420 EEPORT— 1882. 



Before referring in detail to the history of the undertaking and to the 

 character of the design, the author would like to convey, if possible, 

 some notion of the magnitude of the proposed bridge across the Firth of 

 Forth. In preparing the detailed designs he has often experienced no 

 little difficulty in realising the scale upon which he was working. For 

 example, the bed-plates for an ordinary railway girder bridge, say a couple 

 of hundred feet span, would be about half the size of an ordinary dining- 

 table, and it is difScult at first to picture to oneself a bed-plate abont 

 double the size of an ordinary dining-?-oo))i ; but that is the size of the 

 bed-plates for the Forth Bridge girders. A diagram hanging on the 

 wall showed the comparative sizes of some of the largest girder and 

 arched bridges in the world ; but even this failed, in the author's opinion, 

 to impress upon the mind the vast diflference in scale between the pro- 

 posed and all previous bridges. On glancing through the last volume of 

 ' Reports of the British Association,' with a view to obtain a notion 

 as to the ordinary length of papers for Section Gr, he incidentally obtained 

 a notion also for illustrating, in popular but perfectly accurate terms, the 

 size of the Forth Bridge as compared with the largest bridges in this 

 country. In the Report of the Anthropometric Committee it was stated 

 that the average stature of a new-born infant is 19 3i inches, whilst the 

 average height of the Guardsmen sent out to Egypt has been officially 

 given at 5 feet I0| inches. These figures have a ratio of I to 3"65, and, 

 singularly enough, as the largest railway bridge in this country, the Bri- 

 tannia Bridge, has a span of 4G5 feet, and the Forth Bridge a span of 

 1,700 feet, the ratio there also is 1 to 3'65. Hence, to enable anyone to 

 appreciate the size of the Forth Bridge, we have merely to suggest the 

 following simple Rule of Three sum : — As a Grenadier Guardsman is to a 

 new-born infant, so is the Forth Bridge to the largest railway bridge yet 

 built in this country. Bridges a few feet larger in span than the Bri- 

 tannia have been built elsewhere, but they are baby bridges after all. 



Such being the size of the structure, the question naturally occurs, 

 why it should be necessary or expedient to build so unpi'ecedented a work 

 far north in this little island of Great Britain, when it has been found 

 practicable to cover the globe with railways, and to carrj^ roads across 

 the greatest Continental rivers, without involving any such difficult 

 undertaking. The answer is a somewhat complex one. It is not the 

 physical features of the country, but the habits of the population that ren- 

 der the construction of a 1,700-feet span expedient. If the British public 

 can save a few minutes by going a particular roate, by that route will 

 they go, although the alternative one might be as eligible, or even more 

 so, in every other respect. This fact was forced upon the attention of 

 the North British Railway Company nearly twenty years ago, when they 

 sought powers to construct a bridge across the Forth, to secure for them- 

 selves and their allies the Great Northern, North Eastern, and Midland 

 Railways, a fair share of the through ti-affic between England and the 

 north of Scotland, which they alleged had been hitherto practically mono- 

 polised by the London and North Western and the Caledonian Railways, 

 whose route was a few miles shorter. Parliament, satisfied, no doubt, 

 that the contention was a reasonable one, granted the solicited powers 

 in the year 1865. The bridge then proposed crossed the Forth at a dif- 

 ferent spot to the present bridge, as the engineer had not the courage to 

 face a span of 1,700 feet, and nothing less is practicable at Queensf'erry. 

 Owing to the treacherous character of the foundations, however, it became 



