Sete ee ee a Se eo ee ee 
1842.} 
THE GARDENERS’ CHRONICLE. 405 
the haste with which Liebig has .worked, of his. striking 
want of scientific knowle edge, and of the little consi idera 
foundati oe when the d a 
weak advocate has been easily thrust aside. I feel it my duty 
to state this expressly, as many persons would otherwise 
nt of vi 
attacked Liebig on accou 
a: 
m 
0 
solve; and that at least, in this publication, he has not 
in any essential way contributed to the solution of these 
order t 
nent exam 
Gt 
The ro Scien Pe to 0 43) tre eats of the aorta 
ic acid. 
1 . 
been ua originally b y the vege- 
hem 
nese but by c 3 as is evident from 
the ‘elvomnatie that Dr. i 
Licbig,, in his short view of 
n 
ur re 
authori: ake su na 
that Dr. Liebig has not s veceded h in ‘sstablishin. what he 
ised ; but, inste ad of it, as adduced a fact which 
of col 
witho: 
In wate 
old experience that dr rought in su mmer and a high degree 
e 
the 
eabicig” whi ch feller, that cold water, 
mould only of the salts of the rain water, 
me 
and that t it remains colourless, is not t 
of ¥ assuming that (according to Schiibler) an acre 
7 receives, during a dof four months’ 
tation, 700,000 Ibs. of rain water, which reaches plants 
While saturated with that salt which is the most 
Leer ble ntains the greatest qu: of humic 
acid, #. e. with lime ; t by this, not one-sixth of 
ais ebonic acid which is prod d 
ter which is tained in the soil. ie 
a 
; and 
is always found in sufficient 1 Sg 
walochetion, whic 
t 
potash and soda do not differ from lime in their sapaotty 
ld have expected Dr. Liebig to know 
shou 
that the difference is very great. Further, he a tirely 
mmonia, which forms the salt ri i 
ca the soil, probably as a humate, being 
afterwards decomposed by the plant for the purpose of 
forming matters containing ni . y, the auth 
has not taken notice of secretion from roots, of which he 
38 elsewhere uous ad ccording to this 
__, theory, it would be probable that a great quantity o} ; 
after having given the plan are , 
 «fnsequently cannot be found in the ashes. But these 
bases can again directl saturated with humic acid, can 
thus re-enter the plant, and will then undergo again de- 
omposition and secretion, and so —_ ~ orem gee 
then, is entire] . a of all the 
fan requi 
eon the improbabity iy the theory 
culation or its 
Liebig, will show how insignificant-« such estimates 
cre contains 40,000 square feet. If the crust of soil 
snictesinie’ nm vegetation is taken to extend to the d epth of 
2 
tha t carbonic “acid i is 3 dissolved.i in a the lonver' of plants, has 
ot in any way heen proved, and he himself thinks it very 
a foot, and the specific gravity of the earth at 2.0, the acre | leaves absorb the bonic acid which is required for 
contains 4,000,000 cubic feet. Sa uppose that it contains one | the maintenance and growth of the plants fr tmo- 
per cent, of nace the humus amounts ‘to 40, 60 lbs. Ac- here t the plants, when they are perfec rmed, 
cording to Berzelius t the at are not in n the onic acid, of the soil; and that 
sphere in 24 hot s 40), 000 lbs. of water; cons sequently ii in | want of moisture and complete dryness of the soil do not 
120 days, du ~t ngs ithe period of vegetation, 4,800,000 Ibs. | impede the ompletion of their development (p. 46) ;—all 
fw o the + t added 700,000 ibs, of rain, | these propositions are mere tions, and have evidently 
with raises he quantity to 5,590,000 lbs. of water. In | been written without consideration. For com ri- 
this way the slants receive 2,200 Ibs. of lime saturated ce shews, that plants must dic if t il loses its 
wi a ic acid, whi s equal to 2,016 lbs. of humic | moisture entirely, and thus refutes the lade of the 
acid, or to 1,169 lbs. carbonic acid ow the Corn and | author in a manner which cannot be questioned. In con- 
Straw gro cre contain, dig, | ceiving this unfounded theory, he ev dently s been -in- 
1,020 lbs. carbonic acid. There is, consequently, still left | fluenced by a solitary instance mentioned i pendi 
