<5) PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OP LONDON. FOR THE YEAR MDCCCXXVI. PART I. Printed at the Expence of the Board of Longitude. M LONDON: PRINTED BY W. NICOL, SUCCESSOR TO W. BULMEE AND CO. CLEVELAND- ROW, ST. JAMEs's; AND SOLD BY G. AND W. NICOL, PALL-MALL, PRINTERS TO THE EOYAL SOCIETY, MDCCCXXVI. ri7i-7> Q 41 L8 ftl-Z. PHILOSOPHICAL TRANSACTIONS. Observations of the apparent distances and positions of 4f5^ double and triple Stars, made in the years 1823, 1824, and 1825; together with a re-examination of 36 Stars of the same descrip- tion, the distances and positions of which were communicated in a former Memoir. By James South, Esq. F. R, S, Read November 17, 1825. J. H E Royal Society having honoured the observations of 380 double and triple stars made by Mr. Herschel and myself with a place in the Philosophical Transactions, I am induced to offer for the like distinction a fresh series. The Equatorial Instruments and Micrometers used on the present occasion, being precisely the same as those with which the preceding observations were made, the prefatory matter attached to the former communication, will be gene- rally applicable to this. As however some of the results have been obtained in England, and others in France, the place where each series of measures was procured, accompanies the date and instru- ment of observation. From the 3rd of April, 1825, to the demolition of the Observatory at Passy, the micrometer of the Five-feet Equa- torial was apphed to the Seven-feet Instrument, in order to MDCCCXXVI. b a Mr. South's observations of the apparent distances obtain the advantage of higher magnifying powers. By this change they stand in order 92, 157, 181, 327, 413, 5i3, and 787 ; the commonly used power being 181 : a rigorous examination assured me, that the value of the one micrometer, was also the value of the other. In the subsequent pages will be found observations of about 160 double and triple stars, hitherto (as far as I know) undiscovered : their apparent right ascensions and declina- tions are, I hope, generally accurate to the nearest minute : and should occasionally a greater error be detected, some indulgence will I trust be extended to me, for they were generally found at a considerable distance from the meri- dian, when extreme unsteadiness of the stars, and unwilling- ness to quit my observatory, rendered sweeping for new double stars my only mode of passing the night in it : as however they have been found on subsequent evenings from the data here given, no difficulty in identifying them, can reasonably be expected. In the former Paper, 37 double and triple stars were selected as entitled to peculiar notice, these it was my inten- tion to have subjected individually to a rigid investigation ; owing however to the almost unprecedented bad weather of the last autumnal and winter months, go only of them could be re-measured ; and the observations, which are here sub- joined as an Appendix, although not so complete* as I could have wished, will still I hope be deemed not unimportant. The arrangement is somewhat different from that pursued on the former occasion : instead of individual measures being * The Appendix contains observations of thirty-six stars j six however of them offerno particular interest, and were measured inadvertently, under an idea that they were vn-measured stars. and positions of^fSS double and triple stars y &c. 3 presented to public view, the mean result of each night's work is here noted ; but as the number of observations, and the differences between the extreme measures of eac'i series are also specified, it is hoped that the alteration will be satis- factory to the Society. As in these observations I have not had the powerful aid of Mr. Herschel, it has been my endeavour as far as possible to compensate for the loss ; hence, instead of taking ten indi- vidual observations both of distance and position on the same night, and thereby considering the star measured, I have divided the work generally assigned to each star between two evenings, the better to correct any error which unfa- vourable state of atmosphere, inaccurate micrometrical read- ings, or particular bias of judgment might entail ; and when the results have exhibited discordances greater than seemed justified by the difficulty of the observations, a third, or even a fourth night's determination has been found useful. To the observations contained in the former Memoir, pecu- liar interest was attached by the comparison of them with the results obtained by other astronomers ; of which by far the most important were those derived from the labours of Sir W. Herschel ; but as the observations which are re- corded in the Philosophical Transactions are (from circum- stances before * adverted to ) of themselves inadequate to furnish the final results arrived at by that illustrious astro- nomer, it is grateful to me, and doubtless will also be to the Society, that the kindness of Mr. Herschel has supplied the necessary information ; thus the existence of fresh connected systems is substantiated, and adegree of /)r^5^w^ importance con- ferred on the following pages, which he alone could bestow. * See PhU. Trans, for 1824, Part IIL page 20. 4 Mr. South' s observations of the apparent distances The noble liberality of the Russian Government having re- cently put Mr. Struve in possession of an instrument much more powerful, and far more appropriate, for pursuing this department of astronomical* enquiry, than those with which his published observations were made, I have not deemed it right, as heretofore, to refer to his earlier, yet still valuable determinations, the general accuracy of which may well be cited as proofs of what industry and perseverance may achieve, although supported by comparatively slender instru- mental assistance. I have said that the accompanying observations were made partly at home, and partly abroad ; the latter remind me of a pleasing duty : — the Board of Longitude of Paris, and Government of France, have claims upon me too great to remain unnoticed, the one for having requested, and the other for having acceded to me the permission of introduc- ing into France, free of all duty (sans conditions) j whatever astronomical instruments I thought proper ;"f and so effectual were the arrangements of the Director General of the * The investigation of parallax by direct observations of double stars, not having yet been seriously entered upon, although recommended by Sir W. Herschel nearly fifty years ago, and the importance of it having been warmly pressed upon me by Monsieur le Marquis de la place — a continuous series of observations of the most interesting double and triple stars seeming necessary — and fresh determina- tions of the orbits of Saturn's satellites being wanted — it was my wish to have pro- cured more extensive means than I possess, to have attacked the one, to have with greater facility followed up the other, and to have furnished the necessary observa- tions of the satellites alluded to ; — the overtures however for an object-glass of twelve inches diameter, and twenty feet focal length (Paris measure), with which I had proposed to construct an equatorial, similar to that of which an engraving is given in the former paper, were most unexpectedly arrested in limine, by Mr. Fraunhofer declining to supply me with one, unless accompanied by apparatus provided by himself — a useless augmentation of expence, which prudence therefore did not authorize me, to incur. f The like indulgence was granted me for the importation of my ordinary bag- gage, travelling carriage, and for whatever I deemed necessary to render my sojourn in France comfortable. and positions 0/4.58 double and triple stars, ^c, 5 Douanes, Mons. le Marquis de Vaulchier, and so extreme the politeness of the principal and subordinate officers of the Customs at Calais, that the importation and exportation of them, were affairs, not of difficulty, but of gratification. It is needless to state, that on the establishment of an observatory by a private individual in a foreign country, many difficulties must be encountered. To Mons. Benjamin Delessert, whose liberality in promoting every thing which has science for its aim knows no bounds, I stand indebted, amongst other things, for whatever comfort my observatory afforded. From the members of the Royal Academy of Sciences of Paris I uniformly received every possible attention, whilst to Messrs. De la place, Arago, Bouvard, Humboldt, and PoissoN, a residence of fifteen months has placed me under obligations of no common order : they were received with pride, and are remembered with gratitude. The Society have now before them, with few exceptions, a re-examination of all the identified double and triple stars described by Sir W. Herschel in the Philosophical Transac- tions ; with the sentiments therefore of the illustrious author of the Mecanique Celeste I will conclude — " Had the labours of Sir W. Herschel been confined to this department of astro- nomy, the discoveries he has made in it would have alone conferred upon him an imperishable name." JAMES SOUTH. Passy ; Rue Franklin, No. \g, Oct. 22, 1825. Mr.SouTH's observations of the apparent distances No. CCCLXXXI. R. A. o^ o"" ; Decl. 45° 23' N. 51 (Bode) Andromedse; Struve, 1 ; II. 83. Double ; 9th and 10th magnitudes. Passy ; October 19, 1824 ; Seven-feet Equatorial. ]^^ = f'.;ty 1 5' ot I SI: z (-.li } E— ^ "«»'- Night favourable. Passy; November 16, 1824 ; Seven-feet Equatorial. 9th and 10th magnitudes. j 8':: 'Eil:^?'.;78}E«remely difficult. Position r: 3° 49' nf Distance = 4".37i Passy ; September 27, 1 825 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position = 4®32'«/'| 5 Obs. Distance r= 5".oii j 5 Obs. DifF. = 1° 40' \ Extremely difficult. DifF. = o".3i2 5 (South.) Position = 5° 45' »/| 5 Obs. I DifF. = 1° 35' ) Excessively difficult. Distance = s'^oS/ | 5 Obs. | DiflF. =: o".649 ) (Capt. Beaufort.) Passy; September 28, 1825 ; Seven-feet Equatorial. 9th and nth magnitudes. Position = 5O47' nf\ 5 Obs. I DifF. = 2** 15' ) „ • 1 j-o: i- Distance = ^'.U? \ 5 Obs. | DifF. = o".4oS J Excessively difficult • Mean Result. Position 4° 39* nf ( 25 Obs. ) ; Distance 5" -009 ( 25 Obs. ) Epoch 1825.29. There is no evidence of any change in the relative situa- tion of these stars. Sir W. Herschel's observations give 5° 48' nf for the position, Feb. 26, 1783, and 6° 44' nf on Sept. 1, 1802; neither differing more than 205' from the present position. The distance also remains unaltered. (H.) and positions 0/4,58 double and triple stars y &c, 7 No. CCCLXXXIL R. A. o** 5- ; Decl. 61** 49' N. Struve, 3 ; 1789 ; 214. Double ; 8th and 8^ magnitudes. Passy; October 21, 1824; Seven-feet Equatorial. Position = 85° 37' sf\ 5 Obs. ( DifF. r= i«'44' 7 Distance = i8".i 1 2 | 5 Obs. | DifF. = i".i30 j Passy; November 16,1824; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 86° 4' «/ I 5 Obs. I DifF. = o<» 56' ) Distance = 1 8".263 | 5 Ottfe. | DifF. = o".72i ) ' Mean Result. Position 85° 50' sf\ Distance 18". 187 ; Epoch 1824.83. No. CCCLXXXIII. R. A. o^g'-, Decl. 15^ 32' N. Nova ; Double ; 9th and 11th magnitudes. Passy; September 15, 1825 ; Seven-feet Equatorial. Position = 40° 58' sp I c Obs. I DifF.= i° 42' ) t7__ •„„, .-a- ,, Distance = ?2".io9 | 5 Obs. | Diff. = o".6oi ] Excessively difficult. The small star scarcely bears any illumination. Passy; October 12, 1825; Seven-feet Equatorial. 9th and 11 th magnitudes. S!iSc" ^ ?f°j;; ''\\ O^L I Eiff! ^ ^.ir. } excessively difficuU. Observed on the meridian with 157. Night fine. Mean Result. Position 39^ 4!4} sp; (lo Obs.) ; Distance i2".ioo (lo Obs.) Epoch 1825.74. 8 Mr, South* s observations of the apparent distances No. CCCLXXXIV. R. A. o** lo™ ; Decl. 37° 20' N. Struve, 6; V. 85. Double; 7th and 12th, or 15th magnitudes. Passy; October 19, 1824 ; Seven-feet Equatorial. position = 76° 36' «/ 5 Obs. I DiiF. = o* 35' > Excessively difficult Distance = 46".o8o 5 Obs. | DifF. = i".2z6 5 excessively aimcuit. Night very fine; but the small star will scarcely bear the least illumination. Passy; November 25, 18*24; Seven-feet Equatorial. 8th and 15th magnitudes. Position = 77*> 3' n/| 5 Obs. | Diff. = 0° 55' Excessively difficult. All attempts to obtain measures of distance unsuccessful. Passy; December 10, 1824 ; Seven-feet Equatorial. 7 th and 12th, or 15 th magnitudes. Position = 76' 45' nf I 5 Obs. I Diffi = 0° 45' 1 E„-essivelv difficult Distance = 44".943 | 5 Obs. | DifF. = o".86s / Excessively ditticult. Passy ; January 6, 1 825 ; Seven-feet Equatorial. 7th and 12th, or 15th magnitudes. Distance = 46*.520 | 3 Obs. j DifF. = i".iS4 Excessively difficult. Mean Result Position 76^ 48' «/(i5 0bs.); Epoch 1824.90; Distance 45".744 (iS Obs.); Epoch 1824.92. The position Jan. 16, 1783, was 79° 24' nf, and according to a single measure taken by Sir W. H. Aug. 19, 1783, the distance was then 31". The difference of 2° 36' in angle affords no proof of change ; but 15" in a distance of 46", or a third of the whole, is too great to be owing to error of observation, even when the diflficulty of the star is considered. (H.) distances and positions 0/4,58 double and triple stars y ^c. 9 No. CCCLXXXV. R. A. o^ 16" ; Decl. 31^ 31' N. Nova; Double; 10th and 11th magnitudes. Passy ; September 15, 1825 ; Seven-feet Equatorial. • Position = 81^^49' */| S Obs. I Diff.= 1O8' 7 Excessively difficult. Distance = 5 .116 | 5 Obs. | DilF. z= o .745 j ' Observations to be received with caution. Passy ; October 7, 1825 ; Seven-feet Equatorial. lOth and 1 1th magnitudes. Position = 80" zi' sf\ 5 Obs. . Diff. = f 19' 7 5^^ „ Distance z= 6".o35 I 5 Obs. | Diff. = d'.giz ] ^o^^h. Position = 82° c' «/ 1 5 Obs. Diff. = 1" 5' 7 ^ , „ Distance = s".756 | 5 Obs. Diff. = o".986 j ^^P*' ^^^^'°*'^- Measures deemed excessively difficult by both Observers. Mean Result. Position 81* 25' sf\ (15 Obs.) ; Distance ^\6s6 (15 Obs.); Epoch 1825.74. No. CCCLXXXVI. R. A. o^ 23"^ ; Decl. 27° 32' N. Nova; Double ; 9th and 9^ magnitudes. Passy; December 29, 1824; Seven-feet Equatorial. Position = 74° 47' nf | 5 Obs. Distance = 42".228 | 5 Obs. Diff. = 1° 28' 7 ^.^ . Diff.=o".986j^^^"^*- Night fine, but neither star bears a good illumination. Passy ; January 6, 1825 ; Seven-feet Equatorial. Equal ; each of the 10th magnitude. Position =740 22' sp or Ji/I 5 Obs. I Diff. = 0° 25' 7 xT.^A\«i...u Distance = 42''.335 I 5 Obs. | Diff. = i".85 1 \ ^^^ ^^®<^"^*- Night favourable, but both stars very faint. Mean Result. Position -j/^ 34' sp or nf\ Distance 42".28i ; Epoch 1825.00. MDCCCXXVI. c lo Mr. South* s observations of the apparent distances No. CCCLXXXVII. R. A. o^ 26™ ; Decl. 17° 6^ N. Struve, 8 ; Hist. Csel. 478. Double ; equal ; each of the 10th or 11th magnitudes. Passy ; October 19, 1824 ; Seven-feet Equatorial. 5 Obs. I Diff. = i".587 \ Extremely difficult. Position =37** 45' sp or nf Distance s=:42".7 86 Night very fine. Passy; November 16, 1824 ; Seven-feet Equatorial. 11th and 11 J magnitudes. Position =38° 18' 50 I 5 Obs. Diff.=o°46'7n •,.•«- 1 Distance=42".23S | 5 Obs. Diff. = i"9l 3 J Excessively difficult. Stars steady j Evening favourable. Mean Result. Position 38° 1' sp or nf; Distance 42".5io ; Epoch 1824.83. CCCLXXXVIII. R. A. o** 27"* ; Decl. 29° 1' N. Struve, 9 ; Hist. Csel. 307. Double; 9th and 11th magnitudes. Passy; October 23, 1824 ; Seven-feet Equatorial. Position =50" 27' nf\ 5 Obs. I Diff.=6° 18' 7 ^ ,, • ,. Distance=7".988 | 5 Obs. | DifF. = i".2Soi^^ *^^ meridian. The measures are so excessively difficult, that I have but little confidence in the results. North preceding, in the field with this, is a faint double star of the 4th or 5 th class ; but it is not measurable with this instrument. Passy ; November 16, 1824 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position =57° 32' nf\ 5 Obs. I DifF.=2*' 7' ) ^^ ,, ... Distance=7''.o4o ^ \ 5 Obs. | DifF. = i'.322 \ ^^ *^^ ra^n^^^n. Measures of such difficulty, that I consider them little else than approximations ; the small star will not bear the slightest illumination j would be a proper object for Mr. Herschel's 20-feet Reflector. and positions of 4)6^ double and triple stars, &c, ii No. CCCLXXXVIII. continued. Passy ; December 23, 1824 ; Sevea-feet Equatorial. 9th and 12th magnitudes. Position =55° 4' nf Distance =6".o69 5 ^k'- I n-ff "^" ^^' T Excessively difficult. 5 Obs. I Difr. = o .553/ ^ The small star scarcely bears any illumination ; night at present favourable. Mean Result. (The observations of October 23 being rejected) Position 56° 18' nf; Distance 6".554 ; Epoch 1824.88. No. CCCLXXXIX. R. A. o** 38'" ; Decl. 50° sf N. 78 (Bode) Cassiopeiae; Struve, 14; I. 40. Double ; 8-^ and 9th magnitudes ; the small star does not bear a good illumination. Passy ; October 23, 1824 ; Seven-feet Equatorial. Position =55« 38' sf\ 5 Obs. I Diff.=:2° 30' 1 ,, ..n: ,, Distance=3^os3 | 5 Obs. | Diff.=o".6o, | ^^^^ difficult. Passy; November 16, 1824; Seven-feet Equatorial. 8^ and 9th magnitudes. Position =57° 7' sf\ 5 Obs. I Diff. = 3° 50' 7 ^ ^ 1 j-n: 1.. Distance=i(236 | 5 Obs. | Diff. = I".io6 j^^*^^""^^^ ^**="^*- Passy; September 28, 1825 ; Seven-feet Equatorial. 8 J and 10th magnitudes. Position =59° 59'*/ 1 5 Ohs. I Diff.=:i» 7' ? ^ ^ , ,.a: ,. Distance=/.4i8 | 5 Obs. | Diff.=o".;8i j Extremely difficult. Mean Result. Position 57° 35' sf {^ Obs.) ; Distance 2." 569 (15 Obs. ) ; Epoch 1825.14. Sir W. Herschel's position May 4, 1783, was 50® 30' sf. His distance J of a diameter, corresponding to about 2" 0/ 2"^. A slow change of position (+ 0^.170 per annum, direct or in the direction nfsp) is rendered the more probable in this star, as the earlier observation is marked " very exact." (H.) 12 Mr. South's observations of the apparent distances No. CCCXC. R. A. d^ 49™ ; Decl. i6« 38' S. _ Struve, 17; Hist. Cagl. 249. Double ; 9th and 10th magnitudes ; both bluish, and do not bear a good illumination. Passy ; November 25, 1824 ; Seven-feet Equatorial. Position =58° 6' *o I 5 Obs. I DiiF. = 3° 2' 7 ,. ,.^ ,, Distance=7".749 | 5 Obs. | DifF.=o".505 l^ery difficult. Night unfavourable J and during the observations of position, very bad. The weather being much improved, the instrument was again placed upon this star, and the following measures were obtained, the star being half an hour west of the meridian : Position=56° 2' sp\6 Obs. j DifF. = l° 53'. Difficult. Passy ; November 29, 1824 ; Seven -feet Equatorial, 9th and 1 0th magnitudes. Position =57° 2/ sp 5 Obs. I Diff. = 20 . . Distance=7 .814 5 Obs. | Dm.=o .841 j ■' The evening is now become so bad, that the observations are discontinued. Mean Result. Position 57° i sp{i60hs.)\ Distance 7."78i ; Epoch 1824.90. No. CCCXCI. R. A. 0^ 50" ; Decl. o° ii' S. Struve, 19 ; P. O. 251. Double ; 9th and 10th magnitudes ; small, blue. Passy ; October 25, 1824 ; Seven-feet Equatorial. c Obs. Diff. = i°48' ) p ^ , ,._ , 5 Obs. DifF. = i".8o3 \ Extremely difficult. Night unfavourable. Passy ; November 3, 1824 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position =24° 43' np Distances: 19". 266 Position =27** ^ np \ ^ Obs. Distance = 1 8".8 88 | 5 Obs. ^^.z'Z^\''''y^<^'^^'■ The small star is blue, and does not bear a good illumination. and positions of 4;58 double and triple stars, &c. 13 No. CCCXCI. continued. Passy ; October 11, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position =27«» 34' no I 5 Obs. I DifF. = i° 22' ) „ - , j.^-^ ,^ Distance = i8".so4 ^ \ 5 Obs. | DiflF.