The ice cube on f102v

[Jorge_Stolfi]

On folio You are not allowed to view links. Register or Login to view. one can see a curious  [brick-shaped] object placed between several plants: It seems out of place. I will call it "the ice cube". What could it be?

   

This is a crystal of copper sulfate pentahydrate, CuSO4.5H2O, aka "blue vitriol".  (I grew it by accident -- I used the stuff to prevent fungus growth on a trimmed tree, and forgot the leftover solution in a corner of my workshop.)  

Crystals of this compound, and of the similar iron(II) sulfate, aka "green vitriol", were collected since antiquity from puddles on the floor of old copper mines.

Now I should tell you which book lists "blue vitriol" as a remedy.  But I cannot.    

(Although I am just pulling your collective legs, because I don't believe that the colors of the VMS illustrations are original.  So that "brick" could indeed be any drug that can be pressed and traded into brick-like blocks.)

All the best, --stolfi