342 PRINCIPLES OF CHEMISTRY 



to the present time there are no grounds for determining the degree 

 of polymerism cf the charcoal, graphite, or diamond molecules, and it 

 can only be supposed that they contain C,, where ?t is a large quantity. 

 Therefore charcoal and those complex noii- volatile organic substances 

 which represent the gradual transitions to charcoal 19 and which form 

 the principal masses of the organisms, contain a store or accumulation 

 of internal power in the form of the energy binding the atoms into 

 complex molecules. When charcoal or complex compounds of carbon 

 burn, the energy of the carbon and oxygen is turned into heat, and 

 this fact is taken advantage of at every turn for the generation of heat 

 from fuel. 20 



No other two elements are capable of combining together in 

 such variety as carbon and hydrogen. The hydrocarbons of the 

 C,,H 2m series in many cases widely differ from each other, although 

 they have some properties in common. All hydrocarbons, whether 

 gaseous, liquid, or solid, are combustible substances sparingly soluble 

 or insoluble in water. The liquefied gaseous hydrocarbons, also those 

 which are liquid at ordinary temperatures, and those solid hydrocarbons 

 which have been liquefied by fusion, have the appearance and property 

 of oily liquids, more or less viscid or fluid. 21 The solid hydrocarbons 



19 The hydrocarbons, poor in hydrogen (far from the limit) and containing many 

 atoms of carbon, like chrysene and carbopetrocene, itc., C,,Ho(,,_ W ) are solids, and less 

 fusible as n and in increase. They present a marked approach to the properties of the 

 diamond. And in proportion to the diminution of the water in the carbohydrates 

 C/jHoTOOwi for example, in the liumic compounds iXote ~>) the transition of complex 

 organic substances to charcoal is very evident. That residue resembling charcoal and 

 graphite whk;h is obtained by the separation (by means of copper sulphate and sodium 

 chloride) of iron from white cast-iron containing carbon, chemically combined with the 

 iron, also seems, especially after the researches of G. A. Zaboudsky, to be a complex 

 substance containing C^H^O^. The endeavours which have been directed towards 

 determining the measure of complexity of the molecules of charcoal, graphite, and the 

 diamond will probably at some period lead to the solution of this problem, and will most 

 likely prove that the various forms of charcoal, graphite, and the diamond contain mole- 

 cules of different and very considerable complexity. The constancy of the grouping of 

 benzene, C C H 6 , and the wide diffusion and facility of formation of the carbohydrates. 

 containing C 6 (for example, cellulose, C C H 10 O 3 , glucose, C H 12 O<3),give reason for thinking 

 that the group C 6 is the first and simplest of those possible to free carbon, and it may 

 be hoped that some time or other it may be possible to get charcoal in this group. 1 Vr- 

 haps in the diamond there may be found such a relation between the atoms as in tin- 

 benzene group, and in charcoal such as in the carbohydrates. 



20 When charcoal burns, the complex molecule C,, is resolved into the simple mole- 

 cules ?iCO.>, and therefore part of the heat probably no small amount is expended in 

 the destruction of the complex molecule C tt . Perhaps by burning the most complex 

 substances, which are the poorest as regards hydrogen, it maybe possible to form an 

 idea of the work required to split up C ;i into separate atoms. 



21 The viscosity, or the degree of mobility, of liquids is determined by their internal 

 friction. It is estimated by passing the liquids through narrow [capillary) tubes, the 

 mobile liquids passing through with greater facility and speed than the. viscid ones. The 



