ON PRACTICAL STANDARDS FOR ELECTRICAL MEASUREMENTS. 55 



amalgam is fused and its surface flooded with very dilute sulphuric acid ; 

 sufficient of it to cover the amalgamated platinum wire completely should 

 then be introduced into one of the limbs of the H vessel. To fi-ee from 

 acid the amalgam may be remelted and washed with distilled water. Into 

 the other limb of the vessel sufficient mercury is introduced to cover the 

 amalgamated platinum wire completely. Then the paste, finely powdered 

 crystals of cadmium sulphite, and saturated cadmium sulphate solution 

 are added in the order named and the cell sealed. 



Its electromotive force at 20^" 0. is I'OlSj volt. 



The electromotive force at any other temperature (t) may be obtained 

 from the equation : — 



E,=l-0185-0-000038 («-20)-0-00000065 (t-20y, 

 the limits of temperature being — (these have not yet been fixed). 



Magnetic Observations at Falmouth Observatory. — Ueport of the 

 Committee, consisting of Sir W. H. Preece {Chairman), Dr. R. T. 

 Glazebrook {Secretary), Professor W. G. Adams, Dr. Chree, 

 Captain Creak, Mr. W. L. Fox, 8irA. W. Rucker, awci Professor 

 Schuster, 



The results of the magnetic observations at the Falmouth Observatory 

 have been published in the Annual Report of the National Physical 

 Laboratory, as well as in that of the Royal Cornwall Polytechnic 

 Society. 



The mean values of the magnetic elements for the year 1907 were : — 



Declination, . . . 18° 0''4 W. 



Horizontal Force . , 0-18799 C.G.S. 



Vertical Force , . . 043330 CG.S. 



Inclination . . . .66° 32' 7 N. 



The Observatory has been inspected by Mr, T. W. Baker, who found 

 the instruments recording satisfactorily. He also took some absolute 

 observations, which accorded well with those taken by Mr. Kitto. 



The Committee are informed that the observatory at Eskdalemuir has 

 only commenced work during the current year, so that comparative 

 results are not yet available, while the disturbances due to electric 

 traction in the neighbourhood of London have a natural tendency to 

 increase. The maintenance of magnetic work at Falmouth in full 

 efficiency has thus lost none of its importance. It is most desirable to 

 secure this for at least another year, and the Committee ask for 

 reappointment, with a grant of 50^. 



