i897-] Praeger. — Bog-bursts — ReceJit Disaster, Co. Kerry. 159 



influence of severe changes of climate ; the latter consist of 

 alternating layers more or less highly decomposed. The 

 different layers have different saturation-limits for water, and 

 these limits once attained never alter. There is no vertical 

 movement of water through a bog. This view, the author 

 asserts, stands in complete opposition to statements made by 

 older writers as to the absorption by bogs of from 50 to 90 per 

 cent, of their bulk of water. In support of his contention that 

 peat bogs are impermeable, he appeals to pools on their 

 surface, often 5 to 10 feet in depth, separated by peat-walls 

 only 3 to 5 feet thick, and yet with water-levels differing from 

 each other by several feet. The dome-like form of mountain 

 bogs he regards as inexplicable, unless a high capacity for 

 water in conjunction with imperviousness be admitted for the 

 peat. Excessive rainfall accumulates in pools on bogs, which 

 are drained by surface channels. Pools only occur on bogs 

 near the wet western coast of Europe. The author makes an 

 interesting observation on the dessicating effects of sphagnum 

 on the air over mountain bogs. This is so great that on the 

 leeward of these bogs, at least in Norway and Nova Zembla, 

 an aero-xerophytic (dry air) flora occurs. 



The immediate cause of an eruption of a bog is, according 

 to Klinge, the violent irruption of water into the bog from 

 below. 



In discussing Klinge's views we may first point out that the 

 mountain bogs of this country belong to his first class — those 

 in which the decomposition of the vegetable matter increases 

 from the surface downwards. The decomposed peat is heavier 

 than water, and tends to accumulate at the bottom : the crust 

 on which the growing plants are found is lighter than water, 

 and floats on the top of the bog. It is between the crust and 

 the lower layers that we should expect the most fluid portion 

 of the bog to occur. 



We cannot agree that the crust is impermeable ; the fact 

 that bogs can be drained is opposed to such a view ; nor do 

 the pools which Klinge instances afford conclusive proof in 

 its favour ; they may be explained by a differe ce in per- 

 meability of the surrounding peat, and that they are being 

 drained of water, or have been supplied with it, it is possible, 

 at different rates. 



