128 Proceedings of Royal Society of Edinburgh. [mar. 7, 
lines D and E; therefore conclude that the most energetic rays of 
white light for root-absorption coincide with those for assimilation. 
In the presence of light, or the different rays of white light, the 
two processes go on side by side. 
Albuminoid Formation. 
The mode of formation of albuminoids in the vegetable kingdom 
is said to be unknown. We know, according to Lieberkiihn, that 
the albumens have an empirical formula of C7 2 H 112 N 18 S0 22 . As this 
molecule contains sulphur , the increase of protoplasmic (albuminoids) 
matter in the living plants, as far as the sulphur is concerned, would 
only have come from the sulphur of the ferrous sulphate, as there were 
no other sulphates present in the soil. Moreover, we find the largest 
percentage of albuminoids in the plants when they have been grown 
in the yellow part of white light, as the following table shows : — 
Percentage of Albuminoids. 
Mustard 
Plants. 
Bean 
Plants. 
Pot No. 1 exposed to red part of spectrum, gave . 
„ 2 „ orange 
,, 3 ,, yellow ,, 
,, 4 ,, green 
j, 5 ,, blue ,, • 
,, 6 „ indigo 
,, 7 „ violet 
23-3% 
25- 5 
27*6 
26- 2 
21*1 
18-4 
13-0 
2- 4% 
4 '2 
6*5 
5-3 
3- 6 
2-2 
1*8 
Also, the percentage of sulphur (estimated directly) was the largest 
in each case when grown in the yellow part of the spectrum. 
Dr W. J. Kussell, F.E.S. (of St Bartholomew’s Hospital, London), 
found that in those plants grown by the aid of iron sulphate the rela- 
tive amount of chlorophyll (in equal areas, and also in equal weights 
of the leaves) is increased over those not grown with the iron manure. 
The following table gives — 
Dr Russell’s Estimation of Relative Amount of Chlorophyll in 
the Leaves of Dr Griffiths’ Crops of 1884. 
Chlorophyll in 
equal areas of 
the leaves. 
Chlorophyll 
in equal weights 
of the leaves. 
f (1) Beans grown with iron sulphate, 
100 
100 
\ (2) ,, without ,, 
79 
76 
f (1) Turnips grown with ,, 
59 
61 
\ (2) ,, without ,, 
40 
39 
