PLATE III.
BELL ROCK LIGHTHOUSE.
That period has at length arrived, and the Trinity House, under the advice of Mr. Douglass, their Engineer, have resolved that Smeaton’s Eddystone—the engineer’s long cherished object of veneration—must be renewed, and henceforth Stevenson’s Bell Rock must be held as the earliest existing type of a class of bold and skilful works—still few in number—which, by converting a dark sunken danger into a source of light and safety, have saved many a ship, and cheered the heart of many a tempest-tossed sailor, as happily expressed in Sir Walter Scott’s impromptu “Pharos loquitur,” written in the Album of the Lighthouse, when he landed with a deputation of the Commissioners in 1814.
“Far in the bosom of the deep
O’er these wild shelves my watch I keep,
A ruddy gem of changeful light,
Bound on the dusky brow of night;
The seaman bids my lustre hail,
And scorns to strike his timorous sail.”
CHAPTER III.
LIGHTHOUSE ILLUMINATION.
1801–1843.
Early modes of illumination—Facet reflectors and lamps—Silvered copper reflectors and Argand lamps—Isle of May coal light—Improvements in catoptric lights—Distinctions for lighthouses invented by Mr. Stevenson, viz., flashing, intermittent, and double lights—Floating light lantern—Lighting of stage of Covent Garden Theatre—Dioptric system of lighthouse illumination.
Seeing that, for reasons stated in the last chapter, I was led to give up the idea of attempting to follow any chronological sequence in this Memoir, it may perhaps be convenient, before speaking of my father’s general practice as a Civil Engineer, that I should supplement the sketch I have given of the Bell Rock Lighthouse by some account of the other important duties he performed as Engineer to the Commissioners of Northern Lighthouses—an office which, as we have seen, he held for so long a period.
The lighthouse towers of the last century, though useful as beacons by day, were after all most imperfect guides by night. Indeed, the rude expedients adopted at that early period to give light to the sailor in a dark and moonless sky, present a very curious contrast to the modern system of lighthouse illumination—the result of careful study by modern philosophers and engineers. If proof of this be wanted, we have only to refer to the twenty-four miserable candles, unaided by reflectors or any other optical contrivance, which shed their dim and uncertain light from Smeaton’s famous Eddystone for nearly half a century after it was built.