56 E. J. CHAPMAN : NOTE ON SPECTROSCOPE SCALES. 
the sodium and the dark-red potassium-line. In another (a common chemical) spectroscope, 
these distances are respectively 8 and 15. The reduced or corrected potassium number (as 
regards the red K line) would be thus in each case 19 nearly. 
[Se O34 was oe: 
So Mee iss Ts 
If the Hthium line be objected to, as not being coincident with any main solar-line, 
the red potassium-line might be taken for the second fixed point, as this is closely coincident 
with the A line of the solar spectrum ; and the distance between this and the sodium line 
might be made equal to 20, or 100, or any other convenient number of scale divisions. The 
object of this Note is to obtain the sanction of the Royal Canadian Society to the scheme 
which the Note embodies: or, otherwise, to elicit from our Section of the Society some more 
feasible method of meeting the deficiency to which the Note refers. 
