"A similar membrane terminates each foot of a common fly: beneath which a vacuum takes place, and the animal maintains a footing upon ceilings, owing to the pressure of the external air upon this membrane." Footnote 29: Clarke's Travels, vol. v. pp. 78, 80. Footnote 30: When their rations happened to be salt pork, they used to put a piece of it under the kettle to burn with the straw. Footnote 31: With the exception of gold, which was in the hands of a few, the coin circulating in Egypt was made of base metal, watered over with silver; and was of little or no intrinsic value. There were large pieces of this kind, some of them larger than a crown, which were of different values: but a small coin, called a para, about the breadth of a farthing, and no thicker than the scale of a fish, was the most common; of which 120, and in some places 160, were given for a Spanish dollar. The money expended by the army was gold and Spanish dollars. Footnote 32: The inundation in this lake extended farther than the eye could reach. The banks of the canal formed a road for communicating with the interior of the country; a bridge of boats united the banks, one of the boats being moveable, for the purpose of allowing vessels to pass in and out of Lake Mareotis. Before the army wholly left the country, the boats forming the bridge were sunk in the cut, and served for a foundation upon which the banks were rebuilt. When the British took Alexandria, in March, 1807, a detachment was sent to take Rosetta; but they were repulsed by those Turks who had accompanied the army on its march to and from Cairo, and who had acquired a considerable portion of British discipline. The rays of the sun had by this time so far dried up the salt water in Lake Mareotis as to render it passable; but the British again cut the banks of the canal, and admitted the sea into it, to protect Alexandria from being attacked by the Turks. CHAPTER VII.