» Becquerel Toothed-wheel Fosforoscope (0044)
Immagini
DESCRIPTION
While it is easy to observe phosphorescence of objects that remain luminescent some seconds after exposition to light, for those objects for which the duration of the phenomenon is very brief, the direct observation is difficult (or impossible) without opportune devices. The Becquerel fluoroscope, which permits the observation of very brief phosphorescence, is formed by two disks mounted on the same axis, which present wedge-shaped openings alternately without superposition. That is, in correspondence of the opening in one disk the other is closed. There is a small volume between the two disks where the object to be examined can be placed through the external slot.Upon looking into the eyepiece, the observer sees absolute darkness even with the disks in rotation. If instead there is a phosphorescent object in the space between the two disks which is illuminated from the outside, the observer will see the florescent emission when the opening towards the outside is closed and the one nearer the observer is open, after a delay of the order of even a hundredth of a second.
In the exhibited model, the disks rotate 24 times for one rotation of the handle.
ISCRIZIONI
Sulla faccia è inciso: 'Phosphoroscope di E. Becquerel -¶
J.Duboscq à Paris'
Dati Catalografici
| Data di costruzione: | 1860-1870 |
|---|---|
| Data di carico: | 1873-09-01 |
| Nr. Inventario: | 700 (Generale dal 1874) |
| Costruttore: | J. Duboscq |
| Materiale: | ottone, legno, metallo |
| Dimensioni: | Ingombro totale: 15 cm x 18 cm x 11 cm Il corpo centrale è una cassetta cilindrica di diametro 11 cm e altezza 3 cm |
| Conservazione: | ottimo (Manca il supporto per inserire l'oggetto da studiare.) |