January 9, 1915. 
LAND 'AND WATEK 
ways sufficient for the Bervice of the ship, which can be closed 
down whenever it is necessary to use forced draught. This 
means filling the space below the deck with compressed air at 
a pressure of three or four inches' of water, say a couple of 
ounces only to the square inch. 
Now, considering a vessel with a turtle-deck and a big 
hole rent in her bottom (as large as you please), it is clear 
that we have a somewhat distorted case of the old "diving- 
bell," familiar in every textbook of physics for the last cen- 
tury at least, in which the persons in the bell are kept dry 
by pumping in compressed air as the bell descends — tho pres- 
sure of air inside being kept equal to the weight of the head 
of water outside. 
This " diving-bell " idea is in daily use all over the 
world by civil engineers for getting in deep water founda- 
tions, making tunnels under river beds', etc., and this at 
depths far greater than anything required even in our big- 
gest battleship — in which a pressure of one atmosphere only 
would be required to counterbalance the weight of a thirty- 
foot column of water outside. At this depth men feel little, 
if any, discomfort, and can work for fairly long spells. All 
that is required to fit out a cruiser or a battleship in this 
manner is the provision of what are called " pneumatic 
locks " at the hatchways to enable the men to get in and out 
to their duties. 
Now, to the best of my recollection, the rock on which 
Sir William Wliite and I split was briefly this: 
He contended that if a ship was struck by a mine fairly, 
the shock would be so great that tlie vessel would break up 
structurally, and therefore the safeguard I proposed would 
not be worth employing; I maintained that neither the Re- 
sistance nor the Oberon, nor, in fact, any fighting ship of 
which I had ever heard, had been damaged structurally to 
this extent, even by 5001b. charges of gun-cotton, which was 
double the charge usually employed in torpedoes or contact 
mines. So far the experiences of this war and the Japanese 
have proved that I was right on this point, for except when 
the magazine has been exploded, all ships, even merchantmen 
of quite moderate tonnage, have floated quite a reasonable 
time, thus demonstrating that the structural damage has been 
small. 
What I believe is now required is for a committee of in- 
fluential civil engineers and civilian naval architects to take 
up the question, and to extort from the Admiralty a definite 
reasoned statement of such experiments as have been made 
in this direction, and why or in what point they failed. 
There may be somo obscure reason connected with the 
working of the ship to justify the neglect of such experiments 
— but against this I noticed that the Annual Report of the 
U.S. Naval Department a few years ago stated that experi- 
ments with compressed air had given satisfactoi'y results. 
But even if the " pneumatic look " difficulty is really the 
crux of the case, and reconstruction of older types is out of 
the question, there seems no reason why we should not give an 
extra five-feet depth to the double bottom, which is, or can 
be, structurally isolated from the hold of the ship, and then 
keep this permanently full of compressed air. It would be 
equally efiective in keeping out the water. 
At any rate, it seems to me only right that in such an 
important matter the country should be informed in a man- 
ner intelligible to competent civil engineers, who know all 
about the use of compressed air, whether full and conclusive 
exf)eriments have been made, and why they have led to no re- 
sulta. I know that a few years ago a great many naval officers 
fully shared my view of the matter. 
I should like to take tfiia opportunity of acknowledging 
the many valuable letters I have received from readers of this 
paper, and to apologise for my failure to answer all of them — 
pressure of work being my only excuse. I may add that, with 
exceedingly few exceptions, the suggestions these letters con- 
tain are not new, and for the most part are already in the 
Service or about to be adopted, if the campaign lasts long 
enoufjh. 
CORRESPONDENCE. 
TO DESTROY SUBMARINES. 
To the Editor of hhvn and Water. 
Bra, — I have been struck with the many brilliant sug- 
gestions towards helping on the work of the Allies ashore and 
afloat, but I have thought of two other plans which, as an 
armchair critic, seem to me feasible, and which I have not 
yet seen in print : — 
Why not acquire the three or four motor-boats, 
" Maple Leaf," " Despujols I. and II.,' etc., which have done 
over fifty miles an hour? In calm weather, such as the Cux- 
havcn attack enjoyed, tliey would bo invaluable for locating 
and destroying the periscopes of the submarines. As they 
«n]y draw about eighteen iuches of irater, no torpedo could 
touch them. In^epeed no submarine or destroyer could catch 
them, and being such small marks, they would be nearly im- 
possible to hit at the pace at which they could travel. 
