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Cohering plates. Two thick brass discs about eight centimetres wide, one slightly larger than the other, with handles.
Brass cohering rings with handles. Smaller base solid brass. Larger base has solid centre 75 mm with rounded additional rim. Two plates accurately finished so that when wrung together they would cohere due to natural interatomic boding between plates…
Magdeburg hemispheres. Two dark brass hollow hemispheres which fit together, with bright brass handles projecting from the top of each hemisphere. One has a short handle, the other has a long handle with a valve.
Demonstration of the great power of air pressure. When the comparatively small hemispheres are evacuated they are very difficult to pull apart, requiring a foce exceeding 400 N. Thick-walled brass hemispheres with central rim; one handle post with 2…
Chinese compass. A small rectangular wooden box with two rows of notches along its length on the top side. There is also a circular cavity with a pin in the centre on which the needle would have been. The cavity and notches have Chinese characters around them. There is a panel of wood with concentric rings and characters on it which slides out from the underside of the box; it has feet allowing it to stand in the notches.
Portable dial combines a compass whose needle is now missing, equinoctial sundial of traditional Chinese design (unseen in base), and a noon dial for telling the time of year. The equinoctial dial has shaped feet cut into to give it the correct…
Diving bell model. A glass bell with a brass fitting on top out of which a rubber tube projects. A length of string is tied to the fitting. Inside the bell is a rubber ring by the opening, suspended by wire from the top of the bell.
"Halley’s Diving Bell The diving bell made its appearance in the 16th century, under the name campana urinatoria, and accounts can be found of its use in the 17th century to recover sunken treasure. One adventure raised gold, chains and other…
Hadley's octant. An triangular ebony frame shaped like a section of a circle, with an ivory scale along the curved outer edge. A brass arm with a small scale and a screw at the end reaches from the point of the frame to the outer edge and can be rotated along it. There are three black glass discs in hinged brass frames on one side and the whole instrument stands flat on small brass legs.
Ebony frame with ivory scale having anchor engraved at its centre, calibrated in degrees, micrometer adjustment & Vernier to 1' arc. 1 green shade, 2 red shades. Double pin-hole site with moveable cover across a single pin-hole. Forerunner of the…
Dotchins. Small wooden boxes shaped like guitars with long necks, containing quills marked with scales from which metal dishes are suspended with string.
4 different sets of balances. Chinese balances in bamboo carrying cases known as Dotchins. They were used in the Chinese market place for weighing gold currency that consisted of irregular pieces stamped with their purity; violin-shaped wooden case…
