16 PROCEEDINGS OF THE ACADEMY OF 



would be far too tedious to enumerate. A few instances only will suffice of its 

 adaptability for philosophical apparatus, for all articles for table, for service 

 and ornament, for kitchen utensils, for the works of clocks and even watches, 

 for trappings of harness, for plate and door knobs, keys, &c. Its sonorous quali- 

 ties render it valuable for making bells. In the galvano-plastic arts it replaces 

 platinum. 



Aluminium is most easily soldered with its own alloys. The alloys most con- 

 venient are those with silver, zinc or tin, their point of fusion being below that 

 of aluminium. The soldering may be done by means of a spirit lamp, and with- 

 out any previous cleaning. 



Pure aluminium can be easily distinguished from impure by its greater white- 

 ness, its indistinct traces of crystallization ; occasionally one or two well- 

 defined hexagons can be recognized on the surface of the ingots. The impure 

 has a bluish tint like zinc, and if the entire surface is not crystalline, the upper 

 surface is always more so than in pure aluminium; the form of the crystals is 

 also quite different. 



In giving the theoretical proportion of material employed in the manufacture 

 of aluminium, the relative cheapness of its production, its properties and strength 

 when comparing it bulk for bulk with other metals, it is desired to demonstrate 

 its valuable properties and uses, also to guard against the fictitious reports so 

 current of its excessive cheapness. 



Note. — The experiment of Sir H. Davy should be mentioned in the early pro- 

 duction of this metal ; he endeavored to produce it by passing the vapor of po- 

 tassium over alumina at a white heat ; he obtained only small grey particles 

 interspersed with aluminate of potash. 



[Jan. 



