38 INJURIOUS INSECTS OF 1903. 



It is to be noted that both wholesalers and retailers probably 

 act in all good faith in handling Paris Green. They have no 

 means of testing it, and there is as a rule nothing in its appear- 

 ance to cause suspicion. 



It will be seen from the above table that the ammonia test, 

 the microscope test and the chemical analysis do not always 

 tally, as might have been expected, from the fact that soluble 

 arsenic, which would show under the microscope as small 

 granules, and would be detected in chemical anaylsis, may be 

 entirely dissolved in ammonia. The microscope test and the 

 chemical analysis, however, bear each other out, as will be 

 noted in Nos. 6 and 7. 



A large amount of soluble arsenic is undesirable, since this 

 is what burns the foliage. A high grade Paris Green should 

 contain from 56 to 59 per cent total arsenic and a minimum 

 amount of soluble arsenic. With these data in mind the reader 

 can readily tell from the above table which are the good and 

 which the poor samples. In purchasing Paris Green it is wise, 

 in our estimation, to reject pale samples. 



Note that No. 6, manufactured in New York, would be 

 classed as "pure" under original New York law, because the 

 total arsenic is above 50 per cent, and the excess arsenious ox- 

 ide which may have been added to bring it up to the required 

 per cent does not have to be accounted for. As stated before, 

 the law is now so amended that any such practice in New York 

 is impossible. 



Over 3V2 per cent of soluble arsenic in any sample indicates 

 an excess which renders it undesirable for use on foliage. This 

 ruling brands samples Nos. 7, 12, 15, 16 and 18 as bad; No. 7, 

 showing 18 per cent of soluble arsenic, strikingly so. No. 5, 

 made by the same party, is in marked contrast to this, showing 

 only 1.8 per cent soluble arsenic. Nos. 12, 15, 16 and 18 are 

 all made by Ansbacher & Co. Here again we must also note 

 samples Nos. i, 2, 8, made by the same firm, and making a very 

 good showing as regards soluble arsenic. In No. 6 the micro- 

 scope showed the presence of a material soluble in ammonia, 

 since the ammonia test gave no sediment. Arsenic is soluble 

 in this liquid, and that this was the material seen under the 



