Miscellanies. l 181 



was shocked equally with either pole* This appeared to be occa- 

 sioned by the right limb's having lost the power of receiving the sym- 

 pathetic shock. 



If a finger be dipped into a cup of water, which is in connection 

 with the positive pole of a battery of thirty pairs, as high as the second 

 phalange, and the negative pole be touched by a metallic rod held in 

 the other hand, also moist, the shock is felt in the finger as high as 

 the second phalange ; if the direction of the current be reversed, it 

 is felt as high as the third phalange. The first shock is also perceiv- 

 ed to be more superficial and attended by a sensation somewhat pain- 

 ful, while the second is deeper, and no sensation is perceived when 



;er is in contact with the water. In the latter case, the shock 

 is both idiopathic and sympathic ; in the former, the current goes in 

 a direction contrary to the branching of the nerves, and instead of 

 producing a shock it gives rise to a sensation. 



If a metallic rod covered with a wet cloth, be taken in each hand 

 and the poles of a battery of thirty or forty pairs be touched, there 

 is felt beside the shocks, every time the circuit is closed, a particu- 

 lar sensation in the palm of the hand, touching the positive pole. 

 With some persons very sensitive to electricity, this sensation is like 

 that which is experienced in the hands or feet after the nerves have 

 been for some time compressed. 



These facts, if more thoroughly examined, may probably lead to 

 some useful results, especially in cases of diease. — Bib. Univ. De- 

 cern. 1829. 



fin 



2. Elastic force of steam. — M. Dllong, in the name of a com- 

 mittee of the Academy of Sciences, made a report on the 30th of 

 November, "of experiments made to determine the elastic force of 

 the vapor of water at high temperatures, by order of the Academy." 

 Dulong and Arago, who had been specially charged with the experi- 

 ments, thought best to measure the tension of steam by the com- 

 pression of atmospheric air. The first thing was to satisfy them- 

 selves of the permanency of the law of Marriotte at high pressures, 

 a permanency which had never been verified. They accomplished 

 this by means of a tube seventy or eight}* feet high, erected in a 

 tower of die old church St. Genevieve. In thirty nine experiments, 

 made upon a mass of air subjected to a pressure from 1 to 27 atmos- 

 pheres, the law of Marriotte was found to prevail without the least 

 appreciable deviation. This first point being established, they were 



