Temperature Coefficient of Resistance? #10697 Unsigned This device has a clamp for a short piece of wire with the ends connected to electrical terminals. Both the base and a cover have a hollow jacket with provisions for running water through them. Perhaps it was used to measure the temperature coefficient of resistance of various samples of wire.
Biprism? #10698 Duboscq á Paris and Ph. Pellin A fixed pair of small-angle prisms is mounted with a pair of variable slits behind them. The large circular flange fits the lens holders on some projectors.
Ball with Tubes
The wooden ball at the top of the support has three brass tubes projecting from it. The ball separates into two halves to reveal a small cavity at the center that connects to all three tubes.
A pill-box shaped container is hinged on one side and opens to reveal a rotatable pair of connected disks with holes not aligned with each other. A tube on the top allows a view to the inside, perhaps through the holes in the disk. This is similar to the "Phosphoroscope after Becquerel" listed in the Max Kohl List No. 100, Volumes II and II on pg 424, item #89157. What is the principle and how is it demonstrated?
Temperature Coefficient of Optical Activity?
My guess is that this is an apparatus for measuring the temperature coefficient of the optical activity of liquids. It consists of a metal box, insulated on the outside, with a horizontal sample tube inside which can be filled with liquid through a vertical tube. There are windows at the end of the sample tube through which polarized light could be sent. The two tubes on the top cover allow water of various temperatures to be circulated around the sample tube.
A cylinder with a stopcock and handle on top has a piston underneath connected to a stand. A similar device is described in the Cenco Catalogue F, 1923 called "Seven-in-one apparatus, (so-called Spirometer). It has three supporting legs and the following demonstrations using it are listed: hydrostatic paradox, hydroulic press, equality of fluid pressure in all directions, atmospheric pressure, pneumatic lift, elasticity of air, and Magdeburg Hemispheres." However, in the present apparatus the piton is fastened to a support stand making some of these demonstrations impossible.
Mystery Object II
A four-legged stand supports a vertical square steel bar with a long, fine screw t the bottom. Removing the brass pipe at the top reveals a broken glass tube.
This looks like a plumber's nightmare. A rectangular base has three wheels for mounting on an optical rail. A bracket for holding a missing miror is connected through a shaft to a second mirror, the combination being rotatable with an angle indicating scale. Another mounting arm has a rack and pinion adjustment but it is not known what is to be connected to it. The double mirror arrangement is, of course, characteristic of a heliostat, but there is no drive mechanism.