338 THE SCIENTIFIC PAPERS OF 



he thought was open to attack, viz., the suggestion that the 

 deposits of hematite or other ore might have been aided by 

 electricity. That proposition touched him rather closely as an 

 electrician, and, therefore, he felt bound to respond to the call of 

 their President to say a few words. He (Dr. Siemens) could not 

 conceive any condition of things which would bring electricity 

 into play in producing such deposits ; the electric current caused 

 a deposit of metal if it passed from one conducting surface to 

 another through a metallic solution. But where would they find 

 such conditions ? The rock upon which the deposit of brown ore 

 had taken place was not a conductor ; the iron ore could not have 

 been in solution, unless it had been a sulphate, and if it should, 

 nevertheless, have been deposited electrically under conditions 

 which they might have some difficulty in conceiving, but which, 

 nevertheless, might have existed, the deposit would have been 

 metallic iron, and not magnetic or peroxide. He thought they 

 should be very slow in accepting a speculation which could not be 

 brought into direct and tangible connection with electric science- 

 as it was actually understood. His inclinations were in favour of 

 another theory regarding the origin of hematite ore, to the effect 

 that it was solid deposit resulting from the denudation of red 

 sandstone. If they imagined the state of the surface of their earth 

 at a time when the water which now filled the ocean was still con- 

 tained in a vaporous condition in the atmosphere, they must 

 easily conceive wha.t enormous power of dissolution must have 

 existed ; if they considered the water of the ocean to be in a state 

 of vapour, the pressure upon the surface of the earth must have 

 been equal to at least fifty of our present atmospheres, and the 

 temperature of that water must have been fully 400 degrees. 



The President : Centigrade ? 



Dr. Siemens : No, Fahrenheit. They knew that if they operated 

 with a weak alkaline solution on flint under such conditions of 

 temperature and pressure in a boiler that the flint readily dissolved, 

 and as alkaline substances must have been contained in the water 

 in an infinitely larger proportion than at present, the silica of the 

 red sandstone must have been dissolved, liberating the oxide of 

 iron which would be deposited more or less mixed up with other 

 substances that had been mechanically carried away by the same 

 current. Such a working theory would, he thought, account more 



