ME. W. HTJGGINS ON THE SPECTKA OE SOME OE THE NEBULjE. 441 
In the spectrum of this nebula, however, in addition to the three bright lines, a fourth 
bright line, excessively faint, was seen. This line is about as much more refrangible 
than the line agreeing in position with F as this line is more refrangible than the 
brightest of the lines, which coincides with a line of nitrogen. 
[No. 4532. 2060 h. 27 M. R.A. 19 h 53™29 s -3. N.P.D. 67° 39' 43." Very bright ; very 
large ; irregularly extended. Dumb-bell.] In Vulpecula. 
The light of this nebula, after passing through the prisms, remained concentrated in a 
bright line corresponding to the brightest of the three lines represented in fig. 5, Plate X. 
This line appeared nebulous at the edges. No trace of the other lines was perceived, 
nor was a faint continuous spectrum detected. 
The bright line was ascertained, by a simultaneous comparison with the spectrum 
of the induction spark, to agree in position with the brightest of the lines of 
nitrogen. 
Minute points of light have been observed in this nebula by Lord Posse, Otto Struve, 
and others ; the spectra of these bright points, especially if continuous like those of 
stars, are doubtless invisible from excessive faintness. 
By suitable movements given to the telescope, different portions of the image of the 
nebula formed in the telescope were caused successively to fall upon the opening of the 
slit, which was about inch by - 3 ^ inch. This method of observation showed that 
the light from different parts of the nebula is identical in refrangibility, and varies alone 
in degree of intensity. 
In addition to these objects the following were also observed: — 
[No. 4294. 92 M. P.A. 17 1 ' 12™ 56 s -9. N.P.D. 46° 43' 31"-2.] In Hercules. Very 
blight globular cluster of stars. The bright central portion was brought upon the slit. 
A faint spectrum similar to that of a star. The light could be traced from between C 
and D to about G. 
Too faint for the observation of lines of absorption. 
[No. 4244. 50 H. IV. R.A. 16 h 43™ 6 s -4. N.P.D. 42° 8 ' 38"-8. Very bright; large; 
round.] In Hercules. The spectrum similar to that of a faint star. No indication of 
bright lines. 
[No. 116. 50 h. 31 M. R.A. 0 h 35™ 3 s -9. N.P.D. 49° 29' 45"-7.] The brightest part 
of the great nebula in Andromeda was brought upon the slit. 
The spectrum could be traced from about D to F. The light appeared to cease very 
abruptly in the orange ; this may be due to the smaller luminosity of this part of the 
spectrum. No indication of the bright lines. 
[No. 117. 51 h. 32 M. R.A. 0 h 35™ 5 S, 3. N.P.D. 49° 54' 12"*7. Very very bright ; 
large ; round ; pretty suddenly much brighter in the middle.] 
This small but very bright companion of the great nebula in Andromeda presents a 
spectrum apparently exactly similar to that of 31 M. 
The spectrum appears to end abruptly in the orange; and throughout its length 
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