"There is not much to see." I was saying the very words when with a crash a wall on the opposite side of the Cours seemed to crumble in upon itself. There was a jet of flame, a rain of stones, which reached half-way to the defences of the works, and then a gap, dark and vague in the veiled moonlight. "That was dynamite," said Rhoda Polly, "though the report was not loud. There is, quarrymen say, a silent zone in which the explosion is not heard. We must be just on the verge of that. I wonder if there is more to come." We waited--I straining my eyes into the darkness and seeing nothing. The moon did not reach down into the gulf which the explosion had created. But I was vaguely conscious of shapes that moved and of a curious crushing noise like that of the steam-roller upon the fresh macadam of a roadway in the making. But though Jack Jaikes came up to see for himself, none of us could make out anything--till Rhoda Polly, whose eyes were like those of a cat, made a telescope of her hands and after a long look whispered eagerly, "I see something they have got in there. It is like a bear on end--you know--when it is dancing." "Try again, Rhoda Polly. Try the night-glass!" "I can do better without it, Jack Jaikes--yes, I see better now--it is like a big boiler for washing clothes or boiling pig's-meat with the mouth tilted towards us. It looks as if it were mounted on a kind of cradle!" The words were hardly out of her mouth when Jack Jaikes exclaimed, in a voice which might have been heard half across the wide oblong of the Cours, "A mortar--I never thought of that--they have got a mortar. They were clearing a way for using it--at short range too. They can plug us anywhere now." He sprang towards the Morse telegraph, but he did not reach it. A concussion and a roar shook the tower to its base. I saw the flame shoot out a yard wide from the gap in the defence wall. Our main gate and part of the rampart to the right had been badly smashed, quite enough for a determined storming party to penetrate if the new gun made any more successes. "They are firing solid shell at us," said Jack Jaikes, frantically manipulating the keys of the telegraph instrument. "Now I must get a gun to play upon them. It will need something big, for though we can scourge their gun emplacement with mitraille fire, the merit of their plan is that the gunners lie hid in a ditch. Only one man, or two at most, are needed to slip round and drop in the charge and shell." "I see them," said Rhoda Polly, pointing where we saw only blank darkness. "Give me a rifle, Jack Jaikes. I believe I can pick that man off!" "You shall have number 27, Rhoda Polly, the best ever made. Oh, if only I had eyes like you!" Jack Jaikes groaned aloud, and Rhoda Polly settled herself behind the sand-bags. But she glanced up almost instantly. "He is gone!" she said. "Then look out!" cried Jack Jaikes.