74 The Spraying of Plants. 



orchards where all the trees are sprayed. In practice we use 

 Paris green with Bordeaux mixture to prevent injury to the 

 foliage. We must use the latter to keep the leaves from drop- 

 ping prematurely. Some jar the trees occasionally in addition to 

 spraying, in order to gather and burn all of the plums which 

 are stung. If it were not for the Bordeaux mixture I think 

 that only few would spray for the curculio, but as it is I think 

 that the majority of orchardists prefer spraying to jarring ! " 



The question is evidently not yet fully settled, but apparently 

 much seems to depend upon the locality, and the time and 

 thoroughness with which the applications are made. 1 



Other Arsenites than Paris Green and London Purple. 



Paris purple, another arsenical poison, has been on the 

 market to a limited extent since 1882 or 1883. Mr. A. Poirrier, 

 president of the St. Denis Dyestuff and Chemical Co. of Paris, 

 France, was the introducer of this material. The New York 

 agents of the firm, Sykes & Street, 85 Water Street, write me that 

 it is the refuse obtained from the manufacture of magenta, or 

 violet, or both. The Paris firm has apparently given up the 

 manufacture of the product, and the stock in this country is now 

 very limited. It is used in the same way as London purple, 

 lime being added to prevent injury to foliage, but larger 

 amounts of it appear to be required to give satisfactory results. 



English purple poison, as I am informed by the introducer, 

 Henry S. Ziegler, 400 N. 3d Street, Philadelphia, Pa., has 

 been upon the market only a few years. He states that " the 

 name is original with me, and the composition consists of arse- 

 nious acid with an aniline base." It seems, therefore, that the 

 last three poisons mentioned, London purple, Paris purple, and 

 English purple poison, are derived from the same source, 

 although there are undoubtedly certain variations in their 

 texture and composition. (For analyses see page 123.) Con- 

 siderable quantities of soluble arsenic are present in English 

 purple poison, so it should be used with lime to prevent injury 



1 Much information on this subject may be found in the following places : 

 Ohio Agric. Exp. Sta. Vol. iii. second series, 1890, Bull. 8 ; Ibid. Vol. iv. second 

 series, Bull. 2 ; Minn. Agric. Ewp. Sta. 1890, Bull. 10, 71 ; Texas Agric. 

 Exp. Sta. 1894, Bull. 32, 494 ; Bailey, Annals Hort. 1889, 63. 



