14 N. J. Agricultural Experiment Stations, Biilijetin 355 



was done in the same house, and with the same charge, and 

 likewise higher than those found in No. 9, which was done in 

 the fern greenhouse, which had a capacity of y/2 times the small 

 propagator house in which No. 5 and 7 were performed. Thus 

 it seems that the tightness or looseness of the individual house 

 plays a much more important part in determining the rate of 

 loss and consequent concentration, than does the size of the 

 house. In other words, a small house tightly glazed will retain 



c Id £ 





house: 



FLAN 



CAPACITY 

 J,37l cu.-ft 



O Z ^ 6 8 10 la 14 16 IQ £.0 ££. 24 £6 23 30 02 34 36 



Fig. 7. Graph of Fumigation No. 7 



A, left bench; B, right bench; C, left collecting tube; D, 

 center collecting tube; E, right collecting tube; F, comb collect- 

 ing tube. 



a greater portion of the gas generated in a fumigation than a 

 large house which may have less surface in proportion but which 

 is less tight. 



Distribution in Relation to Temperature 



So far as can be judged from the results of the tests made 

 on the fumigations, temperature has little effect upon the dis- 

 tribution of HCN gas in greenhouse fumigation. Comparing 

 the average concentrations obtained from two fumigations, at 

 the same relative times from the beginning of the fumigation, 

 it is found that with a ^-ounce charge in a greenhouse of 25,- 

 000 cubic feet capacity, for a dilTerence of 10° F. the concentra- 

 tions are uniformly lower at the higher temperature. In this 



