Published online by Cambridge University Press: 15 September 2014
A method for determining the boiling-points of solids as well as liquids, such that little material is required, and only constant, easily reproducible conditions are involved, is much needed. None of these qualities is possessed by the distilling flask method.
The apparatus suggested consists of a bulblet with a bent capillary not less than 1 mm. in diameter. This is attached to a thermometer and suspended in a beaker (fig. 1). The latter contains water (for substances boiling below 100°), sulphuric acid (up to 200°), melted paraffin (up to 280°), or a mixture of sodium and potassium nitrates (45·5, 54·5 parts) for use from 220° upwards. A stirrer is provided.
page 434 note * We are indebted to Mr F. B. Plummer for making a series of determinations of the specific gravities of the bath-liquids at various temperatures. The following formulæ summarise the results, and give values correct to the second decimal place within the limits of temperature specified:—
Sulphuric acid (92·75 per cent., 30–200°), 1·818−0·000906(t−30).
Paraffin (m.–p. 53°, 60−230°), 0·778−0·000612(t−60).
Two nitrates (230−390·), 1·968−0·00075(t−230).
page 435 note * Young, , Stoichiometry (London, 1908), 264.Google Scholar