172 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vou. VIII. 
to have recommended it to consumers alike in Europe and on the Ameri- 
can continent. Results are always the best tests of the efficiency of any 
agent, and the rapidly increasing market that Ontario’s corundum is finding 
is sufficient evidence of the quality of this material. The Craig Mine is 
now putting out about ten tons a day, and the management confidently 
expect a considerable increase in the spring.*® 
GRAPHITE. 
Though no company for the manufacture of graphite has yet been 
capitalized in Canada, the production of it by the Acheson process is carried 
on to a small extent in the Canadian branch of the Carborundum Company 
at Niagara Falls. The formation of the ‘‘skeleton”’ crystals referred to 
above suggested making use of the decomposition of carborundum for 
making graphite itself. The inventor’s patents include the production 
of graphite in the form of pure electric-light carbon, by subjecting impure 
carbon to a high temperature for a sufficient length of time to volatilize 
the impurities ;#° the conversion of carbon into graphite by mixing with 
such metallic oxides as would be capable of forming metallic carbides, 
to be subsequently decomposed ;** the conversion into graphite of such 
natural carbonaceous materials as contain uniformly intermixed through 
them metallic oxides sufficient to produce carbide, and thence graphite.*° 
These processes throw considerable light on the scientifie principles under- 
lying the formation of this substance.*® 
X.—THE CEMENT AND PLASTER INDUSTRY. 
The manufacture of Portland cement is mainly confined to Ontario, 
though one establishment—the Crescent Cement Works—is situated at 
Longue Pointe, in the Province of Quebec. In Ontario there are some 
fourteen companies and eight factories in operation, and throughout this 
Province are found the necessary raw materials (clay and marl) of an ex- 
cellent quality. The development of the industry has been rapid, and has 
all taken place within the past few years. The most improved method 
of procedure is as follows: the marl is thoroughly mixed, mechanically, 
with water into a thin paste, and the same operation is performed with the 
clay. The two fluids are mixed thoroughly in the required proportions, 
and in a pasty condition are pumped into steel rotary calciners, about 
seventy feet in length and six feet in diameter, set at a slight angle to the 
(42) See note 40. An account of the Corundum Industry of Ontario will be found in the ‘‘ Canadian 
Mining Review,” Vol. XXIII, No. 10, (1904). 
(43) U.S. Pat. 542,982 of July 23, 1895. 
(44) U.S. Pat. 568,323 of Sept. 29, 1896, and No. 617,979 of Jan. 17, 1899. 
(45) U.S. Pat. 645,285 of March 13, 1900. 
(46) Electro Chemical Industry, Vol. I., No. 2. 
