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it is said, consists in reducing the scales to powder, by which means the “essence” is composed of a mixture of the enamel and the gelatinous substance it covers, and hence its liability to putrify. Reaumur long endeavoured to discover means for preserving it from decomposition. It is now, however, preserved in ammonia. How much superior, and yet how simple, is the Chinese plan 2 Perhaps the enamel or nacreous covering of the scales of fish generally is capable of being employed more largely in the arts: it appears to be sui generis, and seems hitherto to have escaped the scrutiny of organic chemistry. To prepare the nacreous paste for use, an adhesive property is imparted to it by the addition of a little fish glue, and an infusion of lichen. When employed, it is put in a small cup, which is placed in tepid water. Beads made of the vitreous substance employed in making artificial gade are dipped into the paste, which gives them a splendid pearly covering: strings of such beads can be had so cheaply, that the poorest children can procure them. When exposed to friction or moisture, the gemmeous matter easily rubs off, which prevents the general use of these elegant ornaments, a difficulty which Beckman, in his “History of Inventions,” informs us was overcome in France at the suggestion of a lady, who proposed to the artist the introduction of the preparation into hollow beads, thus bringing the invention to perfection. If the Chinese failed to perfect the art of making factitious pearls, they have admirably succeeded in effecting the growth of the genuine testaceous gem. Imperfect and contradictory accounts of the mode of producing pearls in mussels having at different times appeared, and as the only place of culture is within a few days’ journey from Ningpo, Mr. Consul Hague and myself despatched an intelligent native to make inquiries on the spot. concerning the art, and to procure specimens in different stages of growth: the following result of these investigations, made on two successive journeys, may be relied on as authentic. The practice of the art is confined to two coterminous villages, near the district city of Tehtsing, in the northern part of Chihkiang, in a silk producing region. In the month of May or June large quantities of the mussel (.js/oilus cygnus) are brought in baskets from the Tăhti, a lake in Kiangsti, about thirty miles distant, the largest anongst the full-grown being specially selected. As their health suffers on the journey, they are allowed a few days respite in barnboo cages in water, before being tortured for the gratification of human vanity, when they are taken out to receive the matrices. These are various in form and material, the most common being pellets, made of mud taken from the bottom of water-courses, dried, powdered with the juice of camphor-tree seeds, and formed into pills, which when dry are fit for introduction into the unfortunate subject: moulds which best cxhibit the nacreous deposit are brought from Canton, and appear to be made from the shell of the pearl oyster; the irregular fraginents thus procured are triturated with sand in an iron mortar, until they become smooth and globular. Another class of moulds consists of small images, generally of Buddha, in the usual sitting posture; or sometimes of fish: they are made of lead, cast very thin, by pouring on a board having the impression. Pearls having these forms have excited much surprise, since they first attracted the attention of foreigners, a few years back. The introduction of the peari nuclei is an operation of considerable delicacy. The shell is gently opened with a spatula of mother-of-pearl, and the free portion of the mollusc is carefully separated from one surface of the shell with an iron probe : the foreign bodies are then successively introduced at the point of a bifurcated bamboo stick, and placed in two parallel rows upon the mantle or fleshy surface of the animal: a sufficient number having been placed on one side, the operation is repeated on the other; stimulated by the irritating bodies, the suffering animal spasmodically presses against both sides of its testaceous skeleton, keeping the matrices in place. This

