New Experiments on the Solar Spectrum. 137 



Dr. Mantell has written his work under the pressure of se- 

 vere infirmity, and it is a noble example of the superiority of 

 the mind to the sufferings of the body. If there is less of flow- 

 ing and captivating eloquence in the "Medals of Creation" than 

 in the " Wonders of Geology," it is because the plan requires 

 the most rigid accuracy, and the utmost technical precision ; still 

 we find in his introductions and retrospects the same captivating 

 diction, and the same lucid philosophy, which have delighted 

 the readers of the Wonders, and the four uniform volumes may 

 well go forth in company, as they form a harmonious unity, re- 

 plete with instruction and entertainment. 



Senior Editor. 

 November 27, 1844. 



Art. XII. — New Experiments on the Solar Spectrum; commu- 

 nicated by Professor Olmsted. 



Some months since I was invited by my friend, Mr. Forrest 

 Shepherd, of this city, to witness some experiments which he 

 had devised on colors. I was not only much delighted with the 

 singularly beautiful and diversified figures and colors which he 

 produced from the solar spectrum, but also surprised by their 

 novelty, since I had never either heard or read of any similar 

 experiments. 



Mr. Shepherd had been led to make some researches upon 

 colors in consequence of having witnessed, in the year 1826, 

 upon a peak of the White Mountains, that beautiful phenomenon 

 called the "apotheosis of travellers," in which the shadow of the 

 spectator, thrown by the sun on a stratum of clouds below him, 

 is seen with the head encircled by a splendid coronet of rain- 

 bows.* This gorgeous spectacle has been enjoyed and describ- 

 ed by a few other travellers who have ascended high mountains, 

 as Bouguer, Saussure, and especially by Ramond, who saw it in 

 great perfection on the summit of the Pic Du Midi.f 



With the view of repeating and varying Mr. Shepherd's ex- 

 periments, I availed myself of a small dark chamber fitted up 



* Amer. Journal of Science, Vol. xii, p. 172. 



i London Quart. Jour. Science, Literature and Arts, 1827. Malte Brun's Ge- 

 ography, Vol. I. 

 Vol. xLviii, No. 1.— Oct.-Dec. 1844. 18 



