Ability to access this website does not imply a contract with David Knight or any of the other contributing authors. The information accessible from this website is offered without warranty of any kind, and I reserve the right to withdraw the service without notice. While every effort has been made to ensure that the information given here is correct, no liability is accepted for accident, injury, loss, inconvenience or disappointment resulting from its use.

David W Knight

A sign seen by people entering the town of Ottery St Mary on tar barrels night relates to the nature of the evening's events; but it is also of general existential relevance.

Some of the experiments described on this website are dangerous. Although safety issues are typically discussed as they arise; it is assumed that anyone attempting to repeat any of the procedures described will be fully conversant with the relevant safe working practices.

Some dangers are not immediately obvious
1) Skin and (particularly) eyes must not be exposed to hard UV light (such as is produced by silica-walled mercury discharge tubes).
2) Glass vacuum equipment must never be operated without safety glasses. Unless provided with an implosion shield, large glass vacuum chambers should not be opeated without a full face shield and full body covering.
3) Audiences, bystanders, and passers-by require the same protection as the experimenter.