An Introduction to Windmills

A report on our meeting held 16th October 2107

Our speaker Geraldine Mathieson has had a life long interest in windmills. She is currently a volunteer miller at Wrawby Mill in North Lincolnshire. Her talk told the story of windmills.

Since ancient times households have produced flour from grain using quern stones. Village mills were developed initially powered by water. Wind powered mills are a later development. It may have been the Crusaders who brought back windmill technology from the Middle East. Many early windmills were post mills and smaller than you might imagine.  Geraldine showed an illustration from the time showing how the miller could barely squeeze into the structure.

Geraldine said that by the 1700’s windmills were becoming larger and taller with timber clad towers.  These smock mills were either whitewashed or tarred to preserve the timbers. It is not surprising that “white mill” and “black mill” became common names.

Most mills had four sails as a cross structure in timber was familiar to carpenters. Geraldine described how John Smeeton FRS, active in the 1700’s and famous for his lighthouses, investigated the efficiency of wind mills and concluded that five sails was the optimum number. By this time a cast iron spider called a “Lincolnshire Cross” had been developed which could be designed for any number of sails. Millers’ experience however led them to prefer six to five sails as they could be balanced if one sail failed by taking off the sail opposite.

Geraldine went on to describe the four systems used to operate the mill. The winding gear, often aided by a small fan, turns the windmill into the wind. The striking gear alters the shutters in the sails to suit wind speed and can be done whilst in motion. The tentering gear maintains the gap between the stones, and the grinding gear turns one stone above another to grind the corn.

Our speaker then gave a quick review of some of Bridlington’s windmills. Geraldine was particularly impressed by the large mill that stood on Springfield Avenue. By studying the outside features shown on photographs she was able to suggest how many stones it could power and what additional equipment might be in use.  Externally she identified a “Lincolnshire Cross” and Cubitts patent sail gear.

Windmills however can only be used on about 100 days a year.  With the advent of cheap and powerful steam engines, the development of roller mills, and the railway network to distribute flour to a wide area, industrial scale mills were developed. One such was Joseph Rank’s mill in Hull, the largest in the country.

Those windmills that remain are thankfully being preserved. Geraldine offered Holgate Mill in York as a prime example.

The Prior Bro Garry Sunley asked Sarah Ryalls to give the vote of thanks.  She thanked Geraldine for passing on some of her deep knowledge of windmills, their history, and how they work.