velocity should not interfere with the increase of breadth necessary
to produce stability or capacity; for both these qualities, varying
as higher powers of the breadth, a very small increase of breadth may
be attended with a considerable increase of length. If we compare
the Caledonia’s (120 guns) dimensions with those of the Royal George
and Queen Charlotte[14], of 1788 and 1789, we shall find, that 13
or 14 times as much length as breadth has been added to the first
rates of our navy. If we refer to the dimensions of the Commerce
de Marseilles, and those of the next preceding three-decker of the
French navy (for instance, the Ville de Paris[15], taken in Lord
Rodney’s action), we shall find that the French naval architects gave
in her 21 times as much increase to the length as to the breadth. If
this could be done with safety in a three-decked ship, with such a
vast top weight, much more could it be carried advantageously into
effect in ships of two decks, and frigates; but we do not find, in
the latter classes of the ships of the French navy, the increase of
length to go beyond six times that of the breadth. If we refer to the
Old Bellerophon, built in 1772, and the New Bellerophon, built in
1819, we shall find an increase of 24 feet in length, to 1.58 feet
increase of breadth; or the former more than 15 times the latter[16].
To those who oppose the objection that a greater length than at
present used would make the manœuvring of a ship too slow, we answer,
that as the Caledonia and the present first rates of our navy,
although from 10 to 15 feet longer than our two-deckers, are found to
be capital ships in this respect, there is a sure ground to believe,
that the addition of 20 feet in length to the present two-deckers
would not render their celerity [p034] of evolution less than that of
the three-decker; and since, from the reduction of weight aloft, the
centre of gravity would be lowered, and the displacement required to
be less, a somewhat smaller breadth might be allowed to a two-decked
ship of 206 feet long, than to one of 196 feet (especially since
the quantity of sail, remaining the same, is lowered by one whole
depth between deck), a smaller midship section would be, _cæteris
paribus_, required; the velocity of this ship might be considerably
increased. Nothing however can be precisely determined on, with such
a complication of circumstances, beyond a general idea. Calculation
and a strict analysis of ships must be resorted to, in order to fill
up the outline of our reasoning.
But for the same reason that we imagine that an addition of 20 or
perhaps 40 feet would not sensibly injure the celerity of manœuvring
of our two-deckers, we should think that the same increase of this
dimension might be tried without much risk to our first rates, with
an increase of breadth not exceeding 1/20th part that is given to the
length.
We repeat that the very capital object of the science of Naval
Construction is _velocity_, and we are decidedly of opinion that
it is attainable in a much higher degree than at present, without
compromising other necessary qualities, for which we have the
concurrence of facts as far as they go.
The Anglo-Americans, in the last war, took every possible advantage
suggested by views similar to those we have been adverting to, in
the construction of their large frigates. They had, it may be said,
to create a martial navy, and they had to oppose it against fearful
odds; but, free from the prejudices and errors so blindly cherished
by their opponents, and which constantly oppose reform by always
declaring the present practice to be the best, they did not retread
the old path, but began at its last step, and boldly advanced on
this principle into all the branches of the art. They built vessels
upon the most enlarged dimensions, and of a superior weight of
metal, and gave an increased ratio of length to the breadth. The
result of such a procedure, justified the confidence of the American
naval architects in only _one_ maxim, founded upon the _scientific_
observation of facts, and may give us a faint idea of what might
be effected by a still more enlarged and mathematical analysis.
[p035] Our frigates were so inferior to theirs in every way, that
they brought nothing but disasters upon us, excepting in the action
between the Shannon and Chesapeake, and one or two others, where,
assured by their previous successes, our gallant opponents threw away
the advantages possessed by their ships, by coming to close quarters
at once, and deciding the contest hand to hand.—Our ships of the line
could never bring these frigates to action, and owing alone to their
extraordinary sailing, did they evade and mock a large British fleet.
