236 Scientijic Notices-^Mhcellaneous* [Sept. 



rays. Now, if Dr. Herschel's opinion were correct, the fimon 

 sitonid begin on the outside of the clotted line, about half-way 

 between r and X, and from this point it should extend inwards 

 towards r and y, and also outwards in the opposite direction. 

 The experiment was repeated many times, but the result was 

 invariably the same. The fusion always began about that part 

 of the spectral image where the yellow or orange rays are placed ; 

 and, on the other hand, when a plate of wax was placed close to 

 the boundary of the red on the outside, where Dr. Herschel says 

 the maximuni, of heat is found, the fusion never commenced at 

 all. The breadth of the luminous ring was about one inch, its 

 diameter three or four inches. 



This experiment, which is extremely simple, and exempted 

 from many sources of error which attach to experiments with 

 the thermometer, seems clearly to show, that the maximum of 

 heat is not beyond the red rays as Herschel supposed, but distinctly 

 on the inside of them, Herschel's doctrine ought, therefore, to 

 be expunged from our scientific treatises : but perhaps it might 

 be no more than a proper mark of respect to the talents of that 

 eminent philosopher, to repeat his experiments, with the view of 

 tracing the circumstances that led him into error. The judicious 

 and accurate Haiiy, in his Elementary Treatise published more 

 than twenty years ago, observes that Herschel's experiments 

 stand in need of repetition (Gregory's Haiiy, ii. 258, 1807); and 

 we learn that when they have been repeated at a more recent 

 period by the French and German philosophers, they have led 

 to different results. 



Prof. Leslie's note descriptive of his experiment will be found 

 in the article Climate, in the Supplement, at the foot of p. 193. 

 — (Scotsman, July 29.) 



2. Luminous Circle around the Moon. 

 On the 26th of Oct. 1825, at about half- 

 past ten in the evening, the following phie- 

 nomenon was observed by two gentlemen 

 at Kensington, — a faint luminous circle 

 surrounding the moon, not sensibly tinged 

 with any colour, and intersected by a larger 

 one parallel to the horizon, passing through 

 tlie moon, and likewise colourless. The 

 circles were not quite continuous in all 

 parts, and there were a few thin clouds : 

 the whole appearance lasted nearly a quar- 

 ter of an liour. Nothing like a paraselene was observed at either 

 of the points of intersection. B. P. 