=o".48i \ Excessively difficult. Night foggy ; the small star at times very faint. Mean Result. Position 26° 27' np (15 Obs) ; Distance iS".S66 (15 Obs.) ; Epoch 1825.17, No. CCCXCII. R. A. o^ 56"^ ; Decl. 6" 25' S. Struve, 21 ; III. 73. Double ; 10th and 12th, or 15th magnitudes. Passy ; October 30, 1824 ; Seven-feet Equatorial. Position =840 22*/ c Obs. DifF. = 3» c' }„ • , j-n: i Distance=i5'.S5i 3 Obs. DifF. = I".322 J ^^^"^'^^^^ ^^<^"lf- Observations liable to some inaccuracy ; neither star bears sufficient illumination j night tolerably fine. Passy ; November 9, 1824 ; Seven-feet Equatorial. Position =80° 7' sf\ 5 Obs. Distances: i3".325 | 5 Obs. 10th and 15 th magnitudes. DifF. = 2° 10' J 20 minutes east of DifF. =o".962 ) the meridian. These measures were procured with such extreme difficulty, that I fear they de- serve but little confidence ; the night is rather hazy, and neither of the stars will bear the least illumination. Passy ; December 6, 1824 ; Seven-feet Equatorial. lOth and 1.5th magmtudes. Distances I2".834 | 5 Obs. [ Difi^. = i".467. Excessively difficult. The smaller star is now so extremely obscure, that no observations of position can be gotten. 14 Mr. South' s observations of the apparent distances No. CCCXCII. continued. Passy ; December 23, 1824 ; Seven-feet Equatorial, loth and 12th magnitudes. Position =83° 37' sf\ 5 Obs. I DifF.=oO 56' ) tj^4...-«,«i„ ^;fl;.„u Distance=i2".72+ | 5 Obs. | DiflF. = i".298} Extremely difficult. Night fine, but the stars will not admit of sufficient illumination. Mean Result, Position 82» 42' sf (15 Obs.) ; Epoch 1824.89 ; Distance i2".89s.(i8 Obs.) ; Epoch 1824.90. The position and distance of 1783 are 89° 12' sp. (Jan. 31), and 14,".82 (Aug. 21). A diminution of distance of 2" in so difficult a star is not very material ; but a change of 8° 6' in the angle, accompanied by an alteration of the quadrant from sp to sf argues a sensible motion in one or both of these stars. (H.) No. CCCXCIII. R. A. o^ ^6^ ; Decl. 31° 13' N. &" Piscium ; Struve, 23 ; V. 16. Double; 6th and 15th magnitudes. Passy ; December 7, 1824 ; Seven-feet Equatorial. Position =2 1** %' ±np\ 2 Obs. | Diff.=o«>45' Excessively difficult. Distance about one minute and a half by estimation. The small star bears no illumination, and the position here given may be one or two degrees in error. The position in Nov. 1781 was stated at 15° 28' ; but no reliance can be placed on this measure, and the evidence of change is open to great suspicion ; indeed there may be some doubts as to the identity of the star. (H.) and positions 0/4,58 double and triple stars, &c. 15 No. CCCXCIV. R. A. o^ 58™ ; Decl. sT 41' S. 160 (Bode) Ceti ; Struve, 28 ; EQst, Gael. 392. Double ; 9th and 10th magnitudes. Passy ; October 25, 1824 ; Seven-feet Equatorial. Position =580 28' np 1 c Obs. I DiflF.=:6° 35' ) t? 4^ 1 j-a: 1* Distance=;".i59 ^ | 5 Obs. | DiflF.=o".336l E^^^emely difficult. Night unfavourable, Passy ; November 3, 1824 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position =5 6<» ii' np c Obs. I DiiF. =40*48' \ j. ^ 1 j-a: i. Distance=4".i30 5 Obs. | Diff.=o".72i J Extremely difficult. Mean Result. Position 57° 19' np ; Distance 4".i44 ; Epoch 1824.82. No. CCCXCV. R. A. !•» 3"^ ; Decl. 31° i N. Struve, 30; IV. 120. Double; 8th and 9th magnitudes. Passy ; October 23, 1824 ; Seven-feet Equatorial. Position =21° 37' sp I c Obs. I Diff.=o° 35' ) « ^u j-m 1^ Distance=i8".888 ^ | 5 Obs. | Diff.=o".8J7l ^^*'' ^^^""^*- Passy ; November 9, 1824 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position =21° 50' «p Distance = 1 9".735 c Obs. I DifF. = 2<> 53' } T^-n: i* SObs. |DifF.=o".72il^^^^^*- Night unfavourable. Passy ; December 6, 1824 ; Seven-feet Equatorial. 8th and 9th magnitudes. Distance = 1 9".495 | 5 Obs. { DifF. = 0^.673. Rather difficult. Mean Result. Position 21° 43' s p ; Distance 19 '-373 (15 Obs.) ; Epoch 1824.86. This star is unchanged; the measures of 1783 diflfering from the present only 43' in position, and — i"in distance. (H.) i6 Mr, South's observations of the apparent distances . No. CCCXCVI. R. A. 1^ 5" ; Decl. S** 33' S. Struve, 33 ; IV. 77. Double ; 8th and 15th magnitudes. Passy ; October 30, 1824 ; Seven-feet Equatorial. Position =670 s'np | 3 Obs. | DifF.=40 30') e„,_„:„_i„ difficult. Distance = 1 9". 1 63 ± single observation ] iixcessiveiy aimcuit. In these results I have but very little confidence ; night tolerably good. Passy ; October 12, 1825 ; Seven-feet Equatorial. 8th and 15th magnitudes. Position S67" 53' n p c Obs. I DifF. = 20 ic' ) „ . , ,.«- ,^ Distance=2o".o36 5 Obs. | Diff.=o".72i J E^'^sss.vely difficult. Observed on the meridian with 92; with 181 and 157 the small star could not be distinguished. Night favourable. Mean Result. Position 67° 34' np (8 Obs.) ; Distance I9".89i (6 Obs.) ; Epoch 1825.30. The measures of 1783 are 63° 24' np and 19 or 20" ; nei- ther giving ground to suppose a material change. (H.) No. CCCXCVII. R. A. 1^ 9" ; Decl. 63" 4S' N. 119 (Bode) Cassiopeiae; Struve, 36. Double ; 8th and 9th magnitudes. Passy; October 23, 1824 ; Seven -feet Equatorial. Position =83** 32' «j) 5 Obs. I DifF. = 2°29' \ Distances: 5 o".440 5 Obs. | DiflF. = i".oio5 Passy ; November 15, 1824 ; Seven-feet Equatorial. 8tn and 9th magnitudes. Position =82«> \\* np Distance =:5o".275 5 Obs. 5 Obs. DifF.=o°27' ) DiflF.=o".6495 Mean Result. Position 82° 53' np ; Distance 5o".357 ; Epoch 1824.84. and positions of 4f5S double and triple stars y &c. 17 No. CCCXCVIII. R. A. 1^ 19" ; Decl. 7' s' N. Nova ; Double ; 7th and 9th magnitudes. Passy ; December 29, 1824 ; Seven-feet Equatorial. F.=oo S7' I . . F. = i".oio5 Position =7° 54' sf\ 5 Obs. Distance=i' 9". 500 \ 5 Obs. DifF.=< DifF. Passy ; January 2, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position =8° 41' sf Distance =1' io".oo5 5 Obs. I DifF. =0® 26' ) •iff. = 1 ''.202 5 S Obs. I Diff. Observed when 1^ 50' west of the meridian. Mean Result. Position 8" 17' sf; Distance 1' 9".752 ; Epoch 1825.00. No. CCCXCIX. R. A. i*" 33" ; Decl. i2« 12' S. X* Ceti ; Struve, 43 ; Hist. Gael. 244. Double ; large, white ; small, blue ; 8th and 8^ magnitudes ; the small star does not bear a good illumination. Blackman-street, December 12, 1823 ; Five-feet Equatorial. Position =0° 6' sf 6 Obs. 1 DifF. = 2° o' ^ Extremely unsteady Distance = 3".95i 5 Obs. j DifF. = 1". 010 5 ^ ^' Observed on the meridian ; but night unfavourable. Blackman-street ; December 30, 1823 : Seven-feet Equatorial. 8th and 8| magnitudes. Position =0° 15' nf Distance =4".436 5 Obs. 5 Obs. DifF.=o° 10' ) DifF.=o".553 5 Mean Result. Position 0° 4' nf; Distance 4".i93 ; Epoch 1823.97. MDCCCXXVI. d 18 Mr, South' s observations of the apparent distances No. CeCC. R. A. 1^ sr ; DecL f 59' S. Struve, 44 ; Hist. Gael. 247. Double ; 7th and 7^ magnitudes. Passy ; November 15, 1824 ; Seven-feet Equatorial. Position =74° 41' sp Distances: 36".749 DifF. = i°4i' 5 Obs. 5 Obs. Observed when 15 minutes west of the meridian. F. = i°4i' ) DifF.=o".8i7| Passy; November 16, 1824: Seven-feet Equatorial. 71 and 8th magnitudes. Position =75» z^,' sp 5 Obs. DifF. = i° 25' ) Distance = ^o'.^^z DifF.=o".697 5 5 Obs. Mean Result. Position 75° 2' sp ; Distance 36".645 ; Epoch 1824.87. No. CCCCI. R. A. 1^ 40" ; Decl. 21° 23' N. 304 (Bode) Piscium ; Struve, 45 ; I. 73- Double ; large, white ; small, blue ; 8th and 10th magnitudes. Blackman-street, December 13, 1823 ; Seven-feet Equatorial. Position =82° 15 */l 5 Obs. I DifF.=3'> 4°' \ Very difficult Distance=3".4i2 | 5 Obs. | Diff.=:o".6oi ] ^^^^ <"nicuit. Blackman-street ; December 31, 1823 ; Seven-feet Equatorial. Position =82° 38^/1 5 Obs. I Diff.=20 35') Extremely difficult Distance=3".344 I 5 Obs. | DifF.=o".432 5 ^^^remeiy aimcuit. 9th and 10th magnitudes. Mean Result. Position 82® 26' sf; Distance s".S78 ; Epoch 1823.98. On Dec. 23, 1782 (1782-98) the position was 77° 24' 5/, being a change of + 5° 2' in 41 years or + o°.i23 per annum. Future observations must decide on the reality of this motion. The distance seems to have undergone no alteration. (H.) and positions of 458 double and triple stars, &c. 19 No. CCCCII. R. A. i»» 42" : Decl. 36** 26' N. 241 (Bode) Andromedae ; Struve, 46 ; I. 89. Double ; 9th and 10th magnitudes ; large, white ; small, blue, and bears only a very slight illumination. Blackman-street ; December 13, 1823 ; Seven-feet Equatorial. Position =71° 8' */ s Obs. I Diff. = i° 13' ) Extremely difficult. Distance =4".243 5 Obs. | Diff.=o".72i J '^'^^"^^"^^^^ °^™^"^^* Blackman-street ; December 31, 1823 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position =71° 36' sf\ 5 Obs. I Diff. = io 55' > r- • t j-/n 1. Distance=;".652 "^ | 5 Obs. I Diff.=o".l8il ^^^""^^^^ ^^®^"1^- The small star is blue, and scarcely bears any illumination. Passy; January 6, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position =72° 3' «/" 10 Obs. I Diff.^i** ^o' } ^ ^ , j-a: 1. Distance=3".878 "^ 5 Obs. | DifF.=o".48i ] Extremely difficult. Night very fine, but the small star bears only a very feeble illumination. Mean Result. Position 71° 42' 5/(20 Obs.) ; Distance 4''.258 (15 Obs.); Epoch 1824.98. The observations of Sir W. Herschel in 1783 and 1802 give respectively 75® 30' sf and 67° 4/ sf for the positions of this star. The present position is almost exactly a mean of these, which renders it extremely probable that the star is subject to no material change. ( H. ) 20 Mr. South's observations of the apparent distances No. CCCCIII. . R. A. 1^ 45" ; Decl. 27° 56' N. Nova ; Double; 8th and 10th maornitudes. Passy ; September 25, 1825 ; Seven-feet Equatorial. Position =750 50'*/ sObs. DifF. = 2°40' )g Distance =5 .802 5 Obs. DifF.=o".745^ Position =76° 8' */ I 5 Obs. I DifF. = 2°43' } r- . -o Distance=5".96, | 5 Obs. | DifF.=o".529j ^^P*' ^=^"'«''^'^- Measures extremely difficult. Passy ; September 27, 1825 ; Seven-feet Equatorial. 9th and 11th magnitudes. DifF.=^6« 19') o DifF.=o".769jSouTH. Position =76° 23' «y I 5 Obs. Distance := 5". 5 97 ( 5 Obs. Position =750 1' sf Distance =:5".333 5 Obs. 5 Obs. DifF. = 8o c' ) ^ ^ c Diff.=o".745i^*P*-^^^^^<'^^- Measures excessively difficult. Mean Result. Position 75° 5^' sf (9.0 Obs.) ; Distance 5".673 (20 Obs.); Epoch 1825.74. No. CCCCIV. R. A. 1^^ 47°* ; Decl. 4o» 30' N. Struve, 48 ; IV. 104. Double; 8th and 10th magnitudes ; small, blue. Passy ; November 15, 1824 ; Seven-feet Equatorial. Position =22* 5S' »/ 1 5 Obs. Distance=2o".628 | 5 Obs. ^mZtfn]^-^^^'- Night fine, but the small star is very faint. and positions of ^sS double and triple stars, &c. 21 No. CCCCIV. continued. Passy ; November 16, 1824 ; Seven-feet Equatorial. 8th and 12th magnitudes. DifF. = i".l5oJV^^d^^^^l*- Position =22 16' n/j 5 Obs. Distance =2o".5 5 3 j 5 Obs. The small star is decidedly light blue ; scarcely visible without illumination, but rendered much more distinct by a moderate one. Mean Result. Position 22° 35' nf; Distance 20^.590 ; Epoch 1824.87. This star appears subject to no change of position, as the angle of 1783 (22° 33' nj) differs only 2' from the present. An excess of i".64 in the present over the earlier measure of distance is not sufficient to authorize any positive con- clusion. ( H. ) No. CCCCV. R. A. 1^ 53" ; Decl. 78° 50" N. Struve, 52 ; 17S9, 223. Double ; 7th and 7-j magnitudes. Blackman-street ; December 9, 1823 ; Five-feet Equatorial. Position =4° 15' n jo I 5 Obs. I DifF.=o* 47' ) Distance=55".370 | 5 Obs. | Diff. = i".si6 5 •••••• Blackman-street ; December 30, 1823 ; Seven-feet Equatorial. 7th and 71 magnitudes. Position =4° 8' »;> I 5 Obs. I DifF.=o° 55') Distances=55".237 | 5 Obs. J DiiF.=:o".962 5 Mean Result. Position 4° 12' np ; Distance 55".303 ; Epoch 1823.97. »a Mr, South's observations of the apparent distances No. CCCCVI. R. A. 1^ 59"^ ; Decl. 25° 5' N. 14 Arietis ; Struve, 56 ; VI. 69. Double ; large, white ; small, blue ; 6th and 10th magnitudes. Blackman-street ; December 9, 1823 ; Five-feet Equatorial. Position = 8° 7' «p I 5 Obs. Distance=i' 45".349 J 5 Obs. 5S— '?,^' \ Difficult. DlfF. = 2'.020 j Stars very steady ; but the evening hazy. Blackman-street ; December 30, 1823 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position =7° 49 n;> I 5 Obs. DiiF.=o° 32' ) Distances i'4s".i67 I 5 Obs. DifF.=o".S29) ...... Mean Result. Position 7° 5^' np\ Distance 1. 45".258 ; Epoch 1823.97. The position and distance of this star in 1783 are stated at 11° 19! np and 1' 29" 28'". The change of position is not material ; but with respect to the increase of distance, it may be remarked once for all, that there is great reason to suspect a considerable instrumental error in all the measures of that early period, exceeding 40", the result being constantly (or most commonly) in defect, and that not unfrequently to a very large amount. The cause probably lies in the con- struction of the micrometer used ;* and its effect is to throw a great uncertainty on the earlier distances of all stars of the 5th and 6th classes. Fortunately these are the least replete with interest. (H.) * It is certainly not from a wrong determination of its scale. and positions 0/4,58 double and triple stars, &c. 23 No. CCCCVII. R. A. 2^ 0"^ ; Decl. 1° 18' S. Struve, 57 ; Hist. Gael. 39^- Triple ; A of the 8th ; B of the 9th ; and C of the 8th magnitudes. The star B is decidedly blue, and bears a tolerable illuminatioa. Measures of AB. Passy ; November 25, 1824 ; Seven-feet Equatorial. Position =20" 2z' sp I 5 Obs. Diff.=:2° 2' 7 Distance= 5".oo8 | 5 Obs. Diff.=o".937 j Passy ; December 7, 1824 ; Seven-feet Equatorial. 8th and 9th magnitudeSi Position =18° 41' «;> J 5 Obs. j DifF.=20 15' ) Distance=:4.".905 | 5 Obs. j DifF.=o".962 5 • • * • . Measures of AC. Passy; November 25, 1824 ; Seven-feet Equatorial. 8th and 8th magnitudes. Position=i2'»5/n/>or5/| 5 Obs. Diff.=:o''29' 7 Distance=4'3".586 | 5 Obs. DifF.=o".673 j • • • Passy ; December 7, 1824 ; Seven-^feet Equatorial. Equal ; each of the 8th magnitude. Position = 12° 40' «;? or «/ 1 5 Obs. j DifF.=o°i5' \ Distance=4' 4".573 | 5 Obs. | Diff.= i'.oio j Mean Result. ofAB. Position ig** 31' 5 />; Distance 4^.956 of AC. 1 s** 48' np or sf 4' 4^.079 Epoch 1824.92. 24 Mr. South' s observations of the apparent distances No. CCCCVIII. R. A- 2^0^" ; Decl. 19° 28' N. Struve, 58 ; III. 68. Double ; 9th and i ith magnitudes ; small, blue. Passy; November 15, 1824; Seven- feet Equatorial. Position =60° 25'*/ 5 Obs. DifF.= i° 29' ) ,. ,.„. ,^ Distance=8".633 5 Obs. DifF.=:o".673 j The small star bears but the slightest illumination. Passy ;N ovembei 16, 1825 ; Seven-feet Equatorial. 9th and 12th magnitudes.* Position =57° 13' sf Distances 9".27 1 5 Obs. r).fr'_ II J > Extremely difficult. 5 Obs. DifF.=o".529 3 The accuracy of these results perhaps a little questionable ; the smaller star does not admit of the least illumination. Mean Result. Position 58** 49' sf'. Distance 8^952 ; Epoch 1824.87. In 1783 the measures of this star v^ere, Position 55° 42' 5/; Distance 8" s'" ; so that no material change in it has taken place. ( H.) No. CCCCIX. R. A. ^^ 5°* ; Decl. 56° 41' N. X Persei ; Struve, 6s ; VI. 19. Double; 7th and 12th magnitudes. Passy ; December 8, 1824 ; Seven-feet Equatorial. Position =47° 33'«/l 3 Obs. j DifF.=:4'' 20' Excessively difficult. The small star will bear no illumination ; measures of distance cannot be procured ; night not very favourable. and positions of 4f5S double and triple stars y &c, »& No. CCCCIX continued. Passy; December 18, 1824; Seven-feet Equatorial. 6th and 12th magnitudes. The small star will bear but. + Single measure. Excessively difficult. Night tolerably fine j but the star is not measurable. Passy ; November 25, 1824 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position=22° 28' np. ^f; Single measure. Night unfavourable ; no more observations can be gotten. Passy ; December 10, 1824 ; Seven-feet Equatorial. 8th and 12t.h magnitudes. Dsition =22° 20' np 5 Obs. I ^^-^^S^ if J Excessively difficult. istances=i2 .219 5 Obs. | Diff. =0.8895 ' The small star becomes invisible under the slightest illumination. Passy : December 23, 1824 ; Seven-feet Equatorial. 7th and 12th magnitudes. Distances 11'. 190 | 5 Obs. | Diff. =: o".36o. Excessively difficult. The small star, which is blue, will not bear the least illumination. Mean Result. Position 22" 24' «/> (7 Obs.) ; Epoch 1824.92 ; Distance ii".704 (10 Obs.) ; Epoch 1824.96. The measures of 1783 are Pos. 22° 24' np ; Dist. = 1 i".s. The position not differing at all, and the distance only 4-tenths of a second from their present values,— a remarkable coin- cidence. (H.) ^ Mr. South' s observations of the apparent distances No. ccecxiii. r: a. 2^ 22™ ; um. d» 19' n. Struve, 74 ; Hist. Gael. 48. Double ; 7i- and 8th magnitudes. Blackraan-street ; December 12, 1823 ; Five-feet Equatorial. Position =530 14' .;, I 5 Obs. I Diff. = i° 5' \ Night unfavourable. Distance =14". 347 | 5 Obs. | DifF.=si".i05 > « Blackman-street ; December 30, 1823 ; Seven-feet Equatorial. Position =:53» 32' sp \ 5 Obs. I Diff.=o* 38' | Distance=i4".3i8 | 5 Obs. | Diff.=o".48i3 8th and 8^ magnitudes. Mean Result. Position 5S<> ^s' sp\ Distance 14". 332 ; Epoch 1823.97. No. GGCCXIV. R. A. ^^ 22™ ; Deel. 17° 37' N. Nova ; Double ; ibth Mtid 11th nl^gnitudes. Passy ; October 16, 1825 ; Seven-feet Equatorial. Position =89° ii'n/l 5 Obs. I Diff. = 2°4o' ) Excessively difficult. Distance =8".446 \ 5 Obs. | DifF.=o".793 5 ' Observed when on the meridian with 157; with 181 the Stars were scarcely visible when the field was unilluminated. Night foggy. From this night till the 22nd of this month, when the observatory at this place wSs dismantled, I was prevented by a succession of bad weather from obtaining a second series of observations of this star. and positions of 458 doubh mi triple st^rs^.^Ciyy 2^^ No. CCCCXV. R. A. 9* 51*" ; Decl. i8» 5' N. Triple ^ A 9th, B 9i,^i4 gpf fj^e 1^ c^ i^th^jnagnit^^ Passy ; October li, Wi^ ; Sevea-fe^t Equatorial. Measures of A B.<\* '^c yi- nohiBoH fry. '; r =::'r>(ii,l These stars bear but a very i|idiff(^rent illumination. Measures of AC Same date and Instrument. fry. ; r =r:'r>(ii,lxiCi Position =:28<» 48' s/ 5 Qbs. Distance =2".875 f 5 Obs. Position =31° 29* 5/> Distances I' 6".256 2 Obs. I Diff.=o° S2M _. . , ,.^ . 2 Obs. I Diff.=o".24o5 Excessively difficult. The star C is so extremely indistinct, that the results must be regarded as mere approximations. From this date till the 22nd of October, when the observatory was taken down, I could not obtain ^ny observations of this star. iitf 31™ ; Decl. $9'" 3i'N. Struve, 78 ; IV. 64. Triple; A of the 8th, B of the ,^th, .^n^ .fi pf | Jiie ^^U magnitudes. ' , ^^^ Measures of A B. B lack man-street ; December 20, 1823 ; Five-feet jl^u^tori^l. Position =6i* i' sp | 5 Obs. I DifF. = i*' 24' ) Distance=22".534 '5 Obs. | DiiF.=o".885 \ Measures of jAC.iucjt i>;j'. Same date and^Instmmenfi"^ j^^J-osition =5^056',;, 3 Obs. Diff.=o«j^',|3(;£^ cj Distance =4. 26 .630 3 Obs. Diff.=o".4ii) -v «• » • ', t • . C being to the south of A.'^ '^ K/' ^ so Mr. South's observations of the apparent distances No. CCCCXVI. continued. Measures of A B. 4^3hfitTrrQnr:r rftn i J- Blackman-street ; December 30, 1823 ; Seven-feet Equatorial. .siiiia»£ifi; 9th and 10th magnitudes. Position =59® 58' sp Distance=23".233 5 Obs. 5 Obs. Diff. = 2°2o' ) ,, ..- ,^ The small star bears only a very feeble illumination. Measures of A C. Same date and Instrument. 9th and 5th magnitudes. Position =53" 51' «;» J 3 Obs. Diff.=o° 42' \ -> ''^ Distancer=/25".454 I 3 Obs. DiiF.=:o".6oi j ' The star C being to the south of the star A, , j ^ , Mean Result. of AB. Position 60° so' sp ; Distance 22".883 of A C- Position ss^ 53' sp ; Distance 4' 26".04a Epoch 1823.99. 1783, March 8. Position of A B $1° Bl' sp ; Distance 22".o, giving no reason to suspect any sensible change in this star (H.) No. CCCCXVII. R. A. 2«^ 32™ ; Decl. 66'' 45' N. Struve, 80; Hist, Cael. 371. Double ; 93- and 10th magnitudes ; the small star bears but the most feeble illumination. Passy ; December 18, 1824 ; Seven-feet Equatorial, Position e=5*' i}8' «^ Distances: 1 6".5 85 5 Obs 5 Obs. Slff:;°'.^l'z}verydi3o' ) „ • 1 .•«• 1^ Distance=3".200 | s Obs. | Diff.