258 Floatage of small heavif Bodies in Air. 



to exhibit, by their refractions through the drops, the iris of 

 forty-five degrees, with its coloured mock-suns, and by reflec- 

 tions at the surfaces of the drops arranged in longitudinal 

 strise, the white almicantars with white suns in them so rarely 

 seen. By a small portion of unguent spread over the surface of 

 a looking-glass, and disposed into various striae of various 

 directions by rubbing, strong resemblances of these white 

 atmospheric lines extended to considerable lengths, and va- 

 riously crossing each other, may be exhibited by the reflected 

 light of a candle. If, therefore, this whole course of reasoning 

 can be maintained, the whole theory of these atmospheric 

 phronomena may be considered as established, by referring 

 their formation from the number and parallelism of certain rays 

 to the principles of formation of images by radiants, and from 

 icy machinery of doubtful existence and application to globules 

 of water, to floating globules, dependent for their floatage and 

 diminished refractive power on the same cause, and to falling 

 drops of fully-restored refractive powers. 



I offer, not without due consideration, this explanation 

 of these phainomena, certainly better, and better founded 

 in its principles than all which have preceded, than the 

 prismatic stars of ice of Des Cartes, and tlie snowy ker- 

 nels and cylinders of Huygens, and certainly more consist- 

 ent with circumstances, and the general order of things. I see 

 distinctly in the globule or globular circle, the elements of the 

 iris. 1 observe dimensions in the iris which require a refractive 

 power in the drops different from that of water, in other its 

 usual states of aggregation. I establish from other phaenoraena 

 an adequate change of refractive power in the drops of the 

 •vapour ; and to him who would reject these facts and their con- 

 sequences, I would offer the propositions themselves and the 

 conclusion, in the simple form of queries, after the example of 

 Newton. They may, at least, be fairly enumerated conjcc- 

 turally among observations on the causes and phajnomena of 

 the floatage of small heavy bodies iu the atmosphere. 



