chamber 6 permitting the pressurization and heating of the gas used a liquid drop can either be placed in direct contact with the wall and raised by forcing a gaseous mass through the wall or a solid mass can be used which is raised by a gaseous film and then melted in the particular case shown in fig1 a parallelepiped of approximately 10 g of solid silicon is placed in the centre of a graphite plate 4 with a 32 open porosity the plate thickness being approximately 3 mm the solid silicon block is firstly raised by diffusing the helium through the wall 4 the assembly is placed in a resistance oven which induces no electromagnetic force on the silicon mass heating is started up and is increased until the silicon melts the latter is collected in the form of drops essentially under the action of the high surface tension of the liquid silicon to maintain drop 2 at the same point on the outer surface of plate 4 the latter is given a slightly concave shape thus as the weight of the drop is balanced by the pressure of the gaseous film if no restoring force maintains it it acquires a considerable mobility under the effect of minimal uncontrolled forces thus a slightly concave wall shape is used to prevent an accidental displacement of the drop however in certain cases.