In all of the campaigns in which the Anzacs have participated their work as sappers has been a feature. Sappers, by the way, are those men who, in modern warfare, burrow in the earth, planting mines, digging trenches, dugouts and fortifications. The Australians are fitted for this work for a large percentage of them had civil experience in the mines, and on extensive contract and excavation work. AUSTRALIAN AND NEW ZEALAND SAPPERS. Probably one of the most effective attacks of the English against a German stronghold in Belgium was made possible through the work of the Australian and New Zealand sappers. That was the blowing up of the Messines Ridge in June, 1917. In this action the Anzac shone in a manner that can never be forgotten. On June 7, 1917, the British, with one terrible stroke, tore asunder the strong German position south of Ypres. This stroke was in a little corner of Belgium, where the armies of the Allies had successfully outgeneralled the enemy for two and a half years. During almost two years 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.