Yaneff.com

"In August of 1859 James McNeill Whistler lived close to the London Docks and that busy area of the Thames called 'The Pool'. During the following two months he created eight etchings (including Billingsgate) upon this subject. Each of these path-finding etchings explore then uncharted waters. The docks, barges, ships, workers and adjacent buildings were brilliantly analyzed by Whistler in patterns of both horizontal and vertical lines and spaces.
London Docks, photo ca. 1890

In Billingsgate the vertical presence of the foreground barge and the standing figures directs our eyes to the tall buildings and masted ships in the background. These very vertical elements are countered by the bridge in the background.

Beginning with etchings such as Billingsgate, Whistler was the first artist to recognize that the eye and brain cannot focus upon near and distant objects at the same time. In his etched art, this realization led to a complete re-examination between line and form and light and shade. The path that began with these 1859 Thames etchings culminated in Whistler's Venice etchings of the early 1880's, etchings which many scholars now term of the first works of truly modern art."

Whistler is one of the truly great painters of the nineteenth century. Yet it is in his oeuvre of original etchings and lithographs that his true genius becomes most apparent and his influence upon the development of twentieth century art is at its most far reaching. Whistler turned first to etching and his initial great works in this medium date from the mid 1850's when he lived in Paris and met such artists as Degas, Legros and Courbet." (theartoftheprint.com)

"James Abbot McNeil Whistler was an American-born, British-based painter and etcher. Averse to sentimentality in painting, he was a leading proponent of the credo, "art for art sake," a rejection of the accustomed role of art, which, since the Counter- Reformation of the 16th century, had been put in the service of the state or official religion, and later of Victorian-era moralism. It opened the way for artistic freedom of expression in the Impressionist movement and modern art. The slogan continued to be raised in defiance of those, including John Ruskin and the more recent Communist advocates of Socialist realism who thought that the value of art lay in serving some moral or didactic purpose. The concept of “art for art’s sake” continues to be important in contemporary discussions of censorship, and of the nature and significance of art.

Whistler took to signing his paintings with a stylized butterfly, possessing a long stinger for a tail. The symbol was apt, for Whistler's art was characterized by a subtle delicacy, in contrast to his combative public persona." (newworldencyclopedia.org)