All our knowledge has its origin in our perceptions - Leonardo da Vinci

Nitre, vitriol, cinnabar, alum, salt ammoniac, sublimated mercury, rock salt, alcali salt, common salt, rock alum, alum schist, arsenic, sublimate, realgar, tartar, orpiment, verdegris.

Obstacles cannot crush me; every obstacle yields to stern resolve.

Having wandered some distance among gloomy rocks, I came to the entrance of a great cavern ... Two contrary emotions arose in me: fear and desire — fear of the threatening dark cavern, desire to see whether there were any marvelous things in it.