The Canary Island and the question of the Prime Meridian: the search for precision in the measurement of the Earth

              THE CANARY ISLAND AND THE QUESTION OF
THE PRIME MERIDIAN: THE SEARCH FOR PRECISION
IN THE MEASUREMENT OF THE EARTH
Wilcomb Washburn
The prime or first meridian @rimas meridianas) is an arbitrary line,
one from which chart makers and map makers can begin to measure and to
count longitudinal distance on the face of the globe. The system of deter-mining
terrestrial location by latitude and longitude measurements goes
'Da& to the GreeK mathematicians and geographers, Eratosthenes and Hip-parchus,
and was first incorporated in a form that has come down to us in
Ptolemy's Geography. Although Ptolemy's astronomical work was conduct-ed
in Alexandria, he chose the Fortunate Islands (the Canaries) as the phy-sical
location of the prime meridian from which point he measured and laid
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UVWII UIC. IUUSAIX~ 1"" "1 LIIC W V ~ I U n u u w u LV LMC. a u u u l L J . I LVICIIIY S jXi-pose
was to create an accurate grid system upon which the location of indi-vidual
cities from the furthest known land west to the furthest known land
east could be accurately placed. Unfortunately (or rather fortunately, as far
as Columbus was concerned), Ptolemy exaggerated the eastward extension
of Asia so that, even though he placed the Canarias about seven degrees too
far east, he reduced the distance a mariner would have to sail between west-ern
Europe and eastern Asia to what Columbus regarded as a manageable
distancel. The distance between those points -the extent of the unknown
world- was a matter of critica1 importance to Columbus. It is not surpris-ing,
therefore, that Columbus should have taken off from the Canaries in
his voyages across the unknown. (This is not to ignore the importance of the
prevailing wind patterns, nor is it to ignore Columbus's possible romantic
interest in Doña Beatriz de Peraza y Bobadilla as additional reasons for be-ginning
his four voyages in the Canaries.)
1. Wilcomb E. WASHBURN, eJapan and Early European Mapsn. Pacific HictoricalReview,
Vol. XXI, No. 3 (August. 1952), pp. 221-236; Emerson D. FITE and Archibald FREEMAN,
comp. and ed., A Book of OZd Maps Delineating Amencan Histoy from tbe Earlzest Days
down to tbe CLose of tbe Revolutionay War (Cambridge: Harvard Univenity Press, 1926, re-prinred
New York: Arno Press, l969), pp. 1-2.
The need for precision in determining the longitude of the lands in
the Ocean Sea to the west of Europe was emphasized by Pope Alexander
VI'S 1493 bu11 laying down a line of demarcation between authorized Span-ish
and Portuguese discoveries 100 leagues west of the Azores and the Cape
Verde Islands. After protests by Portugal, this h e was shifted in accordance
wiht the provisions of the Treaty of Tordesillas between Spain and Portugal
to a meridian 370 degrees west of the Cape Verde Islands2. The controversy
over where the h e fe11 -on both sides of the world- bedeviled relations
between the two powers for over a century.
When Colurnbus passed the point of no magnetic declination in the
ship's compass, he started cartographers on a vain quest for a stable isogonic
zero meridian -or line showing no magnetic variation. Many cartographers
";n' + "h'.e,& yír=en+hr en+,~t.xhi~ s-ron+ n mtn t h n~r ; rnm~+ r;A;om thrniirrh ttke A?-- "'^'Lb""' ""'"'J v L 6 - X 'V '"" "'" y""'L "'"'I"'U" '-"'Vyj" L"" ""V
res rather than through the Canary Islands. By mid-century, Mercator had
abandoned the Ptolemaic prime meridian in favor of a meridian based on
the point at which the compass showed no variation. This line was not
certainly established. In Mercator's 1554 map of Europe the prime
merirlian is will -I-n-r-a-t-d- npar -A--- -F errn t-h-e-- w. . esternmnw ------A-----u ^f the -A-- f anary TclonJc
but many map makets ran the new prime meridian through the Azores, as
did Hondius in his 1601 terrestrial globe, «because there the compass need-le
points due north», as he noted in an inscirption on the globe.
