216 Royal Society : — 



the thermometer soon rises to 200°; but beyond this point the vapour 

 is very prone to decomposition, with deposit of metallic lead. 



From this tendency to change, there is some difficulty in obtaining 

 the substance wholly pure from bodies with lower boiling-points. 

 The larger portion came over between 198° to 202°. Its specific 

 gravity was found to be 1*55. 



Analysis led to the formula 



PbC,H,„,orPb(C,H,),. 



It should, however, be noticed that a trifling excess in the per- 

 centage of carbon obtained, showed an increase rather than a decrease 

 in the number of equivalents of ethyle. 



This radical, for which the provisional name of plumbic bis-ethyle 

 is suggested, is a colourless fluid, possessing little or no odour. It 

 is insoluble in water, but perfectly miscible with ether. It burns 

 readily with a beautiful orange-coloured flame, edged with blue, and 

 gives ofi^ fumes of oxide of lead. 



The radical appears to be incapable of forming salts without a 

 partial decomposition. With weak acids there is no perceptible 

 action j but when they are concentrated and gently heated, a gas is 

 giA'cn off', and crystalline salts are produced. 



The chloride is insoluble in water, but soluble in alcohol and in 

 ether, from which last liquid it crystallizes in satiny needles, which are 

 very volatile and provoke sneezing and lachrymation. It burns with 

 the characteristic lead flame, and by long digestion with concentrated 

 hydrochloric acid, is converted into chloride of lead and volatile 

 products. 



The sulphate also appears as a crystalline mass when plumbic-bis- 

 ethyle is gently warmed with a few drops of concentrated sulphuric 

 acid. It is conveniently prepared by agitating the materials in a 

 stoppered bottle, an exit being made from time to time for the gas 

 which is liberated. 



Both these salts require analyses to fix their composition, the 

 details of which the author hopes shortly to be able to communicate. 



The Action of Zinc-ethyle on Chloride of Silver. 



These substances react with some violence, and a black substance 

 sinks in the liquid, which proved to be a mixture of chloride and 

 metallic silver. The zinc-ethyle seems partly to escape decomposition, 

 even when the chloride is in excess and considerable heat is applied. 

 On the addition of water, effervescence sets in, and chloride of zinc 

 is alone found in solution. 



In another experiment dry ether was employed instead of water, 

 under a supposition that a solid compound might be formed, soluble 

 in that menstruum. The only reaction, however, appeared to be 

 that expressed by the equation, 



C, H5 Zn + Ag Cl=Zn CH- Ag-f C, H^. 



A similar negative result was obtained when zinc-ethyle was made to 

 react on protochloride of platinum, Pt CI. The action is violent, 

 mid the platinum is thrown down in the form of platinum-black. 



