balance, by teeth of a peculiar form projecting from | ous escapements, into a vibratory motion. But as in a horizontal crown wheel. clocks the pendulum was found to be a most invalsThe lever watch is so named from the lever escape-able adjunct, absorbing, as it were, in its own more ment of Mudge, in which the impulse is given to the or less extended oscillation, every inequality in the balance by a lever attached to anchor pallets.

These are the only other parts of the mechanism of the watch of which it is necessary here to treat.

rotation of the wheel-work, or the vibration of the balance, something of precisely the same nature fir watch escapements was the great desideratum, when the balance-spring or hair-spring was invented: and, from this analogy, it even acquired the name of the pendulum-spring-improperly so, however, as laid remarks, especially as there is a pendulum-spring another description altogether.*

Simple and obvious as the suggestion of the rega lative influence of a spring, applied to the vibrating mechanism of the watch balance in place of esthe weight or pendulum, may now appear, especially ahe the idea of the main-spring, as a substitute for the mais taining weight, had been suggested, this has been held to be a crowning invention in the mechanism of the watch; and the honour of its first suggestion has ben claimed by no less than three very eminent men Dr Hooke, by Abbe Hautefeuille, a Frenchman, by Huygens, the Dutch astronomer. It was ultimately proved, that although Huygens had applied for a pë tent at Paris in 1674, Hautefeuille had done so several years before; while Hooke had made a similar appl cation in England in 1658. To Hooke, therefore, th“ be attributed the first idea of the balance-spring.

In its application to the balan of a watch, one of the extremitie of the spring is fastened to a poi independent of the balance, while t other is attached near its axis.

When the balance is at rest, spring is inclined neither way, position being called the point of t but when the impulse is given to the balance by crown wheel of the escapement, it is clear that new i rotatory motion of the balance cannot take place, evrs though there should be nothing in the form of t escapement to prevent it; the balance will now move round so far as the impulse given is able to orte come the elastic resistance of the spring; d that resistance becomes equal to the impulse given, balance will stop for a moment, and then be drive back by the elastic recoil of the spring, continuing thes to vibrate so long as the impulse is repeated r I watch is in motion.

The recoil of the spring is sufficient to drive had the balance to a distance nearly double the length its first motion; this is therefore called the long are vibration. But when the motion of the balance is f with a certain length of spring, the long are of vin tion is made in less time than the short one, to which the impulse is given; with a spring of greater h this principle is reversed; whence it was concluded Le Roy and Berthoud, that equality of time, or d nism, in unequal vibrations, could be more easily tained by lengthening the spring than by tapering In principle, too, the stronger and shorter the spra the quicker will be its vibrations. Thus, effects da extremely varied description can be produced on the motions of a watch by the slightest difference of l and taper in a hair-spring. And it is thus that correctness of the time-keeping is essentially depen ant on the principle adopted in the formation of apparently most insignificant little appendage. So is this the case, that, if the hair-spring be isochr

* This little instrument, the hair-spring, is no less res

The balance, as may be seen from the representa- for the extreme delicacy of its construction, than for Be tions of it in connexion with the different escapements value which it shows the possibility of giving to a p just noticed, is a wheel finely poised on its axis; the of exceedingly small and insignificant appearance by pivot-holes in which it turns being frequently, in chro- labour. Four thousand hair-springs scarcely weigh ter nometers and clocks, as well as in watches, jewelled, a single ounce, but cost often more than £1000! The or made of small rubies, diamonds, &c., as those of the sculptor," as Mr Thomson justly remarks, "ma other of the wheels also are, for the sake of durability. mense value to a block of marble, and the cam may The natural effect of an impulse given to such a wheel of great price from the labour bestowed, but art effus neuzs would be a complete rotation on its axis. This, how-wherein the cost of the material is so greatly enhanced by bi ever, as we have already seen, is convertible, by vari- | skill as in the balance-spring."

resistance of the balance, allowing the spring no more influence over it now than it had before. The screws are turned in or out, or the place of the sliding weights adjusted, by experiments on the rate of the machine; so that if an increase of temperature causes it to gain time, or a decrease to lose, the screws must be turned outwards, or the weights moved farther from the ends of the arms; if the contrary be the case, then of course the contrary changes must be made.

