THE WATER QUESTION.

Sir,-I do not know what Mr. Baddeley will say to the communication of " W. H.," in your last Number, about his cisterns close shut down and oft cleared out; but certainly those who sell Bohea for good Congou will feel grateful for the seasonable hint he has given them. In vain will old ladies complain that the tea is deficient in flavour: Mr. T-man will reply-" I assure you, I have not varied from the quality I have been accustomed to supply; if you find a difference, I should think the fault must be in the water. Do you know how long it is since the water-pipes were laid down in your neighbourhood? If they have laid long, and got half-full of earthy deposits, it is unreasonable to expect that, with water through such pipes, you should obtain a fine cup of tea."

The Water Companies will not, however, pass him a vote of thanks for going so deep into the subject, and finding mud where Mr. Baddeley's besom cannot reach it. "What!" they may exclaim, "take up all the pipes, and clean them, and relay them?" This is worse, by far, than Stuckey's Filtration Scheme !!

By the way, Mr. Editor, "W. H." must have overlooked your former notices of this scheme, or he would not altogether despair of getting clear water; neither would he strenuously recommend private filtration. If he will refer to your Number for the 30th of July last, he will see what is doing in this matter for the public good; and he will also find stated a very important defect in private filtration, which will save him from estimating it above its due value. As I consider this defect worthy of the special consideration of all your readers, you will perhaps excuse me, Mr. Editor, if I refresh their memories by a brief quotation:-" Such small filters, by the slowness of the process, destroy the carbonic acid gas which is contained in the water, and without which it speedily becomes offensive, putrid, and injurious to health."

I am, Sir, yours truly,

Old Kent-road, Oct. 19, 1848.

J. COLE.

THE COCKED HAT AFLOAТ. (From the Fifeshire Advertiser of 15th Oct.) At the special request of its ingenious inventor, we give the following truly graphic description of the launch of this nautical wonder, which took place, from the building-yard of Messrs. Brown, of Kirkaldy, on Wednesday last. We trust we need make no apology to our readers for its insertion,

as we feel assured they will be as much delighted with the description of the launch, which is from the pen of Mr. Dempster himself, as they were at the sight itself.-ED.* Launch of the Problem.

Sir,-On Wednesday morning the 12th October, 1842, the sun rose beautifully in the east, with light southerly airs, and sea smooth as glass, comparatively speaking. This being the morning of the day that I had pledged myself to the public that the Problem should be launched into her native element for solution, I felt happy at having a good day for the occasion.

The Problem was mounted on a cradle with 4 wheels, full-rigged, with all sail set, and my four equilateral flags (each of which answers for six numbers) displayed at the different mast-heads.

At 1 p. m., being nearly low water, two fine black steeds were yoked to the cradle which supported the Problem, when all moved off slowly but majestically down to the water edge, amidst the loud huzzas of numerous spectators. The cradle being removed, she sank gradually down in the sand about 2 feet, where she stood quite erect, without the assistance of anything to steady her; and, as there was but little wind, I thought proper to allow the sails to remain hoisted up, so as to gratify the many that were constantly gathering to see her, and expressing their admiration at the beauty of the rig, and their astonishment at her standing upright in the sand, with all sail set. An anchor was run out a considerable distance, to haul on when she floated.

At 2h. 30m. p. m., the tide coming in, the wind shifted round to the eastward, with an increasing surf on the beach, and at 5 p.m., the water having risen about 24 feet round her, the sand being softened and breeze increasing, the Problem went very gently down upon her bilge, with all sail set: a grand sight!

The sensation which now seized the thousands who were standing on the beach, witnessing the scene, I will leave you to judge, knowing what the feeling generally is before any new invention is tested. Some swore she would never again rise, whilst others said, that was just what they expected. It was a fine joke for those who were prejudiced, you may depend upon it; whilst others, who were friendly, I believe sincerely pitied me. The sails being lowered down, as the tide flowed the boat rose gradually, just as I was aware she would, until she became upright; but as the surf by this time was

• For a description of Mr. Dempster's system of building, see Mechanics' Magazine, vol. xxxvi. p.