But it was increasingly apparent that the line of no magnetic variation
was not consistent with a true meridian. The search for precision led once
more to the Canaries. Johan Blaeu, on his 1622 globe, noted in an inscrip-tion
that the search for a meridian throuth the compass needle was «a delu-sion
» proved by the fact that «it varies along the same meridian according as
it is near one land mass or anothem. Therefore,
we, following in the steps of Ptolemy, have chosen the same islands and in
them Juno, commonly called Tenerife, whose lofty and steep summit covered
with perpetual cloud, cailed by the natives El Pico, shall mark the prime me-ridian.
In that way we have differed barely a quarter of a degree from the lon-gitude
of the Arabs who chose the extreme western shore of Africa,. . .
2. Derek HOWSE, GreenuiGh Time lzndthe Di~cove~oyf the Longitlrde (Oxford: Oxford
University Press, 1980). p. 127; LucieLAGARDE, ~Historiqude u problerne du Méridien origine
en Francen, Revm d'histoire des sciences et de leurs applications, Vol. 32 (Paris, 1979), 289-
304, ar 291.
According to the English scholar W.G. Perrin, «Here we have what
appears to be the first attempt to fix the meridian as passing through a pre-cise
geographical spot instead of vaguely through an island or group of is-lands
»3. In Blaeu's Le GrandAtGas (Amsterdam 1663, facsimile edition in
12 volumes, Theatrum Orbis Terrarum, Amsterdam, 1967), in Chapter
VI11 Blaeu discusses the uncertainly and lack of agreement over the place-ment
of the prime meridian, some following Ptolemy, some rhe marine
compass's line of no magnetic declination. Blaeu here buttresses his argu-ment
with the authority of the mathematician of Bruges, Simon Stevin. It
is necessary, Blaeu asserted, to select a place &xé et arresté». And since one
such place exists in one of the Canaries, it should be chosen. The choice,
(quoting Simon Stevin) he soncluded, should be Pico de Teide. He descri-bes
the mountain as rising rapidly from a large base to a very sharp point
like a sugar loaf. Thus we have, in Tenerife, he wrote, «la plus grande, la
plus riche, et la plus excellente des sept Mes de Canarie. S'il y a quelqu'un
qui trouve un autre lieu plus propre en tout l'univers, ce sera judicieuse-ment
fait de la choisir . Mais en que1 lieu que ce soit, que le choix se face, il
faut eviter I'ambiguité dont nous avons parlé»*.
The wonders of El Pico were often sung in the literature of the period.
R. Stafforde, in A Geographid and Anthologicall Description of all the
Empires and Kingdomes, both of Continent and Islands in this terrestriah'
Globe (London, 1634) wrote of «Tanariffa, wherein is a Mountaine so high,
that the inhabitants have al1 their fresh water from a Cloud that droppeth
there very fast, hanging about a treed. The story of the miraculous tree of
Tenerife was a staple item in descriptions of the Canaries for centuries.
The authors of the Thesuzlrzls Geogruphicixs: A New Boa$ ofGeog~a-phy;
07, A Compleat Description of the Earth (London, 1695), describes El
Pico asahought to be the highest mountain in the World, the top of it may
Le A:-+:..-+l.. -,...- L ,.* C-a -+ +La J:-+ ---- -f 907 E.--[:-L -:l-... --a
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3. W.G. PERRIN, eThePrirneMeridian~T, he MaíiIer'sMiror, VoI. 13 (London, 1927),
109-124, at 116-118.
4. Johan BLAEU, Le GrandAtlas ozr Cosmographie Blaviene (Amsterdam, 1663, facsimile
edition in 12 vols., Amsterdam: Theatrurn Orbis Terrarum. 1969), Chap. viii; Sirnon STEVIN,
Les Oezrvres Matbematiqzces de Simon Stevin de Bmges.. . par Albert Girard (Leyden, 1634),
p. 105.
5. R. STAFFORDE, A Geograpbicalland AnthologicaII Desception of alltbe Empires and
Kingdomes, both of Continent and Islands in ~ h i ct e n - e ~ t dGl lobe (London, 1634). pp.
36-37.
cannot go up to it, except in the months ofJdy and Auggzrst~t; for al1 the rest
of the Year it is cover'd with Snow, though Snow never falls, neither in Te-nenz
nor in any other of the Canary-Islandp>b.
