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LESSONS IN ARCHITECTURE.–VII. magnificence, they loaded every member of it with ornaments

unknown to the Greeks. In the Composite, sometimes called ROMAN ORDERS OF ARCHITECTURE—TUSCAN ORDER-COM.

the Roman order, there was especially a profusion of ornament; POSITE ORDER.

and there was scarcely a moulding which was not loaded with The origin of the Tuscan order of architecture is involved in decorations. When the particular members could receive no obscurity. During the era of the kings of Rome, it appears more ornaments, they had recourse to varying the outlines of that this order was followed in the buildings of the Romans; their edifices (particularly their temples) into every shape that but it originally belonged to the people of Etruria or Tuscany, could be produced by the union of circular and triangular figures. and in that country remains of this order are found which can | Specimens of the Roman style of architecture are to be seen in be traced to a very remote an.

the arch of Titus and the baths tiqnity. The characteristic

of Diocletian; and two magqualities of the Tuscan style

nificent capitals are to be seen were solidity and grandeur,

in the baptistery of Constantine, features in which it resembled

which belonged to some elder the ancient Egyptian architec

edifice whose history is now ture, with less gigantic but

unknown. A representation of more graceful forms. To whom

the Tuscan and Composite orders the Etrurians were indebted

will be given in the next for their style of architecture

lesson. cannot now be determined, or

In the decline of the Roman whether it originated entirely

empire, Constantine the Great with themselves. Some, indeed,

transferred the capital from say that they brought it from

Rome to Byzantium, as Conthe East; but we cannot agree

stantinople was then called, and with those who would deprive it

attempted to make the latter city of all originality, and assert that

rival the former in monumental it was only the ancient Doric

grandeur by erecting immense stripped of its finest features.

public edifices. Here, however, The early Romans, who used

as in Italy, art and science took this style, did not invent it;

a retrograde course, and the for they were mere warriors and

elegant orders invented by the not artists. They adopted from

Greeks rapidly lost their oritime to time the arts of the

ginal purity and simplicity. A nations which they conquered.

new style was then grafted on Hence, first came the Tuscan

Roman art; the capitals lost style, and then the Grecian orders,

their graceful outlines, and to be adopted by the Romans.

assumed cubical forms; the The Temple of Jupiter Capi.

columns were shortened, and tolinas- began by Tarquinius

the entablature no longer posPriscas, and finished by Tar

sessed its regular proportions. quinias Superbus—said to have

This style of architecture was been built by workmen from

called the Byzantine; its ornaEtruria, and the tomb of Por

mentation was no more that of Senna, king of that people, were

Rome. It again approached the splendid early specimens of this

older Greek style, but shorn order ; but no remains of them

of the grandeur and magnifiare to be found. The column

cence of the whole, and of the of Trajan, built about a century

exquisite beauty of its details. after the Christian era, and

The Byzantine style lasted which remains to this day, is

during the period of the Eastern considered to be a remarkable

empire, and to this day it is specimen of the Tuscan column.

employed by the Greeks in their After the introduction of the

buildings. From the combined Grecian orders of architecture

influences of that empire, and into their edifices, the Romans

the memorials which Rome still chiefly employed Greek artists,

preserved, in the first ages of and made no alteration in the

the Christian era, of the finest form of these orders, except

periods of her architecture, a sometimes blending them toge

variety of styles arose, of which ther in the same building. In

the oldest was called the Latin general, they employed the

style, because it was adopted by Corinthian order, as the most

the whole of the Latin Church. elegant; and a modification of

Numerous examples of this this order is attributed to them,

style are to be found in Italy, as the only attempt which they PORCH OF THE ABBEY OF LORSCH, OR LAURISHEIM.

and some in France; such as the made at originality in architec

churches of St. Laurence (withtare. But some are inclined to

out the walls) and St. Agnes, at believe that even this invention was due to some Greek architect. Rome; the ancient baptistery of St. John, at Poitiers, etc. This This new order was called the Composite, because it was, in style, in which may be found all the divisions of an order, was fact, a compound order, made by the union of the Corinthian and preserved entire until the age of Charlemagne, of which the the Ionian orders. The power, the wealth, and the vanity of the cathedral of Aix-la-Chapelle, and the porch of the monastery of Bomans led them to increase the number, the magnitude, and Lorsch, or Laurisheim, a town of Germany in the grand duchy the decorations of their edifices to a degree far beyond those of of Hesse-Darmstadt, are striking proofs. After the reign of Greece. In the theatre of Marcellus, and in the Coliseum, the this emperor, new innovations and a retrograde movement in Doric and the Ionic styles were both introduced; but the the forms of the orders of architecture led to the Romanesa Corinthian style, with its rich ornaments, was most adapted to style, in which all regular proportion was completely abande the tastes of the masters of the world, and as if not left by while in most of the applications of this style the entabl the inventors in a shapo sufficiently expressive of splendour and was altogether omitted. From the Romanesque to the po

VOL. II.

