ciple, and published a mode of operation, with respect to which-adverting not to intermediate, because they are less directly applicable publications-six years ago I wrote a paper, the following four paragraphs of which, I must request you to do me the favour of reading :

But it is not on land only that an icing apparatus would be advantageous. Since as ice could be made at sea as well as on shore, (a capability which, by the way, will, eventually, prove important to our fisheries)* while an icing apparatus large enough to ice wines, lemonades, or other beverages for the passengers of any packet, or Indiaman; or wines, &c. for the officers, and grog for the crew of any man of war, could be supplied for a moderate sum, not only might voyages be, in consequence, made sources of profit, but also might passengers and officers partake the luxury, and the whole crews of our men of war in hot climates receive the strengthening and invigorating benefit of having their grog, (and all other beverages, including the very water they drink) iced; a circumstance which would be important, not only medically speaking, and as an auxiliary to the surgeon's care in many cases of tropical fever, but (in degree) even nationally speaking; from the way in which it would strengthen the men, and add to their physical powers, in cases where extreme heat half incapacitates them for bodily exertion; as well as from the degree to which it would serve as a febrifuge under attacks of disease.

There are, indeed, occasions, on which it is possible that this method of counteracting the weakness which torrid zone temperatures produce on our sailors, might prove auxiliary, even to the honour of our flag.

Lord Rodney's victory; that of the Nile; the hard-fought action of Algiers; and others of our glorious naval triumphs, have been gained in hot climates. Now could our sailors, on those occasions for extraordinary exertion, have had part of that native vigour of which the heat of the climate deprived them restored, in consequence of the water which they are allowed to drink during action being, not actually iced (because that might be too cold for men who are excessively heated to drink hearty and hasty draughts of), but made so refreshingly cold as to "smack" on the palate, and invigorate the frame, there can be no doubt that their bodies would have been capable of going through harder work, and their spirits equally disposed to work harder.

Especially to our Newfoundland cod fisheriesas those fish could be brought to us in their fresh state, for less than it costs to split, salt, barrel, and get them hither, in the state we now receive them.

And as this invigorating refreshment could easily be given, by icing a number of butts of water during the chase, to be mixed with the other sickeningly warm water, and served out during the action, it would be equally in a captain's power thus to strengthen the bodies and heighten the spirits of his men, as it is to order an extra glass of grog to be served out, on those occasions when harder duty renders it necessary.

Two years ago, I wrote the following paragraph:

:

Seventhly. The ship, instead of being hot as steam vessels are, shall be "cool as a cucumber;" while she should possess the advantage of being, throughout all tropical regions, capable of supplying ice, not only to cool beverages, but also to cool cabins and berths; so as, in degree, to carry the climate of the temperate zones into, and throughout the torrid zone: a capability which will prove not only a luxury to passengers, but so important a medicinal restorative to the crews of men of war in many cases of tropical disease, as might prevent unmannings of blockading fleets such as, after carrying off 3000 of his ships' crews, broke Admiral Hosier's heart. Indeed, it would require but a small portion of the engine's power and a cooling apparatus, to maintain an atmosphere low as that of the temperate zones throughout the ship; even were she stationed in the torrid zone.

As I placed the brochure out of which I have cut the last paragraph, in the hands of not a few persons two years ago; as I had largely distributed the paper from which the preceding four printed paragraphs are taken, during those six years; and as other observations which I am guilty of, involving the principle, have been before the public for twenty years, I presumed, until the appearance of the Parliamentary paper "179-V" of the present Session, that means would be taken to supply the crews of the ships which are to compose the expedition that you are appointed to command, with a cooled and dried medium of respiration, instead of leaving them to breathe the atmosphere of the Niger, in its naturally hot and humid

state.

But as that paper made evident that though 6007. were to be expended in merely forcing air in its natural condition into different parts of the ships, even the idea of making that air cooler or drier than the hot and humid, atmosphere of the Niger affords, had not been entertained, I became desirous to submit to Mr. Buxton-as the individual whom public opinion considered to be the originator of the expedition-that it is in our power to furnish vessels on the Niger with means of supplying themselves with 10,000, 15,000 or 20,000 gallons of air per mi

nute, cooled from the high natural temperature of those latitudes, to 50° or 60°; and so far desiccated as to deprive it of that excess of moisture with which the air of Western Africa is loaded; and thereby make it as cool and dry as may be desirable for the preservation of health and life.

But Mr. Buxton's absence on the Continent interposed obstacles which prevented me from obtaining his attention until now; when his recommendation makes it a duty to submit to you, that I believe it can be shown that ships in any part of the torrid zone may be kept as cool as the holds of the American ice vessels on the equator; their "between decks" being supplied with ten or twenty thousand gallons of air per minute, cooled and dried as above mentioned; and their crews with whatever quantity (suppose two gallons per man per diem) of iced beverages, the heat of the climate may dispose them to drink.

Could carte blanche be given with respect to time for preparing, and room on board for fixing the apparatus for these purposes, I would not hesitate to commit myself in regard to its efficiency. But considering circumstances which have offered themselves to my reflection since my letter to Mr. Buxton, I submit as follows with reference to time, space, and expense.

