CATALOGUE. PHILOSOPHY AND AUTS, PRACTICAL MECHANICS. 177 



Bunce's plan and elevation of a dome. Loud. 



1792. R. I. 

 Southern on the equilibrium of arches. Ph. 



M. Xr. 97. 

 Note of Bossut's memoir on arches. Ph. M. 



XI. 179. 

 Tatham's bricks for circular arches. Ph. M. 



XV. 143. 

 Mascheroni sull' equilibrio delle volte. 4. 



Bergam. 1785. 

 Montpetit on the theoryof iron bridges. Roz. 



XXXII. 430. 

 Trembley on arches. Roz. XXXIII. 132. 

 Hutton's principles of bridges. R. I. 



Hutton recommends an elliptical arch. 



M. Young on the gothic arch. Ir. tr. 1789. 

 III. 53. 



Kastneron cylindrical vaulting. Commentat. 

 Gott. X. M. 30. 104. 



Prevost Dacier on the iron bridge at Coal- 

 brook Dale. Roz. XXXV. 16. 



Bridges. Smeaton's reports. 



Arches. Langsdorffs hydraulik. pi. 8. 9, 



Burdon's patent cast iron blocks and tubes 

 for arches, with an account of the bridge 

 at Wearmouth. Repert. V. 36l. 

 The arch is a segment of a circle, its span 236 feet, its 



versed sine 31, making about 84°. Its weight is goo tons, 



260 of them are iron. The height from the level of the 



water is 61 feet. 



Plates of the bridge at Wearmouth. R. I. 



Jordan's patent for bridges. Repert. VI. 220. 



A path suspended from an arch. 



Nash's patent bridges, of hollow iron and 



earth. Repert. VI. 36 1. 

 Wyatt's bridges without wood. Repert. XIV. 



145. 



Hollow pieces of cast iron. 

 Robison. Enc. Br. Suppl. Art. Arch. 

 Atwood on arches, with a supplement. 4. 



1801. R.I. 



VOL. II. 



Review of Atwood, said to be by Robison. 

 British critic. XXIII. 6. 



Person's pumps to be used in building 

 bridges. Recueil, pi. 4. 



Iron bridges. Fulton on canals. 



Tatham's circular architecture. 8. Lond. 

 1803. R. I. 



Tatham's patent clumps. Ph. M. XV. 143. 

 Repert. ii. II. 3^3. 



Wilson's patent for uniting iron blocks. Re- 

 pert. ii. III. 87. 



Rees's cyclopaedia. Art. Arch. 



New bridge at Paris. B. Soc. Phil. n. 78. 



Reports on the port of London, f. R. I. 



Supposing the pressure of the materials vertical only, a 

 quadrant of a circle will support a horizontal road in equili- 

 brium, if the depth of the bridge in the middle be to the 

 radius as 1 to 61, that is, about onfe ninth of the span. 

 Emeis. Mech. But this appears to be only an approxima- 

 tion. 



A catenaria will support a horizontal road lOo feet above 

 it, if the height and half the span are each 159. A loga- 

 rithmic curve will form a half arch of equilibrium if the 

 road be horizontal. Emerson. But all these proportions 

 would make the bridge too heavy. 



Perronet thinks that a bridge of 500 feet span might 

 stand, the bridge of Mantes having sunk to a radius of soo 

 feet. 



In the construction of bridges. Professor Robison obsenres, 

 th^t something is to be allowed for the lateral pressure of 

 the materials ; and that the cohesive strength of the arch, 

 and its resistance to any force in the manner of a lever, 

 ought to be taken into the calculation. These remarks are 

 extremely just, but they do not appear to have been practi- 

 cally considered, except so far as theory has been modified 

 by experience. 



If there be an arch composed of stones of a given magni- 

 tude considered as perfectly solid, the effect of a weight 

 bearing on the key stone will be a displacement of the 

 pressure ou the abutment : the centre of pressure on the 

 abutment will be removed to a distance, which is to the 

 height of the arch nearly as the tangent of the immediate 

 change ot the direction of the new compound thrust of the 

 key stone to the radius. It seems to be desirable that this 

 A a 



