to obtain a discontinuance of the new conductors in Her Majesty's ships. This gentleman in a letter to their Lordships, dated 6th May, 1839, says "If a ship provided with Harris's Conductors should unfortunately be struck by lightning, the electric fluid will descend into the hull, there create a lateral explosion, and perhaps in one moment hurry into eternity every soul on board the ill-fated vessel:" an awful prediction certainly; very cunningly devised, and very well calculated to alarm at the instant, the great responsibility of the Board of Admiralty, by a direct appeal to fears and prejudices rather than to sober judgment, and with a view to obtain the dismissal of the new conductors from the public service, and make way for a well known form of conductor of copper wire, proposed by Mr. Roberts in the same letter.* The evidence above quoted was most important in removing scare-crow arguments of this kind from the public mind, mere rags of science quite unworthy of all philosophical inquiry. Such statements at the present moment are set completely at rest by the well known fact, that since the new system of conductors has become general in the public service, damage by lightning has positively vanished from the records of the navy. In no instance has any damage arisen to Her Majesty's ships fitted with these conductors; they have been struck by heavy discharges of lightning with impunity in all parts of the world. In short the only damage by lightning which has been recently experienced has arisen in a few solitary vessels in which the conductors had not been placed. The various questions (2) to which we have already adverted, viz: attraction of conductors for the matter of lightning; lateral explosion; danger of sending conductors through the ship, &c., were also fully investigated by the commission upon the principles of a sound inductive philosophy, and completely set at rest. The author's views (6) were considered as satisfactorily established by very numerous and striking facts: with respect to the assumed "lateral explosion," the commissioners do not hesitate to state their "entire conviction of the futility of the objection."† 23. An objection of a mechanical kind was very strongly insisted on at this time, and which doubtless influenced the Board of Admiralty in their determination to discontinue the conductors in the navy. It was said that the grooves cut in the masts for the reception of the series of plates would necessarily weaken and damage the spars. No amount of reasoning or evidence appeared sufficient to counterbalance this assumption. Nevertheless, the reasoning and evidence was perfectly conclusive on the point, and experiment clearly showed that the spars were actually strengthened by the application of the copper-plates. It may not be uninteresting to notice here a series of experiments carried out at the Portsmouth Dock-yard relative to this point in 1831, and detailed in the Report of the Commissioners, page 81. A light flexible spar of about thirty-four feet in length, the flying Jib-boom of a twenty-eight gun sloop then fitting with the conductors, was supported at each end on two fixed points, and weights applied at its centre so as to subject the spar to flexure. The amount of flexure * Report, page 45. NO 6.-VOL. XXI. † Report, p. 8. 2 Q was measured to the 100th of an inch, by a fine silk line attached to the centre of the spar, and passing over a pulley an inch in circumference; the axis of the pulley carried an index in front of a circular scale divided into 100 parts, much in the way of a common wheel barometer. Things being thus arranged, the amount of flexure with certain weights was noted upon eight positions or squares of the spar previously to the copperplates being applied; and again, subsequently to being applied: the result was, that the spar sustained a greater weight with the same amount of flexure in every position. In certain positions its resistance to flexure was increased by nearly one sixth. An account of these experiments, which are well worth attention, from many circumstances not requisite to notice here, will be also found with illustrative cuts in the volume of the Nautical Magazine for 1834. Reports from officers in the command of the ships fitted with the conductors, very fully confirmed the results of these experiments: Commander Turner, of H.M.S. Dryad, on the coast of Africa, stated in reference to the conductors-"carrying sail has no effect on them, we carry a heavy press of sail sometimes." Captain Fitzroy, of the Beagle, says in his report-"were I allowed to choose between masts so fitted and the contrary, I should decide in favour of those with Harris' conductors, even in such small spars as the Beagle's royal masts; the plates of copper held their places firmly, and increased rather than diminished their strength."* Similar statements were made by several other officers, viz.