~~ 2 > 
— ee 
Popcocilingys 6fthe' British Assilations 343 
* #*£ & 
Sir D. Brewster read a paper on the cause of the increase of 
color in objects seen with the head inverted. It has been long 
known to all artists and tourists, that the eolors of external ob- 
jects, and particularly of natural scenery, are greatly augmented 
by viewing them with the head bent down and looking back- 
wards between the feet, that is, by the inversion of the head. 
The colors of the western sky, and the blue and purple tints of 
distant mountain scenery are thus beautifully developed. ‘This 
position of the head is a very inconvenient one; but the effect 
may be produced nearly to the same extent by inverting the 
head so far as to look at the landscape backwards beneath the 
thighs or left-arm. It is not*easy to describe this change 
of color, but it may be stated that the colors of distant moun- 
tains, which appear tame and of a French gray color when 
viewed with the head erect, appear of a brilliant blue or purple 
tint with the head inverted. * * While in perplexity about the 
cause of the phenomenon in question, I had an opportunity of ob- 
serving the great increase of light which took place in an eye in 
astate of inflammation. This increase was such, that objects 
seen by the sound eye appeared as if illuminated by twilight, 
While those seen by the inflamed eye, seemed as if they were 
illuminated by the direct rays of the sun. All colored objects 
had the intensity of their colors proportionally augmented ; and I 
was thus led to believe that the increase of color produced by the 
partial or total inversion of the head, arose from the increased 
quantity of blood thrown into the vessels or the eye-ball,—the in- 
creased pressure thus produced upon the retina, and from the in- 
creased sensibility thus given to the sentient membrane. Subse- 
quent observations have confirmed this opinion, and though I can- 
Hot pretend to have demonstrated it, I have no hesitation in ex- 
Pressing it as my conviction that the apparent increase of tint to 
which I have referred, is not an optical, but a physiological phe- 
homenon. If this is the case, we are furnished with a principle 
Which may enable us not only to appreciate faint tints, which can- 
hot otherwise be recognized, but to perceive small objects which, 
With our best telescopes, might be otherwise invisible. 
Mr. Snow Harris’s report on the working of Whewell’s ane- 
mometer at Plymouth, was read by the secretary. The instru- 
ment being now effectively at work, Mr. H. proposes to have 
°ompleted by the next meeting a graphical delineation of the in- 