We were finally obliged to build 60-gun frigates after their method,
but when it was _too late_ for the exigency of the period; and thus
it has ever been our fate, for want of science in the constructors of
our navy, to follow the steps of our enemies at a humble distance,
and to be only then driven out of the old track by a terrible
experience of its inefficiency.
Nor have the Americans stopped here;—Mr. Huskisson plainly tells us
that “America is, year after year, augmenting its military marine, by
building ships of war of the largest class[17].” According to Capt.
Brenton, they have built a first-rate[18] of 245 feet length on the
gun deck, and 56 feet broad[19], to carry 42-pounders on the lower
deck, and 32-pounders on the other decks.
Our small class of 74-gun ships lately converted into frigates
carrying _fifty_ 32-pounder guns, we are fearful can only produce
disappointment if ever brought against the American frigates (not by
conversion, but by _construction_), which carry _sixty-two_ guns of
the same calibre, and are 180 feet long on the gun deck.
We must not forget also that our active neighbours the French have
now adopted a most formidable description of [p036] frigates, with
curvilinear sterns[20], and many other important improvements. They
mount 60 guns and carronades—viz. 24-pounders on the gun deck, and
36-pounder carronades on the flush deck.—The former calibre is
equivalent very nearly to 26, and the latter to 39 lbs. avoirdupois.
When we reflect on these circumstances, we cannot but feel surprised
that so many frigates of inferior force and dimensions should be
building in our dockyards. In time of emergency they will only bring
on us a repetition of former disasters and deficiency. We contend
that, instead of building ships of only _equal_ force to those of our
rivals, and thus _waiting_ for the developement of _their_ designs
before we can venture on a single step, we should build beyond them
in every respect. It must and ought to be recollected, that peace in
these matters produces a contest of intellect, and those will have
the advantage in it who attack instead of standing on the defensive.
We ought to lead the way, and to be at the head of the maritime
world, not in _number_ alone, but also in the _individual force and
qualities_ of our ships.
Having expatiated on the advantages of an increased ratio of length
to breadth in relation to the hull of a ship, we will just glance
at some of the principal effects it would have upon the masting
and sails; and here again we conceive that Professor Inman has, in
common with many others, relinquished the many good effects resulting
from it, for the inadequate one, of being able to carry a somewhat
greater quantity of sail, which must necessarily be lofty, and which,
(setting aside this detracting circumstance,) as the velocity of a
ship varies only as a _fractional_ power of the surface of canvas
spread, cannot produce the degree of fast sailing to be wished for,
but at an immense and impracticable quantity of sail[21].
A greater proof of the inadequacy of the present system of [p037]
lofty sail cannot be cited than the fact of its not procuring, under
the most favourable circumstances, a rate of sailing rarely exceeding
one-fourth the velocity of the wind.
As the number of masts should be so regulated as to create facility
in managing the canvas, which is well known to be at present hardly
manageable in a gale of wind, on board large ships, from the enormous
size of each individual course and topsail, we should not hesitate,
therefore, to have _four_ vertical masts, as recommended by Bouguer,
instead of three, in ships built in accordance with the principles
we have been discussing. This would, _cæteris paribus_, require
shorter masting and smaller yards, and the sails being much less,
individually, would be more easily managed and not so liable to
accidents.
From what has been said, and the actual experiments now pending, it
is apparent that the theoretic construction of ships is at a very
low ebb in this country; yet a fine opportunity now presents itself,
if we choose to avail ourselves of it, for rescuing the nation from
this generally acknowledged odium. Let a proper use be made of the
corps of Naval Architects we have, somehow or other, at last got, and
let their exertions, under a degree of encouragement equal to that
bestowed on the old ship-builders _in vain_ for so long a period, be
directed towards the improvement of their art. If they fail, they
cannot claim the excuse of having their endeavours repressed; if they
succeed, as no doubt they will, in advancing their profession to
something beyond mere carpentry, we shall be enabled to bid adieu to
the old and _ruinous_ method of blundering, under the reign of which
nothing but disappointment can ever be reasonably expected.
