A gas that sinks in a liquid-the first helium experiment published by Kamerlingh Onnes.

The year 1906 was a year of many remarkable achievements in the laboratory of Kamerlingh Onnes and his staff. They put into operation a hydrogen liquefier producing 4 l h(-1), followed by a liquid-hydrogen cryostat for work below 21 K. They prepared their first sample of 2 l of helium gas.