244. M. A. de Candolle on Germination 
regard to heat, of the isolation of the reservoir. The box was 
placed in an arched deep cellar, having no other outlet than a 
door opening into a vault. The temperature was therefore na- 
turally very steady, at least entirely removed from the influence 
of daily and even weekly variations. 
The temperatures near 0° were maintained with steadiness in 
the reservoir as long as I wished, by renewing the ice every three 
days; but in the case of other temperatures, especially from 
18° upwards, the apparatus was unsatisfactory. Water at 
50° or 55° very rapidly loses its heat ; and the apparatus being 
difficult to move, I gave up its use, preferring to take advan- 
tage of the succession of the seasons for placing the sowings 
sometimes in the cellar, at others in the open air, then in rooms 
or cupboards where the temperature scarcely varies from day to 
day, which has allowed me to continue the observations to about 
somewhat less than 24°; and for the higher degrees, I had re- 
course to the artificial heat of a lamp. 
Temperature of 0°. 
Three small vessels to contain the sowings of the seeds were 
placed in a large glass bottle closed with a cork. This floated in 
the reservoir of melting ice, without ever entirely emerging or 
becoming submerged. The temperature of 0° was maintained in 
the interior of the apparatus with remarkable steadiness. Even 
when a somewhat larger proportion of ice than usual was allowed 
to melt, the thermometer immersed in the vessels containing the 
seeds indicated exactly 0°. Another cylindrical box, made of 
tin, which floated in the same reservoir and contained some 
sowings, also retained the temperature of O° with great steadi- 
ness. 
The experiment lasted from 4 o’clock on the 7th of March 
until the same hour on the 11th of April, 7. e. thirty-five days. 
The results in the case of ten species are subjoined*. 
The following did not germinate at all :—Collomia, Lepidium, 
Linum, maize, the melon, Nigella, Sesamum, Trifolium, and 
Celosia. 
Two sowings were made of Trifolium, one in the vessels con- 
tained in the large bottle, the other in the tin box. 
The only species which germinated was the Sinapis, of which 
also two sowings were made, one in the bottle, the other in the 
box. Of the former, some seeds (five out of thirty) germinated 
from the 28rd to the 25th of March, the mean being the seven- 
teenth day. In the box, in which the sowing only took place on the 
* The Iberis was not sown in some of my experiments, one of the 
Amaranthacee (Celosia cristata) beg substituted for it. 
