4 Harriry & Ramace—Wave-lengths of Principal Lines in Spectrum of Gallium, 
the intensities of the solar lines over a wide scale, extending from 1, a line just 
clearly visible on the map, to 1000, for the H and K lines; and it is remarked that 
this is hardly enough for the enormous differences in intensity. Below 1, the 
lines, in the order of faintness, proceed from 0 to 0000, indicating lines more and 
more difficult to see. ‘The lines in his table which lie near to the two measured 
lines in the are spectrum of gallium are the following :— 
Soiar LInes.* 
r Intensity. 
4171°854, Cr, La, Mn, Ni, Fe, 3 
4172-066, Ti, Fe, Lng a 
AN emtL, AULA), : : : 1 
4172296, Fe, Q 
d 
4032°610, Fe, : ; : : 2 
4032-789, Fe, CONG OAR EAT 4 
40329850 ee Te RETO 0 
4035112, : : ; : ; 00 
4033°224, Fe, Mn,8., . ; 7d. 
We find that the lines in the solar spectrum most nearly coincident with the 
gallium lines, according to our determinations of their wave-lengths, are the 
following :— 
Solar Lines. Intensity. Gallium Lines. Intensity. 
Ue, Nee Tl 4172-214 1 
4035°112, 5 : 00 4033°125 00 
We believe these numbers to be quite accurate to the second decimal place. 
Our micrometer measures to the ten-thousandth of an inch, and an error of this 
magnitude makes a difference of 0:0033 in the wave-length. We used lines in the 
are spectrum as fiducial lines, which correspond with the following solar lines :— 
Sorar Liyes.+ 
4044-766, Fe, 3. 
4040°792, Fe, 3. 
4034-644, Mn-Fe, 6. 
4032-789, Fe, 4. 
4082117, Fe, 2. 
4191595, Fe, 
4187-204, Fe, 
4175:806, Fe, 
4171-068, Fe, 
4143572, Fe, 
a> fo SX Sa. SP 
* Astrophysical Journal, vol. i. 1895. 
+ Corrected by Rowland, and definitely assigned to aluminium. See the Astrophysical Journal, 
December, 1897. 
{ Astrophysical Journal, vol. i., February and March, 1895, and vol. vi., December, 1897. 