The compensation curb is another instrument for correcting variations in the rate of going from variations in temperature. It limits or extends the length of movement in the hair-spring itself, by a self-moving action, also caused by a difference in the effect of change of temperature on two different metals, and is called a curb, from the name of a small piece of mechanism which operates similarly on the balance-spring in regulating a watch by hand.

time-keepers be made to measure time with accuracy, | that led Sir Isaac Newton and others to recommend to government the offer of a public reward for the accomplishment of so desirable an object; and it was the hope of reaping the splendid reward of £20,000, which government accordingly did offer, that formed the very main-spring to all those high exertions of horological ingenuity which led to the final success of John Harrison, after an unwearied labour of forty years-a success which, in turn, resulted in the present highly advanced state of horology, the perfection of which, as a most scientific art, is perhaps only paralleled by the perfection of astronomy as a cognate science deeply indebted to it, and indeed to which it is as indispensable, in almost every respect, to the present condition of society.

USEFUL HINTS.

pairing of clocks, while a diversity of talent and exp rience is necessary to qualify him for the manipulata of watches. "The possessor of a good picture wond doubtless inquire into the ability of the artist before he intrusted him to retouch it; and this caution is equally necessary for a watch, as many of the best no struction have sustained irreparable injury from the hands of unskilful workmen. Even bad watches (whe are by far the greatest number) require the aid of better hands than those which constructed them." A clever artist may enable even a bad watch to perform tolerably well. Watches should ordinarily be cleared every second or third year; small, flat, or complicated ones oftener. All require care in handling. Tin should be regularly wound as nearly at the same bour as possible; and while being wound, should be hel steadily in the hand, so as to have no circular mote themselves. When hung up, let the watch have sup port, and be perfectly at rest; or when laid horizontal ), let it be placed on a soft substance for more genera support, otherwise the motion of the balance will gene

For the attainment of habits of punctuality, for the regulation of the usual routine of business and of everyday life, for the morning's timely arousement, and the evening's sufficient repose, and for other and innumer-rate a pendulous motion of the watch, causing mu able purposes of convenience, necessity, and pleasure much, in reality, often depends on the judicious selection of a time-keeper. And even the character of a young man has been known to be much influenced by the quality of his watch, the possessor of an accurate time-keeper becoming ambitious to emulate its excellence, and thus gradually acquiring habits remarkable for punctuality. It is therefore to be regretted-even though in many cases a very indifferent time-keeper may be thought all that is required for general purposes-that no efficient instruction can be given to the inexperienced, especially towards the selection of a watch, as none but a workman possessing the highest knowledge of his art is capable of forming a correct opinion of its relative merits. The hints given by a skilful and practical artist himself, however, who has had years of the most attentive and constant experience, cammot but be deemed invaluable; and as such, we would especially recommend a popular little volume, recently issued by Messrs Boone of New Bond Street, namely, "Thomson's Time and Time-Keepers," for the useful as well as pleasing and interesting instruction, to the inexperienced in horology, with which it is stored. A work such as this is a novelty, opening up the rather abstruse science of horology to the general reader, much in the same way in which the highly popular works of Professor Nichol have opened up the more sublime and still more abstruse science of astronomy.

Amongst many valuable hints for the proper selection of time-keepers contained in Mr Thomson's little volume, we shall take the liberty of briefly instancing the following; and first of clocks :-These, in general, measure time more accurately than watches, especially eight-day weight or long-clocks, which are also cheapest. Long and heavy pendulums are to be preferred. The pendulum should occupy the whole available length of the case, except in regulators, or in pendulums beating seconds. A light pendulum shows a clock to be badly constructed, or deficient in power. Steel rods are better than brass, well-seasoned and varnished wood than steel, and compensation-rods than either. The clock should be steadily fixed to the wall, or firmly placed on three feet sufficiently far apart, so that the mechanism may be uninfluenced by the oscillations of the pendulum. Clocks are regulated by lengthening the pendulum to make them lose, and by shortening it to make them gain; this is very generally done by turning a nut or screw below the weight or bob of the pendulum, to the right to gain, or to the left to lose; or, if the screw is above the weight, the rule is reversed. Many French clocks, and a few old English ones, are liable to derangement in striking, unless the hands are moved rapidly forward. The hands of English clocks, in general, may be turned either way without injury, and the same with a watch, unless it has an alarm. An intelligent careful man may be safely trusted with the cleaning or re

