The grain of the merchants was shipped from Alexandria to the chief ports of Europe, between Constantinople in the east and Cornwall in the west. Britain had been left by the Romans, as too remote for them to hold in their weakened condition; and the native Britons were then struggling against their Saxon invaders, as in a distant corner of the world, beyond the knowledge of the historian. But to that remote country the Alexandrian merchants sailed every year with grain to purchase tin, enlightening the natives, while they only meant to enrich themselves. Under the most favourable circumstances they sometimes performed the voyage in twenty days. The wheat was sold in Cornwall at the price of a bushel for a piece of silver, perhaps worth about twenty cents, or for the same weight of tin, as the tin and the silver were nearly of equal worth. This was the longest of the ancient voyages, being longer than that from the Red Sea to the island of Ceylon in the Indian Ocean; and it had been regularly performed for at least eight centuries without ever teaching the British to venture so far from their native shores. The suffering and riotous citizens made Alexandria a very unpleasant place of abode for the prefect and magistrates. They therefore built palaces and baths for their own use, at the public cost, at Taposiris, about a day's journey to the west of the city, at a spot yet marked by the remains of thirty-six marble columns, and a lofty tower, once perhaps a lighthouse. At the same time it became necessary to fortify the public granaries against the rebellious mob. The grain was brought from the Nile by barges on a canal to the village of Chaereum, and thence to a part of Alexandria named Phialae, or _The Basins_, where the public granaries stood. In all riots and rebellions this place had been a natural point of attack; and often had the starving mob broken open these buildings, and seized the grain that was on its way to Constantinople. But Justinian surrounded them with a strong wall against such attacks for the future, and at the same time he rebuilt the aqueduct that had been destroyed in one of the sieges of the city. In civil suits at law an appeal had always been allowed from the prefect of the province to the emperor, or rather to the prefect of the East at Constantinople; but as this was of course expensive, it was found necessary to forbid it when the sum of money in dispute was small. Justinian forbade all Egyptian appeals for sums less than ten pounds weight of gold, or about two thousand five hundred dollars; for smaller sums the judgment of the prefect was to be final, lest the expense should swallow up the amount in dispute.