442 Prof. FORBES on the Vibrations which take place 



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 tem- 

 perature, I have been led to the conclusion, that among all the 

 metals under trial none have any vibrating energy with anti- 

 mony and bismuth, whether hotter or colder than these metals, 

 whether used as bars or blocks. There is only a single experi- 

 ment in my note-book which offers any exception. On one oc- 

 casion very hot brass was observed to vibrate on COLD ANTI- 

 MONY ; on another occasion, however, no such effect was pro- 

 duced. This solitary experiment appears to be one of those 

 anomalies which have frequently exercised my patience, and re- 

 tarded my progress in this delicate inquiry. 



81. 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 metals highest on the 

 scale : An example will illustrate the mode of operation. 



32. 30th July 1831. Experiments made with masses of sil- 

 ver, copper, and gold, placed in a vice, and heated with a spirit- 

 lamp until a globule of water evaporated in violent ebullition 

 from its surface. The cold metals were employed as bars. 



HOT SILVER. 



Cold Lead. Vibrates perfectly well. 



Tin. Apparently as well as Lead. 



Zinc. Vibrates very well. 



Iron. Vibrates distinctly; but apparently less than Zinc. 



Brass. Not decisively. 



Copper. Not at all. 



