April 28, 1899.] 



SCIENCE. 



mi 



spoken slightingly of the compound-maker, 

 as a kind of inferior being, apparently for- 

 getting that it is just this kind of pioneer 

 work which has supplied the material for 

 their labors, that the first requisite for suc- 

 cessful generalization is the possession of a 

 large number of pure substances, of accu- 

 rately known composition and properties, 

 many of which can only be obtained by 

 work which is so elaborate and difficult, 

 and which requires such concentration of 

 effort that he who follows it can well be ex- 

 cused if he does not always look on the 

 product of his labor as merely means to 

 another end. It is tolerably clear that, for 

 a long time to come, experimentizing must 

 keep equal pace with mathematicizing, and 

 if the former have been pushed so far in one 

 direction as to appear to afford no prospect 

 of continued progress we must not abandon 

 it altogether, but consider whether it may not 

 be still profitably pursued along other lines. 

 Let us consider whether we must all turn 

 mathematical chemists, or whether there 

 is not much left to be done by those trained 

 in the older school, working along old-fash- 

 ioned lines and by old-fashioned methods. 

 Descriptive chemistrj^, as it exists to-day, 

 is a science which has grown and is still 

 growing enormously in a single ^direction, 

 that of organic chemistry, the chemistry of 

 the compounds of carbon. We are at pres- 

 ent acquainted with about seventy-five 

 chemical elements, which are found in the 

 most varied proportion in those parts of the 

 earth which are accessible to our observa- 

 tion, namely, the crust, the sea and the air. 

 The accompanying table, calculated by 

 Clarke, shows the relative abundance of the 

 elements in a sphere comprising the crust 

 for a depth often miles, the ocean and the 

 atmosphere : 



Oxygen 49.98 



Silicon 25.30 



Aluminium 7. 26 



Iron 5.08 



Calcium 3.51 



Magnesi um 2.50 



Sodium 2.28 



Potassium 2.23 



Hydrogen 94 



Titanium 30 



Carbon 21 



Chlorine 1 

 Bromine j 



Phosphorus 09 



Manganese 07 



Sulphur 04 



Barium 03 



Nitrogen 02 



Chromium 01 



The nineteen elements here given make 

 up nearly the whole mass ; the remaining 

 fifty-five or thereabouts, taken together, and 

 making all possible allowance for error, do 

 not amount to more than at most 1 per 

 cent. Observe that the element carbon 

 amounts to but one-fifth of 1 per cent. To 

 be sure, this is no argument that the chem- 

 istry of carbon is relatively unimportant ; 

 on the contrary, there is no necessary con- 

 nection between the abundance of an ele- 

 ment and its ability to carry us further 

 toward a knowledge of chemical laws. 

 Nevertheless, to an intelligence not having 

 its seat in a body largely made up of carbon 

 compounds, it might appear somewhat sur- 

 prising that chemists should have attempted 

 to base a science on the investigation of an 

 element which exists in such relatively insig- 

 nificant amounts, the compounds of which, 

 with but few exceptions, are incapable of 

 formation at the freezing point of water, or 

 of existence at the lowest red heat ; and 

 should have chosen to devote nearly all of 

 their energy to its study. 



Apart from the special subject of coal, pe- 

 troleum and asphalt, carbon is of practical 

 importance to the geologist only in the form 

 of carbon dioxide and the carbonates, while 

 of the chemical properties of silicon, which 

 constitutes 27 per cent, of the earth's crust, 

 and of the silicates, which make up nearly 

 all of it, we know vastly less than of the 



