sympathetic ink

American  

[sim-puh-thet-ik ingk] / ˌsɪm pəˈθɛt ɪk ˈɪŋk /

noun

1. invisible ink.

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sympathetic ink British  

noun

1. another term for invisible ink

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Etymology

Origin of sympathetic ink

First recorded in 1715–25

Example Sentences

Cobalt, dissolved in aqua regia, makes an excellent sympathetic ink, appearing green when held to the fire, and disappearing when cold, unless it has been heated too much, when it burns the paper.

From Heads of Lectures on a Course of Experimental Philosophy: Particularly Including Chemistry by Priestley, Joseph

It appears that there is much correspondence with sympathetic ink at Zossen.

From The Better Germany in War Time Being some Facts towards Fellowship by Picton, Harold W. (Harold Williams)

So far as Massachusetts was concerned, the Declaration of Independence was interlined upon it in sympathetic ink.

From The Atlantic Monthly, Volume 03, No. 18, April, 1859 by Various

They seemed to bring out like acid on sympathetic ink the miracle of a Mr. Hyde where his comrades had known only a Doctor Jekyll.

From The Law of Hemlock Mountain by Lundsford, Hugh

But the American captain was in no way daunted, and the next day wrote in sympathetic ink to Preble, telling him to keep up his fire, for the Tripolitans were greatly harassed by it.

From The Naval History of the United States Volume 1 by Abbot, Willis J. (Willis John)