104 M. Savarfs Researches on the structure of Metals 



Huel Vor, 



Average duty of rotatory engines, 17.8 millions. 



* 



Watt's double engines. 

 '\ Trevithick's high pressure combined with Watt's single. 



Art. XI. — Researches on the structure of Metals, as indi- 

 cated by their Acoustic properties.* By M. Felix Savart. 



Hitherto melted metals have been regarded as the solid 

 substances which approached most to the condition of homo- 

 geneity. They have been regarded as assemblages of an infi- 

 nite number of small crystals united together without order, 

 and as it were by chance, and it was never even conjectured 

 that in any mass of metal there could be differences of elasti- 

 city and cohesion as great, and perhaps greater, than those 

 which are observed in a fibrous body like wood. 



Experience nevertheless shows, that circular plates of metal, 

 of equal thickness, melted in moulds, or cut in great masses, 

 or taken in thin plates, always comport themselves as if they 

 had belonged to a fibrous body, or to one regularly crystal- 

 lized. Thus, if we seek to make them produce the mode of 

 division which consists of two lines, crossing each other at 

 right angles, we shall soon discover that their intimate struc- 

 ture is not the same in all directions ; for this mode of divi- 

 sion cannot establish itself in two determinate positions, and 

 almost always under the form of hyperbolic curves, which are 

 accompanied with sounds more or less remote from each other, 

 sometimes by a quantity almost imperceptible, and sometimes 

 by a third, a fourth, and even a fifth. Plates of gold, silver, 

 copper, zinc, cast-iron, forged or laminated iron, tin, lead, bis- 

 muth, steel, antimony, and a great number of alloys of these 

 different substances, such as brass, bell-metal, &c. appeared to 



• Translated and slightly abridged from the Annales de Chimie, May 1829. 



