CHEMICAL SCIENCE. 177 



thallium included, must be halved to make them fit Dulong and Petit's 

 law concerning the relation of atomic weight to specific heat. The 

 commissioners further observe that the alkaline metal series contains 

 one, lithium, whose atomic weight is so light as to place it near hy- 

 drogen, and another, thallium, so heavy as to rank with bismuth 

 whose equivalent is the heaviest known." 



Thallium in American Furnace Products. Mr. TV. T. Eoepper, in 

 a communication published in Sttliman's Journal, states that he has 

 detected thallium in the dust deposited on the boilers of the Bethlehem 

 Iron Works, of Penn., and in similar dust from a furnace on the Lehigh. 

 lie considers it not unlikely " that it is a common product of the an- 

 thracite furnaces, and is perhaps derived from the pyrites accompany- 

 ing the coal." Mr. Roepper states, however, that he has not been able 

 as yet to detect it in the ashes of anthracite from a common stove. 



PREPARATION OF MAGNESIUM. 



At a recent meeting at the Royal Institution, London, Mr. Teget- 

 meier exhibited a mass of magnesium which had been prepared by Mr. 

 E. Sonstadt, who has recently patented a process whereby this metal 

 may be obtained in quantity. Mr. Faraday called the attention of the 

 members to the remarkable properties of this metal. Its whiteness, 

 resembling that of silver, and high metallic brilliancy, were shown by 

 means of the electric lamp. A wire of the metal was ignited in the 

 flame of a candle, when it burnt with a white light of such dazzling in- 

 tensity as totally to obscure the ordinary illuminating agents, such as 

 gas and candles, and to rival the brilliancy of the electric light. Mr. 

 Faraday stated that notwithstanding its strong attraction for oxygen, 

 it was preserved from change, when in a mass, by the thin film of ox- 

 ide covering and protecting the exterior surface from the exposure of 

 the air. 



Mr. Sonstadt's process for preparing magnesium on a manufacturing 

 scale consists in decomposing a mixture of fused chlorides of magnesium 

 and sodium by means of metallic sodium, and in the employment of 

 iron vessels to effect the decomposition. It is found that the magnesium 

 acts on the silica of earthenware crucibles, decomposing it, and uniting 

 with the silicon ; nor can platinum crucibles be employed, as the mag- 

 nesium alloys with that metal, causing it to become fusible at a moder- 

 ate temperature. The chloride of magnesium employed is best obtained 

 from the mother liquor, left after evaporating sea-water for its salt. 

 Mr. Faraday stated that as every ton of sea-water contained above 

 two pounds of magnesium, in the form of chloride, the entire ocean 

 would contain 160,000 cubic miles of magnesium. This would form a 

 solid block fifty-four miles cube. The specific gravity of magnesium 

 is 1.75, resembling in its lightness the analogous metal aluminum. 

 Now that magnesium is capable of being obtained quickly, there is no 

 doubt that important applications of its singular properties will present 

 themselves. The metallic bases of the earths are in so much greater 

 abundance than the ordinary metals, that any attempt to isolate them 

 for economic and practical purposes must be regarded with great inter- 

 est, as bearing strongly on the advance of not only the scientific arts, 

 but also of those having reference to daily life and advancing civil- 

 ization. 