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MECHANICS.—XVII.
OF OF THISD LAW OF MOTION-LAWS OF FALLING

BODIES-47WOOD'S MACHINE.
Es e os nos ::.-

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e ssed In our last lesson we stated and explained the third law of her Le

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than won motion, which teaches that when pressure produces motion in SRS s mas

e s 3 ste spheres body, the momentum generated in a unit of time is pro* U I

T
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a spinnes of life, portional to the pressure. We deferred, however, the proof Seres

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r essei, and whose of it, and therefore proceed not to r s are

missatsiness of others. I look at some experiments which sbor
2

u ber veri for infidelity ; its truth.
w
ram
a tion to religion. The apparatus usually emplored

y eripuoged B
-

22 i urking of daily life as consists of what is known, after its
e S a m '. V. Sanot consent to confine inventor, as Atwood's machine. I
2 2

2 * : it is essentially applic consists essentially of a fine oord,
De
B o

r who sets contrary to it. which passes over a wheel or unler. S

sv mr Jituf, & convincing proof that and to each end of which eanal is sure

tolerate errors of conduct | weights are fastened. ..

. DA Q. rus ought not so to be, for faith In Fig. 96, A represents the wheel

s e ai n she life are certainly as obnoxious over which the cord passes, & small
Na
s 2
the creed.

groove being turned on the edge to
-
en vrou when seen in the lower creation.

receive it. In order to reduce friction, m. i

have to proved faithful unto death. The which would materially interfere with du si dut the loss of its mate, and the dog | the accuracy of the results obtained.

to plange into the wild surf of the Esse meni drar vaga to plunge into the wild surf of the this wheel does not turn in bearings,

Vestersha Geroost attacks of robber-bands, to but its axlo rests upon the rims of

20 How much more beautiful, however, is four others, called friction wheels. c

i ld in moral and responsible beings; in the These turn with the axle, and so far el is waapa miafortune cannot change; in the love diminish friction that its effect is w w ww ume cannot weaken and oceans cannot scarcely noticed. One of the pillars

ima wafany do principle which temptations to emolu. | which support these wheels is accuHome

*** (Nuno shake, and in respect for the just | rately graduated to inches and iracJamewherewhich no amount of self-seeking can set aside. | tions of an inch.

W'R W er han med however, imply absence of alteration in A hollow ring, D, and a stage or imtime w wwuol. So far from this, fidelity to conviction table, E, are also fixed to clamps

Fig. 96. mar M ateo # markod alteration of our course, and a sliding on this pillar, so that by

sliding on this pillar www ind wantou Now light is ever being cast upon | means of small thomh

means of small thumb-screws they can be adjusted at any height Am

ludividual life; and no man, unless he is either and distance from each other that may be desired. bild i wil, will affirm that it is impossible for him to A pendulum of such a length as to tick seconds, with a small

u nd uthorwise than he does at the then present time. | dial to register the number, is fixed on another support at I. e inde muuta sonson may indeed be most painful to us; it | A catch is also fixed above D to hold w till it is allowed to mi motiu old companionships, and take from us their fall. There are several minor details of construction which

de la Hut nothing can make amends for the loss of have to be attended to, but they need not be explained here. i ... watah fidelity to the present truth brings to every! Since w and w' are equal they will balance each other, and

no motion will ensue; but if we now take a small bar of metal, Tum , euinfined to great occasions or lofty matters ; | F, and lay it across the top of w, it will cause it to overbalance

in m e ty #JIROCO of fidelity in small affairs that we w', and to descend with an accelerating velocity until it reaches

... wir while or wishful to do our duty in matters of the ring D, when, the bar being too long to pass through, will W i el. Fidelity is a matter of heart and conscience.

