360 
REPORT — 1854 . 
experiment. The abseucc of the chemical rays favours the first growth of 
rootlets, and the presence of the luminous rays does not impede it. After¬ 
wards the opposite effect takes place ; the roots are stopped in their develop¬ 
ment by the yellow ray much more than by all the rays of the spectrum in 
combination. The red or calorific ray is on the whole the most lavourahlr 
to the growth of the roots, even more so than the complete absence of all 
solar radiations. The shooting forth of the plume is also favoured by the 
withdrawal of the chemical rays, esjieciallv just at first; but the full sod 
healthy development of leaves requires all the rays of the spectrum, the 
luminous being particularly necessary. Several other peculiarities may be 
noted; for instance, the downward tendency' of the roots under the purr, 
luminous influence; the comparatively greater development and strength of 
the membranous sheath under the calorific agency ; and the late but abundant 
growth of side-rootlets, where nil the solar radiations were admitted. 
The results of the experiments on wheat recorded in the previous Report, 
where there was the presence of soil and change of air, appear to'indirate 
still more clearly the beneficial character of the luminous emanations, for 
the plants under the yellow shade were found even to excel those which bad 
grown in white light, while, as in the experiment just detailed, the cuUmgo 
of the luminous ray by the deep blue glass militated greatly against 
health of the plants. The protection of the rootlets from the yellow ruy 
may be fairly considered an advantage, but a proper series of expennin" 
on wheat-aeedH surrounded by earth is still a desideratum. . 
We have now to consider the growth of the peas under the different &ji 
influences. It has been already stated that twelve peas soaked Wwater 
placed on the bricks along with the wheat seeds, on April 21st- 
21th they were found to be swollen and beginning to burst. The sec 
the yellow, obscured yellow, ami obscured colourless glasses, were the 
rapid in their first development. On the 29th, the plumes began to ni l 
under the obscured colourless, yellow, and red shades, and two ). f 
wards under the blue and colourless. The plants under the V b **"V* tl* 
glass appeared very unhealthy. The radicles grew astonishing, [ (i> 
yellmv glass, and became very long under the red aud °ta= cur T , ‘ 
On May 8th, the plants in complete or partial obscurity were found to 
]"ch es high; under the red, 2 inches; under the yellow, not quite so m 
whde even on the ] 1th, the plants under the blue had only ^ 
themselves, and under the colourless class only one seed bad put to 
and that was but half an inch in length. J , „ a ffere ^ 
n the 12th they were more fully examined, and drawing |. 
Under the colourless glass, the peas resembled fig. 1, Plate 
tie first stage ol development, the principal root short an ^ 0 ^. 
short and thick secondary rootlets, all fringed with hairs. t" d poder^ 
• »e peas were in a somewhat more advanced stage, like _ sli )i 
£ d ’.. ten P ,ant8 t had grown somewhat like fig. 9 ,—roots strafe S Tbt 
ending towards the light, with many leaflets of a deep green <*> « 
shown ■ ,lie ? d,ow fr* were characterized by enormou® d 
Ninp f 11 , l S* 4, which turned away from the light in a VC, T presents 
N;ne of those under the obscured coldurless had the appearanc P ^ 
lLl?;fC f ,,grootai lon S succulent weak stalks, and 
bit w tl l° b n CUrCfl yell#nv ’ plants appeared for the most £ “ 
had ! " ' r ° 0ts ‘ ,l,c, ug|i two of them, which were nearest 
fe noTr T ‘ a ,ikc tha * represented in fig. 5. 
theptas had grown like fig. c,—roots irregular, having few s d tf)D 
stalks succulent, but tolerably erect, bearimr vellow leaflets. W 
