As I have been partly to blame for the delay in the publication of the observations described in the preceding paper by Mr. N. Eumorfopoulos, it seems tight that I should make a brief statement, by way of apology, with regard to the object of the work and the causes which have led to the delay. The determination of the boiling-point of sulphur by Mr. E. H. Griffiths and myself in 1890 was made with the same air thermometer as that employed in my original experiments of 1887, and gave the same value for the difference-coefficient of the platinum thermometer. The result depended, however, on the scale of the constant-pressure air thermometer, and the correction for the expansion of the bulb was deduced from observations of the linear expansion over the range 0° to 500°C. of a piece of glass tube from which the bulb was made. Some uncertainty was introduced also by changes in the volume of the bulb at a temperature of 450°C.