Technology Electricity  &c Cometarium, Colleseum  Alexander Hogg  c.1788

Electrical  machine, Electrical Air Thermometer, Cometarium, Vaspasian's Amphitheatre (Colleseum)

Antique Copper engraving engraved by J. Page, printed on hand made hemp and flax laid paper.

Published "According to an Act of Parliament" by Alexander Hogg, at the Kings Arms No 16 Paternoster Row, London circa 1788

Condition= Excellent with no discolouring, foxing.

Here the Electrical Machine and Air Thermometer and Universal Discharger share the page with a"Cometarium", a mechanical model of a comet’s orbit, based on the action of elliptical cams. This apparatus was designed to demonstrate how the speed of a comet varies in its orbit according to Kepler’s law of equal areas. The comet Benjamin Martin chose for this instrument is Halley’s Comet. Roman Emperor Vespasian's Amphitheatre is the Collesum, built by  Emperor Titus Flavius Vespasianus, and it notes the structure "contained eighty  seven thousand spectators".

Plate mark = 23.5 x 38cm (9.4 x 15.2 inch)