tinval gentle circulation. While the observations were taken, 
(1808—1811,) the building was not heated, and the lights used 
were a few scattered tapers. It appears, that from nearly the end 
of March to nearly the end of August, the air within the Minster 
was colder than the mean temperature of the air without; and - 
from nearly the end of August to nearly the end of March, 
it was warmer. Dr. Robinson remarked, that by a slight modi- 
fication, these observations might be made subservient to the 
purpose of determining the rate at which the several strata of air 
as you ascend, alter their temperatures as the conditions upon 
which their equilibrium depend, is varied; which determination 
would have an important ee on the sabject of atmospheric 
refractions. 
- Prof. Lloyd communicated a paper containing the Resuits of 
some acne antes on the phenomena of thin plates in Polarized 
ht. 
Profs Wartmann, of Lausanne, read a paper on what he calls, 
Dalionism. One of the most extraordinary affections to which 
the eye is subject, is an incomplete vision of colors, which has’ 
been called Daitonism, after the celebrated Professor, who was 
the first to describe it in an exact manner. He then laid before 
the meeting, an extract from a more extended work, containing 
in substance, the following observations. The Daltonians form 
two classes ;—that of the dichromatics, who discern only two 
colors, generally black and white, and who appear endowed with 
a remarkable faculty of vision in a state of darkness: and that of 
polychromatics, who have the definite perception of at least 
three colors. Daltonism is not always hereditary; it does not, 
even, always date from birth. Decided colors appear black to 
many Daltonians, if they be not illuminated by a very brilliant 
light. ‘The number of colors of which the polychromatic Dal- 
tonians are sensitive, is not constant; some only see three, others 
four, among which blue and red may be expressly mentioned. 
The extremes of red and violet are often not distinct; a fact 
which the Professor thought to have a connection with the ques- 
tion uf the number of elementary colors. The degree of polish 
of the Colored surface has an influence on the appreciation of. 
colors. Some Daltonians have an equal cognizarice of the bright- 
ness and the discoloration of supplementary — _ we do 
not recognize as such. 'T'wo colors appear to us ended by @ 
