scholars. If now there be but few, it is because few can withstand the pain, the fatigue, the wearing down of the constitution which accompany continued mental labor. Why, even the weaving of words and sentences into such a fabric as may not be altogether unfit to be presented among the articles of this exhibition, is harder work, and requires for its execution a longer apprenticeship, than any labor of the hand-loom.

Those profound thinkers who direct their labors immediately to practical purposes, and who do so with success, are sometimes happy enough to secure, at once, the respect and gratitude of their fellow men. Arkwright, the inventor of the spinning-jenny, gave rise to a revolution in manufactures, which has had more influence upon the destinies of the earth, than all the wars of Napoleon. Watt, by bringing to perfection the steam engine, created, and subjected to the service of man, a race of Titans, the obedient and legitimate slaves of his will. Such services are obvious, and are appreciated. But the pursuits of science are by no means always of this character. The philosopher is generally led forward in his investigations, not by any immediate views of practical utility, but by that strong impulse of curiosity, which God has been pleased to implant in a few superior minds, appointed by himself to give light and knowledge to the world.

Now sordid and ignorant men are in the habit of ridiculing these men, and their occupations. When they see the mathematician poring over his symbols, to them more unintelligible than the hieroglyphics of Egypt, when they see the mineralogist collecting stones, and the botanist peering at flowers and weeds by the way side,-when they see a Franklin flying kites, and a Newton blowing soap bubbles, they sneer at the trifling occupations, and superciliously demandcui bono?-what is the use of all this?

Now, the terms good and useful are very difficult to define, and will be differently applied by different persons. For my own part, I would give a high place among the advantages of knowledge, to the pleasure which it is capable of affording us. Pleasure-innocent pleasure-is itself a good, and he who presents us with a new source of pleasure, confers a benefit which may be truly called useful. Even the rigid utilitarian acknowledges this, provided the pleasure be to his own taste, though he may scorn the mere intellectual enjoyments of the philosopher. An example will show this:

Some years ago, Sir David Brewster invented an optical instrument, familiar to you all, called the kaleidoscope. In this contrivance, by means of repeated reflections from two plane mirrors, an object, without regularity or beauty in itself,-made up of broken beads, crooked pins, and the like,-had its image multiplied in the sectors of an entire circle, so as to present a form beautiful from its perfect symmetry. This instrument, capable of presenting such pleasing images, and of varying them to infinity, was in every one's hands, and excited universal delight; and Brewster might boast of having solved the problem of the Roman Emperor, and invented a new pleasure. Yet our satisfaction was continually interrupted by the remark:-well, this is

very pretty, to be sure, but what is its use? At last some Birmingham and Manchester men bethought them of using the instrument to suggest figures for carpets and paper hangings, and our houses were ornamented with kaleidoscope patterns. At once the utilitarian was satisfied, and acknowledged that the kaleidoscope had made itself useful. He did not reflect, that, while the figure on the floor, or the wall, was not half so beautiful as its optical prototype, it was also not a whit more useful: but then he had a taste for domestic ornaments, and none for philosophical experiments.

Investigations having their origin in pure curiosity, and which often reward their projectors only by the pleasure which arises from the discovery of new facts, are, when fully prosecuted, seldom, if ever, barren, in direct applications of practical importance. Such consequences, often very remote, are not, indeed, the inducements which lead the lover of science in his labors. For him, the instinct of curiosity is sufficient. But as practical utility is a test required by the mass of men, I agree, for the moment, to submit the pursuits of the philosopher to this trial; and in the selection of examples, I am embarrassed only by the multitude which press themselves upon my notice.

