sition of that part of the gulf of Panama which corresponds to the meridian of the point of San Blas, and the fort of Saint Raphael de Madinga. By glancing at the configuration of the northern and southern coasts, we easily perceive that, although the mean direction is nearly from east to west, the breadth of the isthmus does not depend on the latitudes alone. What is the height of the mountains at the point where the Isthmus is narrowest? What is the breadth of the Isthmus at the point where the chain of mountains is least elevated 2 These are the two great questions which an enlightened government should endeavour to resolve, by employing an experienced observer, whom it would be sufficient to furnish with a sextant, two time-keepers, and a barometer. No measure of elevation, and no level has ever yet been executed in the Isthmus of Panama; and neither the archives of Simancas, nor those of the council of the Indies, contain any paper of importance calculated to throw the least light on the possibility of cutting canals between the two seas. It is unfair, therefore, to accuse the ministry of Madrid of a wish to conceal matters of which they have never had any more knowledge than the geographers of London and Paris.

In the small map of Choco" which exhibits the canal dug by the priest of Novita, in a district called Bocachica, I have marked as uncertain, the direction of the coast which extends from the point of San Francisco Solano to the gulf of San Miguel. It is desirable that we should know more accurately the position of Cupica where the Spanish pilot, M. Gogueneche, made his settlement. In the map of false positions we have distinguished the result drawn by M. Cassini from the observations of longitude contained in the voyage of the Abbe Chappe, which are to be found in the Connoissance des Temps for 1784,. from the result adopted by the members of the academy of sciences who were entrusted with publishing the map of Alzate in 1772. We read on this map the following note: “The voyage of M. Chappe to California “ was the means of correcting the position of “ different places, which it may be interesting “ to specify here : - w

silver used by goldsmiths in France, is to that of all Europe, in the proportion of one to four, and we find that the value of the total fabrication of Europe must amount to 120 millions of francs per annum. I shall not discuss what part of these metals is derived from the melting of old plate; but I believe we may conclude from the data we have laid down, that the quantity of gold and silver extracted from the mines of Europe and Siberia (vol. iii. p. 451.) is very far from replacing the mass of the precious metals annually employed in Europe in plate, lace and gilding, or dissipated by an extreme division, or actually lost.

On the Data which served for Foundation to the Geographical Maps and Physical Sections of this Work.

In the Map of Mexico and the conterminous frontiers", the following points are founded on artronomical observations made by me in the navigation from Cumana to the Havannah, in crossing the Bank of La Vibora, and in the passage from Batabano to Carthagena.

These positions were discussed in the Recueil d’Observations Astronomiques, which were jointly published by M. Oltmanns and myself, vol. ii. p. 7, 11, 18, 56, 66, 68, 109, 112. Cape Morant, which, according to M. de Puységur, is in 17° 57° 45" of latitude, and 78° 35' 23” of longitude, was placed by M. Poirson 5' farther to the east. The more easterly position is justified by several Spanish maps.

As to the position of the town of Washington, we have not thought proper to adopt the longitude assigned to it by the Connoissance des Temps for the year 1812, which is 78° 57' 30" or half a degree too far to the east. Were this position accurate, the geographers of the United States would be at a loss where to place Baltimore and Cape Hatteras. The occultation of Aldebaran, of the 21st January 1793, observed at Washington, was calculated by Lalande, who deduced from it, no doubt, the longitude of 5h 15' 51"; but the calculation was made a second time by M. Wurm", who found 5h 17' 16", or 79° 19' 0". This last result agrees very well with the observation of an eclipse of the sun made by M. Ellicot, in 1791, at George Town, near Washington, to the west, which gives 5h 17' 40" or 79° 25' 0",

* Zach, Mon. Corresp. 1803, Nov. p. 382.