106 M. Savart's Researches on the structure of Metals, 



divide it into several smaller plates also circular, we shall find 

 that these last differ more or less from one another in their 

 sounds and mode of division, and that the nodal lines of the 

 one are rarely parallel to those of the other. 



These and many other facts show distinctly that the metals 

 do not possess a homogeneous structure, but only that they 

 are not regularly crystallized. We have, therefore, only 

 one supposition left, viz. that they possess a semi-regular 

 structure, as if, at the moment of solidification, there were 

 formed in their interior several distinct crystals of a consider- 

 able size, but whose homologous faces were not turned towards 

 the same points of space. In this view the metals would re- 

 semble certain grouped crystals, each of which, considered in- 

 dividually, presents a regular structure, whilst the entire mass 

 is quite confused. 



This view of the matter is supported by several circum- 

 stances which accompany the solidification of metals. If we ex- 

 amine, for example, the surface of amass of lead about to become 

 solid, we shall perceive in some parts small rectilineal grooves, 

 which are sometimes several centimetres long, which have 

 no fixed direction, but which are crossed by a great number of 

 other grooves of the same kind but much shorter, so that the 

 whole surface of the metal seems to be entirely covered with 

 this singular net- work, which evidently indicates a sort of re- 

 gularity in the arrangement of the subjacent parts. If we ope- 

 rate, indeed, with a mass of lead of from twelve to fifteen 

 kilogrammes, and if at the instant when the solid crust is about 

 five or six millimetres (l-4th or l-5th of an inch) thick, we 

 pierce it with a red hot iron, and invert the vessel suddenly, so 

 as to discharge the part of the lead that is still fluid, the inner 

 face of the solid crust will exhibit a number of small octaedral 

 crystals arranged in parallel lines, and crossing one another at 

 right angles, which form a great number of distinct systems, 

 corresponding in position to the small grooves on the opposite 

 surface of the crust. 



Examined with the microscope the small crystals which 

 compose each of these systems, appear to be grouped round 

 three lines at right angles to each other, and they are arranged 

 so that their axes are parallel to each other ; and hence, they 



