TWO INTERSECTING EAINBOWS. Tj> 



This arch did not exceed 7** or 8° in length ; it was of the't W;^s a inort 

 fame breadth with the principal bow ; it had the colours in the ^° '°"* 

 fame order, and nearly of the Hime brightnefs; or if any differ- 

 ence was difcernible, it was, that the tranfition from one co- 

 lour to another was not made with fo much delicacy in the laft- 

 mentioned rainbow as in the former. 



We recollcfled that a phenomenon fimilar to this is defcrl- a""! was appa- 

 bed in the Philofophical Tranfudlions, as having been feen at j,,, ^.j^jg^l^^^ ^|. 

 Spithead, and that it is afcribed by the gentleman who obferved the fua'srays 

 It to the reflection of the fun's rays from the furface of the fea, 

 fo as to fall on the cloud where the rainbow was formed. This 

 hypothefis feemed to agree exad^ly with the phenomenon now 

 before us. 



The accidental rainbow, for fo it may be called, was feen from the fmooth 

 only at the extremity where the principal arch rofe from the 

 fea, and where of confequence, the fun^s rays, reflected from 

 the furface of the water, at that moment very fmooth, might 

 fell on the drops of rain. The other parts of the cloud could 

 not receive rays fo refle6led, as the land intervened, and 

 there, accordingly, no veftige of the accidental rainbow was 

 obferved. 



The accidental rainbow lay, as was already faid, on the Its center was 

 fide toward the fun, and this Is agreeable to the hypothefis ; f°^^ ^^^ ^''"- 

 for the rays that after reflexion from the furface of the water 

 fell on the drops of rain, muft have come as from a point 

 as much deprelTed below the horizon, as the fun was at that 

 inftant elevated above it. The axis of the accidental rain- 

 bow mud therefore have made with the axis of the prin- 

 cipal, an angle equal to twice the fun's elevation, and Its 

 cei^ter muft have jjeen elevated by that fame quantity above 

 the centre of the other, fo that if it had beeii complete, it 

 would have been wholly between the principal rainbow and 

 the fun. 



The only cirumfianpe in which the appearances did not per- tut the interfec- 

 feftly correfpond with this hypothefis, was, that the two rain- ^uiVls'low as 

 bows did not interfecl one another in the horizon, but rather a the horuon. 

 Jittle above It. This however, ought to have no great weight, 

 ?is the refle6led image of the fun cannot have prefented to the 

 floqd a di(k fo regyl^r and well defnied as the fun itfclf and 



the 



