PROCEEDINGS 



PHILOSOPHICAL SOCIETY OF GLASGOW. 



FORTY'FIRST SESSION, 1842-43. 



CONTENTS. 



Dr. Thomson on the Melting Points of Alloys of Lead, Tin, Bismuth, and Zinc, 77 



Notices of some recent Botanical Facts, 82 



Mr. George Thomson on Blast Furnaces, 84 



I4:th December, 1842, — The President in the Chair. 



Messrs. Andrew Stein and William Graham were admitted Mem- 

 bers of the Society. Mr. Liddell suggested that, to avoid the Christ- 

 mas week, the next meeting of the Society should be postponed till 

 the 4th January. The Vice-President having taken the Chair, the 

 following papers were read: — 



XXII. — On the Melting Points of Alloys of Lead, Tin, Bismuth, and 

 Zinc. By Thomas Thomson, M.D., F.R.S., Begins Professor of 

 Chemistry. 



As the first three of these metals melt at temperatures below the boil- 

 ing point of mercury, the determination of the melting points of their 

 alloys is attended with little difficulty. Zinc, according to the experi- 

 ments of Daniel, melts at 773°, which is above the range of a mercurial 

 thermometer; but when tin is alloyed with it the melting point is 

 considerably under 662°, which is the degree of Fahrenheit's thermo- 

 meter at which mercury boils. 



Though these experiments are of easy execution, I am not aware of 

 any person having tried them, except Kupfer in 1829, and Rudberg 

 in 1831. Rudboi'g made a careful examination of the melting point 

 of alloys of tin and lead, tin and bismuth, zinc and tin. But he 

 informs us that his thermometer was inaccurate, while he forgets to 

 state tlio amount of the inaccuracy. So that we cannot consider the 

 points which he has stated in his tables as the true melting points of 



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