171 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



May, 



titles, and liad been marked " Chubb's Patent," until the makers were 

 stopped by legal process, when it was ruled, both at law and equity, that, 

 although after the expiration of a patent, any person might manufacture 

 the article, he had no riglit to pirate a peculiar trade mark, or to use a dis- 

 tinctive stamp, which was irrespective of any patent right. 



The locks used at Pentonvillc Prison were instanced as uniting goodness 

 and safety with extreme cheapness; but it was admitted that the workman- 

 ship was very inferior to that of Cbubb's locks. 



It was also asserted that Uavis's locks, invariably used on the Cabinet 

 Dispatch-boxes, which frequently contained important secret papers, were 

 never found to be out of order, or to be susceptible of being picked. 



To this it was replied, that Mr. Chubb was prepared to produce a work- 

 man, who, without having ever previously seen the locks on the Cabinet 

 Dispatch-boxes, would open any number, on being allowed half an hour for 

 each; ami that the same might be done more easily with the Pentonville 

 Prison locks. 



In summing up the discussion, it was stated to be the duty of the Insti- 

 tution to express the conviction, of a veritable Chubb's lock never having 

 been picked cither in Great Britain or on the other side of the Atlantic ; 

 that it did, in fact, combine that strength, simplicity, and security, without 

 which the most ingenious locks were utterly useless ; that it possessed the 

 merit, in the production, of never, through fear of competition, having 

 reduced the quality of the workmanship to meet a reduced price, and thus, 

 by a due consideration of the workmen employed in the manufacture, the 

 men had been taught to he as jealous of their master's reputation for good 

 work as he could be of himself, and that thus the merited reputation of the 

 work had been, and was still, maintained. 



April 2Z. — The paper read was a "Description of the Insistent Pontoon 

 Bridge, at the Dublin Terminus of the Midland Great Western Railway of 

 Ireland." By Mr. R. Mallet M. Inst. C.E. 



This bridge was stated to be situated on the line of approach from the 

 city to the terminus, and formed a passage over one branch of the Royal 

 Canal, where it crossed the Phibsborough-road, upon the Foster Aqueduct. 

 By the act it was provided, that the navigation of the canal should be as 

 free and unimpeded as possible; and from the circumstance of there being 

 only a height of 16 inches between the intended surface of the road and 

 that of the water of the canal, it necessarily involved the placing of some 

 kind of moveable bridge, of rather peculiar construction. After due con- 

 sideration, the one described in the paper was designed and adopted, as being 

 more suitable to the peculiarities of the situation than any other, owing to 

 the water.channel being oidy 17 ft. 4 in. in width, and that the passage to 

 be made across it required to be at least 50 feet in breadth. 



The general idea of this form of moveable bridge was that of a pontoon, 

 or flat-bottomed boat, constructed of iron; the breadth being nearly equal 

 to that of the water space to be crossed, and the length about equal to the 

 width of roadway required. The deck beams of this pontoon projected 

 over the sides, and rested while in situ, upon a rabbate, or continuous re- 

 cess, formed along the top course of each quay-wall, but while the pontoon 

 ■was floating light, the projecting deck-beam's were 2 inches clear of this 

 rabbate, and the roadway platfoim, constituting the deck of tlie pontoon, 

 was elevated to an equal height above the level of the top of the quav-walls, 

 or land on each side; in this state the pontoon could he freely and' readily 

 pushed along the canal, for a distance of rather more than its own length, 

 until it was brought opposite to a lyc-by, provided by increasing the width 

 of the canal at this point, and being put therein, the navigation was per- 

 fectly free. 



As a pontoon afloat would form a very unstable roadwnv for carriages, 

 means were provided for allowing it to settle down in the 'water, and rest 

 firmly upon tlie rabbates; and also for again raising it rapidly, so as to float 

 clear of tlie rabbates, and enable it to he moved away into tlie lye-by. I'or 

 this purpose two large valves were jilaced in the bottom of the pontoon, one 

 near eacli end, by which water was allowed to enter, and sink the pontoon, 

 until It hung upon the projecting deck-beams. For removing this water, 

 when it was required to float the pontoon, a large syphon, of a particular 

 construction, was provided, which was capable of being brought instantiv 

 into use, and of being as quickly detached, when a suftiL-iency of water had 

 been withdrawn to enable the pontoon to be moved. These operations were 

 stated to he performed very readily by one man, the navigation being cleared 

 in four minutes, and the roadway restored in less than three minutes. 



The details of the construction of the pontoon, of the svphon, and all 

 other parts of the work were then minutely given; also the total cost of the 

 structure, which, exclusive of the masonry,' was 1125/., that of the masonrv 

 being about 150/.; and it was stated to have continued in use, with perfect 

 satisfaction, since its completion in February, 1847. 



This form of construction was considered lo be applicable in situations 

 where a comparatively narrow water channel had to be crossed by a very 

 wide roadway; but as the particular circumstances of other localities might 

 diS'er from the one in question, the author suggested various alterations in 

 the details, so as to meet these exigencies. 



The next paper read was a "Description of a wronght-iron Lattice Bridge, 

 constructed over the line of tlie Rughg and Leamington Raihoay." Bv Mr. 

