Entomological Notes. 279 



to expose the flowers to moisture, or the rajs of the sun, or, still 

 less, to artificial heat. They should be dried under cover and 

 hermetically closed up in sacks or other vessels to prevent un- 

 timely pulverization. The finer the flower heads are pulverized, 

 the more effectually the powder acts and the more economical is 

 its use. Proper pulverization in large quantities is best done by 

 those who make a business of it and have special mill facilities. 

 Leon & Fink, of New York, have furnished us with the most 

 satisfactory powder. For his own use the farmer can pulverize 

 smaller quantities by the simple method of pounding the flowers 

 in a mortar. It is necessary that the mortar be closed, and a piece 

 of leather through which the pestle moves, such as is generally 

 used in pulverizing pharmaceutic substances in a laboratory, will 

 answer. The quantity to be pulverized should not exceed one 

 pound at a time, thus avoiding too high a degree of heat, which 

 would be injurious to the quality of the powder. The pulveriza- 

 tion being deemed sufficient, the substance is sifted through a silk 

 sieve, and then the remainder, with a new addition of flowers, is 

 put in the mortar and pulverized again. 



"The best vessels for keeping the powder are fruit jars with 

 patent covers, or any other perfectly tight glass vessel or tin box." 



In a later article Prof. Eiley treats of 



Its use as an Insecticide. — Up to a comparatively recent 

 period the powder was applied only to the destruction of those in- 

 sects that are troublesome in dwellings, and Mr. C. "Willemot 

 seems to have been the first to point out its value, when used 

 against insects injurious to agriculture and horticulture. He goes, 

 however, too far in its praise, especially when claiming that sowed 

 with wheat it will prevent the ravages of/the weevil. During the 

 last three years we have experimented with it on many species of 

 injurious insects, and fully appreciate its value as a general in- 

 secticide, which value has been greatly enhanced by the discovery 

 that it can be most economically used in liquid solution, but we 

 are far from considering it a universal remedy for all insects. No 

 such universal remedy exists, and Pyrethrum. has its disadvan- 

 tages, the same as all other insecticides now in use. The follow- 



