148 
NATURE 
[| Fune 18, 1885 
eee 
just under it. On the second dip the tail went into its pursuer’s 
mouth, and there was an end of the flyer. It always struck me 
that it seemed a strain on the fish to keep the wings extended. 
May 15 ALFRED CARPENTER 
THE UNIVERSAL MERIDIAN}? 
AQ EEER some preliminary historical matter Dr. Janssen 
proceeded :—The question as to which of all the 
meridians encircling the earth ought to serve as the 
starting line in the general numeration of the longitudes, 
is the question known as that of the frvme mertdian—a 
famous question oftentimes taken in hand, never defini- 
tively settled, and which the Congress of Washington was 
charged to decide. Such was at least its intention. 
The ancients, who had just ideas in all matters, per- 
fectly understood that a prime meridian ought to be placed 
at the origin of the lands to be measured. Marinus of 
Tyre, and after him Ptolemy, chose quite naturally, as 
the point of departure for their longitudes, the extremity 
of the world which was best known to them. What was 
this extremity? It was the islands which navigators en- 
countered beyond the pillars of Hercules in an enchanting 
climate, where the inhabitants, freed from every toil, lived 
in peace and happiness on the abundant spontaneous 
fruits of a prodigal soil, the Fortunate Isles, as they were 
called, which people pleased themselves with assigning, 
as a final resting place (Elysian fields) to the souls of 
heroes ! 
Homer, Hesiod, Pindar, Plutarch, speak to us of these 
Fortunate Isles, which were then regarded as the extreme 
limit of the western dependencies of Africa. Afterwards 
they were the unknown solitudes of the ocean. 
It is from these isles, then, that the great heir of the 
geography of the Greeks starts his numeration of longi- 
tudes. Here again, however, the ignorance of the ancients 
in the matter of measures did not allow the maintaining 
of so natural a point of departure. The indifferent know- 
ledge of the position of the Fortunate Isles damaged the 
whole system, and people later on were compelled to 
revert to the centinent where the measures were less 
uncertain. 
Following Greek science came the middle ages, when 
the scientific idea disappeared, and was replaced by a 
religious or political idea. The first line of longitudes 
was taken anywhere. People took their meridians from 
capitals, or remarkable places ; every one chose his own 
centre, and the confusion grew to be intolerable. It is 
noteworthy how it was France which gave the signal for 
the resuscitation of the scientific idea in this question, 
and that it is to the great Richelieu we owe it. 
It is, however, a false idea of Richelieu’s action to 
consider it as directed by a pure intention of scientific re- 
form, and by the desire alone of serving the general 
interests. Richelieu is above all a political spirit, and 
political interests dominate his preoccupations. At the 
same time, however, he is a unifying and innovating 
genius, who feels the necessity of order and serves that 
necessity by general, great, and elevated measures, for 
such is the form of his spirit. 
What, in fact, was the point of departure of a reform 
such as science disengaged from all personal interest 
would alone dictate at the present day? A jealous quarrel 
among maritime nations in reference to commerce ! 
At the commencement of the seventeenth century 
France made a trial of commerce in distant parts, 
particularly in the Indies and America. 
The navigation and traffic of these countries were then 
in the hands of the Spanish and Portuguese, who, 
however little they agreed on the division of these 
rich spoils among each other, were nevertheless wonder- 
fully united when there was a question of interdicting 
t Lecture by Dr. Janssen at \h2 Paris Ceographical Society. 
others from sharing in them. The French ships appearing 
in the seas either of the East or West Indies were, in 
point of fact, chased by the Spaniards and the Portuguese ! 
Awaiting the time till he had rendered the French navy 
strong enough to dispute with these nations a property 
which on the whole was the right of all the world, Riche- 
lieu sought to draw around France a maritime zone of 
protection. He accordingly negotiated and obtained that 
on this side of the prime meridian fixed on this occasion 
and to the north of the tropic of Cancer every French 
ship, whencesoever it may have come and whatever its 
cargo, should be safe from the pursuit of foreign vessels. 
Beyond these limits the argument of the strongest was to 
have force. France was at peace with Spain and Portugal 
on this side, at war on the other. A curious state of 
affairs, recalling to some extent the word of Pascal: 
“ Vérité en deca, erreur au deli!” 
And yet have we really the right at this day to look 
on an arrangement of this kind as such a strange one? 
Have we not now what the casuists of international law 
call the état de représailles—a state in virtue of which 
one may blockade the ports of a nation, burn its arsenals 
and destroy its armies, without being in declared war, 
and without ceasing diplomatic relations with it ? 
The object of the great Minister was evidently to secure 
a refuge for our marine till such time as it was able to 
contend with others—a goal for which he laboured with 
such admirable success that before his death our navy 
was constituted and the basis laid of that colonial greatness 
which came with Louis XIV. and Colbert. 
Such, then, was the political motive at work. But in 
pursuing this question of colonial commerce the mind of 
Richelieu was for a moment turned to geography. He 
needed a pure line of demarcation, not liable to be dis- 
puted, and found it in the ancient meridian of the 
Canaries. He resumes the geographical idea of Marinus 
of Tyre and of Ptolemy. He places his meridian as far 
to the west as possible in the archipelago of the Canaries— 
in the island of Ferro, and the longitudes are to be 
counted east of it. All the other meridians of the continent 
are excluded. 
Accordingly, and I insist on the fact, all the qualifica- 
tions of a universal meridian, such as science might be 
able to establish at this day, were combined in Richelieu’s 
meridian. 
(1). It is universal and fit to be so, seeing it personifies 
no nation, but is, on the contrary, the determination of a 
purely geographical idea ; namely, the position farthest to 
the west of the ancient world. 
(2). The numeration of the longitudes is very natural. 
It brings the numerical augmentation of the longitude into 
harmony with that of the local time. It sets forth no 
negative longitude—a system which, in our opinion, is 
defective, when there is a question of universal numeration 
of longitudes. 
(3). It places the first meridian in the sea, as geographers 
have always desired. 2 8) 
The appointment of Richelieu had but one fault : it was 
in advance of its time—not in respect of its utility and 
urgency, but of its means of realisation. i hae 
In order to establish a meridian at any point it is 
necessary to be able to connect this point exactly with 
all well-known points which are to be brought into rela: 
tion to it. Now, by reason of various circumstances, chiet 
amongst which was the state of war then prevailing, the 
longitude of this island of Ferro was not known till a century 
later, when P. Fouillée, astronomer and naturalist, pro- 
ceeded to the Canaries by order of the King and the 
Academy, and there made observations on the occulta- 
tions of the satellites of Jupiter, whence he determined 
the position of Orotara in Teneriffe, and consequently, 
by means of a triangulation, the position also of the island 
of Ferro. 