^o-.ip*} Excessively difficult. Observed on the meridian with 157. Night very hazy. October 22nd. A succession of cloudy nights since the 16th has prevented me getting another series of observations : the measures are difficult ; but the mean will I apprehend not prove very remote from the truth. Mean Result. Position 24* il'np{io ObsJ; Distance 2".903 ; Epoch 1825.78. Position =s20*> lo' np I lo Obs. Distances I ".47 2 J 6 Obs. $t . Mr. South's observations of the apparent distances No. CCCCXIX. R. A. ^ 46^ ; Decl. 52° 15' N. "^5 (Bode) Persei ; Struve,'84 ; ^. 38. Double ; 9^ and ic^H.magnitudes ; very close, Passy ; January 6, 1825 ; Seven-feet Equatorial. Position=22°28'no I 5 Obs. DifF.=:3°4o' ) - . , ,.«- ,, Distaiitfe=i".i42 | 5 Obs. DiiF.=o".l64} ^^"^'^^^^ **^®^"^'' Night extremely favourable; but unfortunately a considerable part (perhaps one-third) of the object-glass is rendered useless by the interference of the trans- verse timber, which connects the eastfern alid tvestern sides ©f theobsefvatory. Passy; January 17, 1825; Sev«Jn-feet Equatorial. "^ 9th and ' 1 0th magnitudes. Di£=o''.456} Excessively difficult. Night very clear,fbut the stars unsteady. -J^aeiljiy f , :«January 19, 1825 ; Sevenf»feet Equatorial. 9th and 10th magnitudes. Position =2io 9' np\ 10 Obs. | Diff. = 2" 42' J Excessively difficult. Distance=i .320 j .51 Obs.; IsDiitisio .601.) ' , ., Observed with 173 : night fine. Mean Result, sm Position 21'' 1' np (a^Obs.); Distance i'\s^i (i6.0bs.) ; Epoch 1825:03. The earlier measures of this star compared with the pre- sent offer a discordance. In 1783 the position was stated at ^'^24' 7z'/> ; in 1804, by a mean of two measures agreeing well, 20° 34' np. It is therefore probable that the first mea- sure might be in error, which from the extreme closeness of the stars might well happen. It should be re-examined some years hence. (H.) and positions of 458 double and triple stars y &c. ss No. CCCCXX. R. A. 2^ 42™ ; Decl. 37° 36' N. 20 Persei ; Struve, 8^ ; III. 60. Double ; 6th and 12th magnitudes ; small, blue, and very .faint, but unquestionably becomes more distinct by slight illumination. Passy ; November 21, 1824 ; Seven-feet Equatorial. DifF; = J".2^98}^^'7^'^'="^** Position =34" 2'' *p I 5 Obs. Distance = 1 4".049 | 5 Obs. Passy ; December 10, 1824 ; Seven-feet Equatorial. 6th and 12th, or 15th magnitudes. Position =33° 38' sp 5 Obs, Distance = 1 3".7 24 | 5 Obs. DifF.= i°48' I T, ^ 1 j-^ ,. DifF.=o".962 5 Extremely difficult. Mean Result. Position 83° 50' 5^ ; Distance 13".886; Epoch 1824.91. In 1783 the position v^as 30° 30' sp^ a measure which is confirmed by an observation in a 20-feet sweep in the same year, where it is stated at 30° sp. The distance i4".03. There is therefore no evidence of material change in this star. (H.) No. CCCCXXI. R. A. Q^ 46™ ; Decl. 43° 47' N. Struve, 86; Hist. Ca2l. lai. Double ; 9th and 10th magnitudes; small, blue. Passy ; November 15, 1824 ; Seven-feet Equatorial. Position =26" 41' np 1 z Obs. I Diff. = i'> 57' } ,, ,.^ . Distance=28".i53 | J Obs. | DifF. = i".i78} ^^'^ difficult. Night fine; but the small star bears only a very slight illuminatiou. Passy ; November 16, 1824 ; Seven-feet Equatorial. lOth and llth magnitudes. Position =26« 52' np f 5 Obs. I Diff. = 3'» 18' ) ^ ^ 1 j-n: 1 Distance=28".67o | 5 Obs. | DifF. = 2".7i7 J ^^^^^^^h difficult. Mean Result. '^^'^^"^ Position 26° 46' np; Distance 28".4ii ; Epoch 1824.87. MDCCCXXVI. f 34- Mr. South's observations of the apparent distances No. CCCCXXII. R. A. Q^ 48- ; Decl. 51° 38' N. Struve, 87 ; P. II. 220 ; Hist. Gael. 43. ^f{ Double ; 6th and 6^ magnitudes. Blackman-street ; December 12, 1823 ; Five-feet Equatorial. Position =3<*4z' nf Distance =13". 1 35 5 Obs. 5 Obs. DifF.= DifF. ■.= o".3i6j Blackman-street ; December 29, 1823 ; Seven-feet Equatorial. 7th and 8th magnitudes. Position =5° 38' «/ 5 Obs. I DifF.= 2° 35' } ^j. , , , Distance=i2":786 5 Obs. 1 DifF.= o".7i5 J ^^g^t hazy. Mean Result, Position 4° 40' nf; Distance i2".96o ; Epoch 1823.97. No. CCCCXXIII. R. A. 2^ 49" ; Decl. 25" 42' S. 41 (Bode) Appar. Chemic ; South' s Catalogue. Double ; 8^ and 9th magnitudes. Passy ; December 10, 1824 ; Seven-feet Equatorial. Position =51° 2' sp c Obs. I DifF. = i° c' ) „ . ^ ^ Distance=27'.747 5 Obs. | DifF. = ©".553 J Satisfactory. Night very favourable. Passy; December 18, 1824; Seven-feet Equatorial. 8| and 9th magnitudes. Position = 50" 42' *jj I 5 Obs. Distance=27".76i ' | 5 Obs. DifF. = o".962 J Piff-=»"' 3' I Rather difficult. Night at present not favourable. Mean Result. Position 50** 52' sp ; Distance ^f.^B^ ; Epoch 1824.95. and positions 0/4,58 double and triple stars y ^c. 35 No. CCCCXXIV. R. A. 3^ 10™ ; Decl. 19° 8' N. Struve,' 90 ; 11. 76. .obrjlir'unfTT H Double ; 8|- and 9th magnitudes. Passy ; November 15, 1824 ; Seven-feet Equatorial. Position =19** o' sp Distance s=7 ,519 S Obs. I DifF. = 20 ,0' ^ j^.^,. ?Obs. |DifF. = o".865J^'^'^"^*• Passy ; November 16, 1824 ; Seven-feet Equatorial, 9th and 9j magnitudes. Position = 18" 53 sp \ 5 Obs. Distance = 6".554 | 5 Obs. DifF. = z" 20'. Difficult. DiiF. = o".76g. Very difficult. Small star very obscure ; both have a bluish tint. Passy ; February 4, 1825 ; Seven-feet Equatorial. 8J and 9th magnitudes. Distance = f.^^Z \ S Obs. | DifF. = o".553. Satisfactory. Set the micrometer to 29 parts, which with correction for Zero, are equal to the mea- sure obtained on the i6th of November, and found it certainly too small. Mean Result. (The distance observed on November 16 being rejected) Position 18° 56' sp ; Epoch 1824.87 ; Distance 7*'. 501 ; Epoch 1834.98. Measuresof 1782, Dec. 24; Position i5^^4f* sp; Distance 5". 80. These indicate a slight change in angle, and a pretty sensible one ( — 1".7) in distance, considering the closeness of the stars. (H.) S6 Mr. South* s observations of the apparent distances No. CCCCXX V. R. A. s^ 1 2°» ; Decl. 29° 1 1' N. Nova ; Double ; equal ; each of the 9th magnitude. Passy ; October 11, 1825 ; Seven-feet Equatorial. Position = i^r 18' sf or np 5 Obs. I Diff. = o; 53' > Extremely difficult. Distance = 9 .844 5 O l.s. ( Difr. z=. o . 360 ) ■ Neither star bears a good illumination. Night foggy. Observed when 44 minutes east of the meridian. Passy; October 1(), 1825 ; Seven-feet Equatorial. Equal; each of the 11th magnitude. Position =11° 19' np or sf\ 5 Obs. I DifF. = 3° 5' 1 -^ . , ,._ , Distance = io".846 ] ] Obs. | DifF. = d'.z^o] Excessively difficult. With the common observing power of 1 8 1 the stars were not visible : the observa- tions made on the meridian with 157. Night foggy. October 22nd. The discordance between the two sets of distances is too consi- derable ; between^the 1 6th and this day however, the star has not been visible. The instruments are now dismounted. Mean Result. '~ "' '^'^"^o'^'" ^^J* i^^ Position 12° 18' sf or np (10 Obs.) ; Distance 10^345 (10 Obs.) ; Epoch 1825.78. No. CCCCXXVI. R. A. 3^ 18™ ; Decl. 19° 52' N. Struve, 92 ; III. 77. Double ; large, white ; small, blue ; 8th and 11th magnitudes. Blackman-street ; February 1, 1824 ; Seven-feet Equatorial. v. Position = 75^ o'sf\s Obs. Diff. = 2° .5' ) g^^^^^j ^^ Distance =: 8 .077 \ 5 Obs. Dift. = o .48 1 ) ^ Night unfavourable. Passy; November 16, 1824; Seven-feet Equatorial. 8th and 1 Ith magnitudes. Position = 72" 32' sf\ 5 Obs. Distances 7".7 3 7 J 5 Obs. Diff! = o".529| Extremely difficult. The small star is very obscure ; it is decidedly blue. w^ positions of 458 double and triple stars y (^c, 37 No. CCCCXXVI. continued * ^.l^^^^jf,^^^ y^ Blackman-street ; December 29, 1823 ; 3eyen-feet Equatorial. Position — 370 35' sp Distance r= 43".678 7tb and 7h maguitudea. 11=: noiiieo^ r = sDOBlziG 5 Obs. 1 DifF. = 0° 35^') 5 Obs. I DifF. = I ".05 8 5 Mean Result. y.y^ o^^ aoUv^oH Position 37° l' sp; Distance 43".575 ; Epoch 1823.97. $8 Mr. South' s observations of the apparent distances No. CCCCXXVIII. R. A. 3^ 21™ ; Decl. 26° 5/ N. .(jijolfiup^'i Struve, 9s ; f««njil Double; 6^ and 7th magnitudes. Blackman-street ; December 9, 1823 ; Five-feet Equatorial. Position =.0° I' sp\^ Obs. 1 DifF. =0® 35' ) Distance = 1 1".663 | 5 Obs. | DifF. = i".io5 5 Set the position wire to Zero, and both stars remained bisected by it, during their passage across the field. Blackman-street ; December 29, 1823 ; Seven-feet Equatorial. , , 8th and 8^ magnitudes. Position — 0° co' n» c Obs. DifF. =:i»o' 1 f^^„ . „ . . ^ Distance = 1 1-.685 | 5 Obs. DifF. = o".i2oi Occasionally very faint. Mean Result. Position o** 24' «/ ; Distance ii".674; Epoch 1823.97, No. CCCCXXIX. R. A. 3'' 2s» ; Decl. 22^ 45' N. •^'^ \ Struve, 95; Hist. Csel. 31. Double ; equal ; each of 7^ magnitude. Blackman-street ; December 20, 1823 ; Five-feet Equatorial. Position = 54" 40' nfov sp 5 Obs. I DiiF. zr 1° 35' ) Distances I' ii".75 1 5 Obs. j DifF. = i".oio> ...... Blackman-street ; December 30, 1823 ; Seven*feet Equatorial. Equal ; each of 8th magnitude. Position =550 12' »/or s p\$ Obs. { DifF. = !<> 30' \ Distances: i' u".5 30 | 5 Obs. | DifF. = i".i3o5 ...... Mean Result. Position ss'' 26' nf or sp ; Distance 1' 1 1".640 ; Epoch 1823.98. and positions 0/4,58 double and triple stars, &c\A S^ No. CCCCXXX. R. A. 3*^ 26- ; Decl. 44° 12' N. Struve, 97 ; Hist. Gael. 121 ; Double ; 7t and 8th magnitudes. oH Blackman-street ; Dec. 20, 1823 ; Five-feet Equatorial. -or Position = 5" 11'*/ r.v ., Distance =: 4i".672 6 0bs. 5 Obs. Diff. = 0° 40' 7 o .• r . — w .y4/ J j,J ,jj ^iQij Blackman-street ; December 29, 1823 ; Seven-feet Equatorial. b'j. 7h and 8th magnitudes. ^^^^^ ^.^-^^ , Position = 4° 8' sf Distance = 41'. 3 50 5 Obs. I Diff. = i".o82. } • • '^»^"* • Mean Result, Position 4° 39' sf; Distance 4i".5ii ; Epoch 1823.98. No. CCCCXXXI. R. A. 3' 28- ; Decl. o'* 3' N. Struve, 99; HI. 45; Double; large, white; small, blue; 7th and 12th magni- tudes ; small star is very faint, but is rendered decidedly more distinct by a slight illumination. Blackman-street ; December 20, 1823 ; Five-feet Equatorial Position = 46° 37' sp I 5 Obs. Diff. = 4° C7' ) „ , ,.^ , Distance = s".67S | 5 Obs. Diff. = 1". 1 36 j Extremely difficult. Blackman-street ; January 29, 1824 ; Seven-feet Equatorial. 7th and 12th magnitudes. Position = 42*> 48' *p I 5 Obs. I Diff. = o<> 40' ) , .^ Distance = f.g^g \ 5 Obs. | Diff. = i".034 5 Extremely difficult. Passy ; February 5, 1825 ; Seven-feet Equatorial/ \ 7th and 12th magnitudes. Position = 44® 40 sp. Single measure. Extremely difficult. Night is suddenly become cloudy, not a star visible. / 40 Mr. South's observations of the apparent distances 'N^. CCDGCXXXI. continued. Mean Result. Position 44° 42' sp ; Epoch 1824.38 ; Distance 5".8i2 ; Epoch 1824.02. The angle of 1781 (35" 33' sp), is declared in the MS. ob- servation to be too small by 6** or S° ; and if we suppose the mean (7°) to be the actual error, the corrected angle 42** 33' agrees well enough with the present ; so that no change need be presumed in this star. (H^) No. CCCCXXXII. R. A. s"" 29'" ; Decl. 33° 32' N. Struve, 100 ; II. 52 ; A vei^ riefat double star • equal ; each 8^ magnitude. : ?,.[ .Ill : (>P ^3.''n}>vr?. Blackman -Street ; December 20, 1823 ; Five-feet Equatorial. Position = 14° 6' np or «/| 5 Obs. DifF. = o<> 57' 7 t^;^-,,!. Distance = 3".6i6 | 5 Obs. DifF. = o".4ii j ^^^^""• Night very fine. r .rr; Blackman-strect ; December 29, 1823 ; Seven-feet Equatorial. Equal ; each of the 9th magnitude. Position r: 13* 22' sftknp \ '5 Ohs. Diff. = 0° 45' 7 Pistance = 3''.284 J 5 Obs. DifF. =: o".3i2 j ..... .'"ih.Mean Result. Position 13° 44' sf or np ; Distance 3".4f5o ; Epoch 1823.98. The position of 1783, 8° 24' np, is called a small angle. It is doubtful therefore whether to ascribe the apparent motion of + 5° 20', or + o°.i3o per annum to a real change in the Stars, or to error of observation. (H.) , and positions 0/458 double and triple stars, &c. 41 No. CCCCXXXIII. R. A. 3^ 30"* ; Decl. 28^ 1 1' N. Nova ; or 145.23 ; Double ; 8th and 81- magnitudes ; small, blue. Passy ; November 25, 1824 : Seven-feet Equatorial. Position = 64° 45' sp I 5 Obs. I DifF. = 2® 18' 7 Distance = 7". 196 I 5 Obs. | DifF. 1= o".769 3 Passy ; December 5, 1824 ; Seven-feet Equatorial. 9th and 9^ magnitudes. Position =66° 2 i'«p c Obs. DifF. = 3° o' Kt- u^ • -. k-j Distance rz/^aos 5 Obs. DifF. =; l".iS4 i ^^^^* '' ''"'y ^*^- The evening being much more favourable, the following measures were procured. Position = 64° z''sp 5 Obs. Diff. = 3" 4' \ Distance = 7".579 5 Obs. DifF. = o".4s6 ( Mean Result. Position 65" 3' sp (15 Obs. ) ; Distance 7".S26 (15 Obs.); Epoch 1824.91* No. CCCCXXXIV. R. A. 3^ 32'" ; Decl. 37° 48' N. Struve, 102 ; Hist. Gael. 122 ; Double ; large, white ; small, blue ; 8th and 9th magnitudes. Blackman-street ; December 20, 1823 ; Five-feet Equatorial. Position =: o° 56' nf 7 Obs. DifF. =;; 0° 58' ) <,. , Distance = 28<686 | 5 Obs. DifF. =z o".885 } ^'^eaay. These measures may be a little suspicious, the night having become very hazy ; the small star during the observations, was extremely faint. Blackman-street ; January 27, 1824 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 10 49' n/ 1 5 Obs. I DifF. = i** 20' ) Distance= 28".2i3 I 6 0bs. I DifF. = i".i3o5 Mean Result. Position 1° 33' nf; Distance 28".428 ; Epoch 1824.00. MDCCCXXVI. g 4i Mr. South' s observations of the apparent distances No. CCCCXXXV. R. A. 3^ 35"^ ; Decl. 40° 55' N. Struve, 103 ; Hist. Csel. 137 ; Double; 9th and 10th magnitudes ; bear but a very feeble ,^,; illumination. Passy ; December 7, 1824 ; Seven-feet Equatorial. Position = 44° 28' nf Distance = 9". 877 c Obs. Diff. = 1° 8' ) ^r j-a: 1. S Obs. DifF. = i".i30 J ^^"y ^^®'^"^*- Passy ; December 10^ 1824 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 44° 7' «/| c Obs. I DifF. = 2« 35' ) ,, ^ , ,.« ,^ Distance = J^.858 "^ | 5 Obs. | DifF. =: orSg? l^^'^'^'^'^y ^^®^"^^- Mean Result. Position 44** 18' nf; Distance 9". 867; Epoch 1824.94. No. CCCCXXXVI. R. A. 3^ 35" ; Decl. 56^ 3i' N. Struve, 104 ; Hist. Gael. 371 ; Double ; 7th and 8th magnitudes. Blackman-street ; December 20, 1823 ; Five-feet Equatorial. Position = 15° 50' nf\ 5 Obs. | DifF. = 0° 41'. Night bad. Observations of distance impracticable. Blackman-street ; December 22, 1823 ; Five-feet Equatorial. 7th and 8th magnitudes. Position = 16° zi' nf Distance = 58 '.357 c Obs. 1 DifF. =: 1° s' } ri ,. .^ 5 Obs. I DifF. = i".568l Unsteady. Blackman-street ; December 30, 1823 ; Seven-feet Equatorial. 7th arid 8th magnitudes. ' Position = is°56'n/| 5 Obs. Diff- = 0° 3 2' ? Unsteady Distance = 57"'OSS I 5 ^^s- DifF. = o".529 j '* The distances do not accord so well as might be expected ; a circumstance which, by the non-existence of other observations, appears to have been overlooked. Mean Result. Position 16° 2' wf(i5 Obs.) ; Epoch 1823.98 ; Distance 57^.706 (10 Obs.) ; Epoch 1823.99. and positions of ^s^ double and triple stars y &c, 43 No. CCCCXXXVII. R. A. 3^ 36^; Decl. 23- 27' N. Struve, 105 ; 'Double ; 9th and 10th magnitudes. Blackman-street ; December 27, 1823; Five- feet Equatorial. Position = 29° 48' */ I 5 Obs. 1 DifF. = o° 3/ } Distance = 34''.595 j 5 Obs. | DifF. = o".7695 Blackman-street ; January 2, 1824 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 29® 38' sf I 5 Obs. Diff. = i«» o' > ) Distance = 34".493 | 2 Obs. DifF. = o".793 j No more measures can be obtained j not a star visible. Mean Result. Position 29° 43' sf; Distance :34".666 ; Epoch 1823.99. No. CCCCXXXVIII. R. A. s^ 37" ; Decl. 23*' 32' N. Alcyone ; Struve, 106. Quadruple ; A 4th, B 6th, C 8th, and D of the 9th magnitudes. Measures of A B. Blackman-street ; December 27, 1823 ; Five-feet Equatorial. Position = 18° 57' up I 6 Obs. DifF. = o° 31' Distance = i' 56".7i8 | 6 Obs. DifF. = i".358 Rather difficult. Just as these measures were begun, the night became suddenly hazy, so that A seemed of the 6th, and B of the loth magnitudes. Blackman-street ; December 31, 1823 ; Seven-feet Equatorial. 4th and 6th magnitudes. Position = 1 8° 28' np I 5 Obs. DifF. = 0° 14' | o,.- ru,^„„. Distance - 1' 56".496 | 5 Obs. DifF. = o".7695 ^atisractory. Measures of B C. Blackman-street ; December 27, 1823 ; Five-feet Equatorial. 6th and 8th magnitudes. ition = 74" 10' np I 5 Obs. I DifF. = 0° 23' ) tance= i' 25".36o | 5 Obs. | Diff. = i".29SS Position Distance 44 Mr. South' s observations of the apparent distances No. CCCCXXXVIII. continued. Blackman-street ; December 31, 1823; Seven-feet Equatorial. 7th and 10th magnitudes. Distance = i' z^".^^^ \ 5 Obs. | Diff. = i".250. Very hazy. The small star is extremely faint. Passy ; February 5, 1825 ; Seven-feet Equatorial. 6th and 8th magnitudes. Position = 74° 7' np \ $ Obs. ] DifF. == o" 30' ; Measures of B D. Blackman-street ; December 27, 1823 ; Five-feet Equatorial. 6th and 9th magnitudes. Position = sr 49' np \ 5 Obs. ( Diff. = 1° n' \ R^^her difficult. Distance r= 1' 14". 300 | 5 Obs. | Diff. = i'.S79i Evening unfavourable ; small star extremely faint. Blackman-street ; December 31, 1823 ; Seven-feet Equatorial. 6th and 10th, or 11th magnitudes. Position = 33"" S9'^P\S ^hs. Diff. =: 1° 15' 1 r^jn;...,. Distance = 1' 15". 072 5 5 Obs. Diff. = o".84i 5 ^^n^cuit. Night hazy ; small star will bear only a very feeble illumination. Meaii Result. of A B Position 18^ 42' np ; Distance 1' 56". 607 ; Epoch 1824.00. of BC. Position 74f°S'np; Epoch 1824.36; Distance i'25".640 ; Epoch 1824.00. of BD. Position 33° 54' np ; Distance 1' 14".686; Epoch 1824.00. and positions of ^^s^ double and triple stars y &c, 45 No. CCCCXXXIX. R. A. 3^ 38" ; Decl. lo** 35' N. 30 Tauri ; Struve, 107 ; III. 66. Double ; 5th and 12th magnitudes ; small star, blue, and very faint, but is rendered more distinct by a slight illumination. Passy ; December 22, 1824 ; Seven-feet Equatorial. Position = 31® 32' nf Distance ^z 9".79i 7 0bs. S Obs. Diffl = o''.6o'i 1 Excessively difficult. I have often in England, and frequently since my abode here, attempted to observe this double star, but till now alway unsuccessfully. The sky is nearly ob- scured by clouds, but the stars visible in the openings between the clouds are remarkably brilliant ; they also pass through the field of the telescope extremely steadily: yet the wind is tremendously high. NotA^ithstanding these favourable circumstances the measures are attended with so much difficulty, that those of dis- tance may perhaps be liable to an error of one, or even of two seconds. Passy ; December 23, 1824 ; Seven-feet Equatorial. 5th and I2th magnitudes. Position = 30° 57' nf Distance z= 9"-944- 7 Obs. Diff. = 2° S' } ^ • 1 J-n; 1^ 5 Obs. DifF. = o''.769 \ Excessively difficult. The small star is blue, and is invisible without slight illumination ; night remark ably favourable for difficult observations. Mean Result. Position 31° 14' w/(i4 Obs.); Distance 9".867 ; Epoch 1824.98. A measure in 1783, which gives the position 17** 15' nf, can have no reliance placed on it, being contradicted by an estimation which makes it 40** or 45° ; so that no conclusion respecting the motion or rest of this star can be formed. (H.) 4f6 Mr. South' s dbservations of the apparent distances No. CCCCCXL. R. A. 3^ 43" ; Decl. 50° 10' N. , 43 Persei; Struve, 109; V. 41 • Double; 5th and 12th, or i5tli magnitudes; sniall, blue. Passy ; December 29, 1824 ; Seven-feet Equatorial. Position = 50° S3' nf\ 5 01?s. I piff. = ,« 4^', ) Distance = /i6".626 | 5 Obs. | Diff;='6":8i75 ^®^ ^^^^^^t Measiires^of considerable difficulty; the small star under a very sUgKt illumination becomes invisible. Palsf i "Jatifery 2, 1825 ; Seveil-feet Equatorial. i:x9 .qoaH3i.: ^th and 15th magnitudes. ^^^ ^^^^ ■?bsit!<3fe r: 60° 20' »/; a single observation. ExfceSsiVely difficult. Passy ; January 17, 1825 ; Seven-feet Equatorial. 