Popular Science Monthly 



87-7 



Crude carbolic acid plant. Phenols, cresols, 

 xylols are washed with caustic soda. The 

 phenol is freed from soda with acids 



Coal tar dyes lend themselves so easily 

 to coloring all substances capable of being 

 colored that they are only too frequently 

 abused. The illustration on page 875 

 shows a doll made by Prof. D. R. Hodgdon, 

 who wished to call attention to the deleteri- 

 ous use of aniline dyes in candy. Miss 

 F. P. Sweets (Fraudulent Poisonous) con- 

 tains poisons extracted from cheap confec- 

 tions, such as lollypops and all-day-suckers. 

 The glue which holds her hair on, the 

 brilliant pink dress and green stockings, 

 the copper on her knife blade, and the 

 lampblack on her 

 shiny shoes are all 

 right in their place, 

 but surely that place 

 is not a child's 

 stomach. 



Although an Eng- 

 lishman discovered 

 the first coal tar 

 dye, the German 

 and not the English 

 developed his dis- 

 covery commercial- 

 ly. They succeeded 

 so well that they 

 destroyed the nat- 

 ural dye industry. 

 Then Indiasuddenly 

 found that her in- 

 digo plantations 

 were ruined. So 

 cochineal, and min- 

 eral dyes, like Prus- 

 sian blue and chrome 

 yellow, have been 

 rapidly giving place 

 to the modern syn- 



Huge benzol stills. The apparatus at the 

 right is an agitator in which benzol is washed 

 with sulphuric acid before entering the stills 



From the refining stills, 71 and 72, the 

 phenol passes into the cooling tanks above, 

 and then into the large receivers below 



thetic dyes, now prepared from coal tar. 

 An average tar yields seventy per cent 

 of pitch and only six per cent of materials 

 useful in making dyes. In the United 

 States, ninety per cent of the tar goes 

 to make better roads and better roofs, 

 and also for the manufacture of creosote oil, 

 naphthalene and other profitable products. 

 After leaving coal tar, the next station is 

 benzol. Benzol is an extremely inflamma- 

 ble, colorless liquid obtained as previously 

 stated, by the destructive distillation of 

 coal tar. It is the basic product for the 

 manufacture of ani- 

 line colors and also 

 cheap varnishes. It 

 is used for many 

 other purposes, chief 

 among them being 

 the manufacture of 

 explosives. 



Before the Euro- 

 pean war, the nor- 

 mal production of 

 benzol in the United 

 States was approxi- 

 mately 3,000,000 

 gallons annually. 

 Since the war, many 

 steel companies, and 

 other similar indus- 

 tries, which could 

 recover benzol from 

 their other opera- 

 tions, have been do- 

 ing so. Result — in 

 1916, upwards of 

 15,000,000 gallons 

 were produced. If 

 every man, woman 



