Some Laboratory Applications of the Low Friction Properties of the Dry Hypodermic Syringe

The principle of rotating either the barrel or plunger of a dry hypodermic syringe to produce a low friction gas sealed bearing is described. The application of this principle to accurate measurement of gas volume at very low pressure heads, and further applications to other instruments operating at low pressure heads is indicated. Horizontal motion of the plunger was produced in a rotating syringe barrel with pressures as low as 0.6 dynes per cm2.