INDEX 
TO THE 
PHILOSOPHICAL TRANSACTIONS 
FOR THE YEAR 1818. 
A page 
Acid, lithic or uric, description of an acid principle prepared 
from it, - - - 420 
Amphibia , on the urinary organs and secretions of some of 
that class of animals, - - 303 
Arc on the Meridian , an abstract of the results deduced 
from the measurement of one, extending from latitude 
go g f 3 8 4 ^ t 0 latitude 18° 3' 9,3", 6, N. being an ampli- 
tude of Q° 53' 45 // , 2. 486 
Asia, a memoir on the geography of the north eastern 
part of it, and on the question whether Asia and America 
are contiguous, or are separated by the sea, - 9 
Astronomical observations and experiments , selected for the 
purpose of ascertaining the relative distances of clusters 
of stars, and of investigating how far the power of our 
telescopes may be expected to reach into space, when 
directed to ambiguous celestial objects, - 429 
Atmosphere , of the correction for the buoyancy of it, 62 
Axes, on the character, number, and position of those by 
which the tints are produced, - - 229 
B 
Blood, on the changes it undergoes in the act of coagula- 
tion, - - - - 172 
- - some additions to the foregoing paper on this subject, 185 
