No. 4.] MAXUKIAI. rUOBLEMS. 155 



l)h()Si)liato, thus reducing the apparent percentage of reverted 

 phosphoric acid. A more etlective phm may l)e to deter- 

 mine the ahimina in mixed iioods as a means ot" rec()i!:nizing 

 this particular })hosphate. By some such means the con- 

 sumers should be alt'ordcd the full measure of i)rotection 

 which is their due. Doubtless this would increase the cost 

 of the inspection somewhat })er brand ; but, if an increased 

 fee for inspection were required in consequence, doubtless 

 any independent manufacturers who do not employ this par- 

 ticular phosphate would gladly join hands with the consumer 

 to have the fee raised sufficiently to provide for the added 

 work of anah'sis, particularly in view of the infinitesimal 

 cost, compared with the great protection which might be 

 afforded. 



Regarding " floats," a finely ground unacidulated product 

 from the phosi)liate rock, I desire to state that in the former 

 paper results from its use with grass were cited, showing it 

 to be quite an effective manure for that crop, if used upon 

 acid soil. Subsequent results have, however, shown it to be 

 comparatively inefficient in connection Avith garden vegeta- 

 bles and most ordinarv crops. Its residual efiect is never- 

 theless distinctly helpful upon acid soil, but in a much less 

 degree than basic slag meal or finely groimd steamed bone, 

 to both of which it was also inferior in immediate action. 



Basic slag meal, in marked contrast to bone and floats, 

 was strikingly eftective from the very outset, proving, w^here 

 lime was omitted, superior to the super} )hosphates for certain 

 plants which could not succeed, especially upon a very acid 

 soil. 



In lact, the inefficiency of floats has proved so great, for 

 most crops, that, in the rotation experiments where it was 

 introduced at a certain stage, bone is again being employed. 

 The present indications are to the effect that floats are more 

 likely to prove profitable upon acid soil (such as peat or 

 muck, or upon soils containing much sour humus), particu- 

 larly W'here grass or certain of the leguminous plants are to 

 be grown, than elsewhere, and under other conditions. 



