APPENDIX. 



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

 in the preceding pages, are prepared as follows : 



1. Acetic acid, Dilute. 



Mix 1 cub. centimetre of glacial acetic acid with 99 cub. 

 cent, of distilled water. 



2. Ammonic bichromate, Solution of. 



Dissolve 10 grammes of crystallized ammonic bichromate 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 ammonia 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 1 per cent, solution, from which 

 weaker ones can readily be prepared when required. 



