208 



capital Greek O) with a critical examination of Herschel's figure of 

 the same. 



The most remarkable discovery of Messrs. Smith and Mason, was 

 that of the junction of the two nebulse, h. 2092 and 2093. These 

 great nebulae, or "milky xvays" are described on several occasions 

 by the elder Herschel, and are also described and figured by the 

 younger. They are distant about two-thirds of a degree from each 

 other. Messrs. Smith and Mason, however, distinctly saw the nebu- 

 lous matter extending from one to the other, making the whole one 

 conspicuous nebula of more than a degree in length, being among the 

 most remarkable in the heavens, and inferior only to the great nebulse 

 of Orion and Andromeda. 



Mr. Mason remarks, that it is difficult to conceive how the com- 

 panion of the nebula trifida, and the junction of the two last men- 

 tioned, should have been overlooked by such observers as the Her- 

 schels, with instruments so far superior to his in optical capacity. 

 The supposition that the nebulous space, noticed by Messrs. Smith 

 and Mason, was not brought under the immediate inspection of the 

 Herschels, seemed inadmissible. That the greater clearness of the 

 atmosphere of New Haven should more than compensate for the in- 

 ferior light of the telescope employed was hardly probable; the only 

 remaining supposition was, that the nebulous matter, in the space 

 examined by all these observers, has recently undergone a change in 

 shape and brilliancy. 



In making the chart of the stars to which the nebulous space is re- 

 ferred, Mr. Mason used the ten feet Dollond refractor, of five inches 

 aperture, belonging to the Philosophical Department of Yale College, 

 with a Dollond's illuminated line micrometer. With this he has de- 

 termined the relative position of the stars down to the 16th magni- 

 tude, by repeated observations, and has furnished a catalogue of the 

 correct places of 15 stars in the first chart, 30 in the second, and 182 

 in the third. 



Dr. Dunglison stated, that the horse, with the filaria in the 

 aqueous humour of the eye, to which allusion was made at the 

 last meeting (See Proceedings, p. 200), was in the city, and 

 that he had had an opportunity of verifying the statement then 

 made. Dr. Dunglison referred to several similar cases, — most 

 of the observers believing the entozoon to be a filaria papillosa, 

 but some a lesser strongylus. 



