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



All the inks of this species, though they resisted chlorine, were loosened by 

 weak acids, and by diluted alkaline solutions. These effects took place, even 

 after the writing had been strongly heated, and its surface washed over with al- 

 cohol, in the hope of fixing the albumen by coagulation. Another objection to 

 animal fluids as the vehicles of a liquid ink, is their speedy corruption and dis- 

 agreeable odour. 



Series IX. Carbon with Starch. 



Solutions of starch were next employed to suspend the carbon. 



1. I found great difl&culty in incorporating lamp-black with starch. The ink 

 thus formed is pale, unequal, and does not flow from the pen. 



2. Inks of this kind are not improved by the addition of iodine. 



Series X. Cai'bon with Gluten. 



The intimate mixture of carbonaceous matter with another vegetable sub- 

 stance afforded the results I had hoped. I need not occupy the time of the So- 

 ciety with a description of the numerous preliminary trials on this combination 

 of materials, but proceed to detail the process which appears to me capable of 

 affording a convenient, cheap, and durable writing ink. 



The qualities requisite for such an ink are : an easy process for its manufac- 

 ture from cheap materials ; a fluid which shaU flow as freely from the pen as 

 common ink, — which shall dry quickly, — which shall take such hold of the paper, 

 after it is dry, as not to nib off by a friction short of what injures the texture of 

 the paper, — which shall resist the chemical agents that efface common ink, un- 

 less they be so concentrated as to destroy the paper itself, — and which is not liable 

 to lose its colour by time. 



It is sufficiently obvious, that if an ink be only removable by means which 

 destroy the texture of the paper, it is sufficiently entitled to the appellation of 

 durable ; because no ink can be conceived capable of resisting an agent that de- 

 stroys the material to which it is applied ; nor have we any title to expect it to 

 resist such agent, any more than to be indestructible in the fire which consumes 

 the paper. 



The vehicle of my ink is vegetable gluten, dissolved in strong vinegar, 

 OR better in pyroligneous acid. 



This substance was suggested to me by the recollection of numerous experi- 

 ments, which I had made several years ago, on solutions of gluten as varnishes, 

 and the use of vinegar as a solvent, by a remarkable passage in Pliny, where he 

 treats of writing-inks : 



" Omne atramentum sole perficitur, librarium gummi, tectorium glutino ad- 

 misto. Quod autem aceto lique/actum, segre eluitur." 



