48 REPORT — 1870. 



Council Meeting of 4th February, 1870, 



" Communication from British Association. — It was agreed that the fol- 

 lowing gentlemen be appointed a Committee to act with the Committee of 

 the British Association with a view to the carrying out the recommendations 

 contained in the Report of the Committee on a communication from the 

 British Association respecting the qualities of Ships : — ^Professor Rankine, 

 Jas. R. Napier, and J. G. Lawrie." 



(Extracted.) J. R. Smith, Secretary. 



W. H. Millar. 



Report of the Committee on Earthquakes in Scotland. The Committee 

 consists of Sir W. Thomson, M.A., LL.D., F.R.S., D. Milne- 

 Home, F.R.S.E., P. Macfarlane, and J. Bryce, M.A., LL.D., 

 F.G.S. (Reporter). 



The instruments belonging to the Association, set up at Comrie, are in a 

 satisfactory condition, and the records are duly kept. It has, however, been 

 of late forced upon the attention of the Committee that most probably the 

 Seismometer is not sufficiently delicate to indicate the very slight shocks 

 which are now of frequent occurrence, while the concave disk, on which the 

 pencil-point traces the direction of the shock, is inconveniently high for fre- 

 quent observation. Under these circumstances some simpler contrivance, and 

 one which shall give less trouble to the observer, is much to be desired. 

 The Committee is jiow considering how this can be best accomplished, with 

 special reference to the registration of slight shocks by some method of 

 magnifying the effect. Care will be taken that the instrument be thoroughly 

 tested before being set up at Comrie, and that the cost be as small as pos- 

 sible. In the autumn of last year there were several slight shocks, and, 

 apparently in connexion with them (though it would be rash to speak posi- 

 tively on this point), a remarkable movement of the waters of Loch Earn, 

 though the shocks were not felt at that distance from Comrie. The matter 

 being reported to me, I went into the district soon after, and collected the 

 most satisfactory evidence of the movement in question. It occurred on 

 several occasions in the months of August and September last ; but the most 

 remarkable and most completely attested case was that of the 15th day of 

 September, between the hours of 10 a.m. and noon. The day was calm and 

 misty, with a slight air up the lake from the east, and the water conse- 

 quently quite unruffled. At the east end chiefly the movement was observed. 

 The water rose slowly, in successive low, broad undulations, to the height of 

 from 2 to 6 feet, along the shelving beach, and as slowly subsided, the undu- 

 lations continuing through the two hours of the forenoon above mentioned. 

 There was nothing sudden or disturbed in the movement ; in so far it was 

 unlike the effect of earth-waves passing into water ; it resembled more the 

 movements which are at rare intervals noted in the lakes of Switzerland, and 

 may be the effect of subterranean movements at great distances. Instruction 

 had been given for the careful observation of any such occurrences in future. — • 

 On the 29th of April last, about 11 p.m., a pretty smart shock of earthquake 

 was felt over the district, to the extent of 10 miles along the valley of the 

 Earn, and about half that distance in a transverse direction. There were 



