130 ELEMENTARY CHEMICAL MICROSCOPY 



as far away from the microscope as possible and yet the "instru- 

 ment must be readily and immediately accessible without ma- 

 terial change of position. The indented table offers a ready 

 solution of this problem for if the microscope be placed to one 

 side of the indentation and the micro-burner and reagents on the 

 opposite side the worker has only to swing to the left or right as 

 the case may be to change his position from the most convenient 

 one for manipulations to that for microscopic observation. Fig. 

 76 shows the construction and arrangement of a convenient work 

 table for microchemical investigations. 



When an indented table is provided with drawers as shown in 

 the illustration, care must be taken in the construction to see 

 that the depth of those nearest the cut-out section is not so great 

 as to hit the knees of the worker as he swings from one side to 

 the other. 



The table top should be of close texture and finished in a dull 

 lusterless black. A polished or shining top should be avoided, 

 since reflections therefrom are always annoying and very tire- 

 some to the eyes. Glass, porcelain or stone tops should there- 

 fore be finished with dull or "ground" surfaces, never polished. 

 Coarse-grained woods should be avoided because of the difficulty 

 of keeping them clean; for this reason the author prefers table 

 tops of white wood or poplar, stained with aniline black, un- 

 polished and unvarnished, and merely rubbed down smooth. 



To guard against disfigurement and corrosion of the table top, 

 manipulations are performed upon a square piece of plate glass. 

 A convenient size will be found to be from twelve to eighteen 

 inches square. 



When possible the work table should be piped for gas and com- 

 pressed air and be furnished with binding posts or switch for 

 electric current (direct, when available). Running water is 

 unnecessary. 



The arrangement of instruments, apparatus and reagents 

 upon the work table is shown in the cut and needs no further 

 comment. 



A stool adjustable in height and provided with a swivel seat 

 may be said to be practically indispensable. If the stool has in 



