Sargent made hundreds of rapidly drawn charcoal sketches of society personalities, drawings he referred to as "mugs". He made these in response to a high demand for his work, and not being able to satisfy all with oil paintings, kept his sitters happy with quick charcoal drawings. (http://poulwebb.blogspot.nl/2014/04/john-singer-sargent-part-20.html)
JOHN SINGER SARGENT'S paintings read like novels.... Sargent is the most literary of painters, although that aspect of his work has rarely been discussed. In fact, his art parallels that of Henry James, that most painterly of writers, a close friend and sometimes neighbor and who often praised Sargent in his critical work.