328 Dr. Forster on the dispersive Power 



gentleman, who has shown himself on many occasions active 

 in the cause of science, I am indebted for the opportunity of 

 dissection. 



This specimen is deposited in the Philadelphia Museum 

 under the name of Amphiuma means (Garden). 



[Note. — For Descriptions and Figures of two Species of Siren, see Phi- 

 losophical Magazine, vol. ix. p. 118. — Edit.] 



LV. On the Dispersive Power of the Atmosphere, and on the 

 Peculiarities of Stars. By T. Forster. 



[Concluded from p. 210.] 



TN a late Number of the Philosophical Magazine, you did 

 ■* me the honour to insert some hasty observations on the 

 varieties observed in the refracting and dispersive properties 

 of the atmosphere, and on the nature of the light of several 

 stars. The opinions therein stated are deduced from a num- 

 ber of observations made and continually repeated by me, on 

 the effects of refraction and dispersion. On different occasions, 

 when I made the experiments and drew the natural conclu- 

 sions from them, I was unaware that similar researches had 

 been going forward on the continent, and also in Scotland, 

 which I now learn to be the case ; and I am also informed, 

 that very similar facts to those which I have observed have 

 been discovered by other persons, although, as it appears 

 to me, by the employment of different means. At the time 

 that I was in the southern parts of the continent in 1822, I 

 was totally unaware that at that very time philosophers were 

 investigating the nature and varieties of light and its refrac- 

 tions in the clear atmosphere of the south of Europe. And 

 being at that time engaged in the pursuit of objects more im- 

 mediately connected with meteorology, I neglected to inquire 

 after and to collect information as to what was going on in 

 astroscopical science in the several observatories abroad. 

 But I find that considerable advancement has been made in 

 the knowledge of the peculiarities of the light of stars ; and 

 though I have not at present obtained any published details 

 of the particular observations made, nevertheless have I learnt 

 with pleasure from private individuals, that the results of such 

 observations, made on a most extensive scale, have in a great 

 measure coincided with my own imperfect attempts to illus- 

 trate the singularities of different stars. I am at present un- 

 acquainted with .he different methods adopted by philoso- 

 phers on the continent for separating and examining the se- 

 veral coloured rays. But the method that I have chiefly em- 

 ployed 



