Photomicrographs and Lantern Slides 147 



Cleaning 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. 

 Bind the two together with a lantern-slide binding strip. Paste on 

 the label, or, if you prefer, put the label on the mat before binding, 

 so as to have it protected by the cover. Lay the slide down so that 

 the positions are just as they were in the original, and then paste the 

 "thumb mark" in the lower left-hand corner. 



