Until 1875, all chocolate has been what we now call plain or data chocolate. It was also coarse and gritty. Then, two separate developments happened in Switzerland. Henri Nestlé was experimenting with condensed milk for breakfast cereals when his partner, Daniel Peter, suggested adding condensed milk to chocolate. By doing this, they invented milk chocolate. Four years later, Rudolph Linda invented the "conche" , a machine with rollers that moved backwards and forwards over the chocolate. The movement created friction and heat that broke down even the tiniest crumbs. The result crumbs. The result was chocolate with a smooth, velvety texture.