404

SIEGE OF GIBRALTAR.

water-engines which they had on board. At length in the afternoon the discharges of their ordnance visibly slackened; and it became apparent that several of the last red-hot balls which had pierced their sides could not be extinguished. Before midnight the Talla Piedra, the strongest of the battering vessels, and the flag-ship, the Pastora, by her side, were in full flames, by the light of which the artillery of the garrison could resume its volleys and direct them with the surest aim. "The rock and neighboring objects," says an eye-witness, "were highly illuminated, forming with the constant flashes of our cannon a mingled scene of sublimity and terror." Six more of the battering ships caught fire, and the question to the French and Spaniards upon them was no longer of victory or conquest but of life. Dismal shrieks were heard in the intervals of firing from the poor wretches who expired in the flames or in the waves and numbers more were seen as they faintly clung to the sides of the burning vessels or floated on pieces of timber from the wrecks. More than sixteen hundred of the enemy are computed to have perished. Much greater still would have been the havoc, but for the humanity of our countrymen— above all, of Captain Curtis, with the sailors of the marine brigade, who no sooner saw the victory decided than they strained every nerve to save the vanquished. By their exertions between three and four hundred men were brought to shore. Eight of the floating batteries were already consuming or consumed; it was hoped to preserve the two that remained as trophies, but unexpectedly the one burst into flames and blew up, and it was deemed requisite, after a survey, to burn the other. Thus did the morrow's sun, instead of still beholding those vast sea towers which had so lately breasted the waves in all their pride, and "instinct with life and motion," shine only upon shattered hulls or stranded fragments from the wrecks. Thus did the Pillars of Hercules, so conspicuous as emblems on the device of the Emperor Charles the Fifth, with their ancient motto, NEC PLUS ULTRA ; and borne by him upon his banners in the wars against King Francis the First, now in British hands baffle and beat back all the endeavors of the heirs "of Charles the Fifth and Francis the First combined!

-LORD MAHON.

Too curious man, why dost thou seek to know
Events, which, good or ill, foreknown, are woe;
Th' all-seeing power that made thee mortal, gave
Thee every thing a mortal state should have;
Foreknowledge only is enjoy'd by heaven;
And, for his peace of mind, to man forbidden:
Wretched were life, if he foreknew his doom;
Even joys foreseen give pleasing hope no room,
And griefs assur'd are felt before they come.

THE USE OF ADVERSITY.

THE world had never taken so full note

Of what thou art, hadst thou not been undone ;
And only thy affliction hath begot

More fame, than thy best fortunes could have done:
For ever by adversity are wrought

The greatest works of admiration;

And all the fair examples of renown,

Out of distress and misery are grown.

-DRY

How could we know that thou couldst have endur'd,
With a reposed cheer, wrong and disgrace;
And with a heart and countenance assur'd,
Have look'd stern Death and horror in the face!
How should we know thy soul had been secur'd,
In honest counsels, and in way unbase;

Hadst thou not stood to show us what thou wert,
By thy affliction that descry'd thy heart!

It is not but the tempest that doth show
The seaman's cunning; but the field that tries
The captain's courage and we come to know
Best what men are, in their worst jeopardies.

GOD'S CARE FOR MAN.

AND is there care in heaven? And is there love
In heavenly spirits to these creatures bace,
That may compassion of their evils move?
There is: else much more wretched were the cace

Of men than beasts. But O'th' exceeding grace
Of highest God, that loves his creatures so,
And all his workes with mercy doth embrace,
That blessed angels he sends to and fro,

-DA

How oft do they with golden pineons cl
The flitting skyes, like flying pursuivant,
Against foule feendes to aide us militant:
They for us fight, they watch and dewly ward,
And their bright squadrons round about us pla
And all for love, and nothing for reward:
O, why should heavenly God to men have such re

MACHINERY.

