336 



PETER GUTHRIE TAIT 



Robins, long ago, gave data from which we can assign 114 feet per second as the 

 terminal velocity of a golf ball. His experiments were all made at moderate speeds. 

 The comparatively recent experiments of Bashforth, though mainly directed to very 

 high speeds, give for speeds under 800 feet per second the means of assigning 95 

 feet per second as the terminal velocity of a golf ball. When I began to make 

 calculations on this subject, I naturally took the more recent determination as the 

 correct one ; and was thus forced to assume at least 300 feet per second as the 

 initial speed of a golf ball in order to account for some of the simplest facts. 

 I have since found that this estimate is very considerably in excess of the truth, 

 and therefore that the terminal velocity, as assigned by Bashforth's data, is con- 

 siderably too small. I still, however, think that Robins' estimate is somewhat too 

 low, so that in what follows I shall assume 108 feet as the terminal velocity for an 

 ordinary golf ball. Trifling as may appear the differences among these numbers 

 (114, 95, and 108), experiments on initial speed seem to show that, if the first were 

 correct, we ought to drive somewhat further than we do ; while, if the second be 

 correct, it is quite certain that, on the open links, considerably greater initial speeds 

 are given than any which I have been fortunate enough to measure in my laboratory, 

 though I have had the kind assistance of some of the most slashing drivers of the 

 day 1 . 



Assuming, then, 108 as the terminal velocity, it is easy to calculate by the help 

 of Bashforth's tables (which can be adapted to any amount of resistance) the 

 following sufficiently approximate results for different elevations, the initial speed 

 being assumed to be 240 feet per second. 



One feature, at least, in this table is much more consonant with experience 

 than that corresponding to the parabolic path. The ball reaches the ground in all 

 these courses with speed far inferior to that with which it started. 



1 This paragraph and the paragraph and Table following were considerably abridged in 

 the article as published in the Badminton Magazine. 