 W. T. DoYNE, Assoc. Inst. C.E. 



This bridge, which was 150 feet span, carried a public road over the Ilon- 



inghara cutting. It consisted of two girders 156 feet in length, and 10 feet 

 G inches in depth, placed at a distance of 20 feet apart, and connected 

 together by means of wronght-iron transverse girders, and by a system of 

 horizontal diagonal bracing. The bottom of the main girders were formed 

 of two angle irons, and wrought-iron plates, eight in number at the centre, 

 but diminishing to three at the ends, and of such dimensions as to make the 

 efl'ective sectional area at the centre, after deducting the loss by rivet holes, 

 equal to 26 square inches ; that of the top, which was somewhat diflerently 

 constructed, so as the better to resist compression, being equal to 40 square 

 inches. The lattices were formed of a series of bars of spoke-iron, inter- 

 secting each other at an angle of 60°, being crossed at those points, by 

 longitudinal bars, for the purpose of giving additional rigidity, and of 

 making a closer parapet. The transverse girders, 7 feet 6 inches apart, 

 were each formed of a plate of wrought iron, with two angle irons at the 

 top and the bottom ; these were covered with corrugated galvanised iron, 

 one-tenth of an inch thick, upon which concrete, and then a layer of gravel 

 and loam metalling, G inches thick, were laid. This bridge was erected by 

 Messrs. Smith, Smith, and .lames, of Leamington, upon a platform which 

 gave to the girders a camber of 7 inches in the centre, which was reduced 

 to ,Tf inches upon removing the platform. The total cost of the bridge was 

 about .■$,500/. 



During the progress of the works, the author made some experiments 

 upon the strength of rivets of diff'erent sizes, from which it appeared, that 

 the average breaking weight, per square inch of sectional area, was 35-10 

 tons for a chain joint, and 18-82 tons for a lap joint. 



ROYAL SCOTTISH SOCIETY OF ARTS. 



The following communications were made : — 



Remarks on the Positions laid down by Mr. Cousin, in a Communication 

 lately read by him, " On the Philosophy of the Beautiful, and an Analysis 

 of the Principle of Proportion, as applicable to Arcliitecture,^' By Mr. 

 Thomas Purdie, Edinburgh. 



Mr. Purdie stated the principle on which Mr. Cousin seemed to found his 

 doctrines, viz. — that the mind receives a pleasure from certain proportions, 

 whether in the relations existing between the various parts of a building, 

 or in the relations which the notes of a musical chord bear to each other in 

 the number of vibrations required to produce them. That harmony is, 

 therefore, "the perception of these relations," conveyed to the mind in the 

 one case by the eye, and in the other by the ear. 



Mr. Purdie contended that this definition of harmony was only a con- 

 founding of names. That the word harmony is applied to architecture only 

 in a conventional or metaphorical sense, and may therefore be used to convey 

 any meaning which fashion or fancy may happen to dictate. But, whatever 

 harmony in architecture may be, the mind which perceives nothing and 

 knows nothing of the relations of musical notes or of vibrations may receive 

 a pleasure from harmony of the most intense and elevated kind. While the 

 secondary lieauty of harmony is, doubtless, due to its connection with man's 

 deepest feelings and most interesting emotions, its primary beauty can be 

 attributed only to sensation as an ultimate fact in man's mental constitution, 

 and has no more connection with perception of relation than have the prick 

 of a pin or the perfume of a rose. If there were any beauty at all in ratios, 

 the ratio existing between the diameter and circumference of the circle 

 seemed to possess quite as much of that desirable quality as the ratio of one 

 to two, or three to four. If harmony, he contended, were the perception of 

 relation, and if those relations only were beautiful which are simple and 

 definite, what would have become of the mathematician engaged in the 

 higher calculus where many of the calculations refer to irrational and even 

 imaginary quantities. A single page of it would evolve an amount of dis- 

 cord sufiieient to drive altogether mad any mathematical devotee who might 

 happen to be cursed with a musical temperament. 



But granting that Mr. Cousin bad established the premises — that har- 

 mony is the perception of relation, and tliat beauty results only from the 

 perception of definite relation — he bad only placed his doctrines in a posi- 

 tion which rendered their complete fallacy the more obvious and apparent. 



Take any number of rectangular forms such as those to which it is pro- 

 posed to apply this system of pro|)ortioning — say two windows of a building 

 with the space between them. Adopt some of those ratios which Mr. Cousin 

 asserts to be beautiful, and apply them to the diagonal lines of these rect- 

 angles. Let the diagonal line of the windows form with the base an angle 

 of 60 degrees, and that of the space between them 67^. These numbers, 

 if the angles be taken as the standard, bear a simple or harmonic ratio to 

 each other, and to a right angle. But it is impossible to suppose that the 

 relations of angles, formed by unseen diagonal lines, which are supposed to 

 be drawn within certain rectangular figures, can serve as the foundation for a 

 system of proportion, or that they can produce so powerful an efl'ect as the 

 relation between the sides, which are visible to the eye; and, unfortunately 

 for this theory, it happens that the sides must of necessity be at variance 

 with Mr. Cousin's proportions in every ease, when the angles are in accord- 

 ance with them. 



In the designs exhibited to the Society, Mr. Cousin, for the most part, 

 adopted the angles as the basis of his harmony ; but he sometimes admitted 

 the proportion of the sides, and at other times he admitted of both in the 



