CHEMISTRY AND PHYSICS. 41 
Fourth Experiment.—The rabbit used in the second experiment was again 
confined in the apparatus for twenty hours, then immediately killed and dis- 
sected. No change could be detected in the organs. The blood seemed to clot 
more rapidly than normally, and the arterial blood was of a brighter hue. The 
venous blood was also probably a very little changed in color. 
Fifth Experiment.—Two bantam hens were placed in the apparatus under 
the same conditions as in the third experiment. They were kept there for six 
days and twenty-one hours. We had planned to continue the experiment a full 
week, but the oxygen supply became exhausted. We could not see that they 
were affected in the least at any time. 
From these experiments, we feel justified in concluding that an atmosphere of 
oxygen produces no permanent excitation, and no unnatural sleep or uncon- 
sciousness, and is not destructive to animal life. 
EFFECT UPON THE COMPOSITION OF THE SOIL OF CONTINUOUS 
CROPPING BY WHEAT. 
BY J. T. WILLARD, EXPERIMENT STATION, MANHATTAN. 
Read before the Academy December 28, 1900, 
In the fall of 1880, Prof. E. M. Shelton, of the Kansas State Agricultural Col- 
lege, laid out an acre of land to be devoted to the continuous production of 
winter wheat, without fertilization or renovating treatment of any kind. This 
experiment was doubtless suggested by the famous plat at Rothamsted, Eng- 
land, which Lawes and Gilbert have kept under such conditions since 1844. Un- 
fortunately the plat selected by Professor Shelton was situated so that the 
growth of the institution has seemed to compel the abandonment of the experi- 
ment. The plat also, having a rather pronounced slope, was not as well adapted 
to the purpose of the experiment as would be desirable. 
The abandonment of the experiment having been determined upon, it seemed 
of interest to make analyses of the soil of the plat, and, for comparison, of that 
of the adjoining field, which has borne a variety of crops, though not in any 
regular rotation. For sampling these fields four spots were selected in each, and 
pits sunk to the depth of the proposed sampling. A prism of soil six inches 
square was then cut from the side of each and divided into four parts, represent- 
ing, respectively, the first nine inches from the top, and three intervals below 
this of twelve inches each. Four samples were thus obtained from each field for 
each depth. These four samples were then intimately mixed to form a composite 
sample, which was carefully air dried and subsampled for analysis. 
The analyses were limited to determinations of the moisture, insoluble residue, 
potash, lime, nitrogen, and phosphoric acid. The accompanying table exhibits 
the results as calculated to a water-free basis: 
TABL¥ showing (1) composition of soil at several depths, from field cropped in wheat con- 
tinuously for eighteen years; and (II) that from an adjacent field that had borne a variety 
of crops during the same period. Results calculated to a water-free basis, and in percent- 
ages. 
0 to 9 ins. 9 to 21 ins. 21 to 33 ins. 33 to 45 ins. 
I II I II. I II I II 
OUaGH i cocite sis ciaicia siete’ ccico'ecleeitieinis 0.720 | 0.656] 0.584 | 0.716 | 0.653 | 0.631 | 0.615 0.694 
PANO eu eiscabclvetevcsweaceccc cv 0.750 | 0.686 | 0.740 | 0.722 | 0.783} 0.611 | 0.811 0.826 
UEORE Hiei: oie calpiia veiel ns eiesiels 0.216 | 0.245 | 0.169 | 0.152} 0.104] 0.117} 0.087 0.081 
Phosphoric acid...........0+.00: 0.107 | 0.140} 0.044 | 0.092 | 0.017} 0.053 | 0.028 0.C61 
Insoluble residue...............- 83.948 | 83.107 | 81.524 | 80.723 | 84.335 | 83.004 | 85.281 | 84.216 
