[1] Tregellas was, from youth, fond of drawing, and won prizes as an artist at the Royal Cornwall Polytechnic Society, Falmouth, from 1846 to 1848.
He married at Holy Trinity Church, Brompton, on 2 November 1861, Zoe, third daughter of Charles Lucas (1808–1869).
[1] Tregellas was the author of an anonymous volume on China, the Country, History, and People, published by the Religious Tract Society (1867).
His Historical Sketch of the Defences of Malta was printed for the Royal Engineers’ Institute at Chatham in 1879, and Historical Sketch of the Coast Defences of England appeared in the Royal Engineer Institute Occasional Papers (vol.
The lives of many eminent Cornishmen were written by Tregellas in the first thirteen volumes of the Dictionary of National Biography.