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Here is a very quick way of producing something like the slow result of sunlight with silver nitrate. The fumes of ammonia have formed the precipitate of black mercurous nitrate, a very distinct black writing which is almost indelible. That is what is technically called invisible rather than sympathetic ink." We leaned over to read what he had written.
"But he forgot that after he had brought out the red writing by the use of the sulpho-cyanide, and though he could count on Vera Lytton's placing the note in the jar of ammonia and hence obliterating the writing, while at the same time the invisible writing in the mercurous nitrate involving Dr.
It is essential that the solution should be cold and that the stannous chloride should not be present in great excess, otherwise a secondary reaction takes place, resulting in the reduction of the mercurous chloride to metallic mercury: SnCl + 2HgCl > SnCl + 2Hg. Heat at a temperature just below boiling until the undissolved residue is white or until solvent action has ceased.
I have here a cylindrical glass jar in which I place some sal-ammoniac and quicklime. I will wet it and heat it a little. That produces the pungent gas of ammonia. "On one side of this third piece of paper I myself write with this mercurous nitrate solution. You see, I leave no mark on the paper as I write. I fold it up and drop it into the jar-and in a few seconds withdraw it.
The latter object is accomplished by oxidation to stannic chloride by means of mercuric chloride added in excess, as the mercuric salts have no effect upon ferrous iron or the bichromate. The reactions involved are: 2FeCl + SnCl > 2FeCl + SnCl SnCl + 2HgCl > SnCl + 2HgCl The mercurous chloride is precipitated.
"But he forgot that after he had brought out the red writing by the use of the sulpho-cyanide, and though he could count on Vera Lytton's placing the note in the jar of ammonia and hence obliterating the writing, while at the same time the invisible writing in the mercurous nitrate involving Dr.
I have here a cylindrical glass jar in which I place some sal-ammoniac and quicklime. I will wet it and heat it a little. That produces the pungent gas of ammonia. "On one side of this third piece of paper I myself write with this mercurous nitrate solution. You see, I leave no mark on the paper as I write. I fold it up and drop it into the jar and in a few seconds withdraw it.
The Latimer Clark "standard" cell is used by electricians in testing, as a constant electromotive force. It consists of a pure zinc plate separated from a pool of mercury by a paste of mercurous proto-sulphate and saturated solution of sulphate of zinc.
Here is a very quick way of producing something like the slow result of sunlight with silver nitrate. The fumes of ammonia have formed the precipitate of black mercurous nitrate, a very distinct black writing which is almost indelible. That is what is technically called invisible rather than sympathetic ink." We leaned over to read what he had written.
I have here a cylindrical glass jar in which I place some sal-ammoniac and quicklime. I will wet it and heat it a little. That produces the pungent gas of ammonia. "On one side of this third piece of paper I myself write with this mercurous nitrate solution. You see, I leave no mark on the paper as I write. I fold it up and drop it into the jar and in a few seconds withdraw it.