Hypatia was a Greek mathematician, astronomer, and philosopher who invented the hydrometer in about 400 AD. Described as a charismatic teacher, she was seen as an evil symbol of the pagan science of learning and she was eventually murdered by Christian zealots. For many women in years gone by, the invention process was fraught with danger and difficulty. Not only did they face the hardship and obstacles of inventing, they also had to contend...