5th and 12th, or 15th magnitudes. i r. ■■ Position Distance ition = 57° 47' nf\ Single Observation) gx-essivelv difficult tance = i' if.gjS \ Single Observatiori 5 ^^^essiveiy aimcuit. The dew is so rapidly deposited on the exterior and interior surfaces of the object-glass, that the small star does not continue visible sufficiently long, for mea- sures of accuracy to be procured. The night is particularly fine. Mean Result, Position 59° S9' «/(? Obs.) ; Epoch 1825.01 ; Distance 1' i6".9S4 (6 0bs. ); Epoch 1825.02. No measures are given by Sir W. H. of this star. ( H. ) and positions of 458 double and triple stars, &czy 47. No. CCCCXLI. R. A. 3*^ 43°* ; Decl. 31° 20' N. 5" Persei ;. Struve, 108 ; VI. 96. Quadruple; A 4th, B 12th, C 15th, and D of the 13th mag- nitudes: all south p^,^ceding. B is decidedly blue ; bears a much better illumination than C or D ; an|i D b,eaj:i?, more than C. Measures of A B. Passy ; December 22, 1824 ; Seven-feet Equatorial. Position = 65* 47' 5p I 5 Obs. ^'"^ — -° --' ^ ^•^ Distance = 12". 825 j 5 Obs. S^f = 3>°'l Difficult. DifF. = o".577> This star B seems to have escaped the observations of Sir William Herschel, a circumstance which is rather singular, seeing that it is brighter than either of the more distant stars, whose situations relatively to ( have been determined by him.— Is the star B variable in point of lustre ? The stars between the clouds are magni- ficently bright, and are unusually steady, although the wind, which during the last thirty-six hours has been tremendously high, threatens every moment to carry away the roof of the observatory. The shutters are only separated from each other by a space equal to the diameter of the object end of the telescope. Passy ; December 23, 1824 ; Seven-feet Equatorial. 4th and 12th magnitudes. Position 640 S3' ^i' I 5 Obs. I DifF. = 1° 27' ] Verv difficult Distance I3".767 1 5 Obs. | DifF. = o".72i S ^^ tumcult. Night very fine, but of A C no measures can be procured; and these of A B just obtained were attended with much greater difficulty than were those of last night ; should therefore the two sets differ, those of last night must have the preference. Passy ; January 19, 1825 ; Seven-feet Equatorial. 4th and 12th magnitudes. Position = 64° 33' «;> I 6 Obs. | DifF. = z^ 45'. Very difficult. To night I should certainly say that the nearest star B was not so distinct with- out illumination as either of the more distant stars, nor does it bear illumination so wqII as the distant star D ; but still allows much more of it than C. Are any of the group variable ? The angle of position of A B was this evening gotten with consi- derable difficulty. The night is very fine. 48 Mr, South's observations of the apparent distances T No. CCCCXLI. continued. Measures of A C. Passy ; December 22, 1824 ; Seven-feet Equatorial. 4th and 15th magnitudes. Position = 71'' ic' sp I c Obs. I DifF. = i* 57' ) ^^ ^ , ..«. ,^ Distance = \' zs/'.iiS \ 5 Obs. | DifF. = i".202 J Extremely difficult. Night very clondy : these observations gotten by availing myself of the rapid motion of the clouds, which now and then presents the stars to view ; when visible they are unusually brilliant, and pass through the field as steadily as possible ; to obtain these measures I have not quitted the observing chair during the last hour, nor do I deem the time ill-spent : except under very unusual circumstances, no ob- servations of this pair of stars can reasonably be expected with this instrument. Passy; December 29, 1824 ; Seven-feet Equatorial. 4th and 20th magnitudes. Position = 72*5' sp \ 3 Obs. | DifF. = i*» 38'. Excessively difficult. Measures of distance impracticable ; and the night is become so unfavourable, that more observations of position cannot be gotten : yet measures of A B and A D might be procured with facility. Passy ; January 19, 1825 ; Seven-feet Equatorial. 4th and 15th magnitudes. Position = 700 4,z'sp I 5 Obs. I Diff. = i« 20' J Excessively difficult. Distance = 1 23".632 j 5 Obs. \ Diff. = i".oio3 ' Night very fine. Measures of A D. Passy ; December 22, 1824 ; Seven-feet Equatorial, 4th and 13th magnitudes. Position = 85° ^6' sp\j Obs. Distances i' 59". 461 j 5 Obs. Sffi^Ss;";}^^^^*-"- A B are more easily observed than A D, and A D than A C ; but all present con- siderable difficulties, and measures of them with this instrument will never be procured, except under the most favourable circumstances. and positions of 4/5^ double and triple stars, &c. 49 No. CCCCXLI. continued. Passy ; December 23, 1824 ; Seven-feet Equatorial. 4th and 14th magnitudes. Position = 84* 58' *;> ] 7 Obs. Distance = 1' 58".682 j 7 Obs. DifF. = 1° 58' DifF. = i".25o} Excessively difficult. The night is very fine, but no measures of A C can be obtained j and these of A D were gotten with much greater difficulty, than were last night's observations. Mean Result. of A B. Position 6s° 2' sp (16 Obs) ; Epoch 1825.00 ; Distance 13'' 296; Epoch 1824.98. of AC. Position 71° 14' sp (13 Obs.) ; Distance 1' 24".379 ; Epoch 1825.01. of AD. Position 85° 27' sp ; Distance 1' 59".07i ; Epoch 1824.98. On the 22nd January, 1783, the position of A C was 66^ 36' sp, differing — 4° 38' from the present angle. Ac- cording to PiAzzi this star has a proper motion of — o".i4 per annum in R. A. amounting to nearly — 6" in 42 years. If this be confined to the large star, an apparent relative motion of the two stars should arise in the direction, and nearly to the amount actually observed. (H.) No. CCCCXLIL R. A. 3^ 50- ; Decl. 22« 41' N. Struve, lis; P. III. 213 ; Hist. Gael. 196. Double ; large, white ; small, blue ; 8th and 8|- magnitudes. Blackman-street ; December 22, 1823; Five-feet Equatorial. Position = 37° 40' sf Distance =: 7". 080 5 Obs. 5 Obs. Sffill-^Hl^'^^""- Blackman-street ; December 29, 1823 ; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 37° 42' sf 5 Obs. DifF. z= !<> 52' ) Unsteadv Distance = 7".3i4 ) 6 Obs. DifF. = i".202 ] Unsteady, Mean Result. Position 37° 41' sf'. Distance 7^.208 ; Epoch 1823.98, MDCCCXXVI. h 50 Mr. South' s observations of the apparent distances No. CCCCXLIII. R. A. 3^ 57" ; Decl. 13° 54' N. Nova ; Double ; 9th and 10th magnitudes : a star C of the 5th mag- nitude precedes it to the north. Measures of A B. Passy ; February 9, 1825 ; Seven-feet Equatorial. Position = 23° 56' sf I 5 Obs. I DifF. = 2° o' ) r)5ffir,i1t Distance = 44".o87 | 5 Obs. | DifF. = ©".793 ] ^^^^uit. Passy ; February 10, 1825 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position 2 ° s i' ./ 1 5 Obs. Diff. = 0° 47' ) y jigj 1 Distance 44".337 | 5 Obs. [ DifF. = o".9i3 ] ^^^ dimcult. The fog is very troublesome. Measures of A C. Passy ; February 10, 1825 ; Seven-feet Equatorial. 9th and 5th magnitudes. Position = 31° 11' np Distance = 3' i'.gog 5 Obs. 5 Obs. DifF. = 0° 32' 1 T, , , , ^ . DifF. = i".o82 \ Tolerably steady. The star C preceding A to the north. Passy ; February 10, 1825 ; Portable Transit.* Observed R. A. of the star A = 3'' 56' 44".9i. Mean Result. of AB. Position 23'' 53' 5/; Distance 44".2 12 ; Epoch 1825.10. of AC. 3i°ii' np; 3' i"-909; Epoch 1825.10. • My Troughton's Seven-feet Transit, to which reference was occasionally made in the former Memoir, being, on account of its bulk, ill calculated for a tra- velling companion, Mr. Simms was requested to construct me one that should be more appropriate ; and as it fully answers the purpose for which it was designed, a brief description of it may not prove altogether uninteresting to the travelling Astronomer. The centre piece of this instrument is spheroidal : the length of the horizontal or transverse axis, including the pivots, is 28 inches: on one end of this axis is a circle of 9.9 inches diameter, having a ring of silver soldered to its circumference, on which the dividing lines are drawn ; the circle is provided with a level and two ver- niers ; the scale of the former reading to 10 seconds, the latter to minutes only ; it is intended solely as a finder, but will give the apparent altitude of a celestial object ac- curate to one minute. The tubes of the telescope are conical, screw into the centre- piece, and may be removed from it at pleasure, as may be also the circle from the and positions of 4;SS double and triple stars, ^c. 51 No. CCCCXLIV. R. A. 3^ 58' ; Decl. 22« 38' N. Nova; Double ; 9th and 9^ magnitudes. Passy ; October 16, 1825 ; Seven-feet Equatorial. Diff! = o«^^2 1 Extremely difficult. Position = 84° %' sp Distance = 6". 301 5 Obs. 5 Obs. Neither star bears sufficient illumination. Night foggy. Between this night and the 22nd of October, when the observatory at Passy was broken up, unfavourableness of the weather prevented me getting a second series of observations. axis ; the cones however of the horizontal axis being firmly soldered and pinned to a shoulder projecting from the centre-piece, are not separable from it : the level of the axis is supplied with a silver scale, each division of which is equivalent to one second. In the focus of the object-glass are seven equi-distant wires, the equatorial interval between any two of them being about 20 seconds of time : on each side of the meridian wire, and at equal distances from it, are two others, so placed that the pole star shall pass from it to either of them in two minutes, for a purpose explained in the Memoirs of the Astronomical Society (vide Vol. I. page 238) ; applicable to each side plate, is an apparatus for regulating the quantity of light projected from the lamp upon the wires. The side plates are similar to those belonging to my Four-feet Transit Circle, and which (I believe) were described in Rees's Encyclo- paedia, when the instrument was the property of Mr. Groombridge. A second level for the horizontal axis, a spare one for the altitude circle, and a second wire- plate furnished with spiders' lines are at hand, and are ready for immediate use, should accident sustained by any of the first set, render them unfit for service— a reserve which no traveller should neglect ; lest also any of the screws by which the various parts of the instrument are connected should be lost, a few additional ones placed in the box are not, (as I have found by experience), without their use. The object-glass was made by Mr. Tulley, and originally belonged to the Westbury Circle : its clear aperture is 2.7 inches, its focal length is 43 inches; with a magnifying power of 300 it defines a Lyrae, Arcturus and Aldebaran, perfectly sharp and round; separates very distinctly the close stars of yLeonis, t Bootis, and ^Orionis; whilst with 150 (the commonly used power) under favourable circum- stances, the small star south preceding Polaris, is sufficiently visible to enable the observer to take its transit, with considerable precision. The instrument is mounted on stone piers, and has retained its meridian position extremely well ; fifteen months' experience has shown, that whilst the maximum error, to which the mean of a single series of observations of any star south of the zenith of my observatory, does not exceed 4-tenths of a second, often, very often, the result of a single set will not deviate 2-tenths from the true right ascension. When the pole star is steady, its transit over the wire may be determined to one second. Thus much for its utility. As for its portability : the transverse axis, the telescope tubes, and the altitude circle, are included in a box 29 inches long, 14 inches broad, and 6| inches deep. The three levels, the spare wire-plate, the light regulating apparatus, the lamp, &c. are lodged in a case 27^ inches in length, i\\ in breadth, and 3! in depth. The side plates, with their appendages of nuts, screws, &c. are contained in a box 13I inches long, y\ inches broad, and 7^ inches deep; and the tout ensemble is well accom- modated under the seat of my travelling carriage. (The measures are all exterior.) . Passy; October 2Z, 1S25. 5s Mn South' s observations of the apparent distances No. CCCCXLV. R. A. ^^ 7" ; Decl. 49° 50' N. Struve, 117; Triple ; A 7t, B 8th, and C of the 10th magnitudes. Measures of A B. Blackman-street ; December 9, 1823 ; Five-feet Equatorial. Position r= 56" 36' np I 5 Obs. [ DifF. = 1° 2' 7 Distance = 1' is"-°\7 I 5 ^^s. | Diff. = i".3S8 j BlackmaQ->street ; December 29, 1823 ; Seven-feet Equatorial. 7i and 8th magnitudes. Position := 56° $1' np [5 Obs. DifF. = o'* 35' I Distance =: i' is"'3H 1 ^ Obs. DifF. = o".84i 3 Measures of A C. Blackman-street ; December 9, 1823 ; Five-feet Equatorial. 7h and 10th magnitudes. Position zz 10° 26' s p Distance =: 2' 29".634 3 Obs. 3 Obs. DifF. =0° 10' 1^ . , ,.^ , DifF. = 3".ooo S ^^cessively difficult. These results are rather suspicious, the small star is so extremely obscure. Blackman-street ; December 29, 1823 ; Seven-feet Equatorial. 7h and 12th magnitudes. Position = 9° 47' *p I 3 Obs. ( DifF. = 0° 20' ) „ ^ , ..^ . Distance = 2' 27''.974 | 3 Obs. | DifF. = ©".649 } Extremely difficult. Passy ; February 6, 1825 ; Seven-feet Equatorial. 7h and 11th magnitudes. Position = ,0° o; sp I 2 Obs. I Diff. = 0° 20' ) Extremely difficult. Distances: 2' z%".tzo \ 5 Obs. | Diff. = ©".889 ) Mean Result. Of A B. Position ^6"" 33' np ; Distance 1' i5".22o ; Epoch 1823.97. Of A C. Position 10° i sp ; Distance 2' 28". 720 ; Epoch 1824.34. and positions of4>58 double and triple stars ^ &c. 53 No. CCCCXLVI. R. A. 4^ 7" ; Decl. 7° 65' S. 40, Eridani ; Struve, 116 ; Double ; 6th and 10th magnitudes ; small, blue. Passy ; December 10, 1824 ; Seven-feet Equatorial. Position = 180 x8' ./I 7 Obs. I DifF. = i° i6' ? E^.^ssively difficult. Distance =: i' 24". 697 ± ; Single measure 3 ^ No satisfactory measures of distance can be procured ; the deposition of mois- ture upon the object-glass is so considerable, notwithstanding a tube* twelve inches long is adapted to the object-end of the telescope, that I am obliged to wipe it every few minutes. The stars, even those of low altitude, are unusually steady : were it not for the annoyance of the dew, stars presenting almost any degree of difficulty might be well observed to night. Thermometer stands at 24°. The instrument is covered with hoar frost. Passy ; December 22, 1824 ; Seven-feet Equatorial. 5th, and 9th or 10th magnitudes. Position = 17° 34' */ Distances i' 24". 178 5 Obs. 5^5 = °?, 3?; I On the meridian. 5 Obs. I DiflF. = I ".082 Measures extremely difficult. Stars so remarkably steady, that they may be kept bisected by the wire almost as long as I please. The wind is blowing a perfect hurricane ; and fearing that a perseverance in observing, may occasion the destruc- tion of the observatory, I am obliged, although reluctantly, to discontinue working. Scarcely ever do I remember to have seen such opportunities for making delicate observations, as the chasms between transient clouds have presented this evening. Passy ; December 23, 1824 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position — 17° 45' */. Single observation. Excessively difficult. The night suddenly has become bad ; the small star is no longer visible. Passy ; January 28, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position =: 17° 56' 5/ Distance = i'' 25". 279 D^:^ll%]^^''''^'^y^^^'''^'' 5 Obs. 5 Obs. Mean Result. Position 17° 58' 5/ ( 18 Obs.) ; Epoch 1824.99 ; Distance 1' 24".726 (11 Obs.) ; Epoch 1825.00. * The tube first employed for this purpose was made of pasteboard : the dew however was frequently so copious that its figure became deranged, and it could with difficulty be re-applied to the object-end of the telescope. Under these cir- cumstances, the veneered deal of which the English hat-box is constructed, aflForded a material not liable to this inconvenience — its pliability rendered it easy to add one cylinder to another, so as to form a tube of any desired length, its weight at the same time very slightly disturbing the equilibrium of the telescope. 54 Mr, South's observations oj the apparent distances No. CCCCXLVII. R. A. 4^ 13" ; Decl. 33° 5s' N. Struve, 124; IV. 72 ; Double ; Si- and 9th magnitudes. Passy ; December 10, 1824 ; Seven-feet Equatorial. Position = 290 48' nf Distance = 2o".oio 5 Obs. I DifF. = 1° 48' \ 5 Obs. I DifF. = i".2265 Passy ; December 22, 1824 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 29° 51' «/ Distance = i9".72i 5 Obs. 5 Obs. F. = lo I' I F.= l".202 5 DiiF. = lo I' DifF. The small star is decidedly blue. Mean Result. Position 29° 49' nf; Distance 19".865 ; Epoch 1824.96. The measures of 1783 were, Position 27° 24' nf\ Dis- tance 16". S 6 ; the former differing but little from the pre- sent ; the latter presenting an increase of 3".oi5, being more than should be expected on a total of 1 7" only, (H.) No. CCCCXLVIII. R. A. 4M8™ ; Decl. 29° 57' N. Struve, 124; Hist. Casl. 136; Double ; 8th and 10th magnitudes ; small, blue. Blackman-street ; December 22, 1823 ; Five-feet Equatorial. Position = 550 57' nf I 5 Obs. I DifF. = 1° 16' \ " ' " =o".2845 Distance = I5".276 | 5 Obs. | Diff. Blackman-street ; December 30, 1823 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 55° 29' n/ 1 5 Obs. I DifF. = i* 15' ^ Distances 1 5 ".2 3 2 | 5 Obs. | DifF. = o".4565 Mean Result. Position SS"" 43' nf; Distance 15^254 ; Epoch 1823.99. and positions of 4:6^ double and triple stars ^ &c. 56 No. CCCCXLIX. R. A. 4^ i8- ; Decl. 9° 4i' N. Struve, 126 ; IV. 75. Double ; 10th and 12th, or 15th magnitudes. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position =: 66° 30' sf; single observation. Excessively diificult. These stars are so very faint, that measures entitled to any confidence cannot be obtained. Passy ; January 6, 1825 ; Seven-feet Equatorial, llth and 15th magnitudes. Position = 650 56' sf I 5 Obs. DifF. 3«> ^of ) <, , Distance = zz".6oz ± \ 2 Obs. DifF. z".zZ^. ] ^^^ady. Observed when on the meridian. Night very fine ; but the measures, particu- larly those of distance, are so excessively difiicult, that I fear they must be consi- dered as liable to some inaccuracy. Passy ; February 10, 1825 ; Seven-feet Equatorial. llth and 15th magnitudes. Position = 69° 16' 5/ I 5 Obs. I Diff. = 2<» 55' > „ . , ,.«. ,^ Distance = 23".496 ± | i Obs. | DifF. = _ii- ] Excessively difficult. Measures little better than guesses. The fog is now become so dense, that to persevere in observing, is impossible. Mean Result. Position 67° 30' sj (ii Obs.) ; Epoch 1825.04 ; Distance 22",90o+(3 Obs.); Epoch 1825.05. The angle, Feb. 16, 1783, was 61** 36' sf, differing 5° 34' from the present, being a change of +0^.132 per annum. The distance at the period above specified w^as 22".6o, agree- ing very exactly with the present. Future observations must decide on the reality of the motion here indicated. (H.) 56 Mr. South's observations of the apparent distances No. CCCCL. R. A. 4^ 19" ; Decl. 39° 35' N. 145, 24, or Nova? Double ; 7 ^ and 8th magnitudes. Passy ; December 26, 1824 ; Seven-feet Equatorial. Position r= 25* 28' sf Distance z= 9 .652 5 Obs. ( DifF. =z I" 21' ) 5 Obs. DifF. = ©".505 j Passy ; December 29, 1824 ; Seven-feet Equatorial. 7^ and 8th magnitudes. Position = 24° 36' sf\ 5 Obs. DifF. = 0° 52' 7 Distance = 9".504 | 5 Obs. DifF. = o".74.5 1 • • * • • Passy; February 11, 1825 ; Portable Transit. Observed R. A. of the larger star = 4^^ 19' 29".74. Mean Result. Position 25° 2' ^/4 Distance 9".578; Epoch 1824.99. CCCCLI. R. A. 4"^ 23™ ; Decl. 47° s' N. Nova ; Double ; 7y and 8th magnitudes. Passy; February 9, 1825 ; Seven-feet Equatorial. 5 Obs. I DifF. = 0° 48' 7 5 Obs. I DifF. = o".6oi j Passy ; February 11, 1825 ; Seven-feet Equatorial. 7th and 71 magnitudes. Position = 74® 21' «;> 1 5 Obs. DifF. = 0° 48' 7 Distance = i' ©".357 \ 5 Obs. DifF. =: o".505 j Passy ; Februaiy 11, 1825 ; Portable Transit. Qbserved R. A, of the larger star = 4*^ 23' 26".o8. Mean Result. Position '74<°tS'sp; Distance i'o".454; Epoch 1825.10. Position =: 74° 16' sp Distance = i' o".55i and positions of ^58 double and triple stars, ^c. 57 No. CCCCLII. R. A. 4^^ 26™ ; Decl. 16° 8' N. Aldebaran ; Struve, 129 ; VI. 66. Double ; 1st and 20th magnitudes. Passy ; January 16, 1825 ; Seven-feet Equatorial. Position = 53<» zy' nf-±. | 4 Obs. | DifF. =: 1" 12'. Excessively difficult. Distance about a minute and a half by estimation ; observations of distance cannot be procured, the small star being so excessively faint, that it becomes invi- sible under the slightest illumination. The position here given may be liable to an error of one, or two degrees. Passy ; January 19, 1825 ; Seven-feet Equatorial. 