86 CALIFORNIA ACADEMY OF SCIENCES. 



of funnel called thistle-shape, or, better, poppy-head shape. 

 It must hold 30 to 40 c.c. A mark bj file or paper glued 

 on shows when the funnel is filled with 20 c.c. I measure 

 the solution of caustic soda to be tested and dilute to a 

 round figure, say 100 c.c, add litmus and fill into the flask, 

 opening the clamp. By blowing through the tube I raise 

 20 c.c. into the funnel and close the clamp. I note the 

 stand of the burette, say = 0.00 c.c, add one drop of stand- 

 ard acid; the solution remaining blue, I may add four more 

 drops for the 80 c.c. in the flask, because f = 20 c.c were 

 not changed. I do so; find that I have been using .25 c.c 

 in five drops, that the liquid remained blue, and that I may 

 add safely 4 X .25 or 1.25 c.c, including the five drops al- 

 ready given. I bring the burette to 1 c.c. to get at round 

 numbers; still blue color. I may add four more c.c, and 

 do so, ^ c.c at a time, stirring with a little glass rod which 

 I leave always in the funnel, and observe that with 3 c.c 

 the contents remained blue, but become red with 3|cc Now 

 I know that the final reaction w^'ll occur between 3X5= 15, 

 and 3| X 5= 17f c.c I open the clamp and run standard 

 acid to the 15 c.c mark of the burette, shake and wash the 

 funnel by raising and lowering repeatedly the mixed liquid. 

 I raise again to 20 c.c in the funnel, close the clamp and 

 begin my second test, adding, as before, 1 drop; the liquid 

 remaining blue, I add 4 more. Still blue. I may, conse- 

 quently, give 5 X -26 c.c = 1.25 c.c I do so, but only .10 

 c.c or 2 drops at a time, because I know that I am ap- 

 proaching the final reaction below 17.5 c.c Having added 

 .30 c.c, the liquid remains blue, but turns red at .40 c.c I 

 may add 5 X .30 but not 5 X .40 c.c. I open the clamp 

 and proceed as before, bringing the burette to 16.50 cc I 

 raise again 20 cc, which I still, to be on the safe side, 

 count as ^, although it has become now nearly ^th of the 

 whole. I add one drop of acid: blue, another: red. I go no 

 further, because I know I am within 3 drops of the final reac- 

 tion. I remove cork and funnel and add the next drop 