variation in time. Should a watch vary by heat
cold, as when worn or not worn in the pocket, t
hands may be set to time; but the regulator shoe
not be altered, if set to the ordinary temperature of
season. Compensation-watches, if properly constructe
do not so vary. A trial even of a year or two is
proof of the substantial worth of a watch. Dealers
themselves may be deceived. A duplex watch may
very bad, while a vertical one may be very good,
that workmanship is as important as principle. Many
low priced and bad watches have eight or even vs
holes jewelled, while many good and costly ones have
but four: a hole can be jewelled for three shilings
"The high sounding description, the handsome exit
rior, the offered trial, and enticing cheapness, ar
effective baits to the short-sighted." External
ment forms but a small item of expense, and the pries
therefore will, in general, point out the comparat
qualities of the work in the shop of an artist of k
integrity and ability. The large thick old watch is
absurd than some recently made little thicker th
half a crown [or even much smaller, as in the latest
and rarest novelty amongst the beautiful and ingensra
Genevese watches, one of which, recently seen at !--
neva by one of the editors of the present seres
papers, was about the size of a shilling). The her
watch is capable of great accuracy, and is preferabir ?
the vertical, though the principle of the latter is m
generally understood and more easily repaired; leve
watches, however, are neither expensive to repas 2o
liable to derangement. The horizontal or eyinde
watch is liable to great tear and wear, but perkera
with considerable accuracy. The duplex watch, w
a compensation balance, when well constructed, uni
treated with ordinary care, will keep time with L.
greatest accuracy, but being delicate, it does not
violent exercise; a bad duplex watch is most expem
to repair. The detached watch, the escapement
which is the only one used in marine chronometers, a
the most perfect, but requires care. Repeaters are es-
pensive to repair as well as to purchase, but may be u
accurate as others. Watches showing seconds are des
useful, and, if well made, are neither expensive
easily deranged. A watch may be handsome, yet b
but a good watch is seldom unsightly. The spring
shutting the shells is not so good as the snap; iA
allows dust to, penetrate to the works. The covers
hunting-watches will not protect the glass when the
hunters are very flat. The extreme accuracy of
rine chronometers is partly produced by their le
kept constantly in a horizontal position. They are
required to show equal time; whether they gain
lose is of no consequence, provided they are regu
and keep their known rate.

Printed and published by W, and R. Changers, Edlabags
Sold also by W. S. Ona and Co., Lenès.

CHAMBERS'S

INFORMATION FOR THE
THE PEOPLE.

CONDUCTED BY WILLIAM AND ROBERT CHAMBERS, EDITORS OF CHAMBERS'S
EDINBURGH JOURNAL, EDUCATIONAL COURSE, &c.

NEW AND IMPROVED SERIES.

KEY TO THE CALENDAR.

Britain, the general average of the thermometer · month is 37 degrees. Vegetation is nearly at a m during January. Our ancestors thought it new. that it should be a severe month, for the sake rest of the year. This mode of judging, howeve not confirmed by modern experience; for a midv. is often followed by a warm summer. A few flower, the crocus, mezereon, and polyanthus, are ocess seen to blossom in the latter part of January; and a the same time (in England) the hedge-sparrow, and wren, begin to pipe.

21. St Agnes's Day, a festival of the Church of Rome. | to replace it. In the central parts of the island of Gr The annals of canonisation present no image of greater sweetness and purity than St Agnes. She is described as a very young and spotless maid, who suffered martyrdom in the tenth persecution under Dioclesian, in the year 306. A few days after her death, her parents going to make the offerings of affection at her tomb, beheld a vision of angels, amidst which stood their daughter, with a snow-white lamb by her side. She is therefore usually represented with a lamb standing beside her. Perhaps this legend has been partly founded on the resemblance of the name Agnes to Agnus, Latin for a lamb, for jingles of sound often led to more important ideas in the middle ages. At Rome, on St Agnes's Day, during mass, and while the Agnus is saying, two lambs as white as snow, and covered with finery, are brought in and laid upon the altar. Their fleeces are afterwards shorn and converted into palls, which are highly valued.

Throughout the Christian world, and in England as much as elsewhere, it was customary for young women, on St Agnes's Eve, to endeavour to divine who should be their husbands. This was called fasting St Agnes's Fast. The proper rite was to take a row of pins, and pull them out one after another, saying a pater-noster, and sticking one pin in the sleeve. Then, going to rest without food, their dreams were expected to present the image of the future husband. In Keats's poem, entitled "The Eve of St Agnes,” the custom is thus alluded to :

They told her how upon St Agnes' Eve,

Young virgins might have visions of delight,
And soft adorings from their loves receive,
Upon the honied middle of the night,

If ceremonies due they did aright;

As, supperless to bed they must retire,

And couch supine their beauties, lily-white;
Nor look behind, nor sideways, but require

Of heaven with upward eyes for all that they desire.

