Litelligence and Miscellmiecnis Articles. 145 



the metal pass into the receiver. If the mercury distilled at the com- 

 mencement of the operation be kept separate from that obtained at 

 the end of it, it is easily proved that these two portions are of un- 

 equal volatilit)'. 



Fifty kilogrammes of mercury were distilled, and the first and last 

 kilogramme distilled were kept separate ; both of them were re- 

 distilled and then submitted to the following experiment : four small 

 and similar retorts were selected, each of which when half-filled was 

 capable of holding 100 grammes of mercury. Each of the retorts 

 charged with 100 grammes of the metal was immersed into an alloy- 

 bath in fusion ; and the heat was raised till the mercury in all of 

 them boiled. The mercury distilled condensed in the neck, and was 

 collected and weighed. The four retorts did not yield equal quan- 

 tities ; but on putting aside those which differed the most, it was 

 easy to select two, which, subjected to the above proof, furnished 

 nearly an equal quantity of mercury. Thus in three parallel opera- 

 tions with these two retorts distinguished by the letters A and B — 



In the same time, in the same bath. 

 Retort A. First operation. Mercury distilled 48-5 grammes. 



Retort B. 47-5 



Retort A. Second operation. .... 69'0 



Retort B. .... .... 63-0 



Retort A. Third operation. .... 66-0 



Retort B. .... .... 640 



It is to be remarked that in these three operations the retort A. 

 always yielded a little more than the retort B. This circumstance 

 was attended to in the experiments which follow. 



The following are the diflferences obtained by submitting to com- 

 parative trial in the alloy-bath, mercury taken from the first and last 

 kilogramme obtained from the distillation of 50 kilogrammes of the 

 metal. 



The retort A., which yielded the most, received the mercury col- 

 lected at the close of the distillation ; the retort B. that obtained at 

 the commencement. 



Mercury distilled during the same time in the same bath. 

 Retort A. First operation. Containing 100 grms. of metal 19'0 grms. 

 Retort B. .... .... .... 49-0 .. 



Retort A. Second operation. .... .... 15'7 .. 



Retort B. •.••.-. ^^'^ •■ 



Care must be taken, in these comparative distillations, to mode- 

 rate the temperature of the alloy-bath as soon as the mercury begins 

 to spot the dome of the retort. 



Mercury thus affected in a marked manner in its mode of distilla- 

 tion would appear to possess some difference in its degree of purity ; 

 but the author attemj)tcd in vain to discover any difference by re- 

 agents ; the mercury of the first and last kilogramme was similarly 

 affected in all the examinations to which it was submitted. 



It then occurred to the author to try whether the addition of any 

 foreign metal, in (juantlty so small as to escape analysis, could affect 

 tlic volatility of the mercury. The results were of considerable in- 



