1867.] Engineering — Civil and Mechanical. 107 



parts of the works special modes of construction must be adopted. 

 The Metropolitan Extension Railway to Brompton and Notting 

 Hill, passes in its course immediately beneath several fine and lofty 

 houses at Pembridge Square. In order to avoid pulling these 

 houses down, they have in the first place been underpinned; 

 trenches were then dug, in which the side walls of the railway 

 tunnel have been built, and wrought-iron girders are now being 

 placed from wall to wall ; the spaces between each girder will be 

 arched over with brick in cement, and upon these the foundations 

 of the houses will ultimately rest. The other principal works in 

 progress in London are the Holborn Valley Improvement, the 

 Thames Embankment, and the Metropolitan Main Drainage. 

 With reference to the latter work, the quantity of sewage to be 

 disposed of on the north and south sides of the Thames amounts to 

 10,000,000 and 4,000,000 cubic feet respectively, and the sewers 

 have been proportioned for an increase up to 11,500,000 c. f., in 

 addition to a rainfall of 28,500,000 c. f. per day on the north side, 

 and up to 5,720,000 c.f., and a rainfall of 17,250,000 c. f. per 

 day on the south side. Altogether there are now in London about 

 1,300 miles of sewers, and 82 miles of main intercepting sewers, 

 and the pumping power amounts to 2,380-horse power nominal, 

 whilst the execution of the main drainage works has involved the 

 excavation of 3,500,000 cubic yards of earth, and the consumption 

 of 880,000 cubic yards of concrete, and 318,000,000 of bricks. 



An improved machine for tunnelling through soft ground has 

 been invented by Mr. R. Morton, of London. It consists of a tube 

 the size of the tunnel, formed of rings of cast iron, in front of which 

 a large wrought-iron wedge-shaped shield is pushed by hydraulic 

 pressure. This shield is made at the back of a similar section to 

 the tube, over which it makes a movable but watertight joint ; the 

 pointed shield having been thrust forward a few feet, another ring 

 of segments is added to the tube inside the shield, and the work 

 goes on as before. 



On the 11th October the inauguration of a graving dock at 

 Suez took place. The dimensions of the dock are sufficient for it to 

 contain ships of the largest tonnage, its length being 492 feet, its 

 breadth 95 feet, and depth, 32 ■ 8 feet. The total cost of the work 

 amounted to 360,000Z. 



Mr. Richardson's experiments in Woolwich Dockyard on the 

 use of petroleum as fuel are likely to lead to very important results. 

 Already we hear that one of the locomotives on the Scinde Railway 

 is about to be fitted with apparatus on this gentleman's plan, and in 

 the event of the experiment proving successful, it is intended to 

 take advantage of the large quantities of petroleum which are pro- 

 curable from Assam. 



One of the four great tubes of the Waterloo and Whitehall 



