Glassware for distilling chemicals. This apparatus is known as a Graham condenser, and is used to purify chemicals through distillation. It consists of a coiled glass tube enclosed in an open-ended glass envelope. Coolant, such as tap water, can be fed into the envelope, while hot vapours flow through the coil. The vapours cool and condense, and can be collected as liquid. Alternatively, to maximise cooling capability, the coolant can be fed into the coil and the vapours into the envelope.