A practical pursuit of alchemy was the development of metallurgy practices.
As alchemists always tried to turn various metals into other things, metalworking techniques were developed even though their experiments were often unsuccessful.
the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.