How to Use Sugar Refractometer : Quick and Dirty Guide

My first encounter with refractometer was a bit embarrassing. I was not alone though. All of my classmates felt the same because we thought of the same thing. And, that awkward moment turned into laughter. We all arrived to conclusion that the small contraption was a monocular. Who wouldn’t? It was a handheld device with adjustable eyepiece. Except, the lens which supposed to magnify distant images was odd. It was flat and slanted, forming a prism. It had a flap protecting the prism from dirt and scratches and perhaps breakage too due to accidental fall.