62 



YEARBOOK, PUBLIC MUSEUM, MILWAUKEE. 



[Vol. I. 



Wells have been drilled to a depth of five thousand feet just at the edge 

 of the dome and have struck nothing other than sand and gravel. This 

 shows that the material in the dome has risen at least four thousand 

 feet above its original position, at the bottom of the layer of sand. 



At the present time, four complete plants are being operated on the 

 surface of the mound, any one of which is independent of the others. 

 Together they form the largest factory for the manufacture of steam in 

 existence in this country. The size can be appreciated from the fact 



Fig. 34. — Tanks of sulphur after Ijoard siding has been partially removed. 

 Freeport, Brazoria Count}-, Texas. 



that the boilers consume three thousand five hundred barrels of fuel oil 

 per day. This is obtained from wells owned by the company at Tam- 

 pico, Mexico, and is brought to Freeport in tankers which dock at the 

 mouth of the Brazos river. The water comes directly from the river 

 and is treated to remove lime and other impurities before being fed into 

 the boilers. From the boilers, the steam is pumped by the set of pumps 

 shown in figure 33 into heaters where it is superheated to a still higher 

 temperature in order to reach the melting point of sulphur. From the 

 heaters, it passes through a set of pipes to the wells and so underground. 



