262 THE FOREST LANDS OF FINLAND. 



used. In despite of all these difficulties the work advanced 

 rapidly. On the 27th of May a great piece of the dyke 

 broke off from the bottom with a fearful crash it was 

 believed that the whole was about to break up, or to rise 

 in a mass, and the workmen fled ; but soon they courage- 

 ously resumed their work. Similar accidents occurred 

 repeatedly ; some of the floating masses, calculating from 

 the distance at which they stood above water, must have 

 had a thickness of 70 feet submerged. On the 4th of June 

 the tunnel, 608 feet long, was cut from end to end ; but as 

 it had an elevation of twenty feet or more in the centre it 

 was necessary to level it. The weather had been cold, and 

 the lake had not yet risen to the level of the mouth of the 

 tunnel, so they continued to lower this till the 13th, the 

 day on which the flow commenced, at ten o'clock at night. 

 The lake still rose for some hours ; but next day at five 

 o'clock in the afternoon it had sunk 1 foot ; on the morning 

 of the 15th, 10 feet ; on the morning of the 16th, 30 feet ; 

 at two o'clock that day the length of the lake had shrunk 

 325 toises (nearly 2000 feet), tor the tunnel, being con- 

 tinually eaten away, lowered itself as quickly as the lake. 

 The Drause flowed, filled from bank to bank, but without 

 overflowing, and a few days more would have sufficed to 

 empty the immense reservoir. 



' But detonations in the interior of the dyke announced 

 that glagions, blocks and pillars of ice, were detaching them- 

 selves from the mass, through their low specific gravity, 

 and were thus diminishing the thickness of the dyke on the 

 side towards the lake, while the current out of the tunnel 

 was eating away this dyke on the outer side, and was 

 threatening a sudden rupture ; the danger increasing, the 

 engineer despatched from time to time expresses to warn 

 the inhabitants to keep themselves on the look-out. The 

 water began to make way under the ice, sweeping along 

 the stones and earth at its base under the tunnel ; the 

 crisis appeared inevitable and close at hand. At half-past 

 four o'clock in the afternoon a tremendous crash announced 

 the rupture of the ice-work ; the water of the lake shot 



