THE CHEMISTRY OF INKS IN HANDWRITING. 



Bv C. AIXSWORTH MITCHELL. ]',.A. (Oxon). F.LC. 



mixture of a 

 of cojiperas 



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The general princiiiles underhing the chemical 

 methods of distinguishing between different kinds of 

 ink in handwriting have alread\- been described in 

 a former issue of " KxtJWLEDc.H." (1907. \'ol. iv, 

 p. 147), but before giving some account of further 

 applications of chemistr\- in this direction, I maw 

 perhaps, be allowed brietfy to recapitulate the main 

 outlines of the theor\ . and to add some details b\' 

 way of illustration. 



Ordinary writing ink is essentially 

 decoction of galls with a solution 

 (ferrous sulphate), which 

 slowh- interact to form an 

 iron tannate that gradually 

 becomes oxidised b\- ex- 

 posure to the air, and gives 

 the black pigment of hand- 

 writing. 



Characters written with 

 a pure iron gall ink are 

 nearlx' colourless when 

 first [Hit upon paper, and 

 a considerable time is 

 needed for the insoluble 

 black tannate to be formed 

 within the fibres. 



Prior to about the end 

 of the 18th century, inks 

 were exposed to the air or boiled, so that a partial 

 oxidation might take place within the fluid, and thus 

 give some depth of tint to the product before it was 

 used for writing. The chief objections to such 

 partial oxidation are that deposits are formed in tiie 

 bottle, and [irevent the ink flowing smoothh' from 

 the pen, and that the fluid has not the penetrating 

 [lower of an unoxidised ink. Such inks, however, 

 are still on the market, under the name of 

 "Japan inks," but they are but little used, their 

 place having been taken by unoxidised inks, in 

 which the black pigment is, as it were, in a latent 

 condition, and a second pigment, such as indigo, 

 logwood, or an aniline dve-stuff, is added to gi\'e a 

 colour to the writing pending the formation of the 

 iron tannate. 



The dye-stuff's em[)loyed in the commercial inks 

 of to-da\' var\- in colour from pale greenish-blue 

 to indigo and deep violet, and no two give 

 identical reactions — at all events when mixed with 

 iron tannate to form the pigment in writing. 

 It is mainly owing to the differences in these pro- 

 visional colouring matters that it is possible to 

 distinguish between handwriting written with different 

 kinds of ink. 



In the old type of iron gall ink, in which no such 

 second pigment was used, it would only have been 



^ ^ 



possible to distinguish between different makes of 

 ink in handwriting in exceptional cases, such as 

 when a large excess or a great deficienc\- of iron had 

 been used. Such irregularities in composition 

 might readih' occur, however: for in the days before 

 the ink manufacturer could have made a living, 

 writing was a polite accomplishment restricted to 

 those who could afford the time, and the ink was 

 made at home. Each housewife had her recipe for 

 making a good ink, and its preparation was as 

 much within her province as the making of cordials 



or the baking of bread. 

 .\ particularh' interest- 



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I'lGUKK 1. 



Kli/;iliethan dumcstic recipe for inakiiii,' iiil. 



ing exanijile of a domestic 

 recipe, which was handed 

 down as an heirloom, is 

 shown in the accompan\'- 

 ing figure, which Mr. G. 

 W'eddell has kindlvallowed 

 to be reproduced. 



This was taken from a 

 manuscript collection of 

 old famih' recijies dating 

 liack into the UithCenturw 

 whicli Mr. Weddell has 

 published in facsiiiiile 

 (/I rcci iia Fa i rfa xia na 

 Mani(scripta,]S9l)). Direc- 

 tions are given for making everything needed for 

 household use, from ajjple pasties to cures for the 

 king's evil, and among its odd assortment of items 

 are included several recipes for making ink, of 

 w hich the above example, which was probabh' written 

 towards the close of the 16th centur\-, is tvpical. 



The directions here given are to soak five ounces of 

 galls in one quart of rain water (or claret or red 

 vinegar) and to boil the decoction, after five da\'s" 

 standing, with four ounces of copperas and three 

 ounces of gum. 



Ink made under the rule-of-thumb methods of the 

 housewife must inevitably ha\e often varied w ideh- in 

 composition, and it is to such variations from the 

 right proportions of iron to galls that we must 

 attribute the want of permanencv of some relativeh- 

 modern writings, as compared with that upon 

 manuscripts centuries older. 



No more interesting illustration of this effect of 

 composition of ink upon the permanencv of writing 

 can be found than in the various names written on 

 the first page of Milton's family Bible, to be seen in 

 the British Museum. It will be noticed that all the 

 entries of the births of himself and the members of 

 his famil}- are in the handwriting of Milton, and that, 

 w ith one exception, all the inks are of a good dark 

 tone. The exception is seen in the entry of the 



387 



