writing Ink. 
of the metal bad been dissolved, as would produce the required 
blackness. The fluid part of the mixture was then separated 
by straining, and thickened by gum. This composition, though 
differing in regard to the method of preparing it, resembles the 
prosubstantive black from acetate of iron and galls, commonly 
employed at this time by calico printers. 
At page 179, Caneparius describes a method of restoring Ancient, wri- 
the blackness of writings, which were, become illegible by age, by|^iJ^ t0re ^ 
and this was by an infusion of galls in white wine, which he 
afterwards subjected to an unnecessary distillation, and then 
applied the liquor to th q faded letters , by a sponge, or a little 
cotton, which, he says, rendered them as distinctly visible as 
when first written. Prussian blue was not then known, and, 
therefore, the application of its colouring matter for this pur- 
pose, (as recommended by Sir Charles Blagden) was impos- 
sible ) and that being the case, the means suggested by Cane- 
parius, (excepting the distillation) were the best \v hich could 
have been employed, and seem to indicate, that he must have 
justly imputed the loss of blackness in writing ink to ihe decay 
I of its vegetable, and not of its metallic part. 
Though two centuries have nearly elapsed since the publica- Modern re- 
tion of Caneparius’s work, no improvement of much impor- searches, 
tance seems to have been since made in the composition of 
writing ink. The late Dr. Lewis, indeed, bestowed particular Dr. Lewis, 
attention upon this subject j and his Philosophical Commerce 
of Arts contains some accurate, as well as judicious observa- 
tions relating to it ; especially in regard to the use of logwood, 
with which Caneparius does not seem to have been acquainted, 
at least as an ingredient in the composition of ink. 
The desired blackness of colour, as well as its durability, in Inquiries into 
. 1 • , , ..... the propor- 
this composition, depend entirely upon the proportions in which t j ons 0 f j n g re . 
the vegetable colouring matter, and the oxide of iron, are dients. 
united j though among the different recipes which have been 
published, the variations are so great as to manifest either cul- 
pable ignorance in the authors of them, or great diversities in 
the quality of the galls, from which the colouring matter is 
generally directed to be obtained : in some of these recipes, 
R 2 equal 
I 
