Januaey 6, 1899.] 



SCIENCE. 



mounted by Lieutenant Goldsborougb in tbe 

 depot of charts and instruments established 

 by him, and was now mounted near the 

 south door of the observatory for the use of 

 the assistants. The sidereal clock was 

 bolted to the western pier of the Troughton 

 transit instrument, but it never performed 

 satisfactorily. 



On assuming command of the United 

 States Exploring Fxpedition, in 1838, 

 Lieutenant Wilkes turned over the di- 

 rection of this observatory to Lieutenant 

 J. M. Gilliss. To perfect and complete the 

 instrumental outfit Gilliss was permitted 

 by the Navy Department to order the fol- 

 lowing instruments : From Parkinson and 

 Frodsham, of London, a sidereal clock and 

 a meantime clock; from Ertel and Son, of 

 Munich, a meridian circle of 4.5 inches' 

 aperture, furnished with circles 30 inches' 

 in diameter, one of which was graduated to 

 three minutes; from William Simms a 

 portable achromatic telescope of 3J inches' 

 aperture and 42 inches' focal length. On 

 the parapet of the Capitol building a 

 south meridian mark was made, which was 

 viewed by reducing the aperture of the 

 transit instrument to 0.9 inch, and at a 

 distance of 2,302 yards a north mark was 

 erected, which could be viewed with the 

 full aperture of the transit instrument. 

 The north mark consisted of an obelisk of 

 sandstone 18 feet high and 14 inches square 

 at the top, having painted on its south face 

 five black lines, three inches apart. 



Up to 1838 the work at the ' Depot of 

 Charts and Instruments ' consisted of such 

 astronomical observations as were needed 

 for the rating of chronometers. In the be- 

 ginning of that year instructions, prepared 

 by Lieutenant Charles Wilkes, were trans- 

 mitted through the Navy Department to 

 Lieutenant Gilliss, directing him to coop- 

 erate with the United States Exploring 

 Expedition during the years 1838 to 1842 

 by systematically observing the following 



named objects : (1) The Moon and moon- 

 culminating stars. (2) Falling stars, par- 

 ticularly the periodic ones in November. 

 (3) All eclipses of the San and Moon. (4) 

 Eclipses of Jupiter's satellites. (.5) Occul- 

 tations of the larger stars. In addition to 

 the work required by these instructions 

 Lieutenant Gilliss determined the right as- 

 censions of 1,248 stars, which were reduced 

 to the epoch January 1, 1840, compared 

 with the right ascensions of the British As- 

 sociation Catalogue and published in 1846 

 in an 8vo. volume of astronomical observa- 

 tions containing xxv-f671 pages. Dur- 

 ing the years 1840 to 1842 Gilliss also 

 made at the ' Depot of Charts and Instru- 

 ments,' a fine series of magnetic observa- 

 tions, which were published in 184.5 in an 

 8vo. volume of xxviii+648 pages. 



The facilities for scientific work at the 

 little observatory on Capitol Hill were very 

 limited, but Gilliss used them most assid- 

 uously. He endeavored by actual achieve- 

 ment to demonstrate to the Navy Depart- 

 ment and to Congress the desirability 

 of providing an observatory especially 

 equipped for executing the most refined 

 astronomical work, and in this he was suc- 

 cessful. On the 15th ot March, 1842, the 

 House Committee on Naval Affairs reported 

 to the House of Kepresentatives a bill ' to 

 authorize the construction of a Depot for 

 Charts and Instruments of the Navy of the 

 United States,' together with a written re- 

 port which stated at some length that the 

 present ' Depot ' and its observatory are in- 

 adequate for the purposes intended, and are 

 unsafe for the protection of the valuable in- 

 struments ; that we are indebted to other 

 nations for the data which enable our ves- 

 sels to cross the ocean ; that an observatory 

 is absolutely essential to the performance of 

 the duties which devolve upon the ' Depot ;' 

 that the existing observatory was erected at 

 private expense, and that facilities should 

 be provided for the execution of magnetic 



