546 Progress in Science. (October, 
Mr. John Evans (President of the Geological Society), and Prof. Prestwich— 
make an earnest appeal for further assistance to carry on the work. 
The Steppes of Siberia.—Mr. Thomas Belt has described some seions 
examined by him on a portion of the Siberian steppes, which have enabled 
him to form an opinion as to the origin of the great plain. The best section 
seen by him was at Pavlodar, which showed 50 feet of sand and silt, with 
occasional lines of pebbles. South of Pavlodar the surface of the ground was 
covered with pebbles, which became larger in advancing southward, until the 
soil was full of large angular quartz boulders. Further south the bed-rock 
comes to the surface in ridges and low hills, increasing in height until some 
of them ‘attain 2000 feet. All the rock-surfaces were much shattered, as if by 
the action of frost, but they showed no signs of glacier-action. The generally 
accepted marine origin of the great plain was said to be negatived by the 
absence of sea-shells in its deposits, whilst Cyrena fluminalis occurs in them. 
The author regards them as deposits from a great expanse of fresh water kept 
back by a barrier of polar ice descending far towards the south. In its greatest 
extension this ice-barrier would produce the crushing of the bed-rock; and as 
it retreated, the water coming down from the higher ground in the south would 
cover a continually increasing surface. The distribution of the boulders on 
the plain north of the ridges was attributed to floating ice. 
Professor of Geology at Oxford.—Mr. Joseph Prestwich, F.R.S., &c., has 
been appointed to the office of Professor of Geology in the University of 
Oxford, as successor to the late Prof. Phillips. The Council of the Institution 
of Civil Engineers have recently awarded to him a Telford Medal and 
Premium, for his paper ‘‘On the Geological Conditions affecting the Con- 
struction of a Tunnel between England and France.” 
Dr. F. Stoliczka.—Paleontological Science has lost one of its ablest 
students in the death of Dr. Stoliczka, at the early age of 34. He is known 
chiefly through his connection with the Geological Survey of India, by his 
descriptions of many of the fossil organic remains collected by the Staff. For 
several years he was Natural-History Secretary to the Asiatic Society of 
Bengal, and itis mainly to his exertions that this Society owes the resumption 
of much of its early vigour. 
PHYSICS. 
Licut.—M. Rayet has published a ‘‘ Note on the Spectrum of Coggia’s 
Comet.”” On May 1g the light gave a continuous spectrum from the orange to 
the blue (spectrum of solid nucleus) traversed by three bright bands (spectrum 
of gaseous nebulosity) ; but the continuous spectrum was very narrow com- 
pared with the ordinary nuclear spectra; and the luminous bands, instead of 
being stumped towards the more refrangible side, terminated, towards red and 
violet, in very distiné straight lines. Father Secchi also writes: On June 18 
and 1g the spectrum with the bands of carbon was considerably developed, 
the green band remaining the more distin&, whilst in the comet of Temple 
the yellow was brightest. This proves that the gaseous compounds are not 
the same in all comets. At the beginning of the month there was merely a 
spectrum of bands, now there is a general connecting line which unites them 
into one continuous spectrum. ‘The bands of the comet are more diffuse than 
those of carbonic oxide. They resemble the spectrum obtained by the electric 
spark in the vapour of benzine. 
A new helioscope has been construéted by M. Prazmowski. The idea of 
employing the polarisation of light in place of coloured glasses to diminish 
the lustre of the sun is not novel; but the quantity of light reflected, even 
under the Brewsterian angle for glass of a low index (1 =1°'5) is so considerable 
that the eye cannot support the light. The author obviates this difficulty by 
taking a rectangular prism of an index, 2, and cementing upon its hypothenuse 
another similar prism, so as to form a cube. The index of the second prism 
isn'. A ray of light meets in its course the first hypothenuse of the cemented 
take Beate Ras : Sede. n : 
pair with an incidence of 45°; this is the surface whose index is _. As — is 
oe n n 
