In the winter season, an opening into the upper part of the chimney, when the draft is good, will answer the purpose. Where this is wanting, and especially in rooms where lights are used, a very excellent means of ventilation is found in an artificial chimney, formed by a pipe issuing from the upper part of the room, with a large funnel at the opening, in which a lamp is kept burning. By means of the strong draft here produced, Sir Humphrey Davy, the celebrated English chemist, cleared his laboratory in a very short time, after having filled it with noxious gases.

But it is not less necessary to guard against the effects of the carbonic acid, which settles in the lower part of the room. In caverns and wells, it often rises only to a certain height; so that above this level an individual may breathe and a light may burn, perfectly well; while a light would be extinguished and respiration obstructed, or stopped, on descending below it. Thus, in the celebrated Grotto del Cane in Italy, in which this gas issues from a cave, and although it is invisible, can be found by its effects to flow along the ground a dog will die, while a man whose mouth is elevated above the level of the gas, suffers no inconvenience. The teacher, therefore, especially if he is elevated on a platform, will not always be sure that the air of that part of the room in which the smaller children are breathing is good, merely because he perceives no want of purity in that which surrounds him; and, like the man in the Grotto, may be surprised to find that one who breathes below him suffers from the badness of air. On this account, it is of great importance that no part of the room should be below the level of the doors; and that regular provision should be made for opening the doors frequently, and for a sufficient time, to allow this deleterious gas to flow off. These circumstances seem to me very decisive arguments against making a school-room descend, as I have sometimes seen, towards the centre, producing a kind of 'black hole' for the smaller children; and they show the importance of employing rooms above the level of the ground, for schools, as well as other assemblies of people. The immediate evil effects are imperceptible perhaps; but seeds of disease and debility may be planted, which no subsequent care can eradicate. The best mode of securing regular ventilation as well as uniform heat in a school-room, during the season when the windows must be closed, undoubtedly is, to introduce the external air from the side, and not from the cellar of the building, through a stove or furnace, so that it may enter the room warm, diffuse the heat equally throughout, and prevent the current of cold air which presses in at every crevice. In this way also, the doors and windows may be opened at any time, without cooling the room too much, as the air usually presses outward.*

* Several excellent plans have been discovered for this purpose, of which I trust the Committee will furnish some account. I have found, that a common stovė might be made to answer the same purpose, in some degree, in the following way: Let a close case of sheet-iron be made of such dimensions as to rise from the

The facts and principles presented in this paper, have been collected with care, from the best and most recent authorities in Chem. istry and Physiology within my reach ;* in the hope that they might serve to impress more deeply on the minds of parents, and of the guardians and visitors of our schools, the importance of providing the indispensable means of bodily health and intellectual vigor, for teachers and their pupils. It can scarcely admit of a doubt, that the premature decay, or sudden destruction of many a faithful teacher, and the debility of constitution of many a pupil, is brought on by the insidious but poisonous influence of the corrupt air in which they spend their days. The economy, which hazards such results, by providing small school-rooms, can only be compared to that infatuated avarice, which destroys life in striving to obtain or to hoard the means of existence. In no single mode, probably, could the American Institute be more useful, than in establishing and circulating correct views on this important subject; and I cannot but hope that their efforts will be the means of extensive good, on this and many other subjects of vital importance to the interests of education, and therefore, to the prosperity of our country.

I am, Gentlemen,
Respectfully yours,

WILLIAM C. Woodbridge.

ART. VIII. PRACTICAL LESSONS IN GEOLOGY.-DIALOGUE IV.

FATHER, I have just found something new. I saw some men putting down large, flat stones, for the side walks, that glittered in the sun like mica, and I took a little piece that was knocked off: what is it?

That which glitters on the outside is mica. But look at the edge of it: can you see nothing else?

