ON PHOTO-MICROGRAPHY. 



193 



For developing^ 



For hardening. 

 For fixing. 



' L f Pyrogallic acid . . 



I Distilled water .. 



f Ammonia solution 

 B ! Potassic Bromide 



I Distilled water . . 

 p f Potassic Bromide 



( Distilled water . . 

 -pv f Ammonia solution 



I Distilled water , 



Normal 

 developer. 



For intensifying. 



36 grains ^ 

 12 oz. 



I oz. 

 30 grains 



6oz. 

 15 grains 1 For over- 



1 oz. J exposure. 



1 drm. 1 For under- 



1 oz. J exposure. 

 Alum saturated solution in common water, 

 f Sodic hyposulphite, 4 oz. 

 I Common water, 1 pint. 



Mercuric chloride saturated solution in 



common water. 

 J Ammonia solution, 1 oz. 

 1 Common water, 8 oz. 



(Hydrochloric acid, 8 drops. 

 Forremovmgstams{ Common 



A beaker of about two and a half ounces capacity, 

 a drachm measure graduated to minims (60th of a 

 drachm-drops), a papier-mache tray, 4J by 3J, for 

 developing, a porcelain dish to hold the hyposulphite 

 of soda (" hypo "), another dish or tray of papier- 

 mache or porcelain to hold the alum, a broad camel- 

 hair brush, and an abundant supply of water should 

 also be in readiness. Operations may then be com- 

 menced by taking a plate from the box, and at once 

 replacing the lid, passing the brush gently over its 

 coated surface to remove particles of dust, and 

 placing it in the dark slide, previously dusted inside, 

 which is then to be shut up. Neither in this nor in 

 any other operation must the sensitive surface be 

 touched with the fingers. The slide is then carried 

 to the camera, placed in position, and the exposure 

 given. This, however, must not be done by simply 

 drawing the shutter, for in this act vibrations are 

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