30 
Bulletin 65. 
building were oiled and the room in which the plants were growing 
was shut up and became too warm; these two things together gave 
them a decided set back, and later a thrips,' Thrips striata , accord¬ 
ing to Prof. Gillette, attacked the plants and did them much dam¬ 
age. Some of the plants, however, seeded. They were harvested, 
though in bad condition and very uneven in the degree of their de¬ 
velopment. The root system was well developed, the sand being 
filled with the roots. The weight of the tops as harvested was 
198.5 grams; that of the roots as washed out was 40 grams. The 
tops and roots were incenerated together and yielded 5.795 per 
cent, of soluble and 9.803 per cent, of insoluble ash, a total of 15.598 
per cent. 
§ 62. Examination of the feldspar used showed the presence 
of 11.993 per cent, of potash, and 2.988 per cent, of soda. Phos¬ 
phoric and sulfuric acids were present in very small quantities, the 
former equalled 0.041 per cent, and the latter 0.003 per cent, of the 
feldspar. 
§ 63. The nitrogen in the oat hay, roots included, was 3.2543 
per cent. 
The ash gave the following analysis: 
TABLE VI.—ANALYSIS OF OAT ASH GROWN WITH FELDSPAR. 
Per Cent 
Carbon. 0.172 
Sand. 8.135 
Silicic Acid. 15.737 
Sulfuric Acid. 4.411 
Phosphoric Acid. 3.982 
Carbonic Acid. 15.356 
Chlorin. 2.732 
Potassic Oxid. 15.959 
Sodic Oxid. 4.622 
Calcic Oxid. 21.709 
Magnesic Oxid. 3.906 
Ferric Oxid. 0.696 
Aluminic Oxid. 0.314 
Manganic Oxid. 0.163 
Ignition. 2.611 
Sum.100.505 
Oxygen Equivalent to Chlorin. 0.615 
Total. 99 890 
RESULTS SHOWN BY EXPERIMENT WITH FELDSPAR. 
§ 64. This ash is very anomalous in its composition as well as 
in the quantity present in the plants. The plants were not evenly 
mature at the time of gathering and were in bad condition. The 
question we endeavored to investigate, however, is perfectly answered 
by the results, i. e., the oat plant can use the finely divided feldspar 
as a source from which to obtain potash; for in this experiment, 
made under very adverse conditions, we find that the oat plants 
