The Abundance of the Chemical Elements’ 
By Hans E. Suess 
Professor of Geochemistry 
University of California 
La Jolla, Calif. 
[With 4 plates] 
Everysopy KNows that gold is a very rare element and iron is very 
abundant on the surface of the earth. Elements like magnesium, 
silicon, oxygen, or aluminum represent the major constituents of the 
earth’s crust and its rocks, whereas others like gallium, platinum, 
thallium, and uranium are present only in rare minerals or in the form 
of minor impurities. Just how much more abundant one element is 
relative to another is a question dealt with in the field of geochemistry. 
The first attempt to answer this question in a quantitative way was 
made by F. W. Clarke and H. S. Washington during the last decades 
of the 19th century. Numerous rock analyses were compared by these 
authors and an average figure for the occurrence of each element in 
terrestrial rocks was given. In 1889 Clarke said that he attempted to 
represent the relative abundances of the elements obtained in this way 
by a curve, taking their atomic weight for one set of ordinates. He 
had hoped that some sort of periodicity might become evident, but no 
such regularity appeared. During the following 50 years the work of 
geochemists led to an understanding of the distribution of the elements 
between various types of rocks, but it could not yet be explained why 
some elements were more abundant than others. 
Another basic question that could not be answered at the time that 
Clarke and Washington began their studies was whether the earth was 
unique in its chemical composition compared to other heavenly bodies. 
Did other planets, the sun, and the stars have an entirely different 
composition or was the composition of the earth’s crust representative 
in a general way of the material of which the universe is composed ? 
Three lines of new scientific evidence enable us now to interpret geo- 
chemical data and answer all these questions in a satisfactory way. 
1 Reprinted by permission from Foote Prints, vol. 29, No. 2, 1957, published by Foote 
Mineral Company, Philadelphia, Pa. 
307 
