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JOURNAL OF HORTICULTURE AND COTTAGE GARDENER, 
May 9, 1835, 
page 372 ? and would our mental food-providers reproduce it on these 
pages? Or is it doomed to remain in that “remote village on the 
Trent.” It should be useful. Wants a good deal of manning (2) though 
—and womaning (4), besides the boy = 7, with the “ Missus” looking on 
(total. 8), and being only a machine “cannot discriminate” and sort out 
the faulty tubers. _ 
I have a friend in London who tells me that he knows a machine 
which does discriminate, for when it is corking bottles of wine in Mr. 
H. R. Williams’ gigantic stores in Lime Street, and gets hold of a bad 
cork, it throws it aside in disgust, not one in a thousand passing in a faulty 
state. London again 1 But I must cut it short, or I shall be making 
the Editors “ corky,” as wine does not, I think, make glad the hearts of 
many gardeners, so snap goes— Saynoe. 
ARGON. 
In reply to Mr. W. Dyke, page 388,1 beg to say that I gave argon on 
page 333 as an air-derived element on the “ authority ” that there is 
frequently a discrepancy in the results obtained in ascertaining the 
density of nitrogen gas procured from the atmosphere, plants and 
animals, which leads to the conclusion that some unrecognised element 
must be present to account for the discrepancies in the calculation. To 
this Mr. Dyke replies—“ It will not do to assume that because argon and 
nitrogen are found so intimately connected together that they must con¬ 
sequently be both taken up by the plant.” This is ignoring the fact 
(for there is nothing assumed) that the newly discovered constituent 
of the atmosphere “ argon ” by Lord Rayleigh, and almost immediately 
confirmed by Prof. Ramsey, was indicated by Cavendish in the last 
century as a disturbing element in the nitrogen gas derived by him 
from the atmosphere, Cavendish discovered the peculiar properties of 
hydrogen, and the qualities by which it is distinguished from atmo¬ 
spheric air. To him we owe the important discovery of the composition 
of water. Scheele had already observed that when oxygen is mixed 
with double the quantity of hydrogen, this mixture burns with an 
explosion without any visible residuum. Cavendish confined both 
gases in dry earthen vessels to prevent the escape of the product of 
their combustion, and found that the residuum was water, the weight 
of which was equal to the sum of the weight of the two gases. Priestley 
observed that a quantity of atmospheric air confined in a tube through 
which the electric spark was transmitted, lost in volume, and formed an 
acid which reddened the tincture of litmus. Cavendish took up this 
cue, confining in the tube a solution of pure potash, which absorbed the 
acid, and he proved it to be nitric acid. The analysis of the air which 
remained in the tube after the experiment showed that the weight of the 
oxygen and nitrogen which had disappeared was equal to the weight 
of the acid thus formed. He easily determined the proportion of the 
nitrogen to the oxygen, which was 2 ; f. It was found, also, that when 
both gases, sufficiently pure, were mixed in that proportion, and exposed 
to the electric spark, the mixture disappeared entirely, by which his dis¬ 
covery was completely confirmed. 
Thus Cavendish* acquired distinguished rank among those learned 
men who have most contributed to the progress of chemistry, and it is 
due to him that Lord Rayleigh and Professor Ramsey have been able to 
account for the discrepancies in the results obtained in ascertaining the 
density of nitrogen gas by the discovery of argon, the existence of which 
had been indicated by Cavendish in the last century. Numerous 
experiments were made to test the validity of Cavendish’s hypothesis; 
in fact, all chemists acknowledge that there is some unrecognised 
element present in the nitrogen gas as derived from air, plant and 
animal analysis, and that element as regards air has been shown by 
Lord Rayleigh to be argon. This element is not yet proved simple, 
some having doubt as to whether there are not two substances in com¬ 
bination rather than one only. One thing only is certain, the newly 
discovered element (if it be one and not a compound) does not combine 
with any other element, which is fatal to the mixture doctrine, but 
there are other reducing agents in the world besides chemicals, such as 
the micro-organism which converts the free nitrogen of leguminous 
plants into assimilable, and it is a notorious fact that Clover fields in 
blossom produce an atmosphere largely laden with ozone, as indicated 
by the so-called sulphurous odour, and belongs to something developed 
in the atmosphere by electricity. It is a colourless gas, unknown in a 
pure state, but hitherto has only been obtained mixed with several 
times its weight of air or oxygen. 
Its properties are oxidising ; in fact, “ ozone is nothing more or less 
than oxygen in a peculiar active condition ”—(Johnson, “ How Crops 
Feed,” page 64). (jzone is formed by chemical action as well as 
electrical disturbance, and is due to the union of oxygen with phosphorus, 
if indeed it is not formed by the oxidation of every oxidable substance, 
a portion being diffused—that is, of the oxygen in the peculiar active 
condition—into the atmosphere through escaping immediate oxidation. 
Sir J. B. Lawes, Sir J. Gilbert, and Pugh found no such evidence ; but is 
that conclusive that plants do not evolve ozone as well as oxygen from 
the foliage, and especially flowers, when acted on by sunlight ? There 
is little or none of it in crowded cities, less in slums, and the vicinity of 
manure heaps, as it there finds organic matters, and combining therewith 
its presence cannot become manifest. 
