SCIENTIFIC SUMMARY. 
329 
ing the quickness of motion of the balloon on leaving the earth, and at such 
times there is no doubt that the real less reading at 100 ft. high was very 
much greater. On the contrary, in some of the ascents, a decline of 8° to 
10° was met with within 1,000 ft. of the earth (see ascents of July 30, 1862 ; 
August 18, 1862, &c.), whilst in others but little or no difference was found 
within 1,000 ft. of the earth ( see June 13, 1864) ; and again, in others at night, 
the air was of higher temperature on ascending. From all Mr. Glaisher’s 
observations in the free balloon, it was found that the change of temperature 
near the earth varied greatly, and that it followed no constant law. 
Mr. Joule in the French Academy. — At the meeting of the French Academy 
on the 30th ult., when Mr. Joule was elected to the place vacant by the 
death of M. Magnus as correspondent in the Section of Physics, the follow- 
ing was the return of the secret committee : — In the first line, Mr. Joule, of 
Manchester. In the second line and in alphabetical order, MM. Angstrom, 
of Upsala; Billet, of Dijon; Dove, of Berlin; Grove, of London; Henry, 
of Philadelphia ; Jacobi, of St. Petersburg ; Lloyd, of Dublin ; Ries3, of 
Berlin ; Stokes, of Cambridge ; W. Thomson, of Glasgow ; Tyndall, of 
London; and Volpicelli, of Rome. Forty-three members took part in the 
election, with the following result: — Mr. Joule, 32 votes; Dr. Lloyd, 8; 
MM. Angstrom, Dove, and Volpicelli, one vote each. 
Electric Currents caused by Contact of Metals and Distilled Water. — The 
Comptes-rendus for May 2 contains a paper by M. E. Becquerel on this 
point. The following are the results arrived at. The electrical effects pro- 
duced by the contact of non-oxidisable metals and distilled water (chemically 
pure) are due, not to any special action of contact, but to the reaction of the 
water upon the gases condensed on the surface of these metals. The effects 
vary according to the molecular state of the metals and their temperature. 
As regards, however, the oxidisable metals, the electrical effects produced 
by heating them are due to the very slight layer of oxide adhering to their 
surface, whereby they are rendered positive towards the unpreserved metallic 
surface. 
A New Salt-Water Galvanic Pile was described by M. Duchemin at the 
meeting of the Academy of Sciences of Paris on June 6. 
The Leclanche Cell. — This cell, which is largely used in the batteries of the 
French telegraphic system, is thus reported on by Professor Morse : — “ This 
battery consists of a prism of carbon for its positive pole, which is surrounded 
by a mixture of peroxide of manganese and carbon pulverised, filling the 
porous jar. . This jar is put into the glass jar containing a solution of sal 
ammoniac ; within the same glass jar and solution is a prism of amalgamated 
zinc, forming the negative pole. Its action is thus : On closing the circuit, 
the sal ammoniac is decomposed, the chlorine of the solution is absorbed by 
the zinc, the negative pole ; while the hydrogen and the ammonia pass to 
the positive pole, reducing the peroxide of manganese. According to the 
inventor’s explanation, 1 the peroxide of manganese mixed with carbon being 
a good conductor of electricity, the system may be considered as a single 
fluid element, in which the positive pole is formed of an artificial metal 
having a great affinity for hydrogen.’ ” 
Supra-Annual Cycles of Temperature in the Earth's Surface Crust. — In a 
paper laid before the Royal Society in April, Professor C. Piazzi Smytb, 
