€88 REPORT— 1880. 



Section G.— MECHANICAL SCIENCE. 

 President of the Section— James Abeenethy, V.P.Inst. C.E., F.E.S.E. 



THURSDAY, AUGUST 26. 

 The Section did not meet. 



FRIDAY, AUGUST 27. 



The Presibent delivered the following Address : — 



As time will not permit of a generally detailed description, I propose, in the 

 Address which I have the honour and pleasure to make as President of your Section, 

 to describe generally the past and present condition of the port of Swansea, as typical 

 of the rise and progress of the various ports in the Bristol Channel within the last 

 half-century, and the vast improvements which have been effected in the nature and 

 extent of the accommodation pro'V'ided to meet the requirements of the shipping of 

 the present day as regards dock facilities and appliances for the rapid and economi- 

 cal loading and discharging of their cargoes rendered necessary by the amount of 

 active competition in every branch of commerce, both export and import. 



I propose to confine myself in this address generally to the engineering history 

 of Swansea Harbour, but I think it necessary, in the first place, briefly to describe 

 certain features of the Bristol Channel, resulting in the peculiar advantages its 

 harbours possess over those of the eastern coast, due to the greater tidal range. 



At its entrance between St. Govan's Head on the north and Plartland Point on 

 the south, its width is 42 miles, gradually contracting, until at King Road at the 

 mouth of the Eiver Avon, 92 miles distant, its width is only 4i miles, the residt 

 being a proportionate ele^■ation of the tidal wave in its progress upward, so that in 

 Swansea Bay spring tides rise 28 feet, at Cardiff 35 feet, and at Avonmouth 40 

 feet, and in consequence engineers have been enabled to provide for the entrance of 

 the largest class of shipping by proAddiug at the various docks recently constructed 

 a greater depth of water than is generally practicable on the eastern coast. The 

 cill of the dock at present in process of construction at Swansea will have a depth 

 over it at spring tides of 32 feet, while the existing cill of the Roath Dock at 

 'Cardiff has 35 feet 8^ inches over it ; that of the Alexandra Dock at Newport 35 

 feet, and the Avonmouth Dock 39 feet — greater depths than exist over the lock cills 

 of any of the ports on the eastern coast generally. 



It would extend my address to an unnecessary length to describe the vast im- 

 provements which have taken place at all the ports in the Bristol Channel within 

 the past half-century. The port of Swansea may fairly be taken as a type, inas- 

 much as from its position it has natiu-al difficulties to contend with, requiring, as 

 At Cardiff, extensive works seaward in order to provide the reqiusite depth of 

 water, such works not being necessary in the case of the docks at Newport, Avon- 

 mouth, or Portishead. 



As regards its situation, the port is placed nearly in the centre of Swansea Bay, 



