2l6 



1'ilILOSOl'HlCAL. TRANSACTIONS. 



[ANNO 1/82. 



that one of then) again is double. The first, or single 

 star, is the largest ; the other two are both smaller, 

 and almost equal, but the preceding of them is rather 

 larger than the following. They are all w. The two 

 nearest with 227, 1 diameter of the preceding, or 

 nearly ij of the following; with +(>(>, 1 ' diameter of 

 the preceding. Position of the two nearest 1 1° 32' s 

 following. For an account of the single star, see the 

 2d class. As perfect as I have seen this treble star with 

 460, it is one of the most beautiful sights in the hea- 

 vens ; but requires a very fine evening. 



11. In constellatione Cancri, Fl. II. 



Mar. 13. — Double. Considerably unequal. Both 

 pale r. With 227, 1 full diameter of L; with 4n'0, 

 about If diameter of L. Position 86° 10' n preceding. 



12. d Serpentis, Fl. 5.9. In Cauda. 



July 17. —Double. Very unequal. I, reddish w; 

 S fine blue. With 227, 1 full diameter of L; with 

 278, I i diameter of L. Position 44° 33' n preceding. 



13. In constellatione Aquilae, near Fl. 37- 



July 25. — A curious treble star. It is the last star 

 of a telescopic trifolium n following k, similar to that 

 in the hand of Aquarius. The two nearest very une- 

 qual; the 3d star excessively small, and not visible 

 with 227- Tile two nearest with 460, no more than ', 

 diameter of L; the farthest about 7 or S". 



14. In constellatione Aquilae, Fl. 24. 



July 30. — Double. In Harris's maps it is the star 

 in the elbow of Antinous. Excessively unequal ; the 

 small star is but just visible with 2J7 ; but with 400 

 it is pretty strong. L pale r; S d. With 2-7, 1 full 

 diameter of L; with 460, \\ diameter of L. Posi- 

 tion 72° (>' s following. 



15. i Bootis, Fl 4 4. 



Aug. 17. — Double. In Harris's maps it is marked 

 i, but has no letter in Fl. Atlas. Considerably unequal. 

 Both w. Witli t'l7 they seem almost to touch, or at 

 most I diameter of S asunder; with 4d'0, | or J dia- 

 meter of S. This is a fine object to try a telescope, 

 and a miniature of « Geminorum. Position 29° 54' n 

 following. 



16". 1 Coronae borealis, Fl. 2. 



Sept. p. — Double. A little unequal. They are 

 whitish stars. They seem in contact with 227, and 

 though 1 can see them with this power, I should cer- 

 tainly not have discovered them with it; with 460, 

 less than | diameter; with 932, fairly separated, and 

 the interval a little larger than with 400. I saw them 

 also with 2010, but they are so close that this power is 

 too much for diem, at least when the altitude of the 

 stars is not very considerable; with 460 they are as 

 fine a miniature of i Bootis as that is, of « Geminorum. 

 Position 59° 19' n following. 



17. In constellatione Bootis, near Fl. 51. 



Sept. 10. — Double. It is a star near «- not marked 

 in Flamsteed's catalogue. Considerably unequal. Both 

 dusky w inclined to r. The interval with 460 is | 

 diameter of S. The position of die small star is turned 

 towards y< a little following the line which joins L to 

 fij Bootis. See </• Bootis in the 6th cl iss. 



18, In constellatione Coronae borealis. 



Sept. 10. — Double. It is the smallest of 2 tele- 



scopic stars between 6 and S~, not contained in Fl cat. 

 Equal. Both d. With 460, about Ig diameters. Posi- 

 tion 21° 0' n following. 



19. /; Draconis, near Fl. 20. 



Sept. 1 0. — One of the most minute of all the double 

 stars I have hitherto found. It is the small telescopic 

 star near the preceding /; Draconis. Considerably un- 

 equal. Both dusky w inclining to r. With 460, they 

 seem in contact; I ha\ r e however had a very good 

 view of a small dark division between them. Position 

 (by exact estimation) 25 or 30° s preceding. They 

 are too minute for any micrometer I have. It is in vain 

 to look for them if every circumstance is not favourable. 

 The observer as well as the instrument must have been 

 long enough out in the open air to acquire the same 

 temperature. In very cold weather, an hour at least 

 will be required; but in a moderate temperature, half 

 an hour will be sufficient. 



20. In dextro humero Orionis, Fl. 52. 



Oct. 1 — Double. A little unequal. Both w a little 

 inclining to pale r. With 227, I diameter; with 460, 

 h diameter. Position 6"9° 41' s preceding. 



21. c Trianguli, near Fl 12 and 13. 



Oct. 8. — Double. It is the most north of a small 

 telescopic trapezium of unequal stars. Extremely un- 

 equal. With 460, I diameter of L. Position (by 

 estimation) 55 or 6'o° n preceding. 



22. » Orionis, Fl. 33. Duarum praecedentium 13 im 

 (*>) antecedens. 



Oct. 22. — Double. Considerably unequal. Lw: 

 S w ; inclining to blue. With 227, they seem almost 

 in contact; with 46'0, ^ diameter of S. Position 6" 1° 

 23' n following. A very pleasing object and easily 

 seen. 



23. In posterioribus femoribus Canis minoris. 

 Nov. 21. — A most minute double star. It is the 



small telescopic star following Procyon. A little un- 

 equal. Both w. With 278, £ of a diameter of S; 

 with 46"0, near | of a diameter of S. They are closer 

 than n Coronae, because their diameters, by which 

 they are estimated, are smaller. Position 27°21's 

 following. To see this very minute double star well, 

 Procyon should be near its meridian altitude. There 

 is a small telescopic star preceding the double star. 

 Distance 1' 59" 39 from centre to centre. 



2). £ Cancri, Fl. 16". 



Nov. 21. — A most minute treble star. It will at 

 first sight appear as only a double star, but with proper 

 attention, and under favourable circumstances, the pre- 

 ceding of them will be found to consist of 2 stars, 

 which are considerably unequal. The largest of these 

 is larger than the single star; and the least of the 2 is 

 less than the single star. The 1st and .'d (in the order 

 of magnitude) pretty unequal. The 2d and 3d pretty 

 unequal. The 2 nearest both pale r or r. With 278, 

 but just separated ; with 46'0, j diameter of S. Po- 

 sition 80° 32' n following. For measures relating to 

 the 3d or single star, see £ Cancri in the d class of 

 double stars. 



Second Class <>t Double Sims. 



I. t « Geminorum. Fl. 66. In capite praece- 

 dentis IP. 



