258 CrystaUizution of Metals by Electricity. 



leaves indeed being described as recurved at the point, which might 

 perhaps refer to them in a dry state. Bridel also admits 8. mollus- 

 cum into the Bryol. Univ., but he only copied the description of 

 Bruch (1825) -without having seen a specimen. I have no hesita- 

 tion therefore in adopting the name first given to the species. 



\I. — Crydallization of Metals hy Electricity. 



By Philip Braham. 



Plate XX. 



The accompanying illustration represents the result of a series of 

 experiments, and shows their most distinctive appearance as seen 

 with a 2-inch objective. 



Gold and copper are nodular in their formation, copper having 

 the larger and more definite spherules. 



Silver is peculiarly fine, and leafy, and has its main line of 

 crystallization distinctly marked. 



Tin may be considered the most beautiful object ; its invariably 

 rectangular crystal, straight direction, and rectangular deviation, 

 are exceedingly characteristic. 



Lead may be likened to silver enlarged ; but the breadth and 

 taper of the leaves, and its want of centre line, are very distinctive. 



Zinc grows feathery, with a crystalline, fungoid aj^pearance. 



There are apparently other forms, which make their appear- 

 ance with the same metals ; but on careful investigation they • are 

 found to be only modifications of those illustrated. 



It is worthy of notice tbat the two yellow-coloured metals have 

 decidedly sj^herical formation, and that gold leaf transmits a blue 

 light, and the salts of copper are beautifully blue. The size of the 

 crystals depends on the regulation of the battery ; the more rapidly 

 they are formed the smaller they are. 



I have tried the experiments away from the microscope, and 

 have been generally disappointed with the result ; the difficulty of 

 manipulating aAvay from it may be easily conceived by considering 

 the solution to be a resistance to the electricity, and as the metallic 

 crystals form that resistance is diminished, and a rush of crystals 

 spoils the experiments. 



I have succeeded in obtaining crystalline appearances from 

 platinum, palladium, iron, bismuth, and antimony, but not of a 

 very definite character. 



The delicacy of some of the crystals will not allow of their 

 being kept, and the beauty of their apj^earance is lost by drying. 

 The more oxidable metals tarnish immediately, so that no ade- 



