Magic Transistor

Gustave Le Gray, Un effet de soleil (An effect of the sun), Normandy, c. 1856.

William Henry, A Fishing Bark, c. 1745.

John C. Adams, Meteoric Shower, as seen off Cape Florida; The Midnight Sky (Edwin Dunkin), 1891.

Navigatore.

Gustave Doré, The Rime of the Ancient Mariner (Samuel Taylor Coleridge), Harper & Brothers, New York, 1876.

Zeevaart Kompas

W.B. Cooke, Eddystone Lighthouse [Line engravings on paper], Clarkson Frederick Stanfield's Coast Scenery, c. 1836.

Dutch fluyt, 1677.

The Carrack 'Henry Grace a Dieu' (Great Harry), c. 1546.

JF Nicholls, The SS Great Western (Bristol, Arrowsmith), 1882.

Designs and figures for astrolabes alongside a nautical sextant (with Blish prism attached), essentially, the device is a prism that diverts light rays through 180 degrees so that the horizon directly behind the observer can be viewed at the same time as the horizon in front and the amount of dip read out directly from the sextant’s scale. Inventors devised numerous instruments or attachments to do the same thing. Among the more complex dedicated instruments was one patented by Boris Gavrisheff in 1961 (US Patent number 2,981,143). A telescope views via two prisms light coming from one horizon behind the observer at the same time as the light from the horizon in front of the observer. One of the prisms is rotatable so that the deviation from 180 degrees, i.e. the dip, can be directly read off a micrometer drum. [Terra incognita]

Isambard Kingdom Brunel