The four people standing beneath the portico of the police-station remained as if spell-bound for a full moment after the sudden flash and the sudden roar. Betty Fosdyke unconsciously clutched at Lord Ellersdeane's arm: Lord Ellersdeane spoke, wonderingly. "Thunder?" he exclaimed. "Strange!" Easleby turned sharply from Starmidge, who, holding by one of the pillars, was staring towards the quarter of the Market-Place, from whence the scream of dire fear had come. "That's no thunder, my lord!" he said. "That's an explosion!--and a terrible one, too! Are there any gasworks close at hand? It was like----" Polke came rushing out of the lobby behind them, followed by some of his men. And at the same instant people began running along the pavements, calling to each other. "Did you hear that?" cried the superintendent excitedly. "An explosion! Which direction?" Starmidge suddenly started, as if from a reverie. He put up his hand and wiped something from his cheek, and held the hand out to a shaft of light which came from the open door behind them. A smear of blood lay across his open palm. "A splinter of falling glass," he said quietly. "Come on, all of you! That was an explosion--and I guess where! Get help, Polke--come on to the Cornmarket! Get the firemen out." He set off running towards the end of the Market-Place, followed by Easleby, and at a slower pace by Lord Ellersdeane and Betty. Crowds were beginning to run in the same direction: very soon the two detectives found it difficult to thread a way through them. But within a few minutes they were in the Cornmarket, and Starmidge, seizing his companion's arm, dragged him round the corner of Joseph Chestermarke's house to the high garden wall which ran down the slope to the river bank. And as they turned the corner, he pointed. "As I thought!" he muttered. "It's Joseph Chestermarke's workshop! Something's happened. Look there!" The wall, a good ten feet high on that side, was blown to pieces, and lay, a mass of fallen masonry, on the green sward by the roadside. Through the gap thus made, Starmidge plunged into the garden--to be brought up at once by the twisted and interlaced boughs of the trees which had been lopped off as though by some giant ax, and then instantaneously transformed into a cunningly interwoven fence. The air was still thick with fine dust, and the atmosphere was charged with a curious, acid odour, which made eyes and nostrils smart. "No ordinary burst up, this!" muttered Starmidge, as he and Easleby forced their way through branches and obstacles to the open lawn. "My God!--look at it! Blown to pieces!" The two men stood for a moment staring at the scene before them, as it was revealed in the faint light of a waning moon. Neither had ever seen the effect of high explosives before, and they remained transfixed with utter astonishment at what they saw. Never, until then, had either believed it possible that such ruin could be wrought by such means.