﻿400 Intelligence and Miscellaneous Articles. 



methyl-morphium, &c. Indeed it may be stated generally that, as 

 far as observation goes, compounds of trebly related nitrogen exert 

 an action totally different in kind from similar compounds of five- 

 fold-related nitrogen, that a similar difference exists between the 

 triatomic and pentatomic compounds of other members of the nitro- 

 gen family, and that this principle appears to be of still wider, and 

 probably general application. 



The speaker, in conclusion, drew attention to the peculiar interest 

 attaching to those regions of science which lie on the frontiers be- 

 tween two distinct departments, as on their successful exploration 

 would depend the ultimate fusion of all physical sciences into one, 

 the science of dynamics, the science which treats of matter and 

 energy and their relations to one another. Such a fusion is pro- 

 bably very remote ; but we now see in the border-land between 

 chemistry and physics that slow process of absorption going on 

 which has already converted the once independent sciences of sound, 

 light, heat, electricity, and magnetism into more or less completely 

 subjugated provinces of the great empire of applied mathematics. 

 If we believe in the unity of the plan of creation, we must believe 

 that this process will advance and ultimately triumph. 



LVII. Intelligence and Miscellaneous Articles. 



ON A MIRAGE IN THE ENGLISH CHANNEL. 

 BY JOHN PARNELL, M.A., F.R.A.S.* 



HAVING had the good fortune to witness an extraordinary mirage 

 at Folkestone on the 13th of April in the present year, I ven- 

 ture to think that the following description of the phenomenon, so 

 far as it passed under my observation, may not be uninteresting. 



During the morning, and up to 2 o'clock p.m., a dense fog had 

 hung over the sea ; but apparently it was not very deep, as the sun's 

 rays penetrated it pretty freely. At the hour above mentioned the 

 fog opened towards the S.E., disclosing the cliffs on the French 

 coast ; and in the course of a few minutes the fog had disappeared, 

 leaving the atmosphere in a state of unusual transparency. The 

 French cliffs were apparently so lofty and with every indentation so 

 clearly visible, that one might easily have imagined that they were 

 but ten miles distant. On examining the objects in view through 

 a small telescope with a 25-power, it was at once apparent that this 

 arose from something more than common looming. The French 

 coast could be seen from near Calais towards the E. to far away and 

 many miles beyond Boulogne towards the S.W., the land in the 

 latter direction being ordinarily invisible, as it is situated below the 

 horizon. Immediately under the erect image of the coast was an 

 inverted one, of about double the height of the former. The light- 

 house at Cape Gris Nez gave five images in a vertical line ; — the 

 lowest erect but somewhat magnified ; above that and separated 

 from it a pair of images of the centre and highest portion of the 

 building only, one erect and the other inverted ; and over these an- 

 other pair, the inverted image being like the former one, but the 

 * Communicated by the Author. 



