PROFESSOR IN BERLIN 333 



my audience, and therefore go on flinging my bad French in 

 their faces.' 



From Paris, Helmholtz returned by Florence and Vienna 

 (where he and Sir W. Thomson visited the Electrical Ex- 

 hibition) to Berlin, and proceeded to report on the decisions 

 of the Paris Congress in written memoirs and addresses to 

 various Scientific Societies. Before the end of the year he 

 entered more precisely into the results of the proceedings in 

 a lecture to the Electro-Technical Union, ' On the Electrical 

 Units as determined by the Electrical Congress assembled in 

 Paris, i88i/ and in another given the following year to the 

 Physical Society in a ' Report on the Proceedings of the Inter- 

 national Electrical Commission ', which were summed up in his 

 article ' On Absolute Systems of Measurement for Electrical 

 and Magnetic Magnitudes ' in Wiedemann's Annalen for 1882. 



Helmholtz had now practically finished his fundamental 

 researches in thermodynamics, and was engaged on the 

 difficult problem of preparing them for publication. At the 

 same time he was directing various pieces of experimental 

 work, which were of especial theoretical interest to him in 

 establishing his chemical views. 



On November 3, 1881, he presented a paper to the Academy 

 'On the Galvanic Polarization of Mercury, and some new 

 Experiments of Herr Arthur Konig relating to the same/ 

 which Konig had carried out in the University Laboratory 

 under Helmholtz's direction. Their purpose was to determine 

 the capillary tension of galvanically polarized surfaces of 

 mercury, in which the disturbing influence of the alterable 

 adhesion of the two fluids to the glass walls was eliminated. 

 The optical difficulties in measuring the difference in level 

 between the top and the maximal circumference of a quiescent 

 drop of mercury were also avoided, and the measurement of 

 the surface-tension of the quicksilver was obtained by observing 

 the curvature of the summit of a drop of mercury, which could 

 be determined with the greatest precision by the ophthal- 

 mometer. The drop projected from the upper circular opening, 

 9 mm. in diameter, of a glass vessel, and was surrounded by 

 the electrolytic fluid contained in a wider vessel. By a special 

 arrangement the top could be more or less protruded from the 

 mouth of the narrow vessel, and arranged in such a way 



