G28 COSMOS. 



the middle ages, have been transmitted to Venice through 

 Egypt, Abyssinia, and Arabia. The triangular form of 

 Africa is indeed distinctly delineated as early as 1306, on 

 the planispherium of Sanuto, in the Genoese Portulano detta 

 Mediceo-Laurenziana of 1351, discovered by Count Baldelli; 

 and on the map of the world by Fra Mauro. I have briefly 

 alluded to these facts, since the history of the contemplation 

 of the universe should indicate the epochs at which tne prin- 

 cipal details of the configuration of great continental masses 

 were first recognised. 



Whilst the gradually developed knowledge of relations in 

 space incited men to think of shorter sea routes, the means 

 for perfecting practical navigation were likewise gradually 

 increased by the application of mathematics and astronomy, 

 the invention of new instruments of measurement, and by a 

 more skilful employment of magnetic forces. It is extremely 

 probable that Europe owes the knowledge of the northern and 

 southern directing powers of the magnetic needle, the use 

 of the mariner's compass, to the Arabs, and that these people 

 were, in turn, indebted for it to the Chinese. In a Chinese 

 work (the historical Szuki of Szumathsian, a writer who lived 

 in the earlier half of the second century before our era) we 

 meet with an allusion to the "magnetic cars," which the 

 Emperor Tschingwang, of the ancient dynasty of the Tscheu, 

 had given more than nine hundred years earlier to the ambas- 

 sadors from Tunkin and Cochin China, that they might not 

 miss their way on their return home. In the third century 

 of our era, under the dynasty of Han, there is a description 

 given in Hiutschin's dictionary Schuewen, of the manner in 

 which the property of pointing with one end towards the south, 

 may be imparted to an iron rod by a series of methodical blows. 

 Owing to the ordinary southern direction of navigation at that 

 period, the south-pointing of the magnet is always the ono 

 especially mentioned. A century later, under the dynasty of 

 T sin, Chinese ships employed the magnet to guide their course 

 safely across the open sea ; and it was by means of these ves- 

 sels that the knowledge of the compass was carried to India, 

 and from thence to the eastern coasts of Africa. The Arabic 

 designations Zohron and Aphron (south and north),* which 



* Avron, or avr (aur), is a more rarely employed term for north, 

 used instead, of the ordinary " schemdl;" the Arabic Zohron, or Zolir, 



