1889.] on an attempt to ajpphj to Chemistrij, &c. 517 



Bunsen have long been seeking, and Berth elot is investigating them 

 at this moment. It is probable, however, that the reaction will stop 

 at the last compoimcl, because we find that, in a number of cases, the 

 addition of 4 atoms of oxygen seems to form a limit. Thus, OsO*, 

 KC10^ KMuO*, K-SO^ Na^^PO^ and such like, represent the highest 

 grades of oxidation.* 



As for the last 40 years, from the times of Berzelius, Dumas, 

 Liebig, Gerhardt, Williamson, Frankland, Kolbe, Kekule, and 

 Butlerow, most theoretical generalisations have centred round organic 

 or carbon comjDOunds, so we will, for the sake of brevity, leave out 

 the discussion of ammonia derivatives, notwithstanding their sim- 

 plicity in respect to the doctrine of substitutions ; w^e will dwell more 

 especially on its application to carbon compounds, starting from 

 methane, CH*, as the simplest of the hydrocarbons, containing in its 

 molecule one atom of carbon. According to the principles enume- 

 rated we may derive from CH^ every combination of the form CH^X, 

 CH^X^, CHX^, and CX'^, in which X is an element, or radical, 

 equivalent to hydrogen, that is say, competent to take its place or to 

 combine with it. Such are the chlorine substitutes mentioned 

 already, such is wood-spirit, CH2(0H), in which X is represented by 

 the residue of water, and such are numerous other carbon derivatives. 

 If we continue, with the aid of hydroxyl, further substitutions of 

 the hydrogen of methane we shall obtain successively CH-(OH)^, 

 CH(OH)^, and C(013)-^. But if, in- proceeding thus, we bear in 

 mind that CH-(OH)'^ contains two hydroxyls in the same form as 

 peroxide of hydrogen, H-0" or (OH)'^, contains them — and moreover 

 not only in one molecule, but together, attached to one and the same 

 atom of carbon — so here we must look for the same decomposition as 

 that which we find in peroxide of hydrogen, and accompanied also 

 by the formation of water as an independently existing molecule ; 



* Because more than four atoms of hydrogen never unite with one atom of 

 the elements, and because the hydrogen comj ounds (e. g. HCl, H-S, H^P, H^Si) 

 always form their highest oxides with four atoms of oxygen, and as the highest 

 forms of oxides (OSO^ RO^) also contain four of oxygen, and eight groups of the 

 periodic system, corresponding to the highest basic oxides K-0, EO, R-0^, RO^, 

 R-O^, RO^, R-0", and ROS imply the above relationship, and because of the 

 nearest analogues among the elements— such as Mg, Zn, Cd, and Hg; or Cr, Mo, 

 W and U ; or Si, Ge, Sn, and Pt ; or F, CI, Br, and J and so forth — not more than 

 four are known, it seems to me that in these relationships there lies a deep 

 interest and meaning with regard to chemical mechanics. But because, to my 

 imagination, the idea of unity of design in Nature, either acting in complex 

 celestial systems or among chemical molecules, is very attractive, especially 

 because the atomic teaching at once acquires its true meaning, I will recall the 

 following facts relating to the solar system. There are eight major planets, 

 of which the four inner ones are not only separated from the four outer by aste- 

 roids, but ditfer from them in many respects, as for example in the smallness of 

 their diameters and their greater density. Saturn with his rmg has eight satellites, 

 Jupiter and Uranus have each four. It is evident that in the solar systems also we 

 meet with these higher numbers four and eight which appear in the combination of 

 chemical molecules. 