being done the mussels are deposited one by one in canals, or streams, or pools connected therewith, five or six inches apart, at depths of from two to five feet, in lots of from five to fifty thousand. If taken up a few days after the introduction of the mould, these will be found attached to the shell by a membranous secretion, which, at a later period, appears as if impregnated with ealcareous matter; and, finally, layers ...} nacre are deposited around each nucleus, the process being analagous to the formation of calculary concretions in animals of a higher development. A ridge of marl generally extends from one pearly tumor to another, connecting them all together. About six times in the course of the season several tubs of night-soil are thrown into the reservoir for the mourishment of the animals. Great care is taken to prevent goat manure falling in, as it is highly detrimental to the mussels, preventing the secretion of good nacre, or killing thern, according as the quantity may be great or small. In November the shells are carefully collected by the hand, the muscular portion removed, and the pearls detached by a sharp knife. If the basis of the pearl be of nacre, it is not removed, but the earthen and metallic matrices are cut away, melted yellow resin poured into the cavity, and the orifice artfully covered by a piece of mother-of-pearl. In this state these more than semiorbicular pearly pellicles have much of the lustre and beauty of the solid gem, and are furnished at a rate so cheap as to be procutable by all who care to possess them; they are generally purchased by jewellers and others, who set them in tiaras, circlets, and various ornaments of female attire. Those formed on the image of Budha are finished in the same manner, and are used as ornaments and amulets on the caps of young children. A few shells are retained, with their adhering pearls, for sale to the curious or superstitious, specimens of which have, by this time, found their way into the principal public and private cabinets of Europe and America. They are generally about seven inches long, and five broad, containing a double or triple row of pearls or images: as many as twenty-five of the former and sixteen of the latter to each valve That the animal should survive the introduction of so many irritating bodies, and in such a brief period, secrete a covering of nacre over them all, is certainly a striking physiological faet. Some naturalists, indeed, have expressed strong doubts as to its possibility, supposing the pearls were made to adhere to the shell by some composition; but the examination of living specimens in different stages of growth, having both valves studded with pearls, has fully demonstrated its truth. A tinge of yellow is found over the whole inner surface of some shells, showing that the more recent secretion of nacre by the suffering animals was unnatural; the flesh of all, however, is eaten. Above five thousand families are represented as being engaged in this singular branch of industry in the villages of Chungkwan and Siau chang ngan: they, however, mainly derive their support from cultivating the mulberry, and in rearing silk worms, and other agricultural occupations. Those who are not expert in the management of the shells, lose ten or fifteen per cent. by deaths; others lose none in a whole season. The invention is attributed by the villagers to a native of the place, ancestor of many of them, named Yu Shunyang, to whom a temple has been erected, in which divine honours are paid to his image. He lived about the close of the fourteenth century. The topography of Chihkiang mentions a pearl sent to Court in 490 A.D., which resembled Buddha, being three inches in size. . The resemblance was, probably, fanciful, being but an irregular form of pearl produced in the usual manner. Those now made are but half-an-inch long, and while in the shell have a bluish tint, which disappears with its removal from the matrix. In the manufacture of factitious pearls, we find that the Chinese , anticipated the French, affording an instance of independent invention; and in effect. ing the growth of true pearls, they anticipated the discovery of Linnaeus, which must be taken as another instance of the same character. 1t has been

suggested that the great Swedish naturalist had heard of

the Chinese method, or at least he was indebted to them for the idéo mere, but there is no ground for believing that hilosopher capable of such an artifice as this supposes. t will be remembered the government of his country liberally rewarded him for the discovery, and that the rank of nobility so honourably conferred upon him appears to have been prompted by the same circumstance. Coincidences of this kind have been too numerous to authorise any doubts, particularly where they asperse the reputation of the high priests of science.

In an elaborate and interesting tract on pearls and pearl-fisheries, in Chambers' Miscellany, allusion is made to a statement respecting a method of producing pearls in China, which must be taken as apocryphal. Mother-ofpearl beads are said to be strung on a thread and thrown into the live animal, so that in the course of a year sporical pearl-beads are found, resembling the real pearl. Specimens are also referred to in the cabinet of the British Museum, from which the pearls had been cut away, exhibiting a concave depression, and hence it was inferred that the nuclei had been introduced when the animals shells were younger and thinner. The internal shell is never scraped off, and, as is represented, for the insortion of a nucleus, the depressions referred to are occasioned by the process of absorption which takes place under the foreign body, while secretion is operating above. It has also been stated that specimens have been met with, in which pieces of wire had been thrust through a prioration made in the shells as the foundation of pearls. None of this description are known to pearl-dealers in this part of China. When peari-mussels are suffered to remain several years (which is rarely done), with these foreign bodies in contact with their shells, the morbid produet is formed of so many layers of nacre as to afford Pearls of most beautiful character. All experiments of this description appear to have been tried in the fresh-water molluscsa: were the attempt made with oysters, particularly with the pearl procina species, it would doubtless prove yet more successful. Perhaps now that the Californian fisheries are within the sphere of their observation, some of my ingenious countrymen may be found willing to undertake the enterprise. It is very possible that the art is susceptible of improvement could it be carried so far as to render the health-destroying and perilous pursuit of diving unnecessary; however great the profit which might thereby accrue to trade or art, it would be of small conseThence compared with the boon it would confer on humanity.

