Skip to content

Chapter II: Book 5: , chap. 2, Page 403—Account of a new compound Microscope for (1)

Text size

objects of Natural History—is the following passage: “We cannot therefore expect any essential improvement in the single microscope, unless from the discovery of some transparent substance, which like the diamond combines a high refractive with a low dispersive power.” From which it seems certain that the Doctor never contemplated the possibility of working upon the substance of the diamond, though he must have been aware of its valuable properties.

[5] There are fourteen different crystalline forms of the diamond, and of this number, from the laws which govern the polarization of light, the octohedron and truncated cube are probably the only ones that will give single vision. It is unfortunately very difficult to procure rough diamonds in this country, so we are compelled to use stones already cut, and to subject them to trial in the way mentioned in the text.

[6] As many amateurs of science might take an interest in the inspection of the peculiar effect these lenses have on transmitted _light_, I shall be happy to exhibit them, as also the perfect lens.

_Analysis of a newly-discovered Spring, at Stanley, near Wakefield_.—By Mr. William West.

Mineral springs, dependent for their characteristic properties on carbonate of soda, appear to have been little noticed by chemists, and to have been still less attended to as curative means; at least in proportion to the multitude of cases in which that substance is administered in various other forms. Indeed the inference to be drawn from the silence respecting the modes of analysis adapted to such waters in our best elementary treatises, is that they have hitherto been very seldom met with. In one district, however, of Yorkshire, carbonate of soda is of frequent occurrence; it is found in the ordinary springs; often, at the same time with substances with which, in artificial solutions, or when concentrated, it, would be considered wholly incompatible; while at other times it is the predominant, or the only remarkable saline constituent. An analysis of a water of this kind, known by the name of the Holbeck Spa, has lately been published in the Annals of Philosophy, by my friend E. S. George; similar springs are found, I understand, as far [p022] westward as Bradford; they are numerous from the borings in and near Holbeck; while eight miles south, a water similar in its character, but differing in containing about twice as much alkali in the same measure, has been discovered at Stanley.

About two miles from Wakefield, near the Aberford or York road, is an ancient mansion called Hatfield Hall; near the park or inclosure of which, in boring for coal, the spring in question suddenly gushed up, when the workmen had got to the depth of eighty yards, and has continued to run spontaneously, in all seasons, at the rate of six gallons per minute.

The water at the spring is limpid and very sparkling; the portion which is allowed to escape, deposits upon the trough and in the channel through which it runs a quantity of sulphur; the smell is that of sulphuretted hydrogen; the taste, from the stimulus of the bubbles of gas modifying the softness of the alkali, rather pleasant than otherwise.

The appearances presented by re-agents are,—

With tincture of soap, a slight opalescence.

Nitrate of silver, an abundant precipitate, partially re-dissolved by pure nitric acid.

Sulphate of silver, a precipitate only partially soluble in nitric or acetic acid.

Muriate of barytes, a slight precipitate.

Lime-water, a precipitate soluble with effervescence in acetic acid.

Oxalate of ammonia, no precipitate.

On boiling, a slight pellicle appeared, soluble in nitric acid.

Carbonate of ammonia, no precipitate, nor any on the subsequent addition of phosphate of soda.

The water restored the colour of litmus paper slightly reddened.

With tincture of galls and ferrocyanate of potash, no change.

With muriate of lime, the water remained unchanged until heated; but when boiled, a copious precipitate took place.

When concentrated by boiling, the water reddened turmeric paper, and effervesced strongly on the addition of an acid.

Nitromuriate of platina produced no precipitate, however concentrated the water might be. [p023]

The results of the previous experiments indicate the presence of

Soda, Lime in small proportion, Muriatic acid, No magnesia, Sulphuric acid, No iron, Carbonic acid, No potash.

A. To ascertain the proportion of sulphuric acid, sixteen ounces by measure, previously saturated by acetic acid, were treated with muriate of barytes; the precipitate, washed and dried, weighed one grain; this indicates, in the imperial gallon, 3.2 grains of sulphuric acid, equivalent to 5.8 sulphate of soda, dry, or 13 grains crystallized.

B. For the muriatic acid; nitrate of silver, added to sixteen ounces of the water boiled, and the alkali previously saturated, gave a precipitate weighing 2.8 grains; reduced to the proportion in the imperial gallon, this amounts to 26.9 grains chloride of silver, equivalent to 11 grains chloride of sodium (muriate of soda.)

C. The crystalline pellicle separated from a pint of sixteen ounces, on boiling, weighed 0.2 grains.

This was carbonate of lime; but in the water the lime would be combined with muriatic acid, forming 0.22; or, in the imperial gallon, 2.1 dry chloride, or 3.75 crystallized muriate of lime.

