The above are the heights adopted in the Boston schools.

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Dimensions of Schoolrooms, Boston Schools. The sizes of the rooms in the Boston schools, as adopted by the School Board, are: for grammar schools, 28 feet × 32 feet × 13 feet 6 inches high; for primary schools, 24 feet × 32 feet × 12 feet. This accommodates 56 scholars per room, in each grade, allowing 216 cubic feet per scholar in the grammar schools, and 165 cubic feet in the primary grade.

Dimensions and Weight of Fire-Engines. — From measurements of different fire-engines belonging to the city of Boston, it was found that the greatest length, including pole, was 22 feet 6 inches. The widths varied from 5 feet to 5 feet 11 inches, the average height being 8 feet 8 inches.

The average weight of 29 engines is 8000 pounds; the greatest weight being 9420 pounds, and the least 4780 pounds.

Dimensions and Weight of Hose Carriages. Extreme length, with horse, 19 feet 6 inches; without horse, 17 feet 6 inches. Width, 5 feet 9 inches to 7 feet 0 inches; height, from 6 feet 8 inches to 7 feet 0 inches; average weight of 11 carriages, 2943 pounds; greatest weight, 3500; least weight, 2120.

Dimensions and Weight of Ladder Wagons. Length of truck, 33 feet; total length, with ladders on, 45 feet; width, 6 feet 2 inches; average weight of 12 wagons, 6660 pounds; greatest weight, 8800; least, 4350.

Dimensions of Carriages.- Covered Buggy (Goddard). ― Length over. all, 14 feet; width, 5 feet; height, 7 feet 4 inches. Will turn in space from 14 to 20 feet square, according to skill.

Coupé. Length over all, 18 feet; width, 6 feet; height, 6 feet 6 inches.

Buggy (Piano Box). - Length over all, 14 feet; width, 4 feet 10 inches.

Landau.-Length over all, 19 feet 6 inches; width, 6 feet 3 inches; height, 6 feet 3 inches; length of pole, 8 feet 0 inches.

Stanhope Gig (2 Wheels). — Length over all, 10 feet 6 inches; width, 5 feet 8 inches; height, 7 feet 6 inches.

Victoria. - Length, without pole, 9 feet 6 inches; length of pole, 8 feet; width over all, 5 feet 4 inches.

Light Brougham. — Length, without pole or shaft, 9 feet to 11 feet; width over all, 5 feet 4 inches; height, 6 feet 4 inches.

WEIGHT, PER FOOT, OF RAYMOND'S COMPRESSED LEAD SASH WEIGHTS.

WEIGHT OF LUMBER PER THOUSAND (M) FEET.

EXPLOSIVE FORCE OF VARIOUS SUBSTANCES USED FOR BLASTING, ETC.

(Builders' Guide and Price Book. - HODGSON.)

The above table is by the celebrated M. Berthelot, who further describes nitro-glycerine " as really the ideal of portable force. It burns completely without residue; in fact, gives an excess of oxygen; it develops twice as much heat as powder, three and a half times more gas, and has seven times the explosive force, weight for weight, and, taken volume for volume, it possesses twelve times more energy." From the extreme danger of the work, none but a competent chemist should attempt to manufacture it.

The Cutler Patent Mailing System, or United States Mail Chute, has now come to be very generally used in office buildings, public buildings, hotels, and apartment houses, in connection with which the United States free collection service is available. It is, there' fore, important that architects should be informed with regard to the simple but necessarily rigid conditions under which this method of handling mail can be availed of.

The chute must extend in a vertical line, must be exposed to view and accessible throughout its entire length. It is made in removable sections, to facilitate clearing it in the event of accident.

The Cutler Manufacturing Company, of Rochester, N. Y., who are the owners of the original and subsequent patents under which the device is manufactured, publish this information at length, illustrated by detail drawings, which can be obtained by any architect, on application, and without charge.

REFRIGERATORS.

The following information is given as a guide to architects in providing for refrigerators in fine residences, hotels, club buildings, etc. A consultation with some reliable refrigerator builder, however, is always wise before deciding in relation to space to be occupied by refrigerators, refrigerating rooms, freezers, etc., as a satisfactory refrigerator cannot be adapted to a badly proportioned space. Care should be taken to select a refrigerator simple in its working and easily cleansed, as modern sanitary science has traced much sickness to poor refrigeration. Thorough insulation is one of the most important features in a refrigerator, as upon this depends economy in the use of ice, the keeping of the cold air, and the consequent perfect preservation of the food.

Fig. 1.

Fig. 1 is a kitchen refrigerator for use in families of ordinary size, and has the ice located in the centre. Depth should not be over three feet nor under two feet. Height may be four to seven feet. Length of front largely determines the capacity, and should be, say, from five to seven feet.

Fig. 2 shows greater capacity, and is better adapted for use in large families, entertaining considerably, and for small clubs, boarding-houses, restaurants, private hospitals, etc. This style is known as a "combination " refrigerator, from the fact that it contains separate compartments for the various kinds of food. The large compartment at the left is specially for large meats, and packages in bulk, and is fitted with shelves and meat hooks. The

right end of the refrigerator is divided by a partition into two compartments, the drawers being for steaks, chops, jellies. etc., and the door above for vegetables and sundries. The compartment to the right of this is specially for milk and butter, and should be absolutely separate from all other com

Fig. 2.

partments. One ice tank supplies cold air to all compartments, and is filled through a door in the front.

A convenient arrangement is a window in the wall at back of refrigerator, through which ice may be passed into refrigerator. Refrigerators over two feet in depth should be built in sections