Boyle-type anaesthetic machine, England, 1955-1965

A sphygmomanometer measures blood pressure. An inflatable cuff is placed around a person's arm. It is inflated to cut off the blood flow and then deflated to release it. Measurements are taken to record the pressure at each point, giving a numerical reading.

When the oxygen levels being provided by cylinders dropped below a certain pressure, a battery powered red light came on. If nitrous oxide gas was impacted, an audible whistle sounded. Original designs of the ‘Bosun’ oxygen warning device could be turned off accidentally, so many users were advised to remove the tap lever to prevent this from happening.

When first introduced warning devices, critics thought the devices might lull anaesthetists into a false sense of security, relying on machines rather than their observations and clinical knowledge.

Rotameters are also known as 'a float in a tube.' On the outisde is a scale. Inside is a float, which is denser than the liquid or gas it is measuring.

Known by brand name Flutothane, this device converted a liquid anaesthetic called halothane into a gas that could be inhaled.

Vaporising liquids into gases is one way that they can be given to patients. Ether was first used as an anaesthetic in 1846 during the removal of a tooth. By the 1960s it was replaced by more efficient anaesthetics.

An absorber made from soda lime removes carbon dioxide from a closed or semi-closed breathing system.

Henry Gaskin Boyle’s 1917 anaesthetic machine was the basis for a range of British anaesthetic machines. This example has meters for measuring gas flow, an oxygen failure warning device and a sphygmomanometer to measure blood pressure. Made by The British Oxygen Co Ltd, the machine was used at Airedale General Hospital, West Yorkshire, England.