ARTICLES 605 



as representative of the gymnospermous plants. The presence 

 of the elements in the respective spheres, together with the 

 qualitative composition of meteorites, 1 is illustrated by the 

 figure, which is based upon the modified periodic table. 8 It 

 will be noticed that all the important elements occupy neigh- 

 bouring positions in the periodic system, and that the few 

 important elements of higher atomic weight are near the group 

 of the inert noble gases. Most characteristic is the fact that 

 there are only four elements (H, O, N, C) which are in all 

 spheres. These are the well-known bio-elements, which form 

 from 97-99 per cent, of all living matter. The possibility of 

 millions of different compounds of these elements, together with 

 the ever-growing complexity of organic compounds revealed by 

 modern investigations, has led to the development of a system 

 of structure symbols 3 wholly based upon these four elements. 

 A similar quartet of elements (Na, Mg, Al, Si) is found on the 

 other side of the noble gases ; these are third to sixth in order 

 of abundance, for their oxides form the basis of all the rock> 

 forming compounds of the solid earth crust. 4 



These eight elements form a prominent centre around which 

 the elements next in importance are closely grouped. Six 

 more elements — namely, Fe, Ca, K, CI, P, and Ni — are necessary 

 to bring the percentage of distribution in all four spheres, 

 including the meteorites, close to or above 99 per cent. By 

 substituting S for Ni, the list will contain the fourteen funda- 

 mental elements which not only make the bulk of the known 

 matter, but also are the essential elements of every material 

 science, whether biology or geology, pharmacy or metallurgy. 



What is the significance of these data ? Does it point to 

 a material evolution in the universe ? An evolution more 

 fascinating by its apparent universality, for our earth, being 

 not isolated, but an integral although insignificant part of the 

 cosmos, must partake in cosmical evolution. Is the abundance 

 of elements the earmark of a state of evolution ? As there 

 are in celestial objects indications of a stellar evolution, whose 

 stages are recognised by the spectra revealing the abundance 



1 Farrington, Field Columbian Museum, Chicago, Publ. 120 and 151 ; 

 Harkins, Proc. Nat. Acad. Sciences, 1916, vol. ii, p. 216. 

 \ 2 Hackh, Journ. Amer. Chem. Soc, 1918, vol. xl, p. 1023. 



3 Can. Chem. Journ., 1918, vol. ii, p. 135 ; Science, N.S., 1918, vol. xlviii, 

 P- 333 : Chem. News, 1919, vol. cxviii, p. 289. 



4 These four elements (Na, Mg, Al, Si), having a valency of 1, 2, 3 and 4 

 respectively, could also be made the basis for a system of structure symbols. 

 However, as we know at present little or nothing of the structure of silicates, 

 this proposal is somewhat premature. Nevertheless the writer could not 

 refrain from pointing out this possibility, with the suggestion that both sys- 

 tems of structure symbols can jointly be used by differentiating the atoms of 

 Na, Mg, Al, Si with circles. 



