9 6 



CARE OF THE EYES; WORK TABLE 



[Ch. Ill 



remaining nearly in a condition of rest as for distant objects. The 

 fatigue incident upon using the microscope at first is due partly at 

 least to the constant effort on the part of the observer to remedy the 

 defects of focusing the microscope by accommodation of the eyes. 

 This should be avoided and the fine adjustment of the microscope 



used instead of the muscles 

 of accommodation. With a 

 microscope of the best qual- 

 ity, and suitable light — that 

 is, light which is steady and 

 not so bright as to dazzle the 

 eyes nor so dim as to strain 

 them in determining details 

 — microscopic work should 

 improve rather than injure 

 the sight. 



If artificial light must be 

 used, give it daylight qual- 

 ities by placing a piece of 

 ground daylight glass be- 

 tween the source of light and 

 the microscope. This will 

 give one a very soft light like 

 that from a white cloud 



(§92). 



§ 162. Position and char- 

 acter of the work-table. — 

 The work-table should be very 

 firm and large (61 x 122 cm. 

 on top, and 73 cm. high; 24 X 48 X 29 in., fig. 57), so that the neces- 

 sary apparatus and material for work may not be too crowded. The 

 table should also be of the right height to make work by it comfort- 

 able. An adjustable stool, something like a piano stool, is convenient; 

 then one may vary the height corresponding to the necessities of 

 special cases. It is a great advantage to sit facing the window if day- 

 light is used; then the hands do not constantly interfere with the il- 



Microscopical Laboratory 

 Desk. 



Fig. 58. 



(Designed by Dr. V. A. Moore.) 



The size of the top and the height are the 

 same as for the laboratory table (fig. 57). 



At the right there is a cabinet with com- 

 bination lock (10, cl) for a microscope, and 

 above a drawer with combination lock (cl). 



At the right is a writing shelf (s) and four 

 drawers. 



Near the bottom is a brace (br) which also 

 serves as a foot rest. (M), (c LS), (Sh), 

 (a), a microscope, a lamp and a shield with 

 daylight glass in the aperture. 



