■J 8 



EEroRTS ON THE STAtE Of" SCIENCE;. 



other siiiall cliangeti are difficult lo assign and are possibly due to variable 

 humidity. The eri'Ors in the differences recorded are certainly less than 

 1 X 10"*' ohm. 



The above is only part of the analysis of the differences which is in 

 general made. Comparisons with coils other than units are also often 

 desirable, but need not be dealt with here. 



Table XI. gives the resistance of a number of manganin coils in the 

 October of each year from 1903 to 1907, and charts Nos. 1 and 2 show 

 the complete changes in most of the coils from March 1903 to June 190S. 

 In Table XI. the resistances are given in the same month of each year 

 in order to eliminate from the table (as much as possible) the effects of 

 Jiumidity on the resistances of the coils. 



Resistances L19, 2448, and 2449 were placed in atmospheres of vary- 

 ing humidities in the interval October 1907-April 1908, and hence the 

 curves for these coils are not continued on the charts after January 

 1908. 



Table XI. 

 liesistaiices in International Ohms at 17°'0 C. 



At first limiting our attention to the unit coils, we see from the charts 

 that these have varied during the past five years by the following 

 amounts : — 



