1918] Goodspeed^McGee-Uodgson: Effects of Illuminating Gas 441 



(c) Hydrogen — electrolytically by electrolysis of distilled water 

 containing sodium hydroxide, then passing through a tube containing 

 soda lime and fused calcium chloride. 



(d) Methane — treating sodium acetate with soda lime and washing 

 by bubbling through strong sodium hydroxide solution. 



(e) Ethylene — dropping ethyl alcohol (95%) into cone. c. p. phos- 

 phoric acid which was kept at a temperature of 210° to 220° C and 

 washing by bubbling through cold cone, sulfuric acid and finally pass- 

 ing through a large U-tube filled with soda lime. 



In the experiments with Citrus large dessicating dishes with ground- 

 glass covers were used. In these containers flower-bearing shoots were 

 placed and illuminating gas introduced. The reported percentages of 

 gas used in this case (cf. table 1) are only approximations and were 

 not quantitatively correct as in the corresponding experiments with 

 Nicotiana. The controls were run in large moist chambers. Citrus 

 sinensis varieties Washington navel and Valencia and Citrus limonia 

 var. Eureka, growing in the greenhouses of the University of Cali- 

 fornia, were employed in the experiments. 



III. EESULTS 

 The results of the experiments to determine the effect of various 

 percentages of illuminating gas in causing flower-fall in Nicotiana and 

 Citrus are summarized in the following table. 



Table 1 



Effects of Various Percentages op Illuminating Gas in Causing Flower- 

 fall IN Nicotiana and Citrus 

 The figures given represent the times in hours between the start of 

 the experiment and the fall of the first flower 



