of this time several companies of Australian,
New Zealand and British sappers were busily but silently engaged in
mining the hills of the Messines-Wytschaete Ridge, on which were the
guns of the Germans which had been raking the troops of the Allies all
this time. Nineteen great mines which contained a total of 1,000,000
pounds of ammonite upon their completion, had been dug into the vitals
of these hills. Great charges of this new and powerful explosive had
been placed in the mines nearly one year before their completion, yet no
one except those actually engaged in the work knew of it. The secret was
kept and the troops of Australia and New Zealand worked directly beneath
the great German fortifications.

Then came the crucial moment. At exactly 3.10 o'clock in the morning of
June 7, the whole series of mines were discharged by electrical contact,
and the hilltops were blown high in the air in one terrific burst of
flame, which poured forth as from craters of volcanoes. The ground for
miles around was rocked as in an earthquake, and the roar emitted was
distinctly heard in England by Lloyd George, the Prime Minister,
listening for it at his country home 140 miles away.

A PRE-ARRANGED SIGNAL.

The explosion of the mines was a pre-arranged signal for the beginning
of a heavy shell fire by the artillery. The whole section affected by
the mines was subjected to a most intense shellfire, and following up
this death-dealing storm came the troops of General Haig, under Sir
Herbert Plumer, who finished the work of the great mines and big guns
with a brilliant charge of men, who used rifle and bayonet most
effectively. Within a few hours the whole of the Messines Ridge was
securely in the hands of the British, and they had captured 7000
prisoners and many guns. The German casualties were estimated at 30,000,
those of the British being about 10,000.

Rushing the whole sector south of Ypres, from Observation Ridge to
Ploegsteert Wood, north of Armentieres, the British forces succeeded in
capturing that position with little loss. Then came the assault of the
rear defenses, which were formed by the ridge itself. The natural
formation of the land greatly helped the Germans in arranging their
defenses, and the fighting was very fierce. The work of British troops,
in which were many Australians and New Zealanders, together with English
and Irish, all under the command of General Sir Herbert C.O. Plumer,
was given great credit i