This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1904 edition. Excerpt: ...that we have found to yield suitable solutions for writing inks are about 1 gramme in 50 to 80 c.c. of water, according to the tiuctorial power of the particular dye-stuff. The inks thus made are very fluid, and in this respect particularly suitable for stylographic and other descriptions of fountain pens. If a suitable dye-stuff be used there will be no precipitation, and therefore no suspension of particles in the liquid. There is, therefore, no need to add gum to inks of this description; indeed, such an addition would tend to counteract one of their most valuable properties--their fluidity. It is necessary to mention this point, because we have found many published formulae for aniline inks in which sugar or gum is erroneously included as a necessary constituent. Patent Coloured Inks.--Reade, in his patent (No. 11,474, 1846), claimed the use of inks containing " soluble Prussian blue," prepared in a specified manner, and of a red ink prepared from cochineal. A lake of cochineal extract and alum dissolved in ammonia solution was also claimed by Wood in 1885 (Eng. Pat., No. 1676). The use of aniline dyes was first claimed in this country by Croc'va. 1861 (Eng. Pat., No. 2972), and in the following year by Annaud (Eng. Pat., No. 675, 1862). Pigments from aniline waste were proposed as the source of writing inks by de la Rue (Eng. Pat., No. 2235, 1862), whilst aniline dye-stuffs were again patented by Jefferies in 1879 (Eng. Pat., No. 3391). For other patents in which coloured pigments are claimed see Copying Inks, Sympathetic hiks and Ink Powders. CHAPTER VII. EXAMINATION OF WRITING INKS. Contents.--Fluidity of ink--Penetration through paper--Stickiness of writing--Composition of commercial inks--Schluttig and Neumann's stripe...