448 



NA TURE 



[August 31, 1905 



represents as entirely surrounded by the sea — a circumstance 

 apparently either forgotten or disbelieved in later years. 



Erotosthenes, 250 B.C., and Hipparchus, 150 B.C., made 

 great advances, and the former made the first attempt to 

 measure the size of the earth by the difference of latitudes 

 between Assouan and Ale.\andria in Egypt, an attempt 

 which, considering the great imperfection of his means, 

 was remarkably successful, as, assuming that we are right 

 in the length of the stadium he used, he made the circum- 

 ference of the globe 25,000 geographical miles, whereas 

 it should be 21,600. 



He a'so devised the system of meridians and parallels as 

 we now have them ; but the terms " latitude " and " longi- 

 tude," to denote positions on those circles, were introduced 

 by Ptolemy. 



The maps of Ptolemy, the great Alexandrian astronomer 

 and geographer of a.d. 150, are the earliest we possess. 

 He drew, besides a general map of the whole known 

 world from the southern part of the Baltic to the Gulf of 

 Guinea, north and south, and from the Canary Islands 

 to the China Sea, east and west, a series of twenty-six 

 maps of the different parts. 



Ptolemy's maps and his method of representing the 

 spherical globe on a flat surface had a great influence on 

 Geography for many years. After his time the Greek 

 civilisation waned, and the general decline of the Roman 

 Empire, followed by its disruption by the invasion of 

 barbarians, closed the course of discovery in all branches 

 of research for centuries. It is not too much to sav that 

 for 1300 years no advance was made, and until the com- 

 mencement of exploration by sea, which accompanied the 

 general revival of learning in the fifteenth century, 

 Ptolemy's maps represented the knowledge of the world. 



As might be expected, the further he got from the Medi- 

 terranean, the greater were his errors ; and his representa- 

 tions of Eastern Asia and North-Western Europe are some- 

 what grotesque, though quite recognisable in the main. 



Of Africa south of the Equator he knows nothing, and 

 his map of it terminates with the border. 



This is somewhat remarkable, as I am one of those who 

 firmly believe in the circumnavigation of Africa by the 

 Phoenicians sent by Necho, King of Egypt, in 600 B.C. from 

 the head of the Red Sea. As described bv Herodotus, the 

 voyage has all the impress of veracity. My personal faith 

 in Herodotus was much strengthened by finding when I 

 surveyed the Dardanelles in 1872 that his dimensions of 

 that strait were nearer the truth than those of other and 

 later authorities, even down to the time at which I was 

 at work, as well as by other geographical tests I was 

 able to apply. When, therefore, he records that the 

 Phoenicians declared that in their voyage they had the sun 

 on their right hand, and says he does not believe it, he 

 registers an item of information which goes far to prove 

 the story correct. Influenced by Hecata^us, who though 

 surrounding Africa by the sea cut it far short of the 

 Equator, Herodotus could not conceive that the travellers 

 had passed to the south of the sun when it was in the 

 southern tropic. 



No historical incident has been more discussed than this 

 voyage, commentators varying much in their opinions of 

 its truth. But we have to-day some new facts. No one 

 who has followed the exploration of the ancient buildings 

 in Rhodesia, and considered the information we possess on 

 the early inhabitants of Southern Arabia, whether we call 

 them Sabaeans or Himyarites, can doubt that the former 

 were mainly the work of men coming from Arabia at a 

 very early date, while the period of time necessary to carry 

 out gold-mining operations over the large areas now found 

 to have been exploited must have been very great. 



It seems strange that no record of the constant voyages 

 to this El Dorado should remain, but the very natural desire 

 to keep lucrative information to themselves is not an un- 

 known thing amongst traders of the present day, while the 

 conditions of society and the absence of written records of 

 .South Arabia would make concealment easy. 



The Phcenicians, an allied race, and the great seafaring 

 trading nation of the Mediterranean, succeeded in keeping 

 the majority of their marts secret, and we have incidents 

 recorded showing their determination not to allow others 

 to follow their steps, while to this day we are very doubtful 

 of the limits of their voyages. 



