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XXII. Intelligence and Miscellaneous Articles. 



ON THE MOTION OF AN INCOMPRESSIBLE VISCOUS FLUID IN THE 

 VICINITY OF A SPHERE. 



To the Editors of the Philosophical Magazine and Journal. 



I 



Gentlemen, Halle a. S., Dec. 29, 1880. 



X the Xovember number of the Philosophical Magazine (vol. x. 



No. 63), pp. 342-357, is a paper by Dr. Thomas Craig, of Wash- 

 ington, communicated by A. Gr. Greenhill, Esq., " On Steady 

 Motion in an Incompressible Viscous Fluid." The second part of 

 that paper treats of the motion of the fluid in the vicinity of a 

 sphere. In the year 1875, in Borchardt's Journal fur reine und 

 angewandte Mathematilc, vol. lxxxi., I discussed the same question : 

 I place at your disposal the enclosed copy of my paper. You will 

 easily convince yourselves, by the perusal of § 2 (pp. 68-74) of the 

 same, that : — 



(1) Mr. Craig and I have set and discussed exactly the same 

 problem ; 



(2) There is a close correspondence between the transformations 

 and calculations in the one paper and in the other (I mention 

 especially that Dr. Craig likewise makes use of a theorem of Bor- 

 chardt's, Monatsberichte der Berl. AJcad. 1873, in the same way as 

 I had done) ; 



(3) Of course our final results are identical. 



I therefore venture to hope that you will give as early insertion 

 as possible to this in the Philosophical Magazine. 



Dr. A. Obeebeck, Professor at the 

 University of Halle a. d. Saale. 



ON THE MEASUREMENT OF THE ELECTROMOTIVE FORCE OF THE 

 PILE. BY M. J.-B. BAILLE. 



The relative electromotive force of the pile is usually deduced 

 from Ohm's laws and the examination of the intensity of the cur- 

 rents produced by it. When one wishes to measure these forces 

 directly and to express them in absolute value, the very ingenious 

 apparatus of Sir W. Thomson is ordinarily employed ; but these 

 instruments require delicate management, and the indications given 

 by them are not always free from doubt. The study which M. 

 Cornu and I have made of the torsion-balance for our experiments 



Phil. Mag. S. 5. Vol. 10. No. 6Q. Feb. 1881. M 



