From Charles Goodrich, Lives of the Signers of the Declaration of Independence (1829): "He possessed a library, which contained the most distinguished literary productions of the times; and in his library room was to be found a collection of scientific apparatus, with which he amused himself in his leisure hours, and added greatly to his stock of knowledge, The following anecdote furnishes evidence of the estimation in which he was held, as a philosopher, and a man of letters. Sometime during the revolutionary war, Bordentown, the place where Mr. Hopkinson and family resided, was suddenly invaded by a party of Hessians. The family had hardly time, to escape before the invaders began the plunder of the house. After the evacuation of Philadelphia, by the British, a volume, which had been taken from the library of Mr. Hopkinson, at the above period, fell into his hands. On a blank leaf, the officer, who took the book, had written in German an acknowledgment of the theft, declaring that although be believed Mr. Hopkinson to be an obstinate rebel, the books, and philosophical apparatus of his library were sufficient evidence, that he was a learned man."