182 • Mr. J. Glaisher's Remarks on the Weather 



The calculation by means of equations (14.) and (15.) does 

 not require a table of natural tangents. It requires the lo- 

 garithmic tables to be opened six times. 



6. For the use of persons who may wish to make the cal- 

 culations without being able to follow the steps of this investi- 

 gation, it may be desirable to give the result separately ; it is 

 this. 



Let ^ be the zenith distance of the shooting star at the mo- 

 ment of disappearance, Z the zenith distance of the point of 

 the heavens diametrically opposite the sun, and ip the distance 

 of this point from the snooting star. Find an angle vp such 

 that 



cotan 4'= cos ^ sec Z cosec (p — cotan <p. 



Then the distance p of the shooting star from the spectator in 

 terms of the earth's semidiameter as the unit is 



p = cos Z cosec <p tan - \I/. 

 ' 2 



, 3 Stone Buildings, Lincoln's-Inn, 

 February 14, 1849. 



XXIII. Remarks on the Weather during the Quarter ending 

 December 31, 1848. Bi/ James Glaisher, Esq., of the 

 Royal Observatory, Greenwich^. 



THE meteorological returns for the past quarter furnished 

 to the Registrar-General have been received from sta- 

 tions spread over the country. The observations have been 

 made, for the most part by experienced observers, upon an 

 uniform plan. The following remarks are based upon obser- 

 vations which have been furnished either to myself or to the 

 Registrar-General, and drawn up to accompany the meteoro- 

 logical tables published by the Registrar- General, all of which 

 have been examined by myself, and reduced under my direc- 

 tion. 



The weather during the period has been variable. 'J'he 

 changes of temperature have beon frequent and great, there 

 has been an unusually large number of exhibitions of the 

 aurora borealis, and the magnetic instruments have been 

 greatly disturbed. The amount of electricity in the atmo- 

 sphere has been small, many days together having passed 

 without the instruments at Greenwich being affected. 



From the 1st of October to the 10th the excess of tempe- 

 rature above the average of seven years was 6°*6 ; the greatest 

 daily excess was 12°*3 on the 7th. Between the 11th and 

 * Communicated by the Author. 



