This particular Funny Portrait Story (of which the Amateur Historian now recollects there are several) is also an installment of Funny Things that Happened to Pitt the Younger.
The landscapist Sir Francis Bourgeois once told the diariest Joseph Farington that, he, Sir Francis, had once
"Called on [Gainsborough] and saw a half-length portrait, and was struck with the haughty expression of the countenance, and observed it to Gainsborough, who expressed satisfaction at the remark, as it proved that He had hit the Character. Gainsborough said that it was a portrait of Mr. Pitt, who He said came the day before to sit for his picture and on coming into the painting room sat down in the painter’s chair and began to read.
Gainsborough, struck with the hauteur and disrespectful manner of Mr. Pitt treated him in this way.- He took up his pallet and seeming to be trifling among his Colors, began carelessly to hum toll, roll de roll, on hearing which Mr. Pitt recollected himself shut his book, and sat in a proper manner."