More than a century separates the opening dates of the most recent and the oldest public-library buildings in the Quad Cities. The differences between these buildings reflect our changing relationship to the environment, and their architecture reflects the evolution of the library from a symbol of culture to a community center.

Davenport's Eastern Avenue branch library (at 6000 Eastern Avenue) opened a year ago on July 10. The horizontal shape of the building and curved entrance relate to its surrounding environment, an open, grassy area of gentle rolling hills. The library has been designated by the U.S. Green Building Council as a Leadership in Energy & Environmental Design (LEED) building. Its environmental features include a geothermal-heating and -cooling system, stormwater-management systems for the roof and parking areas, and energy-efficient lighting. Even the building materials were selected to ensure a healthy environment for the library staff and patrons.

A 22-foot-high, brightly painted yellow-orange aluminum sculpture was installed at 100 17th Street in Rock Island in 1982. Placed near the entrance of the First National Bank of the Quad Cities, it was created to invite the viewer to join the celebration of the bank's 130th anniversary. The sculpture was titled, appropriately, Invitation.

Though the building is now the Modern Woodmen Bank building, Invitation stands in the same location. Its intense and pure color suggests a brightly colored flower, and the sculpture seems to bloom from its relatively small, rectangular base - almost like a rapidly growing plant in a vase that has become too small.

The uniform color, on the other hand, suggests industrial fluorescent yellow. Though the sculpture's shapes are fluid, even elegant, they are formed from hard-edged, seamless sheets of metal. The sculpture's dynamic arcs seem to describe enormous paths of flight - more akin to a jet fighter than a bird.

Passages is a grouping of four rectangular columns prominently placed between the Family Museum and the Bettendorf Public Library on Learning Campus Drive. The column closest to the library lies flat on the ground. In sequence, the other three stand angled at 45 degrees, 67 degrees, and finally fully vertical. The effect of these 18-foot-tall, stainless-steel columns rising in a stop-motion progression is impressive.

Yet what ultimately catches one's attention is the brightly painted sphere perched precariously at the top of the standing column. An area the size of the sphere has been scooped out of the other columns. These smooth inverse curves are painted in the same bright colors as the sphere - yellow, red, and green - and visually soften the angular metal impact of the sculptural group. They feel like a finger's indent in a stick of butter. The positioning of these indents creates an illusion of an upward trajectory or path that the sphere has taken.

(Editor's note: This is the first in an occasional series on the history of public art in the Quad Cities.)

Standing on a ridge overlooking the Rock River, an 18-ton granite statue of Black Hawk dominates the space before the Watch Tower Lodge at the Black Hawk State Historic Site (1510 46th Avenue in Rock Island). This is near the location of the Native American village Saukenuk, the largest settlement in Illinois when it became a state in 1818. The statue's commanding presence tells us that this was a man of great importance.