518 Prof. W. C. Boherts-Austen on Metals, dc. [Feb. 5, 



can be revealed by the method Prof. Hartley * has given us for detecting 

 the presence of gold in an alloy by volatilising the alloy in a torrent 

 of sparks from an induction coil, and condensing the vapour on mica. 



The union of the aluminium and the gold must, however, be 

 peculiar. Crookesf has shown that when this alloy is used as an 

 electrode in a vacuum tube, the gold is volatilised from the alloy and 

 deposited as a film on the glass, leaving the aluminium behind. 



The purple alloy presents us with the most interesting case yet 

 known of a molecule built up of purely metallic atoms, but we are 

 certain that the atoms are still those of gold and aluminium — that is, 

 the atoms of the united metals remain unchanged. The interest in 

 this substance is deepened if it be remembered that our aim at the 

 present day is the same as that of the alchemists, for we are strivinsj, 

 as they did, to attack and change the chemist's atoms themselves. 

 We seek, as truly as they, to effect the transmutations, which, as 

 Boyle said, would " be none the less real for not being gainful," 

 and employ high temperatures in the hope of simplifying the 

 molecular structure of metals. We no longer consider gold to be 

 the " sum of perfection," but still retain the belief expressed by 

 Geber, eleven hundred years ago, that, " if we would change metals, 

 we must needs use excess of heat." A poet also appears to have 

 felt this, for George Herbert writes in the seventeenth century — 



"I know . . . what the stars conspire, 

 What willing Nature speaks, what forced by fire " ; 



thus comparing the ordinary response of nature to the investigator, 

 with the evidence he elicits from her by heat. 



By fusing gold, and staining it " the purple of the dawn," a new 

 interest has been given to the metal which the alchemists always 

 connected with the sun ; and for further proof that metallic atoms 

 may be changed, we must turn to the sun itself, as to the great 

 metallurgical centre, where " all the elements shall melt with 

 fervent heat." 



♦ Proc. Roy. Soc. vol. xlvi. 1889, p. 88. 

 t Ibid. vol. 1. 1891, p. 88. 



[W. C. P.-A.] 



WEEKLY EVENING MEETING, 



Friday, February 12, 1892. 



Basil Woodd Smith, Esq. F.R.A.S. F.S.A. Vice-President, 



in the Chair. 



G. J. Symons, Esq. F.R.S. Sec. R.M.S. 



Bain, Snow, and Hail. 



[No Abstract.] 