Yes, father, I see grains; some of them like quartz, snd some white.

floor to the top of the stove, or a little above it, on three sides; and so large that there will be a space of two inches on all sides between the stove and the case. The stove should be raised on legs, or bricks, a few inches from the floor, and the opening beneath closed in front with brick the other three sides being closed by the case. Introduce the air from without, by a wooden trough, and let it rise under the bottom of the stove, and it will pass out between the stove and its case in a pleasant state of warmth. The trough should be furnished with a slide, to regulate the amount of air, according to the warmth of the stove and of the room; and the case should be so constructed that it may be removed, in order to clean the space around the stove when necessary. The steam stove of Fessenden, maintains a far more equable and pleasant heat than those usually employed, and the same arrangements might be made for ventilation with this, even more successfully. Dampers should be used with great care; they often fill the room with noxious air.

Among these are Hare's, Gorham's, Henry's, and Silliman's Chemistry; Richerand's Magendie's and Bostock's Physiology; Londe's Hygiene; the Paris Dictionary of Medical Sciences, and Rees' Cyclopedia.

Well, my son, those are quartz and feldspar; so that we have all the letters of the alphabet that make granite. But is it granite?

It does not look like it, because it is all in layers · a layer of mica, and then a layer of the grains, and then a layer of mica. And then it splits into large, flat pieces; and granite will not.

You have told the difference, my son. It is just like granite, except that the parts are in layers. It is called gneiss, a German word, pronounced nice. Sometimes you will find nothing but mica and quartz, and then it is called mica slate. But do you see any use in having it in layers? O yes, father; it makes beautiful flat stones for walks; and I remember, the floor of my uncle's cellar is covered with it. I do not believe they could use granite so.

It is difficult to make it so thin. Observe, my son, as you go on, how we find something made for every use; and do not forget HIM that made them all.

DIALOGUE V.

Here is another piece of stone, father, that I found where they were putting up some pillars, that looks just like granite; but there is something black and shining in it, besides the mica.

Scratch it with your steel, and see what color it is.

I see, it is a dark green; but it looks black, at first.

It does; but if you pound it with another stone, you will find that it breaks green. Here is a large piece of it alone.

Why, father, it is so tough I can hardly break it.

Well, now tell me what are the qualities you have found.

It is green, and shining, and tough, but it can be scratched with steel. You are right, my son, and it is the fourth letter of the alphabet in geology. It is called hornblende; horn, probably, for its toughness. It is found in the Egyptian granite; and I suppose gives it greater toughness and durability. Sometimes, too, we find rocks of hornblende alone. Is this called granite, that has hornblende in it?

It is among builders, but geologists call it syenite, another word in geology. A great deal of the granite used in building, is properly, syenite.

But here is another word in geology, formed of hornblende mixed with feldspar. Do you see the white and green, mixed together, and the shining spots when you turn it?

Yes, father; what is it called?

It is sometimes called greenstone, and sometimes trap, from a Swedish word trappa, that means stair; and when it is very fine and close grained, so that it seems all black alike, it is called basalt.

Why, father, I have read about the Giant's Causeway, in Ireland, made of basalt. Is that the same?

Yes, my son; what do you know about that?

Why, sir, my geography says, that it is all in pieces like pillars; and it looks in the picture as if it had been cut into pieces.

That is true, my son. All the greenstone rocks break somewhat in the same way, and seem like a great many pillars of five or six sides set up together. The Palisado Rocks on the Hudson river, and the rocks near New Haven, in Connecticut, and in many other places in our country, look just so.

T'HERE are some plans for economy in education, which, so far as we have known, have not received the proper attention in works on this subject.

The first plan may be styled kitchen education. The first point to be secured is, that the poor should not be well educated; because this would make them worth more, and make their wages too high for domestics. This being done, the improved plan will secure cheap education, and save all the trouble which would otherwise devolve upon the parents, by consigning this charge to domestics. When they are very young, there must be a nurse, of course, who often knows better than the mother how to manage children. If they are left entirely to her care, they become attached to her, so that they do not trouble their parents by hanging about them, or crying when they are going away. But the principal economy is, when they are five or six years old, and require watching and whipping to keep them out of mischief. The domestics can do all this, while they attend to their work; and this saves the parent's time. In addition to this, they become well acquainted with all domestic matters, by inspection; they can hear a great many stories and learn a great many words, which they could never hear from their parents or friends. They learn about the world, especially about all the domestics in the neighborhood; and sometimes hear what troublesome, disagreeable people their parents are; and how foolish it is to do what they order.'

