498 
NAT 
iad 
CE [| Marcu 25 
1897 
America, presented by Mrs. Dade; two Brown Mud Frogs | 
(Pelobates fuscus) from Italy, presented by Count M. Peracea ; 
an Indian Elephant (Z/ephas indicus, 9) from India, a Rose- 
crested Cockatoo (Cacatwa moluccensis) from Moluccas, de- 
posited ; a Chimachima Milvago (A%i/vago chimachima), two 
Violaceous Night Herons (Wyctecorax violaceus) from South 
America, a Common Quail (Coternix communis) captured at 
sea, a Common Rhea (Rhea americana) from South America, | 
a Bornean Gibbon (Ay/obates mueller?, 2) from Borneo, 
purchased. 
OUR ASTRONOMICAL COLUMN, 
THREE BRILLIANT STELLAR SysTEMS.—Prof. T. J. J. See, | 
with the aid of the 24-inch refractor of the Lowell Observatory, 
in Mexico, has recently discovered (Astv. Journal, No. 396) 
three objects which ‘‘may be regarded as amongst the most 
splendid systems in the heavens.” The first, discovered in | 
January last, is a Phoenicis, its position for 1900 being R.A. oh. 
2Im. 19'5s., decl.—42° 50’ 48”*1. The primary of this 
double has a magnitude of 2°4, the companion being as faint asa | 
thirteenth mag. star. This inequality, combined with the deep 
orange or reddish colour of @ Phoenicis, renders the system both 
striking and difficult. The mean of some measures made for | 
determination of the position of the components was 1897°041, 
pos. angle 272°°7, dist. 9'°73. The second of these objects, 
also a very southern star, is « Velorum with a magnitude of 
nearly 3, the companion being 11, of a purplish colour and very 
near the large star. [R.A. toh. 42m. 28s., decl.—48° 53’ 
31” (1900)]. This system is described as one of the most 
extraordinary in the heavens, and likely to have a very large 
orbital motion. Measurements of position gave for 18977059, 
pos. angle 62°°7, dist. 2”°54. The third and last of these 
objects, 7 Centauri,’ situated at R.A. 14h. 29m. Ios., and decl. 
ON THE INFLUENCE OF RONTGEN RAYS 
IN RESPECT TO ELECTRIC CONDUCTION 
THROUGH AIR, PARAFFIN, AND GLASS} 
YWVVE have in previous papers described experiments respecting 
" electric conduction when Rontgen rays fall on metals, 
positively or negatively electrified to potentials of two or three 
volts. We found that although air is rendered conductive, 
paraffin and glass are not rendered sensibly conductive when 
the differences of potential concerned are not more than two or 
three volts per centimetre of air, or per centimetre of paraffin, 
or per half-millimetre of glass. 
We have now to describe an extension of the investigation to 
much higher voltages, in which we use an arrangement of two 
(quasi) Leyden jars, A and B, with their inside coatings con- 
nected together. The outside coating of A was connected to 
sheaths, the outside of B to the insulated terminal of the electro- 
meter. In all the experiments to be described, B remained the 
same. 
It consisted of a cylindrical lead can, 25 cms. long, 4 ems. 
diameter. A metal bar about I cm. diameter, 25 cms. long, 
| was supported centrally on paraffin filling the whole space be- 
This metal bar was con- 
tween it and the containing lead. 
To protect this 
nected by a wire to the internal coating of A. 
VLR 
{a a 
VILL xxzz_xAQAQKE} 
wire from inductive effects, it was surrounded by a tube of lead 
connected to sheaths. . , 
The Leyden A, which was placed opposite the Rontgen 
| lamp, was different according as we were experimenting on 
| the discharge through air, through paraffin, or through glass 
To get a definite difference of potential, the two pairs of 
quadrants of the electrometer were first placed in metallic 
connection. Then one terminal of a battery or of an electro- 
| static inductive machine was connected to the internal coatings 
—41° 42’ 59” (1900). The components are of magnitude 2°5 and 
13°5, being yellow and purple in colour. The system is described 
as extremely difficult, requiring a powerful telescope to see it. 
The relative positions of the components is given for 1897051, as 
pos. angle 270°'1, dist. 5’’°65. 
THE Companion 10 PRocyoN.—To those who wish to seek 
for the companion to Procyon, Prof. Schaerberle’s description of 
the method he adopts (As/7, Muchr., No. 3410) in observing this 
faint companion will prove of service. Owing to its very close 
proximity to Procyon, the companion can only be seen when the 
observing conditions are at their best. If a good objective be 
employed the aperture should not be reduced, but a cap fitted 
over the eyepiece is found most serviceable. For Prof. Schae- 
berle’s measures an eyepiece magnifying 500 diameters was 
employed, the aperture of the cap over the eyepiece being 
about 1°6 millimetres. The magnitude of this companion is 
estimated as fully equal to a twelfth-magnitude star, and when | 
the seeing is good it is ‘‘as easily and accurately measured as | 
the satellite Phobos when Mars is in opposition.” Sirius’ com- 
panion is estimated as being two or three magnitudes brighter | 
than that of Procyon, and is also being regularly observed at the | 
Lick Observatory, the same means—namely, cap over the eye- | 
piece—being employed. | 
NO. 1430, VOL. 55] 
of the jars, and the other terminal to sheaths. The difference 
of potential produced was measured by a multicellular volt- 
meter in the case of differences under 500 volts, and on a 
vertical single vane voltmeter for higher differences. ; 
When the desired difference of potential had been established ,. 
the metallic connection of the battery or electric machine with 
the internal coatings of A and B was broken, and this charged 
body left to itself. To find the loss due to imperfect insulation, 
the pair of quadrants in metallic connection with the outside 
coating of B was insulated in the ordinary way, and the devia- 
tion of the electrometer reading from the metallic zero per half- 
minute was observed. To find the loss when the rays were 
acting, the two pairs of quadrants were again placed in metallic 
connection, the Réntgen lamp set a-going, then the pair of 
quadrants connected to the outside coating of B Was insulated 
from the other pair, and the deviation from metallic zero again 
observed per half-minute. 
In the experiments with air, the Leyden A consisted of an 
aluminium cylinder, 16 ems. long, 3 cms. in diameter. This 
cylinder projected beyond the lead tube, and was connected to 
sheaths. The insulated metal inside it, which was a flat strip 
1 By Lord Kelvin, Dr. J. Carruthers Beattie, and Dr. M. Smoluchowski 
de Smolan. Read before the Royal Society of Edinburgh, March 1. 