Xingpo, August, 1853.

GOLD CRUSHING AND WASHING.

Mr. John Phillips, in a further communication on this subject, in reply to Mr. Stansbury, says:—“Mr. Berdan, Personally, is entitled to be treated with the utmost re*Poet; and I believe that nobody denies that there is 8"at ingenuity and merit in the machine he has inMonted. But that its performances have been overrated o, found by referring to the published reports of Mr. Berdan's agents, wherein it is distinctly stated that the inachine of four pans would pulverize, wash, and amalKantate about 40 tons of ore, of average hardness, in ten hours, with fifteen horse-power, being one-third more work in crushing alone than has ever been done by "Yother machine. Compare this with Professor Ansted's "P"s, in which he assumes’ that the four basins would oire an engine of twenty five horse power, and that "ous of average stuff might be reduced per day. I Pourne that by the words “to work continuously,” he *ans a day of 24 hours; but admitting it to be only 10 hours, we have here the 40 tons brought down to ", while the moving force is 25 instead of 15. This

will suffice to prove my point, that the power of the machine has been overrated; and I have only to add, that it is far from my wish to say anything that may be offensive to Mr. Stansbury, whose interesting paper I read with much gratification ; but the subject is one open to discussion and comment.”

^* ~... * ~ *-*. oilst Cotropolithtt. —oFLAX, AND ITS PRODUCTS, IN IRELAND. contributed BY was. CHARLEY, soy MoUR HILL, BELFAST. LETTER V. After making room in my last communication for Mr. Lee's rather long defence of his patent, I had not space enough for Mr. Williamson's letter on the subject, or the memorial of the merchants already alluded to. I now beg to transcribe these documents winich, in my opinion, point out the defects and errors of Mr. Lee's patent so very plainly and decidedly that very little can be added by me. Letter from Mr. R. Williamson, of Lambey House, to the Secretary of the Linen Board, Dublin, upon the subject of Mr. Lee's Machinery. January 13, 1816. “Since I did myself the favour of addressing you last, a meeting of the trade has been called at Banbridge, to re-consider the business of Mr. Lee's patent preparation of flax. This meeting was assembled at the instance of the patentee, and for the purpose of confuting, personally, the arguments, and disproving the experiments, that had been adduced against his project ; and as my letter formed the principal topic of discussion by Mr. Lee, it is incumbent on me to defend it. He there asserted, as I am informed, that my experiments were incorrect, and my deductions, of course, unfounded. He endeavoured to prove this by producing, from his machines, a few ounces more of fiax in the same time, than was mentioned with the samples sent to the Board. I must beg leave to call to your recollection, that the sample sent with my letter, was from green flac, the state in which it is generally, and necessarily pulled here; and that Mr. Lee's experiment was from flax in a more mature state, and, as we conceive, unfit for our finer fabrics; for, in proportion as the flax is ripened, the received opinion with us is, that the fibre becomes harsh. The experiment stated by me was performed in iny immediate neighbourhood by Mr. W. J. Handcock, and his accuracy, with some allowance for a trifling diminution of quantity, by the inexperience or inexpertness of the operator, was unquestioned. On the ground of the additional quantity then produced, the patentee wished for a certificate from the persons o which was refused, on the score of a new trial having Jeen agreed to be gone into, and the result is to be reported at a future call of the trade. The meeting was attended by the Marquis of Downshire, and the thanks of the trade are due to his o for his zealous and undeviating regard to its interest, and the patience he evinces in the investigation of any measure proposed for its advantage. This sort of patriotism is an heir-loom in his Lordship's family; it belongs to his great possessions, and I trust will go down to his posterity. It is a bequest of that first Marquis, whose memory will still be venerated by the linen trade. The consideration of Mr. Lee's patent in being referred to the trade, stands now as was at first suggested, though I am satisfied there can be but one rational opinion as to the success of the project. It is now the middle of January, and not a single piece of linen has, 1 believe, yet been manufactured from Irish flax prepared by the patent machines. I shall, however, give Mr. }. all the advantages of his experiments in this impeachment of one portion of my letter, and admit that a man may, under his direction, and with his assistance, clean 10 lbs. of ripe flax in a day a thing not practicable with green flax). What proportion does that bear to the quantity produced by our mills, in which one man can clean a great deal more even of Mr. Lee s flax, and from five to six stone in the same time of our own, prepared in our own way, without the intervention of His Majesty's Royal Letters Patent. That the enhanced value of steeped flax is in an increased ratio to the quantity, I shall presently take the liberty of stating. Mr. Lee has taxed me with the temerity of a premature report. The truth is, that I wished to do away, as soon as possible, the mischief of an error which some of us had been led into, by a dazzling but illusory experiment. I own, with extreme regret,