D. The precipitate formed on boiling with muriate of lime, weighed from the pint, 3.6 grains; from the imperial gallon, 34.6 grains; showing the water to contain in that quantity a carbonated alkali equivalent to 53 grains of dry, or 59.5 crystallized bi-carbonate of soda.

E. Muriate of barytes, added to the water left on evaporating sixteen ounces to two, gave a precipitate weighing 8.2 grains; deducting one grain for sulphate of barytes, as found in experiment A, we have 7.2 carbonate of barytes; this indicates in the gallon 53 grains of dry, and 59.5 of crystallized carbonate of soda, as in the last experiment.

Lastly, a pint of sixteen ounces of the water, evaporated to dryness, furnished in three trials of saline residuum, weighed after short exposure to a dull red heat, six grains, or 57.6 from [p024] the imperial gallon. Now we have seen that this would consist of

5.8 Dry sulphate of soda (exp. A). 11. Chloride of sodium ( — B). 1.9 Carbonate of lime ( — C). ---- 18.7 38.9 ---- 57.6

The remainder, 38.9, having been converted by the heat into proto-carbonate of soda, is equivalent to 54.5 dry, 61 grains crystallized bi-carbonate, agreeing nearly with the quantities found from experiments D and E.

Following, as I do, that doctrine which supposes the bases to be distributed among the acids in a mineral water in the combinations which possess the greatest solubility, we must suppose the lime to be in the state of muriate; we shall then have to diminish the muriate, and increase the carbonate of soda: so that on this view, the saline constituents of an imperial gallon, in the state in which they exist in the water, are,—

Soda in combination with carbonic acid, equivalent to

Bi-carbonate or super-carbonate 56 gr. dry. 62.5 crystallized of soda

Sulphate of soda 5.8 ditto 13 ditto

Muriate of soda (chloride 8.75 ditto 8.75 ditto of sodium)

Muriate of lime 2.1 ditto 3.75 ditto

The gaseous contents of the water consist of variable proportions of carbonic acid, sulphuretted hydrogen, and carburetted hydrogen; the latter gas is continually emitted from the spring, in greater quantity than the water can absorb; and a portion of the other two also escapes from its surface. I have made many experiments on the gas, separated by boiling; but find the results, as I might anticipate, altogether inconclusive and uncertain. In waters containing, as at Harrogate, these gases with muriates or sulphates, boiling may be expected almost wholly to disengage them; but in this case the affinity of the soda in dilute solution, is likely to retain the carbonic [p025] acid, and even to cause a decomposition of the sulphuretted hydrogen, so as to prevent our obtaining, in a gaseous form, the quantity really existing in the water, and imparting to it sensible or medicinal properties.

On the subject of medicinal qualities I am at all times cautious of giving an opinion: but I may observe, first, that as this spring is dissimilar to any of those which have already attained celebrity, so none of them can form a substitute for this; it is not Harrogate, or Cheltenham, or Buxton, or Tunbridge water: the alkaline springs of the West Riding, of which this is by far the strongest, stand as medicinal waters hitherto alone; the active ingredient, the bi-carbonate of soda, being spoken of in chemical works, as “rarely found in mineral waters.”

Secondly, from the known properties of this substance, carbonate of soda, and the frequency of its administration in a long train of arthritic, calculous and dyspeptic complaints, the water must be highly useful as an anti-acid and as a diuretic; and as the advantages which native mineral waters possess over artificial solutions of the substances, in the great degree of dilution, and the impregnation with gases, and still more in the adjuncts of leisure, exercise, pure air, regulated diet and early rising, are of especial consequence in the latter very numerous class of diseases, those called stomach and nervous complaints; we may fairly suppose that such a spring will be found to be a valuable addition to those previously known, applying, as it does, to cases of such frequent occurrence.

_Observations on the State of Naval Construction in this Country_.

It appears that there is at present a tendency to improvement in every branch of science; monopoly in intellect may now be said to be vanishing; and empiricism is obliged to seek dark corners, to escape the light which is penetrating into regions from which it had but very lately been excluded. The administration, too, encourages advance of knowledge; yet notwithstanding these favourable circumstances, there still exists, in [p026] some minds, an inaptitude of scientific perception, which induces unwillingness to acknowledge the advantage that results from the application of the exact sciences to the useful arts.

