I> 1 s A r P E A 11 1 N G 0 F Ft 1 V E 11 9 . 
GG7 
In the centre of the bog, for the space of about a mile and a 
half in length, and a quarter of a mile in breadth, a valley has been 
formed, sloping at the bottom from the original surface of the bog, 
to the depth of thirty feet, where the eruption first took place. In 
this valley, or gulf, there are numberless concentric cuts, or fissures^ 
filled w'itil water nearly to the top. The valley between the edge of 
the bog and the road of Kilbride, for the length of half a mile, and 
an extent of betw'een sixty and eighty acres, may he considered as 
totally destroyed. It is covered by tolerably firm bog, from six to 
ten feet in depth, consisting at the surface of numberless green 
islands, composed of detached parts of the moory meadows, and of 
small rounded patches of the original heathy surface of the bog, 
varying from two to ten feet in diameter, which are separated from 
each other by brown pulpy bog, and the bed of the original stream 
is elevated to about eight or ten feet above its former course, so as 
to flow over the road. Beyond the road to Kilbride, the bog has 
flowed for one mile westward, and covered from fifty to seventy acres : 
in this part, the heathy patches of bog generally lessen in quantity ; 
the green islands disappear, and nothing is observed but a thin deposit, 
consisting of a granulated black bog-mud, varying from one to three 
feet in thickness. This, though destructive for the present year, 
may, when dry, be burnt, and removed for manure to the neighbour- 
ing upl ands, or left on the spot to fertilize the valley. Thus the 
whole distance which the bog has flowed is about three miles in 
length, namely, one mile and a half in the bog, and the same dis- 
tance over the moory valley ; and the extent covered, amounts to 
about one hundred and flfty acres.’’ 
Disappearing of Rivers. 
In a memoir of the Academy of Sciences, lately published, w^e have 
some curious observations and conjectures concerning the disappear- 
ing of rivers, by the Abbe Guettard. ** It is very surprising,” he 
observes, that a river in its course, which is often very extensive, 
should not meet with spongy soils to swallow up its waters, or gulfs^ 
in which they are lost i nevertheless, as there has been hitherto 
known but a small number of rivers whose waters thus disappear, 
this phenomenon has been accounted very extraordinary, both by 
the ancients and moderns, Pliny speaks of it with an energy familiar 
to him, and Seneca mentions it in his Questiones Naturales; he even 
distinguishes these rivers into two sorts,-— those that are lost by degrees, 
and those which are swallowed up all at once, or ingulphed. 
M. Guettard has undertaken to remove part of the obscurity 
attendant on this subject, by describing what he has observed in 
several rivers of Normandy, which' are lost, and afterwards appear, 
again •, these are the Rille, theTthone, the Aiire, the Sap-Andre, and 
the Drome, The three first disappear gradually, and then come in 
sight again ; the fourth loses itself entirely by degrees, but afterwards 
reappears ; the fifth loses some of its waters in its course, and ends 
by precipitating itself into a cavity, whence it is never seen to rise 
again. What seems to occasion the loss of the Rille, the lthone, and 
