Royal Society. 61 



formula of stanethylium is C4 H5 Sn ; that of the oxide C4 H5 SnO, 

 and that of the bromide C4 H3 Sn Br. Stanethylium therefore per- 

 fectly resembles cacodyle in its reactions, combining directly with 

 the electro-negative elements, and regenerating the compounds from 

 which it has been derived. 



Stanmethylium and stanamylium are formed when the iodides of 

 raethyle and amyle respectively are exposed to the action of light in 

 contact with tin ; their salts are isomorphous with those of stanethy- 

 lium, but they have not yet been completely investigated. 



Zincmethylium. — This radical is formed in an uncombined state 

 when iodide of methyle and zinc are exposed to a temperature of 

 about 150° C. in a sealed tube ; the zinc gradually dissolves with 

 an evolution of gas, whilst a mass of white crystals and a colourless 

 mobile liquid refracting light strongly, occupy, after a few hours, 

 the place of the original materials. In this reaction two distinct 

 decompositions take place, viz. the decomposition of iodide of methyle 

 by zinc with the production of iodide of zinc and liquid zincmethy- 

 lium, and the decomposition of iodide of methyle by zinc with the 

 formation of iodide of zinc and the gaseous radical methyle. The 

 zincmethylium was obtained pure by distillation in an atmosphere 

 of dry hydrogen. Its formula is Cg H3 Zn, and it possesses the fol- 

 lowing properties. It is a colourless, transparent and very mobile 

 liquid, possessing a peculiar penetrating and insupportable odour, 

 and boiling at a low temperature. Zincmethylium combines directly 

 with oxygen, chlorine, iodine, &c., forming somewhat unstable com- 

 pounds. Its affinity for oxygen is even more intense than that of 

 potassium ; in contact with atmospheric air it instantaneously ig- 

 nites, burning with a beautiful greenish blue flame, and forming 

 white clouds of oxide of zinc ; in contact with pure oxygen it burns 

 with explosion, and the presence of a small quantity of its vapour in 

 combustible gases gives them the property of spontaneous inflamma- 

 bility in oxygen. Thrown into water, zincmethylium decomposes 

 that liquid with the evolution of heat and light ; when this action is 

 moderated, the sole products of the decomposition are oxide of zinc 

 and hydride of methyle. 



The extraordinary affinity of zincmethylium for oxygen, its pecu- 

 liar composition, and the facility with which it can be procured, can- 

 not fail to cause its employment for a great variety of transforma- 

 tions in organic compounds ; by its agency there is every probability 

 that oxygen, chlorine, &c. can be replaced atom for atom by methyle, 

 and thus entirely new series of organic compounds will be produced, 

 and clearer views of the rational constitution of others be obtained. 



The gaseous methyle formed simultaneously with zincmethylium 

 is identical in composition and properties with the methyle derived 

 from the electrolysis of acetic acid ; it was mixed, however, with 

 hydride of methyle generated by the decomposition of accompanying 

 zincmethylium vapour by the water over which the gas was col- 

 lected. 



Zincethylium and zincamylium are homologous bodies formed by 

 similar processes ; their investigation is not yet completed. 



Hydrargyromethylium. — The author has only yet studied the iodide 



