The Life and Voyages of Christopher Columbus (Volume II)

the islands as laid down agree completely with the bearings and distances given in the journal of Columbus, and establishes the identity of San Salvador, or Cat Island, and Guanahani.
    “I feel happy,” says M. de Humboldt, “to be enabled to destroy the incertitudes (which rested on this subject) by a document as ancient as it is unknown; a document which confirms irrevocably the arguments which Mr. Washington Irving has given in his work against the hypotheses of the Turk’s Island.” In the present revised edition the author feels at liberty to give the merit of the very masterly paper on the route of Columbus, where it is justly due. It was furnished him at Madrid by the late commander Alexander Slidell Mackenzie, of the United States navy, whose modesty shrunk from affixing his name to an article so calculated to do him credit, and which has since challenged the high eulogiums of men of nautical science.
    No. XVIII.
    Principles upon which the Sums Mentioned in This Work Have Been Reduced into Modern Currency.
    In the reign of Ferdinand and Isabella the mark of silver, which was equal to 8 ounces or to 50 castellanos, was divided into 65 reals, and each real into 34 maravedis; so that there were 2210 maravedis in the mark of silver. Among other silver coins there was the real of 8, which consisting of 8 reals, was, within a small fraction, the eighth part of a mark of silver, or one ounce. Of the gold coins then in circulation the castellano or dobla de la vanda was worth 490 maravedis, and the ducado 383 maravedis.
    If the value of the maravedi had remained unchanged in Spain down to the present day, it would be easy to reduce a sum of the time of Ferdinand and Isabella into a correspondent sum of current money; but by the successive depreciations of the coin of Vellon, or mixed metals, issued since that period, the real and maravedi of Vellon, which had replaced the ancient currency, were reduced, towards the year 1700, to about a third of the old real and maravedi, now known as the real and maravedi of silver. As, however, the ancient piece of 8 reals was equal approximately to the ounce of silver, and the duro, or dollar of the present day, is likewise equal to an ounce, they may be considered identical. Indeed, in Spanish America, the dollar, instead of being divided into 20 reals, as in Spain, is divided into only 8 parts called reals, which evidently represent the real of the time of Ferdinand and Isabella, as the dollar does the real of 8. But the ounce of silver was anciently worth 276-1/4 maravedis; the dollar, therefore, is likewise equal to 276 1/4 maravedis. By converting then the sums mentioned in this work into maravedis, they have been afterwards reduced into dollars by dividing by 276 1/4.
    There is still, however, another calculation to be made, before we can arrive at the actual value of any sum of gold and silver mentioned in former times. It is necessary to notice the variation which has taken place in the value of the metals themselves. In Europe, previous to the discovery of the New World, an ounce of gold commanded an amount of food or labor which would cost three ounces at the present day; hence an ounce of gold was then estimated at three times its present value. At the same time an ounce of silver commanded an amount which at present costs 4 ounces of silver. It appears from this, that the value of gold and silver varied with respect to each other, as well as with respect to all other commodities. This is owing to there having been much more silver brought from the New World, with respect to the quantity previously in circulation, than there has been of gold. In the 15th century one ounce of gold was equal to about 12 of silver; and now, in the year 1827, it is exchanged against 16.
    Hence giving an idea of the relative value of the sums mentioned in this work, it has been found necessary to multiply them by three when in gold, and by four when expressed in silver. [335]
    It is expedient to add that the dollar is reckoned in this work at 100 cents of the United States of North America, and four shillings and sixpence of England.
    No. XIX.
    Prester John:
    Said to be derived from the Persian Prestegani or Perestigani , which signifies apostolique; or Preschtak-Geham , angel of the world. It is the name of a potent Christian monarch of shadowy renown, whose dominions were placed by writers of the middle ages sometimes in the remote parts of Asia and sometimes in Africa, and of whom