The mills at Wicksbridge are imaginary, but their planning, construction, and operation are quite typical of mills developed in New England throughout the nineteenth century.
About the Author
David Macaulay is an award-winning author and illustrator whose books have sold millions of copies in the United States alone, and his work has been translated into a dozen languages. Macaulay has garnered numerous awards including the Caldecott Medal and Honor Awards, the Boston Globe–Horn Book Award, the Christopher Award, an American Institute of Architects Medal, and the Washington Post–Children’s Book Guild Nonfiction Award. In 2006, he was the recipient of a MacArthur Fellowship, given “to encourage people of outstanding talent to pursue their own creative, intellectual, and professional inclinations.” Superb design, magnificent illustrations, and clearly presented information distinguish all of his books. David Macaulay lives with his family in Vermont.
Read an Excerpt
The Yellow Mill
On February 27, 1810, a partnership was formed in Providence, Rhode Island, for the purpose of building and operating a cotton mill. The older partners, who knew almost nothing about setting up such a mill, included Silas Wicks, Zenus and Sylvanus Chaney, and Judge Pardon Fiske. Wicks and the Chaney brothers had amassed considerable fortunes in shipping and foreign trade; Fiske's wealth came from farming. The youngest partner, twenty-seven-year-old Zachariah Plimpton, had grown up in England and knew a great deal about cotton textile manufacture. At the age of fourteen, he had been apprenticed to a prosperous mill owner and for the next eight years had worked in every area of cotton spinning, weaving, and factory management. He came to America at the age of twenty-two to escape an arranged marriage and soon found work as an agent, managing a small Rhode Island mill. The subsequent success of that mill established Plimpton's reputation as one of the ablest men in the business.
At their first meeting, each partner took responsibility for a particular aspect of the new venture. Wicks and Judge Fiske would pay for the machinery and initial supply of cotton. The Chaneys were to provide the materials, workers, and money to build the mill. Plimpton was to design and supervise the construction of the mill and to act as its agent when it was finished. At his suggestion, the partners agreed to operate about seven hundred and fifty spindles for spinning cotton and to run all the machinery with water power.
Plimpton soon compiled a list of available mill sites, and on Monday, March 19, he set off to choose the best one. The requirements that concerned him most were access to a river for power and to a road or canal for transportation. At each location he first estimated the river's flow, and determined the highest available head.
Plimpton carefully recorded his findings and, after comparing a number of possibilities, chose a piece of property on the Swift River about half a mile below the falls. Included with the land was the valuable mill privilege that permitted the owner to divert a percentage of the river's flow to power one or more new mills. Between the top of the falls and the beginning of the property, the river dropped almost thirteen feet. Along the rapids immediately adjacent to the site, it dropped another five.
On his return to Providence, Plimpton set about designing a water wheel that would use the river's power most efficiently. He calculated that by building a dam across the rapids he could create a six- or seven-foot head without affecting the mills upstream. After comparing the power from each type of wheel with the needs of the machinery, he settled on a breast wheel. Like the overshot wheel, it was turned by the weight of the water in its buckets, but it did not require as great a head. Instead of coming over the top of the wheel, water entered the buckets of the breast wheel from the upstream side and turned in a direction opposite to that of the overshot wheel. Plimpton saw this as a great advantage in times of flooding. The higher the water level in the river, the more chance there was of it backing up into the wheelpit and decreasing the efficiency of the wheel. Because of its direction of rotation, the breast wheel would tend to push the backwater away, whereas the overshot wheel would draw it underneath itself and further reduce its efficiency.
The floor of the wheelpit on the upstream side was carefully formed to follow the circumference of the breast wheel. This curved section of floor, called the breast, left so little space between itself and the wheel that the water was kept in the buckets until they had reached the lowest point in their rotation. Because water entered the buckets midway up the height of the wheel, the wheel Plimpton designed was called a midbreast wheel.
Although he could plan the mill based on the amount of machinery it had to house, Plimpton could not determine its precise dimensions without first designing the power train. The rotary motion of the water wheel was transferred to a vertical shaft through an arrangement of bevel gears. Through an additional set of bevel gears, the rotation of the vertical shaft was transferred to a horizontal shaft called a line shaft. Each machine was connected to the line shaft either by a small vertical drive shaft or by a continuous rope or leather belt.
After determining the length of the longest line shaft, Plimpton decided on the length of the building. The width was established by first laying out the machinery along the line shafts and then placing the walls as close to it as possible, in order to let the most daylight into the work space.
Because of its availability, wood was the most practical building material. Since most of his experience in England had been with brick and stone construction, Plimpton hired a millwright named Benjamin Quigg to design the building's timber frame and to supervise its eventual construction.
In early April, Plimpton presented the plans to his partners. The mill was to be sixty-four feet long by thirty-four feet wide, with two full stories and a usable attic. While comparatively large windows would serve the lower floors, two narrow strips of windows, called trapdoor monitors, one on each side of the roof, would let light into the attic. At one end of the building, he had placed a small projecting shed to house the wheel. On the peak of the roof at the other end, he had designed a simple cupola to house the bell.
