614 



SCIENCE 



[N. S. Vol. XXVII. No. 694 



lilies having several components except 

 under quadruplets of zircon designated by- 

 interval 3a/8. No series was found here. 

 An extended abstract of this investiga- 

 tion may be found in the Physical Review. 



On the Absorption of Short Electric Waves 



by Air at Different Pressures: James E. 



Ives and R. B. Clyde Gowdt. 



It has been known for some time that 

 wireless telegraph messages can be sent 

 farther at night than in the day. One 

 explanation is that sunlight ionizes the air 

 and this increases absorption. 



To investigate this in the laboratory 

 short electric waves were used, and were 

 sent through a glass chamber in which the 

 pressure could be varied. The waves were 

 excited by a Righi oscillator 5 em. long and 

 received upon a thermo- junction made of 

 fine iron and constantan wires. The inter- 

 vening chamber was 44.5 cm. long, with 

 plate-glass ends. Pressures were used 

 ranging from .5 mm. of mercury up to 1 

 atmosphere. Two maxima of absorption 

 and one minimum were found. One of the 

 maxima is near zero pressure, the other 

 between 40 and 60 cm. of mercury. The 

 minimum lies between 25 and 35 cm. of 

 mercury. The percentage absorption is not 

 large, varying between -|- 7 per cent, and 

 — 7 per cent, for the whole tube, or be- 

 tween -j- .15 per cent, and — .15 per cent, 

 for each centimeter of its length. 



The Magnetic Properties of Antimony: 

 AntHUE L. Foley, Indiana University. 

 Antimony can be made to exhibit either 

 paramagnetic or diamagnetie properties by 

 changing the temperature conditions under 

 which it solidifies and crystallizes. 



A Repetition of Wheatstone's Experiment 

 of 1834: Francis B. Nipher, Washing- 

 ton University, St. Louis. 

 The paper gave reproductions of "WTieat- 



stone's figures in Phil. Trans., 1834. It 



was pointed out that it seemed somewhat 

 improbable that his mirror could have been 

 given a velocity of 800 revolutions per 

 second. The three sparks in a line half a 

 mile in length were photographed. Y/hen 

 Wheatstone's connections were used his re- 

 sult was not obtained. When one end of 

 the line was grounded, the sparks always 

 began at the gap nearest to the terminal 

 of the machine and the others followed in 

 consecutive order in time. The result was 

 the same for the positive as for the nega- 

 tive discharge. With Wheatstone's con- 

 nection the middle spark should appear 

 last, but the result was so aiSected by dis- 

 tributed capacity that his result was not 

 attained. 



Determination of the Susceptibility of 

 Copper and Tin and their Alloys: 0. C. 

 Clippord, University of Chicago. 

 By means of a torsion balance, hung 

 symmetrically with respect to two magnetic 

 poles and made diamagnetie by superposi- 

 tion of bismuth pieces, the variation of the 

 force of repulsion upon the test pieces 

 examined was measured. From the me- 

 chanical force thus determined and the con- 

 stants of the magnetic field found with an 

 exploration coil, the susceptibility of the 

 specimens was obtained. Within a range 

 of field strengths of from 200 to 600 lines, 

 the bismuth gave the same susceptibility 

 as had been found by other observers with 

 much larger fields. By careful prepara- 

 tion tin was obtained which had a suscepti- 

 bility of + .31 X 10"". A very pure speci- 

 men of native copper was found to have a 

 susceptibility of — 1.22 X 10"". Alloys 

 made from this tin and copper had sus- 

 ceptibilities which were in some cases of 

 higher negative value than that of the cop- 

 per, thus showing in diamagnetism a phe- 

 nomenon altogether analogous to the 

 Heusler phenomenon in paramagnetism. 

 As the per cent, of tin increased from zero 



