ON THE SEICHES OF LOCH EARN. 



371 



difference between the air-pressure at any moment and at the moment of closing. 

 The curve in fig. 12 shows the result of making alternate limnographic and. baro- 

 o-raphic observations, and led us to a very interesting conclusion, as will be explained in 

 a later communication to the Society. 



Use of the Statoscope as a Microbarograph. — If, instead of closing the stop-cock C ? 

 we allow it to open into an india-rubber tube fitted with a piece of thermometer tube 

 of a proper length and bore, the statoscope becomes a microbarograph, and gives records 



Fig. 13. 



similar to the Dines-Shaw instrument, with the advantage of an opener time-scale and 

 greater portability, but the disadvantage of running for a much shorter time. 



Use of Highly Portable Limnographs in Seiche Surveying. 



There can be no doubt that the quickest method of making a survey of the seiches 

 of a lake would be to use a couple of highly portable self-recording limnographs, each 

 magnifying the range of the seiches by say, 4, and having a time-scale of, say, 5 mm. 

 to a minute. By using one very portable self-recording instrument along with an 



