PROFESSOR TRAILL ON THE COMPOSITION OF A NEW WRITING-INK. 421) 



I have thus, Gentlemen, without reserve, submitted to you the results of an 

 investigation, which, unless I deceive myself, promises to be of public utility. 



Should it be found to present an obstacle to the commission of crime, — should 

 it, even in a single instance, prevent the perpetration of an offence so injurious in 

 its consequences to society, as the falsification of a public or a private document, 

 the author will rejoice in the publication of his discovery, and consider that his 

 labour has not been in vain. 



P. S. — Since this communication was made to the Royal Society, I obtained 

 in London a " prepared paper," from which it was pretended that common ink 

 could not be removed by chemical agents ; but letters written on it with common 

 ink, were instantly effaced by chlorine and by oxalic acid. 



Good wheat flour will yield fi:'om 14 to 24 per cent, of moist gluten ; but the 

 quantity appears to be exceedingly variable, according to the quality of the flour, 

 and perhaps also to the season. In lately preparing a large quantity of my ink, 

 for the use of The National Bank of Scotland, Messrs Duncan and Flockhart 

 found one sample of wheat to afford 14.73 per cent, of gluten ; another yielded 

 no more than 8.40 per cent. Barley and rye meal seldom give more than 4 or 5 

 per cent, of that substance. 



It has been stated that my ink, though it resist the stronger chemical agents, 

 is liable to be washed off paper by simple water. I had discovered that, when 

 used on highly-sized or very highly-glazed paper, it does not adhere very firmly. 

 The reason is obvious : the size or glaze prevents the ink from really coming into 

 contact with the paper. They form a varnish that defends its surface from 

 any ink ; which, to be permanent, must sink into the substance of the paper. 

 On other paper this new ink is not removable by water. It answers best on a 

 paper not too highly glazed or sized ; and, with a light pen, may be even used on 

 unsized paper. 



Several forgeries have of late been successfully perpetrated on some of the 

 Scottish banks by the following stratagem. Bank orders for small sums were 

 obtained on some of their country branches. The blank space in the engraved 



bill was filled up, as usual, in writing with common ink, thus — " Fou7' 



Pounds.'" The dash after the word Four was deleted bv chemical means, and 

 the word " Hundred'" inserted. The fraud has been but too successful. In con- 

 sequence of its detection, one most respectable bank, after instituting numerous 

 experiments on my ink, and ascertaining its durahility, have already had 100 

 gallons of it prepared by Messrs Duncan and Flockhart of this city, and sent to 

 their numerous country branches ; and have directed it to be employed to fill up 

 all bills, orders, &c. drawn on the bank. 



