The melting of small ice spheres and cones

The times of complete melting of small ice spheres in airstreams of controlled temperature, humidity and velocity were measured and compared with the values computed from theory. The theory, which allows for heat transfer to the ice particle by conduction through the air and by condensation upon its surface, agrees quite well with the observations if allowance is made for the heat content of the water retained by the particle during the melting process. The melting times of small ice cones of various shapes did not differ from those of spheres of equivalent volume by more than 10 per cent. It was demonstrated both theoretically and experimentally that an evaporating ice sphere will acquire the same surface temperature as the ice‐coated junction of a thermocouple psychrometer placed in the same airstream provided that the radiation and conduction errors of the latter are rendered negligible by good design.