800 
Proceedings of the Royal Society 
peroxide. To insure success, close attention should be given to 
various little details mentioned. 
The sketch shows the apparatus used, and consists of a glass tube 
A, about 4 inches long and f inch diameter, with a small bulb blown 
on the bottom capable of holding 10 c.c. It is fitted with a tight 
cork I, through the centre of which passes a small funnel tube B. 
This must reach to within \ inch of the bottom of the bulb, and 
should be fitted with a stopcock S, just below the funnel. On one 
side of the tube A, just underneath the stopper I, is the arm r , about 
1 inch long and \ inch diameter, on the end of which is joined, by a 
piece of rubber tubing, a glass tube t, bent at right angles, the long 
arm being about 5 inches ; this conveys the vapours which distil over 
into the receiving tube C an ordinary test-tube), which contains 
the solution of starch, ether, &c. 
In making an experiment, place the substance under examination 
(it is best not to use more than 0*25 grm. at once) in the tube A, 
nearly fill the bulb with water, then run down B, after warming 
slightly, two drops of dilute sulphuric acid (1 in 5). If nitrates or 
chlorates are present, the fluid will change colour, yellow or red, due 
