Theatre Design & Technology - Fall 2006 - 18

While the two outer wheels of the control unit do not transmit
power, inspection reveals that the slightly larger middle one
does. To raise the floor the crossed belt must be moved to the
center position using the guide handle. To lower the floor,
moving the uncrossed belt to the center position creates the
necessary downward direction. Through a series of gears, energy is transferred to a continuous shaft running the width of
the auditorium. This line shaft consequently powers a total of
seven major flathead gears (fig. 3), each with a lengthy
threaded shaft extending downwards. A nut or "floating
collar" moves up and down the shaft according to the direction of the rotating movement, which, in turn, is attached to connecting rods that are secured to a
corresponding floor girder below. These seven pairs of
connecting rods normally are hidden from view by an equal
number of column facades located at the rear of the auditorium; one of which is shown uncovered in figure 4. The primary floor girders remain single solitary timbers
(approximately eight by fourteen inches) and run the entire forty-plus foot length of the auditorium floor. Figure 5
shows detail of a girder braced for added support while the
floor is in the inclined position. A fixed subfloor
structure, designed by Adams to support the
girders when lowered to a level position, now is
reinforced to meet current building codes.
Although oral tradition held it took several

Of very special interest was the unique
moving floor system which, in itself,
cost a total of $1,100. For comparison
purposes, a contract of $1,316 covered
the plumbing and gas piping
throughout the entire building.

COURTESY DOVER, NH, PUBLIC LIBRARY

accounts of employing such mechanical means is unusual
and, when successful, hardly on the scale of design and usage
envisioned by Adams. For example, Neche Hall (1900) in
Neche, North Dakota-lost to interested historians now for
over twenty years-had its floor balanced in the middle, allowing the removal of stops and the shifting of the floor like a
teeter-totter from a level position to a raked one. This venue
utilized a floor thirty-five by fifty feet capable of tilting one end
two feet (thus a total rake of four feet) through the most basic
of playground maneuvers (Zivanovic 1988). Such mechanics
compare poorly to the Rochester system.
To date, the closest comparable system located is found
in the St. George Social Hall (c. 1875-1880) in St. George,
Utah. As described by local historian Bart Anderson, the portion of the floor that moved in this venue (later known as the
Opera House) was thirty by fifty feet, which once again makes
it similar in size to the Rochester floor. The movement of the
floor was powered, however, by four large wooden screws
turned manually from below. According to Anderson, the mechanical system was rotated using wooden pegs like a capstan
employed to move an anchor on a boat (Anderson 2005).
While similar in some very basic
characteristics to that which is found
in Rochester, this floor today remains stationary and no longer
moves as designed. Consequently,
the title of last historic moveable theatre or hall floor in use in the United
States falls, I argue, to one present
in southeastern New Hampshire.
(Some modern moving floors exist,
of course. One such floor system is
in the Municipal Auditorium in San
Antonio, Texas, which was designed,
manufactured, and installed in the
mid-1980s by the Peter Albrecht
Company of Milwaukee, Wisconsin.)

Figure 7. George G. Adams, circa 1891.

THE ROCHESTER FLOOR SYSTEM
The moving portion of the Rochester auditorium floor is
roughly fifty-seven feet in width and forty-one feet in length
(currently seating nearly 360 patrons), being raised and lowered at its rear edge approximately three feet. The key mechanics of the system are accessed only through a small floor
opening and is located in a cramped crawl space in the left
rear of the auditorium (essentially between the balcony floor
and the ceiling of a small lobby area and office space). Here
can be found the three-horse-power electric motor, belts, and
gears that enable the rising and lowering of the floor. The
power generated by the electric motor is connected through a
series of leather belts (fig. 1) to a three-part control unit (fig.
2). Although initially this control unit appears an entanglement of belts, it proves to be simple in overall technique.

hours to complete the raising or leveling of the floor, in actuality it takes closer to three-quarters of an hour as the floor
moves approximately one inch per minute. Figure 8 captures
Anthony Ejarque of the Opera House staff throwing the electrical control switch to the "Start" position, thus placing the motor in low gear. If the various drive belts remain in place as
needed and all seems to be running smoothly, the electrical
control switch is moved to the "Run" position and the motor
supplies all the necessary power for shifting the floor, plus a
slight vibration to the control area and a rhythmic hum to the
event. The wooden handle of the control unit then can be used
to guide the desired belt into the center position, if not already
preset. Once fully engaged, the unmistakable sounds of the
slap of the rapidly turning leather belts, whirling flywheels, and
the clicking teeth of gears fills the auditorium. Because one viTHEATRE
F

2006

DESIGN

TECHNOLOGY

Table of Contents for the Digital Edition of Theatre Design & Technology - Fall 2006