INDELIBLE WRITING INKS, 145 
of writing ink seems to have been overlooked. Any 
person having to search old documents for information 
must have observed the difficulty there is in deciphering 
some of the very old ones, the ink having faded to such a 
degree as to make them almost illegible; even now, deeds 
may be seen which were prepared in this colony in former 
days on which the Governor’s signature has almost disap- 
peared. If such be the case in so short a period of time, 
what will be the result in the course of centuries? Simply, 
many valuable documents will then be sheets of almost 
blank paper or parchment, probably having yellow stains, 
but perfectly illegible. It must be admitted that the 
Chinese are in advance of us in this respect. They have 
long had the credit of being excellent colour manufacturers, 
and a carbon ink has been used by them from time imme- 
morial. A similar ink must have been used by the ancient 
monks in Europe for making copies of the Scriptures, 
which now retain their blackness. If they had been written 
with ink like that now in use, which is simply a stain con- 
taining no carbon, they would in all probability have faded 
out centuries ago. 
Let us now consider the composition of our modern and 
ancient inks 
Mr. Underwood, an ink manufacturer, who read a paper 
upon this subject before the Society of Arts in 1857, thinks 
that some old inks were merely carbon pigments like the 
Indian Ink of the present day, while other kinds were 
veritable dyes of iron and acids (true chemical compounds), 
with the addition of a great deal of carbon. 
The usual constituents of black writing ink are galls, 
sulphate of iron, and gum-arabic. In place of the galls, 
wattle and gum barks would answer the purpose. The 
gum is used for the purpose of holding the colouring matter 
in suspension, and to prevent the mixture from becoming 
too fluid. 
Stephens’s blue-black ink, which in a short time after 
writing becomes a very deep black, is the most used in the 
present day. It consists of gallo-tanate of iron dissolved 
in sulphate of indigo, the indigo giving it the blue appear- 
ance. This ink appears blue when first put on the paper, 
but after a time takes up oxygen from the atmosphere, and 
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