498 PROFESSOR CHRYSTAL 



be under the mark if we admit that the statolimnograph magnified the range of these 

 vibrations three times. The obvious conclusion is that there was no disturbance of the 

 atmospheric pressure of an order sufficient to cause directly the embroidery observed on 

 the limnogram. It follows that it must have been due to some cumulative atmo- 

 spheric cause whose action originated at a distance from the observers, and I am inclined 

 to look for this cause in the surface waves, solitary or periodic or quasi-periodic, caused 

 by the heaping action of the wind. It is, of course, obvious that such action as this 

 would be screened off by a promontory or an island, and would be most marked at the 

 windward end of a lake. This cause was suggested, under the name of Windstau, by 

 Endros in his classical memoir on the complicated seiches of the Chiemsee, which has 

 done so much to enlarge our knowledge of lake oscillations. 



Before concluding this part of my report, 1 must say a word or two in recognition 

 of the services of those who assisted us in our seiche survey. 



In the first place, thanks are due to Mr Laurence Pullar, whose generosity 

 furnished the greater part of the money required for our undertaking. 



We have also to thank the Government Grant Committee of the Royal Society of 

 London, for giving us a grant for the hire and instalment of meteorological apparatus ; 

 and Mr W. N. Shaw, Director of the Meteorological Office, for much sympathy, which 

 went the length of a visit to Loch Earn, and even to manual assistance in the erection 

 of some of our instruments. 



To the constructive skill and practical scientific capacity of Mr James Murray we 

 owed the overcoming of many of our early difficulties, and also some of our best 

 observations. 



Messrs P. White and W. Watson, who were specially attached to the Lake 

 Survey for our work during August and September 1905, worked throughout with the 

 greatest zeal and good judgment. Most of the meteorological observations and nearly 

 all of the later observations with the index limnographs were made by them. 



Mr Macdonald, Schoolmaster, and Mr Thornton, Postmaster, Lochearnhead, and 

 also the Postmistress at St Fillans, kindly assisted us by taking charge of barographs ; 

 and the Stationmasters at Lochearnhead and Balquhidder did their best to give us 

 correct time. 



The proprietors of the shores of Loch Earn most courteously allowed us to instal 

 our fixed instruments in the most suitable places. In particular, Colonel Stewart of 

 Ardvoirlich not only allowed us to put up our limnographs on his property, but 

 permitted us to cut wood for the staging, and furnished us with information regarding 

 the daily rainfall at Ardvoirlich. 



The photographic reproduction of the figures in this report was in many cases 

 difficult, owing to the faintness of some of the records, in all cases tedious, owing to 

 the troublesome adjustment of scale. The patient intelligence devoted to this part of 

 the work by the firm of Hlslop & Day deserves the highest praise. 



