Fluidity of Sulphur at Common Temperatures. [1826. 



reason to believe that water or its vapour confer volatility, even 

 in the slightest degree, upon those substances which when alone 

 have their limits of vaporization at temperatures above ordinary 

 occurrence, and that consequently natural evaporation can 

 produce no effects of this kind in the atmosphere. 



It would also appear that nitrate of ammonia, corrosive sub- 

 limate, oxalic acid, and perhaps oxalate of ammonia, are sub- 

 stances which evolve vapour at common temperatures. 



Royal Institution) Aug. 30, 1830. 



Fluidity of Sulphur at Common Temperatures*. 



HAVING placed a Florence flask containing sulphur upon a hot 

 sand-bath, it was left to itself. Next morning, the bath being 

 cold, it was found that the flask had broken, and in consequence 

 of the sulphur running out, nearly the whole of it had disap- 

 peared. The flask being broken open, was examined, and 

 was found lined with a sulphur dew, consisting of large and 

 small globules intermixed. The greater number of these, 

 perhaps two-thirds, were in the usual opake solid state ; the 

 remainder were fluid, although the temperature had been 

 for some hours that of the atmosphere. On touching one of 

 these drops, it immediately became solid, crystalline, and 

 opake, assuming the ordinary state of sulphur, and perfectly 

 resembling the others in appearance. This took place very 

 rapidly, so that it was hardly possible to apply a wire or other 

 body to the drops quick enough to derange the form before 

 solidity had been acquired ; by quick motion, however, it might 

 be effected, and by passing the finger over them, a sort of 

 smear could be produced. Whether touched by metal, glass, 

 wood, or the skin, the change seemed equally rapid ; but it 

 appeared to require actual contact ; no vibration of the glass 

 on which the globules lay rendered them solid, and many of 

 them were retained for a week in their fluid state. This state 

 of the sulphur appears evidently to be analogous to that of 

 water cooled whilst quiescent below its freezing-point. The 

 same property is also exhibited by some other bodies, but I 

 believe no instance is known where the difference between the 



* Quarterly Journal of Science, xxi. 392. 



