Prove It from the Text

How Braille Was Invented

Louis Braille was blinded in an accident at the age of three. At his school, blind pupils read by tracing raised letters pressed into paper. It worked, slowly — a fingertip cannot take in a whole letter shape at once — and nobody could write that way at all. When Braille was twelve, a soldier visited the school with a code of raised dots that soldiers used to read messages in the dark. It was too complicated, but the idea of dots was right. Braille spent three years simplifying it. He settled on a cell of six dots, small enough to sit under one fingertip. He was fifteen when he finished. He was forty-three when he died, and the system was not widely accepted until after that.

Turning Milk into Cheese

Cheese begins as an accident that people learned to repeat. Milk is mostly water with fat and protein in it. To make cheese, the protein has to be separated out. A starter culture of bacteria is added first. The bacteria turn some of the milk sugar into acid, and the acid begins to make the protein clump together. Then rennet is added, which finishes the job. The milk splits into solid curds and watery whey. The whey is drained off. The curds are pressed, salted, and left to age. Time does the rest: a cheese aged for two years tastes nothing like the same cheese at two weeks.