It

But the plan of street education is still more economical and useful. saves all the time of the domestics as well as of the parents. It makes a child still better acquainted with the world, especially in a city. Before he is eight years old, he will learn more of it, from the people that pass along, including ragmen, sawyers, beggars and truants, &c, than his father ever knew, if he was educated in the country. He will acquire from the boys in the street, a variety of ingenious tricks, and many habits which no instruction at home would ever have given him. He will learn a language, too, that will make him at home, in any forecastle, or cellar, or jail, in the country. It happens frequently that a boy will acquire the art of swearing in the most polite manner, before he is six years old, although his father only gives him sufficient examples at home to encourage it. And then, it takes away all the silly shamefacedness of a child. It will teach him the best mode of making his way through the world alone; especially if he is led away by other ingenious boys, and taught how to make excuses; and occasionally fights them.' But the best recommendation is, that it costs nothing either in time or trouble, or money; and it will require no reading, no thought, and no anxiety. In consequence of the immense saving in all these respects, it has already been more generally adopted by parents, than any other of the modern improvements in education.

INTELLIGENCE.

MANUAL LABOR SEMINARY AT Lexington, Mass.

THIS Institution is to go into operation November 4th, 1833. The design of the seminary is, by means of a mechanic's shop and a garden, to furnish healthful and profitable exercise to all who desire it, in connection

with instruction, illustrated with a complete set of Apparatus, in all the branches usually taught in our highest Academies.

MANUAL LABOR SCHOOL IN AFRICA.

We are happy to learn from the Liberia Herald, that Mr Savage, an agent for some emigrants who recently went out from New Orleans to Liberia, contemplates the establishment of a Manual Labor school in the colony. His present residence is at Millburg; and it is not unlikely that the citizens of that place may have the honor of putting into successful operation the first Manual Labor school in Africa.

A free school for recaptured Africans has been in successful operation at Liberia for some time, under the care of Rev. James Eden. No means can probably hasten more rapidly the progress of civilization in that region.

MASSACHUSETTS FREE SCHOOL IN LIBERIA.

The people of Liberia appear highly gratified with the efforts which have been made by some of their friends in Massachusetts, to promote the cause of education among them, and to establish a free school on the basis of the free schools of Massachusetts; and they point to several places where such a school might be successfully located.

PARLIAMENTARY AID TO THE CAUSE OF EDUCATION IN ENGLAND. The sum of £20,000 has been voted by the House of Commons for the promotion of education throughout England - the first parliamentary assistance if not the first parliamentary encouragement which has been given to Education in England for a great number of years. The money is to be placed at the disposal of the National and Lancasterian School Societies, to assist the establishment of schools in those places where, with a little aid at the commencement, they may be maintained by the voluntary contributions of the inhabitants. New York Adv.

This is doing very well for England; but the sum is rather small to be distributed among 12,000,000 of people. The little state of Connecticut alone, with scarcely more than a quarter of a million of inhabitants, devotes nearly an equal sum to her schools, from the public treasury. We think England has begun in the right manner, however, for it should be the great object of all government movements of this sort to help the people to help themselves; and whenever legislative aid fails of this tendency, we may conclude at once, that it is misapplied.

BEQUEST TO TEACHERS.

We learn from a London paper that Mr Dick, late of Scotland, left a large bequest, the interest of which was to be divided among the parish schoolmasters in Marayshire. A dividend of the accumulated interest was made about the end of August last, and each teacher received about 100 pounds sterling.

YOUNG LADIES' INSTITUTE AT TAMPICO.

An Institute for Young Ladies has been established at Tampico, in Mexico, by a lady from the College of the Legion of Honor, in Paris.