that my first letter was premature, and I used the earliest means of preventing the injury which might have resulted to the fiax‘owers and manufacturers of the North of Ireland, where this etter unluckily had circulation. Your recollection of the early history of this sealed patent need not now be recalled. Its want of the usual specification, lest the discovery might be transinitted to foreign nations before we had the advantage of it, you can well remember. I need not particularise the clauses of that private Act of Parliament, by which the mystery was concealed, though the patent was in exercise. These things are on your minutes, and the inutility of the precaution will be discovered by a reference to the accredited report of Mr. Durno, British Consul at Memel, on the cultivation of flax in Russia, Prussia, and Poland. This gentleman informs us that the plan of preparing flax without steeping had been practised, and afterwards exploded, in that country, as being more laborious, more expensive. and also attended with more breakage of the harle, or fibre; and that there is less reason to doubt of the steeping process being best, as it is almost universally adopted in that part of Poland where these articles are most extensively and best cultivated. To this account I beg leave to add a communication from Rotterdam, in September last, from M. V. Wallen, a very respectable and inteli goint gentleman, to a friend of mine here: I give it in his own words:— As to what you wrote me of the manner of breaking flax by machines, without waterrotting or dew-rotting. I presume you will soon repent of that invention: we have tried it long since, but the linen made from it was of no lasting or strength,’ This latter gentleman then describes another invention of a M. Bralle, of Amiens, of as little utility. I do not mean to infer that Mr. Lee was aware of the previous trial and condemnation of his alleged discovery, where he thus guarded himself against continental pillage. I have too much respect for his candour—too much regard for his veracity and common sense—to suppose that he had informed himself of these facts. As to the more’ty of the patent machines, that may be fully conceded to him, without risk of invasion. If this gentleman, however, without pursuing in the mystery of concealment things in their own nature generally impracticable, if not impossible—if he had not been inspired with the dreams of an iunrnense remuneration—if he had entered into a liberal communication with persons of equal, or superior ingenuity and knowledge, with his own—these errors could not have been got into ; and his plan, it is to be doubted, has as little to do with science, as it has with experience.

“I have already mentioned to you the fatal and incurable defects of the patent flax, in the shortness of the draft in spinning, from its being cut traversely, in the difficulty of joining, and the consequent brittleness of the yarn in weaving. These had qualities are further corroborated, and can be best ascer. tained by the examination of our most intelligent and respectable manufacturers. The trials made by them have been on flax imported from Mr. Lee. They attest, that neither the white nor the yellow flax can be joined with facility or strength. They find to use their own technical terms) that the warp of the white yarn loses the dressing, and that both it and the yellow brush into lamps at the joinings during that operation; ilat the yarn breaks in the reed-walk and between the loan and the geara, losing, at the same time, its twist, so that when thus broken it cannot be effectually tied ; and, from not bearing the stroke of the slots, that no thickness of fabric can be attained. This weakness is equally felt in the west, which gives way in the straining of the temples, occasioning frequent breaches in the selvage. Such is the decided opinion of those who have triad the patent flax. The evil seems inherent in the preparation. It appears, therefore, that without the fermentative process of steeping and grassing, all mechanical means of separating the fibre have been unsuccessful. The objection is fatal alike to the quantity and the quality. In short, this project seems to have failed in its claim to originality of discovery, in its means of attainment, and in its principle and end. When such are the obvious defects in the system any observations as to blaching will be unnecessary. The facility in this point has been greatly overrated. If the oil is previously removed, the linen, when put to bleach in the usual way, must be injured on the grass before the sprit can be discharged. To effect this it must receive a double dose of oxy-muriatic acid; but, indeed, the whole scheme is so illusory, that I should offend your common sense by further practical illustration. The flax produced from the steeping process has been so far, without one dissentient voice, laced beyond , all comparison above that prepared by Mr. Lee. It does not belorg to me to go into scientific reasons for this preference—it is enough to feel from our prosperity that we are right. It is observed by

