9
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