524> Mr. A. J. Robertson on the Positive Wave of Translation. 



Column A is the mean height of the wave crest =a-\-2k. 

 Column B, selected examples from which A is taken. 

 Column C, depth of fluid in repose in inches =a. 

 Column D, the height of waves in inches = 2k. 

 Column E, the velocity of wave observed 



Column F, by formula a /^JL— . {a-\-2~k)g 



Column G, difference between E and F 



, in feet per 

 second. 



Small Waves.' 



A. 



B. 



C. 



D. 



E. 



F. 



G. 



No. 



1075 



1-05 & MO 



1-000 



075 



1-670 



1-73 



•06 



1 



1-3 



13 



1150 



•150 



1-810 



1-927 



•117 



2 



3-17 



309 & 3-23 



2-963 



•207 



2-860 



2-965 



105 



3 



3-36 



3-32 & 3-40 



3-080 



•280 



2-960 



3068 



•108 



4 



4-16 



40 &4-31 



3-903 



•256 



3-310 



3-390 



•080 



5 



5-34 



5-20 & 5-5 



5-088 



•252 



3-758 



3-829 



•071 



6 



6-52 



6-4 &6-G5 



6-220 



•304 



4094 



4-232 



•138 



7 



7-51 



7-42 & 77 



7040 



•474 



4-406 



4-563 



•157 



8 











Average . . . 



.. 1045 





Large Waves. 



A. 



B. 



C. 



D. 



E. 



F. 



G. 



No. 



1-20 



1-20 



100 



•200 



1-760 



1-880 



•120 



1 



1-62 



1-62 



1-300 



'320 



2060 



2-209 



•149 



2 



219 



219 



1-900 



•290 



2-300 



2-514 



•214 



3 



3-38 



3-35-3-41 



2-960 



•420 



3010 



3116 



•106 



4 



3-55 



3-5 -3-61 



3-020 



•532 



3080 



3-219 



•139 



5 



3-83 



3-69-3-97 



3-007 



•830 



3-252 



3-419 



•167 



6 



4-53 



4-4 -4-75 



3-910 



•625 



3-505 



3-622 



117 



7 



5-21 



5-21 



3-870 



1-340 



3-820 



4-030 



•211 



8 



5-76 



5-61-5-82 



5-070 



•692 



3-970 



4-063 



•093 



9 



6-24 



615-6-40 



5-080 



1160 



4170 



4-318 



•148 



10 



6-69 



6-69—7-20 



6034 



•823 



4-262 



4-378 



•116 



11 













Average... 



... -143 





Or, leaving out the two errors *214 and *211, the average 

 would be '128. In the eighth example, the error might have 

 been attributed to the circumstance of the wave being higher; 

 but the error in the third example is as great, although the 

 height of the wave is only *29. The twelfth example, given 

 by Mr. Scott Russell, is evidently anomalous. 



From this comparison it appears that the average difference 

 between the velocity observed and that assigned by the for- 

 mula is scarcely more, in the case of the small waves, than 