NO 1870, VOL. 72] 



It may be considered certain that while we naturally 

 quote Greek historians and geographers as the early au- 

 thorities for the growth of geographical knowledge, and 

 that the scientific basis for proper maps of large areas 

 was really provided by them, the seafaring nations, 

 .Arabians, Phoenicians, and Chinese, knew a very great 

 deal practically of the coasts of various parts of the Old 

 World that were absolutely unknown to the Greeks. 



The favourable conditions afforded by those remarkable 

 periodic winds, the monsoons, would in the China Sea, Bay 

 of Bengal, and the Arabian Sea naturally facilitate any 

 attempts at extensive sea voyages, and would lead to such 

 attempts under conditions that in the regions of variable 

 winds would be considered too dangerous and uncertain. 

 The fact that the monsoons in nearly every case blow prac- 

 tically parallel to the coasts in opposite directions is a most 

 important factor in considering early navigation. The 

 direction of the wind itself in such cases roughly guides a 

 vessel without a compass, and the periods of cyclones and 

 unsettled weather between the monsoons would soon be 

 noted and avoided, as they are to this day by the 

 Arabs and Chinese, whose vessels, I have very little 

 doubt, have remained practically the same for thousands 

 of years. 



The unknown Greek author of that unique and most 

 interesting document, the " Periplus of the Erythrfean 

 Sea," probably of the first century a.d., describes vessels 

 built without nails, the planks of which were bound together 

 by cords, in precisely the same way as many Arab dhows now 

 navigating the Indian Ocean. His personal knowledge of 

 .'\frica evidently ceased at Cape Guardafui, though he gives 

 information gained from others on the East Coast as far 

 as Zanzibar, which — or, rather, a part on the mainland near 

 — he describes as the limit of trade to the south. We know 

 that Arabs had penetrated further, but no doubt they kept 

 their knowledge to themselves. 



These early navigators very probably had charts. When 

 Vasco da Gama first passed along the eastern coast of 

 Africa he found that the Arab dhows had charts. Un- 

 fortunately none of them has come down to us, or it would 

 have been interesting to compare them with those of the 

 West Coast used by the Portuguese at the time, and 

 which were of the crudest description. 



I claim for sailors of all ages that they would be the 

 first to make practical maps of the shape of the coasts. 

 Their safety and convenience demanded it, while it is a 

 far easier task to compile such a picture of the earth from 

 successive voyages along coasts over the sea, where average 

 distances from known rates of sailing and courses from the 

 sun and stars can be more accurately ascertained, than 

 from long and generally tortuous land journeys in directions 

 governed by natural features, towns, and so forth. \ 

 navigator must be a bit of an astronomer. A landsman 

 to this day seldom knows one star from another. 



It was the sea-charts, or portolani, of the Middle Ages 

 that on the revival of learning first gave respectable re- 

 presentations of the shape of the coasts, at a time when 

 the learned monks and others were drawing the most 

 fantastic and absurd pictures which they called maps. 



At the same time it must be remembered that in all 

 ages and down to the present day pilots, who within a 

 hundred years were usually carried by all ships, even for 

 sea voyages, jealously keep their knowledge largely in 

 their heads, and look upon good charts as contrivances to 

 destroy their profession, and that such charts or notes 

 as they had they would keep religiously to their fraternity. 



The Egyptians were no sailors, but we know that they 

 habitually employed Phoenicians for sea expeditions, while 

 we have the historical record of the Old Testament for 

 their employment by David and Solomon for a like purpose 

 in the Red Sea, and probably far to the south. It is, 

 therefore, almost impossible to doubt that the Phoenicians 

 were also acquainted with the navigation of the Red Sea 

 and east coast of Africa. Such a voyage as that recorded 

 by Herodotus would in these circumstances be far from 

 improbable. 



The varying monsoons which had led the Arabians cen- 

 turies before to get so intimate a knowledge of the east 

 coast as to enable them to find and work the goldfields 

 would be well known to the Phoenicians, and the hardy 

 seamen who braved the tempestuous regions lying between 



