D. CHEMISTRY AND METALLURGY. 109 



a successful result until after the supposed refuse substance, 

 containing magnesic salts, was pierced. The entire deposit 

 is upward of 1300 feet thick, and consists of four groups or 

 regions. The lowest is the rock salt ; the next is the poly- 

 halite group, in which common salt predominates, but mixed 

 with magnesium, calcium, and potassium. The third is called 

 the kieserite region, consisting principally of an abnormal 

 hydrated magnesic sulphate. The fourth, the Abraum salt, 

 the most interesting of the whole, chiefly consists of a double 

 chloride of potassium and magnesium, which occurs both of 

 a white and red color, and contains traces of other salts, and 

 includes several minerals, such as sylvin, kainite, tachydrite, 

 stassfurtite, etc. From these various substances, principally 

 from the Abraum salts, an immense variety of products is 

 now obtained, the most important being potassic chloride. 

 Besides this, there is a considerable quantity of chloride of 

 magnesium and of bromine, of which latter substance about 

 30 tons are manufactured annually. Some of the other prod- 

 ucts are saltpetre and carbonate of soda, the latter being 

 made in large quantities for use in soap-boiling and bleach- 

 ing, as well as in glass and alum manufactories. A large 

 proportion of the bleaching salts are used in the preparation 

 of manures, made by adding them to phosphatic or other ma- 

 nures obtained elsewhere; of such manures more than 270,000 

 tons were produced in 1869. 13 A, July 15, 1872, 269. 



COMBUSTIBILITY OF IROX. 



An interesting experiment to demonstrate the combustibil- 

 ity of iron has lately been devised by Professor Magnus, of 

 Berlin. He takes a straight bar-magnet of some power, and 

 sprinkles iron filings on one of its poles. These filings arrange 

 themselves in accordance with the lines of magnetic force, 

 and however closely they may appear to be packed, of course 

 no two of the metallic filaments are parallel, and consequent- 

 ly a certain portion of air is inclosed, as in a metallic sponge. 

 The flame of a spirit-lamp or gas-burner readily ignites the 

 finely-divided iron, and it continues to burn most brilliantly 

 for a considerable time. 



If the experimenter stands on a little elevation, and waves 

 the magnet to and fro while burning, a most magnificent rain 

 of fire is produced. The experiment was first exhibited in 



