208 ANNUAL OF SCIENTIFIC DISCOVERY. 



Swedish iron, whenever it presented the peculiarity of what is 

 technically termed " cold short." The process adopted was the 

 following : The pig-iron, weighing about three grams, and reduced 

 to small pieces, was dissolved in diluted nitric acid, the solution 

 evaporated to dryness, the dry mass heated strongly with free ac- 

 cess of air, in order to destroy all carbon. After heating, the dry 

 mass was triturated and mingled with six times its weight of soda, a 

 little chlorate of potassa, and a little silica, and smelted as long as any 

 gas was disengaged. The smelted mass was exhausted by boiling 

 water, and digested for some hours. The solution was filtered, the 

 undissolved residue washed with hot water, containing a small quantity 

 of chloride of ammonium. The solution was evaporated to dryness, 

 and the dry mass treated with hydrochloric acid and dissolved in water. 

 After filtration, the solution was neutralized, and the phosphate of 

 lime was precipitated in a closed vessel by a solution of chloride of 

 calcium with ammonia. Dr. Percy spoke of the importance of this 

 inquiry, particularly in such a district as Birmingham. He then 

 instanced many of the peculiarities of the Staifordshire iron, which 

 contains phosphorus ; and spoke of the peculiarity of the Berlin iron, 

 which is so singularly fluid in casting, as being probably due to some 

 such combination. Dr. Ronalds, Dr. Miller, and Mr. R. Phillips, 

 confirmed the fact of the general presence of phosphorus in cast- 

 iron. Athenceum, Sept. 15. 



MERCURY IN HERMETICALLY-SEALED GLASS VESSELS. 



THE distinguished Prof. Oersted has discovered that a change takes 

 place in mercury kept in hermetically-sealed glass vessels, but that it 

 is very slow and not perceptible for years. He had observed it twenty 

 years ago in a glass bulb. He first took up the subject in 1828, 

 experimenting with four bulbs, two of white and two of green glass, 

 carefully weighed, in order to detect any portion of air that might be 

 admitted through the pores or fissures of the glass. The weight, 

 however, remained unaltered. In July, 1839, a small change was 

 visible. At first a feeble ring of yellow powder adhering to the glass 

 was observed, where the mercury had been a long time in contact 

 with it. And again, in a new place, under similar circumstances, a 

 new ring was formed, and so on. The surface itself, upon which the 

 mercury had rested some time, had a thin covering of yellow adherent 

 powder. In the course of years the yellow powder became black, the 

 mercury had lost a great deal of its fluidity, and it adhered slightly to 

 the glass. The order in which the two colors follow each other indi- 

 cates that they are not produced by oxidation. In the green bulbs no 

 change was visible. In 1845, Prof. Oersted procured twelve bulbs, 

 six of which should contain, beside the mercury, atmospheric air, the 

 air of the other six being expelled by boiling mercury ; three of each 

 series were white, and three green glasses. In July, 1847, there 

 was no sensible change in the series, w r here air was mixed with the 

 mercury, but in the other, where the air had been exhausted, change 

 had taken place in all but one. Rarefaction of the air had no con- 