1st and 20th magnitudes. Position = 54<» 32' w/± | 2 Obs. | Diff. = o'' 36'. Excessively difficult. The small star will not bear even the slightest illumination. The night being unusually favourable, I was very anxions to procure, if possible, measures entitled to confidence; and finding all attempts with a power of 179 ineffectual, I applied 273 : no advantage however was gained by the change of eye-piece. The observa- tions of position must, I fear, be regarded with distrust, and any of distance with this instrument are altogether impracticable. Mean Result. Position 53° 49' nf±(6 Obs.); Distance about one minute and a half by estimation; Epoch 1825.04. In 1781 the angle was 52° 58' nf. In 1802 it was mea- sured at 54° 8' nf: the present is nearly a mean between them. It is clear therefore that no very sensible motion can exist in this star. According to the proper motions set down in PiAzzi's catalogue, the angle of position should be liable to a slow change in the direction np sf or ^^, amounting how- ever to a quantity hardly cognizable in 40 years. (H.) MDCCCXXVI. i 58 Mr, South' s observations of the apparent distances No. CCCCLIII. R. A. 4'* 27" ; Decl. 10° 5' S. Struve, 131 ; III. 100. Double ; 7th and 8th magnitudes. Blackman-street ; December 13, 1823 ; Five-feet Equatorial. Position = 11" 36' sp \ 5 Obs. I DifF. = j® 48' \ Distance = 13".637 \ 6 Obs. | pifF. = i".26^ 5 Blackman-street ; January 29, 1824 ; Seven-feet Equatorial, ^th and 10th magnitudes. Position = 11° 9' *D I 5 Obs. | DifF. = 1° 15' ) r\\ff...,^*■ Distance = if. 662 \ 5 Obs. | DiflF. = 6.769^ Uiflicult. Mean Result. Position 11° sa' sp; Distance 13"- 634 ; Epoch 182401. There seems a sensible change of position in this star. In 1783 (Feb. 19) its angle was 16° 24' sp. The change amounts to 5° 2' in the direction sp w/ or + » i* ^' to + o°.i23 per annum. An increase also of i".7 in distance has hap- pened. As the star is an easy one to measure in favourable w^eather, there is much probability that these changes are owing to real motions. (H.) ■"' ^'^* No. CCCCLIV. R. A. 4'^ s8- ; Decl. 26° ^^ N. Struve, 133; Hist. Csel. 204. Double ; equal ; each of the 8th magnitude. Blackman-street ; December 13, 1823 ; Five-feet Equatorial. Position = 60° 36' nfov sp \ 5 Obs. 1 DifF. = 0° 33' ^ Distance = 3".9 1 3 j 5 Obs. ] DifF. = o".379 ^ Blackman-street ; December 30, 1823 ; Seven-feet Equatorial. Equal ; each of the 8th magnitude. Position = di** 10' sp or w/1 5 Obs. I DifF. = 1° o' 7 Distance = 3".926 | 5 Obs. J Diff. =o"336 3 Mean Result. Position 60° ss' sp ornf; Distance 3"9i9 ; Epoch 1823.97. and positions of 458 double and triple stars ^ ^c. B9 No. CCCCLV. R. A. 4*' 31" ; Decl. 22" 36' N. -"'^Tauri; StRUVE, 134; VL ^y'^^^ Double ; large, white ; small, blue ; 5th and 8^ magnitudes. Blackman-street ; December 27, 1823 ; Five-feet Equatorial. Position = 58° 33' «p j 5 dbs. I DifF. = o° 30' ) Distande =r 1' l"425 f } Obs. | Diff. = o".632 5 Blackman-street ; December 31, 1823 ; Seven-feet Equatorial. 6th and lOth magnitudes. Position = sf 24' *;> I 5 Obs. I Diff. = o^ 55' J Rather difficult. Distance = i' 3 .210 | 5 Obs. | DifF. =0.5775 Night very hazy. The small star is indistinct. Mean Result. Position 58° 28' sp ; Distance i' 2".8i7 ; Epoch 182400. No measures of position are given by Sir W. H. The distance does not seem to have changed. ( H. ) No. CCCCLVI. R. A. 4»^ 32"" ; Decl. o** S5' N. Struve, 135; 11. 81 : Triple ; A 9th, B lith or 12th, and C of the 15th magnitudes. Passy ; January 6, 1825 ; Seven-feet Equatorial. Measures of A B. Position = 56° 44' np I 6 Obs. I DifF. = 2° 14' 1 ,. ,.«. ,^ Distance = 6".494 | 5 Obs. | Diff. = i".6l9 1 ^'"^ '^'^'"^'' Measures of A C. Position zz6° d sp dr ; single observation 7 u • 1 j-m ^^ Distance = I' 44".4i2±; sinlle observation j E«essively difflcult. The star C is so extremely obscure, that accurate measures cannot be procured ; the night is very favourable. ,6o Mr. South's observations of the apparent distances No. CCCCLVI. continued. Passy ; January 19, 1825 ; Seven-feet Equatorial, r Measures of A B. 9th and 12th magnitudes. Position = 56«» i' «p I c Obs. DifF. = o° o' 7 „ • i j-/r i. Distance = 6".^iy | 5 Obs. DifF. = o".505 \ Excessively difficult. I see the small distant star C, but can neither measure its position or distance^ Night fine, ■ '^^^^i^^ J*^i- Mean Result. of A B. Position 56° 24' np (1 1 Obs.); Distance 6."455 ( 10 Obs.) ; Epoch 1825.03. '-\^r of A C. Position 6° o' 5 /> + ; Distance 1^ 4V.412 + : Epoch 1825.01. (Single observations.) The position Jan. 31, 1783, was 51° s6' np, differing 4° 48' from the present. (H.) No. CCCCLVII. R. A. 4^ 44" ; Decl. 1" 34' S. Struve, 138 ; Hist. Gael. 251 ; Double ; nearly equal ; 8t and H^ magnitudes. Blackman-street ; December 9, 1823 ; Five-feet Equatorial. Position = 84° zi np 5 Obs. I DifF. = 0° 24' ) Distance = 41 ".697 5 Obs. | Diff. = o".632) Blackman-street ; January 29, 1824 ; Seven-feet Equatorial. 9th and 91 magnitudes. Position = 820 53' »p 5 Obs. DifF. = 1° 5 \ Distance =:4i".i82 ' ^ Obs. DifF. = i".oio j[ ^i^ictilt. Passy ; March 26, 1825 ; Seven-feet Equatorial. 85 and 9th magnitudes. Position = 83** 48' np I 5 Obs. I Diff. = o° 45' \ Distance = 4i".59i | 5 Obs. DifF. = i".202 j Observed by twilight, without artificial illumination. Mean Result. Position 83° 41' np ; Distance 4 1".490 ; Epoch 1824.42. and positions 0/4,58 double and triple stars y &c. 61 No. CCCCLVIII. R. A. 4^ 44™ ; Decl. 7° 6f N. Struve, 139 ; Hist. Gael. 42 ; Double; qy and 10th magnitudes. Blackman-street ; December 27, 1823 ; Five-feet Equatorial. Position = 73° f sp\ c Obs. I DifF. = i® 30' ) ,, ..^ ,^ Distance= i6".6i8 \ s Obs. | DifF. = o".sos ] "^^"^ ^^^<^"^*- .jl;i:ri Neither star bears a good illuftiination. Blackman-street ; January 29, 1824 ; Seven-feet Equatorial. "^ ' '"^ 9h and 9| magnitudes. Position rr/S** 10' sp I 5 Obs. DifF. = !<> o' ) ,. ,.- ,^ Distance = 17". 2^9 \ 5 Obs. DifF. = i".o345 "^ difficult. iVfe^w Result. Position 73' 8' sp ; Distance i6".93S ; Epoch 1824.03. No. CCCCLIX. R. A. 4^ 47" ; Decl. 60" 11' N. 10, Camelopardali ; Struve, 141 ; VI. 36 ; Double ; r,th and 9th magnitudes ; small, blue. Passy : January 5, 1825 ; Seven-feet Equatorial. Position = 62° 11' *p I 5 Obs. I DifF. = o° 36' 7 Distance= r' 2o".276 I 5 Obs. I DifF. = o".73i I • • . • Passy ; February 6, 1825 ; Seven-feet Equatorial. 5th and 9th magnitudes. Position = 62 25' sp I 5 Obs. DifF. = 0° 37' ) Distance = i' I9".443 | 5 Obs. Diff. = i".s^6 j Mean Result. Positioner** iS' sp ; Distance 1' i9".859 ; Epoch 1825.05. No measures given by Sir W. Herschel of this star. (H.) €^ Mr. South' s observations of the apparent distctnces r No. CCCCLX. R. A. 4*^ 49" ; Decl. i** 23' N. Struve, 145 ; I. 68 ; Double ; equal; each of the 10th magnitude ; a star of the 5th magnitude follows it to the south. Passy ; Janilary 6, 1825 ; Seven-feet Eqaatorial. Diff! = d'lti \ Extremely difficult. Position = 83** \i' sfot np\y Obs. Distance= 2".30i j 5 Obs. Observations made with 179 j a power of 273 was tried, but without any advan- tage. The night is remarkably fine, and the stars are very steady. It freezes hard. Passy; January 17, 1825 ; Seven-feet Eqaatofial. Equal; each of the 10th magnitude. Position = 84** 25' sfov np \ 5 Obs. | DifF. = 5° 30'. Excessively difficult. Of distance no measures can be obtained, in consequence of the rapid depdsition of moisture on each surface of the object-glass. Night very fine; the stars are re- markably brilliant. A slight frost. Passy; February 6, 1825; Seven -feet Equatorial. Equal ; each df the 1 0th magnitude. Distance = 2".83o | 5 Obs. | DifF. =z ©".360. Excessively difficult. The night is become suddenly cloudy ; no more observations can be procured. Mean Result. Position 83° 49' sfot np (12 Obs.) ; Epoch 1825.04 ; Distance 9.". $65 (10 Obs.); Epoch 1825.06. In 1783, January 22, (1783.06), the Position was 84° 54' nf, being a change of 1 1° 1 7' in 42.00 years, in the direction np sf, or retrograde — that is, — 0^.269 per annum. The change is so considerable, as to render it highly probable that this star belongs to the class of binary, or connected stars, and should therefore be assiduously watched. (H.) and positions of^fSB double and triple stars,. ^c, 63 No. CCCCLXI. R. A. 4^ 50°^ ; Decl. 26° 25' N. Struve, 146 ; Double ; 7th and 8|- magnitudes. Passy ; December 5, 1824 ; Seven-feet Equatorial. Position = 68° 33' «/ 1 5 Obs. J DifF. =r 0° 29' I Diff. = i".37o5 Distance= i' iS'.SozJ 5 Obs. Passy ; December 10, 1824 ; Seven-feet Equatorial. 7th and 9th magnitudes. Position = 68° 40' «/ 1 5 Obs. I DifF. = 0° 47' ) 1 5 Obs. I Diff. = o".865 I ■ - . - . , ^7' * Distances i' i8".3Zi j 5 Obs. J Diff. = o".865 The ^Hxall star is blue. Mean Result. od =z nohho^. Position 68° 36' sf; Distance 1' 18". 561 ; Epo3i' 1624.94. No. CCCCLXII. R. A. 4^ 51" ; Decl. 3° 22' N. Struve, 147 ; Hist. Gael. 465. Double ; 6 J and 7th magnitudes. Passy ; December 5, 1824 ; Seven-feet Equatorial. Position = 11° A.' s p c Obs. I Diff. = o° 47' 7 ^ . , • ,. Distance ;=2i".6o/ 5 Obs. | Diff. = o^sfs 1 ^" '^' "''"^^^°' Night not very favourable. Passy ; December 10, 1824 ; Seven-feet Equatorial. 7 th and 8th magnitudes. Position = 9° 45' *jp 5 Obs. Diff. = 0° 51') q. . Distance = 22".423 5 Obs. Diff. = i".202 5 ^«aay. The dew is extremely troublesome. Passy ; February 4, 1825 ; Seven-feet Equatorial. 7th and 8th magnitudes. Position = 10° 30' sp 5 Obs. Diff. = 1° 29' J <;.^,j„ Distances 2i".399 5 Ohs. Diff. = o".74S j ^^^^^Y- Mean Result, Position 10'' 26' 5/) (15 Obs.) ; Distance 2i".8o8 (15 Obs.) ; Epoch 1824.99. 64 Mr. South's observations of the apparent distances No. CCCCLXIII. R. A. 4^ 52"^ ; Decl. ii^Vn. Struve, 149; Double; 7th and 12th magnitudes. Passy ; February 8, ] 825 ; Seven-feet Equatorial. Position =. 60° 39' nf 5 Obs. I DifF. =r i° 29' 1 Excessively difficult Distance = 33".787 ± 3 Obs. | DifF. = 2". 620] excessively aimcuit. The small star scarcely bears the least illumination. The observations of distance deserve probably but little confidence. The night is unfavourable. Passy; February 9, 1825 ; Seven-feet Equatorial, th and 12th magnitudes. Position = 6o°ii'»/ 5 Obs. Diff. = 4° 23' Uxtremely difficult. Distance = 33 .967 5 Obs. DifF. = i ".4433 ^ .. Mean Result. Position 60* 25' nf\ (10 Obs.) ; Distance 33".6o4 (8 Obs.) ; Epoch 1825.10. No. CCCCLXIV. R. A. 4'' 53" ; Decl. 79° o' N. 62 (Bode), Camelopardali ; Struve, 152 ; Double ; 7th and loth magnitudes ; small, blue. Passy ; February 6, 1825 ; Seven-feet Equatorial. Position = 76° 56' np I 5 Obs. | DifF. = o° 13' ) y „ , Distance = 37".29o | 5 Obs. DifF. = o".48i ] ^^^ '*^^^y- Passy ; February 8, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. Position = 75° 50' np Distance = 36".734 5 Obs. 5 Obs. DifF. = 1° 12') DifF. = I ".010 5 The small star is decidedly blue. Mean Result. Position 76° 23' np ; Distance 37*.oi2 ; Epoch 1825.10. and positions 0/4,58 double and triple stars y &c. 65 No. CCCCLXV. R. A. 4" SS'^ ; Decl. i'* so'N. Struve, 150; P. IV. 278. Double ; 7th and 8th magnitudes ; small, blue. Passy ; December 5, 1824 ; Seven-feet Equatorial. Position = 43° I3'«/I 5 Obs. | Diff. = 1° 50' ) Distance = i4''.340 j 5 Obs. | Diff. = o".6oi j • • • • Passy ; December 10, 1824 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 4o<» 16' n/ 1 5 Obs. I Diff. = 2° i' ) Distance = 14".907 | 5 Obs. J Diff. = o".48i 3 • • > • Passy ; January 16, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 41° 36' nf\ 5 Obs. Diff. = 3° 55' \ Distance = i4".o59 | 5 Obs. Diff. =o".3845 • • • • A double star of the 6th class is in the field with this double star : its smaller star has nearly the same right ascension as the larger of the stars here measured. Mean Result. Position 41° 42' nf [15 Obs.) ; Distance 14".435 ( i5 Obs. ) ; Epoch 1824.97. No. CCCCLXVI. R. A. 4^ 57" ; Decl. 21° 27' N. 105 Tauri ; Struve, 155 ; VI. 105. Double ; 7th and 10th magnitudes ; small, blue. Passy ; January 17, 1825 ; Seven-feet Equatorial. Position = 19° 8'*p I c Obs. I Diff. = i° i8' ) ^ ^ i j-o: i* Distance = i V.9+4 I 5 Obs. | Diff = o\62S J Extremely difficult. One hour and a half east of the meridian, at the time of observation. MDCCCXXVI. k ^ Mr. South' s observations of the apparent distances No. CCCCLXVI. continued. Passy ; January 17, 1825 ; Seven»feet Equatorial. 7th and 12th magnitudes. Position as i8° 59' sp I 5 Obs. Distance = i' 5o".o36 | 5 Obs. Diff. T\:ff' _ ," jq5 \ Extremely difficult. Observed when on the meridian : the small star bears only a very feeble illumin- ation. This set of measures was taken inadvertently; I had omitted to note the star as observed, in the earlier part of the evening. Mean Result. Position 19° 3' s p ; Distance 1' 49"-99o ; Epoch 1825.04. Sept. 28,1783. Position iH^'o' sp; Dist. 1' 4i".5, being a change of 1° 3' in position and + 7*- 5 ^^ distance ; but this last quantity, for the reasons already given, cannot be relied on. There is therefore no reason to presume motion in these stars. (H.) No. CCCCLXVII. R. A. 4»^ SQ'^ ; Decl. 31° 5i' N. Nova ; Double ; 9th and 9^ magnitudes. Passy ; October 11, 1825 ; Seven-feet Equatorial. Position = 16° 12' nf c Obs. I Diff. = 3° 12' ) ^ ^ , .-n: u Distance = 4".2ai 5 Obs. | Diff. = o".2i65 Extremely difficuh. Observed when 2 J hours east of the meridian. Night foggy; stars occasionally very faint. Passy; October 16, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Night foggy, and stars so faint, that with i8i they cannot be seen; observed with 157. .il;ioIii ::-iJ ][fg^^ Result. Position 15° 4,0' nf; Distance 4*.57i ; Epoch 1825.78. and positions of 458 double and triple stars , ^c. 67 No. CCCCLXVIII. R. A. 5^ o- ; Decl. 13° 47' N, Struve, 157 ; Hist. Gael. 203. Double ; 9th and 10th magnitudes. Passy ; December 31, 1824 ; Seven-feet Equatorial. Position = 72° 23' sf 5 Obs. I Diff. = 1° 30' \ ,. ..a- . Distance = zf'-SS^ 5 Obs. | DifF. = ,".010 j ^^^^ ^^^*^"1*- These stars bear only a feeble illumination ; but the night is unfavourable. Passy ; January 2, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. Position = 72° 52' «/ s Obs. I DifF. = z° 10' \ ^ • 1 j-n: 1. Distance = z6".%ii 5 Obs. \ DifF. = f'.sij \ Excessively difficult. Mean Result, Position 72** si sf; Distance 27". 183 ; Epoch 1825.00. No. CCCCLXIX. R. A. 5^ 4"^ ; Decl. 2° 38' N. 145.21, or Nova ? Double ; 7th and 10th magnitudes : small, decidedly blue, and bears a good illumination. Passy ; February 12, 1825 : Seven-feet Equatorial. Position = 28°33'«/ Distance = 6", 670 5 9m Diff- =4° 4V I Unsteady. 5 Obs. I DifF. = o".5 77 Passy ; February 17, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. Position = 27° 30' nf Distance =: 7". ^39 5 Obs. 5 Obs. Diff! = o°.697}^^^""'*^^^y' Passy ; February 23, 1825 ; Portable Transit. Observed R. A. of the larger star = ^^ 4' io".83. Mean Result. Position 28° 1' nf; Distance 7".o54 ; Epoch 1825.12. 68> Mr. South' s observations of the apparent distances No.CCCCLXX. R. A. s'^S"'; Decl. 17'40'S. Struve, 161 ; Hist. Csel. 562. Double ; 10th and io|- magnitudes. Passy ; January 17, 1825 ; Seven -feet Equatoria]. Position =: y'^A.j'np I c Obs. DifF. = o°3o' 7 i? ^^ • i j-ie »^ Distance = 48^65/ | 5 Obs. | DifF. = o".;*! r''^''"'^'^^ ^^®*^"^*- Neither star bears sufficient illumination, and the observations of distance maj- perhaps be a little inaccurate. t*assy; Januaiy 19, 1825; Seren-feet Equatorial. 10th and 10^ magnitudes. Position =s 7° 33' nj» Distance = 47".956 cObs. Diflr. = 10 2' 7„ • , j-«. ,. 5 Obs. Diff. = i".443 i Excessively difficult. Mean Result. Position 7° 38' np ; Distance 48".304 ; Epoch 1825.05. No. CCCCLXXI. R. A. 5^ 5™ ; Decl. S3° 9' N. Struve, 162 ; II. 48. Double ; 8^ and 9th magnitudes. Passy ; December 5, 1824 ; Seven-feet Equatorial. Position s= iB° ^' sp Distance = 2".837 5 Obs. 5 Obs. DifF. = 1° 32' ) DifF.=o".553l Passy ; December 22, 1824 ; Seven-feet Equatorial. 8i and 9th magnitudes. Position =z 17° g' sp j 5 Obs. I DifF. z= 3° 10' \ Distance = 2".8o8 | 5 Obs. | Diff. = o''.865 J • • • • Mean Result. Position 17° 37' sp ; Distance 2".822 ; Epoch 1824.95- The position in 1783 was 15" 48' nf, so that there is no reason to suppose any change in this star, as there is so little difference in their magnitudes, that the larger might easily be mistaken for the smaller, and thus 180° difference in posi- tion arise. (H.) and positions 0/4,58 double and triple stars y &c. 69 No. CCCCLXXII. R. A. 5^6^; Decl. 39° 58' N. X Aurigae; Struve, 164 ; V. 22. Triple ; A 5th, B 11th, and C of the 12th magnitudes. Measures of A B. Passy ; February 9, 1825 ; Seven-feet Equatorial. Position = cc**24'n/' 5 Obs. I DifF. iz i°2q' 7 t? ^ _ i j-o: i* Distance = 5' 42^646 5 Obs. | DifF. = i".827 j Extremely difficult. Passy ; February 12, 1825 ; Seven-feet Equatorial. 5th and 11th magnitudes. Position = 55° 25' nf c Obs. i DifF. = 0° 16' ) „ , , ..a- ,^ Distance = i' 41 ''.640 5 Obs. | Diflr. = 2".3s6 J Extremely difficult. The small star to-night will bear but the slightest illumination. North preceding, and at about the same distance, is a star of the 1 5th magni- tude ; but it is so excessively faint, that neither its angle with, or distance from A can be observed ; yet the night is very clear. Measures of A C. Passy ; February 9, 1825 ; Seven- feet Equatorial. 5th and 12th magnitudes. Position = 8° 23' nf \ 2 Obs. | DifF. = 0° 33'. Excessively difficult. The distance I cannot obtain ; the small star C will not bear the slightest illu- mination. The star C is also itself double of the 5 th class ; but although the night is remarkably fine, I cannot get even approximate measures of it. Passy; February 12, 1825 ; Seven-feet Equatorial. 5th and 12th magnitudes. Position = 8» 33' nf Distance = 3' i3".94i 5 Obs. DifF. = o°i8' 1p . , ..«. ,^ S Obs. DifF. = i".o34 \ Excessively difficult. The star C seen double of the 5 th class ; but its small star, which is south pre- ceding, is so very obscure, that my attempts to procure measures of it have been unsuccessful ; yet the night is exceedingly fine. Mean Result. of A B. Position 65° 24' nf; Distance 1' 42".i43- of AC. Position 8° 30' nf(^ Obs.) ; Distance 3'iS".94i (50bs.); Epoch 1825.10.^ Sir W. Herschel has no measures of this star. (H.) . 70 Mr. South' s observations of the apparent distances No. CCCCCLXXIII. R. A. 5^ 10™ ; Decl. 15' 26' S. Struve, 168 ; Hist. Gael. 467. ! - Double; 8th and 10th magnitudes. Passy ; December 31, 1824 ; Seven-feet Equatorial. Position = 32° 50' np \ 5 Obs. | DiflF. = o" 28'. Very difficult. The night is suddenly become bad ; observations of distance impracticable. Passy ; January 25, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position = 34° 13' «p I 5 Obs. Distance = 2o".932 } 5 Obs. Dm.ztlL\^^''''^'^y^'^''^^'' The small star bears only the slightest illumination. Night fine. Passy ; February 5, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position = 35° i' nj9 Distance= 2o".757 5 Obs. 5 Obs. Diff! = o''.84i I Extremely difficult. Mean Result. Position 34° i' np (15 Obs.); Epoch 1825.05. Distance 20''. 844 (10 Obs); Epoch 1825.07. No. CCCCLXXIV. R. A. 5^ 11'^ ; Decl. io« 56' S. Struve, 169 ; Hist. Gael. 313. Double ; 8^ and 9th magnitudes. Passy ; December 5, 1824 ; Seven-feet Equatorial. Position = 1° 35' «j? J 5 Obs. Distance = io".7i3 | 5 Obs. DifF. = 1° 28' \ DifF. =:o".72i5 Passy; December 10, 1824 ; Seven-feet Equatorial. 8| and Qth magnitudes. Position = 3° 5' np Distance = 11". 166 5 Obs. 5 Obs. DifF. = 1° 2c' \ r^ ,. . ,. DifF. = o".72i } ^"^ *^^ meridian. Passy ; February 5, 1825 ; Seven-feet Equatorial. 