The riot act:

• You must never touch any button or knob on the electron microscope without the demonstrator's permission.
• If you turn some knobs on the electron microscope, you can cause enormous and very expensive damage.
• Never do anything to the vacuum system unless the demonstrator has given you explicit permission.
• Never attempt to switch on the microscope if there has been a power cut.
• If in any doubt about any knob or control, always ask the demonstrator before you touch it.

Copyright J M Rodenburg