On August 13, 1863, the first commander of the new arsenal, Major Charles Kingsbury, arrived to superintend construction of the storehouse. The U.S. Army Ordnance Department had already done much of the planning. A Board of Officers had selected the site, 300 feet from old Fort Armstrong, and the Chief of Ordnance had determined that the building material be Le Claire limestone, a buff-colored dolomite, from a quarry fourteen miles upriver from the Island. Major Kingsbury brought with him plans for Storehouse A which had been designed and drawn up in Washington, D.C., at Ordnance Department Headquarters, and which were identical to plans for the buildings at Columbus and Indianapolis.

Plans called for a brick or stone building suggestive of the classical Greek revival architecture popular among public buildings at the time. The main building was 180 by 60 feet, three stories high, in addition to a full basement and attic. The portico, 14 by 60 feet, extended from one of the long sides. In the center of the opposite side stood a 34-foot square, 97-foot high tower. This tower would house a clock and serve as the main hoist to the three stories.

During the fall and winter of 1863-64, Major Kingsbury hired a master builder and work crew, contracted for the LeClaire stone, and supervised excavation of the basement. Tracks were laid from the river to the building site and around it so that stone could be delivered where needed. Additional tracks circled the inside walls. On these a builder's derrick moved from place to place.

On April 12, 1864, the cornerstone of the Clock Tower Building was laid. Major Kingsbury placed copies of local newspapers, a 50-cent piece captured in Sherman's raid, and a list of names including President Lincoln, Governor Richard Yates of Illinois, and others, in a tin box. The box was placed in a hollowed stone and cemented in place at the northwest angle of the foundation. This cornerstone was searched for in 1966 as part of the Centennial of the Rock Island District, but it has never been located.

Soon after the laying of the cornerstone, Major Kingsbury ran into a series of problems. Wartime inflation reached 30 percent in 1864, increasing the cost of already scarce supplies. A shortage of laborers slowed construction.

The stone contractor fell far behind in his delivery of stone and eventually refused to ship any more stone at the contracted rate. By the time he had bargained for a better contract, the Mississippi River had fallen to the lowest level in history, making delivery impossible.

Growing frustration over the slow pace of work led to Major Kingsbury's resignation in June of 1865. Storehouse A was not yet up to the first story.

His replacement was General Thomas J. Rodman, already well-known as the inventor of the Rodman Gun. The appointment of an officer of such high caliber heartened area residents, because it indicated that the Ordnance Department had selected Rock Island as the site of a major arsenal - the "Harper's Ferry of the West."

General Rodman brought with him plans for a greatly expanded Rock Island Arsenal and assurances of support for those plans. The Clock Tower Building as it stands today reflects much of General Rodman's vision. Where Major Kingsbury's requests to alter the plans of the building were denied, the even greater departures of General Rodman were all granted.

He added rustication above the windows and arches, extended the roof cornices, and put balustrades at the top of the tower. He replaced the hip roof with a gable roof to provide ventilation for the attic.

The main building was finished by the summer of 1867. A force of as many as 400 men had worked on it.

The tower was built last, during the summer and fall of 1867. It rose 117 feet - 20 feet higher than the plans called for. Hoisting apparatus extended through the first five floors, with access for horse and wagon through arches at the ground level.

On the sixth floor General Rodman installed the clock that has become the symbol of the building. Its four 12-foot faces are twice the size called for on the plans. Original Ordnance plans called for a more modest clock with six-foot faces chiseled into the stone surfaces of the tower.

General Rodman selected the nationally known A. S. Hotchkiss Company of Williamsburg, New York, to build the clock. Mr. Hotchkiss not only designed and built the clockworks at his Williamsburg shop, he brought them to Rock Island on December 30, 1867, to personally assemble and install them.

The clockworks sit today where they were installed in 1868, along the east wall of the sixth floor of the tower, in a solid frame of cast iron 7 feet, 9 inches long, supported by four iron columns.

The Hotchkiss clock is impressive to see close up. The time main wheel, 3 feet in diameter, revolves once in twelve hours. It has the hours painted on its face, with a pointer denoting the hour of the day. The second wheel, 27 inches in diameter, revolves every hour. Minutes are painted on its face with a pointer denoting the minute of the hour. The second wheel also has a lifting pin attached to unlock the striking mechanism.

The escape wheel, 8½ inches in diameter, revolves in three minutes and has the seconds pointed off. The arrangement of wheels and numbers precludes the necessity of any dial work on the movement.

The escape wheel has 30 pins of a special shape designed by Mr. Hotchkiss to prevent oil being attracted to the wheel. This leaves the pins dry and solves one of the main problems of pin escapements. The pallets are of agate, with both pins and pallets having a high polish.

The main strike wheel has 32 steel rollers for raising the hammer. All of the wheels in the works are of bronze (gun metal); the journals or bearings are bossed with the same metal. The pinions are made of steel, while the wheels used for winding the clock are of engine-cut and polished iron.

A system of rods and gears running from the clockworks to the center of the room, and from there to the four dials, runs all four sets of clock hands simultaneously.

Each of the 12-foot wooden clock faces forms a "porthole" in one wall of the tower. Around the center of the dial in a six-foot circle are twelve round glass windows at the hour points. Near the edge of the dials an arrangement of "stars and bars" marks off the hours, with stars representing the hours of 3, 6, 9, and 12, and bars representing the remaining hours. At the very edge of the dial, small raised bars mark off the minutes. Dials, markings, and carved hands are all of wood, with hands and markings painted white to set them off from the black dial.

An observer looking out the windows in the dial can watch the hands visibly move with each tick of the clock.