The most prestigious confirmation ot the legitimacy of the Canaries as
the site of the prime meridian was the decree of Louis XIII, published on
July 1, 1634, declaring, after having convened a panel of scientists to reco-mend
the appropriate location of a prime meridian, that it should run
through the Canaries, and in particular through the «I'ile de F e r ~(H ierro or
Fero). The decree cited not only the authority of Ptolemy, but also that of
Andrés García de Céspedes, whose Regimzento de Navegación (Madrid,
1601), Chapter 52 spoke of «el Meridiano fixo que passa por las Canarias,
de donde comunrnente se cuentan las longitudines. Louis XIII directed
that French ships not attack Spanish or Portuguese ships in waters lying east
of the prime meridian and north of the Tropic of Cancer, and, in order that
aii shouid be aware of fhe geographical areas involved, he forbade «al1 pi-lots,
hydrographers, designers or engravers of rnaps or terrestrial globes to
innovate or vary from the ancient meridian passing through the most west-erly
of the Canary Islands, without regard to the novel ideas of those who
have recently fixed it in the Azores on the supposition that there the com-pass
does not vary, for it is certain that this happens also in other places that
have never been taken for the meridiam7.
It was appropriate that the prime meridian ran through the Canaries
through rnuch of the moderns world's history, as Jean-Joseph La Montre
wrote in 1702, because the Canaries form the natural division between the
old world and the new. Look at a world map, La Montre noted, and see
that it is the rnost natural and most favorable disposition for a prime meri-dian
that it is possible to choose. La Montre noted that Cardinal Richelieu
did not feel it necessary to the interests of the King or of the State to require
that a prime meridian based on astronomical observations run through Pa-ris.
Jus as Ptolemy had made his astronomical observations in Alexandria
whiie choosing the Canaries as the geographicai site of the prime meridian,
6. Thesaums Geographiczls: A New Body of Geography; 07, A Compleat Descrz$tion of
the Eartb.. . Collected witb great care Jrom the most approved Geograpbers and Modem Tra-vellers
andDiscoveries, by severaZhands (London, 1695), Chap. iii, p. 9.
7. LAGARDE, ~Historiqued u probleme du Méridien~p, . 293; Perrin, J h e P rime Meri-dian,
p. 119; Andres GARCIA DE CESPEDES, Regimiento de Navegación (Madrid, 1601),
Chap. 52.
so Richelieu felt it logical to make the distinction between astronomical and
geograhical uses of a prime meridiana.
This distinction between a umeridien d'observation» (on which obser-vatories
were established) and a umeridien de compte (universal), or meri-dian
of calculation or reckoning, marking the zero of longitude, was later
emphasized at nineteenth-century conferences on the meridian question,
for example, by Colonel Wauwermans at Antwerp in 1882 and by M.
Thury at Geneva in 1883.
On the other hand, Perrin is more cynical about Richeliu's motives,
rejecting the claim of scientific «disinterednes~m> ade for him and attribut-ing
the choice of the Canaries to the practica1 need to fix a ciear h e of de-marcation
for the hostilities going on at sea with Spain against whom open
war had been declared the preceding May. «The abstract devotion to science
of which so m ~ c hwa s made iíi 1884 (at the Wa~hiiigioíiC onfereilce)~i,r i
Perrin's words, uwas an acquired me r i ~I.t was merely another case of «no
peace beyond the lines9.
With the creation of the royal Académie des Sciences in 1666, France
began a program of research in astronomy, geodesy and cartography. Schol-ars
from other countries, like the Italian Cassini, were brought to France. A
prograni of mapping the king's realms was undertaken in 1680 by the order
of Louis XIV by two members of the Academy of Sciences, Jean Picard and
de la Hire. Their work was based on observations made at the Paris Obser-vatory
founded in 1667. Their repon of 1682 siated c<we thought we had
better not mark the longitudes as they are ordinarily shown on maps, com-mencing
from the Isle of Ferro as han been decreed, because we did not
know the position of this island in respect to the Observatory>lo.
