2SS 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[AuffirsT, 



1i(le-\\ay, is no oiisy task, as Colonel Pasloy afterwards found on un- 

 dertakiiia; this operation. When he first received the order to atteni|]t 

 to demolish the brig William, in the Thames, he was of opinion that 

 volLiie electrieity would afford the best means of effecting that object; 

 but at that lime he was not provided with a proper battery, and though 

 Jie might have procured one in time, yet lie jneferred inferior methods, 

 whieli lie and his corps thoroughly understood, to an untried though 

 more promising method, which lie did not tliink that they would be 

 able to reduce to any certainty, without a vast number of experiments 

 and a considerable loss of time ; because those distinguished chemists 

 and electricians, both in this and in other countries, who have recently 

 brought the important science of electro-magnetism to such perfection, 

 liaving nothing to draw their attention particularly either to subter- 

 laneous or subaqueous explosions, had never investigated the best 

 mode of applying the voltaic battery to large explosions, under ditficult 

 circumstances. As soon, therefore, as Colonel Fasley, by application 

 to tlie Master-General and Board of Ordnance, had received a voltaic 

 battery of ten large cylinders, &c., made by Mr. Newman, of Regent- 

 streeti on Professor Daniell's improved ))rinci]ile, he commenced a 

 series of experiments for reducing the application of voltaic electricity 

 to the jnirposes of military mining, as well as of great subaqueous ex- 

 plosions, to a system, in which he was assisted by Captain Sandham 

 and Mr. Howe, under whom Serjeant-Major Jones, and as many non- 

 commissioned officers and juivates as were found necessary, were 

 continually employed for more than four months. And it is a remark- 

 able fact, that, though neither Colonel Fasley himself, nor any officer 

 or man under his command, had ever used such a Ijattery before, yet, 

 jn consequence of the very clear directions received from Mr. Faraday 

 and Professor Daniell, they succeeded, on the very first trial of their 

 hattery, in firing small charges, both in air and in a bucket of water, 

 3n the niamier usual in a lecture-room. But when they took those 

 precautions, which appeared absolutely necessary to insure the suc- 

 cess of similar explosions at the bottom of the Medway, at the distance 

 of .500 feet, which they eonsitlered sufficient for the safety of the 

 operators, in firing the largest possible charge or charges in deep 

 water, so many failures took place, that atone time idtimate success 

 ■appeared a matter of doubt: for it often happened that the arrange- 

 ments which never failed in air or under ground failed in water; and 

 those which succeeded in a pond near their barracks failed in the 

 Medway. At last, after trying more than a hundre<l different experi- 

 ments, they succeeded in reducing the operation of igniting guiipow der 

 liy the voltaic battery, both under ground anil under water, to as much 

 certainty as their former mode of tiring mines in dry soil. They did 

 not a<lopt any of Dr. Have's arrangements, because it did not appear 

 that he had ever used them under water. 



" To record their various experiments, which commenced on the 23rd 

 of November, 1S3S, would be tedious and useless: suffice it to say, 

 that they first succeeded in firing an exjierimental charge of 1 lb. of 

 powder only, at the bottom of the Medway, at the distance of 500 feet, 

 on the 7th "of February, ISSO; that they fired their first mine, at the 

 same distance, witli a charge of 30 lbs. of powder, which, having a 

 very small line of least resistance, blew up a field-work in presence of 

 Colonel Warre, the Commandant, and most of the officers of the garri- 

 son of Chatham, and numerous other spectators, on the 11th of 

 February ; that they fired a charge of 45 lbs. of powder at the bottom 

 of the Medway on the 16th of March; and that they fired a eliarge of 

 40 lbs. of powder at the bottom of the Medway on the iSrd of March, 

 by which they knocked to pieces a sham wreck. These two last ex- 

 plosions, each of which was also at the distance of 500 feet, took 

 place in the presence of numerous sjiectators, chiefiy officers of the 

 garrison, whom Colonel Pasley invited to attend, not only from being 

 of opinion that the voltaic battery may become extensively usefid for 

 militar^- purposes, but also from a desire to fix the time when each 

 peculiar process was first publicly carried into effect. In reference to 

 this point, it was rather mortifying to him, that after he thought every- 

 thing was right, the first mine which he invited the officers of the 

 garrison of Chatliam to attend entirely failed, owing to a very small 

 and delicate piece of platinum w ire, which is always placed inside of 

 p;u'h charge, having been broken liy some accident, so that the voltaic 

 circuit was incomplete. This failure, which never occurred before 

 nor since, in any of his numerous experiments, led to the precaution of 

 always testing each charge, by ascertaining, with two or, at the most, 

 three cylinders or cells of the voltaic battery, whether the connexion 

 between the two copper conducting w ires and the platinum wire within 

 the charge is perfect, which is known by the battery decomposing 

 water, a process recjniring much less power than is necessaiy for 

 igniting gunpowder, and which is done in a small glass tnbe to contain 

 tlie water, prepared and used as directed in article Olll (d' Faraday's 

 Chemical ManipuUition, (page 453.) If no decomposition take place. 



which is, of course, known by the wires not producing any effect when 

 brought near to each other within the water, but without actual con- 

 tact, as directed by the author, the platinum wire in the charge must 

 necessarily be broken, and the case containing the powder must there- 

 fore be opened again, to make the connexion good ; but if air-bubbles, 

 forming anil ascending in the water, should sliow that decomposition 

 is taking place, the connexion of the conducting w ires and of the piece 

 of platinum wire must be perfect. There is another reason for not 

 bringing the wires in the proof tube into contact, not stated by Mr. 

