xliv. ABSTRACT OF PROCEEDINGS. 



sion in the arch rib. In either case, if the rib is loaded in 

 any way whatever, the correct form, in order that it may 

 sustain the load without bending, is the equilibrium curve 

 or polygon for the loading in question. A large and com- 

 prehensive series of slides were shown illustrating the con- 

 struction of various types of arch and suspension bridges, 

 some of which are as beautiful architecturally as they are 

 sound in construction, as for instance, many of the bridges 

 over the Seine in Paris. The defects in Robling's system 

 were briefly explained, and also the theory of the modern 

 stiffened suspension bridge, consisting of steel cables and 

 steel stiffening girders. As an example of the principle of 

 the cantilever bridge a slide was shown in which the Forth 

 Bridge was compared with two men supporting a third in 

 a special manner. A few examples were shown of mov- 

 able bridges worked by hand, steam, hydraulic and electrical 

 power. In conclusion the lecturer stated that the art of 

 the bridge builder is well illustrated by the various designs 

 which have been submitted for the proposed Sydney Har- 

 bour Bridge. The conditions laid down by the Advisory 

 Board were briefly explained, five of the best designs were 

 thrown upon the screen, and the special merits and 

 features of each were critically discussed. 



CONVERSAZIONE. 



A Conversazione was held in the Great Hall of the 

 University, on Friday, 5th December, at 8*30 p.m., under 

 the management of a Committee composed of the Officers 

 and Council of the Society. The Hall and approaches were 

 tastefully decorated with ferns, palms, and rare pot plants. 



The University grounds were illuminated with electric 

 light thus lighting the way for the guests to visit the 

 various Laboratories which were thrown open. The guests 

 numbered about 450. Unfortunately His Excellency the 

 State Governor was absent from town, but His Excellency 