Nitrogen is a colourless, inodorous, tasteless, uncondensable gas, 
existing free in the air, the intercellular spaces of leguminous plant cells, 
and the air bladders of fishes. In combination with other elements it 
constitutes many minerals and a great variety of animal and vegetable 
substances. Lavoisier gave this substance the name of azote (Greek, a, 
privative ; zoe, life), because it is incapable of supporting life ; but 
Chaptal gave it the name by which this gas is now known because of its 
entering into the composition of nitre (nitric acid). It is readily 
obtained from the atmosphere by removing the oxygen, which may be 
done by burning phosphorus in an enclosed space of air or by passing 
air over heated copper. In doing this there is a discrepancy in the 
weight of nitrogen, and in ascertaining to what this discrepancy was 
due Lord Rayleigh discovered the gas suspected by Cavendish, and to 
which the name of argon has been given. It is what? Anything 
more than inert nitrogen 1 Surely, Mr. Dyke has authority for his 
negative statement, and will be able to supply the necessary information. 
This is essential before we proceed to explain “ how it is assimilated by 
plants.” What evidence have we that argon is but a form of nitrogen t 
Professor Ramsey’s experiments are based on the principle that the 
process which liberates nitrogen also sets free argon, which is very 
suspicious of there being only a technical difference between nitrogen 
and argon, the latter corresponding to the ozone form of oxygen. The 
Peas and mice subjected by Professor Ramsey to experiment for the 
discovery of argon in nitrogenous vegetables and animal tissues are far 
from conclusive ; indeed, it was Dumas’ method for extracting nitrogen, 
the powdered Peas or mice being mixed with copper oxide and lead 
chromate in a heated tube, whereby the hydrogen, oxygen, and carbon, 
are removed and the nitrogen is collected. Was there no indication in 
the weight of this nitrogen of another element—to wit, argon—ex¬ 
tremely inert nitrogen ? Professor Ramsey is silent about this, even 
doubting that the process adopted was not suitable for detecting the 
new element. 
Surely we ought to be satisfied with Lord Rayleigh’s and Professor 
Ramiey’s statements, and not as physicists raise the question. Do plants 
assimilate argon ? First, let chemists tell us that it has been detected 
in nitrogenous vegetables and animal substances, as Sir J. B. Lawes and 
Sir John Gilbert found there was more nitrogen in leguminous plants 
than could be possibly derived from the soil. Then and not till then 
may we set to work and prove that argon is present in plants for pre¬ 
venting that decay or impairment of tissue which must otherwise 
attend over-assimilation of the free nitrogen of leguminous plants by the 
microbes. Thus it would not be a matter of assimilation, but of insuring 
the general slowness of the fixation of free nitrogen in leguminous plants 
in symbiosis with microbes. 
The probability is that plants do not possess the power of assimilat¬ 
ing argon any more than the free oxygen, hydrogen, and nitrogen gases, 
but that is no reason why they may not absorb argon as well as the 
other elements, including carbon, and because free nitrogen is fixed by 
leguminous plants in symbiosis with microbes there is no cause to 
assume that argon must be assimilated, even if it does enter into the 
composition of plants, and of which there are certain indications. It may 
not, however, be possible to detect it at present through the method 
employed being at fault, but chemists will sooner or later make all clear 
in respect to this interesting discovery. 
The chemical constituents of the atmosphere must enter into the 
composition of plants. Evolution points to a primitive atmosphere of 
absolutely pure nitrogen, there not being any free oxygen, and with only 
such carbonic acid and water as were evolved from volcanoes, which 
extended over the greater part of the earth’s surface, the first organised 
beings came into existence. Only plants of the Algte class could then 
exist, animals being unable to subsist in such atmosphere. In course of 
time enough oxygen would be evolved oy vegetation for the support of 
animal life of a low order, and as vegetation extended there would be 
both nutrition and air enough for the support of higher forms of 
animated beings. The struggle, therefore, would be between oxygen 
on the one hand and nitrogen on the other. Micro-organisms acted 
in behoof of vegetation—the more nitrogen appropriated the more 
oxygen liberated, and the more of that the greater the fixation of 
carbon. This implies more animals subsisting directly or indirectly 
upon vegetation, and so on up to the present time. Up to a certain 
geological period there would be little or no ozone, but it would appear 
with the spread of vegetation on the land, for there could be no ozone 
evolved by marine plants. This ozone is simply a peculiarly active form 
of oxygen, and there is evidently a counterbalancing incomhinable 
element—an evolution from or a primitive form of nitrogen. Will Mr. 
Dyke kindly tell us what he knows on this subject ? It will fill up the 
gap between now and when further investigations are concluded in 
respect of argon.—G. Abbey. 
EXAMINATION IN HORTICULTURE. 
In reply to “ H. 0. H.” (page 380) I wish to say I omitted the last 
few words of the paragraph becaus? I considered there was nothing of 
any importance in them. I quite agree with him that a certificate for 
the successful culture of some kind of fruit, flowers, or vegetables, is an 
advantage to its possessor ; but to gain such is not practical to gardeners 
generally. Your correspondent on the same page asks, “ Why give a 
certificate for a thing which of itself is perfectly useless ? ” And yet 
when he is speaking of theory lower down the article he says. “ Nay, 
I commend it, for what gardener is perfect without it ? ” If “ H. 0. H.” 
thinks that the questions set at the examination are all theory, he is 
mistaken, and for the benefit of those who have never seen them I have 
* Messrs. BUckie’s “ The Popular Eucyclopeedia,” half vol, ill., page 189, 
