1 839.] 



Till': CIVIL I^NClNEIiil AND ARCHITECT'S JOURNAL. 



-10.5 



wastiiig, from tlie cause to which we have alhuled ; ami as a further 

 corrnboratioii of our opinion, we may mention tlvat, about the iirst 

 spring tide after the coui])letion of the large groyne, the sea, obstructed 

 by the beach which the erection had caused, was thrown with such 

 additional impetus upon the coast to the eastward, as not only to 

 sweep the beach away, and to bLvve in an unusual manner the rocks, 

 but also to undermine and tlu'ow down many tons of a projecting part 

 of the clitfto the eastward.* 



The clitl's, extending from Hastings to Clift''s End, a distance of six 

 miles, formerly stretched much further to seaward, and by obstructing 

 the parallelism of the current, caused it to excavate a bay in the valley 

 to the eastward, proportioned to the extensiveness and jierpendicular 

 obstruction of ihe cliffs adverted to. As recently as the reign of Queen 

 Elizabeth, the sea appears to have flowed as high as the town of Win- 

 chelsea, and to have insulated the cliff upon which that of Rye is 

 posited. t)nr opinion in this case is further contirmed by old maps 

 attached to Camden's Britannia, which represent the towns now men- 

 tioned as almost insular. The destruction of Old Winclielsea, whicli 

 is buried in the sands to the south of Camber castle, may easily be 

 explained upon the theory of the erpralizing tendency of the channel 

 currents, which it has been our object to establish and to illustrate. 

 It would be easy to multiply examples, and it was rather a remarkable 

 coincidence that, in our last number, there were two paragraphs from 

 distant parts of the coast relating to encroachments of the sea — one 

 respecting the neighbourhood of Penzance, cimtirmatory of our jirin- 

 ciple ; and another stating that, as the aeciunulation of beach at 

 Dungeness point augmented, the undermining of the Martello towers 

 near Hythe, in the bay to the eastward, by (I'le sea, proceeded, with a 

 ju'obability of many acres of land being speedily swallowed up by the 

 element. 



Without further examples we trust we have not only assigned a 

 satisfactory reason for the encroachments and recessions of the sea, 

 and at the same time, by an easy deduction, hinted at the means 

 whereby land may, Ijy the construction of groynes, be recovered to the 

 westward, or, if necessary, excavated on the side opposed to the pre- 

 vailing current by the action of the waves, but have also shown that 

 no extensive infringement of the coast by the waters need he appre- 

 hended ; and that tlie irregularity of the ebb and flow of the tide for 

 centuries past, has been less in proportion than the disturbance of 

 water in a \essel w'hen carried by the steadiest hand, thereby demon- 

 strating the onuiipotence of the divine and sublime injunction — 

 "Hitherto shalt thou come, but no further; and here shall thy proud 

 waves be staid." 



ENGRAVINGS IN RELIEF FROM COPPERPLATES BY .MEANS OF 

 VOLTAIC ELECTRICITY. 

 Wk lately imblislied M. Jacoln's letter to Mr. Faraday, in which he de- 

 scribed his atteniiits to copy in relief engraved copperjilatcs, by means of vol- 

 taic electricity. We have since received a communication from Mr. Thomas 

 Spencer, of Liverpool, from which it appears, that that gentleman has for 

 some time been iiulependeutly engaged on the same sulyect; and that he 

 has not only succeeded in doing all that M. Jacolji has done, but has suc- 

 cessfully overcome those difticulties which arrested the progress of the latter. 

