THE SOURCES OF THE NITROGEN OF VEGETATION, ETO. 489 
TasLe IIT.—Showing the amount and composition of the Gas given off into 
a Torricellian vacuum, by plants exposed to sunlight. 
Total | Per cent. 
| Gas col-' 
Date. How manured, &e. lected, : Oar || OnrEen 
cub. — Oxygen.| bonic |i oO a. 
cents. gen. acid, pe a 
Wheat (whole plant), 1858. 
UMS Pe, INMATE ¢ css anczckins axcidsteniar genie evincunwe st aaneeneeqees 44-4 || 73°65 | 21°17 | 5°18 |) 26°35 
June 23, (Unmanured ............cec cee seseeeceeeesscesecsseeeenssceeeeef] 84°83 | 77°01 | 21°26 | 1°73 |] 22°99 
Jone 30. |/Unmanured siisisicasscncenescsce nee caneeeass seo nnansbasrers cet 44:1 || 72-79 | 20°86 | 6°35 || 27-21 
June 22. {Mineral and Ammoniacal manure................0.s00004) 54°5 {| 73°76 | 21-29 | 4:95 | 26-24 
June 23, /Mineral and Ammoniacal manure...............e000e+004{/ 42°] | 78°15 | 15°44 | 6-41 | 21-85 
June 25./Mineral and Ammoniacal manure............ccecceeeceee 37-2 || 78°76 [19:09 | 2-15 || 21-24 
Grass (whole plants), 1857. 
August 15.|Mineral and Ammoniacal manure: second crop ...... 390 || 82°10 |16+19 | 1:71 | 17:90 
August 15. |Mineral and Ammoniacal manure: second crop...... 47°38 || 77:08 | 15°35 | 7-57 || 22-92 
August 15.|Mineral and Ammoniacal manure: second crop ...... 41°6 || 76°56 | 21-46 | 1:98 || 23-44 
August 17. |Mineral and Ammoniacal manure: second crop...... 39°9 || 75°07 | 23-39 | 1-54 | 24-93 
August 18. |Mineral and Ammoniacal manure: second crop...... 36:8 | 79°88 | 15°19 | 4:93 | 20-12 
August 18.|Mineral and Ammoniacal manure: second crop...... 42°3 || 80°23 |15°97 | 3°80 || 19-77 
Beans, 1858. 
July  12.|Mineral manure; almost podding .........,scsesseeceeeee|| 44°3 |] 71°11 | 18-28 | 10°61 || 28°89 
July 12. |Farm-yard manure; almost podding..........secsese0eee] 45°38 |] 73°14 | 10°26 | 16-60 || 26-86 
July  15./Unmanured ; almost podding ..........cccseceeeceeeeeee|] 25°9 |] 82°63 | 15°83 | 1°54 | 17°37 
July 15.|Mineral and Ammoniacal manure ; almost podding...!| 30-9 || 70°55 | 20°71 | 8°74 || 29°45 
The general accordance in the proportions of Nitrogen found throughout this Series, 
together with their general approximation to the amounts observed in Series 2 (Table IT.), 
and the consequent similarity in range of the sums of the two remaining gases—carbonic 
acid and oxygen—point to the character of the change which has taken place, by virtue 
of which the proportion of carbonic acid is diminished, and that of oxygen increased. 
The variations in the amounts are, nevertheless, somewhat considerable; and we feel 
that it would be requisite to exercise considerable caution in attempting to refer them 
to any other than accidental circumstances beyond our control. There can be no doubt, 
however, that the carbonic acid, shown to exist in the plants in the shade, has yielded 
the oxygen evolved when in the sunlight. But the mutual relations of the two gases will 
be more clearly brought to view by a consideration of the results yet to be adduced. 
Experiments, Series 4. 
These experiments, as well as those of the succeeding Series, were arranged to show 
the influence of the time of action of the sunlight on the plant, upon the relative pro- 
portions of carbonic acid and oxygen. 
In the Series of experiments now under consideration, duplicate quantities of the 
3x2 
