82 ON EXPERLMENTS ON MANURES. 



counts as much as a pound of corn. We have calcula- 

 ted the results by first finding the value of the crop pro- 

 duced by each lot, considering corn worth 12 mills per 

 lb.; potatoes 3 mills per lb.; carrots, ruta baga and 

 beets, 2 mills per lb. 



From the value of the crop thus found, we deduct in 

 the first place, the number of twentieths necessary to 

 reduce the quality of the soil to the standard of the 

 poorest lot. In the second place, we deduct the value of 

 the crop reduced, on account of the quality of the soil, as 

 the others are, obtained from' lot No. 16, without manure. 

 This difference thus shown must be attributed to the ma- 

 nure, mistake in the estimated quality of the soil, differ- 

 ence of culture, or other accidental circumstances. As- 

 suming it wholly owing to the manure, the comparative 

 value of each kind used may be at once seen on the 

 diagram. 



On the diagram is marked the number of each bed; 

 the number of twentieths to be deducted from the value 

 of its crop; and an abbreviated indication of the manure 

 used, and the amount in cents and mills to be attributed 

 to the manure. 



The expense of manure on each bed, as estimated 

 above, was 18 cents. Our calculation shows a very 

 meagre return for this outlay. But Mr. Putnam says, 

 the object being to determine the comparative value of 

 the manures, he was not solicitous about the amount of 

 crop, and it proved small, as he knew it must be. On 

 some of the beds too large a quantity of salts were used. 

 Eight gallons salt ley from soda soap, the kind probably 

 used by Mr. P., according to Dana, contains about 7 lbs. 

 6 oz. of common salt and glauber salt. This, it would 

 seem, is too much for corn and carrots, but not so for 

 potatoes, beets, and ruta baga. Ox urine contains a 

 much larger, and human urine double the above named 

 quality of these salts — too much, it would seem, for either 

 kind of vegetable here cultivated. The benefit arising 

 from the use of these articles, will probably be more 

 obvious in future years. 



The 11 lbs. of salt used on No. 6, operated still more 



