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kept： and perhaps more gum was used in them；
or possible they were washed over with some kind
of varnish； though not such as gave gloss。
〃One of the specimens sent me by Mr。 Astle；
of the fifteenth century； and the letters were those
of an engrossing hand； angular； without any FINE
strokes； broad and very black。 On this none of
the above…mentioned re…agents produced any considerable
effect； most of them seemed to make the
letters blacker； probably by cleaning the surface；
and the acids； after having been rubbed strongly on
the letters； did not strike any deeper tinge with the
phlogisticated alkali。 Nothing had a sensible effect
toward obliterating these letters but what took off
part of the surface of the vellum； when small rolls；
as of a dirty matter； were to be perceived。 It is
therefore unquestionable； that no iron was used in
this ink； and from its resistance to the chemical
solvents； as well as a certain clotted appearance in
the letters when examined closely； and in some
places a slight degree of gloss； I have little doubt
but they were formed with a composition of a black；
sooty or carbonaceous powder and oil； probably
something like our present printer's ink； and am not
without suspicion that they were actually printed
（a subsequent examination of a larger portion of
this supposed MSS。 has shown that it is really a part
of a very ancient printed book）。
〃Whilst I was considering of the experiments
to be made； in order to ascertain the composition
of ancient inks； it occurred to me that perhaps one
of the best methods of restoring legibility to decayed
writing might be to join phlogisticated alkali
with the remaining calx of iron； because； as the
quantity of precipitate formed by these two substances
very much exceeds that of the iron alone；
the bulk of the colouring matter would thereby be
greatly augmented。 M。 Bergman was of opinion
that the blue precipitate contains only between a
fifth and a sixth part of its weight of iron； and
though subsequent experiments tend to show that；
in some cases at least； the proportion of iron is
much greater； yet upon the whole it is certainly
true； that if the iron left by the stroke of a pen
were joined to the colouring matter of phlogisticated
alkali； the quantity of Prussian blue thence
resulting would be much greater than the quantity
of black matter originally contained in the ink
deposited by the pen； though perhaps the body of
colour might not be equally augmented。 To bring
the idea to the test； I made a few experiments as
follows：
〃The phlogisticated alkali was rubbed upon the
bare writing in different quantities； but in general
with little effect。 In a few instances； however； it
gave a bluish tinge to the letters； and increased
their intensity； probably where something of an
acid nature had contributed to the diminution of
their colour。
〃Reflecting that when phlogisticated alkali forms
its blue precipitate with iron the metal is first usually
dissolved in an acid； I was next induced to try the
effect of adding a dilute mineral acid to writing besides
the alkali。 This answered fully to my expectations；
the letters changing very speedily to a deep
blue colour； of great beauty and intensity。
〃It seems of little consequence as to the strength
of colour obtained； whether the writing be first wetted
with the acid； and then the phlogisticated alkali be
touched upon it； or whether the process be inverted；
beginning with the alkali； but on another account
I think the latter way preferable。 For the principal
inconvenience which occurs in the proposed
method of restoring MSS。 is； that the colour frequently
spreads； and so much blots the parchment
as to detract greatly from the legibility； now this
appears to happen in a less degree when the alkali
is put on first； and the dilute acid is added upon it。
〃The method I have hitherto found to answer
best has been to spread the alkali thin with a
feather or a bit of stick cut to a blunt point； though
the alkali has occasioned no sensible change of
colour； yet the moment that the acid comes upon it；
every trace of a letter turns at once to a fine blue；
which soon acquires its full intensity； and is beyond
comparison stronger than the colour of the original
trace had been。 If now the corner of a bit of blotting
paper be carefully and dexterously applied
