300 REPORT OF NATIONAL MUSEUM, 1904. 



In his chapter on soils, it is instructive to note, he recognized and 

 emphasized a principle now generally accepted, to the effect that the 

 fertility of the soils does not depend upon ultimate chemical constitu- 

 tion„ but rather upon physical properties; that a fertile soil should 

 contain, first, sufficient stones and pebbles to keep it open and loose; 

 second, sufficient clay to absorb and hold water in the right propor- 

 tion; and third, sufficient fine sand to prevent the clay from baking in 

 time of drought. 



That the fertility of a soil could not be told by a chemical analysis 

 had been stated by him some years earlier, as follows: 



Suppose, in one specimen, the soil, etc., should he quartz, in another feldspar, in 

 another hornblende, in another sapphire, in another diamond, would there be any 

 difference in the influence of the sand, etc., upon the productive quality of the soil 

 on account of the different ultimate elements of which these different minerals are 

 composed? Should they be so far decomposed, at some future period, as to become 

 an impalpable powder, perhaps they may then differ in their influence upon vegeta- 

 tion. Perhaps we may foretell the future state of the country a century or two to 

 come, where such extreme disintegration is effected. But the difference in the ulti- 

 mate constituents can not possibly affect the question of fertility or barrenness at the 

 time tin' analysis is made. For whatever effect can be ascribable to the one is equally 

 a property of the other. They all hold water on their surfaces by the attraction of 

 adhesion; they all keep the soil duly open and porous to give passage to the roots of 

 vegetables; they all aid alike in bracing up plants and in keeping them in a fixed 

 position, etc;. Whatever is effected by one is effected by all— size, form, quantity, 

 and all circumstances, other than their constituent elements, agreeing." 



To this second edition he added a chapter of some 11 pages on the 

 science of mining, one of 12 pages on localities, and 5 pages on fossils. 

 His gradually expanding views as to the value of fossils in geological 

 work are shown in his paper on Geological Equivalents of this year 

 (1832). He here advanced the idea that the enumeration of the min- 

 eral constituents of rocks could never be satisfactorily applied for the 

 determination of the relative position of strata, but that recourse must 

 be had to the organic remains. " We find the same organized remains 

 associated with equivalent strata in every part of the earth."' * 



If we are to judge from the preface of the edition of 1830, Eaton 

 was by no means lacking in egotism, and had, at times, an unfortunate 

 way of expressing his opinions, such as must have aroused antagonism 



"American Journal of Science, XII, June, 1827, p. 870. 



''The hrst edition of Eaton's work was somewhat savagely reviewed by a writer in 

 the North American Review for April, 1831. From its perusal one might be led to 

 suppose that the following extract from a letter by Eaton to Silliman in 1839 had a 

 sounder basis than Eaton would himself be likely to acknowledge. He wrote: "I 

 was one of your earliest correspondents on geology, consequently it is to be presumed 

 that I have introduced more errors to the public through your journal than any other 

 individual." Most writers will say things of themselves which they would resent if 

 said by others. 



