CONDITIONS OF HEALTH ESSENTIAL FOR CARRYING ON INSTRUCTION. 461 



1 A. A classroom is considered to be sufficiently lighted by daylight ' 

 in all parts in which a portion of the sky is visible by the scholar ; by 

 artificial light when small type known as brilliant can be read in any 

 part of the room at the distance of 18 inclies from the normal eyes. 

 In place of blinds a sliding screen covering only part of the window 

 should be arranged so that sunlight may be pi-evented falling directly 

 on the scholars, and that with a minimum loss of daylight. Windows 

 should always be carried as near to the ceiling as possible so as to secure 

 the largest amount of sky. The height of the window-sill from the floor 

 also requires careful consideration. It should never be so low as to cause 

 dazzling of the scholars' eyes. 



The window-glass should be perfectly clear without any muffling or 

 clouding, not only on account of securing the largest amount of light, 

 but to save the check to the eye-nerve of thwarted vision. Windows 

 ought not to be broken up by bars where these can be avoided ; and plate- 

 glass is preferable, where possible, as being a good non-conductor. It 

 retains the heat of the fire in the room, and also takes the heat out of 

 the sunlight entering the room. Careful attention .should be paid to the 

 ratio between window area and floor space. 



Reflected light from the ceiling becomes well dispersed and is steady. 



2 A. The correct position for a child, when sitting at a desk to write, 

 is such that his feet may be firmly planted on the floor or foot-rest, the 

 seat of his chair reaching forward to his knee, the back of the seat 

 supporting both middle spine and shoulders. The front of the desk 

 should come well over the knees and be at such a height that both arms 

 can be laid on it easily without raising the shoulders. The slope of the 

 desk should be about 30°, and this position will be found to bring the 

 paper at about the distance of from 18 to 20 inches from the eyes of the 

 normally proportioned child. 



In reading the slope of the book should be 45° ; and tliis exercise 

 should for the most part be taken sitting rather than standing in order 

 not to dissipate nervous energy from intelligence and eyesight ; and 

 great liberty of movement must be allowed within these requirements, 

 either when standing or sitting, to avoid strain upon the delicate nervous 

 organism. 



Desks and seats must be so placed that light falls from above (dis- 

 persed light causing no shadows) or from the left. Light must be steady 

 and not flickering, and must fall upon the work and not upon the eyes of 

 the worker. 



3 A. School books are considered to be appropriate and well printed 

 when the paper is thick enough to prevent the ink showing through ; the 

 colour of the paper slightly toned white, not glazed ; the ink a good 

 black ; the size of type pica leaded ; and the length of line about 

 four inches. 



A feeling is expressed by many that school books should be ' passed ' 

 by some hygienic authority as appropriate to eyesight before being 

 received in schools from the publishers. 



Blackboards should be slated black to receive the white chalk. They 

 should be at a maximum distance of 30 feet from the observer, should be 

 well illuminated, and the writing upon them should be well spaced and 

 not less than an inch depth. 



' Special instruments have been devised to measure esactlj' the amount of A&j- 

 Hght in any part of the room. 



