Frederick Guthrie on Stationary Liquid Waves. 291 



The depth of the water in it was 290 millims., and its temperature 

 16° C. Being set in binodal motion, the gauge was put in and 

 the amplitude allowed to subside to 30 millims. at the centre. 

 In the 1st minute 122 recurrences were counted. 



„ 2nd „ 122-5 



„ 3rd „ ^ 122 

 There was an interval of 10" between the 1st and 2nd minute, 

 and an interval of 15" between the 2nd and 3rd minute. The 

 amplitude of motion at the centre had now sunk to less than 1 

 millim. This shows that in this system amplitude or wave- 

 height is without sensible influence. This is confirmed by the 

 results of the following experiment, in which the initial ampli- 

 tude at the centre was again 30 millims., and in which the num- 

 ber of pulsations made in 4' was counted in four experiments. 



(1) Amplitude at first at centre 30 millims. ; in 4' there were 490 



(2) „ „ „ „ 489-5 



(3) » „ „ „ 489-5 

 W „ „ „ „ 489 



or B n mean in 1' = 122*4. 

 § 4. Effect of Temperature. — The water in vessel B was now 

 heated to 41° G., or through 25° C. It had the same depth as 

 before. The following three observations were made : — ■ 



(1) In 3' there were 367 pulsations. 



(2) „ „ 366 



(3) In 3' 25" „ 420 



which gives for 1' the mean number 122*4, precisely the same 

 result as for T = lb°. Temperature, therefore, has no appreciable 

 influence, and its variation may be neglected. 



§ 5. Effect of Depth. — For the examination of this influence 

 the vessel B was again employed. The maximum amplitude at 

 the centre was in all cases, at the beginning, about 30 millims. 







Number of 





Depth. 



Time. 



pulsations 

 counted. 



n. 



millim. 









2'JO 



4 



489-5 



1224 



270 



4 



490 



1225 



250 



3 



368 



1226 



230 



4 



490 



122-5 



210 



3 



308 



122-6 



190 



3 



367 



1223 



170 



3 



367 



1223 



150 



3 



366 



1220 



130 



3 



361-5 



121 5 



110 



3 



360 



1200 



90 



2 



234 



1170 



70 



2 



225 



112-5 



50 



1 



102 



102 



U2 



