combinations. Thus, if we find in a given salt solution, sodium and 

 potassium on the one hand, and sulfuric and hydrocholorie acids on the 

 othe'r, we would have in the solution the four salts: sodium chloride, 

 sodium sulfate, potassium chloride and potassium sulfate, in certain 

 proportions. 



In our analyses we give only the different radicles found without 

 paying attention to their possible combinations which do not concern us 

 much. These few words on the subject win probably suffice to give la 

 those readers who are not familiar with chemistry, the necessary ex- 

 planations. 



The writer is indebted, besides Mr. Crawley, to the following 

 gentlemen who have rendered him assistance in this investigation; Mr. 

 J. C. Howells, Irrigation Engineer; Mr. J. R. Johnston, Pathologist of 

 this Station; Mr. E. E. Olding, formely manager of Central Cambala- 

 che; Mr. H. Shapley, Chemist of Central Plazuela ; Mr. W. E. Hess, of 

 the Agricultural Experiment Station at Mayaguez; Mr. Santiago Sifre, 

 Administrator of Central Plazuela ; and Mr. Justiniano Santiago, Admi- 

 nistrator of the Tiburones lands, managed by the Plazuela Sugar Com- 

 pany. The writer wishes to express his thanks to all these gentlemen, 

 whose help is greatly appreciated by him. 



