TRANSACTIONS OF SECTION G. 699" 



properly stiffened within. This tube is to be ballasted, so as to make it v>-e]gh. 1 j 

 ton to the foot-rim less than the water displaced, and is to be held down to ^\•ithill 

 35 feet of the lowest water level by two 3-in. chains passed over the tube, and 

 attached to caissons weighing 500 tons each, and sunk a sufficient distance each 

 side of the centre line to give the requisite angle to the four parts of the chain. 



These moorings will occur at every 250 feet along the tube, and will be at such 

 an angle and so rigid that the tide will not affect them. 



The passage of trains through the tube will relieve the chains of part of tht+ 

 strain on them. 



Ventilating shafts to be provided if found necessary, to act as block-signal 

 stations, and to be protected by light-ships moored on either side. 



The shore ends of the tube are to be laid in channels dredged and excavated to 

 receive them, and aftei-wards filled with concrete. 



The ends are to be laid in these channels on the hottest day that can be con- 

 veniently chosen, and angle-iron rings projecting from the tube, and held firm by 

 the concrete, will prevent any movement from the expansion or contraction of the 

 tube. 



The tube to be commenced in the centre, and to be gradually submerged and 

 anchored as the work proceeds. The two ends during construction -will rest ou 

 pontoons, whereon the work of adding to the tube wiU be carried on above water, 

 the tube being flexible enough to allow of this being done. 



The time required for constructing the tube is estimated at three years, and the 

 cost at eight millions sterling. The working expenses would probably not exceed 

 20 per cent, of the gross receipts. Twenty-seven trains a day in each direction, at 

 1/. a train mile, would yield 5 per cent. ; and three times this number of trains- 

 could be worked through the tube in the twenty-four hoiu's. 



6. On Combined Elliptical, Parallel, and Angular Motion. 

 By George Fawcus. 



7. On tJie Sliakespear Safety Lamp. By Colonel Shakespear. 



TUESDAY, AUGUST 31. 

 The following Papers were read : — 



1. On the Loading of Ships. By 1tV. E. Hall. 



2. On the Steering of Ships. By Professor Osborne Eetnqlds, F.E.S. 



I have received an important communication from the Admiralty, upon the- 

 steering qualities and turning powei's of H.M.S. Minotaur and Defence. As the- 

 experiments therein described were made in accordance with the request of the- 

 Committee of the British Association upon the Steering of Ships, and as the results: 

 obtained are very definite and important, I think it desirable that they should be- 

 placed upon record. I therefore append them to this notice. (See Tables, pp. 700- 



Admiralty, S.W., 



19^A September, 1879. 



SlE, 



I am commanded by my Lords Commissioners of the Admiralty to for- 

 ■ward to you, herewith, for your infoimation, with reference to my letter of the 

 30th April, 1877, S. ||||, the accompanying copy of a letter, dated the 31st Julr 



