This should not be required if the stock solution is properly prepared.
This forms the stock solution and will keep for a long time if well corked.
What is called the stock solution is made as follows: 15 grs.
The other stock solution is a saturated solution of bicarbonate of soda.
If the time of appearance is less than 40 seconds, add the smaller quantity of stock solution; if more, add the greater.
This stock solution is mixed with four or five parts of water, when the mixture is ready for use.
Or to a pint of the stock solution, as it is called, you may add three pints of water.
Put this in your stock solution bottle, and keep it in a dark place for twenty-four hours.
If the stock solution is greenish white and turbid, undissolved indigo white is present.
Add then not more than a teaspoonful at a time caustic soda solution until the stock solution answers the glass test.
