PARIS GREEN. Ill 



ADULTERATIONS OE PARIS GREEN. 



Paris Greens have been frequently examined in different parts 

 of the country and while there have been occasional samples that 

 have been found to be adulterated with materials which do not 

 normally enter into the composition of the goods, for the most 

 part, they are free from foreign admixtures. The most danger- 

 our adulteration, if it may be so called, is the presence of an 

 excess of arsenious oxide. This is the cheapest ingredient of 

 Paris green and there is a constant temptation to add as great 

 an excess of arsenious oxide as is possible and obtain a good 

 color. From the standpoint of an insecticide, the presence of 

 an excess of arsenious oxide is serious because it endangers 

 foliage to which the green is applied. 



From investigations made at the New Jersey Agricultural 

 Experiment Station,* it is found that there is generally a short- 

 age of weight and that while as a rule the gross weight of the 

 packages is equal to or slightly in excess of what is claimed, 

 they fall short in net weight from 4 to 10 per cent, — that is the 

 purchaser usually pays for the container at the rate of 30 to 35 

 cents per pound. 



ORDINARY IMPURITIES OE PARIS GREEN. 



Six samples of Paris green were analyzed at this Station to 

 determine the water, sand and sodium sulphate which they car- 

 ried. The water ran from 1.14 to 1.50 per cent. A few years 

 ago the Bureau of Chemistry of the U. S. Department of Agri- 

 culture analyzed 45 samples of Paris green, and the water run 

 from .33 to 1.24 per cent. It will be noted in these samples, the 

 water has been increased nearly a per cent and while the water 

 in the Paris green does no harm, it is a shortage in weight. 



The sand is incidental to the manufacturer but is practically 

 the same as existed in the greens of a few years ago. Sodium 

 sulphate is an impurity incident to the manufacture of Paris 

 green but if the greens are at all carefully washed, there should 

 be considerably less than one per cent. It will be noted in one 

 instance that the sodium sulphate run up to 2.4 per cent. These 

 ordinary impurities average in the 6 samples in the aggregate 

 2.75 per cent which is double what there should be in well made 



* Bui. 205 New Jersey Station. 



