Intelligence and Miscellaneous Articles. 153 



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wire, suspended and previously heated. The motion, in this case, 

 is produced simply by the vapour of water disengaged around the 

 floating body. It is this hypothesis which very readily explains the 

 suspension of rotation when a drop of oil is thrown on the surface 

 of the water, or when it is covered with a plate of glass. 



The following are the most convincing facts in favour of this ex- 

 planation of the motion of camphor. I took rather a large piece of 

 it, in order that when put upon water its motion might be very slow. 

 I afterwards put the glass in which the experiment was made under 

 the receiver of the air-pump and exhausted it. I then observed that 

 the movements of the camphor, which were at first scarcely per- 

 ceptible, become more rapid, and that they ceased when the action 

 of the pump was stopped. On allowing the air to enter, the rota- 

 tion occurred for some seconds, which was undoubtedly occasioned 

 by the agitation produced by the reentering air. Lastly, and it is 

 the most unexceptionable proof, I have observed these phenomena 

 of rotation on water in all volatile bodies. I took raspings of cork 

 and impregnated them with sulphuric aether : when placed upon 

 water these small light bodies turned very rapidly. If it be wished 

 to cause this rotation to continue for a long time, it is sufficient to 

 immerse a wire in sether, and to make the other end touch the sur- 

 face of the water ; the aether descends as by a syphon, and the mo- 

 tion is continued. 



It is, then, I think, proved that the rotation of volatile bodies is 

 owing to the currents of their vapours. I will add a word respect- 

 ing the well-known phaenomenon produced by a stick of camphor 

 immersed in water : I mean that of its being cut precisely according 

 to the line which touches the exterior surface of the liquid. It is 

 easy to prove, that of all the strata of water which are in contact 

 with the camphor, it is in the upper that the solution is greatest. In 

 fact, camphor dissolves in small quantity in water, but it is only at 

 the surface that the dissolved camphor can evaporate : this water 

 then dissolves a fresh portion, and so on repeatedly. When this 

 solution is prevented, the phaenomenon ceases to be produced. If a 

 stick of camphor be placed in a concentrated solution of potash, 

 and another in water, the latter is cut in two in three or four days, 

 and the other is not at all attacked. — Ann. de Ckim. et de Phys., 

 torn, liii.p. 216. 



ON MARGARON, STEARON, AND OLEON. 



M. Bussy prepared margaric acid by distilling suet, and purifying 

 the product by pressure and crystallization in alcohol : it melted at 

 131° Fahrenheit. This acid was preferred to that obtained by sa- 

 ponification, because the margaric acid contained no stearic acid, 

 and because it is more easily purified from the fluid products with 

 which it is mixed. 



A quantity of this acid was mixed with a quarter of its weight of 

 lime, and distilled in a retort. First a quantity of water came over, 

 and then a soft mass, from which there is obtained, by pressure, a 

 matter similar to that which the suet furnishes. The last portions 



Third Series. Vol. 5. No. 26. Aits. 1834. X 



