:Presumably something to do with the McLeod gauge.
2.
The design of a McLeod gauge is somewhat similar to a that of a mercury.
3.
These indirect measurements must be calibrated via a direct measurement, most commonly a McLeod gauge.
4.
For this reason, McLeod gauges continue to be used as a calibration standard for electronic gauges.
5.
McLeod gauges were once commonly found attached to equipment that operates under vacuum, such as a lyophilizer.
6.
These indirect measurements must be calibrated to SI units via a direct measurement, most commonly a McLeod gauge.
7.
A cold trap may be used in conjunction with a McLeod gauge to condense these vapors before they enter the gauge.
8.
In 1874 he published a paper with a new and innovative vacuum gauge, this is known as the McLeod gauge.
9.
An important variation is the McLeod gauge which isolates a known volume of vacuum and compresses it to multiply the height variation of the liquid column.
10.
A "'McLeod gauge "'is a scientific instrument used to measure very low pressures, down to 10 " 6 Torr.