E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Diamond (Newtons favourite little dog).
One winters morning, while attending early service in Trinity College, Newton inadvertently left Diamond shut up in his room. On returning from chapel he found that the little fellow had upset a candle on his desk, by which several papers containing minutes of many years experiments, were destroyed. On perceiving this irreparable loss, he exclaimed, Oh, Diamond, Diamond, thou little knowest the mischief thou hast done! (Diffusion of Useful Knowledge: Life of Newton, p. 25, col. 2.)
Huygens, 1694, referring to this accident says: Newtonum incidisse in phrenitin abhinc anno ac sex mensibus. An ex nimia studii assiduitate, an dolore infortunii, quod in incendio laboratorium chemicum et scripta quædam amiserat.