Knonledi/e. 



THE CLUSTER IN HERCULES (MESSIER 13). 

 Enlarged from a Photograph taken by ilr. W. E. Wilson, of Daroniona, Co. Westmeath, Ireland, with a silver-on-glass vellector 

 by Sir H. G-RrEB, of twenty-fonr inches aperture, and ten feet six inches focal length. Photograph taken August oth. lS9t. 

 Exposure, one Iiour. 



