Culver & Co. also make, and put up, various sizes of Portable Furnaces, with metallic coverings, suitable for counting rooms, stores, school-rooms and small houses, warming the rooms in which they stand, as well as others in the same building, and they can be removed in summer as conveniently as stoves.

Figure 2 represents a section of large size Portable Furnace or double casings of sheet iron or zinc. The same letters for reference are used as in Fig. 1. Figure 3 represents a smaller size Portable Furnace, with two metal coverings and an evaporating dish standing upon the top of the drum.

The peculiarities and advantages of the Furnace are thus set forth: 1. Its compact, convenient and beautiful form.

2. Its great durability; being in all its parts of cast iron, set within walls of brick masonry. The pot or burner being whole, is found by experience to be more durable than those made of rings or segments, and entirely prevents the admission of gas into the hot-air chamber.

3. The great radiating surfaces of this Furnace exceed those of any other, and being nearly all perpendicular, and so arranged as to afford no chance for the soot, light coal ashes or dust to collect on the plates and prevent the transmission of heat through them, for it must be obvious to every thinking mind, that if a radiating surface is of a zig-zag, or any other form that prevents the descent of dust or soot in a perpendicular line, it will certainly collect dust upon it, and just so much surface thus covere 's destroyed for radiating purposes, and in the same proportion will a greate, consumption of fuel be required to produce a given result.

These furnaces are so constructed that heat acts actively upon those surfaces within, and produces the immediate and powerful heating of the cold air that is admitted to the outer surface from the atmosphere, through the tubes for that purpose.

4. The great economy in the use of fuel, making and controlling more heat than by any other process of using it.

5. The joints of this Furnace are so constructed that the expansion and contraction of the metal cannot open them to admit gas into the hot-air chamber, and it can be cleaned of soot and ashes easily, without the necessity of taking down or breaking a joint; its action is simple, as easily understood and managed as a cylinder stove, and as readily repaired and kept in order, and the manner of "removing the deposits" is entirely novel and most efficient.

6. The constant current of the pure atmosphere into the air chamber, with

the evaporation for tempering it to any degree of humidity, gives a fine healthful ventilation, and a soft summer temperature, suited to the most delicate constitution, and without injury to the building or furniture.

The above described Air Heaters are manufactured and sold, wholesale and retail, by Culver & Co., who, when required, set them in double walls of brick masonry, with cast iron smoke pipe to chimneys, and conductors of hot air, of double cross tin, terminating with registers in the rooms, and secured safely from fire by tin or soap-stone linings.

Figure 4 represents patterns of scroll work Registers manufactured by Culver & Co., and put in with their furnaces if desired. The registers have valves under the surface, which are easily controlled by means of the star centers. They can be used for ventilating purposes as well as for admitting warm air.

The following directions are given in Culver & Co.'s Circular for the use of their Furnace.

DIRECTIONS FOR USE.-In kindling the fire, the valve should be opened by drawing out the Damper Rod R, so as to let the smoke pass directly through smoke pipe M to chimney.

Shavings, pine wood, or charcoal, should be thrown into the pot or coal burner C, and when well ignited, put in about half a hod of coal, and as soon as it also becomes ignited, fill the pot two thirds full of coal, and push the damper R partly in, so as to regulate the draught and heat as may be necessary. The valve may be entirely closed, if need be, so as to retain the heat, making it to pass through the Flat Radiator K.

In moderate weather, when little heat is wanted, put two shovels full of ashes on the centre of the fire, and by regulating the draught, you can make one fire last 24 hours without any alteration; and when you wish to renew the fire, poke out a portion of the ashes, and put on fresh coal, without turning the grate. In cold weather, however, to secure a brisk fire, the crank should be turned so as to empty the pot entirely of ashes, and commence a new fire at least once in 24 hours.

When there is too much heat generated, the ash-pit door, B, should be closed entirely, and the damper rod partly drawn out, and if this is not sufficient, the Register in feed-door P may be opened; the heat in the different rooms may be regulated by opening or closing the Registers; all the Registers however should never be closed at the same time, unless the water door is opened to let out the hot air.

The cold-air conductor, O, should always be open when the Furnace is in operation.