The pendulum hangs down through two stories of the tower, its wood shaft and 350-pound ball vibrating every three seconds. Its length to the center of oscillation is 29 feet, 6 inches, giving a whole length of nearly 32 feet.

Power to operate the clock comes from weights suspended by wire ropes from an 18-inch spiral-grooved drum in the clockworks.

A 1,200-pound weight, at the end of a wire rope 250 feet long, creates 250 pounds of tension to operate the striking mechanism.

A 1,000-pound weight, at the end of 150 feet of wire rope, creates 150 pounds of tension to drive the time mechanism.

By January 20, 1868, Mr. Hotchkiss had the clock in perfect order. The works were enclosed in a wood and glass case by the head carpenter at the Arsenal.

Mr. Hotchkiss adjusted the clock to keep local time, the actual sun time on the Island. Nearly all of the businesses in the surrounding towns kept "Chicago time," also called "railroad time," because Midwestern railroads ran by it. Uniform time zones were not established until 1883; in 1868 there were more than 100 time zones in the United States. The result was that the Clock Tower clock ran between 12 and 15 minutes behind most other clocks in the area.

General Rodman's dealings with the clockmaker were very satisfactory. The contract for the clock came to $5,000. Mr. Hotchkiss supplied the works, all weights, wire rope, all hands, pulleys, hammers, and gearing for the dials. He paid all the freight bills to the Arsenal and personally installed the clock at no additional expense. He also warranted his work and all the parts.

The bell for the clock was bought from Fairbanks & Co., New York, and manufactured by E. A. & G. R. Meneely of West Troy, New York. It weighed 3,538 pounds and cost 47 cents per pound, or $1,662.36.

Residents complained that the bell was too loud, and it was eventually disconnected. In 1945, when the clockworks were extensively overhauled, the bell was reconnected at the lowest possible level -so faint that it can seldom be heard inside the building.

Originally the Clock Tower clock was wound by hand, a job that took two men twenty minutes once each week. On the walls of the clock room, among a number of unofficial names and dates of times when repairs were made, is an entry dated July 7, 1907, which reads: "Carrie Passig and daughter Ruth and Hattie Pratt came with Papa (W. J.) Pratt to see him wind clock. Papa started to wind clock in 1867 and missed winding three times in 1867 to 1907."

In 1950, on an experimental basis, the clock was switched over to electric winding. In 1955, an electric motor and gears were installed permanently. Otherwise, the clock still has all its original parts.

The Hotchkiss clock has lived up to its reputation. It is the only known clock of its type still running. From the first, it has only lost or gained an average of 15 seconds per week in good weather. Snow and ice occasionally slow or jam the hands in winter, but seldom for long. It has faithfully noted the minutes and hours of more than a hundred years of American history.

With installation of the clock and bell, the building was complete. Its three main floors provided 35,000 square feet of storage space capable of supplying arms and munitions for 150,000 troops. All three floors were open, except for two rows of cast iron columns on the first and second floors. The third floor was completely open, its ceiling suspended from trussed roof beams in the attic. Two interior hoists supplemented the main hoist in the tower.

Given its utilitarian purpose, the interior of the Clock Tower Building was finished handsomely. Roof beams, girders, and floor joists were all of white pine. Floors were of Indiana white oak. Ceilings were plastered and painted, as were the wainscoted walls. Stairways of oak and walnut ran up the north wall of the tower and each end of the portico.

The Clock Tower Building rests on foundations four feet deep. The walls of the first story are three feet thick; above that the walls are two and one-half feet thick.

Even before the building was finished, however, General Rodman's plans for the Rock Island Arsenal were taking shape further toward the middle of the Island. He ordered the tracks of the Chicago, Rock Island, and Pacific Railroad moved from the site of the first bridge across the Mississippi River to a location just west of the Clock Tower Building. During 1869, much of the land around the building was scraped away to provide fill for this new railroad embankment, leaving the building one and one0half feet higher than before.

Although the Clock Tower Building was used for the storage of arms and supplies until World War I, it was never part of the main Rock Island Arsenal. Shortly after World War I it was ordered torn down. It was saved in response to local sentiment, but it was kept chiefly as a relic.

In 1930, Congress authorized the 9-foot channel project on the Upper Mississippi. Responsibility for much of this project was given to the Rock Island District, Corps of Engineers, who soon found themselves cramped for space on the second floor of the Federal Building in Rock Island. In 1931, a Rock Island District field construction office moved into the first floor of the Clock Tower Building to supervise the first work on the project, the construction of locks and Dam 15, a few hundred feet away.

District employees made use of the new luxury of space to install a rifle range and a golf driving range in the attic, and a basketball court on the open third floor. These were soon replaced by additional "temporary" offices from the crowded Federal Building.

Since Storehouse A had never been intended for anything but storage, much renovation was necessary. There were no permanent partitions, no provisions for heating or ventilation, no running water, and no passenger elevator. In a flurry of activity, often around the clock, in 1934, partitions were built, tile floors laid, and heat, water and electricity installed. On December 10, 1934, the District Engineer, Colonel R. A. Wheeler, officially moved his office to the Clock Tower Building.

On September 6, 1941, the Clock Tower Building and a surrounding 6.9-acre triangle of land was transferred from the Ordnance Department to the Corps of Engineers, making the Rock Island District one of only three Engineer districts which have their own buildings.

A visit to the Clock Tower Building today will show how well the District has settled in. Modern duplicating, printing, and photography equipment fill much of the basement. Air conditioning and an automatic passenger elevator have made the building more comfortable. Offices and storage space have been squeezed out of every available corner to make room for the more than 280 employees who work there.

Outside, the building has changed little. It has not weathered and eroded nearly so much as Major Kingsbury feared. Storehouse A has become far busier and more useful than he ever dreamed.