CHEMICAL SCIENCE. 203 



obtained by electrolysis, is upon a fresh fracture sometimes faintly 

 crystalline in large plates, at others fine grained ; in the first case, it 

 is silver-white and very brilliant, in the last more bluish gray and 

 without lustre. Its hardness is nearly that of calc-spar. It fuses at 

 a moderate heat ; in dry air it is wholly unchangeable, and does not 

 lose its lustre ; in moist air it soon becomes covered with a coating of 

 magnesia. Heated to whiteness in the air, it takes fire and burns 

 with an intense white light ; the evolution of light by combustion in 

 oxygen is of unusual intensity -- about 500 times that of a wax can- 

 dle. The metal decomposes pure cold water very slowly, acidulated 

 water rapidly. Thrown upon aqueous muriatic acid the metal 

 instantly ignites. Concentrated sulphuric acid dissolves it slowly ; a 

 mixture of nitric and sulphuric acids has no action in the cold. The 

 density of magnesium was found to be 1.7430 at 5 Centigrade. 

 Calculated from this, the atomic volume of magnesium is 86, or 

 exactlv double that of nickel. The metal, as obtained bv electrolvsis, 



* mm 



may easily be filed, bored, sawed, or somewhat flattened by hammer- 

 ing, but is hardly more ductile than zinc, at ordinary temperatures. 

 The magnesium obtained by means of potassium, contains a small 

 quantity of that metal, and is ductile ; that reduced by electrolysis, 

 almost always contains traces of aluminum and silicon. Ann. der 

 Ckemie und Pharmacie, Ixxxii. 137. 



TITANIUM AND ZIRCONIUM IN MINERAL WATERS. 



DR. MAZADE, of Yalence, states that he has detected in the mine- 

 ral waters of Neyrac, France, both titanium and zirconia. He had 

 previously announced his having found in the same waters, molybde- 

 num, tin, tungsten, tantalum, cerium, yttrium, glucinium, nickel, and 

 cobalt. L'Institut, No. 964. 



ON THE PASSIVE STATE OF METEORIC IRON. 



WOHLER states, that he has observed the curious fact, that the 

 greater portion of the meteoric iron he has had an opportunity of 

 examining, is in the so called passive state, that is to say, it does not 

 reduce the copper from a solution of the neutral sulphate of copper, 

 but remains bright and uncoppered therein. But if touched in the 

 solution with a piece of common iron, the reduction of the copper 

 commences immediately upon the meteoric iron. It also becomes 

 active instantaneously on the addition of a drop of acid to the solution 

 of copper ; but if the reduced copper be filed away, the new surface 

 is again passive. I convinced myself by experiments on meteoric 

 iron, which had never been in contact with nitric acid, and neverthe- 

 less was passive, that this state could jaot have been produced by the 

 corrosion of the surface by the acid, "for the production of the *Wid- 

 niannstattean figures. I thought first that this deportment might be 

 employed as a means of distinguishing true meteoric iron ; but it soon 

 appeared that some undoubtedly genuine meteoric iron was not iii this 

 18* 