Fourcroy and his late editors, that the phenomena of vegetable fermentation is not yet sufficiently studied or understood. When this reproach is cast on the chemist, it would be unreasonable to visit it on the flax-grower or manufacturer. All we know is that humidity, or the presence of water, is necessary to produce this vegetable fermentation—that the putrid fermentation in steeping does not extend to the wood or fibre of flax—it reaches only the gluten or mucilage which attaches the fibre to the wood, rendering them easily separable, and thus, by a simple process of nature, attenuating the fluid which pervades the fibre itself. The fibre in this process becomes softened and ameliorated, and fitted for that beautiful linen in which Ireland so peculiarly excels. A certain portion of oily matter is esteemed requisite to protect the yarn from friction in the loom, and in proportion as yarn is divested of its oil we depri e it of its tenacity. It is unnecessary to add that the peculiar fitness of our climate and country, with its humidity, and springs, and waterfalls, bleaches and finishes what the spinners and manufacturers have so well begun. “Now, what does this new plan attempt to accomplish? It presumes to disregard the deductions of science, and to set at nought our practice and our proficiency. The machine is to be the substitute for the flax mill, and exploded as this scheme has been by our cotemporaries on the continent, its propounder ventures to say, for your skill and your success you shall have my patent. And what is this basket of brittle ware in due time to produce to the possessor? One hundred thousand pounds, and thirty thousand a-year during the period of the patent.' But we are to pause before we reject this donation of his patent. We are told by him, ‘ If you do not accept my offer, your trade will go to England; the new flax is peculiarly fitted for millspinning, and machinery is already waiting to give you yarn of 20 or 30 hanks, in the pound. If Mr. Lee's plan of millspinning were indeed practicable, our trade would go to England; the flax would 'ollow the machines—the machines would follow the power—and the skill and the capital, and all would be engulphed in the coal pit! The misery that would ensue to an impoverished peasantry, injured as they would be in morals, and habits, and health. I shall not state, because I believe the whole to be an icle illusion, the marvel of a day, not to be heard of hereafter. As a member of the trade, I have now performed what I conceive to be my conscientious duty, in thus, most respectfully, submitting my sentiments to the Linen Board, and 1 beg you will have the goodness to lay this letter before it.” This Mr. Williamson was one of the most intelligent linen merchants of his day : (a) he appears to have had a great dread of the factory spinning system, and though the results have hot been so injurious to public principles and health as he anticipated, yet it must be admitted the moral argument in favour of hand spinning at home in the parents' cottage is almost irresistible. The laws of progress, however, must be obeyed in commercial commuinities on pain of losing their trade or manufacture. Belgium and the other continental nations neglected the new system of mill-spinning, and, in consequence, a large proportion of their linen t ade was transferred to Ireland, never, in all probability, to return. After putting one's hand to the plough there must be no looking back—no hankering after days gone by, but a firm resolve to keep in advance and to make the best of every difficulty that may arise. It is this feeling and this principle that has so successfully guided the linen merchants and manufacturers

(a) Mr. John Williamson, his father, was also a man of importance. In 1762 the Magistrates became more vigilant in carrying out the laws at the Brown inn market." The consequence was great clamour and excitement among the masters, who, at Lisburn, issued the following curious proclamation (See “Newry Mag.," Vol II.):—" This is to give notice, to all gentlemen, manufacturers, and weavers, to meet in a body like valiant and honest men, at Lisburn, on Tuesday next, that we may oppose the unprecedented and oppressive means which are to be used against us by the merchants, and to bri them to reason by fair means; and it that will not do, other means must be used ; and let us, like Demetrius and his craftsmen, stand valiantly up for our Diana, for our craft is in danger." The comparison is perhaps more truthful than happy. The same authority states that the mob assaulted Mr. Williamson, who narrowly escaped serious injury, which was the more scandalous from the high character he bore for probity and generosity.

