"Yes, we have a good many. And they form a most important part of our defence, for we are not very well supplied with men, and the Egyptian troops are not to be depended on unless backed up by ours. These mines require to be carefully handled, however, for our shepherds take the cattle out to graze every day, so that if I were to fail to disconnect any of them in the mornings, we should have some of our cattle blown up; and if I failed to connect them again at night, the enemy would attack us more vigorously. As it is, they are very nervous about the mines. They have pluck to face any foe that they can see, but the idea of an unseen foe, who lurks underground anywhere, and may suddenly send them into the sky like rockets, daunts them a bit." "And little wonder!" returned the captain. "From what you say I judge that you have the management of most of the mines." "Of all of them," answered the lieutenant, with a modest look. There was more than modesty in this young officer of Engineers; there was heroism also. He might have added, (though he did not), that this duty of connecting and disconnecting the mines each night and morning was such a dangerous service that he declined to take men out with him, and invariably did the work personally and alone. The mystery of the explosion on the night we write of was explained next morning when a party sallied forth to see what damage had been done. They found, instead of dismembered men, the remnants of a poor little hare which had strayed across the fatal line of danger and been blown to atoms. Thus do the lives of the innocent too often fall a sacrifice to the misdeeds of the guilty! Next night, however, the defenders were roused by a real attack. The day had been one of the most trying that the new arrivals had yet experienced. The seasoned men, who had been formed by Nature, apparently, of indestructible material, said it was awful. The thermometer stood at above 110 degrees in the shade; there was not a breath of air moving; the men were panting, almost choking. Even the negroes groaned, and, drawing brackish water from a well in the fort, poured it over their heads and bodies--but with little benefit, for the water itself was between 95 and 100 degrees! "It'll try some o' the new-comers to-night, if I'm not mistaken," remarked one of the indestructible men above referred to, as he rose from dinner and proceeded to fill his pipe. "Why d'you think so?" asked Sergeant Hardy, whose name was appropriate, for he continued for a long time to be one of the indestructibles. "'Cause it's always like this when we're goin' to have a horrible night." "Do the nights vary much?" asked Armstrong, who was still busy with his knife and fork. "Of course they do," returned the man. "Sometimes you have it quite chilly after a hot day. Other times you have it suffocatin'--like the Black Hole of Calcutta--as it'll be to-night."