between Metallic Masses having different Temperatures. 25 



is immediately suggested : Is the property of lead as the cold 

 metal peculiar to it? or does it only require a certain space 

 between any two metals in this scale to produce the effect? 

 For example, lead being placed in the arrangement between 

 tin and antimony, platinum is the third metal above it ; the 

 question is, Would platinum used as the cold metal bear the 

 same relation to gold, the third metal above it, as lead does to 

 platinum ? This is the principle, though of course we are not 

 bound to suppose that the energy is proportional to the num- 

 ber of metals interposed in the list ; since we have already 

 seen that the vibrating property in relation to cold lead is al- 

 most the same in several consecutive metals. The observation 

 stated by Mr. Faraday, forcibly suggests the idea that a certain 

 interval in the scale of metals is alone required to produce the 

 effect ; the lowest metal being necessarily the coolest. 



29. The following are some cases of decided vibrations ob- 

 tained among numerous experiments. Upon cold tin, heated 

 silver, copper, gold and iron vibrate in the order just stated, 

 silver being the most intense. Upon cold iron, silver vibrates 

 decisively : my experiments, therefore, confirm the. statements 

 of Mr. Faraday. With hot copper I have likewise obtained 

 distinct vibrations, though it is not possible at all times to re- 

 peat the experiment in a satisfactory manner. With hot gold. 

 the vibrations were dubious. Upon cold zinc, no hot metal 

 except silver has been observed to vibrate. In this case, how- 

 ever, the effect is decided. I have in no case observed that 

 copper, silver, or gold, have any action when cold upon other 

 metals heated. 



30. It is well worthy of notice, that, from multiplied experi- 

 ments with antimony and bismuth, and at a great range of 

 temperature, I have been led to the conclusion, that among 

 all the metals under trial none have any vibrating energy with 

 antimony and bismuth, whether hotter or colder than these 

 metals, whether used as bars or blocks. There is only a single 

 experiment in my note-book which offers any exception. On 

 one occasion very hot brass was observed to vibrate on cold 

 antimony; on another occasion, however, no such effect was 

 produced. This solitary experiment appears to be one of 

 those anomalies which have frequently exercised my patience, 

 and retarded my progress in this delicate inquiry. 



31. These experiments, it will be observed, aid us in giving 

 a definitive arrangement to the metals in the Table before 

 given, and which, in fact, have been resorted to in order to 

 determine with accuracy the position of metals, of which the 

 vibrating power with regard to lead might be somewhat 

 doubtful. This was particularly the case with some of the 



'J 'hint Scries. Vol. 4. No. 19. Jan. 1834. E 



