rentrapp. The table is especially valuable as giving the correct heights for the chair and the desk-lid, which are the chief factors (see columns 3, 4, 5). The edge of the lid overhangs the seat by about two inches. If the height of the chair is reckoned from the foot-rest, the latter is supposed to be directly under the knees. The chair-seat is, in fact, much higher than is common in our schools, which encourages the habit of keeping the knees at right angles.

A rest may properly be placed under the desk. The figure represents a desk which raises the scholar a good deal (without interfering with comfort), the object of which seems to be to facilitate the master's inspection of the writing.

To complete this account, it is necessary to describe the mode recommended by Liebreich.*

1. One and the same size and model of desk should be used for children and grown-up persons of both sexes.

2. The adaptation to the height of each child should be effected by varying the height of the seat and the foot-board.

3. The edge of the table is always to be perpendicular to that of the seat.

*"School Life in its Influence on Sight; "a lecture delivered before the college of preceptors at the House of the Society of Arts, July 13, 1872. London, 1872.

4. No seat is to be without a back, and the top of this is always to be one inch lower than the edge of the table for boys, and one inch higher than the edge of the table for girls.

5. In all classes where the boys change places, the height of the seat is to be regulated in proportion to the average height of the pupils.

6. In all girls' schools, in all those boys' schools where the children do not change places, in boardingschools, and in private school-rooms, the seat of each child should be accurately regulated in proportion to its height. This is effected by a chair, the seat of which can be raised and lowered by means of a screw, while at the same time the back is brought forward in proportion.

The present writer would say that it seems to him very desirable to select seats that suit individuals, and allow them to retain such seats, instead of shifting at intervals. There is also, in some cases, much advantage in placing the near-sighted, the partially deaf, or the unruly near the front.

UNDE

CHAPTER IX.

A MODEL SCHOOL-ROOM.

NDER this heading, I wish to state a number of points which have various bearings on the health of scholars and teachers in an ordinary class-room. Shape. For reasons which will appear, a parallelogram is desirable, with the teacher's platform and desk at one end. This form is better for acoustic reasons than a square; and it gives the teacher better command over the pupils than if the desk is in the middle of one long side.

Length. The limit of distance at which large, clear writing on the blackboard is easily seen (with letters 22 inches in height) is about thirty feet. There should be a space between the rear row of desks and the wall, which may add two or three feet. The length of the room should, however, in no case exceed forty feet (Erismann), and is limited by Varrentrapp, Zwez, and others, to nine or ten meters (30 to 33 feet).

Width. This is restricted by the fact that all the windows are supposed to be placed on one of the

long sides of the room; and that these windows will not light up a room effectively if its depth exceeds a certain ratio to the height of the window. This ratio is commonly set as 3 to 2; so that if a window-head is fourteen feet above the floor (which is rarely the case), the light will penetrate effectively to a distance of twenty-one feet. Again, allow three feet for the width of the passage beyond the farthest desk, and twenty-four feet is seen to be the extreme allowable width; or, if the window is 13 feet high, about twenty-three feet.

Height. This is limited to thirteen or fourteen feet, by practical considerations, such as the expense of building and heating.

Windows.-The direction from which light comes to the desk of a scholar is of great importance. It is universally agreed that for general purposes that which comes from the left is best. Almost all authorities of scientific weight order that this be made the rule, and, in fact, the Germans generally forbid the use of windows upon any other side of the room. It may be said that light from the right hand is as useful to read by as that from the left. This is true; but in writing, such a light is very annoying. And a combination of lights from the right and left throws a double set of shadows, which is also trying to the eyes. The same may be said of a combination of light from the left and rear.

The worst light, in general, is that from directly

in front of the scholar. It pains the eye, if intense. If moderate in amount, it still inflicts an unconscious strain on the retina, by throwing on it an illumination which would be healthful if the eye were not at work on small objects, but which is a needless tax on the endurance of the laboring organ. Practically, any one may prove that it is much harder to read with the book held towards a window than with the book held away. This difficulty is felt by the scholar, who tries to remedy it in his own way.

Sometimes he holds the book closer to his eyes, which aids in developing near-sightedness. Sometimes he twists his body around so as to receive the light on his book in the natural way, and this, if allowed, may contribute to "one-sidedness" or crookedness of figure.

Windows in the rear, fronting the teacher, are very annoying to the teacher, and considerably lessen the power of watching the scholars; while for the scholars they are exceedingly bad, as they throw the shadow of the person on the desk or book.

The most agreeable light to write by is one which comes from a pretty high point, and strikes the page at a wide angle. An ordinary window will not give such a light, but may still be found very suitable if placed on the left of the scholars.

Light entering horizontally has hardly any value for a student who has to use a flat desk. The ex

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