ON SHIP WAVES. 475 



Scott Russell, in devising these experiments, 

 adopted methods for accurate measurement in 

 order to work out the theory of those results, the 

 general natural history of which he had previously 

 observed. 



I will now read certain results from Scott 

 Russell's paper that I think are interesting. The 

 depth of the canal at the experimental station 

 was about 4 or 5 feet on an average ; it was really 

 5 \ feet in the middle, but a proper average depth 

 must have been about 4! feet, because Scott 

 Russell found by experiment that the natural 

 speed of the long wave was about 8 British statute 

 miles an hour or 12 feet per second. Here then 

 are some of the results. The Rait/i, a boat weigh- 

 ing 10,239 Ibs. (nearly 5 tons), took the following 

 forces to drag it along at different speeds : at 

 472 miles an hour 112 Ibs. ; at 5^92 miles an hour 

 261 Ibs. ; and at 6*19 miles an hour 275 Ibs. There 

 is no observation at the critical velocity of about 

 8 miles an hour. The next is at 9*04 miles an 

 hour, and the force is 250 Ibs., as compared with 

 275 Ibs. at 6*19 miles an hour. Then at a higher 



