Kahn test magnifier. 
No. 3735. 
Achromatic 
In the use of the Kahn test, the observation of 
the degree of flocculation is difficult and_ this 
magnifier has been designed in conjunction with 
Dr. A. G. Signy to enable such observations to be 
made with ease. The test tube can be rotated and 
the flocculation examined on the inside of the tube 
either by daylight or by the self contained illumina- 
tion. The magnifying lens has a focussing adjust- 
ment. The instrument is supplied in a case with 
spare battery and lamp. The battery and lamp are 
standard articles, replacements of which can be 
obtained without trouble. 
No: 3735. 
Kahn test magnifier £1 10" 30 
pocket magnifiers. 
No. 3174. 
The optical properties of this series of magnifiers are of the highest order, giving a large, flat 
field of view free from distortion and colour. 
mounts and are supplied in leather cases. 
They are mounted in strongly made nickel plated 
Dia. of 
Cat. Dia. of | Magnifi- | Working | fjeld of | 
No. lenses. | cation. | distance.| yiew, £ 8s. d 
3171 Me 5 1.4” rn 20 
3172 625" | x12 ie oy hl 
3173 325" | x20 375" 534 male tae 0) 
3174 625" 10 & |) -8" & Th 
Double & 325" | x20 375" eine eral IRS} ae 
Magnifier | 
Workshop magnifier. 
This magnifier is made in two powers, x5 and X10, and is 
mounted into a substantial fitting with foot, and screw focussing 
motion as illustrated. The field of view given is flat and free 
from distortion and colour. 
| Dia. of field 
Cat. No. Magnification. of view. (hse 
3700 | x5 1-4" eles) 
3700A | x10 Ned 1 10 