We have seen and do still see the immense advantages derived by our
country from the encouragement of those branches of science connected
with its manufactures and agriculture; and if we wish to keep our
present superiority, we must follow up vigorously this principle in
all its universality. To the cavils of ignorance and bigotry against
such a mode of proceeding we would answer, in the words of one of
the most enlightened members of the present administration, “This
country cannot stand still, whilst others are advancing in science,
in [p038] industry, in every thing which contributes to increase the
power of empires, and to multiply the means of comfort and enjoyment
to civilized man.”[22]
It is to be hoped, therefore, that His Royal Highness the Lord High
Admiral will extend to this most important national institution, the
School of Naval Architecture, the same vigilant and scrutinizing
eye that every other branch of our naval system is at this moment
experiencing from him, and that he will extend to it that fair play
and encouragement which has hitherto been denied to it. As a seaman,
he can fully appreciate and understand how much the bad qualities of
a ship may neutralize the best exertions of the most experienced and
skilful sailor; and, on the contrary, what a degree of confidence
may be insured in naval operations with excellent ships. We feel
persuaded, therefore, that he will not allow others to think for him
in a matter of so much national importance, and thus allow private
ends to interpose to the disadvantage of public views; but that he
will investigate and judge for himself. We would humbly suggest to
His Royal Highness to inquire into the individual acquirements and
productions, both of a _theoretical_ and _practical_ nature, of those
who have been educated in this establishment, and he would soon be
able to decide whether they be fitting or not for the important task
of constructing our ships, and for the confidence and protection
which we think we have shown has hitherto been ill-advisedly withheld
from them. Such a line of conduct would very soon carry our naval
architecture to a pitch of excellence _worthy_ of imitation, and
instead of being indebted to foreigners for models, we should be
able, with just pride, to point to the productions of British science
and intellect in this noble art.
FOOTNOTES:
[7] By referring to Lloyd’s List, it will appear, upon a moderate
average, that _three_ English merchant vessels are lost every _two_
days!
[8] See No. II. of the Naval and Military Magazine, published in
June last.
[9] This will be readily acknowledged by those who will choose
to read the “Papers on Naval Architecture,” and the “Essays and
Gleanings on Naval Architecture,” two periodical works proceeding
from the members of this institution.
[10] See the Third Report of the Commissioners of Naval Revision,
and the Resolutions of the Society for the Improvement of Naval
Architecture, in which the old system of providing ship-builders for
the Royal Navy is condemned in the most unqualified terms.
[11] Vide No. 1 of the Papers on Naval Architecture.
[12] Vide Annals of Philosophy, for November, 1826; No. 1 of the
Papers on Naval Architecture, and No. 11 of the Essays and Gleanings
on Naval Architecture.
[13] Foreign nations, and more particularly the Americans, find
their advantage in having swift merchant ships, and therefore our
assertion is warranted by facts.
[14] Caledonia, length 205 feet, breadth 53.5; Royal George, length
187 feet, breadth 52.33 feet; Queen Charlotte, length 190 feet,
breadth 52.33 feet.
[15] Ville de Paris, length 185.62 feet; breadth 52.7 feet; Commerce
de Marseilles, length 208.33 feet, breadth 54.79 feet.
[16] Old Bellerophon, length 168 feet, breadth 47.33 feet; New
Bellerophon, length 192 feet, breadth 49 feet.
[17] Vide this gentleman’s speech on the Shipping Interests in the
House of Commons, May 1827.
[18] Called by Capt. Brenton the Ohio; but it appears from Lieut.
De Roos’ personal narrative, just published, that the Ohio is a
two-decker of 102 guns. It is to be supposed, therefore, that the
three-decker of 135 guns, called the Pennsylvania by the latter, is
the ship alluded to by the former. It is a matter of great regret
that Lieut. de Roos has not presented us with the precise dimensions
of these ships.
[19] These dimensions carry the ratio of the length to breadth above
4-1/3 to 1.
