104 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[March. 



and when we happen to come near the limit which separates the two cases, it 

 depends upon exceedingly small and often imperceptible circumstances, which 

 of the two compounds shall be formed. That they are both definite compounds, 

 is of course at present merely my conjecture ; that they arc signally different, 

 is evident from their dissimilar properties. 



I have thus endeavoured to give a brief outline of some of the peculiarities 

 sttending this new process, which I oft'er to the lovers of science and nature. 

 That it is susceptible of great improvements T have no manner of doubt ; but 

 even in its present state I believe it will be found capable of many useful and 

 important applications besides those of which I have here given a short account. 



The sxibject (says Mr. Talbct) naUually dividi^s itself into two heads — 

 the preparation of the paper, and the means of fixing the design. In order 

 to make what may be called ordinary photogenic paper, the author selects, 

 in the first place, paper of a good firm quality, and smooth stu-facc ; and 

 thinks that none answers better than superfine writing paper. He dips it 

 into a weak solution of common salt, and wipes it dry, by which the salt is 

 uniformly distributed thi-oughout its substance. He then .spreads a solution 

 of nitrate of silver on one surface only, and dries it at the fire. The solu- 

 tion should not be saturated, but six or eight times diluted with wafer. 

 When dry, the paper is fit for use. He has found, by experiment, that 

 there is acertain proportion between the quantity of salt and that of the 

 solution of silver which answers best, and gives the maximum effect. If 

 the strength of the salt is augmented beyond this point, the ett'ect 

 diminishes, and, in certain cases, becomes exceedingly small. This paper, 

 if properly made, is very useful for all ordinary photogenic purposes. For 

 example, nothing can be more perfect than the images it gives of lea\es 

 and flowers, especially with a summer sun. The light passing through 

 tthe leaves delineates every ramification of their nerves. If a sheet of 

 paper, thus prepared, be taken and washed with a saturated solution of 

 salt, and then dried, it will be found (especially if the paper has been kept 

 some weeks before the trial is made), that its sensibility is greatly 

 diminished, and, in some cases, quite extinct. But if it be again washed 

 ■with a liberal quantity of the solution of silver, it becomes again sensible 

 to light, and even more so than it was at first. In tliis way, by alternately 

 washing the paper with salt and silver, and drying it between times, 

 Mr. Talbot has succeeded in increasing its sensibility to the degree that is 

 requisite for receiving the images of the camera obscura. In conducting 

 this operation, it will be found, that the results are sometimes more, 

 and sometimes less satisfactory, in consequence of small and accidental 

 vaiiations in the proportions employed. It happens sometimes that the 

 chloride of silver is disposed to darken of itself, without any exposure to 

 the light — this shows, that the attempt to give it sensibility has been 

 carried too far. The object is, to approach to this condition as near as 

 possible, without reaching it; so that the substance may be in a state 

 ready to yield to the slightest extraneous force, such as the feeble impact 

 of the violet rays when much attenuated. Having, therefore, prepared a 

 number of sheets of paper, slightly difi'erent from one another in the com- 

 position, let a piece be cut from each, and, having been duly marked or 

 numbered, let them be placed side by side in a vei-)' weak diffused light, 

 for about a quarter of an hour ; then, if any one of them, as frequently 

 happens, exhibits a marked advantage over its competitors, Mr. Talbot 

 selects the paper which bears the corresponding number to be placed in 

 the camera obscura. 



With regard to the second object — that of fixing the images — Mr. Talbot 

 observed, that, after having tried ammonia, and several other re-agents, 

 with reiT imperfect success, the first which gave him a .successful result, 

 was the iodide of potassium, much diluted with water. If a photogenic 

 picture is washed over with this liquid, an iodide of .silver is formed, which 

 is absolutely unalterable by svuishine. This process requires precaution ; 

 for, if the solution is too strong, it attacks the dark parts of the picture. 

 It is requisite, therefore, to find, by trial, the proper proportions. The 

 fixation of the picttires in this, way. with proper management, is very 

 beautiful and lasting. The specimen of lace, wliich Mr. Talbot exhibited 

 to the society, and which was made five years ago, was preserved in this 

 manner. But his ustial method of fixing is different from this, and some- 

 what simpler — or, at least, requiring less nicety. It consists in immersing 

 the picture in a strong solution of common salt, and then wiping off the 

 superfluous moisture, and drj'ing it. It is sulRciently singular thtit the 

 same substance which is so useful in giving sensibility to the paper, should 

 also be capable, under other circumstances, of destroying it ; but such is, 

 nevertheless, the fact. Now, if the picture which has been thus washed 

 and dried; is placed in the sun, the white parts colom- themselves of a pale 

 lilac tint, after which they become insensible. Numerous experiments 

 have shown the author that the depth of this lilac tint varies according to 

 the quantity of salt used, relatively to the quantity of silver; but by pro- 

 perly adjusting these, the images may, if desired, be retained of an absolute 

 whiteness. He mentions, also, that those preserved by iodine are always 

 of a very pale primrose yellow, v\-hieh has the extraordinary and very 

 remarkable property of turning to a full gaudy yellow, whenever it is 

 exposed to the heat of a fire, and recovering its former colour again, when 

 it is cold. 



Sliip-building. — The ship-builders of Liverpool, have seldom, if ever, been so busy 

 as they are at present. All the yards on both sides the Mersey aj-e occupied by 

 vessels, of various tonnage, in process of buiWing; and more fraiues wouldbelaiJ down 

 if the builders could undertake the work. The ship-buiiders along the west and the 

 east coast are equally busy, and have frequent occasion to refuse proffered contracts 

 for building vessels. All these circumstances show that the shipping interest is iu a 

 very flouiishing itiW -^Liverpool paper. 



