On the Viscosity of Sulphur

A great amount of work has been done on the composition and properties of liquid sulphur by Prof. Alexander Smith and his collaborators, mainly at the University of Chicago. The general conclusions arrived at by them may be briefly stated as follows: Ordinary liquid S consists of two modifications of sulphur known as Sλ and Sμ in liquid S varies with the temperature, but provided the temperature has been kept constant for a sufficient length of time the percentage composition at any particular temperature is always the same, though various impurities such as SO2, NH3, H2SO4 may retard or accelerate the attainment of a state of equilibrium. The percentages of Sμ, when equilibrium has been attained, have been given by Smith and Holmes and Carson on a continuous curve from 120° C. to 440° C., and from this curve it seems that the Sμ varies from 3·75 per cent. at 120° C. to 34 per cent. at 440° C. A sharp rise in the percentage of Sμ takes place at about 160° C., corresponding with the increased viscosity of S about the temperature. An apparent exception to the general rule of impurities was found for iodine with which higher percentages of Sμ were obtained. Smith and his collaborators do not claim that the percentages given by them are the actual percentages in liquid S, as in the process of chilling some Sμ may revert to Sλ, and thus the percentages of Sμ may be too low. By chilling a stream of burning S they found a percentage of 51 per cent., which would seem to indicate that the value 34 per cent. at the boiling point as found by ordinary chilling was too low.