E. Howard Clock Co four pendulum Isochronal regulator designed by Hezekiah Conant. RR-76.
The E. Howard Clock Company of Boston, MA, manufactured this important clock in 1888 for Hezekiah Conant. The case is marked with a die stamp inside. The original order has been found in the Howard Company logbooks and indicates it was ordered on April 3, 1888, and delivered on November 30 of the same year. Pawtucket, Rhode Island's thread king, Hezekiah Conant, placed the order. Mr. Conant was charged $1,605 for this clock, which was an extraordinary sum. Considering that in 1888, a two-dial tower clock (or public clock) installed in a town meeting house or church steeple cost approximately $400. This is the E. Howard Clock Company's tour de force. Conant was a gifted mechanical designer and received a patent for this very unusual timepiece mechanism on August 23, 1887. This clock features an escapement design that incorporates four individual mercury pendulums. As a result, it is called an "Isochronal clock." The unique design of this clock, with its four pendulums swinging independently and the averaging process, was a significant advancement in clockmaking, leading to increased accuracy and precision.
Conant theorized that multiple, two or four, pendulums swinging independently on separate escapements, combined with having movements that were designed to take their averages, would be more accurate than a single pendulum clock. Conant claimed that the elimination of error is always in proportion to the square of the number of pendulums. This implies that a two-pendulum clock would reduce the error to one-fourth. Thus, four pendulums would reduce the error to one-sixteenth. The difficulty with this theory is how to take multiple pendulums and mechanically translate their independent impulses into a single mechanism. This is ingeniously done with a combination of averaging wheels and planetary gears.
The main dial of this clock is formatted in the traditional style. This large dial is divided into twelve hours; Roman-style numerals indicate the hours. Arabic numerals are used to mark the five-minute intervals at the top of each hour. The individual minutes are marked on the closed time track. This ring also serves as the seconds ring. Each second would be indicated by the long sweep second-hand mounted from the center arbor. Each pendulum is represented on the dial plate with a subsidiary dial that tracks its progress. Each pendulum features four mercury-filled canisters, and the rods are of different lengths. As a result, each will have a specific number of beats per minute. This clock features pendulums that beat 56, 58, 60, and 62 beats per minute. Each of these dials is marked to indicate the rate at which it is tracking. Internally, the dials are paired, and the averaging process begins. The result is recorded on the two smaller dials above the four individual seconds dials. The gearing is then designed to take these two averages and average them again. This end result is recorded by the sweep second hand on the main dial. European and American Government ships of the time used this averaging process extensively. Many ships were designed to carry multiple chronometers on board. The standard practice was to average their results to give the correct Greenwich time. This aided in calculating the vessel's longitude. Conant's first version of this clock was constructed by Tiffany & Co. in 1887. That clock is said to have had all four pendulums of the same length. As a result, the astronomers of the day believed that the pendulums would synchronize by overpowering each other. This was due to vibrations developing in the pendulum's airspace. Conant improved on that clock with this design by moving the weights to their dedicated weight channels and constructing the four pendulums of varying lengths.
This massive movement, constructed in brass, is a testament to the skilled artisans of the time. The framing features a single back plate. Ten large pillars, secured with screws, support the three sections of the front plate. These plates are line decorated, and the upper front plate bears the Maker's die Stamp, "E. Howard & Co. Boston." Five- and six-spoke wheels are driven by two large cast-iron weights, fitted into the cabinet in dedicated weight channels at the back of the case. These are accessible via doors on the sides of the case. The weight cords wind onto grooved barrels at the top of the movement. These are connected to great wheels with stop work and maintaining power. The train is constructed with three sets of planetary wheels, each set designed to deliver power to one of the four deadbeat jeweled pallet escapements. Two pendulums are mounted to the front of the movement, and two are mounted to the large movement mounting bracket at the back of the case. The fine regulation arrangement of the sweep second hand is mounted on the right side of the movement. This allows one to adjust the clock to the 100th of a second while it is in operation.
This custom-built case is constructed in oak and retains its original old oak finish. The finish is in excellent condition and has developed a warm and inviting tone. It stands approximately 8 feet tall, 34.5 inches wide, and 22 inches deep. Two glass doors at the front of the case allow access to the dial and the four pendulums. Four smaller glass doors on the sides of the case provide additional interior access. The bonnet door on the right can also access the sweep-second-hand micro-adjustment. Four wooden paneled doors on each side of the case provide access to the two large weights. The decorative elements incorporated into the case design include a combination of Art Nouveau and traditional features. The fluted columns are fully turned. All four terminate at the top with carved Corinthian capitals. This impressive clock has a lovely presence.
Hezekiah Conant from Pawtucket, Rhode Island, was a successful mechanical engineer and industrialist. His company, The Conant Thread Company, became one of the leading thread mills in the area during the late 1800s.
