TO THE CONNECTICUT AGEICULTUEAL 





moistened; add gradually eleven pounds of oil of vitriol of 66 

 the. agitation with the shovel being continued. A brisk elFerves- 

 cence of the mass will ensue (from decomposition of the carbonate 

 o£ lime in the bones), which will not, however, rise above the 

 margin of the pit if the acid is poured on in separate small quan- 

 tities. After twenty-four hours, sprinkle again with three qiiarts of 

 water, add the same quantity of sulphuric acid as before, with the 

 same brisk shoveling of the mass, and leave the substances to act 

 for another twenty-four hours upon each other. Then intermix 

 the fine bone previously sifted off, and finally shovel the ashes and 

 earth of the pit into the decomposed bone until they are all uni- 

 formly mixed together." 



" Available " Phosphoric Acid, 



The current uses of the term " available " as applied to phos- 

 phoric acid have occasioned some confusion and may appropriately 

 be noticed here. 



In an agricultural sense available phosphoric acid is that which 

 can be of use to vegetation. The three states of phosphoric acid 

 which are distinguished in this report, viz : " soluble," i. e. freely 

 dissolved in water, "reverted," or very slightly soluble in water, 

 but freely dissolved in ammonium citrate, and " insoluble," which 

 means not freely dissolved either by water or by ammonium citrate, 

 are all more or less fully and rapidly available for the nutrition of 

 ci'ops. The least "available" of these three forms — the "insolu- 

 ble" — is the form which in nature is chiefly accessible to plants, 

 and is sufficient for the slow growth of prairie and forest, and 

 under favorable conditions answers most of the purposes of agri- 

 culture. For immediate effect, on quick-growing crops, or on 

 infertile soils, the soluble and reverted are desirable and advan- 

 tageous. 



Some chemists, in reporting the analyses of fertilizers, are in the 

 habit of classins: toojether "soluble" and "reverted" under the 

 designation "available." In so doing the}'^ have various reasons, 

 some of which are good. They assert or imply that the distinc- 

 tion between "soluble" and "reverted" is too fine-drawn for 

 practical purposes ; that in many cases " reverted " is as good or 

 better for crops than " soluble ;" that therefore it is useless to 

 estimate them separately. 



