THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



SUPPLEMENT to VOL. XX. THIRD SERIES. 



LXXVIII. On a He-arrangement of the Molecules of a Body 

 after Solidification. By Robert Warington, Esq.* 



TLTAVING occasion lately to prepare some alloys of lead 

 -■--*• for the purpose of lecture illustration, I was much sur- 

 prised at an alteration taking place in the arrangement of the 

 particles of one of these alloys, as shown by the appearance 

 of the surfaces of fracture after the metal had assumed the 

 solid form. The alloy experimented on was that known as 

 Newton's fusible metal, composed of 8 parts of bismuth, 5 of 

 lead, and 3 of tin. On pouring this alloy in the melted state 

 on a marble slab, and breaking it as soon as solid, and when 

 it may be readily handled, the exposed surfaces were found 

 to exhibit a bright, smooth, or conchoidal metallic appear- 

 ance, of a tin-white lustre ; and the act of disjunction at one part 

 will, frequently, cause the whole to fly into a number of frag- 

 ments analogous to the breaking a piece of unannealed glass. 



The metal after this becomes so hot as to burn the fingers 

 if taken up, and when this evolution of heat has ceased the 

 alloy will be found to have entirely altered its characters, 

 having lost its extreme brittleness, requiring to be bent to and 

 fro several times before it will break, and jjresenting on frac- 

 ture a fine granular or crystalline surface of a dark colour and 

 dull earthy aspect. Similar phaanomena accompany the cast- 

 ing of the fusible alloy of V. Rose, composed of 2 parts of 

 bismuth, 1 of lead, and 1 of tin. 



The fact of the evolution of heat from the alloy of Newton, 

 and its cause, are thus noticed by Berzelius in his Traite de 

 Chimie. " If this alloy is plunged into cold water and quickly 

 withdrawn and taken in the hand, it becomes sufficiently liot 

 after a few moments to burn the fingers. The cause of this 

 phaenomenon is, that during the solidification and crystalliza- 

 tion of the i7itcrnal jiarts the latent heat of these is set free and 



• Communicated by flic Chemical Society; having been read January 4. 

 Phil. Mag. S. 3. Vol. 20. No. 1 34-. Snppl. July 1842. 2 O 