[20] The French Admiral Willaumez, in his “Dictionnaire de Marine,”
published in 1820, says under the article _Frégate_, that as far
back as 1804, he had proposed a plan for a frigate of the largest
size, with a round stern, wherein the quarter galleries were
suppressed: the first frigate upon his plan was built at Brest about
1821.
[21] As the square root, so that to get _twice_ the velocity, _four_
times as much canvas must be spread; and this is the most favourable
estimate that can be made.
[22] Vide Mr. Huskisson’s speech on the Shipping Interests.
[p039]
_On Malaria_. No. II.
[Communicated by J. Mac Culloch, M. D., F. R. S., &c. &c.]
Having pointed out, in the former paper on this subject, the nature
of the soils or places, of whatever description, by which malaria is
generated, it remains to notice a few other circumstances connected
with its natural history, a knowledge of which is essential for
the purposes of prevention; and finally to describe such modes of
prevention, applicable to these several circumstances, as have
been found useful in guarding against the attack of diseases from
this cause. Under the first head, there remain to be considered,
the effects of climate and season; the changes which occur in the
production and propagation of malaria, from various natural and
artificial causes; and also, the various modes in which it is
propagated.
It has already been remarked, that a certain elevation of temperature
was necessary to the production of this poison, though what the
precise degree is, has not been ascertained; and as this is, chiefly,
what distinguishes the regions or periods of the year which generate
malaria, I need not make two divisions of season and climate. If,
however, this temperature is not fixed, it will perhaps suffice
for our present purposes to say that the greater part of Scotland,
whether as to climate or season, seems incapable of generating the
disease from this cause; though there are exceptions of a permanent
nature, or exceptions of climate, as was perennially true of the
Carse of Gowrie before its drainage; while there are others which
happen when, as in the last year, there has been a peculiarly hot
summer, and which are exceptions of season.
And thus it is as to more northern regions; where a hot summer
becomes more than an equivalent for an average low temperature;
as an example of which, there is no place where intermittents are
more severe and abundant than at Stockholm. But the extreme of evil
from this cause occurs, as is well known, in the tropical climates;
appearing almost proportioned to the heat of the climate, and what is
important to observe to the moisture also. The destructive effects of
certain parts of Africa, India, America, and so forth, are familiarly
known; and [p040] it is in these countries especially, that the
diseases from this source constitute nearly the entire mortality of
the human race. And thus, for Europe, it is in Spain, Italy, and
Greece, and chiefly on their Mediterranean shores, that the activity
of malaria scarcely yields to that of the intertropical climates;
while in France, Holland, Germany, Hungary, and with us, in a far
less degree, the production will be found regulated by the heat of
the summers, all other circumstances being the same.
And if we thus account for the variations in the quantity and
virulence of diseases in any given country, for noted seasons of
epidemic in the countries which I have just named, and for the great
prevalence of fevers among ourselves during the last few years, and
particularly in the last summer, there is another point of scarcely
inferior importance to be taken into the consideration, independently
of that which relates to peculiar winds as connected with the
propagation of this poison;—and this is, moisture.
I need not repeat that water in some form is necessary to the
production of that peculiar vegetable decomposition which is the
source of this poison; and so true is this, that even in the
tropical regions, the diseases from this cause are nearly unknown in
districts of peculiar dryness, as they are in the drier seasons of
those countries. Thus, for example, Egypt is free from such fevers,
except at the period of the subsidence of the Nile, unless where,
as at Damietta, the cultivation of rice is pursued; and the same is
true of Mesopotamia very remarkably: and if I dare not extend these
illustrations, I must remark that in all these cases, the action of
moisture is twofold, inasmuch as it not only accelerates vegetable
decomposition, but renders the atmosphere a fitter conductor of this
poison.
Taking these two causes of the increase in the quantity and in the
action of malaria, we can explain many particulars which relate
to its power in producing diseases: and as the knowledge of these
is important as far as relates to the main object of this paper,
prevention, it becomes necessary to explain them at a little more
length.
