1886.] 



MICROSCOPICAL JOURNAL. 



95 



Strong liquor am- 

 monia, 5 drachms. 

 For use add i part of a to 20 of 

 water, and i part of b to 20 of wa- 

 ter, and mix the solutions in equal 

 parts. 

 Formula ^. Carbutt's Developer. 



A. Water, 10 ounces. 

 Citric acid, 60 grains. 

 Ciystalized sulphite of 



soda, 3 ounces. 



Pyrogallic acid, i ounce. 



Water to make up to 16 ounces. 



B. Water, 10 ounces. 

 Crystalized sulphite of 



soda, 2 ounces. 



Carbonate of potash, 4 ounces. 

 Water to make up to 16 ounces. 

 Use J to 1^ drachm of A and b to 

 each ounce of water to make the de- 

 veloper. 



Formula 6. Newton's Developer. 



A. Washing soda, 500 grains. 

 Water, 10 ounces. 



B. Oxalic acid, 30 grains. 

 Pyrogallic acid, 30 grains. 

 Ammonium bromide, 10 grains. 

 Water, 10 ounces. 



Use equal parts of a and b. 



This formula was given before the 

 addition of sulphite of soda to the 

 developer became as universal as it is 

 now. The sulphite can be added to 

 the above without changing the other 

 proportions. 



Formula 7. Carbutt's Transpa- 

 rency Developer. 



A. Neutral oxalate potash S ounces. 

 Water, 32 " 

 Citric acid, 60 grains. 

 Potassium bromide, 180 " 



B. Fern^us sulphate, 2 ounces. 

 Water, 32 ''■ 

 Sulphuric acid, 8 drops. 



For use mix equal parts, pouring 

 B into A. 



This developer is intended to give 

 clear whites, and is probably as 

 good as any for transparencies. 



The Eastmann Dry Plate Company 

 have a pyrodeveloper consisting of 

 a single solution, which they sell. 

 It has only to be mixed with the 

 proper proportion of water, when it 



is ready for use. This is a very 

 convenient developer, especially if 

 one is travelling ; the only objection 

 we can see to it is that one can 

 scarcely have as perfect control over 

 the progress of development as when 

 the pyro and alkali are in separate 

 bottles, to be used as required. Still, 

 by changing the strength of the 

 solution one can exercise some con- 

 trol, and probably enough for most 

 cases. This developer also possesses 

 the advantage that it can be used 

 several times, so there is economy of 

 pyro. The developer probably does 

 not materially differ from others 

 except in the large quantity of sul- 

 phite it contains. 



Formula 8. Alum Solution. 

 Alum, I ounce. 



Water, 10 ounces. 



This solution is used for hardening 

 the gelatin film after development. 

 With ferrous oxalate development it 

 is onlv required in warm weather. 

 When developing with pyro, about 

 one drachm of oxalic acid should be 

 added to the above, the efiect of 

 which is to remove the yellow color, 

 which is often verv objectionable. 



Formula 9. Fixing Solution. 



Hyposulphite of Soda, 4 ounces. 



Water, 20 ounces. 



It is just as well to make a satu- 

 rated solution of the hyposulphite, 

 and to use it full strength or diluted 

 with a fourth its volume of water. 

 The strength of the solution is not of 

 much consequence, unless, as some 

 persons suppose, a strong solution 

 tends to cause frilling. 



\^To be continue d.\ 



Provisional Key to Classification of 

 AlgiP of Fresh Water.— Till. 



BY THE EDITOR. 

 {^Continued from p. JJ.] 

 The reader will observe that a mis- 

 take in numbering the families was 

 made on page 51 ; Conjugatfe should 

 be XI and Bacillariaceas should be 

 XII. We have now completed the 

 classification of the green algai, and 



