in so many applications, as to keep the student in constant wonder and delight. By aid of apparatus the operator seems invested with magical or supernatural power. He calls this invisible agent into active life, directs its energy, and controls its force. Now, it appears darting and flaming, sparkling and crackling like the lightning's flash; and now subdued and tame, it rings a chime of bells. Now like an engine of death the birds fall before the mimic gun, charged to destroy; and again, it causes light-footed

figures to dance a merry reel. We fear its force, we wonder at its greatness, and we laugh at the curious freaks it plays. The shattered model of the miniature house, the head of hair in wild disorder, the miser's plate,-the magic picture, all are full of interest and instruction. There are various kinds of electric machines. Instead of the plate, many machines are furnished with a glass cylinder, as a generator. The plate machines

are deemed the best. Machines may be purchased at the Depository, from thirty to one hundred and fifty dollars, exclusive of jars, discharging rod, chains, &c.

VI APPARATUS FOR PNEUMATICS, PHYSIOLOGY, OPTICS, &c. PNEUMATICS.-Many beautiful and interesting experiments may be performed with the air-pump. The elasticity, expansiveness, and compressibility of air, may be illustrated

FIG. 3. WEIGHING AIR.

by this machine. Four of our cuts represent experiments which are made by the air-pump. These experiments demonstrate, clearly and practically, some facts, which to the uneducated would seem paradoxical. Thus, to prove that air is the means by which sound is transmitted, it is only necessary to place a bell under the glass receiver of the machine, and to exhaust the air, or, in other words, to pump it out, and then by a contrivance, as seen in fig. 1, to ring the bell, and no sound will be heard. If the air is returned to the receiver, and the bell struck, its presence is discovered by the ringing. Again, to ascertain the weight of air, if a hollow sphere of copper, and air tight, is placed as seen in fig. 3, at one

end of a delicate balance, under the exhausted receiver, after being weighed in air, the difference of the weight will indicate the weight of the air. Fig. 4 shows that the air offers resistance to falling bodies, and that if the long glass tube have the air removed from within it, on being inverted suddenly, the piece of coin and the feather which it contains, will fall to the other end at the same instant. Figure 5 exhibits a glass receiver. The air exerts a pressure of fifteen pounds to the square inch in all

directions, up as well as down; so that when the air is exhausted from the glass, it presses upward externally to fill the vacuum, and carries with it the suspended weight. These and a great variety of others may be subject of illustration in this interesting department. Apparatus illustrating the principles of Pneumatics, is exceedingly useful, as it teaches that which has a constant application to the business of every-day life.

HYDROSTATICS AND HYDRAULICS.-This department of science may be illustrated by many interesting and instructive experiments. The Water Level exhibits a variety of vessels of different forms and capacities, united at the bottom by an aperture common to all. If water or any other liquid be poured into the funnel-shaped vessel at the end, it will run into each of the others and rise as high in them as in the one into which it was poured, thus demonstrating that a liquid will rise to a common level, without regard to size or

HEAV

WATER LEVEL.

shape of the united vessels which contain it.

PHYSIOLOGY.-In the sciences of Anatomy and Physiology which are taught in all good schools at the present time, anatomical charts and models illustrating the functions of the several parts of the body, or their philosophy in the system, are found necessary. The cuts, 1, 2, and 3, exhibit something of the anatomical structure of the eye, together with the illustration of optical philosophy, as seen in that organ. No. 4 represents the "spectacle instrument." The object of this instrument is to show

the reason why the concave glass is suitable for one eye, under certain conditions, and the convex glass, in different circumstances, is better suited to the necessities of another; or in other words, to show why the boy cannot see with his grandfather's specs. Every school in which these studies are pursued, should be provided with such facilities.

A Maniken or model of the human figure, with the muscles and other parts removable at pleasure, and of the form and color of life, will be found of great use and value in this study. A set of physiological plates, at least, should be in every good school.

presents the effect produced by the lenses of a double microscope. The rays which diverge from the object A, B, are collected by the lens L, M, and form an inverted image at C, D, and so on.

