292 



SCIENCE- GOSSIP. 



goes on for all eternity — if only the stream of replen- 

 ishing atoms be maintained and the temperature 

 properly adjusted. It is from some such state of 

 harmonious motion here pictured, and made possible 

 by the presence of jarring atoms of nitrogen which 

 by their changealile attractive capacity render the 

 system so unstable, that in all probability the pheno- 

 menon of life arises. 



Before life can arise we probably must have (J) an 

 atom, like carbon, which is capable of Unking 

 together a large number of atoms ; (2) a motion 

 of such an intensity among the atoms as just 

 to overcome the attractive power of the con- 

 trolling carbon atoms, or system of atoms ; (3) a 

 great Constancy in the attractive capacity of the 

 central linking atoms, in order that the gliding away 

 of the various systems may be attained as soon as 

 the proper amount of motion, and consequent pull, 

 is reached. These conditions appear to be satisfied 

 by those under which we live. 



The temperature of men, and of mammals gene- 

 rally, keeps remarkably constant, and the external 

 conditions are such as to allow this constant tempera- 

 ture to be maintained. Indeed, life in its present 

 form can only flourish between very narrow limits of 

 temperature. It is within these limits only that such 

 complex and unstable carbon compounds can exist in 

 a state of continual decomposition — a state which is 

 essential to the maintenance of life. Above this 

 temperature these compounds break down into more 

 stable forms of matter. Below this temperature the 

 continual metathesis ceases. 



Obviously the necessary temperature depends both 

 upon the nature of the central linking element, in 

 our case carbon ; and upon, but to an unknown 

 extent, the external forces, such as gravity, to which 

 matter is subject. 



Looking around among the compounds of carbon, 

 we are struck with the number of its compounds 

 which are liquid or semi-liquid, at ordinary tempera- 

 tures or at the temperature of the blood. This fluidity 

 of the carbon compounds, combined with the great 

 atom-combining power of carbon, is in all probability 

 the reason why, under ordinary conditions, carbon 

 is the central or determining element of the animal 

 organism. At higher temperatures the volatility of 

 the carbon compounds would be so increased as to 

 render impossible the existence of a complex carbon 

 compound in a state of continuous change. While 

 at- very low temperatures the motion among the con- 

 stituent atoms of these carbon compounds would be 

 so reduced that the peculiar and fixed attractive 

 power of the carbon atoms would render any breaking 

 away impossible, and then the compound would be- 

 come stable. In either case life would be impossible. 



The teniperatii7-e of animal life, then, is the tran- 

 sitional or critical tetnperatiire at ■which a large 

 number of unstable carbon compounds are capable 

 of momentary' existence, a higher temperature 

 rendering their existence impossible, while a lower 

 temperature would make the compound stable. 



One must be struck with the large number of im- 

 portant changes which occur among organic carbon 

 compounds between the small range of temperature 

 10° to 90° C, and it is obvious that this fact 

 must have some deep and fundamental connection 

 with the phenomenon of life. 



Conceive now the temperature of the earth and all 

 objects thereon lowered by say 300° C. How would 

 the carbon compounds appear to the eye of man ? 

 They would be hard, and in many cases transparent 

 or translucent solids ; in other cases, opaque. They 

 would, in fact, appear to us as the silicates now are, 

 vast complex bodies having exceedingly high mole- 

 cularwei :hts. Weshouldprobably be entirely ignorant 

 of the inner working of the carbon compounds. We 

 might indeed notice that when (say) acetyl chloride 

 and many organic compounds are heated up to what 

 would appear a red heat, the organic compound is 

 attacked. Such reactions, however, would possess 

 no more significance to the chemist living at that low 

 temperature, than the fact that lead oxide attacks- 

 siliceous matter at high temperatures has for us. 



This property carbon has of acting the role of the 

 fundamental element in the animal organism is then 

 probably a mere function of the temperature, and 

 greatly dependent upon the fluidity of its compounds 

 at this temperature. We are therefore justified in 

 asking whether there is any other element which at 

 some other temperature could play the part at ordinary 

 temperatures like carbon in organic matter? 



Silicon is such an element. 



Silicon, like carbon, possesses a high and constant 

 valency. There is, indeed, a great similarity between 

 the compounds of carbon and silicon. The number 

 of complex double-oxides of silicon is innumerable. 

 True, we cannot effect the synthesis of these 

 compounds and determine their constitution as in 

 the case of the complex carbon compounds ; 

 but in great measure this is an accident of tem- 

 perature rather than anything else. If we could 

 work at a temperature of 700°-l000° C. as easily as at 

 the normal temperatures, there is little doubt that a 

 great flood of light would soon illuminate this portion 

 of our science. We might indeed shortly be able to 

 generate a "Chemistry of the Silicon Compounds."' 

 There is, however, one great distinction between 

 silicon and carbon. Carbon expends its energies in 

 forming a series of hydrides and their derivatives. 

 Silicon equally vigorously spends its energies in pro- 

 ducing double oxides. There probably, indeed, 

 exists for silicon as for carbon a transitional tempera- 

 ture above which very complex compounds would be 

 incapable of existing, while below this temperature 

 the compound would become stable. At the transi- 

 tional temperature complex compounds would be 

 capable of a continual metathesis, and thus give rise 

 to the phenomenon of life ; only in this case all forms 

 of life would have as the determining element not 

 carbon, but silicon. Seeing that in the case of carbon 

 this temperature occurs when many of its compounds 

 are in a semi-fluid condition, or at any rate near their 