They were all delighted with Plimpton's efforts and urged that construction begin as soon as possible.
After calculating approximately how much timber would be needed for the siding, roofing, and flooring, Quigg went to a number of saw mills near the site and bought all the well-seasoned wood he could find. Plimpton remained behind to order such items as window frames, glass, nails, tools, and various cast-iron pieces, which were to be manufactured in the Providence area.
Two days later, Plimpton joined Quigg at the Eagle, a tavern near the falls. Both men rented beds there for the duration of the project.
The following morning, Quigg began felling trees he had already marked for the main frame of the building. Plimpton, meanwhile, made arrangements with a local farmer to quarry stone for the foundations and wheelpit from an exposed ledge on his property.
Two weeks later, close to a dozen men, most of them itinerant laborers lodging at nearby farms, were quarrying stone and loading it onto sleds.
While others hauled the trees that Quigg had cut, a third group prepared the site and cleared an area where the various materials could be stored.
Before establishing the precise course of the raceway and the location of the wheelpit and mill, Plimpton checked for any hidden boulders and ledges that could delay excavation. Satisfied that no major obstacles lay concealed, he then staked out the various holes and trenches and excavation began. By the end of May, the tailrace was finished. It had been dug first in order to drain any seepage that might enter and hamper the digging of the wheelpit.
Plimpton lined the bottom of the wheelpit with a wooden floor, to speed the departing water by reducing friction and to prevent the water from washing out the soil under the side walls. The breast was then secured to the floor and to the walls. After setting each curved timber rib into place Quigg tied them together with a layer of thick planks. The space inside the breast was filled with rock and gravel. Before Quigg nailed down the last plank, Plimpton indulged his superstitions and slipped a coin behind the face of the breast for good luck. It was a Roman coin he had discovered in England when digging his first wheelpit.
In early August, when the level of the river was at its lowest, Quigg turned his attention to the construction of the dam. It would consist of two identical wooden ramps projecting slightly upstream from stone abutments on each bank. The two would cross the lower rapids and meet in the center. Each ramp would reach a height of six feet and taper back about twenty-five feet. Workers assembled the pieces of the framework on the banks, but before they could be moved into place the riverbed had to be drained. This was done a section at a time, using a temporary dam called a coffer dam. It extended from the bank to about the center of the river and consisted of large wooden baskets dragged into position and sunk with rocks. Clay was packed between them to seal the barrier further.
When the water below the coffer dam had drained away, the loose rock and rubble were cleared and a number of heavy timbers were set into trenches cut in the riverbed and pinned in place with iron rods. The frames were then secured to the timbers and connected by crosspieces. After filling the space inside the frame with rocks, Quigg covered the dam with a layer of planks. The combined weight of the water and the rocks would hold the dam in place. On the top or crest of the dam, Quigg secured a caplog to reduce wear on the ends of the planking. When the first half of the dam was completed, the coffer dam was removed and the process repeated on the other side of the river.
While the dam was under construction, much of the headrace had been dug and lined. Several feet of embankment at the entrance to the headrace were not excavated, to prevent water from entering the channel until all work in the wheelpit had been finished.
From a point in the headrace near the wheelpit, Plimpton dug a smaller channel called a spillway. It would be used to drain the headrace for repairs and as a safety precaution in times of flooding.
By September the stonework was complete and most of the timber for the building had arrived. While the planks were being cut at the saw mill, Quigg and a few skilled assistants had hewn each post and beam to its required shape and size.
Many of the pieces were to be fastened together using a system of tenons and mortices. Tenons are projecting wooden tongues that are precisely cut to fit into matching slots called mortices. Each connection was then to be secured with a wooden dowel called a treenail. The tenons, mortices, and treenail holes were all cut or bored and checked for fit before assembly began.
On its completion, the foundation was capped with heavy beams called sills. Notched into the sills and spanning the width of the foundation was a row of parallel floor beams, the centers of which rested on stone piers. Smaller beams, called joists, connected the main beams and supported two layers of one-inch-thick floor planks.
The main structure of the building was to be a row of thirty-foot-wide parallel frames locked together by sturdy horizontal beams. The space between each frame, called the bay, measured roughly seven and a half feet. Starting at one end of the floor, the frames were assembled and then left lying approximately where they would stand.
On the evening of August 31, as the last pieces of the end frame were being fastened together, a mud-splattered coach pulled into the yard behind the Eagle. Plimpton was there to welcome Wicks and the two Chaneys, who had come to watch the raising of the frame the following day.
By the time Wicks and the Chaneys arrived at the site early the next morning, over a hundred and fifty men, women, and children from the surrounding farms had already gathered. While some farmers had refused to help build a factory in their rural area, others were only too pleased to help create a new market for their agricultural products and various skills.
As soon as the visitors were settled, Quigg gave the order to raise the first frame. This was done slowly and carefully using ropes and pulleys attached to a temporarily secured vertical timber called a gin pole. The tenons below each post were gently guided into their mortices in the sill. Once the frame stood straight, it was held in place while the frame adjacent to it was raised using both the gin pole and individually held poles called pikes. Both frames were then connected at the second-floor level by two horizontal beams called girts and at the attic level by two more horizontal beams called plates. The plates were locked in place by beams that ran across the width of the mill and tied the end posts of each frame together. Diagonal bracing was used to secure the structure further. This process was repeated down the length of the building, and by late afternoon the entire skeleton stood assembled.
