CELESTIAL MEASURINGS AND WEIGHINGS. 2IJ 



optician of New York, turning on Sirius a fine telescope 

 of his own construction, noticed extremely near to it a 

 minute star which had eluded all former observation. 

 This may be the body in question. There is even some 

 reason to suppose // is. Its apparent situation is stated 

 to be at least not such as to be incompatible with such 

 a connexion. Its real existence has been verifed, and its 

 apparent distance from Sirius measured, and found to be 

 about seven seconds j corresponding (if seen unfore- 

 shortened) to about forty-seven times the distance of 

 the sun from the earth. 



(40.) Another beautiful specimen of these binary side- 

 real systems is presented by the star No. 70 in Flam- 

 steed's list of those in the constellation Ophiuchus, and 

 therefore cited as 70 Ophiuchi. The ellipse described 

 by the stars of this pair (the one a star of the fourth, the 

 other of the sixth, magnitude) has been determined with 

 much care and every probability of considerable pre- 

 cision. The period of their mutual circulation may be 

 stated at about ninety-six years, and the semiaxis of their 

 mutual ellipse in angular measure at 4"'8. Of this ele- 

 gant couple the parallax has been ascertained by M. 

 Kriiger, from observations made in 1858 and 1859, at 

 o"-i6. And from these data he concludes in the very 

 same way : First, their distance from our own system 

 (1,272,000 semi-diameters of the earth's orbit) ; sec- 

 ondly, the mean distance of the stars from each other 

 (30^ such semi-diameters, so that here also their relative 

 orbit is nearly equal to that of Neptune) ; and, thirdly, 

 the total mass (equivalent to 3 T V times that of the sun). 