-Captain F. Grey, Captain Wellesley, Commodore Pell, and others. No amount of philosophical evidence, however, had any weight. The objection was strongly insisted on, although it had no other support than that of an inferior shipwright officer of the Plymouth Dock-yard, who, finding some rents in the condemned top-gallant-masts of the Caledonia, 120, from which the copper-plates had been removed, and which had been left exposed to a hot sun on the mast-slip, gave it as his opinion (in a letter to the surveyor of the navy), that these rents had been caused by the application of the conductors. This most unsatisfactory and suspicious statement, was speedily converted into a conclusion that the spars of this ship had "been injured by them (the conductors), and condemned in consequence." The whole of this, however, was subsequently disproved;† still, the exception was insisted on by those opposed to the system, and who being in power could always discountenance the practical progress of any invention in the Royal Dock-yards. Every one who has to struggle with official influence and prejudice, must expect to encounter difficulties of this kind, and must not be discouraged by them, but trust to the truth coming eventually to the surface, which it is sure to do at last, provided the case be based on sound principles supported by facts. The crooked policy of subordinate officers in the public service, and which sometimes leads them to compromise See report to the House of Commons-"Harris's Lightning Conductors," printed February, 1840, pages 10, 48 and 39. †See report already alluded to, pages 9, 10, and 19. facts, with a view to a party purpose,-very seldom leads to any satisfactory result. 24. It appeared by the evidence given in the report, page 26, that the surveyor and assistant surveyor of the navy, were both decidedly adverse to the employment of the new conductors in H.M. ships. Sir W. Symonds grounded his objections on the want of proof of their efficacy; on the danger of bringing lightning into the ship; on the cost; and on the damage which would be done to all the masts of the navy; and last, not least, to the inconvenience which would arise from the removal of the conductors in case of "a panic arising from a failure of the plan;" certainly, strong and powerful objections, more especially as coming from such an influential quarter. Nothing but the most powerful evidence from facts, and the judgment of a perfectly independent and fully qualified tribunal, could have enabled the inventor to maintain his ground. Sir W. Symonds further objected to the fixing of conductors in ships, and preferred a temporary chain; but recommended more especially a plan of the assistant surveyor, which consisted of part of the plan of copper-plates then before the commission, conjoined with the method of wire ropes, which he contended would be preferable to all other plans and save expense. The Commissioners carefully investigated this method, as also certain other forms of temporary conductors as recommended by Mr. Roberts, after the plan employed in the French navy. But, they came to the conclusion, that all the methods of conductors of this kind, can only be regarded as a temporary and inadequate expedientthat such conductors "are liable to all the casualties to which a ship's rigging is exposed, and liable to lead to serious accidents." 25. Having examined the question of expense, and shown how the cost of the system might be reduced, the Commissioners conclude their report in the following unqualified and strong terms:-" considering the number of lives lost by lightning, the immense amount of property which has been destroyed, and which is still exposed without adequate protection, the inconvenience which has arisen, and is still liable to arise from the loss of services of ships at moments of great critical importance; the difficulty of procuring new spars on Foreign stations in time of war, not to mention the great expense of wages and victuals of the crews of ships rendered useless until repaired, we again beg to state our unanimous opinion of the great advantages possessed by Mr. Harris's conductors above every other plan, affording permanent security at all times and under all circumstances against the injurious effect of lightning; effecting this protection without any nautical inconvenience, or any scientific objection whatever, and we therefore most earnestly recommend their general adoption into the Royal Navy." 26. This investigation and report to the House of Commons complete and strong as it was, and emanating as it did from the highest Naval and Scientific authorities, actually selected by the Board of Admiralty itself, did nevertheless, fail to ensure the employment of the conductors in the Royal Navy.-The Earl of Minto, then the First Lord of the * Report pages 6 and 11. Admiralty did not feel himself at liberty, to follow out the "earnest," recommendation of the commission, but determined on further trials of temporary conductors of wire ropes, which the Commissioners had rejected as "dangerous and inexpedient." Up to February, 1841, the conductors had been replaced in five ships only, one of them under the Dock-yard government of Sir Charles Adam, the first Naval Lord, with a view of contrasting the cost of the new conductors with the expense of conductors of wire ropes: the Acteon, also had been refitted in 1838, in order to meet the debate in Parliament on Lord Eliot's motion and furnish some ground for saying that the plan had not been laid aside. In all these instances, the inventor was denied any interference in the work, which was placed at the mercy of those inveterately opposed