70 
LORD OXMANTOWN ON THE GREAT NEBULA IN ORION. 
December 4th, 1861. — “ I thought I could resolve the Huygenian region at v, £, and /.” 
February 22nd, 1862. — “ 3-feet speculum newly polished shows it much better than 
the former, indeed better than the 6-feet now in the tube. The part round the .trape- 
zium looks just like fine flour scattered over a grey surface, so that 1 have no hesitation 
in saying that it is composed of stars, many small ones seen through it,” &c. 
January 12th, 1864. — “ The knots y, $, s, v are, I think, resolved”*. 
February 3rd, 1864. — “ z is decidedly resolvable, / is also resolvable; I believe about 
Q is also resolvable”*. 
February 4th, 1864. — “At moments I could see stars through the Huygenian region 
glancing, and I have no doubt that all the bright knots of it are resolvable ; at z, l, s, y 
I saw clearly at least one star in each, and at & I believe for a short time I saw its stars 
separated.” The little knots opposite r and a have each a resolvable look. 
March 1st, 1864. — “The Huygenian region is clearly resolved ; I could see the indi- 
vidual stars, though I could not count them ; the stars are well separated in the trian- 
gular knot C6. I strongly suspect the region at 113 m is resolved, especially at the edges 
of the bay.” 
March 10th, 1864. — “ Saw stars clearly at <r and at v*, at intervals also around 113 m .” 
March 24th, 1864. — “ Huygenian region clearly resolved.” 
From these observations we may conclude that there are multitudes of small stars in 
the whole of the bright parts round the trapezium, and also at 11 3 m . Mr. Hunter makes 
no mention of resolvability in the proboscis major, but he has marked the preceding edge 
from 126 to about 80'" below this star as resolvable. All the parts which have this 
appearance are marked over in the drawing with dots of Indian ink, and the rest of the 
nebula was done with a stump and blacklead pencil. It was, however, found almost 
impossible to reproduce this difference of appearance in the engraving, since the whole 
of the surface consists of minute black dots. 
This resolvable appearance can be seen on good nights only, and with a very good 
speculum. 
We now come to the last part of our subject, the knowledge of the nature of this 
nebula acquired by the use of 
The Spectroscope. 
Very little has been done with this instrument as yet. The clock-movement for the 
six-feet telescope is not yet finished, and consequently it is impossible to keep the slit 
steadily on any small object; we have, however, obtained the spectra of about twelve 
objects, and our results, as far as they go, fully confirm those of Mr. Huggins, namely, 
that some nebulse give gaseous spectra, consisting of one, two, or three bright lines, 
while others give faint continuous spectra in their brighter parts. The telescope which 
was generally used was the three-feet, in the Herschelian form; of course without 
clock-movement. This instrument was found on the whole more convenient than the 
six-feet, as it could be kept with greater ease on the object. 
The following was the method of observation employed. One observer kept the ob- 
* See diagram, p. 67. 
