66 The Spraying of Plants. 



" The bill of lading shows that the kegs left New York City 

 on Feb. 2, 1878, but it was near the end of the month when 

 they reached me at Ames, Iowa. 



" My next letter from Hemingway & Co. bears date of March 

 19, 1878, asking as to the arrival of the kegs. The next 

 letter from the firm I have temporarily mislaid, but on July 

 26, 1878, it wrote as follows : ' We have to thank you for 

 your favor of the 4th inst. and are of course pleased to find that 

 our expectations are correct as to the poisonous nature of the 

 " London purple " to the potato beetle. We anxiously await 

 the result of the further experiments promised in yours, and 

 shall in the meantime have prepared some few tons of the 

 material ready to be sent over.' 



" On Nov. 28, 1878, it wrote as follows : * We are exceedingly 

 obliged for your favor of the 9th inst. and the Nos. 3 and 4 

 of your college gazette 1 (which came by same mail) containing 

 yours and Professor Budd's kind notice of our new poison 

 (London purple). Since last we had this pleasure, we have 

 been in correspondence with Messrs. Ward & Co., to whom we 

 intend sending our first consignment, and which we intend 

 shall leave hero immediately.' 



" My letter, in which I suggested the name ' London purple,' 



1 "A CHEAP AND VALUABLE POISON FOB THE POTATO BEETLE. Last winter 

 the College received, for trial, a quantity of a material called by the manufacturers, 

 ' London purple,' and designed to be used for killing the Colorado potato beetle 

 (the potato bugs of common parlance) . Upon trial it was found to be valuable, 

 killing the old as well as the young insects with great certainty. The virtue of Lon- 

 don purple lies in the arsenic which it contains, just as in the case of Paris green. 

 There are, however, several advantages possessed by the new poison over the old, 

 among which are, first, its extreme fineness, permitting it to be mixed with water ; 

 second, its adhesiveness ; when once applied it adheres tenaciously to the leaves, 

 this is due, no doubt, to its finely divided condition ; third, its purple color enables 

 one always to detect its presence on leaves, even when it exists in but very small 

 quantities ; this will not only guard against accidents, but at the same time be of 

 considerable account in enabling one to always know when it is necessary to make 

 another application ; fourth, its cheapness as compared with Paris green ; it will be 

 impossible to say just what the cost per pound will be, until a considerable quantity 

 has been brought into our markets ; it will, however, in all probability not be more 

 than one-fourth that charged for Paris green. The London manufacturers are now 

 making arrangements for putting into the market a sufficient quantity for use upon 

 the crop of beetles in 1879. They propose to designate some firm in Des Moines to 

 take charge of the matter of introducing it. "When it becomes available it will be 

 well for our potato growers to give London purple the attention it deserves." The 

 College Quarterly, Iowa Agric. College, Ames, Iowa, Vol. i. No. iii. Sept. 

 1878, 49. 