504.

running rather high, every sea that came lifted, and again left her to bring herself up easily by the point below; she made several sharp rolls from one side to the other, as the men happened to be moving about in her, which no doubt appeared to some as though the Problem was to be a complete failure, if not a total wreck.

At length she got fairly afloat, and swam much to my satisfaction; and, as those on shore saw her moving outwards, they uttered tremendous shouts of applause, which were answered by us on board. I immediately ran for Kirkaldy harbour, where she was allowed to take the ground, and lay down as the tide left her; when the tide flowed she rose with her gunwale three inches out of the water.

Thursday forenoon, there being a moderate breeze of wind, I manoeuvred her about in Kirkaldy bay a considerable time, and I may now consider myself safe in saying that several of the most important points of the Problem are now solved, viz. :

1. She will rise off the ground without the water flowing into her hatchways.

2. She is less liable to take damage whilst bumping on a sandbank than any other construction.

5. She will be stiff under canvass, sail well, be very weatherly, and manœuvre in a smaller compass than any other built or rigged vessel that ever preceded this invention.

I am, Sir, Yours, &c.,
H. DEMPSTER.

On Thursday the 13th instant, the Orestes, 18, Commander the Hon. S. T. Carnegie, was hauled abreast of the dockyard, Portsmouth, for the purpose of practically testing the efficacy of her lightning conductors by a series of experiments by Snow Harris, Esq., F.R.S., upon whose plan the conductors have been fitted up. She was moored about 100 yards from the jetty, between which and the ship about midway a barge was placed, containing a carronade. A wire leading from the positive side of a powerful electrical battery in the Semaphore was attached to a cup of gunpowder on her main truck. Another wire leading from the negative side of the battery was attached to the gun in the boat. A short wire was placed on the touch-hole of the gun, and led over the gunwale of the boat to the surface only of the water, on the side nearest the Orestes. There was no communication between the ship and the barge.

The object was to show that immediately an electrical discharge reached the mast-head it passed down to, and was dispersed in, the water by means of the continuous line of conductors. This was proved thus-an electric battery in the Semaphore was discharged, the discharge passed along the copper wire from the metallic plate on the interior of the jar to the mast-head, its presence there was rendered apparent by the ignition of the gunpowder in the cup; it passed thence down the conductor on the

mast into the hull of the ship, and along the conductors on the hull into the sea. That it had arrived in the sea was proved by the ignition of the powder over the touch-hole of the gun in the boat, and the consequent discharge of the gun, because the only means by which this gunpowder could be ignited was the passage of the electricity up the short copper wire which connected the touch-hole of the gun with the sea; so that not only must the electric fluid have arrived in the sea, but it must have passed through it to this short copper wire in the boat. It is almost needless to add, that so rapid is the passage of the electric fluid, that the report of the discharge of the battery, the ignition of the powder at the mast-head, of that over the touch-hole of the gun, and the report of the gun itself, appeared simultaneous, notwithstanding the great distance traversed by the electricity; thus showing clearly and satisfactorily that the instant the explosion arrived at the main truck, that same instant did the conductors clear it of the ship and transmit it to the water.

Several experiments were then made, to prove that the principle held good in the case when the topmasts and top gallant masts were struck. These were very conclusive. The electrical current followed the continuous line, without at all diverging to those portions of the conductors which, by the striking of the masts, were placed in a position out of that line.

Wire-rope conductors were then considered, and the several objections to them fairly and conclusively stated. The danger of a man being killed in the bight of such a rope, while striking the top or topgallant mast during a thunder-squall, was most clearly proved by a very neat experiment. Such a case was represented by gold-leaf or paper, and when an electric shock was passed over the paper, the gold was burnt up in the direction of the man, but remained untouched round the bight of the rope.

