Chemical Instrumentation S. Z. LEWIN. N e w York University, Washington Square, New York 3, N. Y
T h i s series of articles presents a szcwe?l of the basic principles, chararleristics and limitations of those instruments which find important applications in chemical work. The emphasis i s on commercially available equipment, and approximate prices aTe quoted to shou: the order of magnitude of cost of the various t!,pes of design and construction.
9. Spectrophotometers (Cont'd)
corresponding gencrsl viow of the aotual instrument is shown in Figure 13. Light from thc sourcc illuminatrs a. condensing mirror, which brings the reflected heam to a focus a t the entrance dit, as shown
dry chloroform or carhon tetrachloride to remove dust and grea8~. The condensing mirror focuses an image of the lamp filament on the plane of the slit with a five-fold magnification. The magnified image is highly astigmatic and distorted, so that the slit opening is filled fairly uniformly with light. With the geometry employed, d l the light passing through the entrance slit originates from an area 0.6 mm wide by 3.1 mm high on the light source. This condensing system
'l'ho drwcloprnmt in the o d y 1940's of wid
