100 
Dr Gilby on the Respiration of Plants. 
Tan MS 36“ 6& ... 9.87606 
Tan MN 7 07 ... 9.09640 
Log Mm 1925'' ... 3.28443 
12.^083 
Log M « = 60)32.0'' 2.50477 
5'.20" 
Tan ZS = 46“ 46' ... 10,02680 
Tan NS - 31 45 ... 9.79156 
Log S s = 60" ... 1.77815 
ii.^on 
Log s 0 = 35" ”1.^291 
Apparent distance, - 38° 52' 00" 
Mn, - - —5 20 
so, - - -{- 00 35 
Correction for 2d difference, 4-00 11 
True Distance required, 38 47 26 
Liverpool, Nov. 4 . 18 ^ 0 . 
Art. XIII . — On the Respiration of Plants. By W. H. Gilby, 
M. D., M. G. S. In a Letter to Professor Jameson. 
Having been much interested in that inquiry which my friend 
Mr Ellis has so ably and ingeniously conducted in his Treatise 
upon the chemical changes produced in the Atmosphere by the 
Respiration of Plants, and having myself executed many experi- 
ments upon the subject at the time of my graduation, I thought a 
short account of the nature of those experiments, and of the con- 
clusions to which they gave rise, might not be unworthy your no- 
tice. I am the more anxious to give such a statement, because it 
frequently happens, that the pages of our journals are still filled 
with many frivolous observations, sometimes gravely announcing 
as a new discovery, that plants do really vitiate the air, and at 
other times repeating the old notions of Priestley, all tending to 
shew a complete oversight of Mr Ellis’s truly philosophical work. 
In a work even written in a very acute and sensible manner by 
the Reverend Mr Keith, upon the Physiology of Vegetables, the 
reader is left very much in the dark with regard to the ultimate 
question of the real respiratory function of plants. He embo- 
dies, as far as I recollect, the opinions of the most sensible wri- 
ters upon the matter, which are oftentimes in contradiction, but 
neglect to satisfy us, by drawing any reconciling conclusion. Se- 
veral writers, in particular Sennebier, Ingenhousz, and- Saussure, 
have, shewn that the changes produced on the air are quite dif-^ 
ferent, according as the plant is placed in the sunshine or in the 