Should the same ratio of mortality take place with respect to your crews, as obtained on board the Quorra and Alburkah during Mr. Laird's attempt to explore the Niger, 129 of the 155 Englishmen you take out will be carried off by the climate; without reference to the smaller (though still great) mortality which prevailed among Kroomen on board those vessels.*

the

Whether the public would consider any expense (that was not enormous) which might prevent this, to be objectionable, it is not for me to suppose. But as you will, probably, have to remain on the Niger (or its tributaries) throughout one, if not more wet seasons, and as, without a preventive, there is too much reason to fear that many of your men will, in consequence, fall victims to the climate, it may, perhaps, be permitted me to ask, whether space could be devoted to any better purpose than to containing such means of prevention; and whether expedition which denied time for their application, might not prove to be making more haste than good speed, with respect not only to loss of life, but, possibly, to that of the object of the expedition, from a cause other

than that which may arise from want of "hands."

The idea may prove as erroneous, as its enunciation will be presumptuous: but I feel it, nevertheless, incumbent on me to submit, that you may perceive it natural to one who believes that a cool, and dry atmosphere can be insured on board your vessels throughout the wet season; and who sees no insuperable impediment to your crews being provided with dry exercising space during that period, by your decks being sheltered from the torrents of rain by a tarred sailcloth or caoutchoucked canvass roof, capable of quickly rolling itself up, so as not to be blown away by hurricanes-you may perceive it natural that one who sees nothing insuperable in these things, should also be struck by the idea that, supposing the extent of the inundation in the lower parts of the country did not prevent the channel of the river from being discovered and kept, and also supposing that there should not be other insuperable obstacles which his ignorance renders him not aware of, the vastly greater depth of water during the wet season would allow you to pass rapidly over shoals where the Quorra and Alburkah were detained for, if I remember right, weeks at a time; and enable you to ascend, no one can tell how much higher.

Submitting myself to your censure by venturing to enunciate this idea, I conclude the prolix statement which Mr. Buxton's letter has caused me to intrude on you.

I have the honour to be, Sir,

Your most obedient servant,
JOHN VALLANCE.

AMERICAN MARINE STEAM-ENGINE
BUILDING.

The New York Herald publishes the following letter in reply to our strictures on the construction of the Kamtschatka steam frigate (vol. xxxvi. p. 222,) built at New York for the Russian government, with a recommendatory introduction of it by the Editor to the attention of his "commercial and scientific readers." To the Editor of the "New York Herald."

In a recent number of your paper I noticed an extract from the London Mechanics' Magazine, relating to the steam ship Kamtschatka, which was built for the Russian government, by the Messrs. Schuylers of this city, with an implied invitation to the engineers of this county, to vindicate their reputation from the disgrace which the reputed failure of that ship was likely to bring upon them in that country and elsewhere.

Now, I believe, there are few who were acquainted with the circumstances under which the Kamtschatka was constructed, will attribute her faults to the want of skill or knowledge of American engineers generally. There are few indeed who were ignorant of the fact that, so far as the engines and boilers were concerned, it was professedly an experiment, and that it would not succeed was almost universally believed among practical engineers. The engines, no doubt, were inconvenient and ponderous, and the boilers inefficient and complicated-and suppose they were so, if the Emperor Nicholas desired it, and was willing to pay Jonathan for the labour, who is to find fault? Surely John Bull need not. He may wish to make a little capital out of its unsuccessful issue for the benefit of British trade. It does not look well in his eye, to see other than British steamers splashing in the big pond, even though they do so by the way of experiment! No, it is decidedly anti-British and dangerous in its tendency. It is, no doubt, something else which excites the rabidity of John Bull upon the subject of American ship building and steam navigation. It is not the failure of an experiment, but a kind of fearful consciousness that the resources of America and the developement of American skill will not become tributary to British vanity and wealth. The truth is, there is some evidence of the ability of Americans to compete with the best foreign builders and engineers, if not to establish their superiority over them.

We submit the following extract of a letter to a house in this city, in relation to vessels built in this city, for a foreign government, a short time previous to the completion of the Kamtschatka. Let the practical good sense of American workmen be displayed, free from the restraints and control of theoretical schemers, and the mist will be dispelled which now too much obscures the practical worth of American builders.

An important fact we might mention, in regard to British and American steamers is, that the Sirius, the only foreign steam-ship of about the same tonnage, which has resisted (revisited?) our shores, did not perform, within twenty-five per cent. of the distance per twenty-four hours, which was accomplished by the Regent; while the relative nominal power was as 320 horses to 140a fact that can only be accounted for from the intrinsic superiority of the American engine.

run of three days; the Natchez has been quite successful on this route-Captain S. is an able and attentive commander; few men could at this time take his place in the confidence of the travelling public.