rest upon it, and w will continue to travel onwards with the Heren of mere detail. It is the spirit of life itself, momentum it has acquired. Now the weight moved is clearly il pre invendud any one department of mundane affairs. the sum of the weights of w, w', and F, and the moving force Hindeboard that fidelity may often hinder material prog. is the weight of F; and by a series of experiments it is found

ille t ve Hindi, and that it may bring anxiety and pain to that the velocity with which w descends is always in the proporlo lile from the certain to more than compensate for all tion of the weight of F, divided by the total weight moved. For Lil l y the great gain of a present easy conscience, and instance, make w and w' each to weigh 71 oz., and F a quarter of med

ured name. It would be invidious to draw an ounce: the velocity will be represented by t, the mass moved Hull Widt bay that women are, on the whole, more being 16 oz., or 64 times the moving force. Now diminish each

n to Hindi but it cannot be forgotten that, in the of the weights to 7 oz., and make F half an ounce. The mass e n durance and the persistency of devotion, they moved will remain the same as before, but the moving force W e of the noblest examples of fidelity in every age will be as large again as it was, and we shall find the velocity RE

will be represented by , that is, it will be twice as great as it Loa, who would succeed in life—in commercial enter. was. In other words, if the mass remain the same, a double

professional duties--will find fidelity a kind pressure is required to produce a double velocity, a triple pressur parently a stern one. Pupils from this school take three times the velocity, and so on.

places in our merchants' counting-houses, rise to Now let the mass be doubled, the moving force remaining places of emolument, and win the highest prizes of the same. Make w and w' 15) oz. each, and F half an ounce, the

velocity will now bed, or the same as it was at first. So that, plies to manifold aflairs; to family confidences, to if the mass be doubled, a double pressure is required to produce waterprises, to religions principles, to social affec- the same velocity. We see, then, that whether the mass or public duties and the secret of many disasters the velocity be increased, the pressure must be increased in the

iduals is to be found in unfaithfulness. same proportion, and therefore that the pressure is proportional

Ich by outward position as by inward to the mass multiplied by the velocity, i.e., to the momentum,
moral principle has its sphere of and this is what the third law of motion asserts.
Lupensed with without endangering
7. Faithfulness has its prominent

MOTION OF FALLING BODIES.
vorner-stones of the temple, and woe We are now in a position to examine the laws of motion of
foundations, or removes it from its falling bodies. At first sight, however, this appears a difficuls

matter, since different bodies fall with different degrees of

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velocity. If we take a stone and a piece of thin paper, and little way under w, and, by shifting it up and down, ascertain let them fall at the same time, the stone will reach the ground the place at which the second tick of the pendulum occurs at before the paper. Most people would say the reason was that exactly the same time as the sound of the bar striking on the ring. the stone was heavier than the paper, but this clearly is not the This distance will be found to be 3 inches. Of course, you must true reason, for if we take two stones of different weights and let measure from the height of the under side of the bar, for that is them fall, both will take the same time. The fact is, that they the part which strikes the ring. This, then, is the space passed are not falling through an empty space, but through the air, and over in the first second, and if we multiply this by 64, we find this offers a resistance to their fall, which increases with the sur-that 16 feet is the space a body, left free, will by its own weight face they present. If we take a piece of gold, and letting it fall fall through in the first second. More exact experiments show from any height, notice how long it takes to reach the ground, that the amount is 161 feet, but we may take 16 as near enough and then beat it out into a thin leaf, its weight will not be for most practical purposes. We have thus found the distance at all diminished, yet it will fall with much

W passes in one second; but we want to know what momentum less speed on account of its increase of sur.

it has acquired, that is, what space it would, from the velocity face. The most conclusive proof that this is

it has received, pass over in the next second, supposing gravity the real reason is afforded by what is called

were to cease to act altogether. As it falls with an accelerating the guinea and feather experiment, as shown

velocity, it must be moving more quickly at the end of the in Fig. 97.

second than at the beginning, and thus its velocity at the end A brass cap is made to fit air-tight on to

must be greater than 3 inches. To ascertain this we leave the the top of a tall glass cylinder, from which

ring as before, 3 inches under the bar. Now when w passes the air can be exhausted by an air-pump.

