DISCOVERY OF NEW CHEMICAL ELEMENTS. 825 

 DISCOVEKY OF NEW CHEMICAL ELEMENTS. 



By CLEMENS WINKLER. 



IN his studies of the relative frequency of the different elements 

 composing the crust of the earth, Mr. F. W. Clarke supposes 

 that to a depth of ten miles below the level of the sea the composi- 

 tion of the ground is the same as is given by the examination of the 

 surface strata and the depths which we have reached. The mean 

 specific gravity of these strata is 2.5, or not quite half the density 

 of the earth as a whole. Including the oceans and the atmosphere, 

 the exterior crust of the earth is composed half of oxygen and one 

 fourth of silicon, while the other fourth is represented by other 

 elements — aluminum, 7 per cent; iron, 5.10; calcium, 3.50; mag- 

 nesium, 2.50; sodium, 2.20; and potassium, 2.20 per cent. Some 

 of the elements of which the numerous compounds have long been 

 very obvious to the human ken are, therefore, from the point of 

 view of their quantity, of very little importance; thus, hydrogen 

 stands for only 0.94 per cent of the general composition of the 

 crust of the earth, carbonic acid for 0.21 per cent, phosphorus for 

 0.09 per cent, and nitrogen for 0.02 per cent. These elements, 

 which are the constituents of immense seas and form the basis of 

 life, therefore furnish only a minute fraction of the mass of the ten- 

 mile-thick ring contemplated by Mr. Clarke. Since the soundings 

 thus far made indicate that they do not exist or hardly exist at 

 greater depths, we have a right to say that so far as regards quantity 

 they may almost be neglected, in considering the mass of the whole 

 globe. The content in chlorine does not exceed 0.15 per cent, yet 

 the common salt alone held in the oceans is sufficient to cover all the 

 continents and bury the highest mountains. 



We perceive from this showing how little the impression the 

 outer surface of our globe gives us corresponds with its real nature 

 as we judge of it from its mean density. There can not be the least 

 doubt that the internal parts of the globe are composed of different 

 substances from those which appear in the external strata. 



But, while the elements of light specific weight or great vola- 

 tility which, like hydrogen and nitrogen, exist in large quantities 

 around us, constitute only a very minute part of the constituents of 

 our globe considered as a whole, we presume that the elements 

 called rare only enter in an infinitesimal degree into the general 

 composition of the earth; the more so, because, so far as we as yet 

 know, these elements are not found at great depths. I, at least, do 

 not know that the heavier metals — gold, silver, lead, etc. — have 

 ever been found in the materials extracted from deep soundings or 



