11 



upon tlie illuiiiinaied surface. The diameter of the red ring of the 

 corona was about 18", and lie ascertained, by experiment, that the 

 distance of the plane on which it was formed, was only 70 feet. 

 The red occupied the interior of the prismatic circle. When com- 

 pletely immersed in the cloud, the shadow of the observer assumed 

 a new appearance, owing to the want of a definitely illuminated 

 surface upon which it could be thrown ; and the continuation of 

 the shadow towards the interior of the cloud, presented the aspect 

 of shadows when a sunbeam is admitted into an atmospheric space 

 filled with light dust; and, by the effect of perspective, gave an 

 appearance of a true convergence of rays, such as is occasionally 

 observed on a great scale opposite to the sun. 



The author pointed out that the theory of the coloured rings 

 suggested by Mr Fraunhofer is untenable. It supposes the in- 

 flexion of rays by watery particles round the head of the observer, 

 whilst experience shews, that these effects are produced when the 

 observer stands in a perfectly pure atmosphere, and even at the 

 distance of 1000 feet from the cloud. The theory of Dr Young 

 was also noticed, which presumes a quadruple reflection in the 

 interior of the aqueous drops ; an opinion which, perhaps, it may 

 be difficult to reconcile with the great brilliancy of the colours 

 displayed. 



February 18. 

 Dr hope, Vice-President, in the Chair. 



The following Donations were presented : — 



Transactions of the Society for the Encouragement of Arts, Ma- 

 nufactures, and Commerce. Vol. XLIX. Part I. — From the 

 Society. 



Flora Batava. No. 92. — From His Majesty the King of the 

 Netherlands. 



The Annual Reports of the Leeds Philosophical and Literary 

 Society for 1828, 1829, 1830, and 1831.— From the Society. 



The following conimunications were then read . — 



1. Notice respecting the Application of Heated Air to 

 Blast Furnaces. By Robert Bald, Esq., F.R.S.E. 

 (To be continued.) 



