Rotation of Liquids. 



89 



we repeated a few of the experiments,* sufficient to exemplify the 

 phenomena, and to demonstrate their cause. 



The 6rst of M. Thayer's experiments was to suspend a jar or 

 phial containing two liquids of different specific gravities, and cause 

 it to oscillate like a pendulum, in which case, even if the oscillations 

 be small, the heavier liquid will be found to undergo a considerable 

 variation in the position of its surface, so much indeed, as to render 

 the surface of separation of the two liquids greatly inclined to the 

 horizontal position, and sometimes even so much as to divide the li- 

 quid superficies, and to form it in part of the heavier, and in part of 

 the lighter of the two liquids. If the oscillations become so great as 

 10 be ultimately changed into a complete rotation, the heavier liquid 

 will, when the vessel is in the upper part of its course, be found at 

 the surface, and the lighter at the bottom, (then the highest part,) of 

 the vessel. 



Dr. Franklin made use of the first part of this experiment to illus- 

 trate his idea of the effect of oil upon the surface of the ocean. 



It is represented by 

 figures a, h, and c, the 

 first supposed to be at 

 rest, and the second 

 and third in different 

 parts of their oscilla- 

 tion. O and W repre- 

 sent respectively por- 

 tions of oil and water, 

 but any other two li- 

 quids of unequal speci- 

 fic gravities which will 

 remain separate, will 

 answer the purpose ■ 

 equally well. The arcs ^/ 

 described by the water l"' 

 being larger than those 

 described by the oil at 

 the same lime that its 

 specific gravity is great- 





I 



'W ■': 



S^;*^ 



^ 



■1^^ 



* These experiments were repeated at the monthly meeting of the Franklin In- 

 stitute, in May, 1834. 