NELSON MEMORIAL. 

 Merely a single vi,it to Mr. Rainy's Gallery — ^^just before our presen 

 number iv.is goius; to press, and when of course we ourselves were 

 greatly hurried, — does not enable us to enter into any critical remarks 

 on any of llie desiitns and models individually, or even to give a general 

 opinion as to the average talent displayed in this competition, further 

 tlvin that satisfactory as the coup d'a:it of the exhibition itself is, we 

 observed very few designs characterised by originality of invention or 

 propriety of adajjtation to the intended site. On the contrary, llic 

 larger majority, we apprehend, would be found, on deliberate exami- 

 nation, to be but poorly calcitlaled to suit either the area itself, or the 

 surrounding buildings. 



DESIGN BY W. RAILTON, ARCHITECT. 



To which the first premium is proposed to be adjudged by the first Connnittee. 



The design makes no pretension whatever to originality, being no more 

 than a fluted Corinthian column, 1 74 feet high, on a pedestal ornamented with 

 rehefs, and surmounted by a statue 17 feet bigb, consequently for want of 

 some basement or .substructure will be apt to look too small, except as merely 

 a lofty central ornament in the square. 



The following description of the tsvo other prizes are by their re.ijpective 

 authors: — 



• DESIGN, BY E. H EAILY, R.A. 



To which the committee propose to award the second prize. 



Description. — An Obelisk raised to the memory of Nelson by his 

 grateful country. At the base, our great Naval Commander is repre- 

 sented supporting the Imperial Standard; on his left stands the Cienius 

 of Britain, bailing with affection the Hero of Trafalgar ; his attendant. 

 Victory, being seated on his right. At the back of the Obelisk rests the Nile — 

 Neptune with the subordinate Deities of the Ocean, form a Triumphal Pro- 

 cession round the Hock on which the Monument is placed, thereby indicating 

 that the Victories of Nelson were as extensive as the Element on which h 

 fought. 



Dimensions.— The height of the Monument is intended to be 60 feet ; the 

 diameter of the steps the same extent ; and the height of Nelson to be nine 

 feet, the other figures in proportion, as in the sketch. 



Estimate. — To execute the whole monument in Ravaccioni Marble, (the 



same as the arch before Buckingham Palace is built of) 22,000/ if executed 



in Bronze, .30,000/. 



DRAWINGS AND MODEL BY CHARLES POWLER, ARCHITECT, AND R. W. 

 SIEVIER, SCULPTOR. 



To which the committee propose to avrard the third prize. 



This design has been composed upon the principle of combining Architec- 

 ture and Sculpture; with a view to obtain a more striking effect from their 

 union than either is calculated to produce separately ; the one by its forms and 

 mass, to arrest the attention and make a general impression, which may be 

 heightened and perfected by the more refined and interesting details of the 

 other. It would appear from the result of existing instances that a mere 

 structure cannot properly convey the feeling or produce the effect intended by 

 a ISIonument, designed to commemorate any celebrated character or event. 

 On the other hand a Statue or Sculpture Croupe is inefficient for want of mass 

 and general form ; the former is appreciated as a distant object, and the latter 

 only on close inspection. The desideratum, therefore, lies in avoiding these 

 objections, or rather in combining the advantages which peculiarly belong to 

 each art, so that the many who pass by may be struck with the general aspect 

 of the Monument, and the few who may pause to examine its details may find 

 their first impressions carried forward and perfected by the beauty and 

 significance of its historical illustrations. 



With respect to the design now submitted, the endeavour has been to render 

 it characteristic and appropriate to the occasion, avoiding plagiarism but 

 without affecting novelty. The rostraied decoraiions of the pedestal, and its 

 accessories proclaim it at once to be a naval trophy; and the hero to be com- 

 memorated will be not less plainly indicated ; whilst the sculpture and other 

 details will set forth his achievements. 



In regard to the structure, simplicity and strength are the distinguishing 

 qualities of the basement, which is proposed to be constructed of granite, in 

 large blocks, so as to be striking for their massivcness, solidity, and giving 

 dignity to the superstructure. The pedestals at the angles of the platform are 

 to be surmounted with piles of trophies executed in bronze, and crowned with 

 lamps to light both the area and monument ; massive granite basins are set to 

 receive the running fountains on three sides, the fourth being reserved for an 

 entrance to the structure within. The colossal figures seated agaiuil the four 

 fronts of the pedestal, are designed to represent Britannia, Caledonia, Hibcrnia, 

 and Neptune, distinguished bv their appropriate insignia and attributes. 



On the south front of the pedestal, and at a legible distance from the spectator, 

 is proposed to be inscribed a brief eulogium of the hero, — some attempt at 

 which, by way of illustration, is madi? in the drawing, without presuming to 

 anticipate that delicate task, which will properly devolve upon other and more 

 able hands. The opposite side is intended to contain the historical or matter- 

 of-fact inserijition, comprising also a record of the erection of the monument. 

 The other two sides are to have each a shield of arms in relief, encircled by a 

 wreath. The cap or cornice of the lower pedestal is decorated by antique 

 prows of vessc-ls, to give the rostrated character, enriched with festoons of oak 

 and marine ornaments. 



The middle compartment of the strueliire contains on the four faces of the 

 dado simply the names of the four principal actions in which Nelson was en- 

 gaged ; and in tlip panel over each is a representation in Basso reliero of some 

 striking incident, in each battle— the front being distinguished by the grand 



