Having at hand every article requisite, proceed as follows:--Put the nitrate of potash into the mortar or dish; be sure it is dry and well powdered, and then add the acid; stir them well with the pestle and glass rod, so that the lumps will be all (or nearly so) out, and a pasty solution formed. This operation should not occupy more than two minutes' time. Then put in the cotton, about one-quarter of the whole bulk at a time: it should be well picked apart, so that it may come immediately in contact with the acids, and should be _kneaded_, with the pestle and glass rod, into the solution, and as soon as wetted, another quarter should be added and wetted as soon as possible; so continue until all is in: then _knead_ with the pestle and mortar for at least four minutes, or until every fibre of the cotton is _saturated_ with the liquid; then the mortar should be covered over with the pane of glass, and allowed to stand for fifteen or twenty minutes; then the entire contents of the mortar should be thrown into the pail two-thirds full of water, and stirred with the glass rod as rapidly as possible: if this rapid stirring is omitted, the cotton will be injured by the action of the acids in combining with the water. The water should be poured off, and another change put into the pail. After about three changes, the hands may be used in the farther washing. The hands should be perfectly clean, and free from _all chemicals_. The changes of water and washing should be continued until every trace of acid has disappeared, which can be seen by testing with blue litmus test-paper. After it is thought that the cotton has become free, the water may be squeezed out of a little lump about the size of a pea, and then placed between the fold of the test-paper, and if it reddens the paper, there is acid present, and the washing should be continued until there is no change in the paper. When this is done, the cotton can be put into the folds of a dry towel or cloth (which has been thoroughly rinsed, so that no soap be present), and wrung out as dry as possible, and then it may be picked apart and put aside, exposed to a moderate temperature (say 100° Fahr.) to dry, when it is ready for use. I employ the method (for convenience, nothing more) of displacing the water by the use of alcohol. [_Cutting's patent--see patents._] I wring out the water as before, then place the cotton in strong alcohol, stir and press it, and then pour it off; wring it out again, then put it in a change of alcohol, let it soak for about five minutes, then wring it out as dry as possible, pick it apart, and it will dry immediately, and place it in a close stoppered bottle; or, if wanted for use at once, put it into the dissolving solution immediately.