188 
easily elapse before the analysis is made, a time which is more 
than sufficient for an utter alteration of the composition of the 
air to take place (the cause of this of course being the respiration 
of the plant). 
In order to find out whether it might be better to bring the 
roots home quite exposed to the air, I made after having been 
enabled to carry out analyses on the spot the two following analyses: 
Of Os ol, C0Og 
Air from the rhizoma of Nuphar lutea. Analysed 
ikek FB TREE SER SEA SAR HEDERNE ae HE ST LES 6,3 6,3 
Analysis of the same rhizoma 11” a. m. after having 
been exposed to the air 2 hours 25 min. ..... 20,5 0,3 
This shows plainly the absolute necessity of making the analyses 
on the spot. The following have therefore all been made in å 
boat by means of the portable apparatus. In this way at most 
15 minutes will elapse (for instance when two analyses on the 
same plant are wanted). 
When the plant, however, is kept floating on the water with 
its roots submerged, a state which as nearly as possible corresponds 
to tlie natural condition, no particular alteration will take place as 
the following analyses show. 
12/7 1914. Analysis of the intercellular air from a 
Nupbar BOE 1 0 ae AR EEN 10,8 "lo Car 
-… —  Ånalyses of the air from the corresponding 
spot on a nejighbouring root made 2 hours 
after the foregoing, during which interval 
the plant was floating on the water with 
submerged. foo 405 an. 1 v0E. sort 1 RT RåD De 
Even when a plant hås been kept floating for a day in 
this manner no appreciable alteration will take place. 
