Alchemy may be the most fascinating phenomenon in the history of science: centuries of laborious effort in pursuit of goals which to the modern mind seem self-evidently crazy. I can think of no better illustration than Psuedo-Geber's description of the way to "silver" copper and iron. First, follow these instructions:
[T]ake as much as you wish of the stone mixed with its mixture and grind it with some water, mixed with copperas and sal ammoniac until it becomes black. Then put it very near a very slight heat until it smells like semen [sic]. When it has that smell take it away and wash it slowly with some clear water, and then roast it gently until you notice a visible vapour. In this way its water will be driven off, and the stone itself will become light, without losing its essence. Take it off and dip it again into water, powdering it under water, and roast it as before. Its blackness begins to diminish. Take off the stone when it is dry and its water absorbed. Grind it well in some clear water and roast it again. It begins to be green, and then this blackness will disappear. When you see the stone beginning to turn green, be sure you are in the right path. Move it then when it becomes quite green and has the appearance of verdigris. This will show that the process is right, and the stone has lost its sal ammoniac which would have corrupted it. After powdering it in some water, put it into a vessel well luted with plaster, place it on a gentle fire, and distil off all its water. Be patient and do not be in a hurry to increase the fire which will corrupt it; for you will repent, and your repentance will never be of avail. When you distil off all its water, take it off, and powder it in the same distilled water. Then return it to the vessel, and renew the distillation.
Now, you'd be forgiven for thinking that this was the end of the process, but actually it's just the beginning:
I recommend you to distil it 700 times [emphasis added] like the rods of myrtle, and Indian cane. I have not explained this hint in any one of my books, but in this only. I have told you the opinion of philosophers without diminishing or increase, and have not concealed anything from you. When the stone becomes green we call it myrtle, and when it returns to yellow, we give it the name of Indian cane. You must know that it becomes gradually black from the first to the last. It remains quite black from five to ten roastings; then it slowly becomes green, and has the colour completely in 50 or 70 roastings. This is the end. If the stone acquires these qualities, there will be no doubt of its goodness. Its yellow colour begins bye-and-bye to disappear and the stone will completely lose its clearness in 70 roastings. Then the stone will have the same degree as the sun, and similar coloured rays. It will burn, and become ashes. They are the same ashes mentioned in the books of philosophers. If you continue the same process, the ashes will become quite white. This is the fourth sign, which is the sign of perfection. Therefore you must continue to proceed as before without diminishing or increase. Then it is necessary to augment the fire just a little, and do not fear the corruption. If you continue to distil it you must return the distilled water on it, and in every distillation the water diminishes; therefore it is necessary, every ten distillations, to add some clear water to the distilled water with which you pulverize it. If the stone begins to turn white, you must continue the same process until it turns very white. This will be from 500 distillations. If the fire diminish, and the operator be clever, knowing well the quantity of fire, from 450 distillations (the total is 900 distillations [emphasis added]), the stone, you may be sure, will have a complete and real whiteness. In this state you may operate for giving copper and iron a coating of silver. You can also operate on melted crystal, and pearls, and many other minerals, etc., etc.
Who was the first person to do this? What forgotten lunatic had the time, patience and fortitude to go to so much trouble for so little reward? Who would be so bloody-minded as to devote so much energy to such an odd pursuit?
And yet at the same time as I ask myself these questions, I find myself thinking of it as sort of wonderful. Alchemy is like a metaphor for human creativity. Haphazardly and yet remorselessly grasping for something which may, just possibly, be at least vaguely approaching good. Not to sound too pompous but sometimes when I am writing RPG materials I feel a little bit like Psuedo-Geber, waiting to see if the stone will begin to turn green.