450 MR MILNE ON THE DRYING UP OF THE 



how little the various observers, or even scientific men, were agreed as to the true 

 explanation. 



When the phenomenon was repeated last November, though on a scale much 

 more striking than on any former occasion, the same speculations were excited, 

 and the same diversity of opinion prevailed, as had previously existed. It is of 

 course unnecessary to advert to all the theories which were started, but the most 

 plausible of them may be noticed. 



Some persons conceived, that the strong south-easterly wind which blew du- 

 ring the night of the 26th and following morning, was of itself sufficient to pro- 

 duce the effect. It was observed that the Teviot and the Nith flowed, for the 

 greater part of their courses, in an easterly direction, and that the Clyde, in the 

 higher part of its course, likewise flowed in this direction ; so that the easterly 

 gale blew up against these streams, and might have obstructed, if not stopped in 

 some places, the flowing of their currents, and thus have cut off the usual supply 

 of water from the lower parts of the river. 



Others thought, that the frost which prevailed during the night of the 26th, 

 and morning of the 27th, must have frozen up the springs and rivulets at the 

 sources of the rivers ; or that it, at all events, stoJ)ped the flowing of the current 

 in those parts where there were caulds or damheads, — by forming a barrier of ice 

 along the top of them. 



Others, again, imagined, that the phenomenon might have been caused by an 

 earthquake, or rather by the widening of the natural fissiu'es and rents abounding 

 in strata, which is known to take place during an earthquake. This opinion was 

 suggested by the fact, that, in Italy, the temporary disappearance of rivulets, 

 even of considerable size, is not an unfrequent occurrence before or during an 

 eruption. Professor Phillips, in his article on Geology, published in the last edi- 

 tion of the Encyclopaedia Britannica, mentions as the effect of volcanic agency in 

 England, that, " in (the year) 1110, the Trent was dry at Nottingham for a whole 

 day ; and that, in 1158, the Thames was dry at London."— (P. 245-6.) A similar 

 phenomenon was stated to have occurred in Scotland on the 6th January 1787, 

 on which day the shock of an earthquake was violently felt in the parishes of 

 Strathblane and Campsie, and a large district of country in the west of Scotland. 

 On the same day, it appears that the Woodhead bum, which runs through the 

 parish of Strathblane, and there turns a mill, left its channel dry for a short in- 

 terval ; and, what is still more remarkable, there was likewise on that day a stop- 

 page and desiccation of the Clyde. 



In farther explanation of this last theory, I may here allude to what is 

 familiar to all geologists, that, in secondary rock districts, and especially those 

 occupied by carboniferous strata, there is hardly an acre which is not inter- 

 sected by numerous cracks or fissures, reaching from the surface to an unfa- 

 thomable depth, and varying in width from a few inches to many feet. There 



