vol.. XV.] PHILOSOPHICAL TRANSACTIONS. ' 145 



good land; and it is very doubtful whether that sum will reduce a bog; but this 

 is far from the fact, as most bogs would well reward the expence of draining 

 them. 



As to loughs or lakes, the natural improvement of them, is first to drain 

 them as low as possible; and then turn the residue of the water into fish-ponds; 

 by planting a few trees about them, they may be made both useful and orna- 

 mental. As to those places called turloughs, quasi terreni lacus, or land-lakes ; 

 they answer the name very well, being lakes one part of the year of considerable 

 depth, and level smooth fields the rest. There holes are in these, out of which 

 the water rises in winter, and retires again in summer ; many hundred acres 

 being drowned by them, and those the most pleasant and profitable land in the 

 country: the soil is commonly a marie, which, by its stiffness, hinders the 

 water from turning it into a bog ; and immediately when the water is gone, it 

 hardens, and becomes an even grassy field; these, if they could be drained, 

 would be fit for any use ; they would make meadow ; or bear any grain, but 

 especially rape, which is very profitable. The lakes are chiefly in Connaught ; 

 and their cause is obvious enough, it being a stony hilly country ; these hills 

 have cavities in them, through which the water passes : it is common to have a 

 rivulet sink on one side of a hill, and rise a mile or half a mile from the place : 

 the brooks are generally dry in summer; the water sinking between the rocks, 

 and running under ground ; insomuch as that in some places where they are 

 overflowed in winter, they are forced in summer to send their cattle many miles 

 for water. There is one place on a hill near Tuam, between two of these tur- 

 loughs, where there is a hole called the Devil's Mill, at which a great noise is 

 heard, like that of a water under a bridge : when there is a flood in winter, one 

 of the turloughs overflows, and vents itself into the hole, and the noise pro- 

 bably proceeds from a subterraneous stream ; which in summer has room enough 

 to vent all its water, but in winter, when rain falls, the passages between the 

 rocks cannot discharge it, and therefore it regurgitates and covers the flats. 



These turloughs are hard to drain ; being often encompassed with hills, and 

 then it is not to be accomplished : often they have a vent, by which they send 

 out a considerable stream ; and then it is only making that passage as low as the 

 bottom of the flat, and that will prevent the overflowing: it sometimes happens 

 that the flats are as low as the neighbouring rivulets, and probably they are filled 

 by them ; and then it is not only necessary to make the passage from the flat to 

 the rivulet, but also to sink the rivulet, which is very troublesome, the passage 

 to be cut being commonly rocky. 



VOL. III. U 



