Inconsistent, archaic spelling, hyphenation, typography etc. have been retained, also in proper and geographic names and in numbering of illustrations and plates, except as listed under Changes below. Depending on the hard- and software used and their settings not all elements may display as intended, and zooming and horizontal and/or vertical scrolling may be necessary to view the larger elements.
The book regularly refers to a book published by the author’s father: An Account of the Bell Rock Light-House by Robert Stevenson, which is available at Project Gutenberg: https://www.gutenberg.org/ebooks/48414.
Text in a dashed box underneath an illustration is text that does not occur as such in the source document, but that has been transcribed from inside the illustration for the sake of clarity.
Page xi: the errata have already been corrected in the text; see also under Changes made below.
Page 149, ... the same mass of Mull stone would weigh 4252 tons ...: possibly an error for 4152 tons (which would make the calculation correct).
Page 174: ... somewhat on the same plan as that which is described in the Appendix ...: it is not clear to which Appendix this refers; possibly the reference is to Plate XXXI.
Page 252 ff.: Figures 59 and 60 are identical.
Page 271 ff.: Figures 71 and 72 are identical.
Page 276, See fig. 73 and the following paragraph: the description appears to refer to Fig. 71/72 rather than to fig. 73.
Page 362, Conversely, n′ is the origin of the co-ordinates for the grinding centre O of the interior convex refracting surface BC, ...: in the illustration (Fig. 110) this appears to be a lower case o.