Improvements in dioptric apparatus for lighthouses /
Douglass, William Tregarthen.
Purves, John Archibald.
Tudsbery, J. H. T.(John Henry Tudsbery),1859-1939,ed.
London : Published by the Institution, Great George Street, Westminster, S.W.,
1899.
By permission of the Council. Excerpt minutes of Proceedings of the Institution of Civil Engineers Vol. cxxxvii. Session 1898-99. Part iii.
Lighthouses
England London.