surface should not be glossy and should either be coated with an oil paint, so that the walls may be washed, or, better, calcimined with a water paint that may be readily renewed. The ceiling should be white, so as to reflect the light.

The School Furniture.-The most important articles of school furniture, considered from the view of hygiene, are desks and desk chairs, for the reason that the pupil spends during school hours so much time at work at his desk. Unless, therefore, desks and chairs are constructed. with full regard for certain well-known laws of hygiene they produce defects of eyesight, injurious effects as to posture, and wrong habits. of carriage which are borne through life and, sadly enough, become more pronounced as the years increase.1

Professor Bowditch of Harvard University carefully measured and weighed 25,000 school boys and girls of Boston and found surprising variations. Taking ages on their last birthdays Professor Bowditch found the following variations in height:

Besides the variations in height there is also variation in growth, and provision for this difference must therefore be made in the construction and adjustment of the desk and seat. The growth of girls is more rapid from 12 to 14 years of age, while boys grow most rapidly from 14 to 16 years of age. The annual growth during the maximum period is often an inch more than the annual growth at other periods. Further, there exist certain anatomical differences of proportion between boys and girls. The sitting height of girls is greater proportionately than their standing height in comparison with boys.

THE DESK AND SEAT.-The desk and seat must therefore be adjusted so as to provide for differences of height and differences of growth. The desk must not be a prison stall, but should be comfortable and 'Shaw, Edward R.: "School Hygiene." The Macmillan Co., N. Y., 1902.

roomy. It must not favor the development of myopia and must not force a pupil into wrong postures. The matter is of greater importance than school men generally recognize.

The chair and seat should be of such a height that the thigh of the pupil when seated will be perfectly level, the lower leg being in an exactly vertical position, with the foot resting wholly upon the floor; that is, the thigh and the lower leg will, when the chair is of a proper height, form a right angle with each other. The seat must therefore be adjusted accordingly. The seat itself should not be flat, but somewhat

FIG. 139.-FAULTY POSTURE. (Shaw's "School Hygiene," Macmillan Co.)

concave, the lowest part of the concavity being where the tuberosities of the ischium rest. The concavity has the additional advantage of counteracting the tendency to slide forward on the seat when the pupil leans back. The seat should have a back rest that will support the small of the back properly without leaning back excessively. Whether or not it supports the rest of the back is of small consequence. Support of the back carried to the level of the shoulder blades is likely to do more harm than good.

The distance between the seat and the desk should be such that the scholar may read at the desk and write on it without leaning forward more than a little and without entirely losing the support of the back

rest. The desk should not be so close as to press against the abdomen, nor near enough to interfere with easy rising from the seat. This means a distance of 102 to 142 inches from the edge of the desk to the seat back. It also means that the seat must not project under the desk more than an inch at most. The desk should be high enough for the arm to rest comfortably without much resting of the elbow; not, however, so low that the scholar must bend down to write on it.

FIG. 140.-THE HEUSINGER DESK. (Shaw's "School Hygiene," Macmillan Co.)

If the desk top is made to slide backward and forward it will give the pupil more freedom of movement while at the desk and will also permit him to sit down at the desk and rise from it with greater ease. One of the important considerations of a school desk is the proper slope of the top. It is well known that the line of sight which least taxes the eyes should fall upon the printed page perpendicularly to its

plane. To accomplish this some writers recommend a slope of 45° for the desk top; others 30°. These angles, however, are not practicable. The Vienna Expert School Expert School Desk Commission recommends an angle of 15° for the desk top, which is also approved by the experiments of Shaw.

ture in vertical writing.

Such a slope permits a perfect pos

A foot rest is sometimes attached to desks. The weight of opinion. is now against foot rests, as they restrict the free movement of the pupil's feet while at the desk and interfere with opportunity to shift his feet and legs for relief from inactivity, and further interfere with the thorough cleansing of the floor under the desk. Shaw recommends the Heusinger desk, Fig. 140, and also the Ideal desk. The desk and

seat shown in the accompanying photograph, Fig. 141, are known as the Boston school desk and chair. There are now many thousands in use in the Boston schools, and they are being adopted elsewhere.

The seat and chair should be adjusted for each pupil when he enters school or is transferred to another room. Desks and seats should be adjusted at least twice a year: at the opening of school in September and again in February or March.

THE BLACKBOARD.-The blackboard should be placed upon the wall opposite the principal light. The board should not have a shiny, reflecting surface, and should never be

FIG. 141.-BOSTON SCHOOL DESK AND placed between windows or near

CHAIR.

them.

The best blackboards are made of slate, as they can be washed, which lessens the dust nuisance. The best slate for this purpose is a greenish or strong black color, which is to be preferred to the grays and brownishblacks. Colored crayons made with arsenic or sulphid of mercury carry danger and should be prohibited.

Posture. Every condition must be eliminated and every care exercised to prevent the acquiring of physical defects in school, as well as to prevent the accentuation of those physical defects which the child may have possessed before entering school. Posture during sitting is of greater consequence than posture during standing, on account of the longer time the child sits and the muscular fatigué caused by the inactivity of a great number of muscles of the body for a long period.

Stooping over the desk leads to myopia; it also contracts the chest and interferes with free respiration, and puts additional labor on the heart; it results in round shoulders and curving of the spine backward and a carriage in which the head is pitched forward; it also tends to displacement of the internal organs, both of the abdomen and pelvis.

In order that the pupil may be in a proper physical condition to maintain an erect posture while in his seat, and thus form correct habits which he will carry through life, he must be given periods of relief from sitting at the desk and corrective exercises at different times during the day. In the first year the child should not be confined at his desk more than one-third of the time. In the succeeding years the total amount of time occupied at the desk may be gradually lengthened. In addition to the regular recesses there should be frequent short intervals of respite from sitting at the desk devoted mostly to some form of physical exercise.

A recess of not less than 20 minutes during the morning session and again during the afternoon session, when all pupils, if the weather and climate permit, go out of doors and engage in some form of active play, is of incalculable value in its results upon physical health and mental development. In addition there should be given to each grade every school day at least two short periods of systematic physical drills with the windows open.

Lighting. The light must be of proper intensity, equally diffused, and come from the proper direction. So far as intensity is concerned the light must be neither too dim nor too strong, both extremes being harmful. The general rule is that the amount of transparent glass surface admitting light should be from one-sixth to one-fourth of the floor space. The correct amount of window space will depend on the location of the building, direction from which the light is admitted, size and shape of the room, and the proximity of other buildings or objects which might obstruct the light.

The amount of transparent glass surface required for proper illumination must be great enough to afford sufficient light on rainy, overcast, and cloudy days. Excessive window space is scarcely possible, for the excess illumination on bright days may be regulated and softened with shades and awnings.

The amount of illumination is measured by candle meters or candle feet; that is, the illumination afforded by a standard candle at a distance of one meter or one foot. Shaw1 believes that the illumination should provide at least 50 candle meters in the most unfavorable part of the room.

Factory-ribbed glass or Luxfer prisms, which refract the light into the parts of the room where the light is needed, are a very decided ad'Shaw, Edward R.: "School Hygiene." The Macmillan Co., N. Y., 1902.