632 REPORT—1883. 
All these objects may be strictly said to possess stability, but if we use the term 
stability in a quantitative sense to express these qualities, in the one case it must 
mean a quantity of force, and in the other a quantity of space or angular 
disturbance. 
This difficulty in the quantitative use of the term stability appears to have been 
lost sight of by naval architects, who used the term to express both the extent of 
heel which a ship might safely suffer, and also the upsetting force necessary to cause 
this heel. This confusion has not passed without remonstrance, but it appears 
from the report of Sir E. J. Reed on the ‘Daphne’ disaster, and the discussion to 
which it has led, that naval architects are using the term stability both in its 
proper sense, as meaning a tendency on the part of a ship to hold a particular 
position, and also as meaning a tendency in a ship to change its position in a 
particular direction. Thus, in laying down the rule which he intends to controvert, 
Sir E. J. Reed expresses it thus. ‘If a ship has initial stability, and has some 
stability also at very large angles of inclination, say 90°, then it is quite certain 
she will possess some stability at all intermediate angles.’ The strict meaning of 
such a rule would be that if a ship when slightly disturbed from its vertical posi- 
tion would return to that position, and also if, when slightly disturbed from the 
position of lying on its beam ends, would return to this (beam ends) position, then 
when slightly disturbed from a position of any particular angle of heel, it 
would return to that particular angle of heel. As thus interpreted the rule is 
obviously absurd; and it is clear from the context that in the two phrases 
‘initial stability’ and stability at 90°, the term stability has been used in two 
contradictory senses. In the first phrase it clearly has its right meaning, namely 
that if the ship be somewhat disturbed from the vertical position it will return, 
but what does it mean in the second phrase—stability at 90°. The only interpreta- 
tion which will make the rule sense and be consistent with the meaning of stability, 
is that by stability at 90° is meant that for a disturbance of 90° the ship will still 
be stable about its vertical position. In this sense the rule is intelligible, and 
necessarily true, and by no means contradictory to anything urged in the report, 
but this is not the sense in which it is clear by the context Sir E. J. Reed under- 
stands it. He clearly interprets stability at 90° to mean a tendency to return from 
that position towards (not to) the vertical, And this interpretation I wish to point 
out is inconsistent with the strict meaning of the term stability. 
It has been long ago pointed out that in order to express the statical qualities 
of the stability of a ship in definite language, it was necessary to use two terms, 
the one to express the greatest angle of disturbance from which she would return 
to her normal position, and it was proposed to limit the quantitative meaning of the 
term stability to the measure of this angle, using the term stiffness to express the 
moment of the upsetting forces necessary to produce any particular angle of dis- 
turbance. 
The adoption of this system, which is consistent and definitive, would prevent 
the confusion into which it appears naval architects have fallen. It would then 
be seen that what are ill called curves of stability would be well called curves of 
stiffness. The importance -of this at once appears on applying these curves to 
determine the sailing qualities of ships—for, supposing the upsetting force of the 
wind constant, the true stability of the ship, with a given wind and spread of sail, 
is determined, not by the stiffness, but by whether the stiffness at the particular 
angle of heel is less than for greater angles. And thus the stability, in a quantitative 
sense, i.e. the safe angle of heel under wind pressure is limited, not by the heel at 
which stiffness vanishes, but by the heel at which it becomes a maximum. 
3. On the Euphrates Valley Railway. By J. B. Yuu. 
Two ports as points of departure on the Mediterranean were examined by 
General Chesney and Sir John Macneil, one being Seleucia, the port of Antioch, 
and the other Alexandretta, in the Bay of Scanderoon; the latter being considered 
to be the best, as the least expensive to construct, and from its being in a fine 