8^ and 9th magnitudes. Position 3° 47' np \ 5 Obs. | DifF. = 1° 45. ... Mean Result. Position 2° 49' np {15 Obs.) ; Epoch 1824.99 ; Distance io".939 (10 Obs.); Epoch 1824.94. and positions 0/4,58 double and triple stars y C^c. 7t No. CCCCLXXV. R. A. 5^ iQ"* ; Decl. 8** 13' S. 82 (Bode) Orionis ; Struve, 171 ; IV. 87. Double ; 8th and 10th magnitudes. Passy ; January 17, 1825 ; Seven-feet Equatorial. DifF. = 0° 33' ; DifF. =o".649 Position = 86° 32' nf Distance := 35".436 5 Obs. 5 Obs. Diff. = 0° 33' I y^^ difficult. Passy : January 19, 1825 ; Seven-feet Equatoiial. 8th and 10th magnitudes. Position = 86° 41 nf\ c Obs. 1 DifF. = i« 3' ) ,, ,.^ ,^ Distance = 36".J53 "^ | 5 Obs. | DifF. = o".84i } ^^^7 difficult, Passy; February 9, 1825 ; Seven- feet Equatorial. 8th and 10th magnitudes. Distance = 34".645 ; 5 Obs. | DifF. = i".274. Very difficult. Mean Result. Position 86° 46' nf (10 Obs.) ; Epoch 1825.05 ; Distance 35".678 (15 Obs.) ; Epoch 1825.06. By a mean of two measures in 1783, the position comes out for that epoch 85° 24', differing but 1° 32' from the pre- sent. The distance at the beginning of 1783 was 29'*. 30, and the measure is called very exact; yet an increase of distance to the extent of 6". 38 is beyond probability, a cir- cumstance which proves the occasional occurrence of the micrometrical error already pointed out, even in distances so low as 30". (H.) 72 Mr. South' s observations of the apparent distances No. CCCCLXXVI. R. A. 5^ i2"> ; Decl. 18° 43' S. Struve, 170; Hist. Gael. 562. Double ; equal, each 7^ magnitude. Passy ; December 5, 1824 ; Seven-feet Equatorial. Position = 72° 39' n/or sp \ 5 Obs. DifF. = 1° 31') Distance = 39".74o | 5 Obs. DifF. = i".563 5 Passy ; December 10, 1824 ; Seven-feet Equatorial. Equal ; each 7i magnitude. Position = 72° 43' nfovsp\s Obs. I DifF. = 1° 8' ) ^ , Distance = 39 ".687 | 5 Obs. | Diff. = 0^577 5 ^^^^^7' Night favourable, observed on the meridian. Mean Result. Position 72° 41' nfoT sp ; Distance 39".7i3 ; Epoch 1824.94. No. CCCCLXXVII. R. A. 5^ i3™ ; Decl. 34° 43' N, Struve, 173 ; IV. 101. Double ; 9th and 12th magnitudes. Passy; December 23, 1824 ; Seven-feet Equatorial. Position = J7° \^' np \ 5 Obs. j Diff. = 2° 3'. Extremely difficult. Observations of distance cannot be obtained ; the night is become very cloudy. Passy ; January 25, 1825 ; Seven-feet Equatorial. 7th and 9th magnitudes. Position = 75° 33' np I 5 Obs. I DifF. = i** 7' "> Distance= 32".075 j 5 Obs. | DifF. =:o".553 3 Passy ; February 2, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 75° 55' np Distance = 31 ".85 3 5 Obs. 5 Obs. DifF. = o» 30' ) Diff. = o".962 Mean Result. Position 76° 14' np ( 15 Obs.) ; Epoch 1825.04 ; Distance 31^964 (10 Obs.) ; Epoch 1825.07. This measure of position, compared with that of 1783, presents only 14' of difference. The distances are however evidently not comparable, owing to the micrometrical irregu- larity already pointed out. (H.) and positions of 458 double and triple stars ^ ^c, 73 No. CCCCLXXVIII. R. A. 5^ 14™ ; Decl. 17° 13' N. Ill Tauri ; Struve, 174; V. 110. Double ; 7th and 10th magnitudes ; small, blue. Passy; January 17, 1825 ; Seven-feet Equatorial. Position = 1° 25' np Distance= i' i".823 5 Obs. I DiflF. = 0° 34' I n;fflr»if SObs.|Diff. = i".4i8 5^'®'"^*- Passy ; February 2, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position = 1° 10' np I 5 Obs. I Diff. = o° 52' ) ^.^ j^^ Distance= 1' i".703 5 Obs. | Diff. = o".48i5 ^ When the position wire was set purposely to zero, the small star remained below thfe wire, whilst the larger continued bisected by it, during their passage across the field. Mean Result. Position 1" lYnp; Distance i' i".763; Epoch 1825.06. There is no reason to suppose a change of position in this star, the angle of 1783 being 3° 48' w^. (H.) No. CCCCLXXIX. R. A. 5^ i6» ; Decl. 1° 39' N. Nova ; Double; 9th and 10th magnitudes. Passy ; March 5, 1825 ; Seven-feet Equatorial. Position = S2° iS' sp\6 Obs. | DifF. = i° 58' Extremely difficult. The night is become so bad, that observations of distance cannot be procured ; it is probably between 40 and 50 seconds. Passy ; March 5, 1825 ; Portable Transit. Observed R. A. of the larger star = 5''.i5'.34".23. Passy ; March 17, 1825 ; Seven-feet Equatorial. lOth and 11 th magnitudes. Position = coP '^4! sp C Obs. I DifF. = 0° 52' ) ,, . _ , ..«. . Distance= 46".427 ^ 5 Obs. | DifF. = i".oipl ^^^^^"^^^y^^^^"^^- MDCCCXXVI. / 74 Mr. South's observations of the apparent distances No. CCCCLXXIX. continued. Passy ; March 26, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 51° i' «;> I 5 Obs Pistance=46".833 5 Obs ^^^•Z°: 3^1 Very difficult. DifF, Observed by twilight, without artificial illumination. A distant star C of the 5th magnitude follows A to the North. Measures of A C. Passy ; March 17, 1825 ; Seven-feet Equatorial. Position = 54* 44' nf I 5 Obs. DifF. = 0° 29' ) „ ^ ... , Distance = 2' i^".6go \ 5 Obs. DifF. = d'M^ \ ^^ twilight. Without artificial illumination. Passy; March 26, 1825 ; Seven-feet Equatorial. 9th and 5th magnitudes. Position = 54° 46' nf I 3 Obs. I DifF. = 0° 32O ^ ^ ... , ^ Distance= 2' 37".6i5 | 3 Obs. | DifF. = o".4s65 ^^ twilight. Without artificial illumination. Mean Result. of AB. Position 51° 21' sp (16 Obs.); Epoch 1825.20; Distance 46".630 (10 Obs.) ; Epoch 1825.22. of AC Position 54*45' w/(8 Obs.); Distance 2' 38". 162 (8 Obs.); Epoch 1825.22, The star C being to the north of A. No. CCCCLXXX. R. A. 5»» 16- ; Decl. 1° 45' N. Struve, 177 ; I. 52. Double; 9th and 12th magnitudes ; small, blue. Passy ; January 6, 1825 ; Seven-feet Equatorial. Position = 54** Ki' tip 7 Obs. I DifF. =. 6° o' ) t- • 1 j-/p , Distance = 2*974 5 Obs. | DifF. = 0^432 ] Excessively difficult. Observed when 15 minutes west of the meridian. Stars very steady. The de- position of moisture on the inner and outer surfaces of the object-glass is becoming troublesome. Thermometer in the observatory stands at 24^ degrees. and positions 0/4,58 double and triple stars ^ &c, 75. No. CCCCLXXX. continued. Passy ; February 4, 1825 ; Seven-feet Equatorial. 9th and 12th magnitudes. Position = 49° 42' np I 7 Obs. DifF. = 5° 5' 7 Rxcessivelv difficult Distance = 2".99i ) 5 Obs. DifF. = o".4o8 5 Excessively dimcult. Whilst making these observations, I did not feel the slightest confidence in their accuracy ; the smaller star could only be seen by glimpses, and then very indis- tinctly; indeed this double star, as well as the 53rd of the 1st class (see the fol- lowing page), would be proper objects for Mr. Herschel's 20-feet reflector. Passy ; February 23, 1825 ; Seven-feet Equatorial. 9th and 12th magnitudes. Position = 47° 23' np | 6 Obs. | Diff. = 7° 11'. Excessively difficult. The night is tolerably good, but no measures of distance can be obtained. The stars, at the time of observation, were 50 minutes west of the meridian. The discordance between the first and two subsequent series of observations of position, is very considerable j it would seem to indicate an error in the measures obtained on the 6th of January j against them there is however nothing in the shape of memorandum, to be found in the rough journal ; on the contrary, the night of January the 6th was one of uncommon fineness. I have tried to re-observe this star several mornings during the present and the last months, but without success ; indeed, except the weather is unusually favourable, the star, with my instruments, can scarcely be recognized as double. Passy, October 22, 1825. Mean Result. Position 50° 48' np (20 Obs.) ; Epoch 1S25.08 ; Distance 2".982 (10 Obs.) ; Epoch 1825.05. The mean of four angles in 1782 and 1783 gives 51° 47' np for the position of this star (Sir W. H. MSS.) A measure in 1802 makes it 50° 1' np " very exact." This star then is liable to no change of position. (H.) 76 Mr, South' s observations of the apparent distances No. CCCCLXXXI. R. A. 5^ i7" ; Decl. 2** 46' N. Struve, 180; I. 53. Double; 8th and 12th magnitudes; small star decidedly blue, and bears but a very feeble illumination. A star of the 8th magnitude precedes it to the north. Passy : January 6, 1825 ; Seven-feet Equatorial. Position = 45° 28' nf 7 Obs. I DifF. = 6° i' ) Excessively difficult Distance = f.099 5 Obs. J Diff. = 0^505 § Excessively ditticult. Observed on the meridian. Night unusually fine. A double star of the 6th class follows this to the north, but is too faint for measures of accuracy. Passy ; February 11, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position = 37° 10' nf 7 Obs. DifF. = 2°c6M „ . , ..^ ,, Distance =3".304 ^ 5 Obs. DifF. = o".336p^^«"^^^y ^^^c^^*' Stars extremely unsteady. On the meridian when observed. Passy ; February 23, 1825 ; Seven-feet Equatorial. 9th and 12th magnitudes. Position = 3f 49'-/ 7 Obs. Diff. = 6^ , 7' U^,,,,i,,i difficult. Distance = 3 .777 5 Obs. Diff. = o .408 > ' Observed when 35 minutes west of the meridian. The small star is decidedly light blue. The observations of position of this double star are by no means satisfactory. The two last sets agree sufficiently well, but differ to an enormous extent with the first series ; yet the night of the 6th of January was remarkably favourable for de- licate observations, and there is nothing prejudicial to their accuracy entered in the rough Journal. I have tried to re-observe this double star during the present au- tumn, but unfavourable weather has prevented me even from seeing it, as a double star. Passy; October 22, 1825. Mean Result, Position 40° 29' nf(Qi Obs.); Distance 3^393 (i5 Obs.) ; Epoch 1825.09. In 1783 the position v^as 43° 24' nf, and a measure in 1 802 gave 44° 6' nf for the angle, so that no change of conse- quence can have taken place in this star. ( H. ) and positions of 458 double and triple stars, &c. 77 No. CCCCLXXXII. R. A. 5^ 17" ; Decl. 11° 28' S. Struve, 179 ; Hist. Gael. 563- Double; 10th and 10^ magnitudes ; pale; ill defined stars, bearing scarcely any illumination. Passy ; January 17, 1825 ; Seven-feet Equatorial. Position = 75° 36' sp\ c Obs. I DifF. = i° n' ) r- ^ , j-n: ^. Distance = i2".978 ^ | 5 Obs. | Diff. = o".sos ] Extremely difficult. Passy ; January 19, 1825 ; Seven-feet Equatorial. lOth aud 10^ magnitudes. Position = 76° 12' sp c Obs. I Diff.= 1° 52') ^j ^ , .-n; u Distance = ii".38s 5 Obs. | Diff.= i".o82l Extremely difficult. Passy ; February 9, 1825 ; Seven-feet Equatorial. • lOth and 10 J magnitudes. Distance = ii".399 I 5 Obs. | Diff. = i".346. Extremely difficult. The night is remarkably fine. Mean Result. Position 75** 54' sp ; Epoch 1825.05 ; Distance ii".392 ; Epoch 1825.09. (Rejecting the observations of Distance made January 17th.) No. CCCCLXXXIII. R. A. 5^ 17" ; Decl. S3° 38' N. Nova ; Double ; 7th and 9th magnitudes ; several stars in the field. Passy ; February 12, 1825 ; Seven-feet Equatorial. Position = 30° 58' nf 5 Obs. ! Diff. =: i* i' ) ^..^ , Distance = i' 27^77 1 5 Obs. | Diff. = i".0345 ^^"^^ult. The small star bears a very insufficient illumination. Passy; February 17, 1825 ; Seven-feet Equatorial. 8th and 9f magnitudes. Position = 30° 49' nf 5 Obs. I Diff. = o® 40' ) j^-a- u Distance = i' 27".434 5 Obs. | Diff. = i".s6s > -^^"^cult. The small star is faint. Mean Result. Position so** 53' «/; Distance i' 2 7*. 602; Epoch 1825.11. 78 Mr. South' s observations of the apparent distances No. CCCCLXXXIV. R. A. 5^ 18™ ; Decl. ss'' ai' N. Nova ; Double ; 8th and 8^ magnitudes. Passy; February 12, 1825; Seven-feet Equatorial. Position = 8o<» 15' */ | 5 Obs. I Diff. = 1° 35' ) Distance = 59".5 34 j 5 Obs. | DiiF. = o".793 j A star of the nth magnitude is */ about 38° ±, and distant nearly 2| times as far^ from the larger of these two stars, as they are from each other. No measures of it can be procured. Night very fine. Passy; February 17, 1825 ; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 79« 47' sf 5 Obs. I DifF. = 1° 2' | Distance = 5 8".5 62 5 Obs. | DiiF. = o".962 j Passy; February 18, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Distance = ^%".6^6 \ 3 Obs. | Diff. = o".288. Very difficult. The night is become cloudy; no more observations dan be procured. Mean Result, Position 80° 1'^/; Epoch 1825.12 ; Distance 58".955(i30bs.); Epoch 1825.12. No. CCCCLXXX V. R. A. 5'' 19"" ; Decl. 29° 24' N. ' Struve, 183; IV. 110. Double; 7th and 10th magnitudes. Passy ; February 23, 1825 ; Seven-feet Equatorial. S Obs. I Diff. = 1° lo' ) __ ^_ . 5 Obs. I Diff. = o".72i \ V^O^ difficult. Position =82° 10^ np Distance = i5".26i Passy; March 5, 1825 ; Seven-feet^ Equatorial. 7th and 10th magnitudes. ■ "' Position = 81° 34' np \ 5 Obs. I Diff. = 1O27' > ^ Distance = is".63i | 5 Obs. | Diff. = o".48i > Extremely difficult. The small star scarcely bears the most feeble illumination. Night not very favourable. and positions of^fSS double and triple stars, ^c, 79 No. CCCCLXXXV. continued. Mean Result. Position 81° 52' np ; Distance 15".446 ; Epoch 1825.17. A measure of the position of this star in 1783 gave 74° 54' np, which differs 6° 58' from the present angle, being a change of + o°.i7o per annum, a very considerable quantity for so distant a star. However, the great difficulty of the measures must make us cautious in ascribing this to a real motion. The distance presents no sensible alteration. (H.) No. CCCCLXXXVI. R. A. 5^ 26" ; Decl. 5° 32' S. 6 Orionis ; Struve, 194 ; HI. 1, Quintuple ; A of the 6th, B the 7th, C 75:, D of the 8th, and E of the 12th magnitudes. The four first stars form the Trapezium, in the nebula of Orion. Measures of A B. Blackman-street ; December 27, 1823 ; Five-feet Equatorial. Position = 40* 16' » j9 j 8 Obs. DifF. = 4° 39' ) „ Distance = 13".293 | 8 Obs. [ Diff. = ©".979 j ^^"^V- Blackman-street ; December 29, 1823 : Seven-feet Equatorial. , , , lih and 8th magnitudes. Position = 40° c' np I 8 Obs. Diff. = 2° 2c' ) tt • r Distance = iVisi | 3 Obs. Diff. = o''.i92 J Unsatisfactory. No more observations of distance can be obtained : the night is become cloudy; indeed whilst those here given were procured, the stars were only visible by glimpses, and then were very indistinct. Blackman-street ; December 30, 1823 ; Seven-feet Equatorial. 6th and Jth magnitudes. Position = 41" 3' np 6 Obs. J Diff. = 2° 2' ) ^ , , , Distance = i3".85i 6 Obs. | Diff. = i".0345 ^^^^^^^^^ steady. ^ 80 Mr, South' s observations of the apparent distances No. CCCCLXXXVI. continued, Passy ; March 17, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. DifF. = 1° 8' 7 c^ . DifF. = o".529r^'^^y- Position zz 41° 29' np I 5 Obs. Distance =r 13". 140 j 5 Obs. Observed when i\ hour west of the meridian; but the night very favourable. Passy ; March 18, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position = 41° 53' np 5 Obs. DifF. =: o" 54' 1 t , , , . Distance - i2".849 5 Obs. DifF. = o".74S ] ^o^erauiy steady. Measures of A C. Blackman-street ; January 26, 1824 ; Five-feet Equatorial. 6th and 7? magnitudes. Position =s 29* iz' nf\ 5 Obs. Distance = i3".558 j 5 Obs. DifF. = 2° 13' ) ,T- u. u DifF. = o".474l Night hazy. Blackman-street; January 27, 1824 ; Seven-feet Equatorial. 7th and 8| magnitudes. Position = 300 39' nf Distance = 14". 2 24 5 Obs. I DifF. = 1° 12'. Night unfavourable. 5 Obs. j DifF. = o".i92. Stars very faint. Passy; March 17, 1825 ; Seven-feet Equatorial, 6th and 7i magnitudes. Position = 29* 35' nf\ 5 Obs, I DifF. == 1° 31' \ ^. , Distance = i3".ao2 \ 5 Obs. | DifF. = i".226 j ^^^^^V- Observed when if west of the meridian; but the night very favourable. Passy ; March 18, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position = 30° 1 8' nf Distances 13". 3 46 DifF. = 2° 15' > T, ^ .,. ,, DifF. = o".529j^yt^^^^ght. 5 Obs. 5 Obs. Observed without artificial illumination. Measures of A D. Blackman-street ; January 26, 1824 ; Five-feet Equatorial. 6th and 8| magnitudes. Position = 760 9' w» 1 c Obs. I DifF. = 1° 25' ) xt-^i,* r li Pistance = 1 7".43o ^ | 5 Obs. j DifF. = o".947 j ^^^ht unfavourable. and positions of 4fSS double and triple stars, &c. 81 No. CCCCLXXXVI. continued. Blackman-street ; January 27, 1824 ; Seven-feet Equatorial, 6th and 8| magnitudes. Position 1= 72° 49' np Distance = i6''.465 5 Obs. I DifF. = 1° 43' ) 5 Obs. I DiiF. = o".986j Same date ; Five-feet Equatorial. Position = 75° 33' np { 6 Obs. j DifF. = 2° 8'. Observed when two hours west of the meridian. Passy ; March 17, 1825 ; Seven-feet Equatorial. 6th and 8th magnitudes. Position =74^* 52' w;' 5 0bs. lDiff. = i°39')y . Distance = 16". 132 5 Obs. j Diff. = i".io65 ^^^ ^^^^^J"' Observed when two hours west of the meridian, but under favourable circumstances. Passy ; March 18, 1825 ; Seven-feet Equatorial. 6th and 8th magnitudes. Position =7S; 45' «? 5 Obs. Diff. = 0° 42' | Tolerably steady. Distance = i6".7 1 3 5 Obs. Diff. = i".oio5 ' ' Measures of A E. Blackman-street ; December 30, 1823 ; Seven-feet Equatorial. 6th and 12th magnitudes. Position = 57° 30' nf± ; single observation. Measures of distance cannot be obtained, for the small star under the slightest illumination becomes invisible. Blackman-street; January 26, 1824 ; Five-feet Equatorial. 6th and 12th magnitudes. Position = 58° 35 «/± ; single measure. No observation of distance can be procured. MDCCCXXVI. m 8i Mr, South's observations of the apparent distances No. CCCCLXXXVI. continued. Blackman-street ; January 27, 1824 ; Five-feet Equatorial. 6tli and I2th magnitudes. Position =59° 20' nf-±. ; single observation. The small star will not bear the slightest illumination ; measures of distance • impracticable. Passy ; March 18, 1825 j Seven-feet Equatorial. 6\ and 12th magnitudes. Distance:: 1' 59".309±: | 5 Obs. | Diff. = i".370. Excessively difficult. The star E is also double of the 5th class ; but its smaller star, which is south preceding, is so extremely faint, that although the night is unusually fine, I cannot obtain even approximate measures of it. Passy ; March 24, 1825 ; Seven-feet Equatorial. 6th and 12th magnitudes. Distance = i\^6".g20 ± | 5 Obs. [ DifF. = o".793. Excessively difficult. Observations liable to some inaccuracy. Mean Result. of A B. Position 40° 48' np(s^ Obs.) ; Distance 13".453 (25 Obs.) ; Epoch 1824.48. of AC. Position 29° 56' nf (20 Obs.) ; Distance 13".582 (20 Obs.); Epoch 1824.64. of AD. Position 75° 3' np (26 Obs.); Distance 16".685 (20 Obs.); Epoch 1824.64. of AE. Position 58° 28' nf±{s Obs.) ; Epoch 1824.05 ; Distance 1' 58".ii4±(io Obs.) ; Epoch 1825.21. In taking the mean, each observation has been allowed equally good. and positions 0/4^58 double and triple stars, &c, 85 No. CCCCLXXXVII. R, A. 5^ 26"^ ; Decl. 21° 5S' N. Struve, 192 ; I. 70. Double ; 9th and 9-^ magnitudes. Passy ; December 29, 1824 ; Seven-feet Equatorial. Position = 21^ 24' sp 5 Obs. I DifF. =zz° 11' \ p..