408 Scientific Intelligence. 



in neither case did I observe the slightest deflection, which might be 

 anticipated from the known properties of thermo-electric phenomena; 

 nevertheless it appeared to me of use to verify this in the present in- 

 stance. To avoid the effect of a more or less deep immersion of the 

 metallic plates, in consequence of the introduction of the fingers, I 

 partly covered these plates with black wax, so that the uncovered sur- 

 face was always in contact with the solution. 



As regards the fingers, I attempted to immerse them to the same ex- 

 tent in all the experiments, having found that in plunging successively 

 one, two or three, or more fingers, or a single finger to a greater or 

 less depth, the intensity of the deflections varied. This result indeed 

 had been anticipated. I had even had some long kinds of copper thim- 

 bles gilt, so as to regulate the immersion belter. But I abandoned this 

 method of proceeding, because it differed too much from that adopted 

 by M. Du Bois Reymond. 



In experiments made according to M. Du Bois Reymond's process, 

 the alternate contraction of each arm has sometimes afforded deflec- 

 tions in the same, sometimes in the opposiie direction. 



In other experiments, each arm was successively contracted out of 

 the water, and on each contraction the vessels were connected by 

 means of the fingers. In others, large capsules were used, so as to 

 allow more freedom of motion of the hands, and so as to permit the 

 immersion of the closed hands, either contracted or not contracted. 

 The results of these two series of experiments are sometimes favora- 

 ble, sometimes contrary to the assertion of M. Reymond. The neces- 

 sity of multiplying the experiments is very distinctly shown in this case. 

 The results of two or three experiments agree with the results announ- 

 ced by M. Reymond; and then, if they are continued, opposite results 

 are obtained. A singular fact is also remarked in these experiments, 

 viz., that the fingers are influenced much in the same way as metallic 

 conductors; they lose part of their efficacy by repeated immersions. 



I was desirous of reducing the experiment to a greater amount of 

 simplicity. I replaced the galvanometer by a frog which was properly 

 prepared. Several persons, separately or in connection, having strongly 

 contracted one of their arms, in vain endeavored to produce convulsive 

 movements, by connecting the two arms by means of the most sensible 

 parts of the animal. Nevertheless with a very fine copper wire and a 

 plate of zinc, without the use of any liquid, very marked contractions 

 were produced both before and after the experiment. 



I also endeavored in vain to deflect a very delicate astatic magnetic 

 needle, by the union of the two hands, whilst one hand was strongly 

 contracted. Finally, I attached a cylindrical gilt conductor to the back 

 of each hand by silk cord : the contraction of one or the other arm did 

 not perceptibly change the deflection of the needle, which amounted 

 to 10° from the simple contact. The effects of the contact were in- 

 creased in a marked degree by moistening the back of the hand with a 

 few drops of salt water; but the contraction of one or the other arm 

 did not produce deflections alternately in one or the other directions. 



These three experiments appear to me to be under more favorable 

 conditions than those of M. Reymond. The results of them are re- 

 moved from the intervention of the immersion of metallic laminae in 



