3SS 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[December, 



announced their prncesses for making metallic casts of bodies by electricity. 

 Soon after, Mr. Mason devised an improved battery for the purpose. Mr. 

 Murray showed that non-metallic might be made to receive coatings of me- 

 tal, by covering them with black lead. Mr. Smee introduced a great im- 

 provement on the voltaic apparatus in use. Mr. Elkington discovered and 

 applied a new class of gold and silver salts to electro-plating. Lastly, Mr. 

 ■\Voolrich of Birmingham, substituted the magneto-electric machine for the 

 ■voltaic battery which had been employed by all his predecessors. Dr. Wil- 

 son stated that he had brought Mr. V.'oolrich's method before the Society, 

 because there was every reason to believe that it would supplant all the plans 

 at present in use in electro-metallurgy. 



The magneto-electric machine consists of a large compound horse shoe 

 magnet laid horizontally, in front of which a bar or keeper of soft iron, sur- 

 rounded by coils of covered copper wire, is made to rotate. — The electricity 

 is obtained from these wires, in virtue of the following law :— If a copper 

 wire be approached to a magnet, a momentary wave or «urrent flows in one 

 direction along the wire. If the wire be withdrawn from the magnet a se- 

 cond wave or brief current passes along it, hut in the opposite direction 

 from that which showed itself when it was approximated to the magnet. In 

 this way a series of alternating electric currents, in ojiposite directions, may 

 be obtained. On this principle the magneto-electrical machine is constructed. 

 The soft iron keeper which revolves in front of the horse shoe magnet be- 

 comes a temporary magnet whenever its rotations bring it in front of, and in 

 the same plane with the permanent one, and ceases to be one when it has 

 turned so as to be at right angles to the horse slioe. Every time the keeper 

 becomes a magnet an electric current flows along it in one direction, and on 

 each occasion of its ceasing to be one, a second current shows itself in the 

 opposite direction. These currents flow along the wires surrounding the 

 keeper. In the course of the revolutions of the latter, moreover, each ex- 

 tremity comes to be alternately opposite the north and the south poles of the 

 permanent magnet. This also occasions a reversal of the direction of the 

 electric currents. In consequence of these alternations, the magneto-electric 

 machine without some further equipment is useless for the purposes of the 

 electro-nietalhirgist, as the counter currents necessarily destroy each other, 

 and no permanent chemical decomposition can be effected by them. Mr. 

 Woolrich obviated this difficulty, by attaching to the magneto-electric ma- 

 chine a very simple and ingenious break, or contrivance, by which a uniform 

 current is obtained. This cannot be explained without a diagram. A draw- 

 ing of it will be found in Shaw's Electro. Metallurgy. Its eff'ect is to provide 

 a new circuit for each current, at the njoment that its direction changes, so 

 as to carry all the positive Electricity by one channel and the Negative by 

 another. 



Dr. Wilson " exhibited a Matjneto-Electric MaeJiine." fitted up with Mr. 

 Woolrich's break, and showed, by the uniform direction in which it moved 

 the needle of a galvanometer, that the originally alternating cnrrenls were 

 convened into a continuous one. Its application to Electro-Metallurgy was 

 further illustrated by employing the current from it, to plate with silver a 

 copper medal. 



It was further mentioned that Mr. Woolrich had successfully substituted 

 for the expensive Cyanide of Potassium, which was previously in use, a much 

 cheaper salt, the sulphate of potass, as solvents of the silver and gold em- 

 ployed in Electro-plating. Dr. AVilson concluded hy stating that tlie supe- 

 riority of the Magneto-Electro Machine, over the Voltaic Battery, as a source 

 of Klectricity, was great. The expense of maintaining the keeper in rota- 

 tion was the only outlay neciled to secure the efficacy of the instrument. So 

 that, though originally more expensive than the Voltaic Battery, it was, in 

 the end, much less costly. It is also much more cleanly, and quite under 

 control. By increasing or diminishing the magnetism of the keeper, which 

 can be effected by altering the distance at which the horse shoe magnet 

 stands froni it, and by other methods, as well as by varying the speed at 

 ■which the keeper revolves, the quantity and intensity of the Electricity can 

 he varied williin wide limits, accurately adjusted to suit the exigencies of the 

 Electro-Metallurgist. 



The Report of the Prize Committee, awarding the Prizes for Session 

 1844-45, was read ; and the Prizes were delivered by the President to the 

 successful candidates. 



Interesting Discovery at Hartlepool. Di'eiiam, — The site of an an- 

 ancient chapel at Hartlepool, dedicated to St. Helen, was recently discovered by Mr. J. 

 Yeal. It had long been supposed that the ruins of this chapel weie buried under a large 

 mound in the Farewell-field ; and in IS13 an attempt was made, but without success, by 

 Sir Cuthbert Sharp, to discover some remnant of the building. Mr. Yeal, however, 

 <1irected some workmen to remove theeanh near the centre of the mound, — beneath wh-ch 

 was discovered the base of a beautiful Gothic pillar. This having placed the mattet 

 beyond a doubt, he was directed by the corporation of the town to pnrsue his researches, 

 and exhume whatever portion might remain. The base of three other columns, t: portion 

 of the north and south walls, a part of the east end of the chapel, and a flagged pavement 

 at the west end, have already been brought to light. A considerable quantity of bt'autifully 

 carved stone, in a state of excellent preservation, and two mutilated images, have also 

 been dug out. From these it is evident, that this was at one time a Gothic building of 

 great architectural richness aod beauty. It is imiiossible as yet to ascertain the form and 

 dimensions of ihe chapel, but a few more days will probably throw light on the matter. 