My first is taken from an old experiment in chemistry. Never, perhaps, was there a man possessed of a more insatiable curiosity than Roger Bacon. He was constantly applying to nature to teach him her secret mysteries, and he interrogated her in the only language to which she will answer-the language of experiment. In his day, the false science of alchemy was in vogue, and thousands of combinations were tried, in order to discover, if possible, some method of forming the precious metals. The research was vain as to its intended object, but not always so as to other practical results. Numerous important facts were observed, which laid the foundation of the true science of chemistry. Among these, Bacon discovered that if charcoal, sulphur, and saltpetre be combined, they form a mixture which explodes by fire: this mixture is gunpowder. The experiment was undoubtedly a curious one; but could any man, at that time, have anticipated its tremendous consequences? Yes: there seems to have been one, and it was Bacon himself. His prophetic mind suggested to him the terrible applications that could be made of his discovery, and he did not dare to take the responsibility of putting such an instrument of mischief into the hands of his fellow men. He concealed his discovery in an enigma, which he terminated by the tantalizing words "et fias tonitru, si scias artificium;"-that is, to give a free translation, "and you may produce thunder, if you can find out my secret." The secret was found out, and the discovery, to which the curiosity of Friar Bacon had led him, produced a revolution in the world. A new power was created which would tear solid rocks asunder. The fleetest animal could not escape the swift messenger of death propelled by gunpowder, and the most savage dared not to contend with it. Weapons wielded by personal strength became insignificant in comparison with the superior force of fire arms; and the whole system of

war, by which the destinies of mankind have been so much governed. was changed.

Many years before the commencement of the Christian Era, some curious observer discovered, that when amber was rubbed, it acquired the property of attracting light bodies to it, and holding them suspended. For ages this remained an insulated and unprolific fact, and the experiment was considered a trifling one by all but those who had learned that no truth is unimportant. At length the experiment was resumed. It was found that many other substances possessed the same property as amber. The apparatus was enlarged, and new phenomena were presented,-light, and heat, and sound being produced. Means were then found for collecting, and, as it were, bottling up the mysterious agent of these phenomena, and effects of the most astonishing kind were presented. In a word, discovery after discovery was made, until the new science of Electricity was offered to the wonder of mankind. The electricity accumulated in large machines, and particularly in the Leyden battery, exhibited appearances and produced effects which seemed to simulate the lightning, though in a feeble degree, and the identity of the two was suspected. Our own Franklin, who had acted a conspicuous part in the science, had a curiosity not to be satisfied by mere speculation, and he determined to test the suspected identity by direct experiment. For this purpose he adopted an expedient characteristic of his mind, which seemed always in a playful mood, even when laying the foundations of a science, or of an empire. He made a common boy's kite; surmounted it by a metallic point, of which he had himself discovered the remarkable electrical properties; depended upon the hempen cord, with a key fastened to the end of it, for his conductor; and insulated the whole by a twine of silk to be held in the hand. Aware of the ridicule which so falsely attaches itself to such pursuits, he went secretly to a common on the skirts of this city, and raised his kite. A promising cloud passed over, and electricity was eagerly sought for in the apparatus, but none appeared; and disappointment and chagrin. threatened our philosopher, when a shower fell, and the wetted cord became a better conductor. The knuckle was again applied to the key; several distinct sparks of electricity were given off, and the great discovery was completed. It was proved that the lightning which charged the clouds, was the same substance as that, which, in the amber and glass, had raised the wonder of the philosopher, and the sneers of the utilitarian. The thrill of pleasure which this experiment excited in the breast of Franklin, was not confined to him alone. The discovery was hailed with enthusiasm over the whole civilized world. And what produced this universal feeling of pleasure? It was the gratification of an intense curiosity. No one could be so dulk as not to desire to know the cause of the terrific phenomenon of the thunder storm, and the Philadelphia experiment told to the world this great secret of nature. Was not this enough? Must some matter of fact man chill the general enthusiasm by his cold inquiry-cui bonowhat's the use? Yes: the inquiry was made, and most triumphantly was it answered; for the discovery met immediately with its practical

application, in the invention of the lightning-rod, that noble contrivance which gives us security amidst the most frightful turmoil of the elements, which robs the lowering thunder cloud of its terrors, and lays the red bolt of Jupiter harmless at our feet. The discovery of Bacon brought weapons from the infernal regions, to carry death. among the ranks of men: the discovery of Franklin disarmed heaven. of its artillery, for their preservation.

If philosophers, in the investigations which they undertake, cannot foresee the practical conclusions to which they are to lead, they have yet too many proofs, such as the above, of the utility of all natural science, to permit them to doubt that their pursuits are to bring about good, as well as gratification. It is the dull and ignorant only, who, utterly incapable of receiving pleasure from the discovery of truth, also doubt, or affect to doubt, its importance. How signally is their scepticism often refuted by the most unexpected results! Of this, let me ask your attention to one other example.