The last experiment which was performed was with a view to prove at once the complete protection afforded by the continuous conductor, and the apparent impossibility of the least action taking place on metallic bodies out of it; thus practically refuting the supposition of any lateral discharge taking place. A model of a mast, about 10 feet in length, was made in parts, and an interrupted line of metal placed in the heart of it. Percussion powder, which it is well known will inflame with the least spark of electricity, was placed between these interruptions. On the outer surface of the mast a continuous conductor was placed, the extremities of which were connected at each end of the model of the mast with the extremities of the interior and interrupted line of metal. In order to make the experiment more complete, bands of metallic leaf were made here and there to surround the mast as hoops, together with other metallic bodies which could enter into the mast itself, and touch the internal line of metal. An intense shock of electricity was allowed to fall upon the upper extremity of the mast, where both lines of metal were in conjunction, with the view of discovering (since the electric matter had thus, it may be said, the choice of two lines) whether it would pass upon the metal within, or whether it would be dispersed between the two lines and pass down each, or whether it would only pass down the exterior line, and whether in passing down that line it could cause a lateral discharge to enter the mast, or in any way to affect the interior. This was a severe test, from the highly inflammable nature of the percussion powder, and it succeeded perfectly. As long as the continuous external conductor remained perfect the discharges of electricity were innoxious; when, however, the exterior conductor was removed, and a similar charge was thrown over the model, the mast was blown to pieces by the ignition of the percussion powder, evidently proving that if the previous discharges had in any way, or under any form, pervaded the interior, this effect would have resulted in the very first instance.

In repeating the experiment of passing the electric fluid through the Orestes, an accidental circumstance fully proved Mr. Harris's theory, that metals of themselves are not attractive, and that lightning will take the most direct continuous way to arrive at its course. The wire which led from the Semaphore to the cup containing the gunpowder at the mast-head of the ship was not properly placed, the bight touching the mast a few inches below the cup. The discharge, therefore, instead of continuing along the wire to the cup, was conveyed to the conductor. at the spot where the bight touched the mast, and carried through the ship, and thence by the seat to the boat where it fired the gun, leaving the gunpowder at the mast-head unexploded.

After Mr. Harris had concluded his experiments, Admiral Sir Edward Codrington said, that after what he had witnessed, he thought it but right publicly to observe that he felt perfectly convinced of the efficacy of the conductors upon Mr. Harris's plan, which, after the conclusive and satisfactory tests they had that day undergone, would no doubt be generally used throughout the navy.-Times.

NOTES AND NOTICES.

Sale of the Great Western Steam-ship —On Monday last the steam-ship Great Western was offered for sale by public auction in Bristol. The bidding was very spirited, but she was ultimately bought in at 40,000. The attempted sale of this powerful steam-ship gave rise to a rumour that she would not leave Bristol for New York on Saturday next, the 22d inst., as previously advertised. We have, however, reason to believe there was not the slightest foundation for such report -Times.

Wonderful-If True-Mr. Samuel Colt made an experiment with his terrible Explosive Engine, at Washington, on Saturday, Aug. 27, which is said to be completely successful. A vessel prepared for the purpose was shivered to atoms at a distance of five miles. It was a repetition, on a large scale, of the experiment he performed off the Battery, at New York, on the 4th July. There was an immense concourse of spectators present, including the President Heads of Departments, and the Mayor of Washington. Mr. Colt was near Alexandria; a signal gun was fired at Washington, and in about twenty seconds thereafter, a huge column of water rose suddenly into the air, and when it descended not a trace of the vessel was to be seen.—American Papers.

The Gold Mines of Russia.-Russia now yields four times as much gold as all the rest of Europe, and the yearly produce of this metal (400 poods, or 16,000 lbs.) is sufficient to load from forty to fifty sledges. The silver needs for its conveyance a caravan of from 120 to 150 sledges. The platina requires but three or four, and the copper, which is also conveyed chiefly by land, sets in motion 5000 sledges. By far the greater part of these metals comes to the mint in Petersburgh.-Kohl's Russia and the Russians.

