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case of a learned man who afterwards gained practical experience at sea which enabled him to produce a useful work. Enciso undertook a conquest of part of South America, in partnership with Alonzo de Ojeda, one of the companions of Columbus. He went through many strange adventures, and his story is mixed up with the first appearance of Vasco Nuñez de Balboa and Francisco Pizarro on the stage. As an adventurer, Enciso does not appear in an amiable light, for he was an enemy of the heroic discoverer of the South Sea. But as an author his name should not be forgotten. The "Suma de Geografia" contains the art of navigation as it was then understood, tables of declination, definitions, and an account of all the countries of the known world. It was the first answer to a demand for information which arose when all Spaniards of enterprise began to crowd westward in search of adventures and of fortune. The first edition of the "Suma" appeared at Seville in 1519, the second in 1530.

But it was soon followed by two works which secured more permanent popularity. The art of navigation by Martin Cortes, which was published at Seville in 1551, and dedicated to Charles V., contains definitions, tables of minutes in a degree of longitude on each parallel of latitude, explanations of the motions of sun and moon, and of the machinery and use of clocks, construction and use of plane charts, of the compass, the astrolabe, and cross-staff. Cortes was the first to suggest a magnetic pole, different from the pole of the earth. The other work on navigation, by Pedro de Medina, appeared at Valladolid in 1545, but never attained to the same popularity as the "Arte de Navegar" of Cortes. Medina defends, while Cortes exposes, the errors of the plane chart, and the latter is more sound on the question of compass variation, concerning which Medina talks much nonsense. Later Spanish writers improved upon the works

of Cortes and Medina, and many editions were printed to meet the requirements of students.

I have referred to these Spanish works on navigation, and to the system of instruction at Seville, because it ought to be remembered that the Spaniards would never have made their great discoveries, and afterwards have surveyed and described them with such remarkable accuracy and detail, if attention had not been given to the instruction of their sailors and surveyors. They made excellent charts of the coasts of South America and Mexico, and of Magellan's Straits, and their enemy, Sir Richard Hawkins, bears testimony to the care and skill with which they navigated their ships. One reason that full justice has never been done to the Spaniards, as skilled mariners, is that their Government maintained a policy of strict secrecy. Many excellent charts and memoirs have never yet seen the light. As one out of numerous instances of unwise suppression, I may mention that, after Captain Moresby had published his discoveries at the eastern end of New Guinea in 1876, a set of accurate charts of the very same ground was discovered at Simancas, drawn by Diego de Prado y Tovar in the year 1606, from the surveys of Torres.

But I believe I have said enough to show that Spain, in the height of her power, attached the greatest importance to the thorough training and instruction of her sailors and explorers; and that her discoveries and successes could never have been achieved without this wise and necessary provision for qualifying her sons to perform those great deeds the fame of which will endure for ages to come.

When the United Provinces began to rival Spain in maritime enterprise, the Dutch mathematicians and geographers kept pace with the sailors and explorers in their improvements and discoveries. Reinerus Gemma, a native of Friesland who lived in the first half of the sixteenth

century, was the first to suggest the method of finding longitude by means of a watch showing time at the place of departure, and of apparent time at the place of observation. He also invented a new cross-staff, and constructed astronomical instruments. His pupil, Gerard Mercator, published the famous terrestrial globe and numerous maps, while Abraham Ortelius produced the "Theatrum Orbis Terrarum,' which was the base of all subsequent geographical studies. The labours of these great men, with the treatise on navigation by Coignet and the translations of Medina, formed the materials for instructing the young sailors of Holland in the sixteenth century. Among many others who received careful instruction, the career of Lucas Wagenaar is an example of the way in which theoretical training, when united with long experience, often bears valuable fruit.

Young Wagenaar was born at Enkhuizen in about 1550, and served at sea from his boyhood. But he had received a good training in mathematics and navigation, and he became one of the best pilots in Holland. His "Spieghel der Zeevaardt," engraved at Leyden in 1584, was the first marine atlas ever published, and in subsequent editions very extensive and valuable additions were made to it, including a chart of Norway by Willem Barents. The name of this great Arctic explorer suggests an example of another Dutch worthy who had been carefully trained in the art of navigation. In his northern voyages he regularly observed with the astrolabe, cross-staff, and quadrant; and Linschoten describes him as having great knowledge of the science of navigation. He was a native of Ter Schelling, off the coast of Friesland, and this little island still has a navigation school. The Dutch, in former days, like the Spaniards, attached the greatest importance to the thorough education of their sailors and explorers; and, in like manner, it was to the

care and trouble taken to instruct them that the success of their memorable voyages of discovery is due.

When our own country, during the reigns of the Tudors and Stuarts, began to enter upon that career of discovery by land, and of daring maritime adventure, which soon placed us in the foremost rank among nations, the necessity for instruction in the art of navigation was at once felt. It was at the urgent request of one of our earliest Arctic navigators, Stephen Burrough, that Master Richard Eden undertook the translation of the navigation book of Cortes. It first appeared in 1561, and was very generally used, passing rapidly through ten editions. But the work on navigation used by Sir Martin Frobisher, during his first voyage in 1576, was a Spanish edition of Medina. His other appliances were a great globe, a nautical sphere, a clock, an astrolabe, a crossstaff, compasses, hour glasses, and charts.

The first English navigation book that was in general use was the "Regiment of the Sea," published by William Bourne in 1573. It was designed merely as a supplement to Cortes, whom Bourne often quotes; but it contains many new methods and suggestions, and Bourne was the first to describe the log and line for estimating the rate of a ship. Bourne was followed by several other writers, during the reign of Elizabeth, who devoted themselves to the laudable object of supplying instruction to sailors and travellers. John Blagrave, a country gentleman who lived at Southcote Lodge, near Reading, and died there in 1611, invented a new kind of astrolabe, and wrote what he called "a necessary and pleasant solace for navigators." Robert Tanner, in 1587, published "A sure safety for Sailors; " Thomas Blundeville contributed treatises on the art of navigation, "verie necessary to be read and learned by all young gentlemen that are desirous to have a knowledge as well in cosmography and geography as in navigation." This book, which first appeared in 1594, was

very popular, and quickly went through several editions. Dr. Thomas Hood was another eminent author and teacher of navigation in those days. He published works on geometry, and on the use of the globes "most plainely delivered in form of a dialogue; containing most pleasant and profitable conclusions for the mariner."

Edward Wright, who made the voyage with the Earl of Cumberland in 1589, was, however, the mathematician whose labours were most serviceable to the navigator, for he discovered the projection for sea charts which is generally attributed to Mercator. In 1599 he published a book in which he fully explains the principle of the projection, and gives a table of meridional parts. Wright also worked, in conjunction with the geometrician, Henry Briggs, to introduce the use of logarithms. He translated Lord Napier's “Logarithmorum Descriptio," which was published by his son Samuel, while Briggs undertook a journey to Edinburgh to discuss the matter with Napier, and, in 1624, gave his work on logarithmic arithmetic to the world. Briggs's tables for the improvement of navigation were published in 1610, with the second edition of Wright's book.

Terrestrial magnetism was also studied in England, with useful practical results, during the reign of Elizabeth; and the variation of the compass has been observed since 1580. In 1581 William Borough published his "Discourse of the Magnetic Needle;" and "The New Attractive," by Robert Norman, announced in 1585 the discovery of the dip of the needle. But the great work on the magnet, in those days, was written by Dr. Gilbert, of Colchester, in 1600. This author was the first to point out the magnetic properties of the earth, and to show that the earth, by its directive force, performed, relatively to the compass needle, the office of a real magnet.

There were several other writers on navigation in the

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