

Chemical Science. 159 



diameter, and one or two inches long. The globules, now extended 

 from one quarter of an inch of the end to the distance of one-fourth or 

 one-third of an inch all round. They were perfectly visible to the 

 naked eye, and of all the colours before-mentioned ; some were so 

 limpid as not to be distinguishable from diamond. In one instance, 

 only was a globule found on the point ; " it would seem as if the 

 melted spheres of plumbago, as soon as formed, rolled out of the 

 current of flame, and congealed on the contiguous parts. The exca- 

 vation on the copper side, and accumulation on the zinc side, were 

 constant. The result too obtained when the charcoal was on the 

 copper, and the plumbago on the zinc side was constant. The char- 

 coal was rapidly volatilized, a cavity formed, and the matter removed 

 accumulated upon the plumbago point, forming a protuberance easily 

 distinguished from the plumbago ; and when seen by the microscope 

 presenting an aggregation of spheres with every mark of perfect 

 fusion, and with a perfect metallic lustre." 



In another experiment the spheres were very numerous and white 

 like calcedony, " they appeared to me to be formed by the conden- 

 sation of a white vapour, which in all the experiments where an 

 active power was employed, I had observed to be exhaled between 

 the poles, and partly to pass from the copper to the zinc pole, 

 and partly to rise vertically in an abundant fume, like that of the 

 oxide proceeding from the combustion of various metals ;" this fume 

 is easily condensed on glass held over it, rendering it opaque from a 

 white lining; there was a distinct and peculiar odour in the fume, 

 but the condensed matter was tasteless, did not effervesce with acids 

 or effect test papers; it was concluded, therefore, not to be alkali : " it 

 seems possible that it is white volatilized carbon, giving origin by its 

 condensation in a state of greater or less purity to the grey, white, 

 and, perhaps, to the limpid globules." 



Some of the coloured globules were collected together, they rolled 

 about like shot ; they were rubbed in the hand to free them from 

 plumbago, and then placed upon a fragment of Wedgwood-ware 

 floated in a dish of mercury, and a small jar of very pure oxygen 

 gas, previously washed and tested by soda and lime-water slid over 

 them. The globules were heated by a powerful lens ; for half an 

 hour they did not melt, disappear, or alter their form, but carbonic 

 acid was afterwards found in the gas on examination with lime- 

 water. " In a long-continued experiment, it is presumable that 

 they would be eventually dissipated, leaving only a residuum of iron. 

 That they contain iron is manifest from their being attracted by the 

 magnet, and the colour is evidently owing to the metal." " It would 

 be interesting to know whether the limpid globules are also magnetic ; 

 but this trial I have not yet made." 



In some cases the white fume collected in considerable quantities 

 on the charcoal, and looked like a frit of white enamel, or a little 

 like pumice-stone. " Had we not been encouraged by the remark- 