Each might have a small quickfirer to destroy periscopes. 
In fact they could easily come alongside and break or destroy 
the latter by pulling an oil drum or something of the kind over 
them. 
Another suggestion occurred to me on reading the 
account some weeks ago of a submarine which got caught in 
a fishing net, and had to come to the surface to get disen- 
tangled. There are miles and miles of old neta in all our fish- 
ing villages, and these could be put outside of the harbour 
to be attacked by our fleet, and on the enemy's submarines 
coming out they would be immediately caught by them and 
would have to come to the surface at a place of which the 
Allies would have already got the range. The nets could 
be sunk to any depth, and would make an almost impene- 
trable wall, as they would effectively stop the propellers of 
the submarines, in which they wquld get twisted up ; and 
anyone who has done any fishing in a propeller-driven boat 
knovra how difficult it is to get even a single fishing line free 
when caught in a propeller. 
I offer these two suggestions for what they are worth. — 
I am, dear sir, yours faithfully, 
Dungarvan Club, co. Waterford. Robebt T. LouaAN. 
A BULLET TO DESTROY ZEPPELINS. 
To the Editor of Land and Water, 
Sir, — Your correspondent, Mr. D. S. Macnair, suggests 
that as it is accepted that the ordinary rifle bullet would be 
useless to destroy Zeppelins, it should be an easy matter " to 
design a hollow bullet containing a charge of some pyro- 
technic composition which would ignite when the rifle is 
fired." 
Permit me to point out that such a bullet has been de- 
signed recently by Mr. Charles E. Dawson, of Uckfield (whom 
I may mention, incidentally, is the discoverer of the famous 
Piltdown ekull). The following de- 
ecription of the bullet and the accom- 
panying design appeared in a recent 
issue of the Sussex County Herald: — 
" An ordinary bullet is bored at 
the apex to form a cavity, which is 
filled with phosphorus and a small 
portion is allowed to project beyond the 
apex of the bullet. On discliarge the 
plwsphorus is heated, and it flames, or 
is predisposed to flame, on coming into 
the slightest contact with another body. 
Thus on coming in contact with an 
airship it would immediately ignite 
the gas, and the machine would be 
destroyed. An ordinary bullet would, 
of cour&e, merely penetrate the en- 
velope without doing further damage. 
" Mr. Dawson's bullets are in- 
tended merely for the destruction of 
airships, and when not in use must 
bo kept under water to preserve the 
phosphorus. The smallness of their 
size is an advantage over the shells, 
which may destroy buildings. The 
bullets' must be used with care and not 
for ordinary uses, as considerable 
damage by fire might be done." — 
Yours faithfully. Arthur Beckett. 
"MORAL" AND "MORALE." 
To the Editor of Land and Water. 
Sin, — With all deference to Mr. Belloo, the reason why 
we spell (or used to spell) " morale " with a final e is not far 
to seek. We borrowed the word from the French in the 
eighteenth century, and in French, as everyone knows, it is 
spelt moral, but we already had the word " moral," which is 
an adjective, and is pronqunced with the stress on the first 
syllable: the word which we borrowed is a substantive, and 
(as we pronounce it) has the stress on the second syllable, so 
we gave it a final «, partly in order to distinguish it from the 
adjective " moral," and partly to indicate the difference in 
pronunciation. The spelling morale was universal from the 
eighteenth century until quite recently, but unfortunately a 
year or two ago some wiseacre discovered that the Frencli 
word is moral, and so now we think we ought to alter a time- 
honoured spelling in order to shew that we know the origin 
of the word. If Mr. Wiseacre is logical, he will suggest that 
we ought to write "sovcrain " instead of "sovereign," and 
" naif " instead of " naive." — Your obedient servant, 
Charles Sweet. 
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