THE FLOW AND VISCOSITY OF LIQUID HELIUM

Abstract
Experiments on the flow of liquid helium through glass capillaries ranging in diameter from 0.025 cm. to 0.0036 cm., and with lengths varying from 2 cm. to 26 cm. were carried out. Normal laminar flow was obtained for He I with a viscosity of the order of 10−5 c.g.s. units. For He II it was found that the flow could be expressed as the sum of a laminar flow plus an additional pressure-independent flow. The laminar portion, which obeyed Poiseuille's law, gave a viscosity of the order of 10−3 c.g.s. units. The pressure-independent portion appears to be partially due to "creep" over the top of the reservoir, but there still remains an additional pressure-independent flow through the capillaries. This additional flow depends among other things on the intensity of illumination and is evidently connected with the "fountain" effect.