59 8 



THE POPULAR SCIENCE MONTHLY. 



destroyed or diminished, while that forward continues in full 

 force to draw the boat onward. If a bit of camphor be substi- 

 tuted for the alcohol, its vapor has the same effect upon the ten- 



Fig. 6.— Tin Boat sailing around on Water bt the Aid of a Bit op Camphor. 



si on, and the boat may be made to sail regularly, with consider- 

 able speed, for hours. The experiment is made more spectacular 

 by furnishing the boat with a mast carrying a flag. 





Fig. 7.— Movements op Fine Grains op Camphor on the Surface op Mercury. 



In another experiment described by M. Devaux, a few granules 

 of camphor are sprinkled upon mercury, and breathed upon till a 

 kind of lye is formed, when a multitude of long-tailed " tadpoles " 



