Accession No

6802

Brief Description

two electrical demonstration motors, attributed to Charles William Collins, English or Scottish, 1840 (c)

Origin

England or Scotland

Maker

Collins, Charles William [attributed]

Class

electrical

Earliest Date

1840

Latest Date

1840

Inscription Date

Material

metal (brass)

Dimensions

6802.1 145mm(width) 230mm(height) 90mm(depth) 6802.2 100mm(width) 120mm(height) 850(depth)

Special Collection

Provenance

Purchased from Bonhams, London, England in 12/08/2023 Both objects were part of a private Collection, West Midlands, England, in 2008.

Inscription

Description Notes

Two electrical demonstration motors, attributed to Charles William Collins, English or Scottish, 1840 (c)

Two devices on brass stands with a metal circle that spins around a vertical axis, at the base of each circle are two wires that dip into a well that would have been filled with mercury. 6802.2 has a coiled wire cross bar inside the circle, that spins independently of the circle and has its own mercury well.

6802.1 The motor without the coiled wire cross bar
6802.2 With the coiled wire cross bar

Description taken from the Scientific Instrument Society's 25th Anniversary Exhibition;


"Each design is associated with the Scotsman William Ritchie (1790-1837), who was Rector of The Royal Tain Academy, Ross-shire and later studied in Paris under Thenard, Gay-Lussac and Biot. He then moved to London and obtained a Professorship at the Royal Institution.

Both instruments would have been connected to a battery and the ends of their wires touched the surface of a mercury meniscus. Aligning the mercury division with the earth’s magnetic meridian could produce continuous rotation.

Ritchie described a version of the second instrument [.1] in 1834. A very early form of electric motor dating from c.1835, it is based on the rotating electro-magnet seeking north and a commutator which would be filled with mercury to effect the reversal of the current every half turn. This would keep the electro-magnet rotating

In 1838 the instrument maker Charles William Collins (fl.1838-59) mounted two of Ritchie’s second instruments above each other, so that they rotated in opposite directions [.2]. Collins may have made these two instruments as, although Watkins and Hill (fl.1819-56) illustrate both in their catalogue, they do not ascribe either. However, the double instrument [.2] has a paper label [on the base] of the retailer, ‘F.T. HUDSON, Optician, Greenwich.’; this was Frederick T. Hudson (fl.1845"

References

Events