Monthly Archives: November 2019

A revolutionary new year

Two intriguing maps of the Channel, both with something special about them.

The first uses hachures (lines on a map to indicated hill slopes) around the coasts which has effect of making the land stand out.

The effect is lovely even if not representative of the actual height of land. The map, titled ‘3d [as in third] chart of the coast of France, including the British Channel’ and comes from ‘Le Petit Neptune Français; or, French Coast Pilot, for the coast of Flanders, Channel, Bay of Biscay, and Mediterranean’, published in 1793 by W. Faden, Geographer to his Majesty and to his Royal Highness the Prince of Wales. The book was published 4 years after the start of the French Revolution and just a year after the new French Republic was founded. Despite this the book has an innocent intent, a Coast Pilot is an aide for navigation and sailing and this map includes the familiar rhumb lines and compass rose that are found on sailing charts, and there seems to be no mention of any danger in sailing around and into France along the tidal rivers in the book.

The Paris Observatory is shown, an important building at a time when France was one of the leading cartographic nations. The building pre-dates the Greenwich Observatory and was the site of the Paris Meridian, which has in the past competed with Greenwich to be the main meridian. The map also features along the bottom of the page a cross-section of the land in relation to the sea floor between the Isles of Sicily and Orford Ness.


A French alternative to the Faden map is a map of the Channel by the French ‘Ministre de la

Marine’. What is interesting about this map is the dates given, ‘ I’ An VII de la République, nouvelle edition de I’ An XI’. Following the start of the Revolution a new way of recording  years was implemented but as this introduced towards the end of 1793 there is no year one, year two goes from 22nd September 1793 to 22nd Sept. 1794 with the years numbered after this. Our map, ‘Carte réduite de La Manche’, was first published in year VII (1799) and then reprinted in XI (1802), during the planning and build up of resources for a possible invasion of Britain by Napoleon which was called off in 1805. It is one of the few maps in the library dated this way.

The map has seen better days, as can be seen be this burn mark just above Rouen.

Le Petit Neptune Français; or, French Coasting Pilot…’ 1793. W. Faden Vet A5 d.570.

Carte redutie de La Manche… 1802. (E) C2:5 (34)

Heliometer Domes and OS maps

The Ordnance Survey 1:500 map series are amongst the most detailed of all town plans. Dating from the 1880s and covering all towns with a population over 4,000, at this scale roofs come off important buildings to show the layout of the rooms underneath. While going through the maps covering Oxford this intriguing building appeared, the Heliometer Dome, part of the Radcliffe Observatory buildings.

The Observatory moved to Pretoria in 1934 hoping for clearer skies than could be found in Oxford, the buildings are now part of Green Templeton College. As well as showing on a beautiful map the Heliocentre has other cartographic claims for appearing in a map blog as it was a device crucial for measuring distances in space. The telescope in the Heliometer has a split lens, one of which is fixed in position, the second adjustable, thus producing a double image of either nearby stars or either sides of the Sun. By moving one of the lenses these images can be superimposed and then the different lengths of the lenses can be measured which will give the difference in distances between stars, a concept called parallax.

The Heliometer Dome circa 1860.

This next map is an extract from Robert Hoggar’s celebrated map of the city from 1850. At a scale slightly less detailed then the Ordnance Survey (1:528 as opposed to 1:500) at the top of this blog, like the OS map Hoggar maps individual trees and outbuildings, unlike the OS Hoggar includes contour lines.

Plan of the City of Oxford. 1850 (E) C17:70 Oxford (1)

This last image is the front cover from a record of the magnitude of stars according to their observable light recorded at the Observatory in 1853.

We’ve blogged about Parallax before  and about Ordnance Survey 1:5000 town plans as well