166 Miscellaneous Intelligence. 



Many causes, such as pressure, rolling, annealing*, &c, may 

 more or less alter the distribution of the elasticity of metals, but 

 none of them appear to be of such a nature as to bring them to a 

 homogeneous state. Thus, circular plates of lead, copper, tin, and 

 brass, diminished to one-fourth of their first thickness by hammer- 

 ing, preserved nearly the same properties as they had immediately 

 after fusion : their nodal systems were only a little changed in ap- 

 pearance, but the sounds accompanying them were at the same 

 distance from each other as before. 



Rolling produced similar effects, except that the crystalline sys- 

 tems were considerably extended in two directions parallel to each 

 other, so that it does occasionally happen that plates of large size 

 may present a structure approaching to regularity. This occurred 

 with a plate of zinc, from which several discs were taken, so similar 

 in properties, that the plate might be considered as regularly crys- 

 tallized. A close examination of this plate in various directions 

 gave such differences of elasticity as to lead to the conclusion, that 

 the differences of resistance to flexure in different directions of the 

 same mass of metal may be much greater than occurs even in some 

 woods — as, for instance, the oak, beech, &c, and yet, as has been 

 demonstrated in a former paper, :the extreme elasticities in the beech 

 are to each other as 1 is to 16. 



The influence of annealing appears to be very feeble, or even 

 nothing, upon metals which have not been compressed ; for discs of 

 copper, which had been exposed for hours to a temperature near the 

 point of fusion, gave the same sounds as before. But when the 

 metals have first been pressed, then annealing slightly alters their 

 tone and the disposition of the nodal lines. 



The phenomena observed in the metals were found to occur also 

 with glass, sulphur, common resin, copal, amber, plaster, slate, &c. ; 

 but the interval between the two sounds belonging to circular plates 

 of these substances is always very small, rarely surpassing a major 

 semitone: the two modes of division also shewn by the nodal lines, 

 although they affect a fixed position, are so near to each other as 

 mostly to give a rectangular cross. It is to be presumed, indeed, 

 that a heterogeneous structure will be discovered in almost every solid 

 substance, except perhaps those which are deposits of pulverulent 

 matter, as chalk, for instance, which appears to approach very 

 closely to homogeneity. Amongst all the bodies examined by M. 

 Savart one only was found, namely, sealing-wax, in which the 

 right-angled cross of nodal lines could be produced indifferently in 

 any direction ; but this substance, being a simple mixture of gum 

 lac, turpentine, and cinnabar, we may imagine how the latter pul- 

 verulent body may prevent the particles of resin from arranging 

 themselves regularly. 



M. Savart concludes his memoir by an observation, apparently 

 applicable to all bodies which crystallize irregularly, namely, that 

 immediately after they have become solid, they vibrate sonorously 

 with much greater difficulty than they do a few hours or days, or 



