28 



stated that no alteration has taken place in the star v or its 

 .surrounding nebula since Sir John Herschel was at the Cape." 

 Was it here Mr. Severn changed his mind when he wrote to 

 the Astronomer Royal ? 



In the Enghsh Mechanic, '^o. 352, December 2ord, 1871, an 

 article from Mr. Procter appeared, in which (after using a 

 not very scientific term) he states his belief that he has found 

 out the cause of this imaginary discovery ! After carefully 

 examining tlie evidence adduced he found the result to be 

 that Mr. Abbott's field was 1 degree 7 minutes in extent, while 

 Sir John Herchel's drawing embraced a space of 28 minutes 

 in polar distance, and 32 minutes in arc of light ascension, 

 and this he considers to cause all the confusion. Mr. Procter 

 is under a great mistake if he thinks that either the size of 

 the telescope, or the diameter of the field will prevent the 

 effect of any alterationr, which may have taken place in the 

 nebula, being seen. And this fact the most sceptical will soon 

 have to admit ; alterations in the object have been detected 

 even with the naked eye. All my own observations and 

 drawings have been made with the one telescope, and without 

 reference to the Cape drawings, how does Mr. Procter account 

 for this ? 



Lieutenant, now Captain Herschel in a letter to Sir J. F. 

 Herschel thinks I must use low powers as I never mention 

 the lemniscate ; this is true, I do use a low power with large 

 field and plenty of light for the drawings ; but I saw the 

 object with the large Melbourne reflector in June 1869, 

 and was unable to detect the lemniscate of the late Sir J. 

 Herschel. At that time the so called lemniscate as seen with 

 my instrument had two openings, one at each end ; shortly 

 after three openings, next four, then five, and now six, as 

 seen in the present drawing. 



In the same letter Captain Herschel enquires, " is it rash 

 to suspect that Mr. Abbott has mistaken the star 77." This 

 question is answered in the notes and queries of the Astronomer 

 Eoyal, for if I had mistaken the star it is clear that Captain 

 Herschel had also mistaken it or the question asked by the 

 Astronomer Royal " has Mr. Abbott copied Lieutenant 

 Herschel's drawing of 1868 ?" would net apply. It was from 

 nightly watching the reduction of this star that the rapid 

 fluctuations in the nebula were observed. 



Mr. La Sueur discovered great changes in the nebula on 

 first applying the large Melbourne reflector to the object, and 

 comparing it with Sir John Herschel's Cape drawing ; and in 

 following up his observations during his stay at the Obser- 

 vatory has left certain drawings, finished and unfinished, 



