42 INSECTICIDES AND FUNGICIDES. 



Saturate a weighed quantity of the sample with a weak solution of 

 sodium hydroxid dry, and burn at a low temperature. Transfer the 

 ash by means of hydrochloric acid and water to a flask, add some 

 methyl alcohol (previously boiled with strong potassium hydroxid and 

 distilled to break up organic acids), and distill with an apparatus such 

 as is shown in fig. 1. 



The flask is heated by means of a paraffin bath to about 140 C. 

 After the flask becomes dry remove the paraffin bath, let the flask 

 cool, add 10 cc of methyl alcohol, restore the paraffin bath to its place, 

 and distill again. Repeat this treatment until all of the boric acid 

 has distilled over, as is shown by testing a drop or two of the distillate 

 and afterwards the residue in the flask with tumeric paper. Now 

 make the distillate slightly alkaline with sodium hydroxid and evapo- 

 rate on the steam bath to dryness. Add some water, and from this 

 point on proceed just as described above where a water solution of 

 the substance is made at once; that is, first make acid with dilute sul- 

 phuric acid, boil, cool, titrate to a pure yellow color with standard 

 sodium hydroxid, add glycerin and phenol phthalein, and titrate to a 

 pink color with the standard sodium hydroxid. 



ANALYSES AND DISCUSSION. 



In the table on the next page are given the results obtained upon 

 fourteen samples. 



