1839.] Description of an Astronomical Instrument. 835 



myself able to determine heights and distances with it with very great 

 exactness. 



Let us now turn our attention to the reverse side, where, by remov- 

 ing the revolving indices, we meet with numerous letters arranged 

 around the centre in concentric zones, being an arrangement called 

 lotas, the Indian metaphor of beauty, and a form peculiarly favoured 

 of Indian sages. 



The numbers 1, 2, 3, 4, it will be observed, are written exterior 

 to the outer circle, and indicate the beginning of the four slokes 

 which make up the figure ; the three first being read across, and consti- 

 tuting diameters to the outer circle, the fourth forming the outer 

 circle itself. The following is a translation. 



' The length of the shadow of the gnomon at Khota is five ungols 

 * and 30 beaugols, in consequence of which the elevation of the signs 

 'above the horizon takes place there in times the particulars of which 

 ' are as follow—- 



Aries, 



3 r 



)unda 



s, 43 



Taurus, 



4 



)> 



15 



Gemini, 



5 



>) 



5 



Cancer, 



5 



j) 



41 



Leo, 



5 



}) 



43 



Virgo, 



5 



>? 



33 



s But the other six signs, namely Libra, Scorpio, Sagittarius, Capri- 

 * cornus, Aquarius, and Pisces, are in point of rising above the horizon 

 e equal to the former six, when taken in inverse order ; that is to say, 

 ' Libra rises in the same time as Virgo, and so on/ 



The length of the shadow here given is not quite correct,* at least 

 if I may credit, which I have good reason to do, the result of Mr. 

 Hunter's computations, published in the fourth volume of the Asiatic 

 Researches. According to that careful observer, the latitude of Khota 

 is 25° 11' 41", while the datum of the instrument gives but 24° 37' 25", 

 which, notwithstanding some corrections which I shall presently make, 

 still leaves the latter in defect. 



The difference between the latitude of Khota, as calculated by 

 Mr. Hunter, and that deduced from the Indian datum is, 34' 16"; 

 this is considerable, and is perhaps not entirely attributable to im- 

 perfection of instruments or carelessness of observation, but to the 



* The same length of shadow 5 a 30 b is the same as that supposed in the Bhagul- 

 pore tables given by Le Gentil. In both cases the number is suspiciously round, and 

 in both also somewhat inaccurate. 



