The Geographical Journal (Journal of the Royal Geographical Society): Volume XVI, No. 6 [‎350r] (52/232)

THE VOYAGES OF DIOGO CAO AND BARTHOLOMEU DIAS, 1482-88. 625
most valuable series of surveys by triangulation A surveying technique in which the position of a network of points is determined by creating a series of triangles between them and measuring at least two of the internal angles and one side length. . He produced on his first jour
ney a number of extremely valuable maps, and will, I have no doubt, do the same
with regard to his latest journey. He has also made, as Dr. Bowdler Sharpe told
us, a most important collection of specimens of mammals and birds, as well as of
batrachians and other lower forms. All this, I think, places Dr. Donaldson Smith
in a very high position as an explorer of unknown countries, and I think that he
deserves the highest praise that can be bestowed on him by geographers. I now
propose a very cordial vote of thanks to Dr. Donaldson Smith, which I feel sure will
be carried unanimously.
Note on Dr. Donaldson Smith’s Map. —Heights determined by many boiling
points, as well as aneroid observations. As far as Lake Stefanie the positions were
determined by triangulations based on points fixed by me in 1895, aided by fre
quent astronomical observations with theodolite, three chronometers, and sextant.
Between Lake Rudolf and Tarangole I depended upon triangulation A surveying technique in which the position of a network of points is determined by creating a series of triangles between them and measuring at least two of the internal angles and one side length. almost entirely,
aided by occasional astronomical observations for latitude. The base for this was
plotted in the vicinity of the northern end of the lake from my previous obser
vations, from a new set of measurements, and from points laid down by Major
Austin.—A. D. S.
THE VOYAGES OF DIOGO CAO AND BARTHOLOMEU DIAS,
1482-88.*
By E. G. RAVEN STEIN.
When Prince John, on August 26, 1481, and at the age of twenty-six,
ascended the throne of his father Affonso, he found the royal treasury
empty, and his ambitious nobles, jealous of their feudal privileges, ever
ready to defy the authority of their king. But John was strong and
energetic where his father had been weak and vacillating, cautious
where he had been rash and regardless of consequences, ^ise measures
of administration once more filled the royal coffers, and a strong hand
crushed the nascent conspiracy of the nobles.
The Guinea coast by this time had been explored as far as Cape S.
Catharina. Lopo Gonsalves had been the first to cross the line ; Fernao
Po is credited with having discovered the Ilha Formosa, which now
bears his name, in 1472 ; whilst Ruy de Sequeira, “ about the same
time,” according to Galvao,t followed the coast as far as Cabo de S.
Catharina (November 25), and also discovered the islands of S. Thome
(December 21) and S. Antonio (January 17)4 This last subsequently
* The substance of this paper was communicated at the Toronto Meeting of the
British Association in 1897. For a notice of the maps referred to, see the Appendix.
Maps, p. 712.
f Antonio Galvfio (b. 1503, d. 1557), ‘ The Discoveries of the World ’ (1555, London ;
Hakluyt Soc., 1862), p. 75.
} Faria e 8 ousa (‘Asia Portuguesa’ (Lisbon, 1675), i. p. 18; iii. p. 529) credits
Joao de Santarem with having explored the coast as far as Cabo de S. Cathariua in
1471—a most unlikely thing to have happened. Lopez de Lima (‘Ensaios sobre a