Hezekiah Conant was born in Dudley, Massachusetts, on July 28, 1827, as the fourth child of Hervey and Dolly (Healy) Conant. He attended local schools and paid his own way through college at Nichols Academy in Dudley.
Hezekiah grew up in rural Dudley, Massachusetts, farming in the summers and going to school in the winters. At seventeen, he moved to Worcester to work in printing, then joined a local machine shop, where he became interested in mechanical drawing and started studying mechanical engineering. He soon became a talented engineer and inventor. Around 1852, he invented and patented a pair of "lasting pinchers" for shoemakers, though he did not profit from it. He worked in machine shops in Boston and Worcester before moving to Hartford, Connecticut, where he worked for gun makers like Colt’s Firearm Manufacturing and Christian Sharp, the inventor of the Sharp rifle. In 1856, he invented and patented a "gas check" improvement for the Sharps rifle, which was so important that both the U.S. and British governments ordered it for all Sharps rifles they bought. That same year, he built a machine for Samuel Slater & Sons in Webster, Massachusetts, to sew the selvage on doeskins. Although he did not patent this device, it was very successful and is still used. Conant then focused on improving thread manufacturing machinery, inventing a machine for dressing sewing thread and an automatic machine for winding spool cotton, both of which he patented. The Willimantic Linen Company was so impressed that they bought half the patent rights and hired Conant as a mechanical expert in 1859. He also invented a 'ticketing machine' that could cut, gum, and apply labels to both ends of thread spools at a rate of 100 per minute. In 1864, he traveled to Europe for his employer to study major thread factories, including J. & P. Coats and the Clark works in Paisley, Scotland. When he returned in 1865, he became superintendent of the Willimantic Linen Company until 1868, during which time the company doubled its capital and production.
In 1868, Conant left the Willimantic Linen Company and moved to Pawtucket, where he started the Conant Thread Company with $100,000 in capital. He served as both treasurer and manager. He also maintained his relationship with J. & P. Coats of Paisley, Scotland, the world’s top threadmaker. Conant’s company grew to employ over 2,000 people and was known as one of the best-run and best-equipped thread mills anywhere. By 1893, the business covered about forty acres and had more than $4 million invested. The company was also known for paying good wages.
Conant was also active in other areas. He served as president of the Pawtucket Institution for Savings, president and director of the Pacific National Bank, vice president of the Pawtucket Safe Deposit Company, and director of both the First National and Slater National banks in Pawtucket. He was a major supporter of Nichols Academy, where he helped build new school buildings, dormitories, an observatory, and a library with a reading room.
Mr. Conant was married three times. His first wife was Sarah Williams, daughter of Col. Morris and Elizabeth (Eaton) Learned; they married on October 4, 1853, and she died on July 17, 1855. In November 1859, he married Harriet Knight Learned, Sarah’s sister, who died on July 6, 1864. On December 5, 1865, he married Mary Eaton, daughter of Dr. Samuel P. and Harriet (Eaton) Knight.
Hezekiah Conant died in Pawtucket, Rhode Island, on January 22, 1902, at age 74. He is buried in Corbin Cemetery in Dudley, Massachusetts.
Inventory number RR-76.
The E. Howard & Company represents a significant chapter in American horological history, continuing the legacy of the esteemed Howard & Davis firm after 1857. Established in 1842 in Roxbury, Massachusetts, Howard & Davis was the brainchild of Edward Howard and David Porter Davis, both of whom trained under the legendary Aaron Willard Jr. Their early work set new standards for precision timekeeping and craftsmanship in 19th-century America. The firm’s innovations extended beyond clocks to include balances, sewing machines, fire engines, and watches—demonstrating a remarkable breadth of technical achievement. By 1852, their manufactory was a landmark in Roxbury, as seen on period maps. Following the dissolution of Howard & Davis, Edward Howard’s vision propelled him to become Boston’s leading maker of weight-driven clocks, catering to both residential and commercial needs. Notably, the company played a pivotal role in shaping the landscape of American tower clocks and advanced timekeeping systems during the late 1800s, contributing to the growing network of public and institutional clocks across the country. The completion of a new factory complex in 1873 further cemented their influence, with separate facilities for clocks and watches reflecting the scale and ambition of their operations.
The legacy of the E. Howard Clock Company endures as one of the most respected in American horology. Renowned for its unwavering commitment to quality and innovation, the company never produced an inexpensive clock; instead, it set benchmarks for accuracy, durability, and elegance. Its clocks became the standard in schools, public buildings, and railway stations across the country, marking significant moments in the nation’s growth. Collectors and institutions alike prize Howard clocks for their superior craftsmanship and historical importance. Today, the E. Howard name remains synonymous with exceptional quality, technical achievement, and an enduring influence on the art and science of clockmaking.