THE MAGIC LANTERN.-There is no instrument of which we know that embraces a wider range of application than the magic lantern. Ingenuity and invention seem to have been almost exhausted in providing its subjects for exhibition. It seems to throw light on every subject. By it, the glories of celestial scenery are made apparent to our astonished vision. Systems and suns, constellations and comets, are made beautiful subjects

MAGIC LANTERN.-FIG. 1.

interior arrangements of a small magic lantern, and the direction of the rays of light. These rays are received upon the concave mirror e, and reflected to the convex condensing lens c, which concentrates a large quantity of light upon the object painted on the glass of the slide inverted at b. The rays from the illuminated object at a are carried divergent through the lens a,, forming an image on the screen at f.

for illustration. An Adam and Eve driven from Paradise; Abraham offering his son; Joseph sold into Egypt; David and Goliah; the flight of the holy family into Egypt; the Prodigal Son,-carry us back to patriarchal days; while the pictures of Venice, Naples, Niagara Falls, and the St. Lawrence, bring us to our own times and places. Botany, with its innumerable specimens of floral beauty; natural history, with its various orders of animal creation-all afford instruction and amusement. The drunkard's progress; the progress of intemperance; and the bad boy's progress,-illustrated by some thirty different representations,-convey moral truths and virtuous lessons. While the lover of the ridiculous finds infinite fun in the comic characters and humorous scenes. Fig. 2 shows the

Fig. 2.

VI. MISCELLANEOUS REMARKS:

CASE OR CLOSET FOR APPARATUS.-It will be seen, by reference to the chapters on the construction of school-houses, that some provision has been made, in every instance for the keeping and preserving of such apparatus as would receive injury by constant exposure in the school-room. Instead of wooden closet-doors, sash-doors with glass, where deemed advisable, might be substituted. The glass should be of good quality. The panes should be of large size, in order to give the most light, and to exclude all particles of dust. The door should be furnished with a good lock, that it might be closed against all intruders. Within, the shelves should be so arranged as to be easily raised or lowered, so as to suit the height of different instruments, and that all the apparatus may be exposed to view, thus adding much to the appearance of the room. Every article should be so placed that it might be easily taken out, and at the same time show to the best advantage. The light, small articles might be hung at the back

of the closet, on small hooks; while the larger and heavier ones should occupy the shelves. There should be a place for everything, and special care should be taken to keep every thing in the place allotted to it. Neatness, order, and convenience will thus be secured.

In those schools where the ordinary closet would not be sufficiently large to accommodate the apparatus, a neat case should be prepared, of the required length and height, made of thoroughly seasoned stuff, and closely joined together. The doors should be made like large sash, and filled with large, strong panes of glass, well put in. Instead of being hung on hinges, the doors should be double, and made to slide like sash, only horizontically instead of vertically. Dust can thus be more effectually prevented from entering and injuring the apparatus. The shelves should be constructed to move up and down at pleasure, like those of a book-case, in order to accommodate large articles, and facilitate their removal at pleasure. One apartment of this case might accommodate the library of the school.

THE USE AND CARE OF APPARATUS.-Some general remarks in relation to the handling of apparatus, may not be inappropriate at the close of this chapter. The teacher should understand his subject thoroughly before he attempts to illustrate it. The object of such illustration is, to teach, to convince and to impress the subject on the mind; if the illustration is not as complete and satisfactory as the apparatus is capable of making it, failure and mortification is the result. Comprehending the subject as clearly as possible, the teacher should practice all the experiments in private, that he may be well prepared when he comes before his school or class. He should try them repeatedly, in order to be perfectly familiar with their operation, and in order to acquire accurate, delicate, and successful manipulation. When about to use the apparatus, it should be thoroughly examined and freed from dust or specks, which it may have contracted since it was last used. When in use, it should be carefully treated and not entrusted to the indiscreet working of thoughtless, careless children. Children should not be permitted to handle, or even to touch any article, except by the express permission of the teacher. Not even a black-board, to say nothing of anything else more liable to accident, injury, and abuse, should be used by the scholars, unless under the eye of the teacher.

A

Sometimes a teacher may find a portion of his apparatus not incomplete working order. Something in the complicated machinery, very trifling, perhaps is wrong. little care, a little management, and study, and a little patience (always a cardinal virtue in a teacher,) will, in most cases, make all right; if not, no bungling careless hand should be permitted to attempt its repair, but it should be put carefully by, that a proper person may be employed to investigate the mischief and apply the remedy.

For the greater security of the property of the school, the article of agreement between the teacher and the board should be so written, as to make the teacher individually responsible for all damage to school furniture, windows, apparatus, &c., caused by his own misuse, carelessness, or neglect. Such a specification would insure interest and attention in those matters, which are so often neglected, because the teacher would have a pecuniary interest in their preservation. No teacher should be employed who would not willingly assume such an obligation.

After the apparatus has been used, it should be carefully examined and immediately put in the case. Every particle of dust, dirt, soot, oil or water which may disfigure, corrode or injure the instrument should be removed. Everything should be put by in complete order; and if thus treated, and occasionally examined when not in use, a case of apparatus will last a long time, and preserve all its excellence and much of its original lustre and beauty.