FIG. 1 86. The platinum loop used in making the borax bead test. 



When you tested a number of substances with litmus 

 paper to find out which of them were acids, you were 

 really doing some work in chemical analysis. Chemists 

 actually use litmus paper in this way to find out whether 

 a substance is an acid or a base. 



The borax bead test. This is another chemical test, 

 by which certain substances can be recognized : 



Experiment 113. Make a loop of wire about a quarter of 

 an inch across, using light-weight platinum wire (about 

 No. 30). Seal the straight end of the wire into the end of 

 a piece of glass tubing by melting the end of the tube around 

 the wire. 



Hold the loop of wire in the flame of a Bunsen burner for 

 a few seconds, then dip the looped end in borax powder. 

 Be careful not to get borax on the upper part of the wire or 

 on the handle. Some of the borax will stick to the hot loop. 

 Hold this in the flame until it melts into a glassy bead in the 

 loop. You may have to dip it into the borax once or twice 

 more to get a good-sized bead. 



When the bead is all glassy, and while it is melted, touch 

 it lightly to one small grain of one of the chemicals on the 

 " jewel-making plate." This jewel-making plate is a plate 

 with six small heaps of chemicals on it. They are: man- 

 ganese dioxid, copper sulfate, cobalt chlorid, nickel salts, 

 chrome alum, and silver nitrate. Put the bead back into 

 the flame and let it melt until the color of the chemical has 



