The alchemists' grasp of science is displayed quite concisely in the first few sentences of their front page:
The last building used by the Guild from that era still stands and is shown at right.
The photo's on the left.
Anyway, what do you get if you join up?
All new members receive a gilded Certificate of Membership (suitable for framing) which assigns you a license to practice alchemy
Rob has rightly noticed the absurdity that one can get a license for this, but has failed to point out the even greater absurdity that the certificate is gilded. Surely a more effective system of licensing would be to give members a plain paper certificate and only allow those with gilded certificates to practice.