CHAPTER XII. 



SULPHUR ITS OCCURRENCE IN NATURE THE MINES OF SICILY 



THE REFINING PROCESS ICELAND SOUFRIERES AND 



SO LF AT ARAB USE OF SULPHUR IN MANUFACTURE PY- 

 RITES AND HOW THEY OCCUR ANALYTICAL TABLES 



GENERAL ANNUAL CONSUMPTION THE MINES OF SPAIN 



DESCRIBED. 



The practice of facilitating the solubility of phosphates by dis- 

 solving bones in oil of vitriol (sulphuric acid), originated with Baron 

 Licbig, in about 1851, and it is only natural that the same idea 

 should have been applied to the mineral or earthy product. 



In order that our readers may thoroughly understand the process 

 of decomposition, to which phosphatic materials are subjected in 

 the manufacture of superphosphates and other chemical manures, 

 it will be necessary and useful to explain what sulphuric acid is, 

 and how it is made. 



It has been said, and been said truly, that the prosperity of an 

 industrial country is to be judged of by its production and con- 

 sumption of sulphuric acid; and as it forms the basis of all chemi- 

 cal industry, and is largely employed in nearly every important 

 branch of manufacture, the reason for the assertion can be easily un- 

 derstood. 



As its name implies, it is derived either directly from the distilla- 

 tion of sulphur (brimstone), or from the burning of mineral sul- 

 phurets, known as pyrites; and before broaching the manufacturing 

 question, let us acquire some knowlege of these raw materials. 



