to an Astronomical Clock and Telegraph Register. 213 



Fifteen seconds is the ordinary equatorial interval for the wires 

 of a transit instrument, and we have the authority of the greatest 

 of practical astronomers, the lamented Bessel, that five wires, 

 with this interval, are better than seven wires compressed into 

 the same space. 



By using the method of imprinting the dates of the bisections 



of these wires, on the automatic clock register, where the use of 



the ear, and the counting of beats, and the manual labor of writing 



down these dates, are all dispensed with, the equatorial intervals 



may be reduced from fifteen to two seconds, or even to one and 

 a half. 



In this manner the number of bisections in a single culmina- 



tioned. 



ifolcl 



The advantage of the method of imprinting dates of bisections 

 °f wires by a star on the automatic clock register, from those 

 three separate sources of gain, may in round numbers, be estima- 

 ted at tenfold. 



The remarks that follow are based on such an estimate, and 

 are consequently subject to a proportional modification, when the 

 true numerical ratio shall have been determined by experiment. 

 ■According to this estimate then, we are authorized to conclude, 

 that the value of a night's work with a transit instrument, 

 by the printing method, is about ten times as great as by the 



Method now in use among astronomers. 



For moon culminations, which depend upon the comparisons 

 °f transits of the same heavenly bodies, here and in Europe, 

 fifty wires may take the place of seven, and one month's work 

 jnay take the place of a year's work in the manner hitherto per- 

 formed. 



For catalogues of stars, such as were formerly made in Paris 

 and Konigsburg, and are now made at Munich, Bonn, and Wash- 

 ington, where a transit over one wire only, is usually observed in 

 a night, seven transits may now take the place of one, and from 

 the superior facility which the printing method gives of adjusting 

 the transit instrument, the subject of the right ascension of the 

 st ars of such catalogues may now be exhausted for the epoch of 

 the observation. 



!n the case of the ten year catalogues of the right ascension 

 of stars, from the royal observatory at Greenwich, the same labor 

 spent by the astronomer at the transit instrument, by the use of 

 l he printing method, may furnish one of equal precision enry year. 



I am bound to make an exception in favor of the catalogues 

 °f stars furnished by Mr. Rumker from the Hamburg Observa- 

 tory. This indefatigable astronomer, by some process apparently 

 Unknown to his professional brethren, has already doubled the 

 ordinary number of bisections of a star at a single culmination. 



