238 BULLETIN OF THE NATURAL HISTORY SOCIETY. 



weather. In a letter dated July 1st, 1898, Dr. C. Weber, of Bremen, 

 Germany, a distinguished authority on Peat-bogs, gives me an entirely 

 different, and doubtless correct, explanation of the phenomenon which 

 he, illustrates by the accompanying figure (Fig. 4). He shows that it 



Fig. 4. Diagram of rays over a raised peat bog in dark and bright weather. Hochmoor =■ 

 raised bog : B = its highest part. Starker erwarmte Luftschicht = more 

 strongly warmed layer of air. 



is an optical illusion, caused as follows : if in dull weather, the eye of 

 an observer standing near the margin of the bog (i. e., C. in Fig. 4), 

 be at such a height that the top of some object on the opposite margin 

 is just visible, (i. e., A) the ray from one to the other will be straight. 

 If now, the sun appears, the layer of air in contact with the bog will 

 become more strongly warmed than the layers above it, and hence it 

 will become rarified and less refractive. When the ray from the 

 object reaches this layer, it passes into a less dense medium and hence 

 bends from the perpendicular, i. e., away from the surface of the bog 

 (i. e. from b to E). In issuing from this layer, it re-enters the denser 

 layer, and hence it will be bent towards the perpendicular, and there- 

 fore still farther upward from the surface (i. e., from E to F). Con- 

 sequently the ray will pass over the head of the observer (to F), who, 

 finding it necessary to rise vertically some inches to again see the 

 object, naturally thinks the bog itself has risen. 



29. — On the Physiography of the Nictor Lake Region. 



(Read December 5th, 1899). 



At the eastern head of the Tobique River, in the north of the New 

 Brunswick Highlands, lias Nictor, fairest of New Brunswick lakes. 

 It- is absolutely wild, unvisited save by an occasional sportsman or 

 naturalist, and may be reached only by a several-days' canoe journey. 

 It is unsurveyed, wrongly mapped, and scientifically little known. 

 For these reasons, the following observations, made during two visits 



