Qg2 
BOTANICAL GAZETTE 
[FEBRUARY 
soak seeds in the flask, and then, when one is ready, to draw off 
the water without exposing or disturbing the other contents. 
The 
efficiency of silvered double-walled Dewar flasks used as insulators 
Gord 
V 
PYG, t 
a 
Fic. 2 
is indicated by the following ex- 
periment. Four flasks, numbered 
1, 3, 4, and 6, held in pairs in 
the wooden filter stands usual in 
chemical laboratories, were set on 
a table in my laboratory. Into 
each were introduced 140 cc. of 
hot, distilled water; a long ther- 
mometer reading to tenths of a 
degree was placed in each flask 
and held, with the bulb almost 
touching the bottom, by a tight 
plug of absorbent cotton placed 
in the neck. The successive 
thermometer readings and other data follow: 
. AucusT 26, 1909 AUGUST 27, 1909) ae me 
1r:30 A.M. 1:45 P.M. 3105 pos s | II:05 A.M. 2:15 P.M 
. ff EN 2.4C. 67.05° 64.4° | a ~f 21.4 
Pa ike ff 61.75 56,7 Renee 5 ae 
Pe es 60.05 54.0 51.12 ites wed cal sepa | neue 
poe ene se 63.4 57.6 54.74 51.0 : | 20.75 
Room ar.11 20.75 21.2 20.75 | 20.75 
A similar experiment is recorded in the following table, in which 
drained flasks were used in constant temperature room A: 
APRIL 18, r9r0 APRIL 19, 1910 
FLask fasta 
II:04 A.M. 12:05 P.M. 12:20 P.M. 4:15 
Rh ass eee eerie 68. 7° 65.6° $2.4 30.2 
1 Ore, I Rae UE OU AUS Pa 92.9 69.9 38.6 36.25 
TAO ee eee os 61.1 (broke) 46.9 17:8 17.8 
a fee ee ee 51.15 49.9 30.7 28.9 
NS spi eens es bee eue 17.0 17.5 17.3 17.3 
