15 



gallons, this scheme being from three to five times as costly as Mr. 

 W. Webster's. 



Time warns me that I must not trespass much longer on your atten- 

 tion, but before concluding, I should like briefly to mention one o*" 

 the greatest engineering works of modern times, namely the Forth 

 Bridge, which has been in progress for the last seven years, and 

 which is now virtually complete. The sea, which is liere over a 

 mile in width, has been bridj^ed over — the actual length of the 

 bridge being 8,29G feet, or nearly a mile and five eighths. It com- 

 prises 15 girders of 168 feet each in length, which are simply fhe 

 approaches to the main viaduct, which crosses the intervening 

 space of nearly a mile by four spans, namely two of 1710 feet each 

 and two of 680 feet each. The largest span of any bridge in this 

 country, viz., the Britannia, is little more than a quarter the length 

 of the vast spans of the new Forth Bridge. The towers on which 

 the shore ends of the spans rest are themselves a stupendous 

 engineering work, meaning 360 feet high — than which, only the 

 Eiffel ToAver, Culogne Cathedral, and the great Pyramid are higl^er 

 structured works. The tensible strength of this brijlge is estimated 

 at from 30 to 37 tons to the square inch, whilst the utmost strain 

 likely to be put upon it, either by wind or weight, is barely one- 

 fifth of that amount. The bridge has besn most satisfactorily 

 tested by massing upon the two main spans fifty loaded coal 

 waggons and three of the heaviest engines and tenders, the total 

 weight being over 1,800 tons, more than double the bridge will 

 ever be called upon in future to bear. The deflections were in 

 exact accordance with the calculations of the joint engineers. Sir 

 John Fowler and Mr. Baker, 



Some idea of the vastness of this triumph of engineeing skill 

 may be gathered fiom the following statistics. The foundations 

 and piers contain about 130,000 cubic of granite, concrete, and 

 rubble masonry, while the bridge itself consists of 53,000 tons of 

 steel. Eight million rivets hold the fabric tognther — the surface 

 to be painted is equal to twenty acres. Between three and four 

 thousand men have been employed on this gigantic task for the 

 last seven years, and the total cost will be two and a-half million 

 sterling, which sum is to be defrayed by four raihvay companies, 

 who are uniting in this enterprise (or tlieir mutual convenience. 



The successful acchievemcnt of this grand work inspires us with 

 confidence for the future. The scheme of a bridge across the 

 channel is now occupying many minds, and in the light of what 

 has just been done, it seems presumptuous to affirm that such a 

 thing is impossible. Time alone can settle this vexed question — it 

 may be that ere many years are passed, the scheme of to-daj will 

 have become an accomplished fact, and we shall then perhaps, 



