220 Proceedings of the Boyal Physical Society. 



The following communications were read : 



I. On the Poiuer of Bainfall in Denudation, as illustrated hy 

 the Bavages of the Flood of August 28, 1877, on the 

 Ochils, from Tillicoultry to Muchhart, heyond Dollar. 

 By Andeew Taylor, Esq. 



The August of 1877 exhibited on the east of Scotland 

 most of the strange meteorological phenomena of that abnor- 

 mal year in its weather relations. There were fifty-eight and 

 a half hours less of sunshine than in average years. The 

 temperature in Scotland was greatly below the average, and 

 there was a very large rainfall seen over the width of eastern 

 Scotland, though local in its manifestations, and extending 

 in Edinburgh to betwixt 200 and 300 per cent, above the 

 average. The month closed in the east of Scotland in 

 showers, and on the 28th the casualty noted in our title 

 occurred, distracting the attention of the readers of the daily 

 newspapers from Eastern war complications by the ruin of 

 roads and bridges, the temporary blocking of the local rail- 

 way, and the sad loss of two lives it occasioned. Some 

 concomitant geologic phenomena attending this flood deserve 

 a more permanent record. 



Mr Buchan has shown in a paper, read subsequently to 

 this one, that the observations of rainfall by the observers of 

 the Scottish Meteorological Society demonstrate the physical 

 features of Scotland affect its rainfall. The area of flood 

 ravages was confined to those six or seven miles, from the 

 pool of Muckhart to Tillicoultry, where the Devon turns 

 almost at right angles from its eastern windings to join the 

 Forth. The Ochils here take that steep wall-like aspect 

 which is their prominent characteristic from the railway 

 carriage on the way to Stirling. Several small mountain 

 streams descend the steep gradients almost at right angles to 

 the course of the Devon, as at Tillicoultry, from 2094 feet 

 at the Law Hill, to the 200 feet contour line which follows 

 the course of the Devon from Muckhart, and it was down 

 these burn courses most of the damage was done. It had 

 rained all the previous evening, and on the early morning of 



