II. On attraction and repulsion of bubbles by heat

In my first paper “On the presence of Liquid Carbon Dioxide in Mineral Cavities” (‘Journal of the Chemical Society,' February 1876), I mentioned having noticed a remarkable repulsion of the bubbles in fluid-avities when they were approached by a heated body. I at first regarded these movements as similar to those observed by Mr. Sang and Dr. Hunter (Proceedings of the Royal Society of Edinburgh, 1872-73, p. 126) in cavities of Iceland spar; but with reference to the position of the source of heat, I have since found that they occurred in quite the reverse direction. The motion noticed by Mr. Sang was a repulsion of the liquid; that which I recorded was a repulsion of the gas by the heated body. Here I may as well say that this refers to the real and not the apparent direction of the motion as seen under the microscope.