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of the North of Ireland. The following is their opinion of Mr. Lee's patent.

* Memorial from the Linen Merchants of Belfast and Loburn upon the subject of Mr. Lee's Joachin, ry.

“To the Right Hon. the Trustees of the Linen and Hemoen Jianufactures. “February 27th, 1s16. “We beg leave most respectfully to address you concerning sundry Letters Patent granted to Mr. James Lee, of Middlesex, as far as they relate to the linen manufacture of Ireland. It appears upon reference to your Minutes, that Letters Patent, touching the interest of our staple manufacture, have been hitherto graciously referred by his Majesty to the Lord-Lieutenant of Ireland, and thence to the Linen Board; and your Minute of the 2nd of December, 1788, records your declaration, that there is no statute in this kingdom authorising the grant of such patents. “We therefore pray, that as the late grant to Mr. J. Lee may form an injurious precedent, and still more so from its want of an open specification, you will take measures to do away and prevent the recurrence of such unauthorised precedents, contrary to your said Resolution. “We beg leave to inform you that the patent machines of Mr. James Lee have been found of no use in our manufacture, and that the plan has not originated with the patentec. We, therefore, pray, that your premiums may be restored to their accustomed channel. “We respectfully suggest that the projects of o unconnected with our concerns, and who are generally wanting in ..". knowledge, ought to be received with extreme caution, rom the injury the trade has suffered from such projects and the waste of public money. “Resting upon the high reputation to which our great staple has attained, by its own means, at home and abroad, we entreat your attention to this our representation. “We are, my Lords and Gentlemen, &c, &c. “joy 34 gentlemen in the Trade, and resident near Belfast.” If anything were wanting in Mr. Williamson's letter, this brief protest of the practical men in the trade would be enough to decide the merits of the case, but the two documents jointly form an authority not to be questioned. Mr. Lee admits he was treated with great consideration and kindness, and therefore the failure of his propositions cannot be ascribed to any unwillingness to improve, but entirely to their own inherent defects. As this patent caused great commotion in its day, and as thousands of pounds were spent in testing its utility, the full account I have given will I am sure be acceptable to those who take an interest in such subjects. In my next paper 1 purpose treating of the recent patents for the improveInent of flax manufacture. |N.B.-Errata in printing last letter (Letter IV.):— Page 28, col. 1, line i2, for greatly, read eventually; line 25, for automatic, read unromantic; and for crusted, read trusted; line 40, for obserably, read absurdly.]

A CHAPTER OF INVENTION. RUThven's propeller.

SIR,--Some score years back the child of Watts' brain, the steamboat, had its material birth in Scotland, Whence it spread far and wide on both sides of the Atlantic. The “saw-mill on one side and grist-mill on the other" of the Mississippi boatman—the paddleWheels—have since been much damaged by the screw : but both screw and paddles are now, if reports be correct, likely to be set aside by a newer invention, save in the * of Mr. Brunel's proposed vessel, in which, it is said, both screw and paddles are to be used together, and wedded to fame. More than a dozen years ago a certain John Ruthven, doendant, it is said, of the stern old Rizzio-killer !ollowed the more honourable vocation of printer, changin obsequently to that of press-maker, in the city of ki kie, in which he acquired fame. He had sundry sons, "d two of them (one named Morris West Ruthven) were

brought up under their father as engineers, and Morris subsequently became an engineering manager in Rotherhain. The idea caine somehow into John Ruthven's head, when turned of fifty, that steamboats were not perfect, which, doubtless, was a presumption “in a printer bodie with a wheen auld farrant notions.” But he could not be easy or rest till he had obtained a patent Inonopoly of fourteen years for his invention, to carry which into effect he recalled his son Morris from Rotherham to engineer a boat to put in practice his sire's ideas, in which a brain of a mathematical turn much helped him. The idea was, by means of a water fun to pump water through the fore p irt of the bottom of a vessel, and discharge it at the side farther aft. The water fan was, in fact, neither more nor less than what is known far and wide as Appold's pump. This may be understood generally, without going into the more detailed question of the curves of the blades. Through good report and ill report, John Ruthven stuck to his text—that his propeller was the true one, and, to back his opinion, began to construct a boat. lf we examine the action of any common pump we find that a certain power on the handle is required to lift the column of water. If the pump were placed on springs,

