The Mapping of the Earth. 565 
pointed out the various ways the present War will affect the map- 
maker, owing to the surveying and arranging of new boundaries, etc , 
as after all is over our present maps and atlases will have to be very 
largely revised and brought up to date. 
He divided his Address into the following headings : — 
1. A brief general summary of what has been done in the past 
towards the mapping of the earth’s surface. 
2. A sketch of how things stand at the present time. 
3. A few remarks upon future work, specially as regards 
instruments and methods. 
Commencing with a historical sketch of geographical exploration 
and representation of the surface features of the earth from as early 
a date as B.c. 276, the President stated that— 
It was not until the latter part of the fifteenth century, the time 
of the great Portuguese and Spanish discoveries, that any real advance 
was made, but then Europe seemed to awake from a long sleep, and 
a grand new start was made. 
One of the first acts of King John II of Portugal (1481-95), whose 
memory deserves to be equally held in respect with that of his great 
uncle Prince Henry, was the calling together of the Committee, or 
‘Junta’, of learned men to consider the best means of finding the 
latitude when the Pole Star was too low to be of service, to decide 
upon the most approved form of instrument for the taking of observa- 
tions, and to furnish suitable tables of declination, etc., for the 
computations. Equipped with the new tables, which may, perhaps, 
be considered the first Nautical Almanac, and the simplified astrolabe, 
the Portuguese navigators started on the famous voyages, with 
a much better chance of properly fixing positions than their 
predecessors. The Vernier had not: yet been invented, and so the 
difficulty of obtaining accurate readings of the circles was still 
considerable. To overcome this difficulty it was decided to construct 
astrolabes with very large®circles, and the instrument carried by 
Vasco da Gama in his famous voyage round the Cape in 1497 had 
a circle which measured just over two feet, in diameter. . . 
The difficulty of taking anything like accurate observations at sea 
was for centuries a very serious one, and long before the invention of 
the reflecting quadrant or sextant many were the attempts to devise 
some instrument for accomplishing this... . 
It was not until the ingenious invention of the reflecting octant, 
suggested first of all by Sir Isaac Newton, that anything approaching 
accuracy was possible. Hadley’s quadrant was the first of such 
instruments to be put into actual use, but there is no doubt that the 
idea should be ascribed to the famous Sir Isaac Newton, although the 
instrument was probably independently invented by Hadley. 
With the invention of the sextant, or its predecessors the octant 
and quadrant, rapid progress was made in improvements in navigation 
and surveying instruments. 
The introduction of the Nonius by Peter Nunez in the middle of 
the sixteenth century, and later of the Vernier by the Frenchman 
Francis Vernier, which, owing to its simplicity, soon superseded the 
