Hearths in windmill towers

Why would the designers of a windmill bring fire into a mill? The benefits of a hearth must have been powerful, with the disadvantages including an increase of heat and potential for a destructive fire. In addition to requiring advanced masonry skills to incorporate a hearth, usually the flue passes over the machine slot, this created a void space at an already relatively weak part of the masonry tower. Other posts discuss windmill tower openings and windows in the windmill towers.

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Hearths characteristics and mills with them

The hearth was built into later mills and usually built into the northeast or southeast interior section of the mill in conjunction with a window. The flue then goes up and to the west within the wall of the mill, most often above the machine slot, exiting in the lee of the mill very near the top of the masonry cone. Hearths average about three feet wide, four feet high, and two feet deep. There are some interesting exceptions to these general rules. A feature of the windmill most likely used for lighting purposes was the incorporation of a hearth and flue.

Roots grow down through the flue of the hearth at the Prosperity mill Roots grow down the flue at the Prosperity mill. Sometimes, beehives find a home in the flue of a windmill hearth.

Hearths were found at 13 sites, and only three of these mills are depicted on the Oxholm map. The 13 sites with hearths include Becks Grove (PQ), Big Fountain (NA), Bodkin (NA), Boetzberg (EA), Cane Bay (NB), Cotton Grove (EB), Diamond-Keturah (CQ), Little La Grange (WE), Paradise & Downings (PQ), Prosperity (NB), River (PQ), Spring Garden (NA), and Two Brothers (WE). Oxholm only included windmills at Big Fountain (NA), Paradise & Downings (PQ), and River (PQ).

Manmade beehive sits in the hearth at the Cane Bay windmill. Manmade beehive sits in the hearth at the Cane Bay mill.

Hearths were likely incorporated in the mill for use when the mill was in operation. Hearths introduced an element of complete destruction by accidental fire in the most important structure on the plantation. After all, without the ability to crush cane, the plantation was crippled. Since raw cane was not exportable, spoiling within a couple of days of its being cut, the inability to crush cane would have made the plantation economically unviable. Moreover, the incorporation of a hearth meant the mill tower was structurally weaker, especially since the flue nearly always passed above the tall, narrow machine slot.

Window and hearth interior at River windmill, facing east The hearth at the River mill appears to hang above nothing, reflective that the working floor of this mill was lowered about 4 feet and then put back into operation.

Flue of the River mill The flue at the River mill is characteristic of most hearths, with the exit in one corner and not the direct center of the hearth.

Hearths to contain light-producing or cooking fires?

The purpose of the hearth has been ascribed to a variety of functions. Dash in “The Windmills and Copper Walls of Barbados” claimed hearths were used on Barbados to contain straw fires for light at night. Mills were in nearly constant operation during harvest time. Lighting the back side of the rollers would help enslaved laborers see to feed the second crushing of the cane between the center, king roller, and the bagasse roller. However, a straw fire would probably burn so quickly that it would have to be constantly refueled; perhaps another fuel was used instead. Large fires would have been impractical in these hearths given the relatively shallow depth & how precious fuel was to run the sugar factory. Perhaps torches or lanterns were placed there for light, as this would provide the necessary light while providing an outlet for the smoke.

Window, hearth, and machine slot interior at Little La Grange windmill, facing south Little La Grange hearth sits between the window and machine slot.

The argument for the hearth supplying light is bolstered by the configuration of the surviving mills. In nine of the thirteen mills surviving with hearths, the hearth is directly opposite the bagasse opening. This would place the fire, and therefore light, in direct line with the bagasse roller. This was a dangerous place since a person would need to make sure the partially crushed cane, which was riding on the king roller, was properly fed between the bagasse roller and the king roller. A fire in this location would illuminate the back side of the roller mechanism without casting a shadow in this important and dangerous place.

Two Brothers hearth at floor level & lined with bricks Two Brothers hearth sits at floor level.

Two of the mills with the hearth on the same side with the bagasse opening are Diamond-Keturah (CQ) and Two Brothers (WE). Both of these mills have elaborate basements and t-ramp entrances which suggest advanced masonry skills and a change in construction approach. The third mill with the hearth not opposite the bagasse opening is the fairy standard mill at Paradise & Downings (PQ). The fourth and fifth mills with the hearth not opposite the bagasse opening are Big Fountain (NA) and Spring Garden (NA), which are discussed below.

Hearth at the Paradise & Downings mill Paradise & Downings hearth positioned several feet above the floor.

Lewisohn speculates that cooking was done for the work crew, as they were likely working long hours in the mill (p.128). However, given the value of the mill equipment, it seems to make more sense that food would have been brought into the mill from outside to protect the mill from any fire which might get out of control such as a grease fire.

Window and hearth interior at Boetzberg windmill, facing east Boetzberg hearth sits between the machine slot and east-facing window.

Hearth exceptions to the rule

The hearth at Big Fountain (NA) is immediately opposite the main entrance. The flue from this hearth exits within the machine slot opening. This flue opening is also very small, suggesting that the fire did not emit much smoke. However, since this was one of the earlier windmills with a hearth, it may have been experimental and later designs addressing deficiencies in this layout.

Big Fountain hearth Big Fountain has a flue that rises from the center of the hearth, different from other mills.

The most unusual exception is the hilltop windmill at Spring Garden (NA). In this mill, a small, one cubic foot hearth is found at ground level in the center of the east interior wall, immediately opposite the main entrance. The flue leads straight up and apparently to the northwest. The flue must exit where a tree was found growing from the side of the mill, where an unusual bulge was clearly incorporated into the structure of the windmill. With a hearth this small and situated so low, it is difficult to conceive that it would have thrown off any useful light for operating the mill.

Juice trough opening and hearth interior at Bodkins windmill, facing north Bodkin hearth sits next to the juice trough opening instead of the more typical machine slot.

The presence of hearths present interesting questions about their purpose and genesis. The most likely problem they solved was providing light to facilitate constant operation of the mill, especially in the operating months in the winter when days are a little shorter. Inclusion of hearths would have required more advanced masonry skills, likely accounting for their absence in earlier mills.