Chemistry and Physics. 257 
double star; orange oil and mixtures of turpentine gave results 
similar to those obtained with sugar i er 
shown to be polarized in different planes, and the author believes 
that he is justified in concluding that there are doubly refracting 
finids which have no optical axes; and that circular polarization 
in liquids is due to this double refraction. e wave surfaces o 
light in these liquids consist of that of two concentric spheres.— 
Ann. der Physik und Chemie, No. 1, 1885, pp. 127-144. 3. T. 
14. Penetration of day light in the water of Lake Geneva.—MM. 
For and Ep. Sarasty’s experiments consisted in exposing photo- 
graphic plates at various depths in the lake. They used Monck- 
hoven’s rapid gelatino-bromide plates. The special apparatus 
consisted of a brass photographic holder, the slides of which were 
closed by a pair of levers joined like scissors, and actuated by a 
weight. These levers separate by means of a counter acting spring 
the water. The time of exposure was always ten minutes. ie 
goblet he placed a copper spiral which is connected with an insu- 
lated platinum wire in a glass tube. Above the spiral is placed 
lay the solation of white sulphate of zinc in which was placed the 
rine eylinder. A siphon, the outer leg of which was directed from 
below upwards, dipped into the fluids as far as the bounding plane 
of the two fluids, so that, on filtering in a fresh solution, only the 
‘olution of white vitriol immediately above the blue copperas, and 
Contaminated by it flowed off. This arrangement had the effect 
keeping the upper fluid constantly water clear, though after a 
While some copper was found precipitated upon the zine cylinder. 
he constancy of the cell was however not perceptibly impaired.— 
Nature, January 29, J Be 