This neglect of scientific principles is nowhere more manifest than in the affairs of naval architecture, and it is not confined to the Royal Navy, but extends also to our mercantile shipping; and hence it is that our commercial marine is in some respects behind foreign nations, especially the Americans, in the formation of its ships: our merchantmen are, almost without exception, the most unsafe[7] and slowest ships in the world. The ship-owners, therefore, would do well to consider this circumstance, and endeavour to devise means of introducing science into the merchant yards. The establishment of the new university in the metropolis affords an opportunity of doing it at a comparatively small expense, by the foundation of Lectures on the theory of Naval Architecture; and the support even of a separate institution in the vicinity of the merchant yards of this great port, for the education of ship surveyors, would soon be repaid by the improved character of our merchant shipping.

If the science of Naval Architecture depend on certain physico-mathematical laws, as no doubt it does, it is monstrous to imagine for a moment that such laws can be developed by a flight of fancy, or that a man is born with an _intuitive optical_ perception of the lines of least resistance, &c., or, in the jargon of the craniologists, that he has a naval-architectural bump on his skull; yet one would think that such was the case, when we see men, we cannot say philosophers, start up and loudly assert that they are in possession of the secret of construction; and they are believed because their hypotheses are never submitted to the examination of those who are capable of detecting their fallacy.

The Experimental Squadrons have, with a multitude of perplexing results, elicited, it must be confessed, at least an interesting fact, viz. that there has been an establishment seventeen years in this country, in Portsmouth dockyard, for the scientific education of naval architects, for the Royal [p027] Navy.[8] From the plan of education, as laid down by the Commissioners of Naval Revision in 1810, it appears that, to a requisite knowledge of the _practice_ of their profession, the gentlemen composing this body of naval constructors unite a sound and competent one of its _theory_[9].

It can only be from such a source that we can look for the improvement of our men of war, and it is to be regretted that every means should not be taken to avail ourselves of it: but unhappily such is the force of prejudice that, unless some alteration should be adopted in this institution, it will be in vain to expect advantage from it.

The objection urged against this establishment, namely, that the scientific education it gives to its members precludes them from the attainment of a due knowledge of the practical construction of our ships, is so absurd, that none but weak or jealous minds could ever have brought it forward. Shall it be laid down, in the present age, as an axiom, that a profound ignorance of the principles of his art is the one thing essential to the formation of what is generally meant by the term “practical man?” We contend that, having made, _in vain_,[10] a long and most indulgent trial of a system without science, if we may use such an expression, we must extend to one in alliance with it, a like patronage, before we can be allowed to pronounce a fair and legitimate judgment upon its efficiency.

But even in the peculiar path in which the naval architects educated at Portsmouth might be supposed to excel, we do not find that any opportunity is allowed them to come forward, nor shall we see this until some effort is made by the heads of our naval departments, to allow a broad and open competition to take place. It may be urged, that the learned Professor at Portsmouth (Dr. Inman) in himself includes all that can have [p028] possibly been taught or understood in the establishment over which he presides, and that therefore he is the representative of it in the late and present trials for the palm of excellence; but we cannot by any means assent to this: many of the students must have left his tuition seven, eight, and nine years, and must be between thirty and forty years of age; and it would be strange indeed, if during such a period, and in the prime of life and intellect, some of these, if not all, had not cultivated the science after their own bent of mind, and formed original ideas on the subject: we say, therefore, that Dr. Inman’s constructions cannot be called the production of the establishment—they are merely the effort of one man, whose attention it appears is distracted by a multiplicity of occupations, and can only, along with the vessels of Capts. Symonds, Hayes, and Sir R. Seppings, be deemed criterions of the particular views of an individual.

Mysticism and ignorance always accompany each other; and we may reckon that in proportion as the latter disappears from amongst our ship-builders, so will the absurd vagaries of the former recede, and the subject be placed at last on the true principles of philosophical induction, instead of the caprices of imagination. We look forward, therefore, to this new body of naval architects for the expulsion of all quackery from their profession, and for the exposition not only of what we really do know, but also of what we do not know about it: this is the only way to arrive at truth, which should be the sole object of all investigation; but which we are afraid has hitherto been sadly garbled and perverted wherever it has had to do with naval architecture in this country.

But we repeat that we do not see that the nation is at all likely to benefit from the science or exertions of those gentlemen so long as they are placed in situations where a superior education can have no other effect than producing disgust and chagrin in the mind of the possessor; and if the institution at Portsmouth be designed for no better purpose than that of supplying house-carpenters, joiners, and still more inferior trades, with foremen, it had better be abolished. Some would regard it, as at present used, as a gross mockery on the public [p029] at whose expense it is supported; it is certainly a cruel one of those who have been induced, by the fair and brilliant prospects held out to them of support and encouragement, to devote their lives to this branch of the public service.

