Flat metallic mirror with adjustable direction

36 x 24 x 21
Sculpted wood and iron

INDEX 1788 : V.III.369

Speculum planum metalicum corona lignea cinctum, cui in postica parte adnexa est pila ferrea, quae in alia concava includitur, quarum ope speculum moveri, et inclinari quaquaversum potest. Omnia insident tripodi ligneo: praesertim pro experimentis, in quibus lucem reflexam dirigere oportet.

Flat metallic mirror in a wooden frame with an iron ball fixed to the back and placed in another concave ball by means of which the mirror can be moved and inclined to all sides. Everything is fixed on a wooden tripod. Above all, for experiments that require light to take a reflected direction.

As described in the Index this is a metallic mirror, rectangular with a wooden frame and a sphere fixed to the back, half of which can be fitted perfectly into an iron cup fixed on the top of the tripod. Thus, the mirror can be adjusted to almost any desired position, making it possible to adjust it to receive a beam of light from any direction of incidence.

The wooden frame is very heavy which suggests that the hidden metallic part whose exterior surface makes up the mirror, is very thick.

From Colégio dos Nobres, catalogue n.° 363.

Carvalho, Rómulo de, História do Gabinete de Física da Universidade de Coimbra, Universidade de Coimbra, Biblioteca Geral, Coimbra, 1978, pp. 516-517.
's Gravesande, Willem Jacob, Physices Elementa, Leiden, 1742, Tomo II, § 3524, Tab. CXV, Fig. 2.

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