228 MICHIGAN ACADEMY OF SCIENCE. 



coming to us remain only through one or two years. Such students go- 

 ing back to the farm take with them knowledge relative to agriculture 

 that shall increase their capacity as producers. 



The first work in soils is given during the last four weeks of the win- 

 ter term. This work consists of lectures upon the history and distribu- 

 tion of the principal types of soil. In this work it is sought by simple 

 talks to show that all arable soils are derived largely from rocks, to 

 show what agencies — heat, moisture, air, plant and animal life, etc., are 

 operative in bringing about these changes, and that the value of any soil 

 will depend very largely upon the nature of the rock from which it is 

 formed. 



A soil may occui)y the position — practically — in which it was formed. 

 Such soils are found in the limestone area including a part of south- 

 western Wisconsin, and in the sandstone area lying to the north of it. 

 Such soils are called residuary soils — soils of immediate origin. The 

 location of the principal areas of this type of soil is indicated. 



The formation of the drift, or till soils, volcanic soils, alluvial soils, 

 wind blown soils, etc., are taken up and their characteristics, qualities, 

 and possibilities discussed. As in the former case the location of these 

 soils is indicated. The peculiarities of the soils of the arid regions and of 

 prairie soils, and some at least of the causes thereof, are discussed. 



As far as possible samples of the several soils are shown to the class 

 and the talks are illustrated by lantern slides. To this end we are gath- 

 ering samples of soils from different sections of the United States, and 

 we have one sample from Burmah, India. We are also adding to our 

 collection of lantern slides. In all this we show that many of the agen- 

 cies active in building up soils may become active, under proper condi- 

 tions, in wasting the soil. We show how nature, left to herself, holds 

 and improves her soils, and so far as possible, we show where we may 

 imitate nature both in conserving soils and in obtaining the largest 

 returns from them. 



We explain how valuable soils are injured or destroyed by the care- 

 lessness or ignorance, or both, of the husbandman, giving some estimates 

 of the extent to which lands have been injured or destroyed and calling 

 attention to some of the cases in which large areas have been abandoned 

 because of their impoverishment. We call attention, too. to the manner 

 in which soils affect the type of manhood, apparently, and the history 

 of nations as well. 



We find that almost without exception, these simple talks arouse a 

 good deal of interest in the student. The soil becomes to him a thing 

 of life, so to speak, and he seems to acquire a new respect for it. 



This work is given in the form of lectures because there is no satis- 

 factory text-book on the subject to be had. Students are required to 

 make careful notes. 



During the s])ring term of the freshmen year we give attention to soils 

 from the agricultural standpoint. 



We discuss the chemical composition of soils and estimate, from analy- 

 ses given, the amounts of the several plant foods in the first foot and in 

 the first four feet of soil, and then from the conipuled quantities of ma- 

 terial removed annually by crops, estimate the ])ossibilities in our soil 

 of crop growing. The fact of the wearing out of our soils and their un- 

 Ijroductiveness are compared with our theories, and explanation sought 

 for the apparent conflict. 