25.-Sexagesima Sunday; eight weeks before Easter. Conversion of St Paul-A festival of the Romish and English churches, and, in London, a holiday at the public offices, excepting the Excise, Stamps, and Customs. The populace in former times thought this day prophetic as to the weather of the year :

If St Paul's Day be fair and clear,

It doth betide a happy year;

If blustering winds do blow aloft,

Then wars will trouble our realm full oft;
And if it chance to snow and rain,

Then will be dear all sorts of grain.

In Germany, when the day proved foul, the common people used to drag the images of St Paul and St Urban in disgrace to duck them in the river.

30. The Martyrdom of King Charles I.-A holiday of the English Church, in whose behalf Charles is held to have lost his life; observed by the closing of all the public offices, except the Stamps, Excise, and Customs. A motion in the House of Commons in 1772, to repeal as much of the act of 12th Charles II., cap. 30, as relates to the ordering of the 30th of January to be kept as a day of fasting and humiliation, was lost by 125 against 97. The sheet in which the head of Charles was received upon the scaffold, presenting large black stains from his blood, together with his watch, are preserved at Ashburnham Church in the county of Sussex, having been given at the time to his friend Lord Ashburnham. The cap, of laced satin, which he wore on the scaffold, and which he directed to be sent to his friend the Laird of Carmichael in Scotland, passed through the hands of that gentleman's descendants, the Earls of Hyndford, and is now the property of Robert Logan, Esq., residing at New Lanark.

Natural History-January, in our climate, is the coldest month of the year, on an average; for in some years February and March are both colder. The store of heat acquired in summer is now completely dissipated, and the sun has not yet attained sufficient power

FEBRUARY.

The establishment of February as the second eof the year by Numa Pompilius has already been tioned. According to Ovid in his "Fasti," a cr record of Roman customs, all objects which thought to have the effect of moral purgation religious ceremonials of that people were called F Ceremonials of this kind took place at this hence the name of the month. The vanity of At; is said to have been the cause of this month be.. much shortened. The arrangement of Jubes | seems to have contemplated an alternation of of thirty with those of thirty-one days. Anges one of thirty days; but when Augustus gare name, he could not endure that it should be ene shorter class, and therefore gave it an addit at the expense of February, already one of that Our Saxon ancestors called February sprout la the sprouting of the cabbage, still called kale in Se

1. Quinquagesima Sunday; seven weeks! Easter called also Shrove Sunday.

2. Candlemas Day, or the Purification of the -a festival of the Church of Rome, and holiday English Church. It is said to have been fourde. Roman rites in which candles were carried. T

fathers of the church held it in commemoration
attendance of Mary in the Temple, forty days.
their custom on this day to bless candies and Isr
child-birth, as commanded by the law; and
them among the people, by whom they were care
solemn procession. The saying of Simeon respe
the infant Christ in the Temple, that he won'
light to lighten the Gentiles, probably supple
cuse for adopting the candle-bearing procession
heathen, whose external religious practices the f
of the Romish Church made a practice of imitat...
order to take advantage of the habits of the
Apparently, in consequence of the celebration of
purification by candle-bearing, it became customa
women to carry candles with them when, after
birth, they went to be churched. It was to this us
that William the Conqueror referred in his fam
mark on a jest of the king of France. The latter, : -
ing that William seemed too fat and unwieldy t
the field, said, "Methinks the king of England hes
in childbed." "When I am churched," said W
"there will be a thousand lights in France." A
made good his boast.

Candlemas Day is a holiday at the public offices
cepting the Stamps, Excise, and Customs. It
a Grand Day in the Inns of Court, a Gandy Day 2:
two universities, and a Collar Day at St James's,
one of the three great holidays, during the terms
which all legal and official business is suspended.

There is an ancient superstitious notion, univers Europe, that if Candlemas be a sunshiny day, the is not half finished. The Germans say-The h peeps out of his hole on Candlemas Day, and if he snow he walks abroad; if he sees the sun shines draws back again into his hole. It is an ancies tom in Scotland for scholars on this day to mak sents of money to their masters, and to enjoy t holiday.

3. St Blaise's Day-St Blaise, who has the he of a place in the Church of England calendar, was