But to return to the Experimental Squadron: it is with regret that we must conclude, upon a careful consideration, that, although the experiments are carried on with so much vigour and interest, they are evidently founded on imaginative views, and that there cannot exist any thing like legitimate data where so many failures and anomalous results obtain. Who can read the account of the first Experimental Squadron[11], without immediately perceiving that the constructors of the contending vessels, however sanguine each might have been of the success of his particular fancy, met with nothing but the most perplexing results? We see sometimes one and sometimes the other vessel claim the palm of excellence, and finally leaving the subject as much in the dark as ever. This is the natural consequence of the non-application of inductive philosophy to the question before us, and the most important conclusion that can be gathered from the experiment is, that we have begun at the wrong end, and that it is high time to employ analysis instead of synthesis to effect the desired objects: for in the present state of the theory of naval construction in this country, there are yet no data existing to effect with precision and confidence the synthetical composition of a ship.

We cannot refrain here from noticing the paucity of information contained in the reports hitherto made on the first Experimental Squadron. The best one[11] is but little removed from a ship’s log book, and in some respects is inferior to it: it is of such a scanty nature, that we can scarcely inform ourselves on any point, and that only in a _relative_ degree, of the qualities of the vessels composing it: we cannot find out any mention of their _absolute_ velocities on the different points of sailing, which is a most important omission. We are neither informed in what way the observations were conducted, whether they were made simultaneously or not: unless the former, any attempt at comparison must be very doubtful, if not entirely fallacious. Circumstances of wind and the weather may very widely alter in the [p030] course of a short time, and every endeavour at legitimate analogy be destroyed by such variation. We strongly suspect that this is one cause of perplexity; and another prolific one is the vague idea given of the strength of winds by nautical language. Nothing but the determinations of the anemometer should ever be allowed to appear in an account of such experiments. Every circumstance attendant on the quantity and trim of sail, the heeling, the rolling and pitching of the ship, position of the rudder, &c. should be accurately ascertained and _tabulated_; for it is next to an impossibility and a wilful waste of time to attempt to institute comparisons without pursuing a system of tabulated results, which should be kept in the same form on board each ship.

We must also express our regret that the scientific professor at Portsmouth does not appear to have ascertained the position of the centre of gravity of any of his ships, with regard to height, by the simple and easy experiment long known in principle, and described lately with geometrical rigidity in two or three publications by some of his pupils[12]. The knowledge of the position of this point would have placed him so far above his competitors, in so many important particulars, that we are surprised he should have thrown away his advantage, and descended to a level with his less scientific opponents. We are afraid that, here again, imaginative views have stepped in, and taken the sober mathematician from the only path by which excellence can be attained. We are at a loss to conceive how the stabilities of his ships can be said to be ascertained without the knowledge of the position of this point.

Some of the obscurity which pervades this difficult subject may be overcome, as to broad and general principles, by attentively and _coolly_ observing the progress of marine architecture, since the introduction of cannon into naval warfare, and more particularly during the last century and a half. We shall then clearly perceive that the French, who, as early as the beginning of the reign of Louis XIV., employed men of first-rate talent in their naval arsenals, and neglected no opportunity for the [p031] advancement of science in them, increased and kept increasing the dimensions of their ships, more especially the length, the ratio of which to the breadth has been augmented by them from about 3-1/4.1, to 4.1 within the last century. While this principle was acted on, the improvement of their ships was gradual; and by referring to our own progress in the art, in tardy imitation of the practice of the French, we shall likewise conclude that our navy has derived precisely similar advantages from the same causes. Here we have at once two grand but _concurring_ results derived from an experiment, not made on one or half a dozen different vessels, but on the whole navies of the two most powerful maritime states in the world: and if to these we choose to add the result of the practice of the same means on the Spanish and other navies, we might surely be warranted in saying, from this broad but _certain analysis_ of _facts_, that, in relation to the hull, the _general increase of dimensions, with a greater relative length_, is one cause of the improvements that have been made in the sea-going qualities of the ships composing the fleets of the present maritime powers: the question therefore that remains to be decided on in relation to this principle is, whether we have arrived at its utmost practicable limits, or rather, whether we have arrived at the _maximum_ of improvement it is capable of producing.

