Dr Scoresby on the Colours of the DeW'Drop, 61 



these aqueous atmospheric deposits, I w^s led to consider the 

 reason why the Dew-Drop, so striking in its exhibition of re- 

 splendent light and colours, as ofttimes to have called upon 

 the province of poetry to describe its beauties, should so sel- 

 dom present the same richness and variety of tints as are seen 

 in the rainbow ? An attentive observation of the multitudes 

 of diamond-like gems pendant on the grass and sparkling in 

 the morning sunbeam, soon enabled me to discover a not un- 

 frequent coloured drop of yellow or orange ; but in vain, du- 

 ring many favourable mornings, I sought for blue, green, or 

 red. At length it occurred to me that the distance at which 

 many of the most resplendent drops were seen, might render 

 the effect of the colours inappreciable. Availing myself of a 

 14-inch pocket telescope for the determination of the fact, I 

 immediately found that the drop tinged with yellow or orange, 

 as seen by the naked eye, now assumed, according to the po- 

 sition in which it was viewed, the principal variety of the ex- 

 quisite tints of the iris. 



A little practice in investigating this interesting pheno- 

 menon, enabled me (on ani/ occasion of either dew or rain 

 drops being pendant on the grass or shrubs when the sun was 

 tolerably clear) to fix the telescope at once on some of the 

 most fitting globules for exhibiting the colours, and to deve- 

 lope, by a slight motion of the head, whilst viewing a parti- 

 cular globule, the principal tints of the spectrum. 



For the purpose of observation of this beautiful effect of 

 the solar beams, a telescope is necessary which can be ad- 

 justed to a very short focal distance, so that, by being drawn 

 out beyond the usual focus, objects at the distance of only 

 three or four yards may become distinctly visible. With such 

 an instrument coloured dew-drops may be seen in a great va- 

 riety of positions with respect to the sun. For instance, at 

 the angular distances from the sun of about 40°, 45°, 73°, &c. 

 (as measured by the sextant), as also at a variety of angles 

 from the shadow of the head of the observer, from about 5^* 

 to the extent of 60° or upwards. The angular position of the 

 coloured drops, with reference to the sun, indeed, I could not 

 find to be reducible to any given law, from the circumstance, 

 most probably, of the various deviations in the drops themselves 

 fram a true spherical figure. Yet there were obviously /wir- 



