PYRETHRUMS. 



39 



presence of barium or lead chromate), ether extract, and qualitative 

 tests for lead, barium, chromium, and tumeric. 



Moisture. This is determined by dr} r ing a weighed quantity of the 

 powder for from 12 to 1-i hours in hydrogen at the temperature of 

 boiling 1 water, and reporting the loss as moisture. 



Ajsh. Burn the dried, weighed portion from the moisture deter- 

 mination at a low red heat until a white ash is obtained. The residue 

 is reported as ash. 



Ether extract. Extract a weighed portion of about 2 grams of the 

 powder for 16 hours with ether in any of the ordinary extraction 

 apparatus. Drive off the ether on the steam bath and dry at a tem- 

 perature of about 70 C., not leaving the extraction flask in the oven 

 longer than necessary. The residue is reported as ether extract. 



Lead, barium, and chromium are tested for in a nitric acid solution 

 of the ash by the ordinary methods employed, and chromium by the 

 1)0 rax bead test, using a small quantity of the ash. 



Tumi < I'!'-. Treat a portion of the powder with alcohol and filter off 

 the extract. Saturate a piece of filter paper with the extract and dry 

 on a watch glass over the steam bath. Repeat three or four times. 

 Now dip the paper in a solution of borax slightly acidified with hydro- 

 chloric acid. I )ry on a watch glass over the steam bath, and if tumeric 

 is present a cherry-red color appears. 



ANALYSES AND DISCUSSION. 



In Table VI, following, are the analyses of 10 samples ot pyretnrums 

 or imitations thereof. 



TABLE VI. Composition of pyrethrum. 



"CHARACTER OF ETHER EXTRACT. 



19528. Black, tarry oil; strong smell of pyrethrum. 



19529. Brown oil; strong smell of pyrethrum. 



19530. Greenish-brown oil; not very strong smell of pyrethrum. 

 19559. Greenish-brown oil: not very strong smell of pyrethrum. 

 1%77. Black, tarry oil; strong smell of pyrethrum. 



20371. Green oil: some smell of pvrethnnii. 



20483. Dark green, tarry oil; strong smell of pyrethrum. 



20485. Light green oil: strong smell of pyrethrum. 



20486. Dark green, tarry oil; strong smell of pyrethrum. 

 204*7. Dark green, tarry oil; some smell of pyivthrnm. 

 bSee correspondence with manufacturers, page 60. 



