What is the missing number?
MATH PUZZLE: Can you replace the question mark with a number?Correct answers: 95
The first user who solved this task is Djordje Timotijevic.
#brainteasers #math #riddles
Perkin patent for aniline dyeIn 1856, William Henry Perkin, an English chemist, applied for a British patent titled "Dyeing Fabrics" for his invention of aniline dye "producing a new coloring matter for dyeing with a lilac or purple color stuffs of silk, cotton, wool or other materials." It was sealed on 20 Feb 1857. This was the first synthetic dye, which he obtained at first unintentionally from coal tar (a by-product of coal gas production) while seeking a method to prepare the anti-malarial drug quinine from that source. Perkin was just 18 years old. With help from his father and brother, he began manufacturing the dye, which he called Tyrian purple. Within a few years, he was wealthy and in in 1873 sold the business to turn to chemistry full-time.« |