In the middle of the nineteenth century a farmer in that neighborhood, Joseph Harding of Marksbury Vale, systematized the manufacture and it was his method that became the model for cheesemaking in America. In this country it was first made in Herkimer County, N.Y., where Harry Burrell not only made cheese for the home market, but also exported to England, and his son, David H. Burrell, at Little Falls later developed the machinery which became the standard for the American and Canadian cheese factories. The factory system by which cheese was made from milk brought together from several farms, originated near Rome, N.Y., and soon cheesemaking became an important industry throughout Central and Northern New York whence it spread into Pennsylvania, Ohio and the West, as well as to Canada. To-day Wisconsin makes more cheese than all the other states together and Canada largely supplies England with Cheddar cheese of excellent quality. [Illustration: Joseph Harding, who systematized the making of Cheddar cheese in England ] [Illustration: David H. Burrell, who introduced laborsaving machinery and supplies in the cheese factories ] [Illustration: Jesse Williams, father of the American factory system ] _The Factory System_ The milk is delivered in the morning by the farmers at the factory and is weighed and strained through cheese-cloth into the cheese vat. When it is all in the vat it is warmed to a temperature of 86° F. by letting steam into the water surrounding the bottom and sides of the jacketed vat. [Illustration: A measuring glass and an accurate thermometer are indispensable ] [Illustration: The Marschall rennet test ] =Ripening.=—The milk should be slightly acid, not noticeably sour, yet sufficiently ripened for the proper fermentation to take place in the process that follows. The best cheesemakers regulate the ripening by adding a starter to the sweet milk and allowing the lactic acid bacteria to multiply in the milk until a _Rennet Test_[6] or _Acid Test_[7] shows that the desired degree of acidity has been reached. The starter may be sour whey or preferably prepared from sweet skim milk or whole milk with a commercial lactic acid culture as described in Chapter I under _Ferments_ and _Buttermilk_. From 1% to 2% starter is usually sufficient. An acidity of .18% to .20% or 2½ degrees on the Rennet Test is usually desired before the rennet is added. [Illustration: Christian D. A. Hansen, inventor of commercial rennet extract ] [Illustration: Blowing up the rennets to dry them ]