Although the Royal Society of London for lmproving Natural Know-ledge
-the British equivalent of the French Académie des Sciences- had
been founded (in 1662) by Charles 11 four years eralier than the French Aca-
8. LAGARDE, eHistorique du probkme du Méridiem, p. 297.
9. PERRIN, «The Prime Meridiam, p. 119; The conferences at which the issue was previous-ly
discussed are recorded in SeptiZme Conféence Géodésique Intemationde tenue 2 Rome en
Octobre 1883: Rapport sur l'znifcation des l'ongitarde~pa r Wo p t i o n d'un premier ménnXeen
=nique ~t ~tit.>int.ro&ction &=no helro uz&=r~~!!(eR eme: !mp:irne:i~ P,o.;a!e. !SV:), pp. 1-
29; Bouthillier de BEAUMONT, Dissertafion sur l'adoption dím méridien initial uni-que
pré~entée au Congres Géographzque de Nancy (Nancy: Irnprmerie Berger-Levrault et
Cie, :880), pp. 1-19,
10. PERRIN, xThe PrimeMeridianx, p. 120.
démie it was not until the French interest in «finding the longitude» had
communicated itself to King Charles through his French mistress, Louise de
Kerouaile (1649-1734), that the British took the decisive steps that led to
the creation of the Gteenwich Observatory, leading to its ultimate designa-tion
as the site of the world's prime meridian. Derek Howse tells the story
in his Geenwich Time and the Discovery of the Longitzlde (New York:
Oxford University Press, 1980). Louise, created Duchess of Portsmouth
after her naturalization in 1673, did not personally champion the search
but acted as the patron of Le Sieur de St. Pierre, a Frenchman at the English
court, who claimed to have a method for the discovery of the longitude.
Through constant irnportuning of the Duchess, he obtained an opportunity
to present his plan to a distinguished group of English scientists in 1675. In
the process the King was fully informed of French efforts to survey France
and determine longitude and signed a roya1 warrant March 4. 1675, ap-pointing
John Flamsteed his «astronomical observato~c, harging him with
finding the longitude, and authorizing the creation of the Greenwich Ob-servatory.
Flamsteed demolished St. Pierre's theory in the process and
began England's march to scientific preeminence in navigationl1.
Meanwhile the French were making efforts to measure the difference
in longitude between the Paris Observatory and Ferro. The uncertainty
seemed to be resolved by the geographer Guillaume Delisle (1675- 1726) in
1700 in an article in the Joumal des scavans and, again, in 1722, in a
memoire entitled Détermization géographique de h sit~atione t de l'éten-due
des dzfferentspa&es de la Terre. In this latter work, Delisle justified
«ce chiffre rond de 20°» as the longitude of Ferro even though others had
found it a few minutes o e 2 .
Delisle's figure was generally adopted despite the fact that a 1724 geo-desic
mission sent to the Island of Ferro under the leadership of Father
Louis Fauillée, of Marseilles, obtained the result of 19O55'3" west of Pa-risl3.
A!th~ugh corresed by a !ate: expedkim, i: 1789, which placed :he
Island of Ferro definitively at 20'31' from Paris, causing Delisle's prime
meridian to fa11 between the islands of Gomera and Palma, Delisle's
convenient calculation tended to remain in use.
11. HOWSE, Greenwich Time, pp. 19-30.
12. LAGARDE, dHistorique du probleme du Méridiem, pp. 296-298.
13. Ibid., p. 298; Alfredo HERRERA PIQUE, *Estancia en las Islas Canarias de Louis Feuil-lée,,
in Francisco Morales Padrón, ed., IV Coloquio de Historza Canario-Amerzcana (1980), 2.
Vols., (Gran Canaria, 1982), 11, 741-761.
But, as more and more national observatories opened, new prime me-ridians,
based on different world capitals, come into use. Delisle's prime
meridian in Ferro came under question. As M. Janssen, the French delegate
to the Washington Conference for Fixing a Prime Meridian and a Universal
Day, held in October 1884, noted, the 20° line of Delile«ceased to be neu-tral
and became merely the meridian of Paris disguised, as has been truly
said, and the English, notably, never adopted it».14. On English charts of
the early eighteenth century the zero meridian is usually the Lizard, or
London, or sometimes Ferro. By the middle of the eighteenth century,
Greenwich begins to be substituted on English charts. With the publication
of the tables in the British Nautical Almanac in 1767 based on the Green-wich
Observatory more and more nations, including the United States,
began to utilize Greenwich as the prime meridian15.
