Curiosities of Science. 1 7 



The power of gravity at two miles distance from the earth is 

 four times less than at one mile ; at three miles nine times 

 less, and so on. It goes on lessening, but is never destroyed. 

 Notes in various Sciences. 



VARIETIES OF SPEED. 



A French scientific work states the ordinary rate to be : 



per second. 



Of a man walking 4 feet. 



Of a good horse in harness 12 



Of a rein- deer in a sledge on the ice . . . 26 

 Of an English race-horse . . 43 



Of a hare 88 



Of a good sailing ship 19 



Of the wind 82 



Of sound 1038 



Of a 24-pounder cannon-ball .... 1300 



LIFTING HEAVY PERSONS. 



One of the most extraordinary pages in Sir David Brewster's 

 Letters on Natural Magic is the experiment in which a heavy 

 man is raised with the greatest facility when he is lifted up the 

 instant that his own lungs, and those of the persons who raise 

 him, are inflated with air. Thus the heaviest person in the 

 party lies down upon two chairs, his legs being supported by 

 the one and his back by the other. Four persons, one at each 

 leg, and one at each shoulder, then try to raise him the per- 

 son to be raised giving two signals, by clapping his hands. At 

 the first signal, he himself and the four lifters begin to draw a 

 long and full breath ; and when the inhalation is completed, or 

 the lungs filled, the second signal is given for raising the per- 

 son from the chair. To his own surprise, and that of his bearers, 

 he rises with the greatest facility, as if he were no heavier than 

 a feather. Sir David Brewster states that he has seen this 

 inexplicable experiment performed more than once; and he 

 appealed for testimony to Sir Walter Scott, who had repeatedly 

 seen the experiment, and performed the part both of the load 

 and of the bearer. It was first shown in England by Major H., 

 who saw it performed in a large party at Venice, under the di- 

 rection of an officer of the American navy.* 



Sir David Brewster (in a letter to Notes and Queries, No. 143) 

 further remarks, that " the inhalation of the lifters the moment 

 the effort is made is doubtless essential, and for this reason : 

 when we make a great effort, either in pulling or lifting, we 

 always fill the chest with air previous to the effort ; and when 



* This curious fact was first recorded by Pepys, in his Diary, under the date 

 31st of July 1665. 







