ON THE EQUATORIAL TELESCOPE, 
340 
chase such an instrument, but would not order one without the 
improvements now described, nor incur the expence of one 
on a larger scale. 
Enumeration The advantages of a small equatorial, with the improve- 
ot the mime- ° t > r 
rous and ex- tnents now suggested, are — It serves as an universal angular 
ta"e!Tof^the”' ^ll the purposes of common trigonometrical 
instrument so surveys and measurements, — It forms a portable observatory for 
improved. ascertaining, within a small degree of the truth, the right as- 
censions, declinations, and other relative positions of the hea- 
venly bodies, and for viewing their various phenomena. — It 
serves as an universal sun-dial, from which, by a single obser- 
vation, and without any calculation, the true time may be found 
to 30 or even 13 seconds: and therefore forms an excellent 
regulator for adjusting the public clocks of any town or village. 
Ey this instrument the position of the meridian may be found 
from only one observation, and the telescope directed to point 
at any planet or star, however distant from the meridian, 
either by day or by night ; an object which cannot be effected 
by any other instrument. It will, of course, serve for detect- 
ing the planetary bodies, and most of the stars of the first and 
second magnitudes, in the day-time. Being furnished with 
astronomical powers, it serves for viewing the lunar mountains 
and cavities, the solar spots, the belts and satellites of Jupiter, 
the phases of Venus, the ring of Saturn, and other celestial 
phenomena ; and therefore supersedes, in a great measure, 
the use of any other astronomical telescope. It has also this 
peculiar advantage above a cqmmon telescope, that there is no 
occasion to alter the vertical direction of the telescope, in 
order to keep the object in the field of view, the apparent diur- 
nal motion of the heavenly bodies being easily followed by the 
simple application of the hand to a screw, which enables us 
to view them, for a length of time, with greater steadiness 
and ease. It is often difficult, when a high power is used, to 
point a common telescope to an object in the heavens. This 
difficulty is avoided in the equatorial, by adjusting the telescope 
to the declination of the body, and when the equatorial motion 
is 
