345 



The ordinary reactions of zinc-ethyl may be looked upon as illus- 

 trating this proposition, and can be written so as to exhibit a double 

 displacement. 



Zn, <H 5 + lf=ZnI + C 4 H 5 I 



+ _ +_ + 1 +~^ 

 also ZnC 4 H. + OO= ZnO + C 4 H 5 O 



Inspection will show in all these cases, that an electro-positive 

 radical displaces a less electro-positive radical ; and an electro-nega- 

 tive radical displaces a less electro-negative one. 



In accordance with the theory would be the displacement in 

 sodium-ethyl of the ethyl by mercury, or by copper, &c., platinum, 



&c. 



Na, C 4 H 5 , Cn_NaCn , C 4 H 5 

 Na CH + Cn 



Also a like displacement by arsenic or by nitrogen would be ac- 

 cording to theory. 



Pushing the hypothesis to its furthest limits, I should say that 

 sodium-ethyl is only in equilibrium with bodies whose respective 

 electrical sides lie either both of them within, or both of them with- 

 out the space lying between the electro-positive sodium and the 

 electro-negative ethyl. 



XXIII. "Note on Sodium-ethyl and Potassium-ethyl. " By 

 EDWARD FRANKLAND, Ph.D., F.R.S. Received June 17, 

 1858. 



The recent interesting discovery of sodium-ethyl and potassium- 

 ethyl by Mr. Wanklyn, led me to investigate the cause of the non- 

 formation of these bodies by reactions analogous to those success- 

 fully used for the production of zinc-ethyl and similar organo-metallic 

 compounds. In my earlier experiments upon the isolation of the 

 organic radicals, I studied the action of potassium and sodium upon 

 iodide of ethyl, and found that the latter compound was readily de- 

 composed by either of the metals at a temperature of from 100 to 

 130 C. The separated ethyl was, however, transformed almost com- 

 pletely into hydride of ethyl and defiant gas, whilst not a trace of 

 potassium-ethyl or sodium-ethyl was produced. Mr. Wanklyn has 



