72 



THE MONTHLY BULLETIN. 



machine!^ is that in the one under discussion the gas is generated within 

 a small space, which may or may not result in a more complete delivery 

 of the first charge of gas as well as in the delivery of small doses. This 

 point has not been investigated, and is suggested for future study. 



Fir,. 17. — Working parts of the Buttress fumigating: macliine. 

 (Photo by J. A. Prizer, Chuhi Vista.) 



ADVANTAGES OF THE NEW SYSTEM. 



The construction of the machines almost entirely prevents "spatter.'" 

 which may be a factor in fruit and foliage injury and is certainly the 

 most important cause of acid burning of tents. 



The dose may be measured more accurately and rapidly in liquid 

 form than by weighing the solid, thereby saving material and economiz- 

 ing time. 



Convenient provision is made for the collection and removal from the 

 orchard of the strongly acid residue, which is an undesirable addition to 

 the soil and is also a menace to the tents. 



It is believed that the maximum delivery of gas is obtained on account 

 of the heat produced by the action of the acid upon the water and the 

 chemical reaction. 



The generation of the gas is very rapid and tlic tent is filled with the 

 maximum concentration of the gas before leakage becomes an important 

 factor. 



