Effect of Illuminating Gas. 



83 



EFFECT OF ILLUMINATING GAS AND ITS CONSTITU- 

 ENTS UPON FLOWERING CARNATIONS. 

 By W. M. Crocker and Lee I. Knight. 



It is quite commonly asserted that plants do poorly in 

 houses lighted with gas and that the flowering especially is 

 interfered with. Various inquiries have come to us from carna- 

 tion growers as to the effect of illuminating gas upon the flower- 

 ing carnation. These growers claimed to have had heavy losses 

 from gas that seeped from defective pipes through the ground 

 into greenhouses. In some cases it is claimed that the losses 

 occurred during cold weather, when little ventilation was possible 

 and when the ground was frozen, so that upward diffusion 

 from the defective pipes was hindered and thereby lateral dif- 

 fusion fostered. In all cases it is claimed that the injuries 

 ceased with the repair or removal of pipes. 



Various workers have found leaks in gas pipes very injur 

 ious to nearby trees. Neljubow found that it produced a pe- 

 culiar nutation in pea seedlings, especially those grown in dark 

 ness. He farther determined that a number of the constituents 

 were rather toxic and that very low concentrations of these 

 constituents (especially ethylene) were effective in producing 

 these nutations. 



It is found, however, that no accurate determinations have 

 been made upon the effects of illuminating gas and its con- 

 stituents upon flowers, and that in no case have the toxic limits 

 and the relative toxicity of the several main constituents been 

 determined. In short, it is not known in any case whether the 

 toxic limit of the gas is determined by the action of one constit- 

 uent or by the combined action of several. To answer these 

 questions is the purpose of the investigation here reported. 



A number of experiments were run to determine the toxic 

 limits of methane, carbon monoxid, acetylene, hydrogen, 

 carbon bisulfid, and benzene to the buds and flowers. As would 

 be expected, hydrogen was perfectly neutral when it completely 

 displaced the nitrogen of the air. In all the other constituents 

 here mentioned, the toxicity was such that in the least amount of 

 illuminating gas necessary to kill the bud no one is concentrated 

 enough to reach one-fiftieth of its toxic limit. It is very prob- 



