EFFECT OF ILLUMINATING GAS AND ETHYLENE 
UPON FLOWERING CARNATIONS 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 116 
WILLIAM CROCKER AND LEE I, KNIGHT 
(WITH FOUR FIGURES) 
1. Historical 
As early as 1864 observations were recorded on the effect of 
illuminating gas on vegetation. GrRARDIN (1) called attention to the 
phenomena of gas injury to trees as reported from various places in 
Rouen, Berlin, Hamburg, Hanover, etc. He especially investigated 
injury done to Italian poplars which had come into use as shade 
trees along the highways. He made a chemical analysis of samples 
of soil taken three feet from leaks in the gas pipes, and found inflam- 
mable oil as well as sulfur and ammonia compounds present. 
R. VircHow (2) expressed an opinion that coal gas is especially 
injurious to vegetation. Kny (3) was one of the first to test the 
injury experimentally. He used three sound trees in the Berlin 
Botanical Garden, each about twenty years old—one maple and two 
lindens. Gas pipes were carefully laid 84°™ deep and the gas used 
was freed of sulfuretted hydrogen. The two pipes were laid in a 
circle about the maple, and four burners were attached at a distance 
of 118°" from the trunk. Near each linden tree were two burners, 
tro" from the trunks. The gas escape was measured daily. 
(t) Maple received daily.................-- 12.9 cubic meters 
(2) First linden 2g ee 11.7 cubic meters 
(3) Sectind tinditcc: 4 cue eas 1.6.cubic meters 
The experiment was begun July 7 and lasted for (1) and (2) a half- 
year, for (3) a full year. First a Euonymus (E. europea) near the 
maple died, then the maple lost its leaves (September 1). At the 
same time an elm near by showed injury. September 30 the first 
linden showed signs of injury. On October 12 the first linden lost 
ts leaves, and on October 19 the second, while other lindens in the 
8arden were yet green. An examination of roots one-half inch in 
diameter showed a blue coloration extending out from the middle 
59] [Botanical Gazette, vol. 46 