I was much pleased on my arrival with the appearance of the two New York built steamers lying at anchor in this harbour, and as I had never seen them before, determined to take the earliest opportunity of visiting them, and confess my national vanity was somewhat excited by the enthusiastic encomiums bestowed upon the skill and integrity of our countrymen by Commodore De Llanes and the commanders of the ships, which are now called the Regent and Congress. All speak in the highest terms of the performance of the machinery, and those persons who have seen the British and Spanish steamers here allow that the premium must be awarded to the latter by a great majority, and the officers of the British steamers say they are not to be beat; for cleanliness they are unsurpassed. The engines have gained much credit and are highly esteemed; to Mr. Vandewater, 1st engineer of the Regent, I am indebted for a copy of the log of that ship on her recent passage from Cuba, which is subjoined; it will be of some use to those who feel an interest in commercial matters; the appended remarks are his. [The Log referred to is given on our next page.]

We are glad to learn from the preceding extract, that so far as concerns the construction of the engines of the Kamtschatka - which includes every thing material said by us on the subject --the Americans themselves admit that our strictures were perfectly just; "the engines no doubt were inconvenient and ponderous, and the boiler inefficient and complicated." Now that these rather serious defects have been pointed out on this side of the "big pond," all the world on the other side sees and confesses them! Nay, they would even have us to believe, that nothing else than failure was ever anticipated by "the majority" of their "practical engineers." If this be true, we can only say it is rather surprising that none of the said majority ever took any means to make his misgivings public. At the time of the departure of the Kamtschatka for Europe, nothing was to be met with in the American papers on the subject of this vessel but the most extravagant encomiums on her construction and equipment in every particular. We are further told that she was "professedly an ex

whom it would grieve them less to be eclipsed, than their Transatlantic brethren, for whom at all times they have evinced only the most respectful and friendly feelings.

With respect to the vessels (the Regent and Congress) built for the Spanish government, we have already (see our last vol., p. 417,) done justice to their merits, (with quite as much readiness too, as we found fault with the Kamtschatka, and with a great deal more pleasure,) and we are happy to find our anticipations of the performance of their engines, so strongly confirmed, as they are by the log of the Regent, now supplied by our American contemporary. The names of the makers of these engines are not mentioned by their own countryman, but delighting to honour all to whom honour is due, we think it right to repeat here that they were manufactured by Messrs. Ward, Stillman, and Co., of New York; from whom they lead us to expect things still more on a par with the productions of our English workshops. A few such matter-of-fact affairs as the log we now publish, will do more for the credit of American engineering, than whole volumes of such gasconading ribaldry, as the epistolary Jonathanisms by which it is here accompanied.

THE SILLOMETER, DERIVOMETER, SUBMARINE THERMOMETER, AND STEAMENGINE INDICATOR, OF M. CLEMENT.

1. The Sillometer is the title given to a substitute for the common log, which has been recently invented by a M. Clement, of Rochfort, and is so well thought of by the French Admiralty, that it has been ordered to be forthwith supplied to the different ships of the Royal Navy of France. It is a most ingeniously constructed instrument, and promises to be of great practical utility. To describe it as well as we can in words:

A hollow copper ball, against which the water acts, is attached to a moveable plug of the same metal, which slides in a copper tube that passes through the centre of the vessel to the keel; to this plug is attached a lever, which, by means of a vertical rod, acts on a second lever placed on the deck of the vessel, and communicating with a spring; the tension of the spring constitutes an equilibrium with the pressure of the water on the ball, and serves to measure the rate at which the ship is moving, by means

of a hand, the movements of which on a graduated dial, indicate, at every moment, not only the speed of the ship, but also the distance run in any given time. A table annexed to the instrument allows the officer of the watch to note the distance traversed at the moment when he is relieved from his watch. The Sillometer resolves many problems of great importance. It gives every moment the rate of the ship's sailing, and also the space traversed in any given time. It indicates positively either the influence of a sail furled or unfurled, of a change in the placing of the ballast or of the guns, and what is the most favourable direction of the wind for its action on the sails, a matter of great importance, whether in giving or receiving chase. It offers, also, the advantage of measuring, when at anchor, the force of currents on the keel.

2. Another invention of M. Clement's, which he calls a Derivometer, is an instrument to ascertain a ship's leeway. It is moved by a paddle, that may be placed under the keel at will, and is supported by a plug sliding in a tube like that of the Sillometer, but turning with the paddle and the rod. The motion is transmitted from the paddle and rod to two semi-circular dials, one of which indicates the leeway to larboard, the other to starboard. When at anchor, the instrument will show clearly the direction of the currents.

3. A third invention of the same gentleman, is a Submarine Thermometer. It appears from the thermometrical observations of many scientific navigators, that in seas of unfathomable depth, the water is not so cold as over banks, and that over banks near the shore it is less cold than over those at a greater distance, but colder than in the open sea.*

M.

The following is an extract on this subject from "Le Guide du Navigateur dans l'Ocean Atlantique: "

"Water is much colder over shoals than in the open sea; the shallower the water, the colder it is. "Water is colder over large than small shoals. "Water over shoals near the coast is warmer than over those at a distance from it, but still colder than the water of the open sea.

Water is colder over shoals in immediate proximity with the coast, than ove: those which are separated by a deep channel.

The preceding rules are not applicable to water inside of capes or in rivers; less agitated, more exposed to the action of the sun, and in intimate communication with the earth, it is hotter or colder than that out of soundings, according to the season of the year, and the temperature of the atmosphere."