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Mr. C. W. Vincent on the Relations of 



Gay-Lussac* observed the depression of mercury in a tube 

 wetted with water or aqueous alcohol, and found the following 

 results, which, with the values of a ou cos co ou calculated accord- 

 ing to equation (17), § 19, are collected in the following Table. 

 The values of a given therein were calculated from measure- 

 ments made by Gay-Lussacf. 



Table XXI.— Elevations in Capillary Tubes. Two Liquids. 

 Water; Mercury. 

 j cr = l, <r M =13-6, 



2a = 15*13 mgrms., {oc ou = 42*58 mgrms.). 



2r. 



ho' 



hu- 



"Erhv. 



OCou COS h)OU- 



9ou- 



millim. 

 06472 



millim s. 

 7-730 



millims. 

 -7415 



mgrms. 

 -60-23 



mgrms. 

 -37-68 



O 1 



27 15 



Alcohol j Mercury. 

 <r =O8197, a u = lS'6, 

 2a =4*984 mgrms., (a oa = 40*71 mgrms.). 



0-6472 



7-473 



-8-026 



-66-65 



-35-81 



28 36 



It is seen that these numbers agree well with the determina- 

 tions obtained from observation of flat drops of mercury (Table X. 

 § 10). But the angle co ou in the experiments by Gay-Lussac for 

 mercury and alcohol is not to be put = 180°. 



[To be continued.] 



LI. On the Relations of Magnetism and Static Electricity. 

 By^ Charles W. Vincent J. 



IT was not the writer's intention to contribute to the Philo- 

 , sophical Magazine on the above subject in the present 

 Number ; but an error of rather a serious character in his last 

 Communication compels him to add a few lines to it. 



At page 300 and at page 302, he describes a pointed iron wire 

 and a pointed magnetic needle as becoming inductively charged, 

 at the point with positive, at the thick end with negative elec- 

 tricity ; that (as he need hardly tell electricians) is not so. The 



* Laplace, Mec. Cel. vol. iv. p. 496. Poisson, Nouv. Theor. p. 147. 

 f Poisson, Nouv. TMor. p. 113. Laplace, Mec. Cel. vol. iv. p. 524. 

 X Communicated by the Author. 



