She only sells
what she couldn't
resist buying


Early 20th Century Scientific Physiological Instruments for Sound and Light
Date: early 20th Century
Dimensions: H 38cm W 17cm D 17cm
Shipping: $ 80

Beautiful early 20th century set of six educational instruments or 'apparatus' to teach the effects of sound and light. 
Three rotating mirrors, a lens, a prism and a chromed aluminium cone. All are on heavy cast iron tripods. The cone has a glass stand, the rest has metal stands.

The rotating mirrors where used to see the difference in two different frequencies with a manometric flame. The manometric flame device, was the first device that enabled an acoustic signal to be turned into a visible signal. The sound waves are made to modulate the supply of gas to a small flame, and the resulting variations in the height of the flame are viewed in a rotating mirror. You could measure sensory (auditory) perception and one could visualize sound vibrations with these cubes, the side surfaces of each of the cubes are mirrors. 
The prism quartz glass is mounted on a metal base, is adjustable in height and angles or degrees because of a adjustable hinge and ball. It was used to show the refraction of light through.
The double concave burning optic lens is also adjustable in height and can be rotated by loosen or fasten the little screws that hold it.
And a chromed aluminium cone, probably to do electricity tests with, as it is on a glass stand.

Two of the mirror stands are 30cm(11,8 inch) high and one of them has a 17:17cm(6,7 inch) wide tripod, the others have a 12:12cm(6,7 inch) tripod, one of them has a cracked mirror corner.
The third mirror stand is 24cm(9,6 inch) high and 12:12cm(4,7) wide, this mirror kubus looks different from the other two, this one has a wooden case, brass details and a silver coloured tripod. One of the mirrors side has a crack.

The lens on a stand is 38cm(15 inch) high in the highest position, the tripod base is 12:12cm(6,7 inch) wide.
The prism is 34cm(13,4 inch) high in the highest postion and 12:12cm(6,7 inch) wide.
The cone is 27cm(10,6 inch) high and its tripod is also 12:12cm(6,7 inch) wide.

This set of mirrors, the glass prism, the lens on a stand and the cone make a beautiful and decorative 'antique science' lot don't you think?


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