390 Miscellanies. 



tinct and concentrated. At sunrise, the bow coincides with the 

 horizon. 



In the appearance of the evening bow, the whole process of appear- 

 ance and disappearance is in a reverse order : the bow is in the east ; 

 it rises at sunset, and disappears in about half an hour. 



The bow is best seen in the clearest atmosphere, and then an hour 

 before sunrise, a second series of colors forms another bow within 

 the other, and the same height above the horizon, very faint, it is 

 true, and diffuse, but still very perceptible ; so that the series of 

 colors, naming them as they proceed from the centre, and always 

 naming the yellow first, would be yellow, blue, red, yellow, blue, red. 

 I have long observed in examining the various series of prismatic rings 

 that occur in nature, that the order of colors is not the same in the 

 various series. Now in a series of three, we can have but two orders ; 

 either there will be 1,2, 3; 1, 2, 3 ; or 1, 3, 2 ; 1,3,2. In the pris- 

 matic spectrum there are but three primitive colors. Every series of 

 concentric prismatic rings will therefore be one of two orders. The 

 choice of a color to commence with in reading the orders of colors 

 in any series, is indeed arbitrary, the result will always be the same, 

 but as it is necessary to fix upon one, let us fix upon the yellow, and 

 always read from the centre outwards ; this method will fix the order 

 of any series, and the two orders may then very properly be termed 

 the blue order or the red order, according as the blue or the red fol- 

 lows the yellow in reading the series. To illustrate these remarks I 

 would state, that the rings produced by thin plates are of the red. 

 order; the b,alo round the moon is of the hive order; the series 

 round a candle, seen through gauze, is of the red order ; the series 

 on metallic plates, produced by throwing the flame of a blow-pipe 

 perpendicularly upon a plate of metal, is of the Hue order; the 

 rainbow is of the red order ; and in conformity with this arrange- 

 ment, the bow which I have been describing, and which may perhaps 

 with propriety be called the Twilight Bow, is of the blue order. 



Perhaps some of your correspondents can explain this meteoro- 

 logical phenomenon. Your obedient servant, 



Samuel F. B. Morse. 

 New York City University, Dec. 1, 1839. 



Note. — The Twilight Bow has, we believe, been often observed, 

 but we do not know that any description of it is to be found in print. 

 The blue portion of the arch appears to lie within the earth's 

 shadow. — Eds. 



16. Lectures on Phrenology, by George Combe, Esq., of Edin- 

 burgh, in New Haven. — A large audience, embracing a fair propor- 



