1819.] Scientific Intelligence. 229 



and soon ceases to be observable. The same results take place 

 in the apparent motions of sonorous strings. This effect is 

 comparable to that of the diffusion of heat in solid matter. 



" We now terminate the account of our researches on the 

 motion of elastic surfaces. They furnish new proofs of the 

 extent of that mathematical analysis whose principal object is the 

 interpretation of natural phenomena. This science expresses, in 

 simple forms, the most complicated natural effects ; it shows us 

 those which subsist far from us at immense distances, and those 

 which will only be accomplished in future times, or which have 

 preceded us for ages ; it determines the general and simple laws 

 which regulate all the motions of heat, or the harmonious oscil- 

 lations of sonorous bodies, and discloses to us secret analogies 

 between phenomena — analogies which apparently must for ever 

 have escaped our experience. This science is, in a manner, 

 destined to aid our instruments and our senses ; it brings the 

 study of nature to a limited number of primordial observations, 

 which have for their object the measuring of the dimensions or 

 the specific qualities of bodies." 



{To be continued.) 



Article XL 



SCIENTIFIC INTELLIGENCE, AND NOTICES OF SUBJECT* 

 CONNECTED WITH SCIENCE. 



I. Volatility of Bismuth. 



M. Chaudet has made a set of experiments upon the fixity of 

 "bismuth, from which it appears, that this metal, though covered 

 with charcoal, is completely volatilized if it be kept for a suffi- 

 cient time at a temperature of about 30° Wedgewood. — (Ann. 

 de Chim. et de Phys. ix. 397.) 



II. On the Alloy of Platinum and Lead. By Dr. Clarke. 



(To Dr. Thomson.) 

 DEAR SIR, Elsenham Hall, near Bishop's Storl/ord, Essex, July 10, 1819. 



One of your correspondents mentions the astonishing affinity 

 of platinum and lead at no very exalted temperature before the 

 common blow-pipe. I think this deserves more of your notice 

 than perhaps you have hitherto shown it. The experiment with 

 these metals is one of the most striking you can conceive ; but 

 you must make it cautiously, or you will be liable to have your 

 hands very much burned. If you take two pieces cf lead-foil 

 and platinum-foil of equal dimensions, and roll them together, 

 and place the roll upon charcoal, and direct the flame of a 

 candle cautiously towards the edges of the roll, at about a red 



