Experiment on a one-way flow of a rarefied gas through a straight circular pipe without average temperature and pressure gradients

It is demonstrated experimentally that a one-way flow of a slightly rarefied gas is induced in a circular straight pipe of a uniform diameter with its two ends being kept at an equal temperature and pressure by heating the middle part along the pipe and by putting up a shelf or shelves inside of a half part of the pipe on one side of the heater. The experiment is done in a small vacuum chamber of a glass bell jar, and the flow is detected by a small windmill. A one-way flow is induced from the part of the pipe with a shelf or shelves to that without it or them. The mechanism of the flow is explained by the difference of dependence on the cross sectional area between the thermal transpiration and Poiseuille flow.