MATHEMATICS AND NATUEAL PHILOSOPHY. 191 



VARIABLE ST-^ES. 



The object to -which my communication of the 18th had reference con- 

 tinues to occupy the same position in the heavens as on Saturday last, and is, 

 therefore, in all probability, an addition to our list of telescopic variable stars. 



While upon this subject let me point out one or two stars belonging to the 

 same class, which are well worthy the attention of observers. 



The bright star in Canis Minor, Procyon, has a small companion, the discovery 

 of which, I believe, we owe to Admiral Smyth, who observed it in November, 

 1833. I have searched in vain for any previous mention of it, though Procyon 

 has been on the list of standard stars, and consequently under constant observa- 

 tion in meridional instruments, for something over a century. The companion 

 was missed by Professor Bond, of Cambridge, IT. S., in 1848, but was again 

 detected in March, 1850, by Mr. Fletcher, of Tarn Bank, Cumberland, who ascer- 

 tained its position-angle with respect to Procyon. Since this date I am not aware 

 that it has been perceived. I have repeatedly sought for it with Mr. Bishop's 

 telescope of seven inches aperture, during the years 1853-4-5, and have always 

 found its place perfectly blank. The appearance of the companion star, at cer- 

 tain distant intervals, is sufficiently established. This, however, is not the only 

 point of interest about it. Procyon, like many other so-called " fixed" stars, 

 possesses a considerable proper motion, whereby its actual position in the 

 heavens is altered to the amount of 1| second annually. When Admiral Smyth 

 observed the small star in 1833, he estimated its position with regard to Procyon 

 at 5° north of the parallel of declination on tho eastern or following side, and its 

 distance 145 seconds of arc. In 1850 the proper motion of Procyon would have 

 changed the apparent angle of position of the companion (supposing it fixed) bv 

 rather more than 5 P ; but Mr. Fletcher's observation does not agree with this 

 inference. He found by micrometrieal measures that the small star was still 

 about 5|° north of the parallel, as in 1833. His angle reduced to the date of 

 Admiral Smyth's observation would bring the stars exactly on the same parallel 

 of declination, in which position an error to the extent of 5°, even in an estimated 

 angle, is very improbable. There is, consequently, strong reason for concluding 

 that Procyon is carrying this small variable neighbor along with it. How far 

 this circumstance may be supposed to accouut for the irregularities in the move- 

 ment of the bright star, -which led Professor Bessel to suggest the probable exist- 

 ence of a dark body in its vicinity, I will not attempt to discuss. Mr. Schmidt, 

 of Ohniitz, has lately drawn attention to the colored star on the confines of Lepus 

 and Erid.iuus, which I remarked while comet-sweeping in October, 1845. At 

 that time it was of the most intense crimson, resembling a blood-drop on the 

 black ground of the sky. As regards depth of color, no other star visible in these 

 latitudes eor.ld be compared to it. In brightness it was just beyond the unassisted 

 vision of most persons, or between the 6th and 7th magnitudes, and as such I have 

 always seen it between 1845 and 1854. Mr. Schmidt now states that its light is 

 rapidly on the increase, while the intensity of color appears to be fading. Change 

 of color in the variable stars as they go through their periodic fluctuations is a 

 fact confirrae I by our observations on Borne of these objects during the past few 

 years, though I am not aware of .-my distinct reference to it in astronomical 

 works, I will here adduce one or two instances: — 



1. Near the star numbered 77, at the extremity of the South wing of Virgo, if. 



