79 
6. Chlorides as indicating animal sources. 
7. Oxygen as indicating activity of decomposition or 
destruction. 
8. Total organic matter and ammonia, by weighing and 
other methods. 
PHYSICAL AND MATHEMATICAL SECTION. 
December 31st, 1867. 
Joseph Baxendell, F.R.A.S., Vice-President of the 
Section, in the Chair. 
“Solar Radiation Observations, made at Eccles, near 
Manchester,” by Thomas Mackereth, F.R.A.S., F.M.S. 
Feeling considerable interest in the paper read by Mr. 
Baxendell, F.R.A.S., at a recent meeting of the Physical 
Section, and at a general meeting of the Society, on this 
subject, I have reduced five years observations which I 
had made at Eccles with an ordinary black-bulb ther- 
mometer placed on the south side of the shade stand, four 
feet above the ground. The thermometer had been duly 
compared at the Kew Observatory. I was chiefly induced 
to make these reductions because the discussions of Mr. 
Baxendell on the subject were from observations made at 
Oxford by means of a thermometer placed somewhat simi- 
larly to mine, at least as mine was placed during the five 
years I have reduced. 
