SECRETARY'S REPORT. Ill 



of the kind of schooling wliich a student in an agricultural 

 college ought to have, and with which, doubtless, he will be 

 furnished, when such an institution shall be duly organized, 

 within the boundaries of this Commonwealth. 



I propose, gentlemen, to say a few words in regard to certain 

 general aspects of the soil, as related to the rocks of the United 

 States, — a very broad subject it must be confessed. But before 

 entering on this topic definitely, it may interest my audience a 

 little if I show them two objects which I have before me, as 

 illustrating how the culture of the soil connects itself directly 

 with chemical inquiries, and of what an interesting character 

 they are. Everybody knows, of course, what clay is. It is not 

 a simple substance. It iisually consists of a portion of silica, in 

 other words, pure flint, in a state of fine subdivision, and 

 alumina, or pure clay. Now this pure clay consists in a very 

 large proportion of a peculiar metal called aluminium, so that 

 in this sense, we all have metallic mines under our feet, and 

 with every ploughshare, we are turning up large quantities of 

 this metallic matter. Here is the metal. [Exhibiting a small 

 piece of aluminium.] This is the metal which is the basis of 

 clay. A pure metal, beautifully resonant, [striking it upon the 

 desk,] hard, silver-like in its lustre, and extremely light, — a 

 little more than two and a half times the weight of the same 

 bulk of water. Many of you have, doubtless, seen it, as it is 

 beginning to be used to a considerable extent, in the manufac- 

 ture of ornaments. It exists as a very large ingredient of the 

 crust of the earth. The quantity of iron deposited throughout 

 the various strata of the globe is to be looked upon as utterly 

 insignificant in comparison with the quantity of this metal ; but 

 it is only of late years that it has been obtained from the rock 

 or earth in which it exists as a white oxide clay, just as iron is 

 found as a red oxide, in the common ores of that metal. Such, 

 then, is a part of the chemistry of your soil. 



Here is another metal, still more curious. It is a very light 

 wire. Every one knows the substance called magnesia. Most 

 persons who have the care of a nursery, understand some of its 

 uses. Now magnesia is nothing more than the white rust of 

 this metal ; and magnesia is one of the most abundant sub- 

 stances in the rocky structure of the earth. Many parts of the 

 Vermont range of hills consist largely of magnesian slates, and 



