Imagine this diminutive sculpture of Diana the Huntress as a rotating, 18-foot-tall, gilded weathervane atop the tower of the newly built Madison Square Garden. In collaboration with his friend, architect Stanford White (the Garden's architect), Saint-Gaudens originally designed the monumental Diana to reign over the New York skyline, a rival to Bartholdi's Liberty in New York Harbor. But Saint-Gaudens' figure proved too unwieldy to function properly (the original had metal drapery attached as a rudder) and was removed. He then designed a 13-foot version, which also failed as a weathervane and had to be bolted fast to the tower.
Saint-Gaudens went on to make Diana of the Tower in several versions and sizes. The National Gallery's three-foot bronze is a simplification of the original: he removed the flowing drapery and placed the huntress on a raised triangular base decorated with winged griffins.
With her slender limbs and graceful pose, Saint-Gaudens' Diana embodies an idealized feminine beauty. Her facial features, based on those of the sculptor's beloved model, Davida Clark, have taken on a classical perfection. Though engaged in vigorous physical pursuit, she remains elegantly composed, standing on tiptoe atop a globe, one leg extended gracefully behind her. Saint-Gaudens achieved a compositional balance, using the strong horizontals of her extended arm, raised elbow, and bow and arrow to counterbalance the figure's essential verticality.
Saint-Gaudens would have seen several mythological Dianas in Paris in the 1870s, but an elongated neo-mannerist bronze Diana by Houdon (cast 1741), which had a similar classical coiffure, had the greatest influence on Diana of the Tower. Unlike any of those prototypes, however, Saint-Gaudens' figure was conceived primarily as an eloquent and elegant silhouette, because a weathervane, seen against a bright sky, must be effective as a cutout shape.
More information on this object can be found in the Gallery publication European Sculpture of the Nineteenth Century, which is available as a free PDF https://www.nga.gov/content/dam/ngaweb/research/publications/pdfs/european-sculpture-19th-century.pdf