through the ring, the bar rests on it, being too long to pass, Through this cap a small rod passes, by

and therefore w falls from its own momentum alone. If, then, turning which two small flaps can be allowed

we fix the shelf, E, at such a distance under d that the weight to fall. Now let a guinea or other piece of

strikes upon it at the third tick, the distance between D and 1 money be laid on one and a feather on the

will be that which w passes over from its momentum, and this other. If the rod be turned both will fall,

space we shall find to be 6 inches, or just double that passed but the gold will outstrip the feather and

over in the first second. reach the ground first, because it meets with

Now if the ring had been removed, and the bar left on during less resistance in proportion to its weight. Fig. 97. this second, it would, by the second law of motion, have caused Now replace the guinea and the feather

w to fall through an additional 3 inches. It ought then to fall on the flaps, as at first, but this time carefully exhaust the air through 6 inches from its own momentum, and 3 inches from from the receiver; on turning the rod and watching, both will the force of gravity, making in all 9 inches, and if we place the be found to fall in exactly the same time.

stage 12 inches below the catch, we shall find that such is the All bodies, then, fall at the same rate, and acquire the same case. Thus it passes 3 inches in the first second, and 3 times Felocity in falling, except so far as they are impeded by other 3 inches, or 9 inches, in the second. By again arranging the canses.

shelf and ring, we shall find that the momentum acquired after A balloon, if we could make it strong enough not to burst, two seconds is double that acquired after one, for it will carry Fould in a vacuum fall in exactly the same time as a ball of w through 12 inches in the third second. lead.

Similarly in this second it will move 12 inches from momenIf we take a number of balls made of different substances tum, and 3 inches from gravity, making in all 15 inches, or 5 and arrange them side by side in a box, the bottom of which times 3, and its momentum at the end will be 18 inches. turns on a hinge, and allow it to fly open, the balls will travel | Now if we arrange these results in a tabular form, we shall in a straight line and all reach the ground together. A little find some simple laws which regulate them. Instead, however, consideration shows that it is very natural that it should be so. of putting down 3, 6, 9, etc., we will use 1, 2, 3. The proIf we have a number of equal balls, made, for instance, of lead, portion is just the same, and if we had made the bar instead each will fall in the same time. Now let two or more be rolled of 1 of the mass, these are the distances in feet which would into one, and the large one will fall in the same time that the have been moved over. small ones composing it did, though it is heavier, for there is obviously no reason why the mere change of shape should alter

Seconds.
Space passed over

Velocity at end.

Total space passed over the speed.

in the second.

aed, to end of second. We want to know now what is the actual velocity with which 2 body falls; and this is often a useful thing to know, for by it

1=12 we can ascertain the height of a tower or the depth of a well.

= 22 We have only to drop a stone from the top, and notice how long it takes to reach the bottom, and from this we can calculate the

25 = 52 height.

36 = 62 A falling body is acted on by the attraction of the earth. Now after any given time—say, for instance, one second—it has We see, thus, that the velocity increases in the exact proportion acquired a certain velocity with which it would continue to of the number of seconds the body has been falling; that the move if the attraction ceased. It does not cease, however, and spaces passed over in succes- sen

Seconds hence the body must fall with a constantly increasing velocity. sive seconds are proportional

This we can calculate by means of Atwood's machine. We to the successive odd num. 1. can, by diminishing the weight of the bar, decrease the velocity bers; and that the total space in any proportion we like, and thus are able to measure the fallen throngh in any number Epace passed over.

of seconds is proportional to If the bar weighs as much as the weights do, then the moving the square of that number. force is one-half of the mass moved, and the velocity with which Now we saw that the space it descends is one-half of the velocity it would have were it free any body falls through in the to fall from its own weight alone. But to make the speed more first second is 16 feet. Hence

16 easily measurable, let us further diminish the weight of the bar in the second it is 48, or 16 x 3, as compared with the weights. If we make w and w' to weigh in the third 80, or 16 x 5. 7 oz. each, and the bar, F, oz., we shall have as convenient a Generally, then, if we multiproportion as we well. can. The total mass moved will in this ply the numbers in the above case be 1 pound, and the moving force oz., ord of the mass; table by 16, we shall have those

Fig. 98. the velocity with which w falls will therefore be 4 of that of applicable to the case of fall. a falling body.

ing bodies. This may be more clearly represented by Fig. 98. Now raise w with the bar on it to the catch, and allowing it In this diagram vertical height represents the time in seconds; to start at one tick of the pendulum, note how far it falls before breadth, the velocity; and area the total space passethe next. The easiest way of doing this is to fix the ring a At the end of the first second it shows the space s

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