ON THE SEICHES OF LOCH EAKN. 



485 



the viscosity, the maximum effect does not correspond to exact equality of the two 

 periods.* 



In what precedes we have already given some examples of the effect of a periodic 

 disturbing agency ; we shall now add a few more. 



17th August. — Between 13 h and 14 h (see fig. 12) a strong binodal seiche with a trinodal 

 component is worked up by resonance with the pressure disturbance shown on the 



^/utiyurttconv 30-g-os. 



/z Hts 



cm 



/3 



'4 



/S~ 



-7$: 



fluyrUo Pcrorub 3o-g- of. 



& H7'S 



/3 



/<v 



/y 



*S 



Fig. 13. 



microbarograms, which has a period of 6™ to 8 m , well marked at Killin and Lochearn- 

 head, less clearly at Ardtrostan. 



21st August (fig. 8). — At l h ll m a BT-dicrote appears; and the microbarogram at 

 Lochearnhead shows an 8 m period ; probably its scale is too small to show the 6 m period. 

 At 5 h S7 m the binodal component is much strengthened by a microbaric disturbance 

 having a period of 8 m to 8'8 m , which is very clearly seen at Killin. The uninodal seiche 

 is also present, due no doubt to the periods of 15 m to 13 m observed at Lochearnhead. 

 30th August. — Fig. 13 shows the kind of microbaric disturbance which pro- 



* See Part V., p. 514. 