THE utility of machinery, in its application to consists in the addition which it makes to huma economy of time, and in the conversion of subs rently worthless into valuable products. The f from wind, from water, and from steam are so ma to human power, and the total inanimate force t in Great Britain (including the commercial and ma has been calculated, by Dupin, to be equivalent 20,000,000 laborers. Experiments have shown th necessary to move a stone on the smoothed floor of nearly two-thirds of its weight; on a wooden floor, if soaped, one-sixth; upon rollers on the quarry floor second; upon wood, one-fortieth. At each increas ledge, and on the contrivance of every new tool, h is abridged the man who contrived rollers qui power over brute matter. The next use of mach economy of time, and this is too apparent to requ tion, and may result either from the increase of force, improvement in the contrivance of tools, or from b Instances of the production of valuable substances f less materials are constantly occurring in all the though this may appear to be merely the cons scientific knowledge, yet it is evident that science ca nor could its lessons be made productive by applica out machinery. In the history of every science, w improvements of its machinery, the invention of in to constitute an important part. The chemist, the a the physician, the husbandman, the painter, the sculp only by the application of machinery. Applied scie

its forms, and the fine and useful arts, are the triumphs of the mind, indeed, but gained through the instrumentality of machinery. The difference between a tool and a machine is not capable of very precise distinction, nor is it necessary, in a popular examination of them, to make any distinction. A tool is usually a more simple machine, and generally used by the hand; a machine is a complex tool, a collection of tools, and frequently put in action by inanimate force. All machines are intended either to produce power, or merely to transmit power and execute work. Of the class of mechanical agents by which motion is transmitted,-the lever, the pully, the wedge,-it has been demonstrated that no power is gained by their use, however combined. Whatever force is applied at one part, can only be exerted at some other, diminished by friction and other incidental causes; and whatever is gained in the rapidity of execution, is compensated by the necessity of exerting additional force. These two principles should be constantly borne in mind, and teach us to limit our attempts to things which are possible.

1. Accumulating Power. When the work to be done requires more force for its execution than can be generated in the time necessary for its completion, recourse must be had to some mechanical method of preserving and condensing a part of the power exerted previously to the commencement of the process. This is most frequently accomplished by a fly-wheel, which is a wheel having a heavy rim, so that the greater part of the weight is near the circumference. It requires great power, applied for some time, to set this in rapid motion, and, when moving with considerable velocity, if its force is concentrated on a point, its effects are exceedingly powerful. Another method of accumulating power consists in raising a weight, and then allowing it to fall. A man, with a heavy hammer, may strike repeated blows on a head of a pile without any effect; but a heavy weight, raised by machinery to a greater height, though the blow is less frequently repeated, produces the desired effect.

2. Regulating Power. Uniformity and steadiness in the motion of machinery are essential both to its success and its duration. The governor in the steam-engine is a contrivance for this purpose. A vane or fly of little weight, but large surface, is also used. It revolves rapidly, and soon acquires a

uniform rate, which it cannot much exceed; because any addition to its velocity produces a greater addition to the resistance of the air. This kind of fly is generally used in small pieces of mechanism, and, unlike the heavy fly, it serves to destroy, instead of to preserve, force.

3. Increase of Velocity. Operations requiring a trifling exertion of force may become fatiguing by the rapidity of motion necessary, or a degree of rapidity may be desirable beyond the power of muscular action. Whenever the work itself is light, it becomes necessary to increase the velocity in order to economize time. Thus twisting the fibres of wool by the fingers would be a most tedious operation. In the common spinningwheel, the velocity of the foot is moderate, but, by a simple contrivance, that of the thread is most rapid. A band, passing round a large wheel, and then round a small spindle, effects this change. This contrivance is a common one in machines. 4. Diminution of Velocity. This is commonly required for the purpose of overcoming great resistances with small power. Systems of pullies afford an example of this: in the smokejack, a greater velocity is produced than is required, and it is therefore moderated by transmission through a number of wheels.

5. Spreading the Action of Force exerted for a few minutes over a large Time. This is one of the most common and useful employments of machinery. The half minute which we spend daily in winding up our watches is an exertion of force which, by the aid of a few wheels, is spread over twenty-four hours. A great number of automata, moved by springs, may be classed under this division.

6. Saving Time in natural Operations. The process of tanning consists in combining the tanning principle with every particle of the skin, which, by the ordinary process of soaking it in a solution of tanning matter, requires from six months to two years. By enclosing the solution, with the hide, in a close vessel, and exhausting the air, the pores of the hide being deprived of air, exert a capillary attraction on the tan, which may be aided by pressure, so that the thickest hides may be tanned in six weeks. The operation of bleaching affords another example.

7. Exerting Forces too large for human Power. When the force of large bodies of men or animals is applied, it becomes