 It is unnecessary here to enter on the question of priority between these gen- 

 tlemen. To Mr. Spencer nmch credit is certainly due for having investigated, 

 and successfully carried out, an application of voltaic electricity, the value of 

 which can hardly lie questioned. The objects which Mr. Spencer says he 

 proposed to ett'ect, were the following : — " To engrave in relief upon a plate 

 of copper — to deposit a voltaic copperplate, having the lines in relief — to ob- 

 tain a fac-simile of a medal, reverse or obverse, or of a bronze cast — to obtain 

 a voltaic impression from plaster or clay — and to midtiply the number of 

 already engraved copperi)lates." The results which he has olitained are very 

 beautiful ; and some copies of medals which he has forwarded to us are re- 

 markably sharp and distinct, jiarticularly the letters, which have all the ap- 

 pearance of ha\ing been struck by a die. Without entering into a detail of 

 the steps by which Mr. Spencer brought his process to perfection, many of 

 which are interesting, as showing how slight a cause may modify the result, 

 wc shall at once give a description of his process. Take a plate of copper, 

 such as is used by an engraver ; solder a piece of copper wire to the hack 

 part of it, and then give it a coat of wax — this is best done by heating the 

 plate as well as the wax — then wi-ite or flraw the design on the wax with a 

 black lead pencil or a ])oint. The wax must now be cut through with a 

 graver or steel point, taking special care that the copper is thorongh exposed 

 in every line. The shape of the tool or graver employed nuist be such that 

 the line made are not V-shaped, but as nearly as possible with parallel sides. 

 The plate should next be immersed in dilute nitric acid — say three parts water 

 to one acid : it will at once be seen whether it is strong enough, by the green 



* Lieut. -Col. Williams, in bis scientific paper on "Ihc Law.s which govern 

 the course nf the Shingle on the 8 K. coast, anil liinls upim K\ e anil Dover 

 llarbom-s," noliccs the general tendency of groynes lo collcci the beach on 

 the western, and tn clear it away on the opposite side, owing lo the prevail- 

 ing current from the suuih-east. 



colour of the solution and the bubbles of nitrons gas evolved from the copiicr 

 Let the plate remain in it long enough for the exposed lines to get shgblly 

 corroded, so that any minute portions of wax which nuglit remain may be 

 removed. The plate thus prejiarcd is then placed in a trough separated into 

 two divisions by a porous partition of plaster of Paris or earthernwarc — the 

 one division being lilled with a saturated solution of sulphate of copper, and 

 the other with a saline or acid solution. The plate to he engraved is placed 

 in the division containing the solution of the sulphate of cojijier, and a plate 

 of zinc of equal size is pl.aced in the other division. .V metallic connexion is 

 then made between the copper and zinc plates, by means of the copper wire 

 soldered to the former ; and the voltaic circle is thus completed. The ajipa- 

 ratns is then left for some days. .\s the zinc dissolves, metallic cojjpcr is 

 precipitated from the solution of the sidphate on the copper plate, wherever 

 the varnish has been renmvcd by the engraving tool. .Vfter the voltaic coi)- 

 per has been deposited in the lines engraved in the wax, the surface of it will 

 lie found to be more or less rough, according to the tpiickness of the action. 

 To remedy this, rub the sin-face with a piece of smooth flag or jitimice-stone 

 v^ith water. Then beat the iilatc, and wash off the wax grounil with spirits 

 of turpentine and a brush. The plate is now ready to be printed from at an 

 ordinary press. In this process, care mtist be taken that the surface of the 

 copper in the lines be perfectly clean, as otherwise the de))osited copper i\ ill 

 not adhere with any force, but is easily detached when the wax is renmved. 

 It is in order to ensure this perfect cleanness of the copper, that it is immersed 

