John William Hart . 
45 
in their experiment with the Neguudo leaf that 4'2% of the total 
incident energy is absorbed by the chlorophyll. These incidental 
numbers have been given some importance by Weigert, who 
4-1 
assumes from them that — or 98% is the efficiency of the assimil- 
atory system. This result is indeed, as Weigert himself admits, 
surprising, and he regards the plant as the most ideal photochemical 
machine which could possibly exist. Presumably Weigert would 
have been still more surprised if he had chosen a value from 
another of Brown and Escombe’s experiments in which 4-48% of 
the total energy received by the leaf was used in assimilation. This 
4.48 
by his method would have given an efficiency of — or 107%. 
• jLi 
But without this absurdity it is clear that numbers obtained 
from such data are completely valueless. 
(To be concluded). 
JOHN WILLIAM HART. 
O N September 15th, 1916, we lost an ardent student of 
Nature in the person of John W. Hart, B.Sc., Corporal 
in the 15th Batt. London Regt. Wounded in the attack on High 
Wood during the first wave of advance on the Somme, he crawled 
to the succour of a comrade, but both perished in the heat of battle. 
It had been his desire to go through the war as a private, but 
influenced by other considerations, he was, at the time of his death, 
about to accept a commission. 
John Hart was a “ son of the soil ” in the truest sense, that of 
filial affection, which appears even in letters written almost under 
fire, in which he speaks of “ such a longing to be amongst the 
flowers and springing plants—to dabble with seeds and soils.” 1 
Nature for him included the “ stones ” also, and he soon became 
known at the front for his pursuit of fossils, a task that must have 
cost him many an ache, as one realises in handling—in the light of 
his own list of compulsory impedimenta—a particular fine speci¬ 
men of Sigillaria, brought home by him in the spring. His 
enthusiasm spread to his comrades, and he says: “It is really 
amusing how whenever we are on a fatigue having anything 
to do with the slag refuse from the mines, I get inundated with 
