S64 Report of the Regents of the University, 



when it passes the meridian : from this deduct 5 hours and 54 mi- 

 •nutes, which will give the time required, when the azimuth is east ; 

 •but when it is west, the 5 hours and 54 minutes must be added to 

 ihe time of the transit. This is a medium for our State, and although 

 it will vary with the latitude, it will not differ one minute from the 

 'truth, between the extremes of our northern and southern bounds. 



It is recommended to every college and academy to provide itself 

 annually with a Nautical Almanac, in order to enable its students to 

 exercise themselves in lessons of practical astronomy, and, among 

 'bthers, such as those of which this circular gives specimens. 



In order to make the observations as correct as possible, a good 

 transit instrument is required, and the observations should be seve- 

 ral times repeated. Astronomers never trust to a single observation, 

 for it may be, and often is affected by the peculiar state of the at- 

 mosphere, but they make a number in succession, and take the mean 

 •of them, rejecting those which differ much from the others. 



The instrument should be directed to the star some time before 

 it has made its greatest apparent departure to the east or west, and 

 follow it until it becomes stationary ; then bring the telescope of the 

 instrument to a horizontal position and mark the place to which it 

 .points, at a considerable distance from it. Let this be as far as the 

 evenness of the ground will admit ; then measure the distance be- 

 tween the instrument and the mark so made : the offset from which 

 to the meridian is thus found, by plane trigonometry : 



As radius is to the distance between the instrument and the mark, 

 so is the tangent of the azimuth, as before calculated, to the offset to 

 be made west, when the azimuth is east, at right angles from the line 

 of observation ; then a line drawn from the place of the instrument, 

 through the termination of the offset, will be the true meridian, on 

 which, at a convenient distance from each other, stable and perma- 

 nent monuments ought to be placed ; such as stones sunk deep into 

 the ground, and having on their faces lines drawn to show with pre- 

 cision the course of the meridian. 



Where no transit instrument is possessed or can be procured ; as 

 the means of an approximation to a true result, a plumb line may 

 be used, and by it the observations conducted in the manner now 

 prescribed. In such case the upper end of the line should have as 

 high a fixture as can be conveniently obtained, and to its lower end 

 should be fastened a heavy weight, immersed in a vessel of water to 

 steady it. A light will be required to illuminate the plumb line to 



