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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 are signally different, is evident from their dissimilar properties. I have thus endeavoured to give a brief outline of some of the peculiarities attending this new process, which I offer to the lovers of science and nature. That it is susceptible of great improvements I 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 subject (says Mr. Talbot) naturally divides 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 surface; 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 throughout 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 water. When dry, the paper is fit for use. He has found, by experiment, that there is a certain 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 effect 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 leaves 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 this 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 variations 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 show's, that the attempt to give it sensibility has been earned 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 w r hen much attenuated. Having, therefore, prepared a number of sheets of paper, slightly different 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 very 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 very 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 sunshine. 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 pictures in this way, with proper management, is very beautiful and lasting. The specimen of lace, which Mr. Talbot exhibited to the society, and which was made five years ago, was preserved in this manner. But his usual 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 drying it. It is sufficiently singular that 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 colour 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', which 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. Ship-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 are occupied by vessels, of various tonnage, in process of building; and more frames would be laid down if the builders could undertake the work. The ship-builders along the w'est and the east coast are equally busy, and have frequont occasion to refuse proffered contracts for building vessels. All these circumstances show that the shipping interest is in a very flourishing state,—Liverpool paper. NELSON MEMORIAL. Merely a single visit to Mr. Rainy’s Gallery—just before our presen number was going to press, and when of course we ourselves were greatly hurried,—does not enable us to enter into any critical remarks on any of the designs and models individually, or even to give a general opinion as to the average talent displayed in this competition, further than that satisfactory as the coup d'ceil of the exhibition itself is, we observed very few designs characterised by originality of invention or propriety of adaptation to the intended site. On the contrary, the larger majority, we apprehend, would he found, on deliberate exami nation, to be but poorly calculated 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 Committee. The design makes no pretension whatever to originality, being no more than a fluted Corinthian column, 174 feet high, on a pedestal ornamented with reliefs, and surmounted by a statue 17 feet high, 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 two other prizes are by their respective authors:— DESIGN, BY E. H BAILY, 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 Genius of Britain, hailing 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 Rock 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 FOWLER, ARCHITECT, AND R. W. SIEVIER, SCULPTOR. To which the committee propose to award 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 convej the feeling or produce the effect intended by a Monument, designed to commemorate any celebrated character or event. On the other hand a Statue or Sculpture Groupe 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 rostrated decorations 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 massiveness, 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 against the four fronts of the pedestal, are designed to represent Britannia, Caledonia, Hibernia, and Neptune, distinguished by 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 oulogium of the hero,—some attempt at which, by way of illustration, is made 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 inscription, 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 vessels, to give the rostrated character, enriched with festoons of oak and marine ornaments. The middle compartment of the structure contains on the four faces of the dado simply the names of the four principal actions in which Nelson was en gaged ; and in the panel over each is a representation in Basso relievo of some striking incident, in each battle—the front being distinguished by the grand