 Faraday, who was writing without reference to the presence of gun- 

 powder in any part of tlie circuit, namely, that such contact might 

 ignite the charge, if the battery were strong enough ; in order to avoid 

 all risk of wliit'li, two cells should always be tried first, this number 

 never having been known to ignite gunpowder in any of the experi- 

 ments now alluded to; antl if two should not act upon the water, let 

 three be tried with caution, which number, though it may ignite gun- 

 powder near to the battery, that is through a very short circuit, will 

 not ignite it wdien the proof tube for decomposing water forms ;dso a 

 part of the circuit, because the action on the piece of platinum wire, 

 which passes through a cork coated with wax at the bottom of the 

 tube, diminishes the force of the voltaic electricity upon the other 

 piece of platinum wire within the charge. In testing their experi- 

 mental charges, therefore, by tlie decomposition of water, great caution 

 was always used by the engineers at Chatham, after the accident above 

 alluded to, which caused them to have recourse to this expedient. 

 This failure t;iking place on Saturday afternoon, the 9th of February, 

 caused the experiment to be put off till the Monday following, the 11th 

 of February, when the mine was fired successfully as before mentioned, 

 the charge being placed under the field work that was to be blown up, 

 and the conducting wires being led from thence, entirely underground, 

 in a trench cut for the purpose about a foot deep, to the battery, at 

 the above-mentioned distance of 500 feet. 



"It is rather curious, that the first inteniled explosion at the bottom 

 of the Medway, to wliich Colonel Pasley invited the garrison, should 

 also have failed, which was caused by an unforeseen circumstance. — 

 One of the officers under his command, who had fitted up the charge 

 and made all the arrangements for the experiment, having been unex- 

 pectedly required to attend an inciuiry, by.an order from the Inspector- 

 General of Fortifications in London, and having forgotten to mention 

 to another officer, who was therefore suddenly appointed to execute 

 if, one of the precautions necessary, and which had been provided for, 

 namely, to secure the conducting wires leading into the charge against 

 any strain tending to separate them from the canister containing it. 

 From the omission of this precaution, the head of the canister was 

 pulled open by the strain alluded to in a strong tide, and all the pow- 

 der spoiled. 



" Several officers residing in or near the metropolis, some of whom 

 were Members of Parliament, as well as several men of science, and 

 members of the institution of civil engineers, having expressed their 

 desire to be present at the great explosion, by which it was proposed 

 to blow up a sham wreck, Colonel Pasley appointed Saturday, at lialf- 

 past two o'clock, at which hour he knew 'that they might arrive without 

 inconvenience, and return to London after the experiment, if necessary. 

 The plan of operation, of which he circulated iirogrammes, announced 

 that the whole jiroceeiling necessary should be done in presence of the 

 spectators. His first experiment, announced for the 9th of March, 

 which would have been executed at high water, having failed, he ap- 

 pointed Saturday next, the Kith of March, for repeating it, on which 

 occasion the ebli of a spring tide flowed with so much violence at the 

 hour apjiointed for commencing, that the charge, when let down to the 

 bottom of the river to grapple with the supposed wreck, could not be 

 brought in contact with it; and though the voltaic battery succeeded 

 in producing the desired explosion, the wreck remained uninjured. 

 On this account, therefore. Colonel Pasley appoiuteil a repetition of 

 the same experiment on the Saturday next following, which being 

 conqiletely successful shall now be described. 



" The b'atterv used was on Professor Daniell's improved construction, 

 as before stated, which from its admiralile property, in which it sur- 

 passes all former voltaic batteries, of retaining its power iindiminished 

 for several hours, he has named the cons/aiit hatltnj. The copper 

 cylinders, or cells, were of the largest size that has been used, namely, 

 21 inches high by 3i inches in diameter, with zinc rods, i^c, of pro- 

 liortional dimensions. Colonel Pasley had ordered it to be fitted up 

 with iiorcelain cylinders inside to contain the zinc rods, in preference 

 to membranes; but on trial he found that the former were continually 

 breaking in spite of every precaution, and therefore he adopted the 

 latter, which are ox gullets, and which only cost as mmiy pence as the 

 former do shillings. The cimducting wires, rather more than 500 feet 

 long, were of copper, one-fiftli of an inch in diameter, which were 



