Atmospheric pollution in Leicester : a scientific survey.
- Great Britain. Atmospheric Pollution Research Board.
- Date:
- 1945
Licence: Public Domain Mark
Credit: Atmospheric pollution in Leicester : a scientific survey. Source: Wellcome Collection.
36/178 page 24
![ible. Uniformity of silver deposit could be obtained to within 10%. Such a filter therefore satisfies condition (2) approximately. The transmitted light is about 250A longer in wavelength than was specified, and is outside the range of wavelengths which are strongly absorbed by atmospheric ozone. Conditions (4) and (5) were satisfied by using an optical wedge to vary the intensity of the light, and gaslight photographic printing paper as a light indicator. The wedge was designed to transmit 500 times as much ultra-violet radiation at the thin end as at the thick end. By adjusting the thickness of SETS SS I BOR ITT OT | \ Translucgne Silica bulbs qos ~ tT, YD NY yy \ \ Locking ring. Spring: Brass cap- = ae Insulating = = Earth-radiation ee! =] WG: = Sas Wood ring, ENS: zh i aed a 4d) Sil 1 Clear silica aS = )Silver Filter discs eS PROS OH ad Sealing wax. SSS = a os Z) Opticas wedge Paper stop: ae Wd (F) Graduated disc. | : \ G) Photographic paper h) Brass holder ilica gel. O Scale OF inches. Fic. 2:7 ULTRA-VIOLET DAYLIGHT INTEGRATOR.](https://iiif.wellcomecollection.org/image/b32179467_0036.jp2/full/800%2C/0/default.jpg)
