Charles Augustus Schmalcalder - Schmalcalder's Patent
CHARLES AUGUSTUS SCHMALCALDER
INVENTOR OF THE PRISMATIC COMPASS
Click on the image to the left to download a pdf copy of Schmalcalder's Patent
SAFETY WARNING! Green compass cards from the 1800s and their respective makers’ green labels stuck inside the boxes were dyed with arsenic, and are hazardous even to touch, as arsenic can enter the blood stream through the skin, as well as through inhalation or ingestion. Arsenic poisoning can have similar symptoms to cholera.