LONGITUDE AND TIME-RECKONING. 139 
As far as practicable, the interests of all nations should be con- 
sulted in its choice, and the principle should be recognized, that the 
first meridian should be determined in accordance with the views of 
the greatest possible number. 
Although the general acceptance of a common meridian for reckon- 
ing longitude has long been desired, unanimity has in no way been 
attained. 
The meridians passing through the following points are more or 
less in use at the present time, viz.: Cadiz, Christiania, Copenhagen, 
Ferro, Greenwich, Lisbon, Naples, Paris, Pulkova, Rio de Janeiro, 
Stockholm, and Washington. 
Several other meridians have at different times been used, or pro- 
posed to be used, for the computation of longitude. Ptolemy, to 
whom we are indebted, along with Marinus, for introducing the terms 
‘longitude’ and ‘latitude,’ drew the first meridian through the Insuleze 
Fortunate, or Canary Islands, as the western limit of the earth’s 
boundaries of his time; the exact position is not known with 
certainty. 
According to Malte Brun, Louis XIII. of France, in order to 
render the manner of expressing longitude in French geography uni- 
form, ordered, by an express declaration, that the first meridian should 
be placed in the Isle of Ferro, the most western of the Canaries. 
Delisle, one of the first who éndeavoured to give precision to geo- 
graphical determinations, fixed the longitude of Paris 20 degrees east 
of that meridian. When, by more rigorous observations, it was known 
that the difference of longitude between Paris and the principal town 
of the Isle of Ferro was 20° 5’ 50”, it was necessary to advance the 
first meridian 5’ 50” to the east of that point, so that it is now a circle 
of mere convention, which passes through no remarkable point. 
Geographers at one time established the first meridian at the 
island of St. Nicholas, near Cape Verd; others at the isle of St. 
James. Gerard Mercator, who lived in the sixteenth century, 
selected the meridian passing through the Island del Corvo, one of 
the Azores, on account, it is said, of the magnetic needle pointing 
due north at that time. It was not then known that the needle 
itself was subject to variations. The Dutch placed their first 
meridian at the Peak of Teneriffe. The Spaniards have chosen 
Cadiz. The British formerly used Cape Lizard, but subsequently 
selected Greenwich Observatory, near London. The Russians, Pul- 
