ASTRONOMY AND METEOROLOGY. 341 



difference of exactly six hours in time, or ninety degrees in space, 

 from the meridian of Greenwich. These round numbers are easy in 

 their use and application. They can be taken from or added to the 

 headings of charts, the readings of chronometers, or the values in the 

 astronomical ephemeris. without delay, and with little danger of mis- 

 take. The selection of the meridian of Washington, which, as the 

 capital of the country, it will first occur to us to select, would be un- 

 suitable, as the difference between it and the meridian of Greenwich 

 is an inconvenient sum to add or subtract. The meridian of New 

 Orleans cuts the great valley of the West, and approaches the central 

 line of our territory on this side of the Rocky Mountains. It has also 

 the practical recommendation, that between the American and English 

 meridians, the degrees and minutes on the chart will be the comple- 

 ments of each other." 



This communication of Mr. Davis was referred by the Association 

 to a committee of mathematical gentlemen, from various parts of the 

 Union, for consideration and report. 



THE LONGITUDE OF BOSTON. 



IT will be noticed, that, in his paper on the American Prime Merid- 

 ian, Lieutenant Davis states that, though the longitude of Boston 

 west from Greenwich is better known than that of any other place 

 on this side of the Atlantic, yet after the lapse of a hundred years, 

 during which observations have been continually going on, there is a 

 probable error of two seconds in the comparative longitude of that 

 place. For some months, however, another means of determining 

 our longitude has been in operation, and it is hoped that, in the course 

 of a year, the longitude of Cambridge, and therefore of any other 

 place in America, west from Greenwich, will be very accurately 

 ascertained. Since the spring of 1849, forty chronometers have been 

 carried to and fro from Greenwich to Cambridge, by every Cunard 

 steamer, and the mean of the variations of the chronometers for each 

 trip being taken, and then the mean for all the trips, it will evidently 

 give the approximate longitude of Cambridge, by giving the difference 

 between the time of the two places, which is easily converted into the 

 difference of longitude. Editors. 



THE PLANET IIYGEA. 



M. GASPARIS, of Naples, who discovered this planet on April 12, 

 1849, has furnished the following elements of its orbit, derived from 

 several observations : 



Epoch, Mav 1, 1849. , 



Mean anomaly, 326 34 22.44 



Longitude of perihelion, .... 242 47 3.44 



node, 285 32 29.72 



Inclination, 3 46 51.27 



Mean daily motion, 590".3784 



This newly discovered planet belongs to the same group with As- 

 trea, Hebe, Iris, Flora, and Metis, all of which are, as will be seen 



29* 