^. ,. Distance = 3".i28 5 Obs. | DifF. = o".6oi j ^^^^cuit. Passy ; January 2, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 21; o'sp\6 Obs. Diff. = 60 56' 1 Extremely difficult. Distances 2 .450 j 5 Obs. Ditf. = o .432 3 ?assy ; February 2, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 220 32' sp I 6 Obs. I DifF. = 3° 32' ) Unsteady ^- Distance = 3".332 | 5 Obs. | DifF. = o".240 5 ^"steaay. Measures extremely difficult. Night unfavourable. Mean Result. Position 21° 39' sp (17 Obs.) ; Distance 2^.970 (15 Obs.) ; Epoch 1825.03. The position at the Epoch 1782.86 was 36° 24' sp. A change therefore of +14° 45' has taken place in the angle of this star, being + o°.35o per annum, direct, or in the direction sp nf. This is too large a quantity to be attri- buted to error of observation, and the star therefore in all probability belongs to the class of binary systems, and should be carefully watched. (H.) §4 Mr. South' s observations of the apparent distances No. CCCCLXXXVIII. R. A. 5^ 26- ; Decl. 5° 34' S. Seq. i"**- 6 Orionis ; Nova ; Double ; 6th and 7th magnitudes. Blackman-street ; January 26, 1824; Five-feet Equatorial. Position = 2° 3' */ 1 5 Obs. I DifF. = o° 46' ) ,... , , ^ , , Distance = s^"'^4 \ 5 Obs. \ Diff. = i'ljA,] ^'^^^ ^^^^ unfavourable. The first of these stars follows A of 6 Orionis about seven seconds of time, and is about 1' 32" to the south of it. Blackman-street ; January 27, 1824 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position = 1° o' «/ 1 5 Obs. DifF. = o" 3S' ) Distance= 5i".364 I 5 Obs. DifF. = o".962 > - Passy ; March 24, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. Distance = 52".409 | 5 Obs. | DifF. = o".529. Very steady. Observed by twilight, without artificial illumination. Mean Result. (The observations of distance taken January 27, 1824, being rejected) Position 1° 46' sf\ Epoch 1824.07 ; Distance 52".4i8 ; Epoch 1824.64. Observations to connect this double star with 6 Orionis. Measures of A of 6, and of A of the following double star. Passy ; March 19, 1825 ; Seven-feet Equatorial. Diff! = o''.6oi } ^^'■y satisfactory. Position = 43° 32' «/ I 5 Obs. Distance = 2' i4".90o | 5 Obs. Observed by daylight, the sun shining. Passy ; March 24, 1825 ; Seven-feet Equatorial. Position = 43° 41' ./ 5 Obs. I DifF. = 0° 18' ) „ . Distance = 2' i4".833 5 Obs. | Diff. = o".48i ] ^^^ "^^^^^ Observed by daylight ; observations good. Mean Result. Position 43** s6' sf Distance 2' 14^.866 ; Epoch 1825.22. (The star A of the following double star being to the south of A of fl Orionis.) and positions of 4:6^ double and triple stars, &c. 85 No. CCCCLXXXIX. R. A. 5^ 26" ; Decl. &> i S. Prsec. < Orionis ; Nova ; Double ; 7th and 7-J magnitudes. If < Orionis be brought into the centre of the field, this double star will be found in the apparent upper part of it ; a line drawn through the centres of its two stars will pass to the north of ; Orionis ; its larger star precedes ; 23 seconds of time, and is about 5^ minutes to the south of it. Black man-street; January 30, 1824 ; Five-feet Equatorial. Position = 49° 21' jp I 5 Obs. | Diff. = i*> 5'. Difficult. The night is very bad; stars too faint for accurate measures of distance j the small star of » Orionis is invisible. Blackman-street ; February 1, 1824 ; Seven-feet Equatorial. 6th and Jth magnitudes. Position = 49° V sf\s Obs. DifF. = 0° 53' ) Unsatisfactory Distance = lf.M% j 5 Obs. DiiF. z= i".oio5 ^nsatisractory. Stars very unsteady ; night by no means good. Blackman-street ; February 9, 1824 ; Five-feet Equatorial. 6th and 7th magnitudes. Distance = 36". 338 J 5 Obs. | DifF. =: o".947. Very unsteady. Passy ; March 26, 1825 ; Seven-feet Equatorial. 7 th and 8th magnitudes. Distance = n".^^\ \ 5 Obs. | DifF. = o''.745. Tolerably steady. Observed by twilight, without artificial illumination. Mean Result. Position 49° 11' 5^ ; Epoch 1824.08 ; Distance 37^116 (15 Obs.) ; Epoch 1824.47. 86 Mr. South' s observations of the apparent distances No. CCCCXC. R. A. 5^ 27" i Decl. 5° 34' S. Seq. Q""^"- 0 Orionis ; Nova ; Double ; 9th and 12th magnitudes. The larger of these stars , follows the bright star A of 5 Orionis, about 15 seconds of time, and is about 1' 49" to the south of it. Passy ; February 17, 1825 ; Seven-feet Equatorial. Position =: 56° 3'*p Distance rr i' \j".6o() 7 Obs. I DifF. = 1° 40' 7 ^ , ,.^ , 5 Obs. I DifF. = o".889 j Extremely difficult. Night clear, but the stars are unsteady. Passy ; February 23, 1825 ; Seven-feet Equatorial. ; 8th and 11th magnitudes. Position = 55° 45' «j9 Distances: 1' 17". 751 5 Obs. \ DifF. = o« 56' ) ^r A-a 1^ 5 Obs. I DifF. = i".o82P^'^y d^«^^"l*- Mean Result. Position 55° 5Q' sp (12 Obs.); Distance 1' i7".68o ; Epoch 1825.21. No. CCCCXCI. R. A. 5*^ 27 ; Decl. 6° 2' S. « Orionis ; Struve, 195 ; III. 12. Triple ; large, w^hite ; the small stars, particularly the nearest, decidedly blue. A of the 4th, B of the 11th or 12th, and C of the 15th magnitudes. Measures of A B. Blaekman-street ; February 1, 1824 ; Seven-feet Equatorial. Position = 52° 13' «/ I 14 Obs. DifF. = 7° 30' ) ^ ^ , ,.«. ,, Distance=i3".5i8 I 6 Obs. DifF. = ;".2o2 J ^^^''""'^^y ^^^^"^^- Night is clear, but the stars are very unsteady. and positions of ^B^ double and triple stars, ^c, 87 No. CCCCXCI. continued. Same date ; Five- feet Equatorial. Position = 52° n' */| 8 Obs. I Diff. = 3° 37'. Very difficult. Distances: 10". 867 j 3 Obs. | Diff. = I'.zg^, Extremely difficult. The night having become hazy, the stars are now remarkably steady. During the observations of position, the haze took off the flare of the large star, and left the small one sufficiently distinct under a good illumination ; after however the position series was procured, a dense fog supervened, the small star became very indistinct, and shortly was invisible ; on this account, no more measures of distance could be obtained, and those gotten are deserving of little confidence. Blackman-street ; February 9, 1824 ; Five-feet Equatorial. 4th and 12th magnitudes. Distance = 1 1".843 | 6 Obs. ] Diff. = o".727. Passy ; March 5, 1825 ; Seven-feet Equatorial. 4th and 12th magnitudes. Position = 50° 49' sf 5 Obs. I Diff. = 1° 33' ) y „nsatisfactorv Distance = I2".3i8 5 Obs. | Diff. = i".o58 j ^^^ unsatisfactory. Stars excessively tremulous. Passy ; March 19, 1825 ; Seven-feet Equatorial. 4th and 1 1th magnitudes. Position = 52° 7' sf Distance = 11 ".154 5 Obs. 5 Obs. Diff. = 2° 15' I Tj ^ .1- ,^ Diff. = o".62sl^y*^^^^S^^- The sun in the horizon when these observations w^re commenced. The light blue colour of the small star is very distinct. No artificial illumination employed. Measures of A C. Blackman-street ; February 1, 1824 ; Seven-feet Equatorial. 4th and 15th magnitudes. s:it" 1 ;^;;t;i* 1 1 8^:: | si: 1 1;:^, } ^--'-^ ""«-'«• Measures, particularly of distance, liable to some inaccuracy. Mean Result. of A B. Position 51*' 58' sf {3^ Obs.) ; Epoch 1824.82 ; Distance i2".o85 (25 Obs) ; Epoch 1824.64. of AC. Position 13° 26' sf± (5 Obs.); Distance 4t^".784 (5 Obs.); Epoch 1824.08. 88 Mr. South' s observations of the apparent distances No. CCCCXCI. continued. The positions of B and C respectively in 1781, were 43° 51' sfj and 11'' 19' sf, the former indicating a change of 8® 7', and the latter of only 2'' 7'. The distances have un- dergone little change. Here the fixity of the more distant star may be regarded as affording presumptive evidence of a motion in the nearer one, and that to a considerable amount (-f o°.202 per annum, or direct.) This star therefore merits attention. (H.) No. CCCCXCII. R. A. 5^ 27" ; Decl. so'' 22' N. 26 Aurigse ; Struve, 196 ; III. 64 ; Double ; 6th and 10th magnitudes ; small, blue. Passy ; December 29, 1824 : Seven-feet Equatorial. Position = i°45' sp I 6 Obs. I DifF. = i° 28' 7 ^._ , Distance = 12". 265 \ 5 Obs. | DifF. in o".4s6 ] ^i^cult. After these measures were secured, the position wire was purposely set to zero. The small star is decidedly above the wire, whilst the larger one remains bisected by it, during their progress across the field. Night very favourable ; it freezes slightly. Passy ; January 25, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position = 1° 32' sp 6 Obs. DifF. = 0° 53' \ y difficult Distance = I2".388 5 Obs. DifF. = o".9i3 ] ^^^^ mmcult. Mean Result. Position 1° 38' sp (12 Obs.) ; Distance 12".327 (10 Obs.); Epoch 1825,03. In 1783 the position is stated (MSS.)to have been q^ s6' np, and the distance i3".4i. In 1802 the angle v^as measured at 3° s^' np, but (for reasons assigned), this w^as regarded at the time as a manifestly false measure, and the small star was judged to be exactly preceding. The total change of angle is 4° 14', a considerable quantity for mere error of observation in a star of the 3d class, and which (when the observation of 1802 is considered ), may lead to a suspicion of a very slow relative motion. (H.) and positions q/*458 double and triple stars, C^c. 89 No. CCCCXCIII. R. A. 5^^ 3o™ ; Decl. 0° 15' S. Nova ; Two double stars in the field. The preceding is of the 6th class ; the following of the 2nd or 3rd. The preceding. Passy ; December 29, 1824 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 70 59' sp I 5 Obs. f DifF. = 0° 48') ^.^ . Distance = 2' i7".gS2 \ 5 Obs. | Diff. = ©".9865 ^»*cult. Passy ; January 16, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position =z S° 17' sp \ 3 Obs. J DifF. = 0° 40'. Very difficult. Night is become cloudy. Passy; January 17, 1825 ; Seven-feet Equatorial. 8th and 1 0th magnitudes. Position = 8° ia.' sp I c Obs. DifF. = 0° 24' ) ,. ..^ , Distance = 2' i8".6s3 | 5 Obs. DifF. = i".io6§ ^^^ difficult. The small star is very faint, and bears only the most feeble illumination. Mean Result. Position 8° 9' sp (^13 Obs.); Epoch 1825.03 ; Distance 2' i8".3i7 ; (10 Obs.) ; Epoch 1825.02. No. CCCCXCIV. R. A. 5^ so" ; Decl. o'' 15' S. Nova ; sequens No. 493 ; Double ; 10 and loi magnitudes ; both pale blue, and bear scarcely any illumination. Passy ; December 29, 1824 ; Seven -feet Equatorial. Position = 28** 45' np c Obs. I DifF. = 2° 35' ) ^j ^ 1 j-a: 1* Distance = 1 i'.49i ^ 5 Obs. | DifF. = i".73^ j Extremely difficult. MDCCcxxvi. n ^\ Mr. South' s observations of the apparent distances .8 No. CCCCXCIV. continued. Passy ; January 25, 1825 ; Seven-feet Equatorial. lOth and lOf magnitudes. Position = a6; 58' np 5 Obs. I Diff. = 2° 27' > Extremely difficult. Distance = II .555 5 Obs. | Difr. r= o .986 ) ' Neither star bears a good illumination. Night fine. Mean Result. Position 27° 51' np ; Distance ii".52s ; Epoch 1825.03. No. CCCCXCV. R. A. 5*^ 30» ; Decl. 29° 23' N. Struve, 197 ; Hist. Gael. 260 ; Double ; 7 and 73- magnitudes. Blackman-street ; December 22, 1823 ; Five-feet Equatorial. Position r= 77° 7' nf Distance == 26".27o 5 Obs. 5 Obs. F. = I* o' ) F. = o".758 ] DifF. = I* o' DifF. Passy ; December 22, 1824 ; Seven-feet Equatorial. 7 and 71 magnitudes. , rr Position = 77° 1 7' nf Distance = 26".732 5 Obs. I Diff. = 0° 53' ) Z = o".i68 5 5 Obs. 1 Diff. Mean Result. Position 77° 12' nf'. Distance 26''.5oi ; Epoch 1824.48. No. CCCCXCVI. R. A. 5^ so™ ; Decl. 15° 15' N. Struve, 199 ; Hist. Gael. 262 ; Double ; 8th and loth magnitudes ; small, blue, and bears a very tolerable illumination. Passy ; December 10, 1824 ; Seven-feet Equatorial. Position = 4° 54' np Distance = ^".j^z 5 Obs. I Diff. = 1° 45' ) rs ^u -J- 5 Obs. I Diff. = o".4o8l ^" *^ meridian. and positions 0/4,58 double and triple stars ^ &c. 91 )330 No. CCCCXCVI. continued. Passy; January 25, 182-5 ; Seven-feet Equatorial. 8^ and 9f magnitudes. Position =: 4° 44' nj? 5 Obs. | DifF. = i° 18' 7 Distances 9".98 3 5 Obs. | Diff. = o".553 3 Mean Result. Position 4° 49' np ; Distance 9". 867 ; Epoch 1825.00. No. CCCCXCVII. R. A. 5^ S?"" ; Decl. 4° 20' S. 187 (Bode) Orionis ; Struve, 204 ; Double; 7th and 12th, or 15th magnitudes; the small star . . will not bear the least illumination. Passy ; January 6, 1825 ; Seven-feet Equatorial. Position = 2° 48' nf I s Obs. I DifF. = 3° 23' } ^ ^ meridian Distance = 8".o48 | 5 Obs. | DifF. = o".s29 5 ^" *^^ meridian. The night is remarkably fine, and the stats are extremely steady; still the mea- sures of this double star are so excessively difficult, that the observations of it, although made with every possible care, may be liable to error. To attempt to measure it, except under the most favourable circumstances, will always be useless. I had often looked attentively for this small star, both here and in England, fully persuaded from the authority of Mr. Struve* that it existed ; but till this evening, it does not appear from my Observatory Journal, that I have eren once suspected that I saw it. Passy ; February 6, 1825 ; Seven-feet Equatorial. 7th and loth magnitudes. Position = 3*> 26' nf\ 5 Obs. Diff. = 0° 34' X Excessively d^cult' Distance = 7^.287 | 5 Obs. Diff. = o".62S j Excessively diflicult. Night very favourable for delicate observations; still the extreme faintness of the small star renders the measures open to suspicion. Mean Results Position 3° y nf; Distance 7".667 ; Epoch 18^5.06. • Mr. Struve's ciatalogue tontaihs the {Places of severalJtftire called double by PiAzzi; in numerous instances however, I am satisfied that Piazzi's instrument has deceived him. 9i Mr. South' s observations of the apparent distances No. CCCCXCVIII. R. A. p,^ 37" ; Decl. 22° 31' S. y Leporis ; V. 50. Double ; 5th and 8th magnitudes. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position = y(f 42' «J9 I 5 Obs. DifF. = 0° 41' ) Distance= r 33".i82 I 6 0bs. I>\S. = i".\^^] Passy ; January 19, 1825 ; Seven- feet Equatorial. 6th and 8th magnitudes. Position = 79<* ^' np 15 Obs. Distance = i' 34".5S3 \ 5 Obs. DifF. = 0° 24' ) Diff.z: I ".370) Passy ; February 5, 1825 ; Seven-feet Equatorial. 5th and 8th magnitudes. Distance = i' 33".928 | 5 Obs. | DifF. = o".745 Mean Result. Position 79° 25' np (lo Obs.); Epoch 1825.03 ; Distance 1' 33".844 (16 Obs.); Epoch 1825.05. Sir W. Herschel has no measures of this star, and there is even a doubt of its identity with V. 50. (H.) No. CCCCXCIX. R. A. 5^ sS'" ; Decl. 6" 23' N. 52 Orionis ; Struve, 207 ; I. 20. Double ; equal ; each of the 8th magnitude. Blackman-street ; March 6, 1824 ; Five-feet Equatorial. Position = 68"> 25' sp or «/ 1 5 Obs. DifF. = 2° 49' | Distance = i".65 1 j 2 Obs. DifF. = o".474j Blackman-street ; March 12, 1824 ; Five-feet Equatorial. Equal ; each of the 8th magnitude. Position =70° 13' 50 or 7*/" c Obs. DifF. = «• 6' ) ,, Distance = i".655 5 Obs. DifF. =z o".569 \ ^^^ unsteady. These stars are separated with 133, but are best observed with 303 ; the night is very clear. and positions 0/4.68 double and triple stars, ^c, 93 No. CCCCXCIX. continued. Mean Result. Position 69° 19' sp or nf; Distance i".654 ; Epoch 1824.18. This star has not undergone the slightest change. In 1781 its position was 69° 4i' ^^ ; in 1802 it was 69^ 57* sp; and its distance appears in hke manner to remain perfectly unaltered. (H.) No. D. R. A. 5^ 38"" ; Decl. 32° 66^ N. ' Struve, 206; Hist. Gael. 209 ; Double; 9th and 10th magnitudes. , . Passy ; Jauuary 6, 1825 ; Seven-feet Equatorial. < {■ Position = 1° 19' nf[ 5 Obs. 1 Diff. =0048' ) j^.^^^^^^ Distance = 58".738 \ 5 Obs. ) DifF. = o '.817 ) Passy ; January 28, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position =0*" 58' n/ Distance = 59".856 ^nMn-ff^'^^/! Difficult. 5 Obs. 1 Dm. = o".529 5 Passy ; February 5, 1825 ; Seven-feet Equatorial. Position = 1° i' «/| 5 Obs. = 59".786 1 ■ S?£- = °:r'l Difficult. Diff. = o".577> rM** Distance =: 59".786 | 5 Obs. Mean Result. Position 1° 6' nf {15 Obs.) ; Distance 59". 46o ; (15 Obs.); Epoch 1825.06. ^4l Mr, SouTH*s observations of the apparent distances No. DI. R. A. 5*^40'; Decl. 8° 28' S. Nova.; Double; 7th and 11th magnitudes. j r.ojjir . {\{ .'.j-offi^ssy ; March 8, 1825 ; Seven-feet Equatorial. Position = 87° 34' «p 5 Obs. (DifF. = i°47') „ ^ , ,._ ,-,10^1 Distance = 2i".387± (single observation) J ^^^^^^^^^^ ^^^^^1**. .. The night is become very bad j no more measures can be gotten ; and the accuracy of these perhaps may be called in question. Passy; March 10, 1825 ; Seven-feet Equatorial. 7th and 12th magnitudes. Position =88° i8' sp Distance z= 21". 615 ± 5 Obs. 3 pbs. DifF. =o°46' ) „ •,..«:, DiiF. = I ".202 \ Excessively difficult. The small star will scarcely bear the slightest illumination. .^^huiit^gs.rli mot I^ffK liij : iiMjjoG Mean Result. Position 87° 54' sp (10 Obs.); Distance 2i".558 ± (4 Obs.) ; .;.;;l EpQch, 182^^.1 8. ^ . , No. Dir. R. A. 5^ 45" ; D^cl. is'' 50'' N. Struve, 210: Hist. C«l. 313. VJHn Uouble; 8tH and 9th magnitudes. ^ Passy; January 6, 1825; Seven -feet Equatorial. Position = 39° 14' sf\ 5 Obs. [ DifF. = o<» 39' 7 Distance ==45". 1 71 | 5 Obs. | DifF. = o".577 j Passy ; January 19, 1825 ; Seven-feet Equatorial. 7th and 8th magnitudes. to' Position =: 39° 7' sf Distance = 45". 878 5 Obs. 5 Obs. DifF. r= 2° 8' > DifF. = o".865 5 Mean Result, Position 39' 10' sf'. Distance 45".524 ; Epoch 1825.03. and positions 0/4,58 double dnd triple stars, Qc." ' 9^ Nova ; r rr •'lot f)f ('n'.Q Double ; 7th and 9th magnitudes ; a star C of the 8th* mag- nitude precedes it to the north. Measures of A B. Passy ; January 19, 1825 ; Seven-feet Equatorial. Position = 43° p' sf j Obs. f Diff. =±i^^'i '-'- ' Distance = 39".68o 5 Obs. j Diff. 2= 2".i'ii 5 Passy ; Februaiy 4, 1825 ; Seven-feet Equatorial. 7th and 9th magnitudes. Position = 44° 42' sfl 5 Obs. | Diff. = 1* 13* f Distance =:4o".2 1 2 | 5 Obs. | Diff. =:o".962 ] • The small star is certainly blue. Measures of A C. Passy; January 19, 1825; Seven-feet Equatorial' 7th and 8th magnitudes. Position = 67° 13' n;> 1 3 Obs. j Diff. = 0° 22'. . . ,'\ Passy ; February 4, 1825 ; Seven-feet Equatorial. 7 th and 9th magnitudes. Position = 67O 19' n;, I 5 Obs. I Diff. = o** 43' ) Distance = 3' 2i".7i2 | 5 Obs. | Diffl = I'.ijo j Passy; March 26, 1825; Seven-feet EqiatoriaL 7th and 8th magnitudes. Distance = 3'2i".8i7l5Pbs. jDiff.= i".o82 .\MednJihsult, of AB. Position 44^*9'^/; Distance 39^946 ; Epoch 1825.07; of AC. Position 67° 17' np (8 Obs.) : Epoch 1825.07; Distance 3' 21^764 ; Epoch 1825.16. 96 Mr. South's observations of the apparent distances NP: DIV. R. A. 5^ 51" ; Decl. 20° , ipf S^-^ Struve, 215 ; Hist. Csel. 319. Double ; equal; each of the 10th magnitude. Passy; January 6, 1825 ; Seven-feet Equatorial. '.jvJL Position n 12° 22' * JO or nf Distance = 5".253 5 Obs. 5 Obs. Diff! = o".962 I Excessively difficult. These are pale, ill defined stars, bearing neither illumination nor magnifying power : till now I have only seen it as a single star : finding the measures difficult with 179, 1 tried 105; but although the stars were then distinctly separated, the instant sufficient light was admitted to render the micrometer wires perceptible, both stars became invisible. The measures (perhaps little better than cautious estimations) were gotten with the ordinary power of 179. The night is particu- larly favourable. I have tried to re-measure this double star several times ; but although the wea- ther has occasionally been very fine, I have not succeeded in seeing it double. Passy ; April 30, 1825. No. DV. R. A. 5^ 58"^ ; Decl. 14° 2'N. Nova ; in the field with Nos. 506 and 507 ; Double ; 9th and 9^ magnitudes, Passy ; January 28, 1825 ; Seven-feet Equatorial. Position = 85° 19' nf\ c Obs. DifF. = f lo' ) „ ,.0- ,. Distance = 2;".23 1 | J Obs. DifF. = o".889 \ ^^'^ ^'^^"^^• Passy; February 4, 1825; Seven-feet Equatorial. 93 and 10th magnitudes. Position = 84® 9' n/ 1 5 Obs. Distance =: 25".092 | 5 Obs. DifF!=:i".793 } Very difficult. Passy ; March 29, 1825 ; Seven-feet Equatorial. 9th and 9^ magnitudes. Position = 82° 58' n/j c Obs. I DifF. = i® %g' 1 „ ,.- , Distance = z^'.66^ | 5 Obs. | DifF. = i".8o3 | ^^^^ ^^"""^^ Observed when 2f hours west of the meridian. ^ n'-i .'' Mean Result. Position 84'' 9' nf ( 15 Obs. ) ; Distance 24''.662 (15 Obs.) ; Epoch 1825.13. and positions of 4}SS double and triple stars, &c. 97 ^Tf-r No. DVI. R. A. 5^ 59" ; Decl. 14° o' N. Nova; Double ; 8th and 10th magnitudes. Passy ; January 28, 1825 ; Seven-feet Equatorial. Position r: 19° 53' sf I 5 Obs. 1 DifF. = 2° 53' ) j.g. , Distance =2".202 | 5 Obs. | DifF. = o'^jOg] ^"^c"^'^- Night remarkably fine ; but the moisture deposited on the object-glass is sadly troublesome : it is absolutely necessary to remove it every three or four minutes for the purpose of wiping it. Passy ; February 11, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 190 14'^/ 1 5 Obs. I DifF. = i° 46' ) difficult Distance = 2".928 | 5 Obs. | DifF. = o".336 5 ^™cmt. Passy ; March 10, 1825 ; Portable Transit. Observed R. A. of the larger star = ^^ 58' ^6".S6. Passy ; March 29, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Distance = 3". 120 1 5 Obs. | Diff. = o".456. Difficult. Observed when two hours west of the meridian. Mean Result. Position 19° 3s' 5/(10 Obs.); Epoch 1825.09; Distance 2^.750 (15 Obs.); Epoch 1825.12. No. DVIL R. A. 5^ 59" ; Decl. 14° o' N. Nova ; Double ; 9th and 9 J magnitudes. The larger of these stars follows the double star, No. 506, two or three seconds of time, and is about 14 seconds to the south of it. Passy; January 28, 1825 ; Seven-feet Equatorial. Position = 470 24' 5 j7 I 5 Obs. j DifF. = i° 59' 1 Distance = 39".3 3 1 j 5 Obs. | DifF. = o".9i3 5 MDCCCXXVI. 