TRANSACTIONS OF SECTION G. 631 
Section G.—MECHANICAL SCIENCE. 
PRESIDENT OF THE Section—James Brunuens, F.R.S.E., F.G.S., 
Pres. Inst.C.EH. 
[For Mr. Brunlees’ Address see p. 685. | 
THURSDAY, SEPTEMBER 20, 
‘The following Papers were read :— 
1. A Comparison of Morecambe Bay, Barrow-in-Furness, North Lancashire, 
West Cumberland, §c., in 1836 and 1883. By Hype CLarke. 
The writer gave an account of his plans and surveys in 1836 for forming a 
through line of railway from Lancaster, through Furness and West Cumberland, 
across the Solway to Dumfries, and thence to Glasgow, by the course now adopted 
by the Glasgow and South-Western Railway. The chief feature was the passage 
and embankment of the large estuaries called Morecambe Bay. ‘The history of this 
undertaking was given, with details of the plans of Messrs. Hyde Clarke, George 
Stephenson, Hague, Rastrick, &c., and the works carried out by Mr. James Brun- 
lees. The plans of the Warton Land Company were described. The effect of the 
undertaking in the development of Barrow or Foudrey and the iron manufacture 
of Furness was illustrated. 
2. On the use of the term Stability in the Literature of Naval Architecture. 
By Professor Osporne Reynowps, F.B.S. 
The term stability is one which has been adopted by mathematicians, with its 
general meaning unaltered—unrestricted. The mathematical as well as the general 
meaning of stability, is a state of being able to maintain a particular position 
against any force tending to overthrow it, or when, on being disturbed and 
left. free, of being able to return to its original position. It is one of those few 
terms used in a technical as well as a general sense, with the same meaning, and 
this a meaning about which there can be no question. It would appear that stability 
is not a nautical term, that is to say, not an old nautical term, but has been intro- 
duced into the science of naval architecture with mathematics. In nautical lan- 
guage a ship was said to he stiff or crank, according as it offered great or small 
resistance to upsetting forces, while, if a ship would turn over without upsetting 
forces she was called topheavy. 
The calling in the aid of mathematics to give definite expression to these 
various qualities in ships, brought in with it the use of the terms stable and un- 
stable equilibrium. 
And hence came the use of the term stability as implying the margin of stable 
equilibrium. But this was going beyond the mathematical use of the term, for 
stability, as a quantitative measure, has never received mathematical definition 
—there being so many causes of stability which must each be measured in a 
different way. Thus the stability of a large oak tree arises from the strength of 
the trunk, which will resist a very great force, but which, if sufficient force be 
brought to bear, will lose its condition of stability before it has bent to a sensible 
_extent—while, on the other hand, there is the stability of a ship, a reed, or a cradle, 
which, while readily yielding according to the magnitude of the disturping force 
will not lose its power of resistance until a certain degree of disturbance is attained. 
