372 INFLUENCE OF LIGHT AND RADIANT HEAT ON TRANSPIRATION. 
Flowers of Lilium crocewm (156 square centimetres of surface, 
sepia, Vaated with faint band in blue and strongly marked absorp- 
n in indigo and violet) gave— 
Milligrammes per hour. 
In obscurity . : . : : 60 
In diffused light : : ‘ ‘ 93 
In full sunlight : : ‘ : 178 
White flower of Malva arborea (150 square centimetres of surface, 
weak colouring-matter with spectrum of Lilium croceum, but only for 
the space of 2 centimetres) showed— 
Milligrammes per hour. 
In obscuri : ‘ ' : ‘ 35 
In diffused light ; ; , ‘ 42 
In full sunlight g ‘ 95 
The comparative list stands thus— 
Amount of water-vapour in milligrammes Aenean per hour for 
every 100 square centimet 
cana Diffused Sunlight. 
light. 
Spartium junceum ; ‘ 64 69 174° 
Lilium croceum . 38 59 114 
alva arborea 23 28 70 
Bticlated Maive cekiis debiliace wikdiiclta Onl 
Gre P ‘ 
pret of the ultra-red rays on transpiration.—Déherain, by ex- 
posing a plant in saturated air behind a solution of iodine in sulphide 
of carbon, which allows only these rays to pass through, came to the 
conclusion that they have no effect on trans ne a The present 
author has, however, arrived at a precisely opposite result. - 
Relation between refragibility of light and transpiration —An ex- 
periment made with thr nm Maize plan saturated 
medium, aie the following for the effect of the “diffeient ieee on 
transpiration 
Milligrammes per hour. 
i 5 ‘ mM P 136 
Orange. : 122 
Blue é 146 
Ultra-violet ‘ i 70 
bseurity . 62 
And this was ridden ss beens 2 other experiments, both in n satu 
rated and in unsaturate 
ans luminous ones, ave preintaal fost in transpiration ; and that the 
a soluti hlorophyll have only a feeble 
discovered a new function of 
