15S On the apparent Repulsion 



expelled by a mechanical movement, but because, in 

 striking the surface of the dish, they extend themselves 

 over it, and displace the water. If it then happen that the 

 drop of sj/irit of wine begins to touch the surrounding water, 

 an agitation is immediately seen to arise, by which the 

 water is repelled with great vivacity, and the drop of spirit 

 of wine, animated with a new expansive force, bursts its 

 limits, extends itself, and makes the water fly before it. 

 The case is the same nearly with a small bit of camphor. 

 if a small bit of this substance be placed in a pretty large 

 dish, and covered with water to the height of a line, in 

 such g. n)anncr tliat the bit of camphor may touch the bot- 

 tom of the dish, the water will be seen in a kind of contest 

 around the camphor, and the water will seem to be kept at 

 ii distance by an expansive force. All this in my opinion 

 is the effect of the attraction of surface of the spirit of 

 wine and of the oil of the camphor for the water. The 

 oil of camphor, indeed, excited to dilate itself by the at- 

 traction of the surface of the water, evaporates with asto- 

 iiishin<i; speed, and in a little time is consumed. The case 

 is the same with spirit of wine and oil of camphor ; they 

 rush on the water, extending themselves over its surface with 

 astonishing speed ; whence arises a dispersion of the water, 

 and adhesion of the spirit of wine to the bottom of the 

 vessel. ThoL accelerated evaporation of these fluids can be 

 ascribed to no other cause than to this force ; that is to 

 sav, the attraction of surface, by which the cohesion of the 

 integrant parts is overcome, and consequently the expansive 

 force of the small volatile parts which compose these fluids 

 is increased ; but I have sufficiently explained, in another 

 place, all these phEcnomena in- regard to the movements of 

 camphor on water*. 



A drop of volatile alkali or ammonia, says Draparnaud, 

 does not expel water from the bottom of a vessel like spirit 

 of w ine, because ammonia has a great affinity for water. 

 But cannot the same be said of spirit of wine ? This re- 

 ~ pulsion, however, ought to take place when the water sur- 

 rounds a dr'Sp of ammonia, as near as possible, but uithout 

 touching it ; which is not the case. 



A drop of annnonia in the middle of a stratum of spirit of 

 uine docs not expel it, and does not form the circle of 

 recession ; but a drop of spirit of wine in the middle of a 



• The Mc-Hco-Physical Journal of Pavia, Ann. Chim. ili Pavi t : 

 Opusc. scelti di Milano, and in ionnc letters acldrt-sstil ro prctlv.or Bnig- 

 rat.Ui, Ann. Cliini. di Pavia; ;ind Memoir ou Atujc-.i >;) of Surf.ttc. 

 vol. xi- of iSic Italian bocicty. 



i . Stratum 



