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XIV. On the Specific Resistance of Mercury. 



By R. T. GLAZEBROOK, M.A., F.R.S., Fellow of Trinity College, and T. C. FITZPATRICK, 

 B.A., Fallow of Christ's College, Demonstrators o.t the Cavendish Laboratory, 

 Cambridge. 



Received Jane 19, Read Jane 21, 1888. 



[PLATE 19.] 



OF late years several determinations of the electrical resistance of mercury have been 

 made, and the differences between the results arrived at have been greater than would 

 be expected at first sight from the nature of the observations involved. The results 

 of the experiments have been expressed either in terms of the ohm (10 9 absolute 

 C.G.S. units) or of the B.A. unit, which, according to the determinations of Lord 

 RAYLEIGH and one of the authors of this paper (R. T. G.), is equal to '98667 ohm. 



Iii the case of Lord RAYLEIGH'S observations, a direct comparison was made between 

 the mercury unit and the original B.A. standards. Other observers have constructed 

 copies of their mercury resistances in German-silver wire, which have been com- 

 pared with the B.A. standards at the Cavendish Laboratory by one of us, or have 

 compared their tubes directly with copies in platinum-silver wire of the B.A. units 

 which have been sent from Cambridge after careful testing. The result of these 

 various comparisons of recent years is as follows, and may conveniently be put in 

 tabular form, giving the value in B.A. units of the resistance of a column of mercury 

 1 metre long, 1 square millimetre in cross section, at Centigrade. 



This is done in Table I., which also gives the value as found by various observers of 

 the resistance of I ohm expressed in centimetres of mercury at C. 



28.11.88 



