104 ON MARKING INK FOR MARKING LINEN, ETC. 
I believe, almost every druggist through the country has 
been in the habit of preparing and selling, when used ac- 
cording to the usual instructions, produces a result which 
is subject to no objection that does not equally apply to any 
other marking ink having silver as its basis. 
Within the last few years, however, the marking ink 
made as above, lias been to a great extent superseded by 
the introduction of a new kind of ink, which does not re- 
quire the use of a mordant or preparation. This ink ap- 
pears to be generally preferred to the other; — it is in one 
bottle, which occupies but little space, and its use is consi- 
dered to be attended with less trouble and inconvenience 
than that of the other. 
My attention has recently been directed to this subject, 
as I was desirous of introducing a good formula for mark- 
ing ink to be used as a mordant into the new edition, now 
publishing, of Gray's Supplement to the Pharmacopoeia, 
Several formulae have been published in the Journals, for 
the preparation of this ink, but none of these have given 
complete satisfaction. 
The following appear to be the principal requisites in 
this kind of ink : 
1st. That it shall flow freely from the pen, and form a 
well defined mark without running or blotting. 
2d. That it shall not require a very strong or long con- 
tinued heat to be applied, by holding the article that has 
been written on to the fire, or passing a hot iron over it, in 
order to develope the black mark required. 
3d. That the mark produced by it, when developed by 
the application of heat, or by exposure to light, shall be 
perfectly black. 
4th. That it shall not destroy the texture of even the 
finest cambric. 
After several experiments, I have succeeded in making a 
