He was a skilled lens grinder, making excellent telescopes and small, short focus, simple microscopes, and he seems to have learnt these techniques during the time he lived with Galileo . Gliozzi writes in:
Siya ay isang mahusay na lens gilingan, paggawa ng mahusay na teleskopyo at maliit, short-focus, simple microscopes, at siya tila sa may learnt mga pamamaraan na ito sa oras ng oras siya nanirahan sa Galileo. Gliozzi magsusulat sa: