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SIR H. DAVY'S METHOD OF PROTECTING THE COPPER OF SHIPS. 275 through a rag into another bottle; gle adhesion of any kind, and, as far if any of the caoutchouc be not dis. as could be judged from the smoothsolved, add more spirit, and proceed ness and appearance of the copper, as before.' When I dissolved caout: it had not been at all worn by any chouc, it was to varnish a sinall gas chemical corrosion. The iron, which balloon. I'mixed an equal quantity was about an inch and half in thickof boiled linseed oil with the gum, ness, is considered a sufficient proand think it would be advisable in tector for two voyages more. this case also, as it would contribute 2. The Elizabeth yacht, belonging to keep the leather softer, and inore to the Earl of Darnley, was protected impervious to the water, and makes by two pieces of malleable iron in the varnish much easier to be used, the stern, in May last, equal to about as, without it, the brush which you 1-125th of the surface of the copper. use will soon be clogged. A quar- After being employed in sailing ter of an ounce of caoutchoue will during the summer, she was examake more than three ounces of the mined in November, when her botsolution by measure; and if it be tom was found free from adhesions: mixed with the oil, the spirit may, of any kind, and apparently unin a great measure, be evaporated, touched. The copper was brigbati, by placing the solution in a warm and even the nails not tarnished. In oven, no cork being in the bottle; the course of the summer a few small but I do not consider that any ad- barnacles had adhered to the rest of vantage can be gained from this. In iron, which were easily and immestraining, care must be taken to daub diately washed off; but no weed or the hands, table, &c. as little as pos- shell-fish had ever fixed on the copsible, as it is difficult to get off. per, which appeared in the same Sand and water will clean the bot. state as when she left the dock. tles, table, hands, &c, soonest. j . buia Yours, respectfully,. .

The following examples we owe to -q8 279111. sCHAIN, AND TAPE. 1 Bradford, July 18th, 1825.

the kindness of Dr. Traill :- .

The ship Huskisson, belonging to Mr. Horsfall, was lately in dock,

after a voyage to and from DemeFACTS PROVING THE EFFICACY OF

rara, where she lay some weeks, ini 5 ŞIR A. DAVY'S, METHOD OF PRO

a river remarkably favourable to the TECTING THE COPPER OF SHIPS

adhesion of parasitical animals and BY ELECTRO-CHEMICAL ACTION.

weeds; yet, when I examined this (From the Annals of Philosophy.)

vessel, her copper appeared perfectly 1. The Carnebrea Castle, an In- clean, as far as it could be seen, when diaman, belonging to Messrs. Wie she was purposely set by the stera gram, of 650 tons burden, was pro- in unloading, in order to show her teeted last spring by a quantity of copper at the bows as low as possiiron in 'four portions, two on the ble. The Captain stated, that be bow, and two on the stern, equal to fore coming into port, while yet in from 10100th to 1'110th part. She clear water, he had seen her bottom has since made the voyage to India, even to the keel, and it seemed to, and was for some time in the Ganges. him quite clean,. This ship was de.. # She ajjpeared bright and clean fended by two bars of malleable iron during the whole of the voyage out bolted along the sides of her keel by and home; some mud collected on copper fastenings, which covered Her bottom in the Ganges, but im- about 1-90th of the surface of her mediately disappeared when she be- copper. gan to sail"She was put into a dry The Elizabeth, a vessel defended doek about a fortnight ago," and her exactly in the same manner, with bottoin examined by Sir H. Davy metals in the same proportions, had the proprietors, and various other made the same voyage. Both had persons. Every part of her bottom been newly coppered when they last was bright and clean, without a sin. left Liverpool; and the Elizabeth's

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276 SIR H. DAVY'S METHOD OP PROTECTING THE COPPER OF SHIPS. copper appeared equally clean as far preserve the copper from corrothat of the Huskisson when unloaded; sion, that it might be permitted to but as she did not enter a graving run a second voyage to India without dock, we cannot absolutely say whe- being renewed, which can seldom be ther she was quite clean, especially done with perfect safety. The iron as the copper of the Dorothy (about extended from one end of the keel to be mentioned) appeared equally to the other, and was fastened on so, until she was seen in the graving with copper nails with large heads. dock, when the flat part of her bot- The Dorothy, thus defended, sailed tom was found to be quite covered again for Bombay in June, and rewith barnacles. The copper of the turned to Liverpool about a month Huskisson, there is reason to believe, since. She was put into the graving was perfectly clean, as was proved in dock yesterday (May 3), and an exathe next case.

mination of her bottom took place as The ship Dee-A very large ves- soon as the water had left her. sel belonging to my relative, Mr. " The copper appeared no more Sandbach. The ship was newly cop- reduced than at the termination of pered about twelve months ago, and the first voyage. The iron was dià bar of malleable iron, about 7-8ths minished generally about three-quarof an inch thick, and three jinches ters of an inch in breadth, and from broad, was fastened on each side of one quarter to half an inch in thickthe keel by iron spikes. It covered

ness. At the ends of the vessel, for about 1-90th of the surface of her cop

about two or three feet, the iron was per. Since that period she has made much more reduced than at any other two voyages to Demerara, and was, part! It was covered with the usual at the conclusion of the last, put into rust, not at all resembling cast iron, a graving dock, when her copper under similar circumstances. The was found perfectly free from corro- flat of the ship's bottom, from end to sion, and there were scarcely any şub

end, and from six to eight feet in stances adhering to it, except a very breadth, was full of fleshy barnacles few minute barnacles, near the keel

(lepas anatifera) of uncommon length, fore and aft. This ease shows, that and a few of the large hard shell speover defence was not the cause of the cies (bulanus tintinnabulum)." foulness of the bottom of the Tickler,

Noteby Dr. Truill. --Weremarked for both in this vessel and in the Hiis

that the specimens of the lepus anatikisson the proportion of iron to the

e fera were considerably larger on the copper was greater than in that ship.

starboard than on the larboard side The iron spikes employed to fasten

of the ship. On noticing this to the the iron on the keel of the Dee, were

Captain, he informed us that the

con so much corroded, as to endanger the

Iarboard had been the lee side of the

. falling off of the bars; copper nails

vessel, almost constantly during the are, therefore, to be preferred.

passage to Europe, and consequently The Dorothy.--Dr. Traill states,

most deeply immersed in the water that the following particulars of the Dorothy's outfit and return, were these animals not anworthy of notice.

a circumstance in the economy of communicated to him by his intelli. gent friend Mr. Horsfall, one of the owners of the ship, in the beginning of May :

It is evident that in all these last - The Dorothy had been coppered cases, particularly in the ship Doroabout a year, and had made one thy, the proportion of iron has been vovare to Bombay and back to this too large, and the quantity of calcaport, when, in May, 1824, it was de- reous earth on the bottom of this termined to place bars of iron, four ship proves that the electro-negative inches broad, and one inch thick. action has been in excesso along her keel, covering about 1-70th part of the copper, in the expecta- * Sulphuric acid was used to loosen tion that the iron would at least so and detach the shells,

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SIR, -The following is an improve point, a, the beginning of the impul. meot proposed to be made on the sive force, let the bub, B, be then Wedge, exemplified by two experi, drawn back to y, directly over P, a ments, which show how the influence mark to which the oscillatory bob is of this mechanical power may be aug- drawn every time of movement till mented. Considering that it may be the wedge is driven under the n end of of use to those who have occasion to the board as far as the point b on the employ wedges in raising of weights, wedge. 1&e. I shall esteem it a favour if you

NOTE. will give it a place in the Mechanics'

Size of the wedge one inch and Magazine.

three quarters square at its base, d; EXPERIMENT FIRST.

and length, ce, three inches and a

half; width, one inch; weight of bob, Dress On !! Explanation.'

ove pound and three quarters ; distance 2018 is a horizontal plane.

from h to p, 18 inches; weight of 191W a wedge.

board, with weight on it, 10 pounds ; Emn, a board with a weight on it, to length of string, 4 feet. Epress upon the wedge.ini

The bub being let go, it took 73 *K, a check, to keep the board from strokes to drive the wedge three inches; sliding back.

point b coinciding with n, for the first S, a stand, with a bob, B, made to experiment. swing through the curved line, yx.

EXPERIMENT SECOND. Having placed the wedge upder the end of the board, at a convenient dis- .. Curve form of the Wedge. tance, the end, n, first touching the The wedge and position of the other

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278 ON THE ADVANTAGES OF SCIENTIFIC KNOWLEDGR. adjuncts being as before, using the same din brow

a rd tattoo force, the wedge was driven under the ag.3. Protar as respective weight to the distance as

92140 signed in the first trial in only 52 0 M strokes of the bob.

The result of these two experiments suggests some obvious improvements in

- Milo the ordinary shape of the wedge, for, when of a curved form, as in the 95 916

ordw second experiment, it is propelled in

Dziqash o considerably less time. I conceive-[103

1 vody that the length of the wedge, ce, being b99bi

A met xde, the height, or, more concisely, 2911

c

ADD TO ME cdo x ce, when applied to the first in to 90 Ingaga viieb doiden stance, is a constant ratio to the mo

i ! !!n 147 mentum (M) on the end, x, but is in. Now, instead of the common form, creased in the second trial by the radius admit the sides xz and yz, to be curof the curve space on the wedge, now vilinear, then it should seem that a altered, expressed by the initial force wedge so formed will cleave the space, Czd, or R = Czd, by which means the cdz, in less tiine, using the same adpower is gained in point of time,which, 'mitted force, than a wedge of the comby analogy, is as 73 to 52, or, con- mon angled form can possibly do. If,

maisto una heino as appears from the previous experiversely, 7, making about 2-3rds, being

ments and calculation, a curved wedge 1-3rd of power gained per curve.'' will raise a weight sooner, by a given

If the radius of the proposed curva power, than one of the common form, ture were twice the length of the wedge,

it follows, by analogy, that one curved then 22-4, the effective movement; on both sides, like the above, will have because the difference between the a double effect."

I am sir.. te length of the curve, Czd, and diagonal

F line, Cd (first instance), x 4, produces

Your obedient servant,'!!" the same thing; for, by putting 8, the greater lineal space Čzd, and 1, the Fisher's-street, Sandwich Italic

Lib .471 lesser or diagonal Cd, then Min. each experiment, when inversely con- ON THE ADVANTAGES OF SCIENTIFIC sidered.

'KNOWLEDGE; 4.15 10 The improvement which I propose BY MR. ROBERT LEWTHWAITE. 11'02 in the form of the wedge, is to make one side curvilinear, a curve whose

Amongst the great variety of subradius is twice the length of any pro- jects which are presented to the posed wedge; thus, in raising of human eye, there scarcely exists one weights, &c. in less time by the same more interesting and instructive than power, or in the same time by less that which is afforded by the study power, i. e. 1-3rd of time, or 1-9th of of science, especially in tracing the power, will be gained in comparison just and wise laws throughout the with the straight-lined wedge.. :whole course of Nature, and in this

These hints furnish us with another study the mind is not only amused, consideration as to the form of a wedge but inquiry, in many cases, roused, requisite for cleaving of wood, &c.

which, if properly pursued, must which is to have both sides curved, as in the following figure.*

ultimately arrive at that desideratum

which is not only the life of the Explanation.

mind, but, in a measure, the life of ABCD is the bottom of a tree sawn the soul; for what persons are there off at AB.

who can observe the various compoxyz, a wedge, curved on both sides,

sitions and deconipositions which are in the act of cleaving.

continually going on throughout the

whole creation, the various celestial * Our engraver has scarcely done and terrestrial phenomena that are justice to the drawing--the curvilineal continually calling forth our humble figure of the wedge is not sufficiently intellect, and not feel within him a indicated.-Edit.

desire for that knowledge which can

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ON THE ADVANTAGES OF SCIENTIFIC KNOWLEDGE. 279 conduct him through the world with ledge. The advantages which science credit and reputation?

produces to those who are distinThose who, during the whole course guished from the rest of mankind of their lives, have been engaged in by their exalted attaininents, are a close and unvaried pursuit of clear and undisputed—the splendour wealth, and at first, perhaps, wanted of reputation, and not unfrequently opportunity, and afterwards inclina- the real benefits of riches and station. ion, to cultivate their minds, are apt On the cases of such men it is not to despise that knowledge to which my intention to dwell, though I could they are strangers; and the con- point out the varied pleasures they tempt they feel is often rendered enjoy in the pursuit of knowledge, more strong by the various instances whilst new phenomena of the most which daily present themselves, of interesting nature are continually men most famous for their scientific being displayed before them, and researches, being able to amass but delightful reflections are perpetually à small portion of that wealth to occurring, which fill the mind enwhich others have devoted their gaged in this grand and sublime whole attention, and in which their pursuit. The advantages which I whole thoughts have centered.- intend more particularly to dwell on, Foolish, indeed, is the expectation are those which may be possessed that nothing on this earth but wealth by common application, assisted by can produce happiness, for, after common abilities. having enslaved themselves through. First, ---Science is valuable, as it out the whole course of their lives opens to our view and explains the in search of that delusive treasure, hidden secrets of Nature. they find that they are, at the end, Second, — It is valuable, as it as far off as at the commencement affords an entertaining and highly of their career.

useful employment for those leisure But how different with the philoso- moments, which, at times, occur to pher! Instead of his thoughts dwelling the busiest of men. Whoever has on wealth and grandeur, which are compared his mind as it was in the but mere baubles in his sight, he is moments of thoughtless dissipation, employed in contemplating the works when time flew unheeded and undis. of Nature, in which he always finds posed to any useful purpose, with some new phenomenon to account what it was after he had bestowed his for, or some more striking experi. time on the cultivation of science, will, ments to attract his attention; and I think, he sensible of its advantages; in this pursuit he unites happiness no one, indeed, can deny it if they without riches, and instruction with- only allow that the mind will be well out fatigue, whilst those in the pur employed; for it is generally known, suit of wealth 'receive little or no that if a man has not objects to attract instruction in their career, and, at his attention, he will naturally turn the end, are deluded by the false aside to thosc vices which are injurious phantom they have been pursuing to his morals and constitution, and

The gay and the volatile, who, by often pernicious to society. their habits, have rendered them. Science will also be found valuable selves incapable of serious appli- to a man of middle rank, as it concation, turn away from the scicnces tributes more to his real happiness with contempt (as they can only be and tranquillity of mind than the acquired by study), and the neglect greatest wealth, unaccompanied with they are apt to cherish 'is strength- a taste for those truly sublime stuened by the deficiency they observe in dies which have been so long and so the humble philosopher, with regard deservedly admired and patronized to those graces of politeness which by the world, and upon which our they have been taught to consider of finest poets have resounded on their the highest value and importance. tuneful lyres.

To both these characters of inen It is to science we owe the arts it may be useful to see clearly stated and enjoyments of civilized life. the real merits of scientific know. Science is the parent of machinery,

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