CHEMISTRY: BURDICK AND ELLIS 
645 
ing to other than the isometric system is hkely to throw most light on 
the fundamental factors involved, such as the interatomic forces and 
the size and shape of the atoms themselves. 
This research was carried out at the suggestion of Prof. A. A. Noyes 
with the aid of a grant made to him by the Carnegie Institution of 
Washington, for which we wish to express our indebtedness. 
Description of the Apparatus and Procedure. — The method employed 
was in principle the same as that described by W. H. and W. L. Bragg,' 
but the apparatus was modified in several respects. 
The electrical equipment for the X-ray excitation consisted of an 
interrupterless transformer of 20-kilowatts capacity. The X-ray tube 
was provided with a target of specially purified palladium, 2 mm. 
thick, silver-soldered onto a copper block, the face of which was set 
nearly perpendicular to the direction of the cathode rays. The elec- 
troscope used was one of the double- til ted form devised by Bumstead. 
The crystal used in this investigation was selected from a number 
kindly loaned us by Prof. C. H. Warren of the Massachusetts Institute 
of Technology. The crystal was of the sphenoidal type,^ approxi- 
mately 8 mm. on the edges. 
Summary of the Observations. — The following table summarizes the 
observations. The significance of the 'calculated' angles and inten- 
sities will be described below. 
TABLE I 
Summary of the Observed and Calculated Results 
CRYSTAL PLANE 
ORDER OF RE- 
FLECTION 
ANGLE OF REFLECTION 
ELECTROSCOPE 
DEFLECTION 
RATIO OF INTENSITIES 
Obseirved 
Calculated 
Observed 
Calculated 
(100) 
I 
6°25' 
6°25' 
5.5 
100.0 
100 
II 
12°55' 
12°55' 
9.0 
164.0 
217 
(001) 
I 
6°32' 
6°32' 
13.0 
100.0 
100 
II 
13° 9' 
13° 8' 
33.5 
256.0 
222 
(111) 
I 
5°32' 
5°35' 
49.0 
100.0 
100 
II 
11° r 
11°14' 
6.5 
13.0 
4 
III 
16°33' 
16°58' 
4.0 
8.0 
7 
(111) 
I 
5°41' 
5°35' 
69.0 
100.0 
100 
II 
11°26' 
11°14' 
10.0 
14.0 
4 
(110) 
I 
9° r 
9° 6' 
190.0 
100.0 
100 
II 
18°28' 
18°27' 
45.0 
24.0 
20 
III 
27°52' 
28°19' 
11.0 
6.0 
7 
(110) 
I 
9° 4' 
9° 6' 
61.0 
100.0 
100 ■ 
II 
18°23' 
18°27' 
29.0 
47.0 
20 
(101) 
I 
9°10' 
200.0 
100.0 
100 
II 
18°29' 
18°35' 
50.0 
25.0 
20 
III 
28°25' 
28°32' 
9.0 
4.5 
7 
