October 14,1880. ] JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 355 
been attributed to “ the damp ; ” but this alone will never suffice, 
for it is well known that wooden posts and timbers and ancient 
canoes have lain for centuries buried within the earth, and when 
subsequently exhumed have been as solid as they were at first. 
As suggested by Faraday, “ we must infer the unknown from the 
known.” Trees and plants being situate in precisely the same 
manner—part in the damp earth and part exposed to the atmo¬ 
sphere—it is therefore a legitimate inference that a similar result 
must follow. Every gardener knows full well that the collar or 
neck of a plant which forms at this meeting of the air and the 
earth is the vital part of the plant, and where it is most easily 
killed, and which is thus explained ; it is here that the food is 
converted into sap, which sap then flows upwards and becomes 
distributed all over the plant. 
In the grammar of physical science there are various laws and 
rules that are never infringed, but are invariably followed to the 
letter; thus, in electro-chemical action fluids are always passed 
to the negative. In the decomposition of water oxygen invariably 
makes its appearance at the positive, whilst hydrogen is evolved 
at the negative. Alkaline salts, metallic deposits, and crystal¬ 
lisations of every description form at the negative ; but acids, being 
Fig. 64. 
Fig. 65. 
Fig. 66. 
negative, accumulate at the positive electrode. The distinction 
between electro-chemical and ordinary chemical action is that in 
the former the resulting compound is attracted and drawn away 
from the point where it was formed to some other locality, as in 
the sulphate of copper being repelled upwards ; but in ordinary 
chemical action, as in the mixture of an acid with an alkali, the 
combined elements remain where they are placed, there being no 
attracting, or repelling power to enable them to shift their posi¬ 
tion, moisture in all cases being indispensable. 
Respecting the nature of electricity this, from whatever source 
it may be derived, is always the same. It has this peculiarity, 
that in its active state it consists of two opposite forces, like one 
force polarised or divided into two; the attracting power being 
confined between themselves, each one repelling its like. Scrape 
some sealing wax on to a piece of paper, and then rub the same 
piece of wax on the coat sleeve, and although it will then attract 
small feathers or scraps of paper, it will have no attraction for its 
own scrapings, because they are of the same electric condition as 
itself. 
By the law of induction, like magnetism inducing magnetism, 
it is impossible to have one condition of electricity without the 
other being present in like proportion of quantity and intensity. 
This is a very important point to be remembered, as it constitutes 
a leading principle in most of the phenomena of life and culture. 
Thus, if we excite increased action at the roots, an equally in¬ 
creased action in the plant must follow of necessity provided the 
plant be in a condition capable of responding, otherwise, like the 
excess of oxygen upon the seeds and from rusting iron, the 
balance will be destroyed and death speedily follow.. Then, again, 
whenever an electrical condition is thus induced, it is always of 
the opposite character to that by which it was so induced. From 
this law of induction, and the earth being negative, the atmosphere 
becomes normally positive. These two relative conditions are 
essential to vegetation, or, if both be positive or both negative as 
was the atmosphere and earth in the plant-case previously alluded 
t@, ordinary plants cannot possibly flourish ; but a different 
character of growth altogether makes its appearance. As this, 
however, belongs more especially to the production of mildew 
and the cultivation of Mushrooms, &c., it must therefore be left for 
the present. 
In order to enable us to comprehend the way in which oxygen 
is made subservient at the collar of the plant, it will be needful 
to explain the precise manner of its operations in connection with 
the copper wire. The lower portion of the latter, by its immersion 
in the negative acid, is at once rendered positive, whilst the upper 
portion by the positive atmosphere surrounding it is at the same 
time rendered negative. The next step is that this upper negative 
portion becomes damp on its surface as previously stated. The 
wire, being positive under the part so wetted, attracts and com¬ 
bines with the oxygen from the atmosphere, when the thin film of 
acid immediately dissolves and becomes saturated with it, and in 
its journey upward deposits it in crystallisation. It will be ob¬ 
served that the copper wire, after it has been a long time in the 
acid, has been less and less acted upon in proportion as it becomes 
more deeply immersed, and consequently further from the air- 
surface. This fact affords a good illustration of the advantage of 
roots being near the surface so as to be well within atmospheric 
influence. 