As to season, the simplest case is that of the intertropical
climates; and Africa offers the plainest instance among the [p041]
whole. There, the malaria and the fever commence at the moment the
rain falls; diminishing as the ground becomes thoroughly wetted,
and recommencing as it dries. The explanation of all this ought to
be obvious; and the same analogy governs all the hotter climates,
as, though less conspicuously, it does our own. Hence we explain,
both as to our spring and our autumn, the effects of heat following
rain, or the reverse, and the diseases which are consequent on those
changes: and thus it is, though more remarkably, in Italy, that a
rainy autumn increases the number and severity of fevers; or, if the
summer has been unusually dry, that they often do not appear till the
commencement of the autumnal, or even the winter rains. And hence,
also, even with us, the occurrence of a single rainy day or week, in
the midst of the heats, will produce fevers; while the effect of this
influence is such, that should there even be an entire rainy summer,
and the subsequent one be hot and dry, this will be attended by an
unusual production of malaria and disease.
And if I cannot detail all the various modes in which these
circumstances may be modified, and how their effects may vary, it
will be useful to make one remark on an error as relating to it which
is universal among us, and into which even Lind has fallen. The error
is, to think that the rain, the moisture, or the cold is itself the
cause of the diseases which follow this state of things; while it is
obviously a case analogous to that of Africa, if less severe, and the
malaria is produced by these circumstances on soils which I formerly
pointed out, and which Lind, like every one else, had neglected. But
if I must pass over many interesting and useful conclusions to be
drawn from these general principles, there is one fact which I must
notice, and it is this:—
In spring, the combination of heat and moisture, easily explained,
generates, most commonly, intermittents; or the effect of the malaria
at this season differs from what it does in autumn: while as the
heat advances and the ground dries, this kind of fever ceases to be
produced, a new species, or the summer remittent, taking its place
when the heat and the moisture of autumn begin to act. But under
peculiar seasons of heat and moisture with us, it sometimes occurs,
as it has done [p042] within the last years, that the intermittent
season runs into the remittent one, or there is no midsummer interval
of freedom from disease; while it has also happened, and in some
parts of England in this last year, that what would have been
intermittent fever in other years has been remittent; or the common
fever has occupied the whole summer, continuously, even from March to
November, as is the case in the worst regions of southern Europe.
Now, under these exceptions, which I was bound to explain, the
commencement of intermittent, or of vernal ague, may be fixed about
the middle or end of March, and its termination similarly in May;
while that of remittent may be placed in the beginning of August,
and its termination with the middle or end of October. How these
periods may otherwise be affected by the more or less insalubrious
nature of the district or place, will easily be judged of by those
who will reflect for themselves on what I dare not explain, lest I
should infringe too far on my limits. All else that I can venture
on, as to this part of the question in hand, relates to the effects
of the different times of the day on the production, propagation, or
influence of malaria, and it is one which is of no small importance
in a practical view.
Whether the changes as to temperature and moisture which occur within
the space of twenty-four hours, affect the production or propagation
of malaria, I will not here inquire minutely, from the fear of
prolonging this very limited paper; but the general facts, as to its
effects, are these: If we commence with the sun on the meridian,
there appears, even in the worst climates, very little hazard of
fever; while in Italy, it is believed that there is, generally,
little or no hazard, except in some peculiarly pestilential places,
and under particular kinds of inattention or neglect. Either the
malaria is decomposed or destroyed by the heat, or else the air from
its dryness ceases to be a conductor; but as evening approaches,
its influence becomes powerful and dangerous, being supposed most
generally to extend all through the night; while in some parts
of that country it is a popular belief that it terminates before
midnight, or with the precipitation of the atmospheric moisture.
Whether this last opinion is true or not, the general fact explains
the popular [p043] belief, and truth, respecting the poisonous
effects of dew in the hot climates; the supposed pernicious quality
of this depending evidently on the malaria by which its formation is
accompanied. And in this case it is probable that the evil arises,
not from a fresh or peculiar generation of malaria, but from the mere
fact that the moist atmosphere is a better conductor than a dry one.