Mat 15, 1908] 



SCIENCE 



789 



H. J. QUAYLE 



Untveesity of Caltfobnia, 

 Beekelet 



EXPERIMENTS ON EARTH CURVATURE 



After reading my article on earth curva- 

 ture^ Mr. H. F. Dunliam, of New Tork, called 

 my attention to similar experiments reported 



by Mr. Alfred Eussel Wallace.^ A brief 

 sketch of Wallace's experiment and its results 



^ " A Simple Method of Proving that the Earth 

 is Round," Nat. Geog. Mag., XVIII., 771. 



*"My Life," Alfred Eusael Wallace, Vol. II., 

 381-393. 



may possibly be of interest to the readers of 

 Science. 



In 1870, through the medium of the public 

 press, a Mr. John Hampden wagered £500 

 that the convexity of the surface of any in- 

 land water could not be proved. Mr. Wallace 

 accepted the challenge. The old Bedford 

 Canal was chosen for the experiment and a 

 six-mile stretch between two bridges selected 

 as the site. On the higher of the two bridges 

 a white sheet, six feet long and three feet 

 wide, was fastened. Along the center of the 

 sheet parallel to the water was a six-inch 

 black band, the lower edge of which was at 

 the same height above the water as the parapet 

 of the second bridge. At the half-way point 

 a pole with two red discs, four feet apart, was 

 erected in such a way that the center of the 

 upper disc was at the same height as the 

 center of the black band. A six-inch tele- 

 scope, resting on the parapet of the second 

 bridge, was used for sighting. The result, as 

 seen through the telescope, is shown in the 

 accompanying figure. A second experiment 

 was performed with a spirit-level. 



The sequel of the experiment is almost as 

 interesting as the experiment. The referee 

 for Mr. Hampden, a devotee of the flat earth 

 school, insisted, on looking through the tele- 

 scope, that the three points were in a straight 

 line. Hampden, who refused to look through 

 the instrument, accepted the statement, al- 

 though Wallace's referee declared that the 

 curvature was shown. An umpire, chosen to 

 settle the difficulty, awarded the money to 

 Wallace. Then followed a remarkable series 

 of libels, persecutions and recriminations. As 

 late as 1885 Hampden published, among other 

 things, the statement that " no one but a 

 degraded swindler has dared to make a fraud- 

 ulent attempt to support the globular theory." 

 Wallace sums up his experience in this matter 

 thus : " . . . two law suits, the four prosecu- 

 tions for libel, the payments and costs of the 

 settlements amounting to considerably more 

 than the £500 pounds I received from Hamp- 

 den, besides which I bore all the costs of the 

 week's experiments, and between fifteen and 

 twenty years of continued persecution." 



The whole story as presented by Wallace is 



