Chemistry.and Physics. 167 
It readily becomes red on the addition of acids and is very sensi- 
tive as an indicator for titrition. In alkali-solution it shows a 
broad band in its spectrum near the line D which shades off to- 
ward E. In acid solution, it cuts off the more refrangible portions 
of the spectram.— Ber. Berl. Chem. Ges., xvii, 2615. GF. B. 
9. Use of the induction Spark in Spectrum Analysis.—M. 
Demargay has modified the method of M. Lecoqg de Boisbaudran 
by employing an induction coil made of comparatively large and 
short wire. By means of this induction coil atmospheric lines 
of the second order are not obtained and rarely the nebulous 
layers. The diameter of the wire of the secondary coil was also 
im='and it weighed 3*g-400. The bundle of iron wires was 27" 
tefraction of a peculiar nature exists in a magnetic field in a 
Jrection at right angles to the lines of force. This double refrac- 
tion has not yet been observed; but Cornu shows that the quan- 
tity to be observed is of the order of dimension of a wave length 
and ought therefore to be detected with the powerful means now 
at our command.— Comptes Rendus, Dee. 15, 1884. J. T. 
ll. A new Galvanometer.—J. RosENTHAL describes a new form 
of galvanometer which is said to have great range and great sensi- 
; b : 
d 
dollars novelty consists in the needle which is a ho 
Magnet suspended by a long fiber attached to its neutral point. 
The poles of the magnet are provided with horizontal pole piece 
Which are quadrantal ares of a circle the center of which lies m 
the axis of suspension of the horse-shoe. These pole pieces can 
Play within the axis of two galvanometer bobbins placed on 
u * 
has made to test the sensitiveness of this instrument. Without 
compensation by an exterior magnet O-1™™ deflection corres- 
