68 SULPHUU. 



a gentle heat in close rooms, and thus forms Jlowws 

 of sulphur. 



If sulphur be exposed to heat it will soon fuse, 

 and, by continuing the fusion for some time, it will 

 become thick and tenacious. If worked between 

 the fingers under water in this state, it acquires a 

 consistency like wax, and may be employed for 

 taking impressions from seals or gems. This 

 change in the sulphur has been ascribed to oxyda- 

 tion; but the same effect takes place if the sulphur 

 be kept in fusion without access of air. 



Sulphur becomes electric by friction, and then 

 exhibits negative electricity. It is soluble in oils. 

 It does not combine with charcoal, but unites to 

 phosphorus by means of heat. Sulphur and iron 

 have a great attraction for each other. If a bar of 

 iron be heated to whiteness, and then touched with 

 a roll of sulphur, the two bodies combine and drop 

 down together in a fluid state, forming sulphuret of 

 iron. Sulphur also unites to potash and to soda, by 

 melting them together in a crucible : by this liver- 

 brown substances are formed, called sulphurets of 

 potash or of soda, which are soluble in water. 



Sulphur is a highly inflammable body, burning 

 with a pale blue flame. Put some threads, dipped 

 in sulphur, into a vessel floating in water. Set 

 fire to them, and cover the whole with an inverted 

 glass. The threads will continue to burn for some 

 time, and the receiver will be filled with a dense 

 white vapour. This vapour is the sulphurous acid, 

 formed by the union of the sulphur and the oxy- 

 gen during the combustion. It is absorbed by 

 the water which will ascend in the receiver. 



Let the whole then be left till the vessel is be- 

 come again transparent. If the water be exam- 



9 



