388 POPULAR SGIJENCE MONTHLY. 



and made to rotate to and fro until the soft sand is waslied away 

 from the ore, which is then thrown on a scow provided for the 

 purpose or carried to shore. When a sufficient quantity has been 

 collected it is carted to the railway near at hand and loaded 

 on cars. > 



From the deeper parts of the lake the ore is raised by means of 

 a steam dredge. The captain of the dredge moves over the lake, 

 and, putting down a pole and working it about on the bottom, 

 can easily learn where there is a body of ore suitable for dredg- 

 ing. The dredge is then moved to the desired spot and work is 

 begun. The ore and sand are brought up in buckets on an end- 

 less chain and thrown into a long, revolving screen, adjusted and 

 inclined so as to deliver it upon scows moored to the dredge. In 

 its course down the screen the mixture of ore and mud is acted 

 upon by water which is thrown upon it with considerable force. 



By this means the mud and sand are washed out of the screen 

 and the clean ore is deposited on the scows. These are towed by 

 a steamer to the landing at the head of the lake, and the ore is 

 transferred to cars to be conveyed to the furnace, ten miles 

 distant. 



The plant on the lake consists of the dredge, a number of 

 scows, and a small tug, the latter being used in moving the dredge 

 from place to place, in towing the scows, and in carrying supplies, 

 for the crew live on the dredge from Sunday night until Satur- 

 day night, and work overtime, in order that a year's supply of 

 ore may be raised during the summer. 



The ore obtained from this lake is essentially a brown hema- 

 tite that is, hydrated peroxide of iron, with which is associated 

 more or less organic matter. The writer has made numerous 

 analyses of the ore, and the following is that of a sample repre- 

 senting a large quantity : 



Ferric oxide TO '04 



Manganic oxide 1 78 



Alumina 2-20 



Lime -32 



Magnesia -27 



Phosphoric anhydride 76 



Sulphuric anhydride -23 



Silica 7-84 



Loss on ignition 16 84 



100-28 



This lake ore, mixed with carefully selected bog ore from the 

 adjacent district and with a certain percentage of magiietic ore, is 

 smelted with charcoal in the Canada Iron Furnace Company's 

 furnace at Radnor, and produces a charcoal iron (brand " C. I. F.'') 

 far superior to the iron from the Lake Superior charcoal furnaces. 



