104 M. A. F. Sundell on Absolute 



thus obtain for the density of water the number 



_6_ 615 1 _6-7 1 

 5-5 X l0 w sec. 2 ~10 8 sec. 2 ' 



which agrees exactly with Thomson and Tait's number. It is 

 to be observed that the dimensions of the electric and magnetic 

 units in this system have exponents which are whole numbers. 

 In the Gauss- Weber system the dimensions of [/u.] and \e~\ are 



the same as of [m] ; for i we have the dimensions -5 , for [E'] 



[p-i U J 



-g , and so on. 



Example 8. — The Weber unit of current 



_ 1 mm. 2 " x mgr. 2 _ 1 metre 2 x kilogr.^ 

 sec. io» sec. 



\A>15 / \/615\ metre 2 , ,. ... 



10*xl0 



If we wish to return to the ordinary system, we must observe 

 equation (44). We may calculate as follows : — 



a/615 metre 2 ,, x a/615 metre* w metre^ 



— nvn §~ (current-strength) = —r-^pp X 



10 n sec. 2 v 6 y 10 11 sec. sec. 



_ a/615 / metre 3 \i metre 2 _ a/615 

 10 u V sec. 2 / X sec. ~ 10 11 



10t kilogr.2 x metre^ . ,,_ 1 metre 2 x kilogr.£ 

 •v/615 sec. ^ i- '~10* second 



(Weber unit of current). 

 The constant of attraction may also be eliminated by putting 



/615 metre 2 \/615 millimetre 2 

 1 second =V ^ ^—j = - w milHgri , 



so that the unit of time becomes a unit derived from the unit 

 of length and the unit of mass, 



, metre 1 /lO 13 , 



1 j = \ / 7TTF seconds. 



kilogri V 615 



m, ., o r -, metre x kilogr. . 10 13 kilogr.'* 



Ihe unit of force 1 ia & - becomes 77^ P-s-, 



second" 1 615 metre 2 ; 



