170 



ELEMENTARY CHEMICAL MICROSCOPY 



hard, the blades are moderately flexible and the teeth sharp 

 The wide blades have usually about 20 teeth to the inch and the 

 narrow blades about 28 teeth to the inch. A tool of this sort 

 is of constant use in industrial microscopy. 



A tiny tool-makers' vise and tiny steel clamps are necessary 

 adjuncts to the Greenough type binocular microscope. They 

 #re employed to hold a specimen firmly, from which particles 

 are pricked out with needles or chiseled out with tiny cold chisels 

 ahd a tiny hammer. The " set up " for work of this nature is 

 shown in Fig. 30. The removal of particles for subsequent 

 analysis is more conveniently done under the binocular micro- 

 scope than under a simple magnifier. 



The loosening of particles from other material in which these 

 particles are imbedded may often be accomplished by dissect- 

 ing instruments; the most useful of those of small size are illus- 

 trated in Figs. 108, 109 and no. The chemist will find instru- 



FIG. 108. Spear Point Dissecting Needle of " Stellite." Xf . 



ments made of " stellite " 1 superior to those of steel. This alloy 

 is harder than steel, stainless, rustless and resists the attack 



FIG. 109. Knife Needle of " Stellite." Xf. 



of most chemicals with which the instruments come in contact. 

 The author has found them to hold an edge well and to be easily 



FIG. no. " Eye Spud " of " Stellite " converted into a narrow chisel. X| 



sharpened and kept in good condition; their superiority over 

 steel in the chemical laboratory is very great indeed. 



1 " Stellite " is an alloy of cobalt, chromium and tungsten with a little iron, 

 nickel, manganese, carbon and silicon. Dissecting 'instruments made from this 

 alloy may be obtained from the Haynes Stellite Co., Kokomo, Ind. 



