Mercury Iron. 243 



direct provision for the intellectual progress of man. 

 I might, indeed, add the same of many other articles 

 found there, but as I am speaking of the metals, I 

 omit the other substances for the present. 



In strong contrast to the metals already men- 

 tioned, is mercury, but hardly less useful and seem- 

 ingly necessary for scientific research. Liquid, at 

 common temperatures, it dissolves other metals, and 

 by its aid the gold and silver are readily extracted 

 from the ores. How difficult it would be to find a 

 substitute for it in the thermometer, barometer, aivl 

 many other instruments known to men of science ! 

 We know not where to look for a substitute ; we could 

 not well get along without it. It happens to be 

 the ver} substance we want to complete the metallic 



ies very unlike all other metals and, because 

 so unlike, filling an important place among those 

 materials which seem essential to human progress. 



Too common, almost, to attract attention, is iron ; 

 but it possesses a number of properties, so marked, 

 that it seems impossible they should be studied with- 

 out producing the conviction that they were an ex- 

 press provision for man. It is hardly possible for 

 us to conceive in what state man must have remain- 

 ed to this day without iron ; how low in civilization, 

 and how powerless, compared with what he now is. 

 Before speaking of its properties, we cannot fail to 

 notice the fact of its abundance. It is distributed 

 in almost every portion of the globe ; and, certainly, 

 in such large quantities, that there will be enough 

 for all mankind while the world stands. 