The gases, which are transparent and colorless, present no exterior appearances by which they can be distinguished, and they were accordingly all confounded with atmospheric air. Little was it suspected that they really differed as much from one another in their properties as do the metals, or any other bodies; but at last the investigations of pneumatic chemistry proved this to be the case. Among the experimenters in this department, the earliest after Black, and the most successful of all in the discovery of facts, was the celebrated Priestly. His curiosity on the subject was insatiable, and led him to the most singular researches for its gratification. Among these was the examination of the noisome air which rises from stagnant pools. Methinks I see the supercilious dandy turning away his offended nose and resorting to his pouncet-box, and the coarse groom bursting with unrestrained laughter, as they see the old philosopher raking the mud of a horse-pond, and carefully collecting the gas which bubbles up from the bottom. How absurb an occupation, in the eyes of ignorance! Now mark the discoveries of which this was the first step. The gas is taken to the laboratory. It is found to be inflammable, and to be much lighter than atmospheric air. Analysis proves that it is a compound of hydrogen and coal, and it is named carburetted hydrogen. It is obtained from other sources, and particularly from the distillation of bituminous coal, which yields it in great abundance, and also in greater purity. Thus far curiosity has led the research, and its gratification has been the only reward; but now begin the practical applications.

The gas is found to burn with a bright flame. The happy idea is suggested of using it for lamps instead of oil. The experiment is tried upon a small scale, and is perfectly successful. The scale is boldly extended. Immense laboratories are built; huge gasometers are erected; iron pipes are laid for miles in extent; and to every part of the largest cities there is conveyed a source of light which rivals that of day. The effect is wonderful-is magical; and the utilitarian is forced to acknowledge that it is also most beneficial.

But another application of this gas has been made to a purpose no

less astonishing. Of all the attributes in which other animals excel man, (and they are not a few,) there is perhaps none so much a subject of desire, I may almost say of envy, as the power which the birds possess of flying through the air, while we are confined to the surface of the earth. Accordingly, means of traversing the air have been eagerly sought after in all ages, and the history of inventions furnishes us with numerous records of vain attempts to attain this object. The problem was at last solved, in part at least, by the air-balloon, which consists, as you know, of a large reservoir of silk filled with a gas lighter than the atmospheric air. Now, the gas which we have been considering, possesses this property, and from the ease and economy with which it can be made in large quantities, is the best calculated for this purpose. By its aid man can be transported through the air on silken wings, soar to a height from which he might look down upon the Andes, and return to the earth in perfect safety. He can more than realize the fable of Icarus, and without its fatal termination.

The system of gas-lights, and the air-balloon, are two of the proudest triumphs of science and art. Let me call upon you to look back, from the exhibition which I have made of them, to the picture which I first presented, of a little man in black, curiously engaged in the apparently childish occupation of gathering air bubbles from a stagnant pool. The occupation of Priestly was not childish. He was in search of a jewel more precious than the diamond. He was in search of truth. He found it; and it now occupies a brilliant place in the diadem of jewel truths which crown the memory of a philosopher, to whom Pennsylvania has the honor of having afforded first an asylum from persecution, and then a grave.

I have now laid before you the views which led to the establishment of the Franklin Institute,-have pointed out the means which it employs for carrying these into execution,—and, in doing so, have found it necessary to defend the labor of the mind from the accusations of ease and inutility. We have seen that the great principle which serves, with most assurance, to advance the useful arts, and to improve the condition of man, consists in combining the work of the intellect with the work of the hand; so that what the researches of science have produced as abstract truths, the hands of labor may turn into results of practical advantage. Labor and science, if in singleness, may be regarded, the former as a sturdy bachelor, rejoicing in his thews and sinews,—the latter as a maiden, conspicuous for her beauty and attractions,-but both barren. Joined in the bonds of a holy union, they are prolific of good, and their offspring are individual comfort, plenty, and refinement, and national strength, independence, and prosperity.

And now, ladies and gentlemen, it only remains for us to thank you, as the honored representatives of the Philadelphia public, for the favor by which we have been sustained amidst our arduous though voluntary labors, for the patronage with which our exhibition has been honored and rewarded, and for the kind attention which we have received from you, in this our closing scene.