APPENDIX. 



The various re-agents, mentioned in the " Laboratory work" 

 in the preceding pages, are prepared as follows : 



1. Acetic acid, Dilute. 



Mix i cub. centimetre of glacial acetic acid with 99 cub. 

 cent, of distilled water. 



2. Ammonic bichromate, Solution of. 



Dissolve 10 grammes of crystallized ammonic bichro- 

 mate in a litre of distilled water. 



3. Carmine, Solution of. 



Carmine 2 grammes. 



Strong solution of ammonia 4 cub. cent. 



Distilled water 48 cub. cent. 



Dissolve the carmine in the ammonia and water; leave 

 in an unstoppered bottle until nearly all smell of ammo- 

 nia has gone. Afterwards keep in a well-closed bottle. 

 Dilute a small quantity with fifteen or twenty times its 

 bulk of water, when required for use. 



4. Chromic acid, Solution of. 



Dissolve 10 grammes of crystals of chromic acid in one 

 litre of water. This gives a I per cent, solution, from 

 which weaker ones can readily be prepared when re- 

 quired. 