No sooner had the last peg been driven into place than the entire group broke into a loud, spontaneous cheer. Shortly thereafter a spirited party began, which didn't end until all the food and drink had been consumed. It was close to one in the morning before the last workers wandered back to their respective barns and farmhouses.
By the time Plimpton arrived at the site the following Monday morning, a portion of the structure had already been enclosed by heavy vertical planking and Quigg was clambering around, supervising the construction of the second floor.
When the attic floor was finished, pieces of the roof frame were hoisted onto it, assembled, and raised. When the entire frame was complete, it was covered by a layer of planking followed by a layer of overlapping wooden shingles. As each wall of vertical planking was completed, it was sealed by overlapping horizontal boards called clapboards and painted yellow.
The interior surface of the vertical planking was covered by narrow strips of wood called lath, to which a thick coat of plaster would be applied once the window frames had been installed.
While Quigg had been supervising the construction of the building, Plimpton had been concentrating on the wheel. It had to fit into the pit as closely as possible, so the size and shape of each piece was double-checked before being cut. The heavy timber shaft that would carry the weight of the wheel was shaped first. The spokes were cut next and fitted into slots around each end of the shaft. Both rims of the wheel, comprised of thick segments called felloes, were then constructed to tie the ends of the spokes together. Plimpton had a series of carefully measured grooves cut into the inside faces of the felloes to receive the boards that would serve as the fronts of the buckets.
An iron extension called a gudgeon was wedged into grooves at each end of the shaft and secured by iron bands. The projecting cylindrical ends of the gudgeons, called journals, were to revolve in cast-iron bearings. Each bearing was lined with bronze to reduce friction and secured to one of the beams on each side of the wheelpit. Once the shaft had been set in place and leveled, workers inserted the spokes and secured the rims.
The space between the rims was then enclosed by a continuous barrel-like surface of planks called the soaling. The soaling not only tied the sides of the wheel together but also served as the back of each bucket.
The last pieces of the wheel to be assembled were the bucket faces. Before each board was slipped into its grooves, two small holes were drilled through each one and covered on the inside by leather flaps. These acted as valves, which would automatically close as water entered each bucket. They would open again as it left, preventing the formation of a vacuum in the bucket as it rose from the wheelpit. A vacuum would hamper the exit of the water and in turn retard the rotation of the wheel.
When the wheel was finished, the entire pit was enclosed by the wheel house.
Between the end of the headrace and the wheelpit, a pair of wooden gates was installed to control the amount of water entering the buckets and thus the speed of the wheel. A screen of closely spaced inclined wooden strips, called a trashrack, was placed across the headrace just in front of the gates to prevent debris that might damage the wheel or breast from entering the pit.
In early October, the upper end of the headrace was excavated and lined. Across the entrance, Plimpton floated a log called a trash boom. It was secured to both banks and protected the headrace from larger pieces of floating debris.
While the shafting for the power train was to be wood, the gears were to be cast iron. The first gear had already been installed in segments inside the rim of the water wheel closest to the building. Its teeth, which faced the horizontal wheel shaft, turned a smaller gear called a pinion.
The pinion was attached to a second horizontal shaft that extended into a space below the floor of the mill. At the opposite end of this shaft was a large vertical bevel gear. The teeth on its angled rim were designed to mesh with those on a horizontal bevel gear at the base of the vertical shaft.
Both the vertical and horizontal shafts were built of sections fastened end to end. This made the shafting easier to install, and easier to repair. A square bar of iron was set into the end of each section of shaft. Two bars were then joined using a square cast-iron sleeve called a coupling. A journal was cut into each iron bar so they could rotate in their bearings.(Continues…)
Excerpted from "Mill"
Copyright © 1983 David Macaulay.
Excerpted by permission of Houghton Mifflin Harcourt Publishing Company.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.
Table of Contents
The Yellow Mill,
Excerpts from the Diary of Zachariah Plimpton,
Excerpts of a Letter from Selinda Sparrow,
Excerpts from the Diary of Zachariah Plimpton,
The Stone Mill,
Excerpts from the Diary of Zachariah Plimpton,
Excerpts from the Diary of Ephraim Dodge,
Excerpts of a Letter from Betsey Oliver,
Excerpts from the Diary of Ephraim Dodge,
Excerpts from the Diary of William Plimpton,
The Plimpton Mill,
Excerpts of a Letter from Dora Sullivan,
Excerpts from the Diary of Alonzo Humphrey,
The Harwood Mill,
About the Author,
What People are Saying About This
"Well-researched, ambitious, and absorbing, this is another first-rate history lesson from a practiced, perfectionist hand." Booklist, ALA, Starred Review
Most Helpful Customer Reviews
Mill is a pretty good book. It explains how mills were built, and how they operate. I give this book four stars because it was interesting, but I would rather it be more interesting in a kids point of view.