Numerous bands of Mameluke horsemen, the most formidable body of cavalry in the world, were continually hovering about the army, watching for points of exposure, and it was necessary to be continually prepared for an attack. Nothing could have been more effective than the disposition which Napoleon made of his troops to meet this novel mode of warfare. He formed his army into five squares. The sides of each square were composed of ranks six men deep. The artillery were placed at the angles. Within the square were grenadier companies in platoons to support the points of attack. The generals, the scientific corps, and the baggage were in the centre. These squares were moving masses. When on the march all faced in one direction, the two sides marching in flank. When charged they immediately halted and fronted on every side; the outermost rank kneeling that those behind might shoot over their heads--the whole body thus presenting a living fortress of bristling bayonets. When they were to carry a position the three front ranks were to detach themselves from the square and to form a column of attack. The other three ranks were to remain in the rear, still forming the square, ready to rally the column. These flaming citadels of fire set at defiance all the power of the Arab horsemen. The attacks of the enemy soon became a subject of merriment to the soldiers. The scientific men, or _savans_, as they were called, had been supplied with asses to transport their persons and philosophical apparatus. As soon as a body of Mamelukes was seen in the distance, the order was given, with military precision, "_form square, savans and asses in the centre_." This order was echoed, from rank to rank, with peals of laughter. The soldiers amused themselves with calling the asses _demi-savans_. Though the soldiers thus enjoyed their jokes, they cherished the highest respect for many of these savans, who in scenes of battle had manifested the utmost intrepidity. After a march of seven days, during which time they had many bloody skirmishes with the enemy, the army approached Cairo.