Battered Old Eagle, Umm-umm (or Just a Fiscal?)

[Gordon Lee]

Greetings Fellow SB Boarders
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I just came across this old feller and just because I hate sitting something aside because I can't rightly identify it and know it's particulars, I thought I would ask.
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PRUSSIA -- Unknown
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I am guessing it is from the German States - Prussia because it says "Preussen" there on it's bottom. And, since I can find no illustration of this tattered old fellow in my copy of the Scott Catalogue, and because of the pen scripted cancellation, I assume it is a revenue stamp of some sort.
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This 20-pfennigs is perforated 13x14 and measures 22-1/2x29-1/2 mm.  I did not check to see if it is watermarked, fearing it would dissolve or fall all apart.
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I would be grateful if any Stamp Bear has any information about this old duck; such as, the purpose, issue date, and collectability.
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Respectfully,

Gordon Lee 

[khj]

It is indeed a Prussian revenue. In the Forbin catalog, it is Prussia #76(1896). It is the 2nd stamp in a set of 6 (10pf, 20pf, 50pf, 1m, 1.5m, 2m). All the revenues in this set are very common.

However, the Forbin has the perforation gauge listed as 13½.

[Gordon Lee]

Greetings Mr. khj
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You, sir, are the bee's knees. Thank you most kindly for the prompt Forbin information. The difference between the perforation can be credited to the humble condition of the stamp, or more likely, to the humble condition of my eyes.
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Again, thank you.
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Respectfully,

Gordon Lee