Tobacco as a Farm Crop for England. 
243 
It is here worthy of note that the dried residual or washed leaves burnt 
free from carbon much more readily than the original leaf. The above 
results were calculated into the percentage on original leaf by allowing for 
soluble extract, and the amount of ash, as also of nitrogen, extracted by 
water, was obtained by difference. 
Percentage op Ash, Extracted by, and Insoluble in Water. 
Ash. 
No. 1. 
No. 2. 
No. 
3. 
No. 
4. 
No. 5. 
No 
6. 
No. 7. 
Extracted (by diflf.) 
20-71 
18-16 
16- 
11 
18- 
65 
9-27 
10 
09 
10-72 
Not extrac ted 
4-57 
4-71 
5- 
08 
4- 
98 
7-22 
11 
32 
8-91 
25-28 
22-87 
21- 
19 
23- 
63 
16-49 
21 
41 
19-63 
These results are very important ones and leave very little doubt as to the 
artificial nature of the plant. The leaves are immature. The amount of 
mineral constituents, not extracted by water and which are consequently 
those forming part of the leaf itself, is exceedingly low in all the English 
samples, while the amount extracted by water is very high, thus showing 
the superficial nature of the mineral constituents. The high figures above in 
the four English samples showing the soluble mineral constituents no doubt 
account to a large extent for the high percentage of soluble extract of the 
original leaf. 
The amount of soluble and insoluble nitrogen is given in the following 
table : — 
Percentage of Nitrogen, extracted by, and Insolttble in Water. 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
No. 5. 
No. 6- 
No. 7. 
Extracted (by diff.) 
Not extracted 
2-89 
1-73 
2-90 
1-26 
2-82 
1-85 
3-24 
1-41 
2-45 
1-88 
1-59 
1-93 
1- 50 
2- 74 
4-62 
4-lG 
4-67 
4 -Go 
4-33 
3-52 
4-24 
It will be seen that a similar result in a less marked degree is obtained 
here as in the case of the mineral constituents: — ^a higher ratio of soluble 
nitrogen to insoluble in the case of the English samples than in the case of 
the foreign. The insoluble nitrogen may be taken to roughly represent 
the albuminoid nitrogen, as the determination of the albuminoid nitrogen in 
three of the above samples proved it to be so. 
An experiment was next conducted with a view to ascertaining the amount 
of internal combustion that took place when tlie leaves were treated without 
contact with air. Unfortunately these experiments did not prove so simple 
as was anticipated. Weighed quantities of each sample were placed in small 
combustion tubes, closed at oue end and drawn out at the other, and 
connected with a Sprengel pump. When a vacuum was obtained, the tubes 
were heated to very dull redness, about the same temperature being employed 
in each case. The gases which were produced were collected and measured. 
K 2 
