C 59° 1 
Y* *d n sfytempt to explain the Phenomenon 
of the horizontal Moon appearing bigger , 
than when elevated many ‘Degrees above 
the Horizon : Supported by an Experiment. 
By the Rev. J. T. Defaguiliers, LL. 2). 
F.R.S. Communicated Pan. 30, 1734-5. 
HIS apparent Increafeof the Moon's Diameter 
(which a Telefcope with a Micrometer fhews 
to be only apparent) is owing to the following early 
Prejudice, which we have imbib'd from Children. 
When we look at the Sky towards the Zenith, we 
imagine it to be much nearer to us, than when wc 
look at it towards the Horizon ; fo that it does not 
appear Spherical, according to the vertical Seftion 
EFGHI, (Fig. 4.) but Elliptical, according to the 
Seftion eFghi. For this I appeal to every body's 
Senfe of feeing 3 but not to their Reafon, which is 
apt to take off the Prejudice in Perfons that have fome 
Knowledge of Aftronomy. Whereas any other Per- 
fon looking up very high towards the Sky, and then 
forwards near the Horizon, will (when asked) fay 
that the Sky over his Head appears much nearer. The 
Sky thus feen, ftrikes the Eye in the fame Manner as 
the long arch'd Roof of the lie of a Cathedral Church, 
or the Cieling of a long Room. 
This being premifed, let us confider the Eye at C, 
upon the Surface of the Earth, and imagine C at the 
Surface to coincide with K at the Centre j to avoid 
taking into Consideration that the Moon is really far- 
ther 
