NATURAL SCIENCES OP PHILADELPHIA. 15 



sodium, have fully demonstrated that it is the most economical mode by which 



to produce this metal. Theoretically it requires — 



3-86 Chlorine, at 6 cents per pound, . . . -23 16-100 



1-86 Alumina, at 3 " " 05 58-100 



5-68 Carbonate of Soda, at 4 cents per pound, . -22 72-100 



Total, -51 46-100 



Making for the materials for manufacturing one pound of aluminium, estimated 

 at the market prices, 51^ cents. Practically it requires — 



16 lbs. of the double chloride of aluminium and sodium, at 8 cts. per lb., $1 28 

 2| lbs. metallic sodium, at about 25 cents per lb., .... 70 



Flux aud cost of reduction, 2 02 



Total, $4 00 



By manufacturing on a larger scale, and by using the slag as a flux instead of 

 employing fresh material, the lowest cost will be reduced to the following : 

 10 lbs. of double chloride of aluminium and sodium, at 4J cents per lb., $0 45 

 2\ lbs. of sodium, at 14 cents per lb., ....... 35 



Cost of reduction, 20 



Total, $1 00 



It is seen that the actual cost of one pound of aluminium, when manufactured 

 extensively, will be about double the theoretical cost as before estimated, (fifty- 

 one cents.) 



For the production of aluminium are used clay, salt, sulphur, manganese, 

 lime and fluor spar, materials which are very abundant and cheap ; all that is 

 now required is practical experience, to reduce the price of the metal still nearer 

 to the price of the raw materials, as has been before stated. The history of the 

 useful arts coutains numerous instances that, where skill and perfection of ap- 

 paratus are required, difficulties are speedily overcome. 



The density of aluminium when moulded is 2-56. The density of aluminium 

 when rolled is 2-67. In equal weight with silver it is four times more volumi- 

 nous. In equal weights with copper, bronze, brass and German silver, it pos- 

 sesses from three to three and a half times greater volume. In equal volumes 

 with the above metals and alloys it possesses greater rigidity. 



Mention has already been made of a very important property of aluminium 

 when pure ; that is to resist oxidation, a property which it possesses to a greater 

 degree than the other metals. 



Aluminium is not acted upon by nitric acid, hydrosulphuric acid, or by the or- 

 ganic acids ; slightly by sulphuric acid. It is but little affected by fusion with 

 sulphur ; mustard is found to act upon it slightly. Its true solvent is hydro- 

 chloric acid. 



When we compare it in these respects with those metals, which are acted 

 upon by most of these acids giving salts, which are more or less poisonous, the 

 comparison is favorable to aluminium, as its salts, if formed, are innocuous. 



According to M. C. Tissier, aluminium is not changed by a solution of nitrate 

 or sulphate of copper, but it is dissolved by a solution of chloride of copper with 

 the separation of metallic copper. It is attacked, however, by a solution of ni- 

 trate or sulphate of copper when it contains chloride of sodium, and this proves 

 that chloride of copper is formed by the presence of the chloride of sodium. 

 Aluminium is not attacked by an aqueous solution of alum, or by one of chlo- 

 ride of sodium, but a mixture of the two dissolves it with an evolution of hydro- 

 gen, aud this proves that chloride of aluminium is contained in the mixture. 



Wheatstone long since showed that aluminium was as strongly electro-nega- 

 tive as platinum. Its sonorous qualities are very great, like tlaat of crystal. 

 Various are the uses which can be made of the aluminium and of its alloys with 

 silver and copper. All the purposes for which it could be advantageously em- 

 ployed in virtue of its peculiar properties, of not tarnishing by exposure to at- 

 mospheric agencies, aud its lightness combined with its extraordinary strength, 



1857.] 



