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A mid 19th century
travelling ivory thermometer by Stephen Bithray,
optician of North Gate, 29 Royal Exchange, London
(1827-1860 ) who was also noted for his microscopes.
This is not a medical thermometer. However it is
noteworthy that the scale is marked "Blood Heat" and
that the bulb of the thermometer has been position
through the plane of the ivory so that if the
thermometer is held by the bulb between thumb and
forefinger it can record a peripheral temperature. It
is a lovely example which has been finely engraved
with two scales, Fahrenheit and Réaumur (after René
Antoine Ferchault de Réaumur, who first proposed it in
1730). It is housed in a fitted round Moroccan leather
case with decorated silk and velvet lining. |
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