"A cloud! a real cloud!" shouted Joe at this moment, for that piercing eyesight of his beat all the glasses. And, in fact, a thick bank of vapor, now quite distinct, could be seen slowly emerging above the horizon. It appeared to be very deep, and, as it were, puffed out. It was, in reality, a conglomeration of smaller clouds. The latter invariably retained their original formation, and from this circumstance the doctor concluded that there was no current of air in their collected mass. This compact body of vapor had appeared about eight o'clock in the morning, and, by eleven, it had already reached the height of the sun's disk. The latter then disappeared entirely behind the murky veil, and the lower belt of cloud, at the same moment, lifted above the line of the horizon, which was agai