Distribution of HCN Gas in Greenhouse Fumigation 11 



these fumigations were made is well brought out. It will be 

 noted in every case in which fumigations are carried out in the 

 so-called fern greenhouse that the concentration of gas tended 

 to be the greatest on the right-hand side of the house. The 

 cause of this peculiar distribution is not known, but it is sur- 

 mised that temperature may have had something to do with it, 

 as the right-hand side of the house was shaded during the day, 

 and hence would be cooler. The bearing of such a distribution 



/zj-^jre? es/o///2 



MINUTZ5 



Fig. 4. Graph of Fumigation No. 4 



A, center bench; B, middle bench; C, outside bench; D, comb 

 collecting tube; E, center collecting tube; F, middle collecting 

 tube; G, outside collecting tube. 



of gas as is shown in this greenhouse upon the burning of the 

 plants and the killing of the insect is obvious. 



Distribution in Relation to Dosage 



In considering distribution in relation to dosage many pe- 

 culiar things arc noted. In the first place, the great concentra- 

 tion of gas in the comb is not so noticeable with the smaller 

 charges as it is with the larger. A comparison of figures 3 and 

 4 with figures 13 and 14 will show this plainly. This difference 

 is probably due to the difference in amount of the chemicals 

 taking part in the reaction. More heat is generated with the 

 greater charge and thus the gas would tend to expand and rise 

 more quickly than if less heated. 



