296 Proceedings of Philosophical Societies. [April, 



sumes three cubic feet of gas in an hour, when the flame is 2^ inches high, and 

 prodnces a light equal in intensity to four tallow candles, eight in a pound. 



An argand burner, seven-eighths of an inch in diameter, perforated with 18 holes 

 one thirty-second of an inch in diameter, consumes, when the Uaine of the gas is 

 three inches liigh, four cubic feet of gas in an hour, and produces a light equal in 

 intensity to six tallow candles eight in the pound. 



When the flame obtained by these kind of burners rises to a greater height than 

 what has been slated, the combustion of the gas is imperfect, the intensity of the 

 light becomes diminished, and tliere is a waste of gas. The same holds good with 

 regard to the size of the holes from which the gas issues. If the holes be made 

 larger than one twenty-fifth part of an inch in this kind of burners, the g.is isnot 

 completely burned, and its illuminating power decreases. 



The height of tlie glass ivhich surrounds the flame should never be less than five 

 inches, and the interval for the current of air within and without the flame ought to 

 bear theu^ual proportion adopted for the combustion of oil in the common argand 

 lamps of similar diameters. 



We have likewise an account of the mode of obtaining gas 

 from coal tar, and gas from oil. The processes for distiUing 

 coal oil, and making carbonate and muriate of ammonia from the 

 aramoniacal liquor, are also given. 



Article IX. 



Proceedings of Philosophical Societies. 



ROYAL SOCIETY. 



On account of the death of the King and the Duke of Kent 

 there, was no meeting of the Society from Jan. 20 till Feb. 17. 



Fei). 17. — At this meeting, Mr. E. Davy's paper, on some Com- 

 binations of Platinum, was concluded. The principal object of 

 this paper was to describe a peculiar compound of platinum 

 obtained from the sulphate by the agency of alcohol. Sulphate 

 of platinum was boiled in alcohol; a substance was precipitated; 

 which, when dry, w as black, insoluble in water, and unaltered by 

 exposure to air. When heated, it was reduced with a shght 

 explosion. It was insoluble in nitric, sulphuric, and phosphoric 

 acids, but dissolved slowly in the muriatic acid. Wheir steeped 

 in ammonia, it acquired fulminating properties. Alcohol imme- 

 diately decomposed it, as was shown by slightly moistening it 

 with that fluid ; such a heat being produced as to ignite the 

 separated platinum. Hence the authtir recommended it as a 

 means for procuring an instantaneous light. 



When submitted to analysis, it appeared to consist almost 

 entirely of platinum, with a little oxygen, and the elements of 

 nitrous acid. It also contained a small proportion of carbon, 

 which the author considered as accidental. The nitrous acid 

 w^as supposed by the author to be derived from the sulphate of 

 platinum, this being formed from the sulphuret of platinum by 

 the agency of nitric acid. 



