BY H. W. FOX, ESQ. 147 
require and get much washing, thereby giving the ink a 
good crucial test, which it has stood remarkably well, not 
becoming obliterated or changed in colour, but turning 
greyer on account of some of the particles of carbon being 
washed away. 
The scientific reason of this ink standing so well is that 
it being composed of carbon and gelatine, the gelatine 
entering into the texture of the fabric, becomes insoluble in 
water by admixture with the tannin still contained in the 
fabric, quite sufficient remaining to produce that effect ; the 
gelatine thus becoming insoluble retains particles of the 
unalterable carbon, which, consequently, remain in the 
texture of the cotton or linen fabric till it is worn out by 
usage ; no amount of washing being sufficient to eradicate 
them. Such is also the case when used on paper which is 
made of such fabrics. 
It is well known by experienced draftsmen, that if a 
drawing made in Indian ink is often washed with a sponge 
and water, and a portion of the upper surface of the ink re- 
moved, still leaving sufficient in the pores of the paper 
for the drawing to be still dark, this removal of the free ink 
allows washes of colours to be made over the drawing with- 
out smearing. Again, if it is desirable to varnish a strong, 
black Indian ink drawing, the ink having been prepared 
for the purpose, a gelatine size can be brushed over the 
surface without making the ink run, such size being neces- 
sary before varnishing, as the oil in the varnish would 
penetrate the pores of the paper, causing it to become 
semi-transparent, which is very undesirable, as a dark 
yellowish tint is thereby occasioned. 
If the drawing has been made with ordinary Indian ink, 
the gelatine size would dissolve the upper stratum, the 
tannin in the paper being insufficient to harden the whole 
of the ink, but by mixing the ink with certain chemical 
solutions this is obviated. 
Now, why not use such an ink for ordinary writing? It 
runs easily enough from the pen, and the only trouble 
would be the mixing before using. It might necessitate 
the keeping of a small bottle of the chemical solution to 
mix with the ink (a number of chemicals may be used 
for this purpose), but no doubt a method would soon 