TIiLi-c c-v--il kis.i ~ria iid üiicertaiíity cmsed b y m i m m ~ s=d c ~ f i f i i c tSi ~ n
prime meridians on the charts of the world led, in the nineteenth century,
to an attempt to obtain international agreement upon a «neutral> prime
meridian, one not idemified with any particular country. The proposal of
H. Bouthillier de Beaumont, Président of La Société de Geographie de Ge-
&ve, in his Choix d'un Méridien Initzal Unique (Geneva, l88O), for a pri-me
meridian splitting the North American and Asian continents in the Ber-ing
Straits and running through the largely open Pacific Basin, found in-creasing
favor with those, particularly French, who perceived and over-whelming
predilection on the part of others to seIect Greenwich from
among the national meridians, should such a choice eventually be made
among existing national meridians.
Professor Piazzi Smyth, Astronomer Roya1 for Scotland, on the other
hand, advocated a prime meridian based on the Great Pyramid at Gizeh.
Professor Smyth, in his contribution to the Report of Committee on Stand-ard
Time and Prime Meridian, International Institute for Preserving and
D 3 - - c : - - \VI-:.--Lo - -A ' h K - ~ ~ ~ ~ - - .--7 ,hl' 1, d +L.- + ; + l e TY7Lnt C X n l l ho 1 ~ 1 1 ~ ~ W~ C1l g1I l1L 3~ c% IlUL V I L d J U I C J 1 ~ U V I & I ~ UU IIdLI L 1 1 L L I L I L , V I I JWY U I JWY Y V G
the Prime Meridan for the WorZd? (Cleveland, Ohio, June 1884), noted
that «The meridian of the Great Pyramid passes over solid, habitable, and
14. Forty-eighrh Congres, 2d Session, House of Represenrarives. Ex. Doc. No. 14, Inter-national
Conference held at Washington for the Pwpose of Fiiing a Prime Meridian anda
Unive~salDay, October 1884. Protocols ofthe Proceedings (Washington, 1884), pp. 1-1 17, at
p. 34.
15. HOWSE, Greenwich Time, pp. 129-131.
this became the Instituto de Astrofísica de Canarias. The Canaries have be-come
the site of increasing interest on the part of astronomers18.
There were many of Adamic descent who did not agree that a prime
rneridian should be near Jerusalem or through Tenerife. Professor Janssen,
Director of the Physical Observatory of Paris, speaking at the 1884 Wash-ington
Conference «con calorosa eloquencim, as one of the Spanish dele-gates,
Juan Pastorin y Vacher, put it, urged that al1 attempts to settle the
issue upon an exclusively geographical basis (to say nothing of a national
basis) be set aside, and that the matter be decided on astronomical, scienti-fic,
and neutral grounds. Janssen decried the necessity for «any material
mark on the globo although he conceded that «if one be desired, though it
is in no manner necessarp, it could be established in conformity to a neu-tral
rneridian fixed in its relationship to other points by the rneasurements
of the various nationai observatoriesis.
Janssen failed to divert the growing consensus the select Greenwich as
the world's prime meridian. The Washington Conference, with France and
Brazil abstaining, voted to declare Greenwich the site of the prime meri-dian.
At the sane time, it also determined that longitude should be count-ed
in two directions up to 180 degrees, east longitude being plus and west
longitude rninus, a decision which reversed the recornmendation of the
Rome conference to count longitude in one direction frorn west to east. The
Conference also proposed the adoption of a universal day «for al1 purposes
for which it rnay be found convenient, and which shdl not interfere with
the use of local or other standard time where desirable». The universal day
was defined as «a rnean solar day> and «to begin for al1 the world at the mo-ment
of mean midnight of the initial meridian, coinciding with the be-ginning
of the civil day and date of that meridian, and is to be counted
from zero up to twenty-four hours90.
i8. Ibis:
19. Juan PASTORIN Y VACHER, MemoM sobre el Congreso Internacional de Washing-ton
(Madrid, Imprenta de Forta.net, 1885), p. 28 IntemationaC Conference heldat Washington,
p. 30.
20. HOWSE, Greenwich Time, pp. 38-151.