just balancing its weight, it would be found that, instead

of drawing the same amount of water up, the pump would be partly drawn down by the operation of the sucker. Place the pump horizontally in a vessel floating on water without the springs, and the result would be that the vessel would be drawn forwards, while water was drawn into the vessel, unless the vessel was disproportionately heavy for the size of the pump. A pair of pumps, working alternately, would keep up constant motion, greater in proportion to the speed of the pumps. But there would be the great disadvantage of the reciprocating action causing jerks, concussion, loss of power, and consequently diminution of speed. All this, doubtless, passed through the mind of John Ruthven, inducing him to make his pump with a continuous circular movement, in short, a water fail always revolving in one direction. Much he strove to acquire friends to help him; but there is no rest, no hope for the non-practical schemer, save in his own strength. An open boat, about thirty feet long, and five feet wide, was finally built, with an engine and vertical boiler. She came to the Thames, and was christened by the not euphonious name of the “Squirt.” from her water-projecting faculty. It appears that she was tried, and faintly praised by some of the government authorities. Funds probably were low, with the inventor, and the boatlaid long on the river bank, an object of curiosity to many, but not kept in constant work, as might have been done by a more prosperous owner. He tried to find a patron among the London, engineers unavailingly. He went with his son to the United States, and tried all the shipbuilders, but also unavailingly. He returned to Scotland, but not to despair—that is the last thing in the blood of a true inventor. The man was clearly a schemer—a favourite term of reproach by practical men, “who never make a mistake,” because they never do anything but what has been done before—in reality, passing their time in one continuous mistake, for which the unthinking call them “safe men.” Such men so hate schemers, that they would shake their heads if any one were to allude to the “great scheme of Creation,” and consider it was rebelling against Providence. Columbus was fifty-three, when by grace of the true womanly, Isabella, he sailed on his first voyage. John Ruthven had turned sixty, when one day he for-gathered with one John Anderson, the greatest fish merchant of Edinburgh, who liked not to sell “caller haddies,” and call them “lives o' men.” Keen-witted as any Christie Johnstone, he saw that fishing in an open boat caused risk and uncertainty, and that men's lives would continue to be lost and customers to be disappointed, and the finest fish be missed, unless some means could be contrived to reach, and return quickly, from the deep sea. “Yon steamers might do, but the fashous paidles wad just frichten a' the fish, and the screw thing was nae better, baith screw an’ paidles wad just hitch i' the nets, and tear them a' i' pieces.” In the very nick of time, John Ruthven showed his scheme, and John Anderson clutched it. His plain practical sense told him it was right, and he determined to set going, if possible, a company for deepsea fishing. The company was organized, and Lord John Scott, a descendant of the “Bauld Buccleugh,” did a better deed for humanity than ever his ancestor did in a border raid, in becoming its chairman. But all was not yet achieved. There were cautious men amongst the directors, who liked not to meddle with the untried. “Why not have a common steamer, that all the world understood 2" “And frighten all the fish '" exclaimed the irate fishmerchant. At length the disputants agreed to refer the matter to an engineer. Daniel Kinnear Clark was chosen. He gave in a report that the plan was consistent with sound principles, and that if properly constructed the vessel would be successful. So it was finally settled—an iron vessel of one hundred feet in length, and fifteen feet beam, was laid down at Granton, to the lines furnished by Morris West Ruthven, with bottom plates 5-16th of an inch, sides 1-4th of an inch, top sides 3-16th of an inch. An iron tube forming the vessel's kelson had a fan fixed in it, the water entering through holes in the bottom, passing through the fan, and escaping at either side behind the fan. Mr. D. K. Clark states that at the first trial, the vessel made six knots from Granton-pier down the Forth. The second trial is thus stated to have taken place on Tuesday last: “The maximum speed attained was about twelve miles an hour, and going at full speed she stopped within fifty feet. She appeared standing stock-still all the time we were running, and those on board declared they could not be aware of her moving without looking over her side.” If this report be correct, it is remarkable as a first essay, and may warrant more at a future time, when experience shall have corrected defects. It is probable that great speed will ultimately be obtained by this propeller, and there is a convenient power of multiplying the numbers; and by means of these vertical shafts in distinction to the horizontal shafts of the paddles and screw propellers, there need be no inconvenient interference with the steerage of the vessel. Moreover, the engine might be placed on deck, if preferred, or in any other position. The vertical shafts give great facilities for this. In planning a large steamer some years back, the desirability of vertical shafts for convenient stowage of the engine occurred to me, and I had a model made with submerged paddles beneath the bottom. Iłut the inefficiency, and the inconvenient exposure to accident, caus me to lay it aside. Subsequently, the idea o curred of a succession of lateral or bottom fins or scales, to be slowly opened and then rapidly closed against the vessel's side and bottom, so as to ject the water astern., Supposing ro difficulty in the detail, and the whole length of the vessel to be so provided, it is probable that the speed gained would be considerable. But with Ruthven's propeller the objects aimed at seem to be accomplished; the machinery is out of the way, and when not at work, the external hull is free from all ob. structions to sailing, without any manipulation whatever, and with a facility of multiplying at pleasure. There is every probability that this new plan will work a revolution in steam navigation, and facilitate the structure of much larger vessels than have yet been proposed. There is but one apparent disadvantage, the sucking in matter, to stop the entrance orifices of the pumps, as in the pro

