38 1 Royal Society .— 



The solubility of these salts in aqueous potash has been rather 

 variously stated by Lowig and Fraukland, and also their characters 

 as odorous and hiodorous. The truth is, that unless the salts of 

 stanethyle are formed from the oxide, they are almost always con- 

 taminated with the above-mentioned oily chloride, the oxide of which 

 is soluble in potash. As oxide of stanethyle is not affected by al- 

 kaline solutions, these two bodies may be separated without diffi- 

 culty. 



The soluble oxide may be recovered from the alkaline solutions by 

 distillation. It passes over, together with aqueous vapour, in the 

 form of an exceedinglj- caustic and pungent oil, which blues litmus, 

 and has all the characters of a powerful base. Water dissolves it in 

 moderate quantities, but precipitates it again on the addition of com- 

 mon salt. When deprived of watei', the oily base solidifies into a 

 crystalline mass. 



This oxide forms definite salts with acids, all more or less pun- 

 gent. With hydrochloric and hydiiodic acids, uncrystallizable bodies, 

 insoluble in water, are produced, but with sulphuric acid it forms 

 fine, colourless crystals, which by analysis gave the formula 

 Su, C,, H,, SO, or Sn, (C, H,), SO,. 



For this compound I propose (he name of sulphate of distannic 

 triethyle. It has, in a remarkable degree, the unusual ])roperty of 

 being more soluble in cold than in hot water. A cold saturated 

 solution becomes semi-solid by raising the temperature somewhat 

 below ebullition. 



A consideration of the elements of the above formula fm-nished 

 an idea of these bodies being either double salts, compounded of 

 one equivalent of stannic diethyle with one equivalent of any salt, 

 Sn C, H, X, or else a combination of three equivalents of stannic di- 

 ethyle, with one equivalent of an inorganic salt Su X.^, resulting in two 

 molecules of the sesqui-ethylated salt. Thus 



3 Sn (C, H,), + Sn Cl=2 Sn, (C, H,), CI. 



Experiment proves that the former bodies mix, but do not combine 

 chemically, at any moderate heat. The latter bodies, on the other 

 hand, exhibit strong chemical action, and disengage great heat during 

 combination. 



Bichloride of tin forms an oily body with stannic diethyle, chiefly 

 composed of chloride of distannic triethyle, which by treatment with 

 potash may be made to furnish the corresponding salts without 

 difficulty. 



Iodide of distannic triethyle may often be found amongst the j)ro- 

 ducts of the action of tin on iodide of ethyle. It is very probably 

 identical with the oil noticed by Riche and Cahours, and described 

 by them as possessing the pungent odour of oil of mustard. 



These salts also must be considered to be identical with those 

 described by Lowig under the somewhat inappropriate name of 

 "methylo-stanethyles." The present name is suggested as more in 

 accordance with their true constitution. They finally pass, by the 

 action of zincethyle, into the radical stannic diethyle. 



