OX THE INFLUENCE OF SOLAR RADIATION ON PLANTS. 385 
necessary in the germination of seeds. The explanation given is that that 
dement is required for instituting the action that converts the fecula of the 
cotyledon into sugar. It is unquestionable, that in the majority of cases, 
plants after the first stage of their growth require a certain supply of car¬ 
bonic acid, by the decomposition of which they obtain carbon, setting free 
oxygen. My brother and I have shown that plants will exist well for a con¬ 
siderable time in an atmosphere devoid of oxygen, for instance in nitrogen, 
hydrogen, coal-gas, or carbonic oxide. In order to see the effects of all 
these atmospheric conditions on the germination of wheat and peas, the 
following experiments were made during the latter part of May and the be¬ 
ginning of June. 
Six wheat-seeds and six peas were placed on folds of linen floating on 
mercury, and covered with a colourless glass jar having a capacity of about 
20 cubic inches. The linen preserved the seeds from the mercury, and 
jras kept wet by the introduction of a small quantity of water. The jar was 
full of atmospheric air, and was placed on the table before the window having 
8 S.F.. aspect. After a couple of days or so the peas germinated, and shortly 
“towards the wheat. They grew for about a week, and retained a healthy 
■ppearance much longer. The experiment was twice performed with similar 
results, and showed that the arrangement was applicable to the proposed 
wpenments. 
A precisely similar arrangement was made in a jar containing 29 cubic 
‘“p es of hydrogen gas, and having in it a tube containing pyrogallate of 
J® h0 113 absorb any trace of oxygen which might be accidentally 
[I eri i* In the g as > or might be evolved from the seeds themselves. In four 
ba( S | S " 0 '* en P feas had begun to burst. 'They put forth short radicles, 
„1 n .° Ph"ue, and in about a week afterwards they were all decaying. The 
;' H 910 „ Wed no appearance whatever of germination. This experiment was 
lW T Mnmed with the same result. 
N 0 t r r h arran ®^neut was made in a jar filled with carbonic acid. 
TJisvdUr 4 ? a PP e . arance was indicated by'either the wheat or the peas, 
m, e ' e( '» becoming soft and swollen, and emitted a most offensive smell 
^removal of the jar. 
ti on of p! me 4 - WMdone 1,1 a J ar filled with common air, anti containing a solu- 
which i./'iY? P° tas h * n entail capsule, so ns to remove any carbonic acid 
lul the np 1 u glVRn off b y 11^ seeds. In about three days both the wheat 
Kr„w for ai» ? . be 8 ua to burst 5 four out of the six of each continued to 
the cnrhn.,in ° U -j a,,t l remained healthy afterwards. The removal ot 
Uut j„ . c aci(l > then, did not affect the germination. I subsequently found 
hiquirv inhfP | cnmen t' 1 had almost, exactly repeated one of Mr. Elliss in his 
of seed/’ y.,.° n cban S es produced on atmospheric air by the germination 
the iar hnii i e en, Pl°yod peas, and satisfied himself that all tho oxygen 
The effort a h sor hed by the germinating plants. 
®»wjcc of h,„. 0,1 the germination of wheat and peas under the in- 
S^es, havim, lfleient scdar radiations was also tried. The small coloured 
f*P*rtinem*wL iCa I lacit y « f 172 to 177 cubic inches, were employed, and the 
' a already ,1 ™ .^‘'dueled like those under the coloured shades which have 
?" the 8th hnfi a *i Cd * S( -f*ds were placed on the bricks on May 2 nd. 
b,,t they s’,, 1 tlie wheat and the peas had burst under the colourless glass, 
dead ~. ecame mouldy, and before the end of the mouth they were 
“°t those umliYfi. 86 ^ 8 untJer the yellow glass ran much the same course; 
and b l l! cb,ue glass, though they did not burst till the 11th, gf* 
J ,n ches. ‘ Th 26th ‘wo of the wheat plants had attained a height ot 4- or 
1854. fte ex periment was discontinued on June 5th. The plants 
