436 Miscellaneous Intelligence. 



winds — one from the southwest, the other from the northwest. The 

 continuation of the investigation will be submitted at future meetings of 



the Association. 



In connexion with this, the author observed that a most important 

 point appeared to be developing itself by means of these observations. 

 Those from the northwest appeared strongly to indicate that some- 

 where in that direction the origin of the great barometric disturbances 

 (a centre of oscillation) giving rise to the waves that pass onwards to- 

 wards the southeast is to be sought. We have already obtained the 



h 



e 



nodal point of the two great systems of European barometric undula 

 tions — namely, Brussels. Between the Orkneys, which appear to be 

 the nearest station to the northwest centre of oscillation, and Brussels 

 the greatest decrease of oscillation occurs. This line of the greatest 

 diminution of oscillation appears to be well determined. 



The author closed his report with an allusion to the American system 

 of atmospheric waves, especially those that accompanied the great Cuba 

 hurricane of October, 1844, which has formed the subject of an elabo- 

 rate investigation by Mr. W. C. Redfield, of New York; and was of 

 opinion that the revolving storm, so ably brought to light by Mr. Red- 

 field's labors, was produced by the crossing of two large long waves 

 moving in different directions, as suggested by Sir John Herschel in his 

 " Report on Meteorological Reductions," presented to the Association 

 in 1843, 



8. On the height of Auroral Arches; by Prof. T. Chevallier, 

 (Proc. Brit. Assoc., 1847, Athen., No. 1029.)— Of all the phenomena of 

 the Aurora Borealis, the arches which are occasionally seen nearly at 

 right angles to the magnetic meridian are the most definite and perma- 

 nent ; and seem to offer the most promising means of ascertaining the 



ight of the region in which that modification of the aurora is formed. 

 In the 118th No. of the " Philosophical Transactions," Dr. Dalton has 

 collected several facts on the subject; and arrives at the conclusion tna 

 these arches are about 100 miles high. Having computed the height o 

 three such arches, I am desirous of laying the results briefly before t e 

 Association. The first was the aurora of March 22, 1841, observed at 

 Dunse, near Berwick, by Mr. Wm. Stevenson ; at Durham, by ™y sel * ' 

 at Belfast, by Prof. Stevelly ; and at York, by Mr. Phillips. The ob- 

 servations over more than an hour, from 8 h 56 m Greenwich mean tun ^ 

 to 10 h ; and the position of the arch was definitely fixed by its plac 

 among the fixed stars. The direction of the arch was ™*£ n * ic * s .l 

 east and west. Its height was computed separately from the o & se t 

 tions at York and Durham, York and Belfast, and Belfast and Durban" , 

 the resulting altitudes being 156, 157, and 165 miles. The second a 

 roral arch was observed on Sept. 21, 1847, at Esk, near D urham ' f( J 

 myself, and at Norwich by Mr. W. Marshall. It was visible W {m 

 about five minutes. The resulting height is 106 miles. This de e^^ 

 nation depends upon two observations only. The third auro 

 was seen on the 19th of March, 1847. It was observed at • Da Y in ° 0x ! 

 at Spalding in Lincolnshire, at Cambridge, at Norwich, in L ° nd0 "| daei 

 ford and Amsterdam. The observations of Darlington and Lan £ ° f 

 from a base of 172 miles, give an altitude of 175-9 m,les; !f " ^ f 

 Spalding and Cambridge, from a base of 114 miles, give an aim 



