But the sub. was wrong in his surmise. Nemesis, in the shape of a drifting German mine, had overtaken the air-raider of the night. In turning, the trawler had fortunately missed the latent weapon by a bare yard, while the airship, having to describe a wide circle, had brought the submerged gondola in contact with the sensitive horns of the mine with disastrous results.

"After all, there's some consolation," thought Tressidar as he went below to write out his report. "There's one Zeppelin the less."

CHAPTER XII

AN OCEAN DUEL

Midway between the coasts of Norway and Iceland and at less than three degrees south of the Arctic Circle the British light cruiser "Heracles" was on patrol duty. She was one of a chain of swift vessels spread out betwixt Iceland and Cape Wrath in order to tighten the net that was being cast about Germany's sea-borne trade.

Germany's mercantile fleet had long since been swept off the five oceans, but her sea-borne trade still continued. Thanks to the incapacity of a certain section of the British Government to grasp the necessity for a stringent blockade, neutrals, bought by Teuton gold, were actively engaged in importing enormous quantities of goods, more than ten times the amount needed for their own consumption, and were waxing rich by means of the inflated prices that the Huns were forced to pay in order to obtain the necessaries for carrying on the war.

But at last, owing to popular clamour rather than to the inclination of the civil authorities, the British Government had been forced to action. The great silent navy, that for months past had had to overhaul ship after ship without being allowed to detain what were obviously supplies intended for Germany, was now unfettered.

"Stop everything," was the order. The "rights" of petty neutral States—parasites upon the belligerent nations—had to be waived if the Great War was to be won by the Entente Powers.

The "Heracles" was a vessel of 4,300 tons, mounting two 6-in. guns and eight 4.7's. Her speed was nineteen knots—sufficient to overhaul any merchant craft likely to be met with in high latitudes. She was manned by the officers and crew of the late cruiser "Pompey."