Glenwood School-house is situated on Ridge-road, and is intended for an Unclassified school. The building is 66 by 46 feet, besides the projection, and is two stories high. Each story is divided into two apartments, separated by a glazed partition.

Fig. 2.-PLAN OF FIRST FLOOR.

PLANS AND DESCRIPTION OF THE CENTRAL HIGH SCHOOL,
PHILADELPHIA.

In 1853, a new building was erected for the accommodation of the Central High School, in Spring Garden, on the east side of Broad street. The lot is one hundred and fifty feet on Broad street, by ninety-five feet deep, having Green street for a boundary on the north, and Brandywine street on the south.

The building is constructed throughout in a substantial manner, with good materials, and with a main reference to utility rather than ornament, although the latter has not been altogether lost sight of. The walls throughout are built hollow, to prevent dampness; the outside walls and those on each side of the transverse hall have an average thickness of eighteen inches, while those separating the various class rooms have a thickness of thirteen inches. The exterior is built of the best quality of pressed brick. The plainness of the extended façade is relieved by projections and recesses in the line of the outer wall, by a horizontal line of marble work separating the first story from those above, by a large main entrance in the middle, by the cornice, and by the dome of the observatory above. Though simple in design, and constructed in an economical manner, the building presents externally quite an ornamented appearance.

The observatory is built upon two piers of solid masonry. These piers stand isolated from all the rest of the structure, being inclosed within the walls on each side of the front entrance. They are sixteen feet wide by two and a half feet thick, and extend upwards, without material change, from below the foundation to the top of the third story. There they are connected by iron girders, and on these girders the instruments rest. The dome of the observatory rests upon the other walls of the building, and has no connection with the piers that are used to support the instruments. The height of the dome above the level of the pavement, is one hundred and twelve feet.

Throughout the building, careful provision has been made for light. The win

dows are all large, and are as closely placed as a due regard to the strength of the walls would permit. Four out of six of the class rooms on each floor, are corner rooms, admitting light from two sides. The large lecture room on the first floor, is lighted on three sides.

There are two main stairways, one at each end of the large hall. That in front runs in a well, from the first floor to the arch of the observatory. That in the rear connects only the first and second stories. The building has also a double flight of stairs in the rear, connecting the main hall with the basement, a double flight of outside stairs into the basement from each end of the building, and a small stairway connecting the chemical laboratory with the class room above. The main stairways are all six feet wide, each stair having a rise of seven, and a tread of twelve inches. The door into the main entrance in front, is a foldingdoor, opening outwards, eight feet wide and eighteen feet high. That in the rear is also folding, opening outwards, eight feet wide and fourteen feet high. The main entrance into the lecture room is likewise a double door, seven feet wide, opening, freely both ways. The class rooms are all severally connected by doors, with each other, as well as with the main hall. These doors are all three and a half feet wide. The building thus has admirable facilities for the movements of the classes, as well as for being instantly cleared in case of panic.

The general plan of the building is exceeding simple. It is in shape an oblong parallelogram, fronting lengthwise on Broad street, being one hundred feet long by seventy-two deep. There are three stories besides the basement. The plan in each story is nearly the same. A hall, sixteen feet wide, runs east and west, dividing the building on each floor into two equal parts; these parts are again severally subdivided by walls running north and south, into three rooms, averaging thirty-eight feet by twenty-two. This gives six rooms on a floor, except on the first floor, where the whole of the north side is reserved for a lecture-room. There is also an additional small room in the third story, occupying the space in the hall over the rear stairway. The lecture room on the first floor is sixty-eight feet long by thirty-eight feet wide, and twenty feet high, and is capable of seating eight hundred persons.

The height of the several stories, in the clear both of the floor and the ceiling, is as follows: the basement story ten feet; the first story twenty feet three inches; the second story sixteen feet six inches; the third story sixteen feet. The basement in front is five feet three inches above the level of the curbstone; and, as the lot descends considerably in the rear, the basement is, on an average, more than one-half above ground. It is divided into six rooms, with a transverse hall, on the same plan as the stories above, the rooms being intended for a chemical laboratory, clothes room, wash room, storage, &c.

