ADDRESS. 17 



plies. Nor does it usually require but a small quantity, as the 

 example of ashes, and gypsum, and phosphate of lime evinced. 

 The latter, in the state of bone dust, where the phosphate is 

 mixed with carbonate of lime and cartilage, is a manure so con- 

 centrated, that one ton of it is equal to 14 tons of farm yard 

 manure ; and almost equally concentrated is guano, and some 

 other compounds now used upon land. But I cannot go into 

 details. 



Allow me also to repeat a suggestion made in my report on 

 the Agricultural Geology of Massachusetts, respecting the use 

 of what I call Muck Sand, dug from a considerable depth in 

 the earth. It is well known to the chemist, that most of the 

 salts so useful upon land, are dissolved by rains, and carried 

 downward through the soil, till they meet with a water-bear- 

 ing stratum. There they will accumulate ; and now, let that 

 stratum, — known by springs issuing from it, — be dug up and 

 spread over the surface, and these salts will exert their appro- 

 priate influence upon the crops. This very principle is the 

 chief secret of the good eff'ects of subsoil ploughing ; and I 

 doubt not but it will yet lead to valuable results in the use of 

 substances drawn from a still greater depth. In some in- 

 stances, they certainly have produced astonishing effects. 



Though I have doubtless wearied your patience, ladies and 

 gentlemen of the Society, by these details, I would gladly add 

 more. But I trust I have said enough to show how important 

 a bearing science has upon practical agriculture. The day I 

 trust has gone by, certainly among the enlightened farmers of 

 this great valley, when men reject and treat contemptuously 

 what has been called book farming ; by which I understand 

 farming on scientific principles. Such farming has done too 

 much, both in Europe and this country, to be any longer des- 

 pised, or even looked upon with scepticism. The many agri- 

 cultural societies, on both sides of the Atlantic, so prolific of 

 good, are based upon science ; and would be almost useless 

 without it : and the numerous journals of agriculture, now pub- 

 lished, derive their chief and most valuable matter from the 

 application of science to cultivation. Indeed, it is scientific 



