of Ptolemy Euergetes to Aduli; nor the passage of the straits, though Eratosthenes, as cited by Strabo, proves that it was open in his time.  In the time of Artemidorus, however, the trade of Egypt on the coast of Africa had reached as low down as the Southern Horn; that this trade was still in its infancy, is apparent from a circumstance mentioned by Strabo, on the authority of Artemidorus; that at the straits the cargo was transferred from ships to boats; bastard cinnamon, perhaps casia lignea or hard cinnamon, is specified as one of the principal articles which the Egyptians obtained from the coast of Africa, when they passed the straits of Babelmandeb.

The next person belonging to the Alexandrian school, to whom the sciences on which geography rest, as well as geography itself, is greatly indebted, was Hipparchus.  Scarcely any particulars are known respecting him:  even the exact period in which he flourished, is not accurately fixed; some placing him 159 years, others 149, and others again bringing him down to 129 years before Christ.  He was a native of Nice in Bithynia, but spent the greater part of his life at the court of one of the Ptolemies.  It is supposed that he quitted his native place in consequence of some ill treatment which he had received from his fellow citizens:  at least we are informed by Aurelius Victor, that the emperor Marcus Aurelius obliged the inhabitants of Nice to send yearly to Rome a certain quantity of corn, for having beaten one of their citizens, by name Hipparchus, a man of great learning and extraordinary accomplishments.  They continued to pay this tribute to the time of Constantine, by whom it was remitted.  As history does not inform us of any other person of note of this name, a native of Nice in Bithynia, it is highly probable that this was the Hipparchus, the astronomer and geographer.  That it was not unusual for conquerors and sovereigns to reward or punish the descendants of those who had behaved well or ill to celebrated men who had flourished long previously, must be well known to those conversant with ancient history.  The respect paid to the memory of Pindar, by the Spartans, and by Alexander the Great, when they conquered Thebes, is a striking instance of the truth of this observation.

Hipparchus possessed the true spirit of philosophy:  having resolved to devote himself to the study of astronomy, his first general [principal->principle] was to take nothing for granted; but setting aside all that had been taught by former astronomers, to begin anew, and examine and judge for himself:  he determined not to admit any results but such as were grounded either in observations and experiments entirely new, made by himself or on a new examination of former observations, conducted with the utmost care and caution.  In short, he may justly be regarded as one of the first philosophers of antiquity who had a slight glimpse of the grand maxim, which afterwards immortalized Bacon, and which has introduced modern philosophers to a knowledge of the most secret and most sublime operations of nature.