continues to disappear on well stirring, and a slight permanent precipitate remains. Then add the caustic soda. When the latter has dissolved, add a little more of the aqueous solution of perchloride of mercury, shake, allow to settle, and dilute the whole with distilled water to the volume of one pint. The solution should be kept in a stoppered bottle.
SOLUTION OF STANNOUS CHLORIDE.
Take of
| Granulated Tin | 1 ounce |
| Hydrochloric Acid | 3 fluid ounces |
| Distilled Water | a sufficiency |
Dilute the acid in a flask with one fluid ounce of the water, and, having added the tin, apply heat gently until gas ceases to be evolved. Add as much of the water as will make up the bulk to five fluid ounces, and transfer the solution, together with the undissolved tin, to a bottle with an accurately ground stopper.
SOLUTION OF SULPHATE OF INDIGO.
Take of
| Indigo, dry and in fine powder | 5 grains |
| Sulphuric Acid | 10 fluid ounces |
Mix the indigo with a fliud drachm of the sulphuric acid in a small test-tube, and heat on a water-bath for an hour. Pour the blue liquid into the remainder of the acid, agitate the mixture, and, when the undissolved indigo has subsided, decant the clear liquid into a stoppered bottle.
SOLUTION OF SULPHATE OF IRON.
Take of
| Granulated Sulphate of Iron | 10 grains |
| Boiling Distilled Water | 1 fluid ounce |
Dissolve and filter.
This solution should be recently prepared.