In regard to the important matter of heating and ventilation, two methods engaged the attention of the controllers. The first was, to generate all the heat in one large chamber in the center, and send it thence, north and south, to the ends of the building. The objection to this plan was the difficulty of producing, in connection with it, a proper ventilation. To secure good ventilation in an apartment, it is necessary to establish a current through it. The air must be brought in at one end and carried out at the other end. The ventiducts for carrying off the air, after it has been used, must be, as nearly as possible, opposite to the warm flues by which the pure air is introduced; consequently, if the hot air chamber were placed in the centre of the building, the ventiducts would have to be in the extreme ends. But the end walls, in a building standing apart from others, and en

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Fig. 3.-FIRST FLOOR.

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Fig. 4. SECOND AND THIRD FLOOR.

tirely exposed to the exsernal atmosphere, are naturally colder than those in the center; they would consequently chill the ventiduets, and thereby greatly impair their efficiency in carrying off the foul air.

Besides this, in order that the ventiduets may be perfectly reliable in all weathers, it is necessary that some artificial means should be used for increasing the current by rarefying the air within them. This is ordinarily done by introducing, within the ventiduet, a jet of burning gas, or a small stove. The trouble and expense of such an apparatus is greatly increased by multiplying the number of places where it must be applied. It was, therefore, very desirable, that the ventiducts should be all brought together into one general tube before going out of the roof. One good fire maintained within it would then suffice for the whole building. But this arrangement would be impracticable if the warm-air flues were to radiate from the center, and the ventiducts be placed at the extremities.

It was, therefore, determined to take the other method, namely, to centralize the ventilating apparatus, and generate the heat at the extremities. This is done by four of the largest size furnaces, two being placed at each end of the building, and the heat sent inwards towards the center. This is indicated by the position of the hot air flues, which are all placed in the north and south walls of the several apartments. The ventiduets being at the opposite ends of these apartments, all occur in the walls that line the central hall, and are all brought together into one large tube or duct in the loft. This tube, which is about seven feet in diameter, is equal in capacity to that of all the separate ducts combined. It passes out ten feet beyond the roof, and is surmounted by one of Emerson's ventilating caps, with a dise of about ten feet diameter. Into this large tube or chamber, just below the roof, a coal stove is introduced, by which a large amount of hot air may be generated, and an impetus may be given to the ascending current to any extent that is desired.

This part of the arrangement is deemed especially important. In clear, cold weather, when the furnaces are in action, and a current of warm air is constantly setting into one extremity of an apartment, it is not difficult to establish and maintain an ascending exit current from the other end. The air is forced into the ventiduet by the constant pressure from the other end. Moreover, it enters the ventiduet already warmer than the external air. The ventiduct itself becomes warmed; and so the current, once established, perpetuates itself. But when the furnaces are not in operation, nothing of this sort takes place. And yet, this occurs precisely in those parts of the year, when ventilation in a school-room is most needed, viz.: in moderate weather, when it is not warm enough to open the doors and windows, and yet not cold enough to maintain a fire. At such times, the stove in the loft, acting directly and powerfully upon the ventiduct, will at all times create an ascending current, sucking the foul air up, as it were, from the several apartments, and thereby causing fresh air to enter from the other extremities. The position of the windows, directly opposite the ventiduets, gives a special facility for this purpose, when the furnaces are not in action. The windows, at such times, take the place of the warm air flues in supplying a stream of fresh air.

The following additional particulars may be mentioned in regard to the apparatus for heating and ventilation. The flues are all made large, both those for the admission, and those for the exit of the air. The dimensions of the several ducts are given in the engravings. In the large lecture room, the two warm air flues have together a capacity of about six square feet; and the two ventiducts for the same have, together, a capacity of twelve square feet. In the class-rooms, which are thirty-eight feet by twenty-two, the warm air flues average one and one-sixth square feet, and the ventiducts two and one-third square feet. In all the rooms, the warm air is introduced at the bottom of the apartment, as near as possible to the level of the floor; and the ordinary opening for the escape of the foul air is also on the level with the floor, at the opposite extremity, so as to sweep constantly the lower stratum of air, in which the pupil is immersed. The ventiducts are also supplied with openings at the ceiling, to be used, not in ordinary, but whenever needed, to get rid of excessive heat. In reckoning the advantages of the buiding, in respect to pure air, especial emphasis should be given to the commendible heht of the ceilings. Each apartment has a large volume of air at its disposal, in proportion to the area of its floor; and it is obvious, that the air of a room eight or ten feet high, is much more rapidly vitiated than that of one fifteen or twenty feet high.