488 Mr. R. TempletoD on the Augmentation of 



time, the salt cleared out from the bottom, and also from the 

 screen n if any should be found there, as sometimes happens, 

 and the vessel filled afresh for the next experiment. For more 

 accurate investigation the film of brine on the surfaces might be 

 continually renewed by mechanical circulation from the mass of 

 boiling liquid below, and the accumulation of salt might be fre- 

 quently raked off the bottom into a lateral pocket not affected 

 by the lamp, by means of a wire passing through a cork or small 

 stuffing-box or a bit of vulcanized rubber pipe. 



Before going further into this curious subject I should wish 

 to see my simple experiments repeated by abler hands, with such 

 amplification as will naturally suggest itself to the intelligent 

 physicist. My own investigation of the subject has been in a 

 manner guided by a train of reasoning which would be out of 

 place here, pointing to results of wide and varied interest ; but 

 I imagine that the actual phenomena so far described should 

 interest the experimental philosopher, at least as curiosities of 

 physical science. 



Palermo, November 18, 1866. 



LXVII. On the Augmentation of the Disk of the Sun near the 

 Horizon. By Robert Templeton, Esq. 



To the Editors of the Philosophical Magazine and Journal. 



Royal Hibernian Military School, Dublin, 

 Gentlemen, September 28, 1866. 



THE augmentation of magnitude of the sun and moon at the 

 horizon has in all ages attracted the attention of philosophers, 

 and received various conjectural explanations, two of which, 

 ingenious but eminently unsatisfactory, have survived into the 

 present century; but I am aware of none which have not re- 

 ferred the phenomenon to causes extern to the eye of the ob- 

 server, to physical rather than psychological agency. On the 

 last day of February, while walking in the church avenue of 

 this Institution, I noticed the sun rising in fiery splendour be- 

 hind some rather distant trees, and was struck with the distinct- 

 ness with which the branches of these trees, and with which 

 objects in the horizon right and left, were seen — a peculiar state 

 of the atmosphere, always present on these occasions of aug- 

 mented disk, favouring this acuteness of vision. It occurred to 

 me at the moment, that my pupil must be dilated to very distant 

 vision ; and I observed that the light from the sun was so sub- 

 dued as to interfere in no way, whether as regarded its own disk 

 or surrounding objects, with this condition of the iris : it also 

 came to my recollection that, at all times when the phenomenon 



