As a random aside, he also includes a proof that the water level mechanism he prefers works even though the Earth is a (roughly) spherical object and not a flat plane.
For when lead is smelted in casting the fumes from it settle upon their members and day after day burn out and take away all the virtues of the blood from their limbs Hence water ought by no means to be conducted in lead pipes if we want to have it wholesome That the taste is better when it comes from clay pipes may be proved by everyday life for though our tables are loaded with silver vessels yet everybody uses earthenware for the sake of purity of taste.
Google books, pg 246 https://goo.gl/g19bhQ