224 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[July, 



and to regulate the exchange of foreign coin. Of these officers there 

 were anciently three, two in London, at the Tower and Old 'Change, 

 and one in the city of Canterbury. Subsequently another was ap- 

 pointed with an establisliment in Lombard Street, the ancient rendez- 

 vous of the merchants ; and it appears not improbable that the Queen's 

 intention was to have removed this functionary to what was now pre- 

 eminently designated as the Royal Exchange. 



As the Bourse of Antwer|) had furnished a model for close imitation 

 to the projectors of London, the work of the latter was, in its turn, 

 closely followed by the citizens of Amsterdam. The Bourse, which 

 still subsists there, was commenced in KJUS, and opened in 1613. A 

 rectangular area, as in the previous instances, is surrounded by a 

 covered way, formed by forty columns of stone, carrying an upper 

 story and roof exceedingly similar to those before noticed. Tliere 

 are principal entrances on the north and south sides, and the latter 

 lias the addition of a lofty bell-tower and clock. 



To revert to the Royal Exchange of London, it may be noticed that, 

 the original structure having been destroyed in the great fire of IGGli, 

 its successor was erected upon the same site, under the superinten- 

 dence of Mr. Edward Jerman, one of tlie surveyors to the city, at an 

 outlay of £5S,<)62. With the facts affecting the recent destruction of 

 this edifice by fire also, we are all too well acquainted; and with 

 respect to the erection of any structure that may supply its place, 

 It may be sufficient just to state, in conclusion, that the instructions 

 under which the various designs for a new Royal Exchange have been 

 jirepared, have determined that an open a; ea shall be preserved for 

 the use of the merchants, after the manner of the former building, but 

 about one third larger in extent. The Bourse at Paris, the more 

 recently erected Exchange at Glasgow, and the Exchange at St. Pe- 

 tersburg, are all covered buildings. The Exchange at Liverpool, on 

 the other hand, follows the more ancient precedent, retaining the open 

 area and surrounding arcade. As any discussion of the propriety of 

 those instructions that have been issued for the direction of architects 

 on the subject of the new Royal Exchange, would be beside our pre- 

 sent purpose, as would any observations in anticipation of a future struc- 

 ture, we may now close our remarks, w ith a hope that this compresseil 

 statement may afford our readeis some degree of that interest with 

 which the original lecture was received by the audience of the Archi- 

 tectural .Socielv, 



THE ROYAL EXCHANGE. 



Sir — Having taken no part whatever in the competition, or in any 

 of the correspondences which liave appeared in the various public 

 prints relative to the Royal Exchange, and feeling a general disgust at 

 the intemperate manner in which such correspondences are usually 

 conducted, but understanding that the affair appears as far off from 

 settlement as ever, I now crave through the medium of your widely cir- 

 culated journal, the promulgation of the following brief remarks. 



1st. It appears pretty certain, that the plan which will be adopted 

 will conform, as it should, to the lines of the principal adjoining streets, 

 otherwise the frontages of the building would lie awkwardlv w-ith re- 

 gard to them, and more ground would be given up in making the site 

 rectangular than the required accommodation would well allow. It 

 seems therefore that the jilan will be in shape a trapezium. 



2nd. In all plans of this shape which I have seen, (that of Mr. Tite 

 inciudedj, there are a multitude of frregularities, many rooms out of 

 square, some of the largest of them with whole wings sliced off irre- 

 gularly, and many doors, windows, and chimneys seemingly placed at 

 random, all which defects would be evident enough to those who might 

 use such apartments. 



3rd. Now I would undertake to make such a design (merelv by re- 

 membering that there is in the world such an art as Geometry, of which 

 Wren, and his kiixl, made much use, more especially in diliicult cases), 

 which design should have every internal apartment, angle, door, win- 

 dow, and chimney regular. 



4th. To effect this, 1 should need only to cut off from the site, the 

 large ranges of apartments in lines exactly parallel to the principal 

 front of the building. This would leave a smaller trapezium in the 

 centre of the ground. 



5th. Within this smaller trapezium I should place an elliptical court, 

 and in tlie four spandrel spaces which would be left, I should place 

 semi-circular staircases, water-closets, and other offices. 



Otli, The architecture of the elliptical court, I should form some- 

 thing after Inigo Jones's magnificent and universally admired circular 

 Persian court, designed for Whitehall : but instead'of having all the 

 culnmnar statues (say 32 in numberj made similar, which by monotony 

 would displease, 1 would have them each a type of some chief nation 

 trading to London : and if the expense of these Caryatic statues be 



objected to, I doubt not that the merchants engaged in the several 

 trades, would find the difference between the price of them and of 

 plain piers. 



I am, Sir, your very obedient humble servant, 

 Gray's Inn, June 19, 1840. g. 



GEOMETRICAL THEOREM. 



Siu — I believe that the following curious property of a circle has 

 not hitherto been noticed ; or if it has, I am not aware of its existence 

 in any of our works on Geometry. 



Let A B C D E be a circle, of which A C D is anv given segment : 

 Let any number of triangles A B D, A C D, &c. be drawn in this seg- 

 ment, and let circles be inscribed in tliese triangles : their centres F, G, 

 &c. are in the arc of a circle, whose centre is at E, the middle of the 

 arc of the opposite segment A E D. 



DEMONSTRATIOX, 



Join A F, F D, AG, GD; then since F is the centre of the circle, 

 inscribed in the triangle ABD, the lines A F, F D, bisect the angles 

 BAD, B DA. (Euc. B. 4, P. 4). For a like reason A G,GD, bisect 

 the angles CAD. C D A ; hence the angles FAD, FDA, together, 

 are equal to half the angles, BAD, B D A together, and the angles 

 GAD, GDA together, to half the angles CAD, CD A together. 

 Now the angles A B D, A C D, are equal (^being in the same segment), 

 therefore the angles BAD, B D A together, are equal to the angles 

 CAD, CD A together, and as the halves of equals are equal, the 

 angles F A D, F D A together are equal to the angles G A D, G D A 

 together ; that is in the two triangles A F D, A G D, two angles of the 

 one, are together equal to two angles of the other, and therefore the 

 third angle A F D, is equal to the third angle A G D. The same rea- 

 soning will prove, that all angles similarly circumstanced to A FD, are 

 also equal to A G D : therefore, the points A, F, G, D, are in an arc 

 of a circle. 



Join B F, and produce it to cut the opposite circumference in E and 

 join E A, ED; then because the angle A B E, is equal to the angle 

 D B E, the segment A E, is equal to the segment E D, and the chord 

 AE, to the chord ED. Again the angles ABE, E D A, are equal 

 (being in the same segment), and by construction, the angle A D F is 

 equal to the angle F D B, therefore the whole angle ED F, is equal to 

 the two A B F, F D B, that is to the two F B D, F D B, that is to the 

 exterior angle E F D ; therefore the angle E F D, is equal to the angle 

 E D F ; consequently E F, is equal to E D, that is to E A. The same 

 reasoning would prove E F to be equal to a line drawn from G, to the 

 point E. Wherefore the point E is the centre of a circle, of which 

 F and G, as also the centres of all other circles similarly inscribed, are 

 in the circumference. 



H. Spencer. 



Birmingham and Gloucester 



Railmay Office, Wurcealer. 



