670 Transactions of the American Institute. 



saud tons of spiegeleisen, and the demand for this material is con- 

 stantly increasing. The fact that the small district in the vicinity 

 of the town of Siegen, in Prussia, has, up to the present moment, 

 held a monopoly with regard to the English market for the supply 

 of this article, is sufficiently important to make a careful examina- 

 tion of all spiegeleisen produced in different countries and locali- 

 ties, and now collected in the Paris Exposition, very desirable; 

 principally with a view of getting acquainted with such places and 

 works as may, at some future time, be in a position to supply the 

 demands of the British market, if from natural or accidental causes 

 the present sources of spiegeleisen should fail. After reviewing 

 the localities of spathic ore in Austria, Hungary, Prussia, Russia, 

 France and Italy, the writer alludes to the American spiegeleisen, 

 shown by the New Jersey Zinc Company, made from franklinite, 

 which is admitted to be very fine, and the intimation is thrown out 

 that it is not impossible that America may very shortly be able to 

 produce a supply of spiegeleisen exceeding the demand of British 

 steel makers, and at a price which will make them more independ- 

 ent of the iron masters of the Siegen district. The amount of man- 

 ganese in the spiegel of Siegen is stated to be from nine to ten per 

 cent. About fifteen thousand tons are annually produced, which 

 commands, at the place of manufacture, from twenty-five to thirty 

 dollars per ton. 



SENSITIVE DRY PLATES. 



A French photographic journal recommends the use of tannate 

 of soda instead of tannic acid, in order to increase the sensitiveness 

 of dry plates. 



TO SOLDER ALUMINIUM BRONZE. 



Mr. Hulot has found that equal quantities of common solder and 

 zinc amalgam form a mixture by which aluminium bronze may be 

 readily united. The solder is still more effective if alloyed with 

 twice its weight of tin. 



TUNGSTEN STEEL. 



M. Le Guen, of France, has succeeded in making tungsten or. 

 wolfram steel by the Bessemer process. He simply substitutes an 

 ore containing tungsten for the spiegeleisen iron of Prussia, which 

 contains manganese. To three thousand two hundred kilograms 

 of the gray iron known to make the best steel, is added four hun- 

 dred kilograms of the tungsten ore. The steel thus obtained by 

 the Bessemer process is well laminated, and capable of being tem- 



