BY THE REV. W. B. CLARKE, M.A., F.G.S., &c. 289 



perspiration of the human hand ifc may be passed safely through 

 molten metal. 



The laundress spits upon her iron, and the saliva runs off in 

 globules and water in a spheroidal form remains unevaporated 

 in a red-hot crucible or pan so that where heat is concerned 

 the same form is assumed, as where it appears to be absent. 



All physical things seem to have a tendency to take this 

 particular structure, and heat administered in gentle doses, to- 

 gether with infinitesimal draughts of gases and mineral vapour 

 during long periods of time, superintended by the administrative 

 aid of chemical, galvanic, and other natural forces, has a mission 

 in the final renovation of the constitution of the world. 



Little has been said of metallic combinations or changes ; but 

 no person can spend a day among our Hawkesbury rocks and 

 not be struck by the fact that iron, at least, has been introduced 

 by means of imbibition, and through fissures into our common 

 sandstone, and the colouring of these rocks brought out by 

 oxidation, presenting most remarkable forms and varying outlines? 

 betrays the influence of iron in a striking way. . 



One of the most common of all exhibitions of iron is that of 

 Pyrites. It belongs to all ages, and has been produced in all 

 kinds of rock. It is a great enemy to some mining operations, 

 such as the production of gold, and much wealth is lost because 

 it is difficult to separate it from the precious metal. 



Now, this mineral, owing to its combination with sulphur, is 

 a pure product of transmutation, and in turn it becomes an agent 

 thereof. The sulphuration of the springs of Greece has been 

 traced to the decomposition of this mineral. And what is more 

 curious, from pyrites have resulted huge deposits of hydrated iron. 

 In the Cevennes mountains, in Languedoc, pyritous emanations 

 or eruptions have produced a mass of the mineral near Alais, of 

 great thickness, and on the opposite side of the valley in which 

 the quarries are situate, there is a great mass of hydrated iron, 

 which is proved to result from the decomposition or transmutation 

 of the pyrites. 



M. Yirlet, who first called attention to this curious spot, 

 exhibited to the Geological Society of France, in August, 1814, a 

 specimen which created some surprise. In it the pyrites occupied 



