315 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, February 15, 1859. 
suitable temperature to atmospheric air, it absorbs the oxygen 
only. This power of separating one gas from the others, appears 
to reside in the skin of the seed, for old seeds lose the power of 
absorbing the oxygen, and, consequently, of germinating; yet 
they will frequently germinate if soaked in a solution of chlorine 
in water—a gas which has the power of attracting hydrogen from 
its compounds, and releasing the oxygen, doing so in the case of 
seeds within their skin, as well as without. Humboldt and 
Saussure have also shown, that the application of chlorine to seed 
accelerates its germination ; and Cress seed, which, under ordinary 
circumstances, requires some days to complete the process, they 
found effected it in no more than three hours. 
The late Mr. George Sinclair, author of the excellent “ Hortus 
Gramineus Woburnensis,” informed us that he employed chlorine 
with singular success. He obtained it by mixing a tablespoonful 
of muriatic acid (spirit of salt), with a similar quantity of black 
oxide of manganese, and half a pint of water. After allowing the 
mixture to remain two or three hours, the seed is to be immersed 
in the liquid for a similar period, and then sown. Another, and, 
we consider, the most eligible mode of applying the chlorine, was 
also suggested to us by the same distinguished horticulturist. 
In this way, he said, he made tropical seeds vegetate, which 
refused to germinate by other modes of treatment. He placed 
the mixed ingredients, mentioned above, in a glass retort, in¬ 
serting it3 bulb in the hotbed, and bringing its beak under the 
pot in which the seeds were sown, connecting it with the draining 
aperture of the pot. The chlorine gas is gradually evolved, 
passing through the earth of the pot to the seeds, accordingly 
as the heat required for the different species induces. 
We are indebted to M. de Humboldt for a number of very 
curious observations on the property which chlorine possesses of 
stimulating, or favouring, germination. The experiments of M. 
de Humboldt were made in the first instance, on the common 
Cress (Lepidium sativum). The seeds were placed in two test- 
tubes of glass, one of which contained a weak solution of chlorine, 
the other common water. The tubes were placed in the dark, 
the temperature being maintained at about 59°. In the chlorine 
solution, germination took place in six or seven hours; from 
thirty-six to thirty-eight were required before it was manifest in 
the seeds in the water. In the chlorine, the radicles had attained 
the length of 0.0585 Eng. inch, after the lapse of fifteen hours, 
whilst they were scarcely visible at the end of twenty hours in 
the seeds submerged in water.—( Flora Fribergensis subterranea, 
p. 156.) 
In the botanical gardens of Berlin, Potsdam, and Vienna, this 
property of chlorine has been made available to excellent ends; 
by its means many old seeds, upon which a great variety of trials 
had already been made in vain to make them sprout, were brought 
to germinate. At Schoenbrunn, for instance, they had never 
succeeded in raising the Clusia rosea from its seed ; but M. de 
Humboldt succeeded at once, by forming a paste of peroxide of 
manganese, with water and hydrochloric acid, in which he set 
the seeds of the Clusia , and then placed them in a temperature 
of from 143° to 167°. 
This absolute necessity for the presence of oxygen, is a reason 
why seeds will not germinate if buried beyond a certain distance 
from the earth’s surface; and why clayey soils often fail of 
having a good plant—an impervious coat of the clay enveloping 
the seed, and preventing the air’s access. 
M. Burger found that seeds of Rye, buried one inch below the 
surface, had their leaves above it in eight days and a half; whereas 
those at a depth of six inches, had only just sprouted at the end 
of twenty-two days. 
But too-deep sowing inflicts another injury ; though it be not 
at such a depth as to entirely prevent germination, it so con¬ 
sumes the matter of the seed in forming the useless elongation 
of stalk necessary to bring the leaves above the surface, that all 
further progress in vegetation has been prevented. M. Burger 
found that Rye seeds sown five inches and a half deep, forced 
their blades to the surface in seventeen days and a half, but these 
remained green only for six days and then withered; and that in 
every instance, the most shallow-sown seeds produced the most 
stalks. We have observed the same in the case of Kidney Beans, 
Windsor Beans, and Peas of various varieties ; those seeds buried 
one inch and a half below the surface, invariably grew higher 
and were more prolific than those buried at double or even greater 
depths. 
From Saussure’s experiments we learn that, weight for weight, 
Wheat and Barley, during germination, absorb less oxygen than 
Peas; whilst these consume less than Beans and Kidney Beans. 
