the scale of the globe is 1:80.000.000 and its diameter is c. 11.2 cm. it weighs 134 grams. the north-south axis is vertical reflecting the ancient aristotelian way. its identical twin, the lenox globe intended to represent the earth in the center of an armillary sphere is a cast made of red copper. on the lower half of the da vinci globe, there is a red copper droplet that contains arsenic, a chemical substance that was prescribed by da vinci to be added to copper to maintain the red color of copper. leonardo da vinci, the inventor, writes in codex atlanticus page 1103 verso: “metti nella mistura il rame arso, ovvero la corrompi collo arsenico, ma sarà frangibile”. in english: “add to the mixture large pieces of copper or corrupt it with arsenic, but it will be brittle."