ON THE EQUATORIAL TELESCOPE, 
345 
was sure it was pointed directly to the star. That the darkness 
of the ground on which a star is seen, is not, of itself, sufficient 
to account for the effect produced by magnifying power, ap- 
pears from the following circumstance, viz. that by diminishing 
the aperture of the object-gla.ss, we may produce as dark 
a ground as we please, but this contraction of aperture will Observation, 
not serve to render a star visible, if a small power be applied : b 
1 nay, the diminution of the aperture beyond a certain limit, pre- iiavc the dcu- 
vents a star from being easily seen, which would otherwise be 
iquiteperceptible. I am, therefore, induced to conclude, that v.l,at cnifiing 
•some additional reasons must be assigned why iP^gnifying 
I power produces this effect. To ascertain these rea.ons is the 
po\\i r,.>o long 
object of tins query. a.« the apt r- 
For similar reasons 1 should wish to be informed if the fact exceeds 
tllC pupil III 
I is established beyond a// don/'/, that the stars are visible in thetlntoriiKrcai- 
I day time from a deep well or pit, or from the bottom of a appca'l'^suf- 
I high tower. This fact has been asserted by many respectable ira>on 
... 1 , j . 11 1 r "*'y “ pl'.' '*'* 
writers, both ancient and modern, and IS so generally taken lor cal point (or 
granted, that reasons have been assigned to account for the , 
° ■=* facc'slioiibl 
I effect; but none of those wliose works I have seen, who be nioic \iu- 
i allude to the fact, ever .assert that they themselves, or any 
I their literary friends, have witnessed this phenomenon. Have i,c really 
.any of* your numerous scientific readers or correspondents seen 
I the stars in the day-time from a deep pit? Are miuers, col- wells, ac. 
liers, and subterraneous surveyors, who have opportunities of 
making such observations, known to have Irequently observed 
them? If so, arc smrdl stars distinguishable in such a situ- 
ation ? Or, is it only when a star of the first magnitude hap- 
pens to pass near the zenith that such a phenomenon is ob- 
sefved ? If the fact is unquestionable, the stars should, in my 
opinion, for a similar reason, be seen when we look up through 
a long strait chimney staik, or through a long tube, where the 
rays of light are prevented from striking on the inside by the 
interposition of proper apertures. < Is it a f.ict, as has been 
.asserted, that Tycho Bvahe,-the Danisti astronomer, frequently- 
set in a deep pit and contcmpl.ited the stars in tlie day time as 
reflected from a mirror which was placed before him ? 
An 
