190 



The inks used by the ancients were carbonaceous, and have ad- 

 mirably resisted the effects of time ; but the author found that the 

 specimens of writing on the Herculaneum and Egyptian pa/^^/ri were 

 effaced by washing with water; and on forming inks after the de- 

 scriptions of Vitruvius, Dioscorides, and Pliny, he found that they 

 did not flow freely from the pen, and did not resist water,_quali- 

 ties essential to a good writing-ink in modern practice. 



The carbonaceous inks with resinous vehicles, rendered fluid 

 by essential oils, though they resisted water and chemical agents, 

 had the disadvantages of not flowing freely from the pen, and of 

 spreading on the paper, so as to produce unseemly Imes. Solu- 

 tions of caoutchouc in coal-naphtha, and in a fragrant essential oil, 

 lately imported from South America, under the name of ocet^e rfe 

 sassafras (the natural produce of a supposed Laurus), were subject 

 to the same objections. 



The author tried various animal and vegetable fluids as vehicles 

 of the carbon, without obtaining the desired result, until he found, 



in A SOLUTION OF THE GLUTEN OF WHEAT IN PYROLIGNEGUS ACID, 



a fluid capable of readily uniting with carbon into an ink, possessmg 

 the qualities of a good, durable, writing ink. To prepare this ink, 

 he directs gluten of wheat to be separated from the starch as com- 

 pletely as possible, by the usual process, and when recent to be 

 dissolved in pyroligneous acid with the aid of heat. This forms a 

 saponaceous fluid, which is to be tempered with water until the 

 acid has the usual strength of vinegar. He grinds each ounce of 

 this fluid with from eight to ten grains of the best lamp-black, and 

 one and a half grain of indigo. The following are the qualities of 



this ink. 



1. It is formed of cheap materials. 



2. It is easily made, the colouring matter readily incorporating 



with the vehicle. 



3. Its colour is good. 



4. It flows freely from the pen. 



5. It dries quickly. 



6. When dry it is not removable by friction. 



7. It is not affected by soaking in water. 



8. Slips of paper written on by this ink have remained immersed 

 In solutions of the above-mentioned chemical agents, capable of im- 

 mediately effacing or impairing common ink, for seventy-two hours, 

 without change, unless the solutions be so concentrated as to injure 

 the texture of the paper. 