 ThB building, of which only the ruins remain, is believed to have been erected by William 

 de Bias, who died in the 'eign of King John. Among the relics which have been since 

 turned up is a stone coffin— complete, with the exception of a piece broken off the lid, 

 which was a single large flat stone, shaped the same as the coffin ; inside of which were a 

 perfect skeleton, measuring fi\'e feet ten inches, that had evidently, from its position, never 

 been moved since its interment, and a consideiable number of very small human bones, 

 all lying tocether, in a separate place from those of fuU-grawu iDdividuuU, and which 

 cmed to have been the receptacle of infants only. 



ENGLISH HARBOURS OF REFUGE. 



At the sitting of Monday, Nov. 17, of the Royal Institute of France, 

 M. Mathieu in the chair. Baron Charles Dupin read the following 

 paper : — 



It is now 28 years since I laid before the Academy an account of great 

 works undertaken by the British Govtrument, ■with a view of making 

 Plymouth the finest port of defence and refuge for the royal Navy and 

 merchaut vessels. These works carried on with a remarkable activity, 

 altliougii begun oO years after those of Cherbourg, have long siuce been 

 coBipleted. 



At this present moment England is projecting the making of new ports 

 of agression, or. if you prefer it, of defence aud refuge, nearer and nearer 

 to the coast of France. Under more than one point of view these works 

 inteiest tha arts aud science; and such is the reason which leads me to 

 communicate them to the academy. 



In IS43 a select committee of the House of Commons, appointed to in- 

 quire into the accidents to trading vessels off the coast of England, in its 

 report recommended to the government the establishing of ports of refuge 

 in the British channel. The committee, acting most judiciously, abstained 

 from pointing out any particular situations for such ports; it, on the con- 

 trary, gave it as its opinion that the subject would be much better treated 

 by scientific persous having practical knowledge, and specially appointed 

 for the purpose. With a vievr of carrying out this recommendation. Sir 

 Robert I'ffl, the Prime minister, first ascertains that the persous the most 

 capable will undertake the inquiry just mentioned. 



Having taken this first step. Sir Robert Peel obtained from the Lords of 

 the Treasury the appointmwut of a commission, consisting of Sir Bjara 

 Martin, who was for many years chairman of the Navy Board, and who,, 

 during the war, had been a member of several important commissions of 

 inquiry as chairman ; Lieut.-Gene.ial Sir Huward Douglas, formerly 

 High Commissioner at the Ionian Islands, and previously Governor of the 

 IMilitary College at Sandhurst, author of several very valuable military 

 works ; Rear-Admiral Deans Dundas, an ofhcer of great experience ; Sir 

 William Symonds, Surveyor General of the Navy, and successor to the 

 celebrated Sir Robert Seppings; two naval captains, Juhn Washington, 

 and Fibber; Colquhoun, a colonel of artillery ; Alderson. a colonel of en- 

 gineers ; Sir H. Pelly, deputy-mastea of the Trinity House ; aud Mr. 

 Walker, President of the Institute of Civil Engineers of Great Britain, 

 aud worthy of such an honour from the importaut works of which he has 

 had the superinlendeuce. 



Here is the formal instruction given by (he Lords of the Treasury to 

 this grand commission as to Ihe objects to be forthwith more immediately 

 considered : — 



" First. To deterermine whether it be advisable to have a port of refuge 

 in the British channel, with a view to the public benefits which such a 

 work shall hold out; aud, on the other hand, what would be the cost of 

 executing the work* to he recommended. 



" Second. To determine the spot which will be best suited for a port of 

 thie description, so as to combine, in the highest degree, the three follow- 

 ing capacities : — 



" 1. That it may be entered with ease at any state of the tide by vessels 

 in danger from bad weather. 



"2. That Ihe port be such as to be suited to a naval station, in case of 

 war, and may at the same time serve for purposes of defence and attack. 



" 3. That it may offer ready means of defence in case of attack from an 

 enemy." 



This is not all ; should the commissioners not find that all these requi- 

 sites can be olitaiued by only one port of refuge in the British channel, 

 they are authorised to extend their surveys in consequence, and then to 

 report on the advantages peculiar to the differeut siluations they shall 

 deem advisable to reccommend, pointing out such as Ihey may cousider 

 the most eligible. 



These remarkable instructions ore dated the 2d of April, 1844. 



These commissioners lost no time in setting about the duties imposed 

 on them. The Euglish coast and ports on the British channel were sur- 

 veyed. The commissioners had the assistance of the informalion pos- 

 sessed by persous of special knowledge. They examined the most ex- 

 perienced pilots, the officers of the coast Guard, the most celebrated engi- 

 nears— such as Mr. Brunei, Mr. Rennie, Captains Samuel Brown and 

 Vetch; learned geologists— such as Mr. ISeche, President of the Board of 

 the Geological Map ; Mr. Philipps, President of the Society of Geological 

 Economy, Sec. 



As early as the 7th of August, 1S44, the commission had got through 

 its labours, aud presenti-d its report to the Lords of the Treasury. Fi- 

 nally, in consequence of an address to the Crown on this subject, the 

 First Lord of the Treasury laid on the table of the House of Commons 

 the commissioners' fiuul report. 



I shall, in a succinct analysis, lay before you the chief results of their 

 labours, looking at them with reference to hydrography and nautical 

 arts. 



At the first view it might be thought that the south-west coast of Eng- 

 land, liberally provided by nature, and during a long period seconded by 

 art, offers a suflicient number of ports of refuge, possessing all requisites. 



We have already mentioned Plymouth, to which must be added Fal- 

 mouth, tlie situation the farthest to the westward. Returning eastward, 

 vre successively find Dartmouth, Southampton, Portsmouth, and the 

 Thames. 



