Perspective of the Laghu Samrat Yantra sundial

Perspective of the Laghu Samrat Yantra sundial, in two figures, attributed to Lieutenant colonel Archibald Campbell, chief-engineer for the East India Company.

The figure illustrates a paper by Robert Barker on the astronomical observatory Jantar Mantar, Jaipur completed in 1734 by order of Raja Jai Singh (1681-1743), founder of Jaipur.
The paper describes the observatory as disused, with lower parts of the edifice 'converted into a stable'. The edifice is incorrectly dated 'said to have been erected two hundred years' by Emperor Akbar (reign 1556-1605). Barker recognises the 'mathematical exactness' of the stone construction as modern and notes the extraordinary 'serenity and clearness of the atmosphere in the night time' outside of monsoon season.

Jantar Mantar is composed of 19 instruments, quadrants, sundials, only 5 are described and 1, the Laghu Samrat Yantra sundial, drawn in details.

Includes 3 plates, one watercolour view of Jantar Mantar, a watercolour prespective and cross-section of Laghu Samrat Yantra (sundial), attributed to then Lieuntenant Colonel Archibald Campbell, chief-engineer for the East India Company (future colonial governor of Madras, Georgia and Jamaica).

The paper was sent to the Royal Society and read at its meeting on 29 May 1777, it was then published in its journal, the Philosophical Transactions, as 'An account of the Bramin's observatory at Benares. By Sir Robert Barker, Knt. F.R.S.; in a letter to Sir John Pringle, Bart. P.R.S.'