BULLETIN OF THE BUSSEY INSTITUTION. 163 
In spite, however, of this lack of precision, some useful suggestions 
may be gathered from the general tables. The good effect of the 
potassic manures is noticeable almost everywhere at the first glance ; 
and the remark applies not only to. the beans, which, as has been 
repeatedly urged, were the only crops that have been grown with real 
success, but to the barley also and to the ruta-bagas. Several of the 
nitrogenous fertilizers did some good, particularly in 1871, when the 
land was in a less exhausted condition than it was afterwards. A 
certain useful effect was occasionally produced by some of the better 
superphosphates also, and this result is no matter for surprise, in view 
of the fact that these so-called superphosphates contained, besides 
phosphoric acid and nitrogen of various degrees of activity, a quantity 
of sulphate of.lime competent to set free potash from the silicates in 
the soil, and some traces of potash in the animal matter of which 
they are in part composed.* But at the best the superphosphates 
have done but little, if any, more good than some of the nitrogenous 
manures, such as sulphate of ammonia and the heavy dressing of 
fish-scrap. The farm manure has done better upon barley and for 
the production of leaves and straw than the long horse-manure from 
the city, doubtless because of its containing a larger proportion of 
nitrogen. It will be remembered in this connection that the horse- 
manure used in 1872 was inferior to that of the other two years; it 
consisted for the most part of swale-hay. 
It will be noticed, moreover, that the character of the several 
seasons is shown in some part by the tables which give the weights of 
the different crops. The summer of 1873, for example, was specially 
favorable for the growth of ruta-bagas, and particularly bad for the 
growth of barley. The summer of 1871, on the other hand, was 
favorable for beans and barley, but very bad for ruta-bagas. 
* For example, the so-called ‘“‘ XL” superphosphate obtained from Mr. Wm. 
L. Bradley of Boston, in 1872, was found to contain 0.27 per cent of potash. 
