194 ANNUAL OF SCIENTIFIC DISCOVERT. 



by Gamlin, and afterwards by Odling, from a consideration of the 

 vapor-density of certain silicon compounds. Hitherto, however, 

 conclusive proofs, based on purely chemical considerations, have 

 been wanting, and many of the authorities on chemistry have 

 adhered to the old formula. They say : 



" Our research was at first undertaken with a view to proving 

 that the chemical properties of silicates can only be explained by 

 adopting the new formula, and we have succeeded in obtaining 

 bodies whose existence and mode of formation it is impossible to 

 account for by any other theory. Such are the chlorhydrides and 

 acetines derived from normal silicic ether, Si(C 2 H 5 O) 4 , and at 

 first we only studied the compounds which belong to the same 

 type as the normal silicic ether ; but the research led us further 

 than we anticipated, and resulted in the discovery of the more 

 complicated disilicic ethers, already described, whose structure 

 throws some light on the rational formulae of mineral silicates, 

 and also of a remarkable class of bodies, in which the alcoholic 

 radicals, ethyl, C 2 H 5 , and methyl, CH 3 , are combined directly 

 with the silicon, and not, as in the ethers, through the medium of 

 oxygen. The present paper is devoted to the description of the 

 latter bodies. 



" The study of the compounds of silicon with alcoholic radi- 

 cals, fortifies the conclusions already arrived at ; it demonstrates 

 the tetratomicity of silicon, and places it in the same group with 

 titanium and carbon ; and it leads, besides, to the discovery of a 

 property of silicon, which allies that element with carbon far more 

 closely than the equality of their atomicity and the similarities 

 hitherto observed in the structure of their compounds. In fact, 

 silicon has been found to possess the property of combining 

 directly with carbon, or rather with hydrocarbons ; and the 

 resulting compounds are, in every respect, similar to simple 

 hydrocarbons, susceptible like them of substitution of chlorine 

 and bromine for hydrogen, and of acting as radicals in alcohols 

 and ethers; consequently, silicon may take the place of carbon in 

 a hydrocarbon, without modifying, essentially, its properties. It 

 is easy to appreciate the importance of this result. Carbon is 

 characterized by the property of combining with itself to build up 

 groups of atoms, which have been compared to chains or nuclei, 

 about which the atoms of hydrogen, oxygen, nitrogen, etc., found 

 in organic bodies, group themselves, and it is especially this 

 propert} 7 of carbon which fits it to play the part of the element 

 essential to the structure of organic compounds. 



" It has been supposed that carbon alone had the property of 

 combining with itself to form the nuclei of organic compounds, 

 but it now appears that silicon shares with it this quality, and we 

 are led to the opinion, that no element is unique in its properties, 

 but that each has its near relatives among the others, as was indi- 

 cated by Dumas, in dividing the elements into natural families, 

 and as every new discovery daily tends to prove. It is remarka- 

 ble, also, that analogies of this kind, which are independent in 

 their nature of the atomicities of the elements, should occur espe- 

 cially between elements having the same atomicity, and the fact 