near the letters； in order to suck up the superfluous
liquor； the staining of the parchment may be in a
great measure avoided： for it is this superfluous
liquor which absorbing part of the colouring matter
from the letters becomes a dye to whatever it touches。
Care must be taken not to bring the blotting paper
in contact with the letters； because the colouring
matter is soft whilst wet； and may easily be rubbed
off。 The acid I have chiefly employed has been
the marine； but both the vitriolic and nitrous succeed
very well。 They should undoubtedly be so
far diluted as not to be in danger of corroding the
parchment； after which the degree of strength does
not seem to be a matter of much nicety。
〃The method now commonly practiced to restore
old writings； is by wetting them with an infusion
of galls in white wine。〃
（See a complicated process for the preparation of
such a liquor in Caneparius De Atramentis； A。 D。
1660； p。 277）
〃This certainly has a great effect； but is subject；
in some degree； to the same inconvenience as the
phlogisticated alkali； of staining the substance on
which the writing was made。 Perhaps if； instead
of galls themselves； the peculiar acid of or other
matter which strikes the black with iron were separated
from the simple astringent matter； for which
purpose two different processes are given by Piesenbring
and by Scheele； this inconvenience might
be avoided。 It is not improbable； likewise； that a
phlogisticated alkali might be prepared better suited
to this object than the common； as by rendering it
as free as possible from iron； diluting it to a certain
degree； or substituting the volatile alkali for the
fixed。 Experiment would most likely point out
many other means of improving the process described
above； but in its present state I hope it
may be of some use； as it not only brings out a
prodigious body of colour upon letters which were
before so pale as to be almost invisible； but has
the further advantages over the infusions of galls；
that it produces its effect immediately； and can be
confined to these letters only for which such assistance
is wanted。〃
The Society of Arts in 1830； received a communication
from Dr。 Bostock； in the course of which he
stated that the 〃tannin； mucilage and extractive
matter are without doubt the principal causes of the
difficulty which is encountered in the formation of a
perfect and durable ink and for a good ink the essential
ingredients are gallic acid and a sesqui salt of
iron。〃 Owing to his working with galls he was unable
to make decisive experiments； but he concludes；
and that rightly； that in proportion as ink consists
merely of gallate of iron； it is less liable to decomposition
and any kind of metamorphosis。
In 1831 the Academy of Sciences in France took
up the matter and designated a committee composed
of chemists with instructions to study the subject of a
permanent ink。 After long research it reported that
it was unable to recommend any better ink than the
tanno…gallate of iron one then in use； but 〃it should
be properly compounded。〃
Peddington investigated； 1841…48； the ancient MSS。
collected by the Asiatic Society of Bengal； Calcutta；
and published the results in 〃Examination of Some
Decayed Oriental Works in the Library of the Asiatic
Society；〃 which are of much interest as relating to
〃mineral〃 inks； the 〃gall〃 inks being unknown in
Asia after the twelfth century。
Up to thirty…five years ago； the manufacture of
〃gall〃 inks necessitated a complicated series of processes
and long periods of time to enable the ink to
settle properly； etc。 It was Professor Penny of the
Anderson University who suggested the way to avoid
one of the processes pertaining to ink…making by
utilizing the known fact； that tannin is more soluble
in cold than in warm or hot water。 It was adopted
all over the world and revolutionized the manufacture
of ink； by doing away with boiling processes and hot
macerations of ingredients。 With hardly in exception
the best tanno…gallate of iron （〃gall〃） inks are
now 〃cold〃 made。
CHAPTER XIII。
STUDY OF INK。
INVESTIGATIONS BY STARK OF INK QUALITIES COVERING
A PERIOD OF TWENTY…THREE YEARSABSTRACT FROM
HIS REPORT OF 1855DR。 CHILTON EXPERIMENTS IN
NEW YORK CITY 1856ACTION OF THE PRUSSIAN
GOVERNMENT IN 1859 AND EMPLOYMENT OF AN OFFICIAL
INKWATTENBACH'S GERMAN TREATISE ON THE
ARCHIVES OF THE MIDDLE AGESWILLIAM INGLIS
CLARK ATTEMPTS TO PL