94 



MR RUSSELL'S RESEARCHES IN HYDRODYNAMICS. 



value of the following Table. To remove the appearance of affectation of supe- 

 rior accuracy, where the nature of the indications, and the subject of measure- 

 ment, would not bear out the degree of apparent precision given by such figures, 

 fractions of a pound have been omitted, as the experience of making these expe- 

 riments has shewn me that errors of directing the vessel, and the resistance of 

 the helm, must have affected the result to an amount gi-eater than any such frac- 

 tion. In general, I have endeavoured to render the apparent precision of number 

 indicated a measure of the precision of the observation, having never allowed the 

 indications to be read off with greater minuteness than the total of the probable 

 error. 



The following Table; formed from the Experiments of 1834, Avith the Skiff, re- 

 gards only the resistance of the vessel. The vessel was steered within three feet 

 of the line of motion of the horse, the line was sixty feet long, reducing the cor- 

 rection for the deviation of the line of traction from the line of the keel to a very 

 small quantity ; this correction has not been applied in the following table, which 

 contains the experiments exactly as made. The fii'st column gives the time of 

 describing 500 feet ; columns second and third giving the velocity ; the fourth 

 column contains the mean motive force applied at these velocities; the fifth 

 column shews the number of feet described from which the observations have been 

 drawn ; and the sixth column is a table of squares of velocities, and affords the 

 means of comparing the law of the squares with the real laAv of resistance. 

 From the small immersion of the Skiff, her wave was small, and the velocity of a 

 wave equal to that generated by her motion is given in the table as observed by 

 experiment. 



The Skiff. 



Time to 



500 Feet. 



Velocity in 

 Feet. 



Miles per 

 Hour. 



Motive Power 

 in lbs. 



No. of Expe- 

 riments made. 



Ratio of 

 Squares of 

 Velocities. 



Remarks. 



s. 



113 

 85 

 80 

 66 

 64 

 60 

 59 

 57.5 

 58 

 56.5 

 53 

 48.5 

 47 



4.42 



5.88 

 6.25 

 7.58 

 7.81 

 8.33 

 8.45 

 8.62 

 8.69 

 8.85 

 9.43 

 10.30 

 10.64 



3.0168 

 4.0096 

 4.2613 

 5.1652 

 5.3248 

 5.6816 

 5.1111 

 5.8789 

 5.9288 

 6.0335 

 6.4318 

 7.0290 

 7.2534 



lO.l 



17.6 



18.6 



26.7 



27.5 



39.0 



48.0 



50.2 



51.2 



55. 



61. 



79. 



82.5 



Five 



Three 



Three 



Seven 



Four 



Four 



Two 



Four 



Six 



Nine 



Five 



Seven 



9.1011 

 16.095 

 18.158 

 26.669 

 28.353 

 32.280 

 33.882 

 34.561 

 35.151 

 36.403 

 41.368 

 49.407 

 52.612 



Weight of Skiff 3 cwt. 

 941bs.; load in Skiff 

 7 cwt. 26 lbs. To- 

 tal 1240 lbs. Length 

 of Skiff 31 feet 3 

 inches, gunwale 30 

 feet 3 inches keel ; 

 maximum breadth 4 

 feet 2i inches. 



/Velocity of Wave 

 J 2 inches high, 

 j = 10.853 feet, 

 ' = 7.3997 miles. 



42 



40 



37.2 



35 



33.3 



29 



11.90 

 12.50 

 13.44 

 14.28 

 15.01 

 16.90 



8.1168 

 8.6228 

 9.1642 

 9.7403 

 10.2370 

 11.7555 



82.5 

 81.1 

 86.3 

 89.2 



107. 



111. 



Three 



Nine 



Twenty-one 



Twelve 



Nine 



Six 



65.882 

 72.368 

 83.982 

 94.873 

 107.86 

 188.19 



