94 



MR RUSSELL'S RESEARCHES IN HYDRODYNAMICS. 



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

 rior accm-acy, 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 shewai me that en-ors of directing the vessel, and the resistance of 

 the hehn, 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, with the Sldff", 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 law 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. 



