69 



served more carefully. ]\[r. Abbott's maps were crimped up till I 

 could not read them. I have iiattcned them, and will endeavour to 

 persuade Mr, Dunkin to keep them Hat." 



In the first paper referred to from Lieut. Herschel and Sir 

 W. F. Herschel, page 80, line 21, the former repudiates his 

 own observations as follows : — 



^' You know how difticult it is to represent faithfully one's im- 

 pression of a nebula by a huriiod pencil drawing, and will understand 

 that the accompanying copy (based on all) has no pritension to 

 accuracy. In fact it is a wretched attempt.''^ 



On comparing drawings Nos. 1 and 2 by 'Lieut. Herschel, 

 although both were taken about the same time, it would be 

 extremely difficult to recognise them as applying to the same 

 object. The last two plates, 4 and 5, are by Sir John Herschel, 

 as noted, semi-reversed by being pricked off from his engraving 

 of 1834, or Cape observations. 



Now, if we apply to this mode of procedure the article in 

 the Asironoviical Begister, by G. F. Chambers, on July 7th, 

 1866, it will appear difficult to reconcile its authority : — 

 "Sir John Herschel's Drawings of Nebula. 

 " To the Editor of the Astronomical Register. 



" Sir, — I have lately made a discovery which, whether it be really 

 such or no, at any rate has not, so far as I aui aware, ever been 

 pointed out. All Sir J. HerschcVs draivings of (Husters and JSebidce 

 are represeided as they cannot be seen. The way this has come about 

 appears to be as follows : — The sketch is placed on paper in exactly 

 the position which the object has in tlie (inverting) telescope. This 

 sketch is copied on to the copperplate also exactly as it stands on 

 the paper, and the result is that when the paper is printed the 

 picture is reversed right and left. The inconvenience of this plan is 

 manifest as concerns observers working with the telescope, and 

 seeking to make comparisons between what they see and what Sir 

 John indicates that he saw ; but worse than all this, Lord Rosse 

 and, so far as I have noticed, all other celestial draftsmen, adopt 

 the common-sense plan of making their drawings to show exactly 

 as the telescope shows, conse(piently other sketches placed in juxta- 

 position with Sir J. Herschel's wholly mystify and delude the 

 reader ; indeed I am free to confess that I have myself thus been 

 taken in. More than once have 1 sought in vain to reconcile the 

 engraving of the nebula in Orion, appended to Herschel's Outlines 

 of Astronomy, with the original viewed in an ordinary inverting 

 telescope. Fortunately for me, 1 only copied into my book a 

 limited number of Herschel and Rosse sketches, but in Guillemin's 

 book Sir John's device leads to a far more serious amount of 

 confusion. 



'*Iam, Sir, 



" Sydenham, " Your obedient servant, 



" July 7th, 1866. " G. F. Chambers." 



In some of my early papers I have given an opinion that 



