CONTENTS. 



part I. 



THE CENTENNIAL CELEBRATION OF THE ACADEMY, May 26, 1880 . . 1 



part n. 



I. The Tortugas and Florida Reefs. By Alexander Agassiz 107 



II. The Apparent Position op the Zodiacal Light. B^- Arthur Skarle . 135 



III. On the Square Bar Micrometer. By S. C. Chandler, Jr 158 



IV. Stellar Photography. By Ed\yai:d C. Pickering 179 



V. A Catalogue of 130 Polar Stars for the Epoch of 1875.0, resulting from 



ALL the AvAILARLE OBSERVATIONS MADE r.ET\VEEN 1860 AND 1885, AND 

 REDUCED TO THE SySTEM OF THE CATALOGUE OF PUBLICATION XIV. OF 



the Astronomiscme Gesellschaft. By WiLLiAji A. Rogers and Anna 

 WlNLOCK .... 227 



VI. Pritchard's Wedge Photometer. By S. P. Langley, C. A. Young, and 



E. C. Pickering 301 



VII. Memoir of Daniel Treadwell. By Morrill Wyman 325 



