Gruis, taken from six plates of the same dispersion, and comparable quality, density, and definition. Successive columns give the wave-length, the arithmetic mean intensity, and the standard deviation

.

[TABLEXVIII]

Line Int. Line Int. Line Int. Line Int.
42158.41.043194.80.843767.80.644514.51.5
422716.01.443214.00.043794.20.344555.01.0
42476.00.0432610.40.5438310.30.844626.00.8
42507.00.043304.60.843956.30.444827.70.7
42549.01.043323.60.543982.70.844907.30.4
42609.02.143334.00.044026.30.444957.50.4
42728.70.843378.70.844059.00.545026.00.0
42759.51.343409.51.144099.00.545545.30.4
42834.30.443529.21.144157.70.845645.80.7
429010.61.043606.81.044359.20.945726.01.0
43158.30.743706.80.644448.91.2

These measures are strictly representative of the material as a whole, for the plates of

Gruis were measured at wide intervals in the ordinary course of the work, and were selected for illustration because there was a greater number of suitable plates of this star than for any other.

HOMOGENEITY OF MATERIAL

The observational material on line-intensities follows in tabular form. The measures were made in two groups, comprising respectively the hotter stars and the stars cooler than Class