mis IN THE DEW. ]^g 



XIV. 



An Iris seen in the Dew, and a Liaiar Iris. Bij a Corre^ 

 spondent. 



j.j^ To Mr. NICHOLSON. 



VJ'NE sunny morning lately, as I was riding across a A;>pareiulv 

 meadow, the sun being on my left, I perceived, to my right rectilinear irij 

 hand, upon the grass, a beautiful straight line of prismatic ^^ ^ ^^' 

 colours, formed by the refraction and reflection of the solar 

 rays by the dew drops. The line extended from me all 

 across the meadow, aud formed with the shadow of a verti- 

 cal object an angle of about 45°. 



What shall we call this phenomenon? not a rainbow; for 

 it is neither a bow, nor produced by rain : the French name, 

 aro-en-ciel, is equally inapplicable ; and so is the Italian, 

 Varco baleno, Varco celeste. 



A few weeks since, about nine o'clock in the evening, Lunar iris, 

 the weather being very frosty, I saw a beautiful circle, or 

 iris, round the moon, exhibiting all the prismatic colours 

 -distinctly, whenever a thin fleecy cloud intervened. Per- 

 haps these phenomena may be sufficiently rare^ to merit 

 being recorded in your celebrated Journal. 

 I am, Sir, 



Dec. 14, I8O9. Your obliged reader, A. M. 



ANNOTATION. 



The rainbow on the ground was observed at the beginning 

 of the last century, by Mr. Langwith, Phil. Trans. No. 

 269; and B. Martin, in his Grammar, p. 213, correctly 

 observes, that its tigure will be an hyperbola, parabola, or 

 ellipsis, according to the Sun's height. A. M, must have 

 seen one of the legs of a curve of one of these descrip- 

 tions. N. 



S(. Thomas's and Giii/''s Hospitals. 

 The Spring Course of Lectures at these adjoining Hospi- 

 tals will commence the beginning of February. — For the 

 particulars see our Journal, vol. XIV, p. 7- 



To Correspondevis. 

 As T cannot give a satisfactory answer to A. B., without a 

 figure or two^ I am under the necessity of deferring it till 

 next month. — The papers of Mr. l^arlow, Mr. Brewerton, 

 Mr. Sheldrake, Mr, Ellis, and G.O., shul! be given in our 

 n£xt. 



