What flammable liquid derived from coal tar was essential for dissolving the raw rubber?

Answer

Coal-tar naphtha

Macintosh's quest that led to the coat began with his exploration of coal-tar naphtha, a substance derived from coal tar.

What flammable liquid derived from coal tar was essential for dissolving the raw rubber?

#Videos

The story of Charles Mackintosh - he invented rainwear! - YouTube

inventorrubberwaterproofMackintoshcoat