to the further employment of his plan in the navy-the cost of fitting was run up to an enormous amount. In the meantime, orders were issued for the trial of certain forms of conductors of wire rope, and at last an order was issued, dated 27th August, 1841, the immediate effect of which was to throw overboard, the report of the naval and scientific commission altogether. It provided that "all ships ordered to be brought forward are to be fitted with wire rope lightning conductors, unless others be applied for, when the request is to be referred to their Lordships." Of course no officer appointed to a ship would care to make such an application in opposition to the views and policy of the Surveyor's department of the navy, countenanced by the first Lord of the Admiralty. Moreover, when the question of compensation arose for the many years of anxious labour and expense to which the author had been subject in bringing forward his plan, and the great benefits likely to arise from it to the navy and the country as stated by the Commissioners, he was informed officially, that the Board of Admiralty, although, admitting that he had the merit of calling public attention to the subject, yet did not see sufficient reason for granting the compensation sought. subsequent communication, dated 22nd February, 1841, the plan was allowed to be "an ingenious and successful application of well known principles, but not entitled to any award, as for an original invention, adopted into the public service;" as if every mechanical contrivance was not an application of well known principles. Take for example, the diagonal trussing for ships; is it not seen on every farmer's gate in the country? yet for this as applied to ships, a large sum of money was awarded. Thus was the system of permanently fixed lightning conductors for Her Majesty's Navy, now every where admitted as of the highest importance to the country, doomed for the time to succumb to authority in favour of inferior and objectionable means of defending the navy from lightning, and the inventor denied all right to public consideration. And this was done in opposition to the views of the greatest scientific authorities in Europe, and directly in the teeth of a naval and scientific commission, expressly selected by the Board of Admiralty itself, to investigate and report on the merits of the question. (To be continued.) *Return to the House of Commons, 17th March, 1841. In a DISTANCE BY SOUND. SIR. As the determination of distances by sound is a very useful (and under proper precautions) correct mode of obtaining a base for surveying or military purposes, when actual measurement cannot be obtained, the following description of the method used during the late survey of the north-west Coast of America may be useful to your nautical readers. It is an ascertained fact that sound travels at the rate of 1090 feet in a second of time, when the air is at the freezing point, or 32° of Farenheit, and that this rate is accelerated by 1.19 feet for every degree above that point. If therefore the correct interval between the flash and report of a gun can be measured, the distance is easily deduced. The object then is to measure this interval to the nearest fraction of a second, to arrive at which the following plan was found to answer remarkably well. First ascertain by repeated experiments the number of beats or ticks of your watch, to a second of time. Pocket chronometers generally beat five times to two seconds. Fit your hat or cap with a watch pocket to hang over your ear, so as to leave your hands free to hold the glass. Now for the modus operandi. Herald and Pandora being moored about five miles apart, and the exact distance being required, Herald hoists "Preparative." The long brass nine-pounder on the forecastle is run out on the side nearest Pandora, and pointed towards her, loaded with full service charge and slightly elevated. Pandora's officers are by this time assembled with their glasses in their hands, and their watches at their ears, perfect silence enjoined, and the answering pendant at the mast-head. This is acknowledged by Herald's dipping "Preparative," and as soon as Pandora's answering pendant is dipped in return, slowly hoisting a large red ensign (or any other flag easily seen) at the main; the moment it is up her gunner fires. The observers in Pandora having their glasses fixed on Herald, and mentally counting, one, two, one, two, one, two, with the beats of their watches, are ready to commence counting from the instant the flash is seen, till the sound reaches them. It will be found that when counting, it is more convenient to mark each ten beats by putting a finger down either on the glass or gunwale, as it is not easy even to think long numbers in rapid succession, and the number of tens is easily marked by the fingers down. Suppose this operation has been repeated three times in succession, by each vessel; we have now the interval in time which must be reduced to space. I should observe that the thermometer must be correctly noted each time. Example. Wed. 19th Jan., '48 For base by sound between Herald's 4th, and Pandora's 3rd position. Interval measured by Lieut. Wood's watch, which beats 240 to a minute. Thermometer 81°, wind light and across the line of sound. |