William Stanley Haseltine was a 19th century American painter who studied in the US and Europe.
Originally from Philadelphia, where he studied at the University of Pennsylvania and exhibited early in his career at the Pennsylvania Academy of the Fine Arts, he moved to New York, for a time working out of a building that also housed studios for Frederic Edwin Church and Albert Bierstadt.
Haseltine produced studio works from his sketches and watercolors painted on location in Europe, and eventually transitioned to American subjects, particularly of the New England coast.
After the death of his wife, he remarried and moved to Europe, where he would spend his later career based in Rome, but traveling extensively and painting a variety of European subjects.
I particularly like his watercolor and gouache studies — in their more finished form filled with light — and in their more abbreviated form taking on the charming quality of part drawing/part painting — often on toned paper.