cess of “thrumming a sail” to stop a leak. But, probably, the reverse action would suffice to clear them. I am, Sir, yours faithfully, COSMOS, Dec. 11, 1853.

SUGAR OF LEAD REFUSE.

SIR,-Having reason to believe, from what passed in conversation with a Chemist and a Fellow of the Royal Society, that the manufacturers of sugar of lead are not aware of the nature of a greyish powder produced by the solution of that metal in vinegar, and that, thinking it of no value, they allow it to be thrown away, I beg to mention that it consists almost entirely of silver, in a state of very minute division.

Mineralogists have long been aware that most ores of lead contain a greater or less per centage of silver, and hence it was natural to conclude that the lead procured from them should also contain silver, But it was reserved for an eminent manufacturing chemist, who was remarkable for turning chemical refuse to useful purposes, to examine this powder and collect it in such quantities as in the course of years to supply himself with many valuable articles of plate.

Your obedient servant,

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SIR-In the report of my observations on the Safety Lamps, made at the meeting of the Society of Arts, on Wednesday evening last, and published in the Journal of Friday, December 9th, there are some mis-statements which I should feel greatly obliged to have corrected. It is stated the light is reflected through glass. There is no glass about the lamp, but the reflector is of German silver, which should be, horizontally, of a parabolic form, the light being placed in the focus of the parabola. Behind the reflector, and between it and the outer case of the lamp, is a cavity, which I suggest may be partly filled with water, which would delay the overheating of the lamp, if inadvertently left burning in an explosive atmosphere. The funnel spoken of, is the chimney, up which the heated air escapes through a perforated metal plate at the top. The air is admitted through the wire gauze in front. When the lamp is placed in an explosive atmosphere, the gas burns against the inside of the wire gauze, which prevents a further supply of oxygen reaching the wick of the lamp, and it is therefore extinguished : but the gas would continue inflamed within the gauze so long as the lamp retuained in an explosive atmosphere. It should, therefore, be immediately removed, or the flame be extinguished by covering the wire gauze with the hand, or by other means. The pricker, with which I mentioned the lamp exhibited by me was not provided, is the contrivance for trimming the wick, which could be attached with equal facility as to the common I)avy lamp. It has no connection with the lock. The lamp is locked by means of a screw in the top part, by which the top can be fastened to the base of the lamp when in its place, so that it cannot be taken off without the aid of a key. I am, Sir, your obedient servant, BEN. ISIRAM. Wentworth Woodhouse, Dec. 12, 1853.

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