CHEMICAL SCIENCE. 217 



begins to figure as an electro-chemical agent in a no less remarkable manner. 

 The director of the galvano-plastic department of the Mint, M. Hulot, sub- 

 mitted to the Academy, through M. Dumas, some assays in which this metal 

 was substituted for platina as an electro-negative element in the piles to a 

 single liquid. M. Hulot has succeeded, not without great difficulty, in rolling 

 perfectly and without loss, an ingot of aluminum of thirty and some gram's, pro- 

 cured from one of the first meltings of this metal obtained by M. Rousseau less 

 white than at first, and containing traces of iron and silicium. A connection 

 of aluminum and zinc amalgamated for a long time, charged with water acid- 

 ulated with a twentieth of sulphuric acid at 66, disengaged during the first 

 hours considerable hydrogen, and produced a current equal, if not superior, 

 to that of a connection of platina and zinc excited to the same degree. The 

 author asserts that the nest day the electro-motive force of the pile was re- 

 duced nearly one quarter ; but he remarks that it suffices to immerge the 

 aluminum in nitric acid, or still better, as it appears, in sulphuric acid as it 

 is expedient to effect it at once to give to the circle its first force. 



" As aluminum is nine tunes lighter than platina, and presents also a surface 

 nine times more extended than the latter metal, with an equal thickness, its 

 substitution for platina should be productive of real advantages, above all now 

 that its price has become very accessible. The aluminum here spoken of is 

 very difficult to forge. In order to roll it, it has been found necessary to an- 

 neal it at each pass. By deposing copper electro-chemically on a plate of 

 aluminum, they have succeeded, by the aid of rollers, in reducing it to very 

 thin plates. Hard aluminum acquires by annealing an inflexibility which 

 would make it of great use in the suspension of all kinds of scales for assays 

 or analyses. This metal is so light that, the weights of the system being the 

 same, the arms of the beam can be elongated a great deal, and long blades 

 can be placed even ori the extreme points of suspension, as on the center of 

 oscillation. The author does not doubt that in weighing 20 grammes, the 

 sensibility of the balance would not rise a half-millionth." 



The price of aluidkmm a short time since in France was about the rate of 

 gold. M. Dumas, in a recent communication to the Academy, stated that, 

 owing to recent discoveries reducing the expense of extracting it, the cost of 

 production was now about one hundred times less ; and M. Balard, another 

 member, stated that there was little doubt that the effect of competition in 

 its manufacture, together with the advantage of throwing it open to the in- 

 dustrial resources of the world, would be to -reduce the price as low as five 

 francs the kilogram, or about forty cents a pound. 



This important result is mainly attributable to the facility with which we 

 are now able to procure pure sodium in abundance, which is the active agent 

 for the revivication of aluminum, and which was at one time very expensive. 

 M. Dumas observes that the generalization of the procedure of M. Deville, the 

 application of chlorine to the extraction of metals, forms a new era in metal- 

 lurgy. Among the many remarkable qualities of aluminum, such as its re- 

 sistance to oxydation, either in the air or by acids, its hardness, its wonderful 

 lightness, its malleableness, the facility of molding it, etc.. M. Dumas mentions 

 another, its sonoSity. An ingot was suspended by a string, and being lightly 



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