Explosives, and Cellulose

The invention of dyeing lias been attributed to the Phoenicians, probably because it is chronicled that Solomon sent to Hiram of Tyre for a man cunning to work inter alia in purple and crimson and blue. The Tyrian purple was derived from the throats of a species of murex, a molluscous animal, a single drop from each. Other dyes from animal substances include sepia derived from the black secretion of the cuttlefish, and cochineal which consists of dried female cochineal insects, discovered by the Spaniards in 1518. 

The history of the subject covering the consideration of all the dyes known would fill volumes exceeding in bulk the Encyclopaedia Britannica. The number of dyes revealed by science and the substances which science can foretell with certainty would form dyes, and the myriad derivatives of known colouring matters, would run into many thousands, though 800 to 1000 should be more than sufficient for all practical purposes. 

Alizarin, the dyestuff contained in madder, is made from anthracene, another coal tar product, by the action of sodium bichromate and sulphuric acid to form antbraquinone this is traniSformed by the action of sulphuric acid into anthraquinone sulphonic acid, the sodium salt of which when fused with soda and a little potassium chlorate yields a compound of alizarin containing sodium, from which alizarin itself is made by the action of acid. 

Bieberich scarlet, one of the naphthol azo dyes, a very important group, is, like indigo, prepared from, naphthalene as starting material. 

These three examples serve to show how the laboratory and the factory have replaced tire cultivation field. There are also thousands of new dyes prepared from benzene, toluene, and carbolic acid, as well as many others from naphthalone, The name coal tar dyes, however, is rather misleading to the uninitiated, for it seems to imply that the dyes exist as such in the tar and only need extraction. What is meant, is that the raw materials are found in the tar and need to be transformed before anything of the nature of a dye can be produced- 

---

Sulphuric acid is used in making many other acids. As an example, nitric acid— tremendously important in manufacturing explosives and cellulose films—may be made in your home laboratory, but use a glass retort as nitric acid reacts on cork and rubber. Through a paper funnel, drop 25 grams of sodium nitrate into the retort. Carefully pour 20 cc. of concentrated sul-... 

---