New Paper Hangings.-A Liverpool paper thus describes a new style of paper hangings, recently introduced there from Switzerland. The effect must be very fine:-" The general character of the design may be styled Florentine; the ground work is white satin; the walls are divided into compartments by stiles of a rich gold colour, representing, with great accuracy, carved wood of intricate design; the panels are niches with drawings of deer, lions, swans, &c., each forming a complete picture in gorgeous borders of gilded ornaments and flowers, partaking somewhat of the Louis Quatorze style; the alternate panels comprise a species of filigree work, varied with drawings of flowers and gems, in which gilding is most tastefully and sparingly introduced, the whole being of the most exquisite design and execution. An exceedingly rich border runs round the top of the room, and one of a corresponding design round the bottom part. From the judicious employment of French greys and other cool colours, the effect is not in the least gaudy, but at once rich and chaste. The introduc

tion of this paper may be regarded as a new era in decoration, and will do much to relieve us from the sameness and insipidity which pervade even our best houses."

Foul Air in Mines.-Mr. Hardiman, a gentleman who made several experiments with Dr. Payerne in the diving-bell over the wreck of the Royal George at Spithead, has been trying other experiments at the Royal Polberou Consols' Mines, in St. Agnes, with the newly-invented method of purifying the air. The experiment was made at a depth of about 700 feet below the surface, and where the air was previously so vitiated that no person could approach the place, (a rise nine fathoms above the level,) a powerful air machine attached to the engine rods was put to work some time ago, which barely furnished air for three men with candles to exist. The method of purifying air was brought into action after this air machine had been thrown out of use, and although there were at that time no less than 15 men with candles in the rise, the air in ten minutes was so renovated that all breathed with comparative ease; the improvement was even visible, inasmuch, that where three candles were until then with difficulty made to burn, ten or more now burned freely. As a further test, two holes were blasted, and under the old method no man could approach the top of the rise until half an hour after the explosion, and in some cases longer, but the machine so quickly dissipated the smoke that in four minutes the men were at their work breathing air comparatively pure, and refreshed with the additional advantage of being as cool as at the surface, although there were, as before stated, 15 men in

the rise.

Wreck of an Iron Steamer.-The Brigand iron steamer, of 600 tons, and 200 horses power, has been unfortunately lost on the Scilly Islands. From the following account of some of the circumstances of the disaster, it will be seen, that to the excellent system adopted in iron ships, of building them in several distinct water-tight compartments, the passengers and crew were in this instance, most probably, indebted for their lives. "The Brigand sailed from Liverpool for London at 2 o'clock on Monday afternoon, and proceeded safely on her voyage until 5 o'clock on Wednesday morning, when they saw the St. Agnes' light, which, from the refraction of light, the weather being very hazy, they conceived to be at a considerable distance they were then steaming at 12 knots an hour: suddenly the man on the look-out at the bow sang out "Breakers ahead!" which they distinctly saw, but too late, unfortanately, for the rate at which they were going was such that they could not stop her; and, although they put the helm hard a-port, to endeavour to shave the rock, the vessel immediately afterwards struck most violently, and two plates of the bluff of her bow were driven in. She rebounded from the rock, but in an instant afterwards she struck again, broadside on, the force of which blow may be in some measure conceived from the fact, that it actually drove a great portion of her paddle-wheel through her side into the engine-room. The vessel was built in four compartments, the plan adopted in iron ships, or she would have gone down instantly, two of her compartments being now burst, and the water rushing into them at a most fearful rate. By the two shocks four and a half plates were destroyed, and four angle irons were gone in the engineroom. The two compartments aft being, however, still water-tight, she continued to float, and every exertion was used by her commander, Captain Hunt, for upwards of two hours, to save her, when the crew took to the bats, and shortly afterwards she went down, about seven miles from the rock, in about 45 fathoms of water."

INTENDING PATENTEES may be supplied gratis with Instructions, by application (postpaid) to Messrs. J. C. Robertson and Co., 166, Fleet-street, by whom is kept the only COMPLETE REGISTRY OF PATENTS EXTANT from 1617 to the present time).