538 EEPOET— 1889. 



than the others, is softer and of rather a darker colour, and crystals of calcium 

 carbonate are frequently disseminated through it. 



The ore occurs in stratified beds varying in thickness from a few inches to 6 feet, 

 and is found outcropping in the sides of the hills belonging to the range ■which 

 follows the coast of Chili, known as the ' Cordilleras del la costa.' 



A characteristic of Chilian manganese ores is the large percentage of protoxide 

 of manganese they contain. In Caucasian and Spanish ores there is not often more 

 than from 1 to 2 per cent, of protoxide. It is known that manganese dioxide acts 

 the part of a feeble acid, and when precipitated carries down with it as manganites 

 protoxide of manganese, baryta, lime, potash, and other bases with which it was in 

 solution, and it is probable that in these ores the protoxide of manganese, the 

 potash, and portions of the baryta, lime, and other bases shown in the above 

 analyses have been precipitated in combination with the peroxide in the form of 

 manganites. 



Baryta is frequently found in other manganese ores. Some Caucasian ore con- 

 tains as much as 2'04 per cent. Potash also is found in other ores, though not 

 often in- such quantity as in No. I. We have, however, met with one specimen, 

 not Chilian, which contained as much as 4'15 per cent. The silica in Chilian ore 

 occurs sometimes as quartz and sometimes as sihcate of manganese. 



The percentage of phosphorus in Chilian ores is very low — a matter of great 

 importance to the steel-maker. The amount varies to a slight extent in various 

 cargoes, and about O'l per cent, has sometimes been found. No. II. contains a 

 small quantity of arsenic, which has been shown by Pattinson and Stead C Journal 

 of the Iron and Steel Institute,' 1888, Part I.) not to be so deleterious an ingredient 

 of steel as phosphorus. 



Practically inexhaustible beds of manganese ores, containing between 30 and 

 40 per cent, of manganese, with a large percentage of calcium carbonate, have also 

 been discovered in Chili ; but as yet only the richer ores, containing about 50 per 

 cent, of manganese, and upwards, can be profitably exported. 



Should the means of transport become cheaper in the future, these poorer ores 

 may possibly come into the market. 



On Barium SidpJiate in Water-hox Deposits from tlie Burlmm Coal- 

 mine Waters and in Nottingham Sandstone. By Professor Frank 

 Clowes, B.Sc. — See Section C, p. 594. 



5, The Manufacture of the Alloys of Aluminium in the Electric Furnace. 



By J. H. J. Dagger. 



Deville's method, modified in detail, is still the chief of the chemical processes 

 for the production of aluminium, and is dependent upon the cost of metallic 

 sodium. 



The greatest value of aluminium is, however, in its alloys, and the successful 

 application of the intense heat of the electric arc to their production on a commer- 

 cial scale marks a departure in electro-metallurgy of which we cannot over- 

 estimate the importance, rendering it possible to produce rich alloys of this metal 

 at half the cost of any other method, and so widening the field of their applica- 

 tion to an extent hitherto unknown. 



At the works of the Cowles Co., Lockport, N.Y., U.S.A., there are in opera- 

 tion fourteen furnaces, the electricity for wliich is generated by three dynamos, 

 capable of supplying a current of 3,000 to 3,200 amperes, and E.M.F. of 55 to 60 

 volts. 



These furnaces can produce 2,500 lbs. of aluminium bronze (10 per cent.), and 

 1,800 lbs. of ferro-aluminium (10 per cent.), or a total yield of 430 lbs. of con- 

 tained aluminium per 24 hours. 



The English works of the Company at Milton, Staffordshire, contain twelve 

 furnaces with a 500 horse-power dynamo, built by Messrs. Crompton, and said to 

 be the largest machine in England, and probably in the world; it furnishes a 

 current of 5,000 to C,000 amperes, with an E.M.F. of 50 to GO volts. 