149 Ibs. to account for the ¢ ic ac ume p. 18 I. do not call bt the credibility of Mr. 
orming roots and the lower part of the haulm. Again, | W Macnab, though m important diffic h 
according to the opinion of author, the atmosphere | ri in mind on ing his account; but I must 
ways tains ammonia, which is readily absorbed by | observe, that Ficus australis is a A ain whose roots grow 
humus, and forms that sal ch is most soluble and | in the air, and that i¢ appears to me more than probable 
contains the greatest proportions of qe! or the | that such plants are, more than others, possessed of qualities 
mation of humate 0 en am ve enable them to condense the moisture of the atmo- 
quantity of water is required, that quantity 1700 000 lbs.) | s even if this fact is admitted in all its fore 
brings to the plants 70,000 lbs. of humate of amenudhe, it tte nothing more, than-that Ficus australis constitutes 
This quantity contains, aieaets ing to a, calculation of | an excep to the general rule. Experiments b i 
Mulder, 42,000 lbs. of ca rhonia sgl “ if we suppose | this question is settled may be made every day. It will 
that only,one-tenth of the r in the nourish- | be fou ta plant in a pot dies if it is not watered, that 
ment of the plants, they receive stil 1 ht ibs. of hue in the open ground it continues to live for a iderabl 
acid. I could wish to lear m Dr. Liebig what length of time without rain, because the soi continually ~ 
am are to do with this bia surplus of lacbosts ab t atery vapours of the atmosphere, especially 
uring the night; but that when drought —> for a 
e other hand, the author at page 13, has made long period, plauts sryving the untry suffer, 
wie 
ee which render it in the highest degree impro- 
able that plants are nourished by humus contained in soil, 
Ate Fg repeated the old observation, that in forests 
warn i i nnually 
thei he a continually increases the proportion of 
peti without the assistance of manure, he produces a 
; f 
al. spa 
whether used for the growth of Forest-trees, Grass, Corn, 
or Turnips, “ve ee early the same quantity o 
carbonic acid. If this was true, it would prove that the 
aut a 
cannot be the source from et ch carbonic acid is iethon 
it must be the atmosphere. I think he has come to this 
ily. enture to a 8 
tain that the vegetable matter contained in soil is change 
id by t xygen of the ai 
h I oppose to those of Dr. 
in proportion ‘to the quantity of vegetable matter produced 
by the falling of leaves, the breaking ns branches, &c. 
Dr. Liebig next inse Ae ee eghs a absurd o 
vation : “ Humus,” he sa ing t 
the opinion of all scientifie men, ihe porecninnts and de- 
eay. Therefore there cannot be an original humus, as there 
before ho id wer; “carboni 
ar 
a and 
acid, oxygen, and hydrogen. Does Dr. Liebig think it 
more difficult for nature to bring about the combination 
hk hg last “mentioned substances, than that of the 
two 
After De. Liebig (p. 17, &e.) has repeated the 
known facts respecting the continued production oh ar 
bonic acid, and that nevertheless the portion of this matter 
contained in the atmosphere eas ae *not not increase, 
he brie ely as, a es of the carbonic acid?’ 
and he answ Cee wit it S absorbed by the wore “4 
plants from the air, voting“ 
after the carbon has been fixed in the plant, t the orygen is 
emitted.” This sibati however, 
so hasty a way, if it were only because the answer ex 
ion, What beco he 
It remains fixed in the plants, have nothing to do with the 
other questions, By what organ is uic acid intro- 
d ii plan ; 
been acknowledged since the times of Senebier, Priestley, 
and Saussure. But that itis certain, as Dr. Liebig thinks, 
open 
especially because the drought ayy Tee the capacity of 
the humus for absorbing Bak ot ure (Mitscherlich). These 
facts are known to every peasant, to every-gardener, but 
"i i Aye. are unknown to Dr, Lie ig. : 
e the absorption of ee c acid by leaves, the 
Phi spelt to the well-kno B axperimen nts of Saussure 
According to the sam Spat: he is obliged to admit 
that they emit carbonic vei at might 3 but yne 2 asserts, 
without earbon 1 is derived 
sates a quite capa sorte, pa that ts quantity thus 
o that w 
€ 
not been reported by Dr. Licbig, I shall take the liberty 
to oppose these well conducted and exact experiments, 
to the phrases of Dr. Liebig, and 1 think I may assert 
that in this matter there is stil a great vacuum in our 
knowledge, to fill up which, this author does not seem 
better qualified ae Pharos ogists. 
“* Mr, A. Dumas, in his Statics of Organic Chemist 
Meyen being aware of these difficulties, was Site the 
first and only phy stols gist to deny that the a tmoaphore | is 
improved by the function ae leaves, and h 
| posed a theory, resting, in on a very wreak founda- 
tion. Now, Dr. Liebig a Miers ate 
of afl segetils dbo ph py botanis sts, the assimila- 
tion of the car' arkoneg © ac the air is called in doubt, and 
that Abies of den 4 hat the air is impro ved by 
plants. if rattled prot of of his ct dats kno ignorance or 
every, 
Ear 
rather gross falsification of 
body, and it is not worth my Py to. ans 
fally. 
Liebig, after having (Pp. 26) eC Pom 
of cahigle "etl known facts, which “have produced in his a 
mind the certain iene oi that the carbonic acid emitted 
eats by plants enters them 0 bab Soir in that state, and 
that the oxygen absorbed et not Soy a3 mg “com- 
bustion ‘of the carbon, he at last, (p. 30), produces a de- 
cisive proof which, in his baci Males Saw that the 
lants give a greater quantity of oxygem to the wir than 
i ro He rests” 
Sey oe 
nder ms “st in the least degree useful to science ? 
is 
tica ally, ‘ied t were, “by ice; that in ean a ae ab- 
#4 dose and exchange takes place betwecn the at 
carbonic acid is more a mueurbe d tig se then oxygen; 
that ‘frost separates from the water the g hich it has - 
absorbed ; ne such a separation apes Ye ‘aki place at 
points an =i and, consequently, at leaves and small 
branches ; tha at—but this s is = n to _— that he ban 
apes the solution of t oned: ‘problem 
very easy a task, must stor 
gantly employed for the purpose of s 
fellows, all those botanists who have 
yim diborane erent on in rab 
inly am not partial to Mr. Meyen, 
eudi ig that | > 
that our ometric experiments are much too seanty to ‘ ih is 
the atmosphere is not subject to any change ia 
components, 