This explains why, in proportion to their size, the two first may 
be sown at a greater depth below the soil’s surface than the three 
last named, without vegetation being prevented. 
It is chiefly the want of a due supply of oxygen that forbids 
seeds germinating, which are buried at great depths ; seeds thus 
deposited, or similarly excluded from the air in the Egyptian 
mummy cerements, will often retain their vegetative power for 
an apparently unlimited time. Hence, earth taken from far 
below the surface will often become covered with Charlock. This 
is an oleaginous-seeded plant; and such, when thus excluded from 
the air, retain their vitality most pertinaciously for reasons already 
assigned. 
There are some seeds, Peas for instance, and the seeds of 
aquatic plants, which have the property of germinating under 
water. Some observers have, from this fact, come to the erroneous 
conclusion that atmospheric air, and consequently oxygen, were 
by no means necessary to germination. Saussure has explained 
this anomaly by referring to the constant presence of air in a 
state of solution in water. In fact, having placed some seeds 
of the Polygonum amphibium under water, deprived of its air by 
long-boiling, Saussure proved that germination could not take 
place.— (Recherches chimiques, fyc., p. 3.) 
Under like circumstances, the quantity of carbonic acid 
generated in a given time, is by so much greater, the larger the 
quantity of oxygen in the atmosphere which immediately sur¬ 
rounds the germinating seed. Carbonic acid gas is of all the 
gases which have been tried, that which is most unfavourable to 
germination ; and one way of hastening the process, is to place, 
under the receivers which cover the seed, some substance capable 
of absorbing that gas as fast as it is formed—quicklime, for ex¬ 
ample. By this arrangement, the growth of the rootlet is sensibly 
accelerated.— (Idem, p. 26.) 
Inasmuch as seeds during germination yield carbonic acid to 
the atmosphere, it is quite obvious that they must lose some part 
of their original weight. And this they do, in fact; but the loss 
experienced by seeds which have germinated, is always greater 
than that which would have resulted from the removal of carbon 
which takes place. Saussure attributed this excess of loss to the 
volatilisation of a portion of the water which entered into the 
composition of the seed.— (Idem, p. 20.) According to Saussure, 
therefore, the phenomena of germination resolve themselves into 
the diminution of carbon, and of the elements of water. It is, 
nevertheless, doubtful whether the chemical actions are so simple 
as this : we know, for example, that 51. Becquerel considered the 
acid which appears during germination, as acetic acid. There 
is certainty of the formation of an acid during germination ; to 
prove its development, it is sufficient to make a few moist seeds 
sprout on blue litmus paper, which speedily acquires the per¬ 
manent red indicating the presence of an acid; and if seeds whilst 
sprouting are surrounded by lime, in powder, it is converted into 
acetate of lime. 
So far are plants at their first germination from being benefited 
by the application of stimulants, as is supposed by the advocates 
of those menstrua, that if the air supplied to them during that 
process, is contaminated by stimulating vapours, such as that of 
sulphuric setlier, camphor, spirits of turpentine, or ammonia, 
germination is always in some degree retarded and injured. 
How oxygen operates in aiding the seed to develope the parts 
of the embryo plant we cannot even guess—we only know that 
most seeds have more carbon (pure charcoal), in their composi¬ 
tion than other parts of their parent plant; that the oxygen 
absorbed by the seeds, combines with a portion of that extra 
carbon, and is emitted in the form of carbonic acid. These are 
the attendant phenomena, but we can penetrate the mystery no 
farther.—J. 
(To be continued.) 
TO CORRESPONDENTS. 
IiAi.N'-WATKft Cask (J. H. C .).—We recommend you to char the inside of 
the gas-tar cask before you use it for this purpose. Coal ashes are the dust 
remaining after the coui has been burnt. Did you ever hear of any ashes 
that did not imply a previous burning ? 
Tan as a Mui.ru for Strawberries (An Old Subscriber).— It has been 
often used to keep in the moisture of the soil, and to save the berries from 
being rain-splashed. No solvent for leather is known. Sulphuric acid is 
the best fixer of ammonia in liquid manure. 
Conservatory Climbers i J. Thanks for the sight of the crossed 
Veronica. It must make a beautiful evergreen, somewhat like the 
Minorca Box, when not in bloom. As for extra-fine climbers for the con¬ 
servator!', there are no new ones, nor for growing in a warmer house, or 
