ARCHITECTURE. 



357 



This compound gas is the same which collects in 

 the coal-mines in England, and proves so fatal to 

 the miners. 



CHAPTER XXXII. 



PRACTICAL APPLICATION OF GEOLOGY TO THE USEFUL 

 PURPOSES OF LIFE. 



Architecture. — Engineering — Roads — Canals — Embankments 

 — Weils — Mining. — Agriculture. 



Geology derives its chief importance from its ap- 

 plication to many of those arts which minister to 

 the comforts and necessities of man. A knowledge 

 of the formation and structure of the earth not only 

 gratifies a rational curiosity, but it directly places 

 within our reach the instruments by which its use- 

 ful materials may be converted to highly valuable 

 purposes. Here knowledge truly is power; and 

 he who is thoroughly conversant with geological 

 principles and facts, possesses the lever and the 

 " where-to-stand" which Archimedes wanted to 

 move the world. 



ARCHITECTURE. 



It would seem that the importance of knowing 

 and testing the durability of building stones and 

 marbles for public works, or even private dwell- 

 ings, is too obvious to need remark ; and still there 

 has hitherto been displayed great ignorance or in- 

 attention to this subject in this country, so much so, 

 that frequently the worst and most perishable ma- 

 terials have been selected in preference to such as 

 are equally beautiful, and, in addition, indestructible. 



