230 Scientific Intelligence. 
ph 
which result from the various forms of radiometers, and he there- 
fore adopted the simplest instrument, a single vane suspended by 
a bifilar suspension. Ann. der Physik und Chemie, 1883, No. 
1, pp. 1-32. 7% 
9. Measurement of wave lengths in the Ultra-red portion of 
the solar spectrum.—The peculiarity of this measurement by Ernst 
Pringsheim, resides in the use of a radiometer to measure the 
heat. The spectrum produced by a Rutherfurd’s grating, 17,296 
lines. to the inch, was examined by keeping all parts of the ap- 
paratus stationary except the grating; this was turned upon 4 
vertical axis, and different portions of the spectra were thus 
thrown upon the radiometer. This radiometer consisted of but 
one vane, which was suspended by a long bifilar suspension. The 
radiometer was carefully protected from irregular disturbances 
by being placed in a suitable enclosure. ea . 
apparatus, absorption bands were found from wave length A= 
070013658" to 1=0-0013908"™™. These results were modified by 
the absorbing media which were used to separate the spectra of 
different orders.—Ann. der Physik und Chemie, 1883, No. }, 
Pp 
length of a certain band of fine lines denoting the absence of 
ut ting was e 
ployed and the spectrum was thrown upon various phosphorescent 
esence 
. . f a 
tinctions are known to exist in the ultra-violet.— Comptes Rendus, 
an. 8, 1883, pp. 121-124. sept 
11. Siemens’ Theory of Solar Energy.—M. Favye has pointed 
out that the centrifugal force at the sun’s equator is too feeble in 
comparison with the force of gravity to enable the sun to play 
the role of a machine which takes in matter at the poles and 
throws it off at the equator. Siemens replied to this objection by 
using as an illustration Newton’s tube, which the latter employed 
to show how the flattening of the earth could be determined. ‘This 
a point upon the equator. Faye replies that Newton’s ideal tube 
was supposed to terminate upon the surface of the globe, while 
mt ; 