PLANS AND DESCRIPTIONS OF THE PUBLIC SCHOOL-HOUSES IN PROVIDENCE, R. I.

By an ordinance of the City Council of Providence, in the spring of 1838, the public schools were reorganized, and provision was made for a liberal course of instruction, in schools of different grades, for all the children of the city. A committee was appointed to examine into the condition of the school-houses then occupied by the public schools, and report what alterations, improvements, and additional accommodations were required. This committee, after a full investigation, reported in favor of building new school-houses, on large and eligible sites, in different parts of the city. After a further report from a sub-committee, who had visited Boston, Salem, Lowell, and New Bedford, for the purpose of examining the latest improvements in the construction of school-houses, and the style and arrangements of seats and desks, plans for the different grades of schools were determined on, and the committee were authorized to purchase such new sites as should be required, and "to erect such new school-houses as may be necessary to carry into full operation" the new ordinance. This committee acted with great discretion, and, at the same time, with wise regard to the accommodations of the public schools; and the result was, that, at the close of their work in 1842, no city in the United States could show so many public school-houses, uniformly well built, with most of the latest improvements, as Providence.

Since 1842, great improvements have been introduced into this class of buildings, in many of the large cities and villages of Massachusetts, as well as in the large districts of Rhode Island; and it is feared, that, in respect to ventilation, size of recitation rooms, and suitable accommodation for hats and outer garments, the public school-houses of Providence can no longer claim that superiority in school architecture which has been heretofore very generally, and most justly, accorded to them.

From the Report of the Building Committee to the City Council, giving the details of their proceedings and expenditures, it appears that they expended in the purchase of lots and the erection of buildings, $100,060.92. Since this committee completed their duties, ten new houses have been erected, making the aggregate amount invested by the city in school-houses, lots, and furniture about $150,000. The following plans and descriptions of these houses are taken, with permission, from the Report of Nathan Bishop, Esq., Superintendent of Public Schools in Providence dated August, 1846.

PRIMARY SCHOOL-HOUSES.

THESE buildings are located in different parts of the city, and are designed for the accommodation of children from four to six or seven years of age, or until they are prepared to enter the intermediate schools.

These school-houses stand back from thirty to sixty feet from the line of the street, and near the center of lots varying from eight to one hundred feet in breadth, and from one hundred to one hundred and twenty feet in length. Each lot is inclosed by a neat and substantial fence, six feet high, and is divided into two yards-one for boys and the other for girls-with suitable out-buildings, shade trees, and shrubbery.

These houses are each forty feet long by thirty-three feet wide, with twelvefeet posts, built of wood, in a plain, substantial manner, and, with the fences, are painted white, presenting a neat and attractive exterior.

The entrance is into a lobby [A] and thence into an open area, where stands the stove [a]. A portion of the lobby is appropriated to bins for charcoal [c] and anthracite [d], which is the fuel used in all the schools; the remainder [B] is occupied by a sink, and as depositories for brooms, brushes, &c. Each room is arched, thereby securing an average height of thirteen feet, with an opening in the center of the arch, two feet in diameter, for ventilation. The ventilator is controlled by a cord passing over a pulley, and descending into the room near the teacher's desk [b]. In each end of the attic is a circular window, which, turning on an axis, can be opened and closed by cords, in the same manner as the ventilator.

The teacher's platform [C] is five feet wide, twenty feet long, and seven inches high, with a black-board ten feet long and three feet wide on the wall in the rear.

The floor is of inch and a half plank, tongued and grooved; and, for the purpose of securing warmth and firmness, and avoiding noise, is laid on

cement.

The windows, eleven in number, of twenty-four lights, of seven by nine glass, are hung with weights, and furnished with inside blinds. The sides of the room and entries are ceiled all round with wood as high as the windowsills, which are four feet from the floor. The rest of the walls are plastered, and covered with white hard finish. Each room is provided with sixty seats [s] and desks [], placed in six ranges; each range containing ten seats and desks, of three different sizes, and each seat and desk accommodating two scholars, or one hundred and twenty in all.

The center aisle is three feet and a half wide, and each of the others about two feet.

The desks are over three feet long, by sixteen inches wide, with a shelf beneath for books. The upper surface of the desk [a], except about two inches at the top [b], slopes one inch and a half in a foot.