ON ATMOSPHERIC WAVES. 267 



Report on Atmospheric Waves. By W. R. Birt. 



The British Association, at its last meeting, having entrusted me, under the 

 superintendence of Sir John Herschel, with the further investigation of at- 

 mospheric waves, I immediately entered on the inquiry, and now present the 

 following report of the progress I have made during the past year. It con- 

 sists, first, of the copy of a letter addressed by me to Sir John Herschel, in 

 which is detailed the plan on which I have proposed to examine these in- 

 teresting atmospheric movements, a list of the stations from which I have 

 obtained observations, and the conclusions which I have drawn from a dis- 

 cussion of them ; second, of remarks on the waves and their phases as they 

 passed the several stations ; third, an examination of barometric curves having 

 the spaces between them coloured to exhibit the slope or dip of the atmo- 

 sphere between the stations ; fourth, an explanation of sections of waves in 

 various directions ; and fifth, of additional remarks drawn up after the pre- 

 ceding were finished. 



Cambridge House Academy, Cambridge Road, Bethnal Green, 

 London, August 10th, 1844. 

 Dear Sir, — Since the last meeting of the British Association, I have 

 endeavoured to collect materials for the purpose of determining the extent, 

 direction of motion, and velocity of the atmospheric waves. Several heads of 

 inquiry have suggested themselves to me, such as the progress of large waves 

 similar to that observed by myself in November 1842, an examination of 

 nodal points at Brussels, lines of contemporaneous elevation, or those lines that 

 at any particular period may possess a similarity of pressure, and other sub- 

 jects of a more restricted interest. In order to assist in this inquiry, you 

 most kindly lent me observations made in Russia, Prague, and other parts of 

 Europe. Mr. Airy has most obligingly furnished me with the volume of 

 'Observations made at Greenwich during 1840, 1841,' and I have obtained 

 observations from other localities. Some of the Russian observations I have 

 projected in curves, from which I obtain the same evidence of the progression 

 of the wave as from the discussion of the quarterly observations. I have also 

 projected and compared a few curves at Greenwich and Prague. These at 

 present are too few and the stations too far apart to admit of scarcely any re- 

 sults beyond the motions of the waves ; there are however two periods which 

 promise some very interesting results, — the Equinoctial observations of Sep- 

 tember 1841, from about sixty stations, and the great November wave of 1842. 

 The latter I have paid the greatest attention to, as from its symmetry and the 

 conclusive evidence we have of its motion from Dublin to Munich, it appeared 

 to promise a rich harvest of results. The stations I have obtained observa- 

 tions from during November 1842, are as per accompanying list: — 

 England. Ireland. 



Longstone. Dublin. 



-t?\ i Scotland. 



Haisboro. -^ , 



London. Makerstoun. 



Greenwich. Glasgow. 

 Canterbury. Continental. 



Hastings. Heligoland. 



St. Catherine's Point. Brussels. 



Scilly. Gratz. 



South Bishop. Carlsruhe. 



Bardsey. Munich. 



Birmingham. Prague. 



