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POPULAR SCIENCE REVIEW. 
dency of General Baeyer, set to work to execute, in the Helvetian Republic, 
a complete and very accurate taking of levels and measuring of altitudes 
above sea-level, and other geodesical labours. The observatory at Berne is 
situated at 572T4 metres above sea-level ; the cathedral of Fribourg at 
588‘66 metres ; the town-hall at Chaux-de-Fonds at 989‘35 metres. 
Physics at Cambridge. — We learn from a contemporary that the difficulty of 
providing funds for the establishment of a Professorship of Physical Science 
in the University of Cambridge has been overcome by the colleges, at a 
meeting of their heads, taking upon themselves a quota of the rates for im- 
provements and other purposes in the town of Cambridge, which was 
formerly charged upon the University funds. This sum amounts to more 
than twelve hundred pounds per annum ; so that the University will speedily 
be able to avail itself of the munificent offer of the Duke of Devonshire, and 
will doubtless proceed at once to establish a Professorship of Physical 
Science, and obtain the other aids in the way of laboratory, apparatus, and 
assistants, that the Professor may require. 
Physics at Oxford. — It is now stated that the Physical Laboratory lately 
built at Oxford is opened this term for practical instruction in physics, under 
the superintendence of Professor R. B. Clifton, F.R.S., assisted by two 
demonstrators. 
The Laws of Distillation. — It is a fact that volatility alone does not deter- 
mine which of mixed liquids will distil over first. Quantity has something 
to do with it. If the less volatile be in large excess, it tends to come over 
with the other. But there is still another law. The comparative density of 
the vapours produced affects the result, the denser vapour having a ten- 
dency to be evolved in greater quantity. Dr. Van der Weyde thus closes a 
recent paper : — u These facts prove that the amount of vapour developed from 
liquids is regulated by volume and not by weight, or, in other words, that 
of two liquids possessing the same boiling point, but of which the densities 
of the vapours differ, the same volumes of vapours will evolve, and that, 
consequently, the liquid emitting the densest vapour will evaporate in larger 
quantity ; or that if there be two liquids of which the boiling points differ, 
and that with the lowest boiling point possesses the lightest vapour, the 
greater volume of the vapour generated from the latter will produce less 
liquid after recondensation than the lesser volume of the vapour evolved 
from the less volatile liquid, the latter thus more than compensating the 
former, and resulting in the apparent anomaly that from a mixture of two 
liquids of different boiling points the least volatile may sometimes distil 
over in the largest quantity.” 
The Laics of Electric Batteries. — Mr. H. Ilighton contributes to the 
a Chemical News,” Dec. 2, some novel ideas on the subject of electric bat- 
teries. He is evidently working the subject out in its right vein — dividing the 
time during which the battery acts into three periods. He thus describes them. 
(1) The time which it takes the electric force to traverse the circuit after it 
is closed. This in ordinary cases is infinitesimal ; but where the circuit is 
very long, and where there is much inductive as well as conductive resist- 
ance, as in the Atlantic telegraph, the time becomes very appreciable. But 
he would remark that the expenditure of zinc during this first period is 
occupied in producing a state of tension in the conductor which, theoretically 
