Effect of Illuminating Gas. 



87 



When open flowers were exposed to the ethylene, it was 

 found that 0.5 cc. of the 2 per cent, mixture in 20,000 (i. e., 1 part 

 in 2,000,000) caused the closing within twelve hours. The 

 result of such an experiment is shown in Fig. 4e. 



It is seen from the data given above that ethylene must 

 form from 2 to 4 per cent, of illuminating gas to be the constitu- 

 ent that determines the toxicity of the latter. It becomes neces- 

 sary now to get an estimate of the fraction of the illuminating 

 gas used that is ethylene. This was done by passing large 

 volumes of gas through bromine water, washing and drying 

 the resulting oils, and fractionating for ethylene dibromide. 

 In determinations for volumes of gas ranging from 128 to 208 

 liters the results showed 2.9 to 3.2 per cent, of ethylene. 



It is of great interest to know that the most delicate chem- 

 ical test for illuminating gas in the atmosphere falls far short of 

 detecting amounts that work havoc with the flowers of the carna- 

 tion. The tests for carbon monoxid are those used for detecting 

 illuminating gas. The most delicate application of the blood 

 test will detect 1 part of carbon monoxid per 40,000. The 

 iodine pentoxid test is of equal delicacy. If carbon monoxid 

 forms 2.5 per cent, of illuminating gas, these tests will detect 

 1 part of illuminating gas in 10,000. Upon three days' exposure 

 1 part of illuminating gas in 40,000 kills the young buds and the 

 petals of the flowers just beginning to open; while 1 part in 80,000 

 causes open flowers to close upon an exposure of twelve hours. 



The so-called "sleep" or closing of the carnation is a source 

 of considerable loss to growers and dealers, for flowers that once 

 close never open a^ain. This "sleep" is especially likely to 

 occur with cut flowers brought into city markets. Some va- 

 rieties are so disposed to react in this way that their cultivation 

 has almost entirely ceased. We know several hones lighted with 

 gas where cut carnations can be kept only a few hours without 

 "going to sleep." In one instance the displacement of gas 

 lights with electric lights entirely overcame this difficulty. Our 

 experiments show clearly that one cause of this sleep is traces 

 of illuminating gas (ethylene) in the surrounding atmosphere. 



Various investigators have shown that illuminating gas 

 diffuses great distances through the soil, especially if there is a 