 in ddute nitric acid. Another cause of imperfect adhesion of the deposited 

 copper, which Mr. Spencer has pointed out, is the presence of a minute por- 

 tion of some other metal, such as lead, which, by being precipitated before 

 the copper, forms a thin tilm, which jivevents the adhesion of subsequently 

 deposited copper. This circiunstance may, however, be turned to advantage 

 in some of the other aiiplications of Mr. Spencer's process, where it is de- 

 sirable to prevent the adhesion of the deposited copper. In copying a coin 

 or medal, Mr. Spencer describes two methods : the one is by depositing vol- 

 taic copper on the siu-face of the medal, and thus forming a nnjulil, from 

 which fae-similes of the original nicihd may readily be obtained by prccijii- 

 tating copper into it. The other is even more expeditious. Two pieces of 

 clean milled sheet lead arc taken, and the medal being placed between them, 

 the whole is subjected to prcssm-o in a screw press, and a complete mould of 

 both sides is thus formed in the lead, showing the most delicate lines perfect 

 (in reverse.) Twenty, or even a hundred of these, may be so formed on a 

 sheet of lead, and the'eoppcr deposited by the voltaic process with the greatest 

 facility. Those portions of the surface of the lead which arc between the 

 mould's, may be varnished to prevent the deposition of the lead, or a whole 

 sheet of voltaic copper having been deposited, the medals may aftcrwar s be 

 cut out. When copiier is to he deposited on a copper mould or mcdal,care 

 must be taken to prevent the metal deposited adhering. This Mr. Spencer 

 ctfects by heating the medal, and rubbing a small portion of wax over il. 

 This wax is then wiped off, a sufficient jiortion always remaining to prevent 

 adhesion. Enough has been said to enable any one to repeat and follow up 

 Mr. Spencer's interesting experiments. The variations, modifications, and 

 adaptations of them are endless, and many new ones wUl uatmaly suggest 

 themselves to everv scientific reader. — Athenceum. 



Traksferrin'g Impressions oi- old Prints. — One of the most ingenious 

 inventions we have witnessed for many a day is a process invented by Mr. 

 Joseph Dixon, for transferring impressions to stone. The discovery \yas 

 made some seven or eight years since, and, by its means, new and exact im- 

 pressions of the leaves of old books, bank bills, engravings, &e., may be ob- 

 tained in an incredibly brief space of time. The celerity and exactness of 

 the work arc tndy remarkable. X bank bill was transferred by Mr. Uixon, 

 in presence of the otKcers of a bank, with so much fidehty and precision that 

 the very signers of the bill could not tell the ditl'erence between the copies 

 and the oiigiaal. It is due to Mr. Dixon to state, that he has obtained a 

 patent for the process by which bank bills can be protected from his own 

 invention, shoidd it ever fall into the hands of rogues. The importance of 

 this chscovery is in nowise inferior to that of the Daguerreotype, of which 

 we have heard so much within the last year. — New York Mirror — [We gave 

 a description of a sinular invention, by two Freuehmen, in the Journal for 

 .Vugust last, page SOS. Editor C. E. and .\. Jounial.] 



How TO Stop a Run.vway Horse. — Jlr. Thomas, of St. James's-strect, 

 has just perfected an invention, the object of which is to stop the progress 

 of horses which have taken fright. The ajqiaratus is thus described by Mr. 

 Thomas himself :—" On the nave of the wheel is fixed a small gmi-metal 

 wheel ; in front of the axle runs a steel spindle, with a small cog attached ; 

 over the spindle is a cylinder, and to which a check-string is atilxed. The 

 moment it is put in action the spindle advances, and the cog revolves gradu- 

 ally romid the gun-metal wheel, which is fixed on the nave, carrying with it 

 reins leading from the horse's head, composed of cat-gut, or of patent cord, 

 covered with leather. ,\s the wheel revolves, the cylinder, which is about 

 an inch in diameter, is gathering up the reins, until the horse is brought to 

 a stand-still; when, by letting'loosc the check-string, the horse's head is 

 inuncdiately free." .Mr. Thomas has \ery appropriately named his most 

 valuable invention a " Carriage Safety, or Traveller's Life Preserver." — ll'ater- 

 fhnl Po/jer. [We believe this lo be a sinular invention to one patented by 

 a gentleman of the nanu; of Cook, and aiqilied to several can iages, and to a 

 Brighton stage coach, about U) or 12 years ago; at that time orders were 

 received for the apparatus at a shop in Long Acre. — Eo. C. E. & .V. Jour.] 



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