This brings us again to the experimental squadrons, as far as they are connected with, and illustrative of, our observations; and the first question naturally put forward about them is, whether there be any thing very peculiar in the formation or dimensions of the rival vessels? We suspect that the answer cannot otherwise than disclose, that neither in principle, dimensions, nor in the formation, can they be said to differ very materially from each other, or from ships of the common construction: indeed we perceive in some a retrogression of ideas and a violation of the principle, that the increase of the ratio of the length to the breadth, in conjunction with a general increase of dimensions, has been a predominant cause of improvement. The fact also of so immaterial a difference necessarily includes a system of masting and sails equally confined, and totally inadequate to produce any great superiority of sailing over ships to which they are so nearly equal in principal dimensions. [p032]

After so many years of trial with the present nearly invariable set of principal dimensions, during which period it may be said, that every possible contour of hull has been experimented on with them, we are inclined to think that almost all has been done that could be done under such restrictions, and that some great step must be made in one or other of the principal dimensions themselves, with correspondent alterations in the masting, before we can expect to see a decided and great improvement in the sailing of our ships. The depth is an element which has arrived at its limit from very apparent external causes; but the length and breadth remain to the skilful constructor without any such clogs to his endeavours; and he has only to accommodate their relation to each other in the manner most conducive to velocity, which in our opinion is the very capital object of naval construction, both in ships of war and of commerce. That it is so in the former, no one will, we apprehend, on due reflection deny; but there will be many who will assert that it cannot be obtained, in the latter, without a sacrifice of capacity; which will defeat the object of carrying large cargoes: to this we may reply, that if a vessel with an expense of one quarter the capacity can make _three_ voyages instead of _two_, will not the merchant be still a considerable gainer in capacity, and still more so by a ready return of his capital[13]?

All observations on well-conducted experiments concur in proving that velocity is gained by increasing the length, to a much greater degree in relation to the breadth, than has ever yet been done in ships; and that the increase of the same element contributes to their weathering powers is too obvious to need insisting upon: it is also generally advantageous, when not carried to an extent which would seriously retard the manœuvring of the ship. This limit has not yet by any means been determined; for it must be recollected, that although the additional length increases the resistance to rotation about a vertical axis, yet the power of the sails to give rotation about the same is also increased, although not in so high a ratio. The power of the rudder to produce rotation is also greater in a long ship than in [p033] a short one, not only on account of the greater distance it is from the axis of rotation, but also on account of the greater velocity, and the more direct impulse of the water on it.

The increase of the ratio of the length to the breadth to produce 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.

Not to be unnecessarily minute, we thus also explain the danger of exposure to the morning air in similar situations; the facts, as they relate to the conducting of malaria, being the same, though the meteorological circumstances are somewhat different. Hence, also, we see why the grey mists which hang over wet grounds in the evening in our own climate, are esteemed pernicious; the truth, however, being, that they are perfectly innocent at certain seasons and in certain places—as in the greater part of Scotland, for example, or in those places and at those periods where malaria is not produced. The distinction is valuable, because of the inconvenience of restrictions on this subject, and because to know where the hazard really lies is to reduce those, and also to prevent the infraction of rules by not extending them beyond what is necessary; and thus also by seeing what are the real dangers of what is called night air, we more easily avoid them. Night air is avoided now, under a false philosophy, because it is cold or damp, or for some other vague reason; while the dangers from mere dampness or cold are as nothing compared to those here pointed out; which also occur precisely where they are least feared, namely, in warm summer evenings, after refreshing showers, and so forth. Hence it is that fevers are produced in summer, in rural situations, and especially perhaps amid the most engaging scenery, by evening walks and exposure to what is naturally considered, as it is felt to be, a balmy and refreshing sequel to a hot day. Let this be enjoyed where it can with safety, and as it often may; but such evening walks will not be safe in any of those situations which I need not repeat here; after having detailed them as I have done in the former paper. And lest I should be accused of wishing to excite unnecessary alarm, I consider, on the contrary, that it ought to be diminished by these remarks; because, if we take the whole of [p044] England, there is perhaps not one acre in a hundred thousand where there is danger from night air, or from malaria in any mode; so that to distinguish where that lies, is to have relieved from useless fears all those who may learn to make the distinctions under review.

To pass from what relates to climate and season, and to proceed to the propagation, simply, of malaria, it is almost superfluous to say, that its influence, as to the production of disease, is much regulated by proximity, which implies a state of concentration or accumulation. Hence the danger arising from vicinity; while, as I formerly remarked, where the generating source is small, this becomes necessary to its effect, since dilution may be expected to destroy the power of the poison.

Comments

Log in to leave a comment.

The Quarterly Journal of Science, Literature and the Arts, July-December, 1827Chapter II: Book 5: , chap. 2, Page 403—Account of a new compound Microscope for (1)

0%37 min left in chapter