142 A. Pedler —Bleaching action of light on colouring matters . [No. 2, 
sets of experiments were tried in which coloured substances were 
exposed to the action of sunlight after being moistened with water, 
and the bleaching under these circumstances compared with that 
produced by sunlight when the coloured bodies were kept free from 
water and only exposed to moist air. In all cases the presence of 
evaporating water rendered the bleaching much more rapid. 
It will be seen that in the above list, A to G inclusive, no less than 
97 experiments were started, and in addition to these a good many 
others were made, which are not reproduced in detail. Bach experi¬ 
ment was examined every few days at first, and later on every few 
weeks, and the condition of the specimens was compared with freshly 
prepared specimens when necessary, and the results carefully recorded. 
Hence a large mass of facts was obtained. It will be seen that it 
would be impossible to describe the detailed results of each individual 
experiment, as this would take a large amount of space, nor indeed are 
the results of sufficient value to make the publication of the details 
necessary. Hence the main results only of the experiments are sum¬ 
marised in seven tables, A to Gr, which are printed below. 
It may be convenient here to explain that the comparative results 
shown in tables A and B, are intended to differentiate between the 
causes referred to in 4 previously. The comparison of the results in 
B and C, is intended to differentiate between the causes referred to in 
1 and 2. The comparison of the results given in D and E, and given in 
E and Gr, is again intended to differentiate between the causes referred 
to in 1 and 2, and finally the results of D and E together, compared 
with those of F and G together, will enable a conclusion to be obtained 
with reference to cause 3. 