In the rotting gatepost we have a corresponding action, but 
with somewhat varied results. The union of the oxygen with the 
carbon of the wood produces a soluble compound—carbonic acid ; 
but which, not being crystallisable by ordinary means, and there 
being no organisation going on in the wood to effect its utilisation, 
it disappears into the atmosphere, and the post becomes lessened 
in its bulk imperceptibly, and without the usual discoloration of 
ordinary decay. In the latter it is the carbon that is left; but 
in this case it is the carbon itself that is appropriated and carried 
away by the oxygen, but which in the plant is absorbed and 
carried into the system. There is, however, another special 
arrangement for accomplishing this end in the best way. Instead 
of the fluid being carried up on the outside of the stem, as it is on 
the exterior surface of the copper wire, and where in the plant it 
would speedily be dried up by the sun and the wind, provision is 
made for its passing up inside among the cells and tissues within. 
Procure a few seedlings of any kind, from a half to an inch or 
more in length, and wash them for a minute or less m water 
coloured with a few drops of Judson’s magenta dye, and then 
having rinsed them in clean water place them in a drop of water 
between two pieces of glass, and if they be now examined with a 
pocket lens it will be seen, that whilst the stain has almost 
instantly coloured the roots strongly, the colouring ceases abruptly 
at the neck or collar, and is then only very slowly absorbed in 
streaks and lines into the stems and leaves. There will thus be 
an abrupt division between the parts within the soil on the one 
hand, and those above it exposed to the atmosphere on the other. 
This process of staining is a most delicate test for chemical 
affinities or otherwise of electrical condition. The dye takes 
readily in all negative fluids, whilst it is rejected by all such as 
are positive. Let it be applied to the seed in its earliest stages of 
germination, and it will be found to be equally demonstrative, 
showing that the seed has a polar construction, and hence it is 
that it was enabled in the experiment with Cress seed to respond 
to the electric influence when reversed, and was thus compelled 
to an inverted position, or heels upwards. The roots are here 
shown to absorb readily an oxygenated pabulum and to pass it 
onwards ; but the cross-action at the collar causes it to unite 
with other matters thus introduced and to become nutrient sap, 
so that it thus leaves this part in a different state to that in which 
it entered at the roots. If a seedling be grown in sand or in 
crushed brick, its rootlets when pulled up will be found clinging 
to the grains in clusters. Liebig has spoken of stones found in 
Wheat fields whose surfaces are covered with minute grooves, 
and in some instances near the roots of trees these grooves have 
been occupied by rootlets. Now these rootlets are strictly 
feeding upon the mineral, and have been the agents in electro- 
chemically dissolving out the said grooves. Flint glass and the 
most insoluble substances can be acted upon thus very readily by 
the battery, and when it is remembered that many or most of the 
tissues of plants are thickly studded with crystals of lime, or 
“ raphides,” and the stems of canes and grasses are covered with a 
coating of silex or flint, it is easy to see where and how the plant 
has acquired them. 
Place a strip of bone, such as the handle of an old toothbrush, 
in acid instead of the copper wire, and it will undergo a very 
similar change. The lime will soon begin to appear above the 
acid, and crystallise upon the exposed surface. But there is another 
peculiarity. On the side away from the light the lime will travel 
much higher up than it does on the side exposed to the light, a 
fact quite in accordance with Nature. Oxygenation and the pro¬ 
duction of sap, or in fact the growth of a plant, takes place chiefly 
at night or in the dark, just as the digestion of our food and the 
production of chyme, manufactured in our stomachs, is carried on 
in the dark. 
