Perspective Drawing Instruments, the Tripod and Carnac
An axonometric projection created using the second type of drawing instrument. Courtesy of the Institution of Engineering and Technology (IET) Archives
Sir Francis Ronalds' first type of drawing instrument for creating perspective pictures from life. IET
Sir Francis' second type of drawing instrument for creating perspective pictures from the plan and elevations. IET
Sir Francis Ronalds' sketch made using his first type of perspective drawing instrument. The model is a statue of Hermes, probably in the Royal Botanic Gardens at Kew. IET
Sir Francis Ronalds patented two instruments in 1825 to aid perspective drawing.
The perspectograph enabled a scene, object or person to be traced from life onto paper - simply, quickly and accurately. It proved to be a great source of entertainment for family and friends in the era before photography. Its high precision was also of scientific value: Sir Francis and his friend Dr Alexander Blair were able to document the important Neolithic monuments at Carnac, France, with "almost photographic accuracy" at an early period before further deterioration occurred.
The second machine was even more ingenious, producing a perspective view of an object directly from drawings of the plan and elevations. It served the growing need as the industrial revolution progressed for engineers and architects to communicate through technical drawing. Sir Francis used the instrument to illustrate and explain his inventions.
He also created a tripod stand to support his drawing board in the field. It had three pairs of legs that were hinged to a triangular metal head.
Sir Francis set up a production facility to make his devices and hundreds were sold. Examples are retained in several British museums and they still come up for sale at auction houses. The tripod stand was soon imitated by others and remains the classic portable support today for telescopes, surveying equipment and cameras.
How the two tracing instruments worked is explained in Sir Francis Ronalds: Father of the Electric Telegraph (2016)
- published by Imperial College Press
Alexander Blair & Sir Francis Ronalds' Sketches at Carnac (Brittany) in 1834
Surveying the Carnac Stones in 1834 - published by Histories of Archaeology Research Network - a blog
Sir Francis Ronalds' engraving of Croydon Palace (1827) drawn using his perspectograph