Mr. A. Trevelyan on the Vibration of heated Metals. 331 



" 3rd, The vibrations of the cups above a platina coin were 

 very slow, and did not commence until after the lead had be- 

 come solid : they soon ceased ; — as if connected with the bad 

 conducting power of platina? 



" 4th, The solidifying of the melted metals in the cup, and 

 their crystallization when made to solidify during their vibra- 

 tions, offered several singular phaenomena, particularly with 

 bismuth, lead and tin. As far as trials have yet gone, the cry- 

 stallizing property seemed to be more conspicuous when so- 

 lidifying during the vibrations, than when the same quantities 

 of metals were not vibrating. 



" These observations, like those of your brother, seem to 

 connect this subject closely with the arcana of cohesion. On 

 seeing the copy of your brother's paper, which you were so 

 good as to send me, on the 19th of April, I was naturally much 

 interested in the perusal, and cannot but think his theory 

 the true one. An extensive field seems to be opened for ex- 

 amining the passage of heat through metallic bodies, in con- 

 nexion with the structure of their atoms in cohesion. I could 

 wish much that he or you would repeat some of the above ex- 

 periments. I do not know when I shall find time to resume 

 them. I found indeed, soon after beginning, that I could not 

 advance without one of the small metallic Breguet's thermo- 

 meters, with which the temperature of the ingots might be 

 approximated to. I omitted to mention that the cups them- 

 selves will vibrate, if heated above a gas flame; but the other 

 mode of pouring from a ladle some melted metal is more con- 

 venient, and increases the range of the phenomena ; or hot 

 mercury may be poured in, but the fumes are disagreeable. 



" P.S. If you try any of the experiments, it will give me 

 great pleasure to hear of your success. I have tried them so 

 very often that I am quite sure you will not lose your trouble." 



At one of the meetings of the Royal Society of Edinburgh 

 this spring, Professor Forbes, of the Edinburgh University, 

 read an able paper, and one that showed great research, on 

 the vibration of metals ; he also produced tables showing the 

 difference of metals in the conduction of heat and electricity, 

 and for showing the vibrations : there was great similarity in 

 the position of the different metals in the three columns of the 

 table, showing the difference of power in producing the three 

 various effects*. — In the Literary Gazette for May 17, 1831, 

 Mr. Faraday is mentioned to have shown the experiment of 

 a curved silver plate vibrating and sounding when placed on 

 cold iron, and to have stated that this effect had long been 

 known to working silversmiths. 



* An abstract of Prof. Forbes's paper will be found in our last Number, 

 p. 303.— Edit. 



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