577 



IX. That the jets or films of camphor can be rendered sensible 

 by various means as by fixing the camphor partly submerged in 

 water, ancj dusting the surface lightly with lycopodium powder : a 

 series of horizontal currents produced by the films will then be 

 made visible, which films or jets cause the camphor, when free 

 to move, to rotate on a vertical axis. 



X. That the motions of the fragments of camphor on water are 

 greatly influenced and complicated by their mutual attraction and 

 by the attraction of the sides of the vessel. 



XI. That the film of camphor diffused over the surface of the 

 water is very volatile, disappearing as fast as it is formed, chiefly into 

 the air, only a very small portion being retained by the water. 

 Hence camphor wastes away much more quickly at the surface of the 

 water than in water alone or in air alone, because at the surface the 

 film is being constantly formed at the expense of the camphor, and 

 is spread out to the united action of air and water. 



XII. That whatever interferes with evaporation lowers or arrests 

 the motions of the camphor and the allied phenomena ; so, on the 

 contrary, whatever promotes evaporation exalts these phenomena. 

 Effects which are displayed with great energy on a bright and sunny 

 day, are produced either sluggishly or not at all on a wet, dull, or 

 foggy one. 



XIII. That a fixed oil forming a film on water will displace the 

 camphor film, and so permanently arrest the motions of the cam- 

 phor ; but a volatile oil will only arrest the motions while it is pre- 

 sent and undergoing evaporation. 



XIV. That the presence of the camphor film on water will, in 

 gome cases, prevent the formation of other films, the liquids that 

 would otherwise form them remaining lenticular. 



XV. That the camphor film, and other films, in many cases repel 

 each other on the surface of water. 



XVI. That the motions of camphor on the surface of water are 

 accelerated by the action of the vapour of benzole, and some other 

 volatile substances : such vapours, condensing in the liquid form on 

 the camphor, and then being diffused by the adhesion of the water, 

 react on the camphor. 



VOL. xi. 2 T 



