1869.] Lieut. HerscheFs Observations of Southern Nebula. 303 



A more detailed account is not now given, as I think I shall be able to 

 modify the method so as to make the outline of these objects more easily 

 visible. 



February 25, 1869. 



Capt. RICHARDS, R.N., Vice-President, in the Chair. 



The following communications* were read : — 



I. " Additional Observations of Southern Nebulae." In a Letter 

 to Professor Stokes, Sec. R.S., by Lieut. J. Herschel, R.E. 

 Communicated by Prof. Stokes. Received January 4, 1869. 



Bangalore, Dec. 1, 1868. 



Dear Sir, — I have the pleasure to subjoin a few additions to my 

 former list of Southern Nebuloe spectroscopically examined. 



The observations extend from the 24th October to the 20th November. 



I will first enumerate those of which no trace of a spectrum of any kind 

 has been detected, and which, I can with confidence state, have no other 

 than a continuous spectrum. I am enabled to do this for the following 

 reason — that even when the jaws of the slit were entirely removed, so as 

 to command a perfectly free field of view (in which stellar spectra were 

 frequently recognized), no light from these objects was visible. That no 

 doubt might remain as to the justice of this conclusion, three faint plane- 

 tary nebulae were looked at in the same way, and were more or less easily 

 recognized as spots of light in the spectroscopic field. It is much to be 

 regretted that I did not long ago make the experiment ; had I done so I 

 should unquestionably have saved myself many tedious hours lost in vain 

 searching. The following may safely be erased from a list of nebulae to be 

 examined for evidence of a " linear" character : — 



Nos. 4/57. "Very bright ; pretty small." 

 27. " Very bright ; very large." 

 67. " Very bright ; large." 

 *162. " Globular cluster ; bright; large." 

 163. " Very bright ; large." 

 339. "Bright; large." 

 *342. "Very bright; pretty large." 

 361. " Very bright ; very large." 

 369. "Bright; pretty large." 

 f544. " Very bright ; very large." 



604. "Very bright; pretty large." 

 f610. "Very bright; large." 



* These were not looked at in the way described above (without a slit), but are 

 nevertheless included, because it is certain they have no visible spectrum. 



t The same remark applies to these ; they were twice examined. 



The brackets denote that the objects are so near each other that one observation 

 sufficed for both. 



