PHOTOMICROGRAPHS AND LANTERN SLIDES 
159 
Green Tones.— 
Potassium bichromate (10 
Metric 
per 
Apothecaries’ 
cent solution in water).... 
... 60 
drops 
Potassium ferricyanide (10 
per 
cent solution in water). . . 
. . . 30 
c.c. 
( 1 OZ.) 
Water. 
... 120 
c.c. 
( 4 oz.) 
Cobalt chloride. 
... 3.9 
g- 
(60 gr.) 
Ferric sulphate. 
... 3.9 g. 
(60 gr.) 
Hydrochloric acid. 
... 15 
c.c. 
(h oz.) 
Water. 
... 120 
c.c. 
(4 oz.) 
Bleach in A, wash 10 minutes in water, tone in B, and then 
wash 20 minutes in water. 
Staining Lantern Slides. —Some of the stains used in staining 
microscope slides will give a pleasant tone to lantern slides. Light 
green gives a clear, moonlight effect. Magdala red gives a transparent, 
rosy tint. Sepia and other tones could doubtless be imitated by 
this easy method. 
Clearing Lantern Slides. —Sometimes a slide will seem perfectly 
clear, just as it comes from the fixing bath, especially from an acid 
fixing bath; usually, however, it will be better to transfer the slide 
from the fixing bath to a weak solution of acetic acid—just enough 
acid to give the solution the taste of weak vinegar—and then rock 
for a minute before washing. 
The following clearing fluid may be used in the same way: 
Metric Apothecaries’ 
Alum. 20 g. (1.3 gr.) 
Iron sulphate. 20 g. (1.3 gr.) 
Citric acid. 20 g. (1.3 gr.) 
Water. 500 c.c. (17 oz.) 
Coating Lantern Slides. —After the slide has become thoroughly 
dry, a coat of balsam or shellac will add much to its brilliancy. 
Dilute the Canada balsam with xylol until it becomes almost as 
thin as water; balance the slide on the thumb and first, second, and 
third fingers, holding it as level as possible; pour the balsam over 
it, letting the balsam flow evenly over the whole surface; then tilt 
the slide and pour the balsam back into the bottle. Put the slide in 
the rack to dry. 
Mounting. —Add a suitable mat and a clean lantern-slide cover. 
Remember that the effect of a first-class lantern slide may be impaired 
