542 SECTIONAL TRANSACTIONS.—J. 
following work has been performed with a view to investigating one of the 
simplest cases in vision, the relation between the intensity of the stimulus 
and the sensory brightness. 
Experiments have been performed in which three white circular patches 
are simultaneously presented side by side on a black background. ‘These 
patches differ only in respect of their brightnesses. ‘The intensities of the 
two outside patches bear a known ratio to each other, while the intensity of 
the middle patch can be adjusted to appear equally spaced in brightness 
between the outer patches, that is, its brightness is neither nearer one nor 
the other. Using this method, it is shown that consistent observations can 
be obtained, and that observers substantially agree in their estimations 
although real differences appear between them, but that fundamental 
difficulties arise which prevent a scale of brightness being constructed by 
this method. 
The experimental evidence is against the measurability of the brightness 
of visual sensation. 
Friday, September 8. 
PRESIDENTIAL ADpREsS by Prof. F. AveLING on The status of Psychology 
as an empirical science (10.0). (See p. 171.) 
Dr. WILLIAM Brown.—The psychology of personal influence (11.0). 
The problem of personal influence arises in a challenging form in the use 
of methods of suggestion and hypnotism, and also in the phenomenon of 
so-called ‘ transference’ in psychoanalysis. It is important to decide, if 
possible, how far hypnotic effects may be explained in terms of transference, 
and again what are the probable bases of temperamental compatibility and 
incompatibility. Wider possibilities, of a spiritual and psychic nature, 
should not be left out of account, so far as science can deal with them. 
Prof. F. A. E. Crew.—An attempt to determine the factors operating in 
Professor McDougall’s Lamarckian experiment (12.0). 
AFTERNOON. 
(Section meeting in two divisions.) 
Division i. 
Dr. R. H. TuHovutess.—Some practical consequences of phenomenal 
regression (2.0). 
The purchaser of a telescope for terrestrial observation wants objects to 
‘look big’ and not merely to make a large retinal image. Apparent size is 
not simply a function of retinal size. Distant large objects look larger than 
near small ones when their retinal sizes are equal. The extent of this effect 
(of phenomenal regression) differs in different individuals and under different 
conditions of perception. Monocular observation through a blackened tube 
is found experimentally to diminish phenomenal regression and it thus acts 
as a mental factor reducing the apparent magnification of a telescope. This 
is one reason for the greater satisfaction obtained by vision through pee 
lars even when these are of lower power. 
Similarly a condition of lifelike representation on a screen is that the 
