THE LIGHTHOUSE WORK OF SIR JAMES CHANCE.*
CAMPBELL, addressing the "Mariners of England," should have concluded his poem with a stanza reminding our Admiralty, and Harbour Boards that, although "Britannia needs no bulwarks," her coasts ought to be guarded by light-
houses furnished with the best illuminating apparatus that money could provide. We were far from that degree of perfection half a century ago, when the beams thrown from
the phares of Cape Grisnez and Cherbourg were of greater range and brightness than the reflections from the Lizard, the
Forelands, and Flamborough Head. In this branch of applied science France kept the lead, from Buffon and Condorcet downwards to Argand, Arago, and the inventor of the modern lighthouse system, Auguste Fresnel. Between 1831 and 1851 two English firms, one of Arhich was " coached " by Fresnel's brother, tried to produce the new dioptric apparatus, but, after some experimental work, gave up the attempt. Their diffi- culties were by no means lubricated by the Excise restrictions of the day, which prohibited the manufacture of the lenses in question unless a permissive Order in Council had been previously obtained, and levied a duty of 300 per cent. on the value of the glasses, no rebate being allowed on the large quantities of the article which were defective and unsaleable. In 1850 Messrs. Chance, of Spon Lane, Birming- ham, who were likewise "coached" by a French expert, made a new start in the matter, with the result that the specimens of their output shown in the Paris Exhibition of 1855 were pronounced by specialists to be equal to the best French lights in illuminating power, completeness of mounting, and accessory arrangements. Another four years passed before our Government aroused itself to the necessities of the situation. At length in 1859 a Royal Commission was appointed to inquire into the lights, buoys, and beacons of the United Kingdom. That body was not long in recognising the defects of our system, which reached their maximum of inefficiency on the coasts of England proper. The elaborate investigations of the Commission fully justified its appoint- ment. To say nothing of the inferiority of our burners, there was a great waste of the reflected light, which was often thrown in wrong directions :-
' In some cases the fault appeared to arise from want of con- sideration of the wants of the locality ; in others from want of adjustment in apparatus ordered with insufficient specifications by the authority giving the order, originally constructed by a manufacturer without reference to elevation, and finally placed by the authorities, without considering the construction, at an eleva- tion for which it was not fitted.' There were also cases of faulty manufacture, of bad glass, and of inaccurate grinding. They [the Commission] found first that the dip of the sea horizon below the geometrical horizon had never, in the United Kingdom, been properly taken into account in dioptric lights ; secondly that the various parts of the dioptric apparatus had not even been 'adjusted to the flame and the geometrical horizon with sufficient 'accuracy."
This excellent book records in detail how much the Com- mission was guided, from first to last, by the advisory help of Sir James (then Mr.) Chance, who was largely associated in its labours, and was, in fact, the prime mover in the work of wholesale reconstruction and readjustment that ensued. The tale points its moral, to appreciate which we should not forget that the glass materials must be colourless and free from flaws, the lenses and prisms cast, ground, and
polished with extreme care, the parts of the illuminating -apparatus fitted together with minute exactness, to say
nothing of the auxiliary burners, or of the adaptation of the whole to the particular lighthouse concerned. If these technicalities may be more or less mastered in the usual rough-and-ready, empirical English way, it is not so with the equally necessary calculations of the curvature of a prism, the reflecting angle of a eatadioptric mirror, the parallelisa- tion of rays of light, and other questions pertaining to high
mathematics. Why was Chance the first Englishman who could do all this P Because, apart from his extra brain-
power, such was his training and knowledge that he had
• The Lighthouse Work of Sir James Chance, Bart. By James Frederick Chance, M.A. With a Preface by James %onward, C.E., F.S.A. London: Smith, Elder, and Co. [5s. net.]
taken high honours in mathematics and science at the London University, and afterwards graduated at Cambridge as Seventh Wrangler. Thus when the lighthouse topic came to the front he was able to deal on equal terms with experts like the Astronomer-Royal, Faraday, and Professor Tyndall, who were glad to come to Birmingham for his advice. Again— blackest of swans for an English glass-blower--Sir James Chance was a fair classical scholar, had studied Hebrew, knew modern languages, and had acquired a certain knowledge of law. Here was the secret of the notable lucidity of observation, criticism, and explanation which marks his letters and technical papers as printed in this volume. His humanity wentbeyond the work of saving the lives of so many of those who go down to the sea in ships : he was a general educational benefactor at home. Birmingham will not forget his splendid gifts to the city, which included an endowed public park, the founda- tion of the " Chance School of Engineering" at the University, and of some private schools near his factory. We should explain that the lighthouse work in question did not altogether divert Sir James Chance's attention from the general business of his firm; also that from 1856 to 1871 the Spon Lane lighthouse branch, as personally directed by him, supplied three hundred lights to the United Kingdom and various parts of the world. The volume is by Sir James's second son, who succeeded him at the glassworks. It will interest ordinary readers as well as the experts, who will enjoy its scientific details and figures.
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