Care in the use of mercury
The usefulness of mercury for scientific purposes has already been mentioned on page 100. It does, however, give ofT a small quantity of odourless vapour which is poisonous if breathed for any length of time in a poorly ventilated room. Great care
should be taken not to spill it anywhere it is difficult to recover, for example, in cracks in the floor. All experiments with mercury should therefore be performed over a wooden or plastic tray.