0 98' Mr. South's observations of the apparent distances No. DVII. continued, Passy; February 4, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position =47° 43'«J9 j 5 Obs. J DifF. = i° 22' ) Distance = 4o".o62 | 5 Obs. | DifF. = i".443 > • • • • Mean Result. Position 47° 3S' sp ; Distance 39".696 ; Epoch 1825.08. No. DVIII. R. A. 6^ o" ; Decl. 2° 32' N. Struve, 216 ; Double ; 7th and 8th magnitudes. Passy ; December 5, 1824 ; Seven-feet Equatorial. Position = 22° 21' sf\ 5 Obs. Distance = 28''.377 | 5 Obs. DifF. = 0° 40' ) DifF. = o".9i35 Passy; December 10, 1824; Seven-feet Equatorial. 7| and 8th magnitudes. Position =: 22° 57' ,s/ 1 5 Obs. I DifF. = 0° 53' ) Distance = 2^' -991 \ 5 Ohs. J Diff. = o".72i | • • • • Passy ; February 5, 1825 ; Seven-feet Equatorial. 7J and 8th magnitudes. Distance = 29". 187 | 5 Obs. | DifF. = o".577. Measures of a distant star of the 12th magnitude. Passy ; February 5, 1825 ; Seven-feet Equatorial. Position = 16° 28' sf 1 Single observation 7 ppQ-t. ,0 c qq Distance = 2' I ".060 J Single observation j " 5-9 Mean Result. Position 22° 39' sJ(io Obs.); Epoch 1824.94 ; Distance 29". 18 7 (15 Obs.); Epoch 1824.99- and positions of 4f5S double and triple stars , &c. 99 No. DIX. R. A. 6^ 4™ ; Decl. 14° sC' N. Nova; sp No. 510 ; Double; 7th and 7^ magnitudes. Passy ; January 17, 1825 ; Seven-feet Equatorial. Position = 71° 58' *;> I 5 Obs. I Diff. Distance = 2' 49".i46 | 5 Obs. | Diff. Position = 71° 58' sp I 5 Obs. I Diff. = 0° 37' 7 ;=i".io6| • • • • Passy ; February 2, 1825 ; Seven-feet Equatorial. 8th and 8f magnitudes. Position =71° 57' sp Distance = 2' 48 ".7 3 2 S Obs. I Diff. =o»2i' } 5 Obs. j Diff. = i".298 Mean Result. Position 71° 57' sp ; Distance 2' 48".9S9 ; Epoch 1825.06. No. DX. R. A. 6^ 4" ; Decl. 14° 32' N. Struve, 219 ; Hist. Casl. 313. Triple ; A of the 8J-, B 9th, and C of the 12th magnitudes. Measures of A B. Passy ; December 29, 1824 ; Seven-feet Equatorial. Position = 6° 20' 5p I 5 Obs. I Diff. = 1° 29' 1 Distance = 5^922 | 5 Obs. | Diff. =o^553 j" South preceding this star, in the field with it, is a double star of the 6th class ; and north following also a triple star of the 5th and 6th classes : they may be mea- sured when the weather is favourable. Passy; January 17, 1825 ; Seven-feet Equatorial. * 8th and 9th magnitudes. Position =: y° 6' sp Distance = 5".939 5 Obs. 5 Obs. Diff. = i°36') Diff. =o".4565 loo Mr, South* s observations of the apparent distances No. DX. continued. Measures of A C. Passy ; December 29, 1824 ; Seven-feet Equatorial. 8 J and 12th magnitudes. Position = 64° 44.' nf I 5 Obs. I DifF. = o° 25' 7 y difficult. Distance = i' ^f-siZ I 5 Obs. 1 DifF. = i".6ii } ^^^ aimcuu. Passy ; March 30, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position = 640 41' nf 3 Obs. 1 Diff. = o^ 31' \ Extremely difficult. Distance= i 48 .457 3 Obs. | Diff. =0 .5053 ^ Observed when 2 j hours west of the meridian. Mean Result. of A B. Position 6° 43' sp ; Distance 5".930 ; Epoch 1825.02 ; of A C. Position 64° 43' nf{S Obs.) ; Distance 1' 47".879 (8 Obs.); Epoch 1825.12. No. DXL R. A. 6^ 4™ ; Decl. 36° 12' N. Struve, 218; Hist. Csel. 315. Double ; 7|- and 8th magnitudes. Passy ; December 29, 1824 ; Seven-feet Equatorial. Position = 54° 55' sp i 5 Obs. I Diff. = i** 31' ) Distances 1 1".99 1 | 5 Obs. | Diff. = o".625 j Passy ; December 31, 1824 ; Seven-feet Equatorial. 8th and 8f magnitudes. Position = 53° 31' «P I 5 Obs. 1 Diff. = i** 15' | ,, „, 4.r»«,„i«„c • Distance = ?i".3i8 "^ | 5 Obs. 1 Diff. = d'.s^s] ^^"^ tremulous. Stars only visible by glimpses. Cloudy. Mean Result. Position 54° 13' sp; Distance ii".654 ; Epoch 1825.00. and positions 0/4,58 double and triple stars y &c, idl No. DXII. R. A. 6^ 7" ; Decl. 47** n' N. Struve, 220 ; Hist. Csel. 383. Double ; 9^ and 10th magnitudes. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position = 0° 39' «p I 5 Obs. I DifF. = i° lo' ) -n:*-,,!*. Distances 8".374 I 5 Obs. | Diff. = i".37oi ^^^^^*- Passy ; January 25, 1825 ; Seven-feet Equatorial. lOth and 10| magnitudes. Position =o° 2z' sp\ c Obs. 1 Diff. = o° 40' | ,r ^ A;a:^,-,u Distance = 8".io3 j 5 Obs. | Diff. = C.^Szl ^^^ '^^®^"^*- These stars are so extremely obscure, that the observations of distance may be liable to some error. Mean Result. Position 0° 32' sp ; Distance 8".2s8 ; Epoch 1825.03. No. DXIII. R. A. 6^ 11" ; Decl. 21° 14' N. Nova ; Double ; 8th and 9^ magnitudes ; small, blue. Passy; February 12, 1825 ; Seven-feet Equatorial. Position := 1 2° 47' s p Distance =: 5 9'. 3 22 5 Obs. 5 Obs. Diff. = o" s6' I difficult. Diff. =: o".937 The small star does not bear a good illumination. Passy ; February 17, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = i»«> 53' « o I s Obs. Diff. = i° 37' ) t^.^. ,, .Distance = 58".505 "^ | 5 Obs. Diff. = o".;8i j ^^^^"^^- Small star very faint. Mean Result. Position 12° 50' sp ; Distance 5^" -91 3 ; Epoch 1825.11. 102 Mr. South' s observations of the apparent distances No. DXIV. R. A. 6^1*° ; Decl. 58° 30' N. 5 Lyncis ; Struve, 221 ; VI. 102. Double ; 6th and 9th magnitudes ; small, blue. Passy ; January 5, 1825 ; Seven-feet Equatorial. Position = 2° ^' np I 5 Obs. Distance = i' ^6".6j^o J 5 Obs. DifF. =o®5i' ) DiflF. = o".74S ) Passy; February 4, 1825 ; Seven-feet Equatorial. 7th and 9th magnitudes. Position = 2° g' np j 5 Obs. I DifF. = 0° 27' 7 Distance = I' 34".3 83 | 5 Obs. | DifF. = i".37o j Passy ; February 6, 1825 ; Seven- feet Equatorial. 7th and 9th magnitudes. Distance =: 1' 35'.3i2 | 5 Obs. j DifF. =: o".';g^. Mean Result. Position 2° 7' np (10 Obs.) ; Epoch 1825.05 ; Distance 1' 35".445 (i5 Obs.) ; Epoch 1825.06. The position of 1783 was 2° o' np, so that this star ap- pears perfectly unchanged in this respect. As for the distance, nothing can be concluded for reasons already stated. (H.) No. DXV. R. A. 6^ 12"^ ; Decl. 26° 47' N. Nova ; Double; 9th and 9|- magnitudes; bear but a feeble illumination. Passy ; February 12, 1825 ; Seven-feet Equatorial. Position = 78° 36' np I 5 Obs. DifF. = 0° 19' ) DifF. = o".793i Difficult. Distance = i8".86o | 5 Obs. Passy; February 19, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 78° 4s'«i> I 5 Obs. I DifF.= 1° 45' I Verv difficult Distance = 19".! 39 | 5 Obs. | DifF.= o".72i > ^^^ diHicult. Mean Result. Position 78° 40' np ; Distance 18^.999 ; Epoch 1825.13, and positions of ^^8 double and triple stars y ^c. 103 No. DXVI. R. A. 6^ 12^ ; Decl. 34° 53' S. Nova; Double ; 8^ and 9^ magnitudes ; a star C of the 6th mag- nitude precedes A to the south. Measures of A B. Passy ; March 5, 1825 ; Seven-feet Equatorial. Position = 87° 2' nf Distance = i' 6'.404 Obs. I DifF. = 0° 57' ) T^-ffi u Obs. |DifF. = I".o82l^^®*^^^*• Passy; March 10, 1825 ; Seven- feet Equatorial. 9th and 10th magnitudes. Obs. I DifF. = 0° S3' 1 r <- 1 j-a: u Obs. I DifF. = o".72 1 i Extremely difficult. The small star bears but the most feeble illumination. Position = 87° 9' nf Distances: i' 6". 139 Measures of A C. 8^ and 6th magnitudes. Passy ; March 5, 1825 ; Seven-feet Equatorial. Distance =: 27° 57' sp. Single Observation. Passy ; March 10, 1825 ; Seven-feet Equatorial. Position = 27° 39' sp I 3 Obs. I DifF. = 0® 14' ) Distance = 5' o".o48 | 3 Obs. | DifF. = i".659 > * * Passy ; March 28, 1825 ; Seven-feet Equatorial. Distance = 4' 59".902 | 3 Obs. | Diff. = i".i78. By twilight. Observed without artificial illumination. Mean Result. Of A B. Position 87° 5' nf; Distance 1' 6".2yi ; Epoch 1825.18. Of A C. Position 27° 43' sp (4 Obs.) ; Epoch 1825.18 ; Distance 4' 69" -91 5 (^ Obs.) ; Epoch 1825.21. 104 Mr. South' s observations of the apparent distances No. DXVII. R. A. 6^ 14- ; Decl. i6° 32' S. Nova; Double; 10 and io|- magnitudes. Passy ; February 23, 1825 ; Seven-feet Equatorial. Position =: 77° 17' sp \ 5 Obs. Distance =: 2i".y/^S j 5 Obs. Diff. = 2°24'|^^^j.^^^j^^ Diff. = i".707 Neither star bears sufficient illumination ; I rather suspect the accuracy of the distance. Passy ; March 10, 1825 ; Seven-feet Equatorial. Equal; each of the 11th magnitude. Diff! = l°'.f62 } Extremely difficult. Position = 78° S* s p or nf\ 5 Obs Distance = 23". 91 2 j 5 Obs Mean Result, Position 77° 42' sp or nf; Distance 23".830 ; Epoch 1825.16. No. DXVIII. R. A. 6^ 16"^ ; Decl. 16° 8' S. Struve, 223 ; Hist. Gael. 323 ; Double ; 8th and 10th magnitudes ; small, blue. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position =1 o** 40' nf I c Obs. I Diff. = 1° 47' ) ,, ,.a- ,, Distance = 1 5^462"^ | 5 Obs. | Diff. = i".o82l ^^^^ difficult. The small star bears only a very feeble illumination. Passy ; January 25, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 0° 16' nf Distances: is"-739 5 9MPiff- = o°39;|v,^diffieult. 5 Obs. 1 Diff. =o".769 A double star of the 5th class is also in the field sp, but it is unmeasurable with this instrument. Night fine. Mean Result. Position 0° 28' nf; Distance 15^600 ; Epoch 1825.03. and positions of4<5S double and triple stars, ^c. 105 No. DXIX. R. A. 6^^ 19" ; Decl. 52° 35' N. 229 (Bode) Aurigas ; Hist. Csel. 375 ; Struve, 226. Double; 8th and 10th magnitudes. The small star bears a very good illumination. Passy ; February 8, 1825 ; Seven feet Equatorial. Distance = 5".iSo [ 5 Obs, | DifF. = o".2i6. i HV ^^ Passy; March 19, 1825 ; Seven-feet Equatorial. ^' ' ' ' ^ V g^j^ ^^^ jQ^j^ magnitudes. Position = 48° 54' «p I 5 Obs. Distances 5". 162 | 5 Obs. Dlff: = o°/6^o} Very difficult. One third, perhaps one half, of the object-glass is not in use, through the interference of the timbers of the Observatory. Passy ; March 21, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 49* 58' np Distance = 5 ".357 5 Obs. 5 Obs. DifF. = 3° 15' I -n-n: ,. Mean Result. Position 49** 26' up; Epoch 1825.16; Distance 5".223 (15 Obs.); Epoch 1825.17. No. DXX. R. A. 6^ 19" ; Decl. 5° 24' N. Struve, 225 ; II. 89. Double ; 8th and 10th magnitudes ; small, blue ; and bears but the slightest illumination. Passy : January 2, 1825 ; Seven-feet Equatorial. Position = 50° 8' n/ I 7 Obs. I DifF. = 4° 48' > „ ^ A\ai^„u Distance= 6".8i i | 5 Obs. | DifF. = o" Xs^ ] ^^^7 difficult. Passy ; January 28, 1825 ; Seven-feet Equatorial. 8th and lOth magnitudes. Position = sf 47' «/ 1 7 Obs. I DifF.rr 4° 45' 7 Extremely difficult Distance=7". 117 | 5 Obs. | DiflF.= 0^.3 1 2 5 ^^tremeiy mmcuit. The dew deposited on the object-glass is excessively troublesome. MDCCCXXVI. p 106 Mr. South' s observations of the apparent distances No. DXX. continued. Mean Result. Position 50« 27^ »/(i4 Obs.); Distance 6".964 (10 Obs.); Epoch 1825.04. This star offers not the slightest ground for presumption of a change, the position in 1784 having been 50° 51' nf, and the distance (from the estimation in diameters) about 7". (H.) No. DXXL- c R. A. 6^ 22" ; Decl. 38° 40' N. Struve, 232 ; Hist. Csel. 208. Double; 9th and 11th magnitudes. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position = 42° 8' sf Distance = 3".200 8 Obs. i DifF. = 3° 48' ) ^ , , ,.0- ,, 5 Obs. I DifF. = o".697 ] Extremely difficult. Passy ; February 9, 1825 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position = 43° 44' */ 1 8 Obs. DifF. = 2° 30' 7 ..g. , Distance = 4".027 | 5 Obs. DifF. = 0^529 | ^^^y difficult. Stars admirably defined, and are as steady as possible. Mean Result. Position 42" 56^ sf {16 Obs.) ; Distance 3". 61 3 ; Epoch 1825.05. No. DXXII. R. A. 6^ 22" ; Decl. 5"* 5S' N. Struve, 231 ; III. 75. Double ; 8th and 12th magnitudes ; small, blue, and scarcely ■ — • bears the least illumination. Passy ; January 2, 1825 ; Seven-feet Equatorial. c Obs. I DifF. = 3° 45' 7 17 ^ 1 j'm 1 5 Obs. I DifF. = o".6oi i Extremely difficult. Position = 14° 24' np Distance = io".586 and positions of 4}58 double and triple stars, &c. 107 No. DXXII. continued. Passy ; February 5, 1825 ; Seven-feet Equatorial. 8th and ioth magnitudes. Position = 16° 27' np I 5 Obs. I Diff. = i° 26' J y ^j^ j Distance = 10 '.962 .| 5 Obs. | Dift. z= o".3i2 S ^ The small star is decidedly blue, and bears only a very feeble illumination. Mean Result. Position 15"* 25' np ; Distance io".774 ; Epoch 1825.04. Sir W. Herschel has no measures of this star. (H.) No. DXXIII. R. A. 6^22"; Decl. 11° 22' N. 145, 2 ; or Nova } Double ; 7th and 12th magnitudes ; small, blue. Passy ; February 5, 1825 ; Seven-feet Equatorial. Position = 85<»24'n/ 5 Obs. I Diff. = i°i6' | ^ . , ,.« ,^ Distance = i6".668 5 Obs. | Diff. = i".io6 J Excessively difficult. Passy ; February 9, 1825 ; Seven-feet Equatorial. 7 th and 10th magnitudes. Position = 8c» 2' «/ c Obs, I Diff.= i°4c' 7 ,, ^ , ..-. ,^ Distance = if. 097 5 Obs. \ Diff. = 0"% \ ^^^'^"^^^V ^«=«^'^- Mean Result. Position 85° is' nf; Distance i6*.882 ; Epoch 1825.09. No. DXXIV. R, A. 6^ 23" ; Decl. 22^ 15' N. Struve, 233 ; Mayer ; Triple ; A 7th, B 7j, and C of the 12th or 15th magnitudes. Measures of AB. Passy ; December 5, 1824 ; Seven-feet Equatorial. Position = 27° 14' sp | 5 Obs. I Diff. = 0° 40' ) Distance = SS'-^S^ I 5 Obs. | Diff. = ©'.793 > io8 Mr, South' s observations of the apparent distances No. DXXIV. continued. Passy ; December 31, 1824 ; Seven-feet Equatorial. 8th and 8 J magnitudes. Position = 27° lo' sv\ c Obs. I DifF. = o° 56' ) „! j c j j ^ j Distance = sz".784 ^ | 5 Obs. I DifF.= i".539 J ^ defined, and unsteady. Passy; January 8, 1825 ; Seven-feet Equatorial. 7th and 7f magnitudes. i''^^ J Distance = 53".oo8 j 5 Obs. I DifF. = o".793 Passy ; January 17, 1825 ; Seven-feet Equatorial. 8th and 81 magnitudes. Position = 270 8' *p I 5 Obs. DifF. = 1° 36' 7 „ , , Distance = 54".o38 | 5 Obs. DifF. = o".432 ] ^^^ ^"^^ Night very unfavourable j of A C no measures can be procured. Measures of A C. Passy ; December 5, 1824; Seven-feet Equatorial. 7th and 12th, or 15th magnitudes. Position = 59° 39' sf I 2 Obs I DifF. = 0° 18' i ^xcessivelv difficult Distance = 1' 46".s 1 1 ± single observation ] Excessively aimcuit. The star C bears no illumination : the distance is little better than conjecture. Mean Result. of AB. Position 27° 11' sp (15 Obs.) ; Epoch 1824.99 ; Distance 53".28o (20 Obs.) ; Epoch 1825.00. of AC. Position 59° 39' sf; Distance 1' 46".5H ; Epoch 1824.93. and positions 0/4,58 double and triple stars, ^c. 109 No. DXXV. R. A. 6^ 24°^ ; Decl. 41' 15' N. 145, 60 ; or Nova ? Double; 10th and 11th magnitudes. Passy; February 5, 1825 ; Seven-feet Equatorial. Position = \6° 2g' nf Distance = z^'.J^J 5 Sk'- I S-5= '°y \ Extremely difficult. 5 Obs. I DifF. = o*.745 ) ^ Passy ; February 11, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. c Obs. DifF. = o° 46' ) „ ^ , ..^ ,^ 5 Obs. Diff. = o".456 J Extremely difficult. Position =15° 36' nf Distances: 26*. 106 Passy ; March 26, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. Position = 16° 26' nf\ 5 Obs. j Diff. = 1° 18' Extremely difficult. Distance = 25".86i j 5 Obs. | Diff. = o".793 3 ' Mean Result. Position 16° 10' nf (15 Obs.); Distance 25". 6^6 (i5 Obs.) ; Epoch 1825.14, The measures of distance do not accord so v^ell as might be wished ; still the observations are so very difficult, that I scarcely dare to reject those of February 5. No. PXXVI. R. A. 6h 26- ; Decl. 41° 43' N. Struve, 234 ; I. 84. A very close double star; 9th and 10th magnitudes. A power of 303 with the Five-feet Equatorial distinctly separates the two stars, and 133 shows it double : it is ex- cessively difficult to measure ; bears magnifying but badly ; and although the night is tolerably fine, is unmeasurable with the Five-feet. Blackman-street ; January 31, 1824 ; Seven-feet Equatorial, Position = 3** co' nf\ c Obs. Diff. = i«> 30' ) ,, . , ..^ ,^ Distance = I".82o "^ | 3 Obs. | Diff. = o".48i } $^c«sively difficult. Position r: 5° 26' nf Position := 50 41' w/ Distance r: i".570 5 Obs. 5 Obs. 5 Obs. 1 10 Mr. South' s observations of the apparent distances No. DXXVI. continued. Passy ; Februaiy 6, 1825 ; Seven-feet Equatorial. DifF. =: 4° 42' With power 273 These stars are of a light blue colour ; they are very close, bear but very little illumination, and are not well defined under sufficient magnifying power, to separate their discs completely from each other. The first set of angles taken this evening were gotten with 273, but the attempt to observe the distances with that power, was altogether ineffectual. The night is very favourable. Mean Result. Position 4° 59' nf (15 Obs.) ; Distance i".664 (8 Obs) ; Epoch 1824.58. At the Epoch 1783.25 the position of this star was found 14" o' nf. The change in 41.23 years amounts to 9° 1', being at the rate of + o°.2 19 direct, or in the direction nf sp. This change is too great to arise from mere error of observation ; so that there is considerable probabiHty of this turning out a binary star, and it ought therefore to be kept in view. (H.) • No. DXXVII. R. A. 6^ 27'" ; Decl. 23° 19' N. Nova ; Double ; 9^ and 10th magnitudes, and bear but a very feeble illumination. Passy; February 12, 1825 ; Seven-feet Equatorial. Position = 68° 2' sf Distance ::= iS"«95* 5 Obs. I Diff. = 2° 52' 7 ,r _ ,.«: 1^ 5 Obs. I DifF. = o".769 j V^^ d^^^^l^- Passy ; February 19, 1825 ; Seven-feet Equatorial. 10th and 10| magnitudes. Night hazy. Mean Result. Position 67° 48" sf; Distance 15".905; Epoch 1825.12. and positions 0/4,58 double and triple stars, &c. 111 No. DXXVIII. R. A. 6^ sS"^ ; Decl. 31° 44' N. Nova; Double ; 8th and 11th magnitudes. Passy ; February 12, 1825 ; Seven-feet Equatorial. Position zz 6^° \o' nf c Obs. I DifF. = i° 52' 7t? • 1 j-n: 1* Distance = h\'.t^% 5 Obs. | DifF. = o".649 f Excessively difficult. 5 5 The accuracy of the observations is somewhat questionable. Passy ; March 29, 1825 ; Seven-feet Equatorial. 8th and 1 1th, or 12th magnitudes. Position = 640 29' „/| 5 Obs I DifF. = 0° 52' 7 Excessively difficult. Distances 1 19 .735 ±: single observation 3 ' The small star is so extremely obscure, that the distance here given may be liable to an error of five, or even six seconds. Mean Result. Position 64** 4' nf'. Distance i' 2o".69i ± ; Epoch 1825.17. No. DXXIX. R. A. 6^ 28™ ; Decl. 12° 23' N. Nova ; Triple ; A of the 7th, B of the 9th, and C of the 8th magnitudes. Measures of A B. Passy ; February 12, 1825 ; Seven-feet Equatorial. Position = 72° 48' sf I 5 Obs. I DifF. = 0° 57' 7 Distances 1' 32". 329 | 5 Obs. | DifF. = i".5is 3 * * Passy ; February 17, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes- Position =: 73° 5' sf 5 Obs. I DifF. = 00 53' Distance = i'" 3 r".66 1 5 Obs. | DifF. = i".i5o5 ? • • • Measures of A C. Passy; February 12, 1825 ; Seven-feet Equatorial. 7th and 8th magnitudes. Position = 80" 36' */| 5 Obs. I DifF. r: o» 51' 7 Distance = 3' 8".o79 | 5 Obs. [ DifF. = i".346 J * * * 112 Mr. South' s observations of the apparent distances No. D XXIX. continued. Passy ; February 17, 1825 ; Seven-feet Equatorial. 8th and 8^ magnitudes. Position = 8o° 55' */ Distance = 3' 7".747 5 Obs. 5 Obs. DifF. = 0° 51' ) DifF. = i".o58 3 Mean Result. of A B. Position 72° 56' sf\ Distance 1' 3i"-995 ; of A C. Position 80** 45' •?/; Distance 3' 7".9i3 ; Epoch 1825.12. No. DXXX. R. A. 6^ 29°" ; Decl. 59° sY N. Struve, 238 ; Double ; 9th and 1 2th magnitudes. Passy ; January 5, 1825 ; Seven-feet Equatorial. Position = 47° 6' sf Distance = 3".436 6 Obs. 5 Obs. Diff! = ©".529 5 Extremely difficult. Passy ; February 4, 1825 ; Seven-feet Equatorial. 9th and 12th magnitudes. The small star is blue, and will scarcely admit of the least illumination. Passy ; February 9, 1825 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position = 46° S^'sf S Obs. Diff. = 1° 38' | yery difficult. Distance == 4 .123 5 Obs. DifF. z= o".33o j ' Stars extremely well defined, and are unusually steady. Mean Result. Position 46° 48' 5/(17 Obs.) ; Distance 4".o63 (15 Obs.); Epoch 1825.07. and positions of 458 double and triple stars y &c. 113 No. DXXXI. R. A. 6^ ss"" ; Decl. 55'' 54' N. Struve, 243 ; 11- 72 ; Double ; 8th and 8 J magnitudes. Black man-street ; February 2, 1824 ; Five-feet Equatorial. Position = ,00 IS' nf I 5 Obs. Diff. =: i; 59' ) Satisfactory. Distance = 4 .832 | 5 Obs. Diff. = 1.105) Stars admirably defined, and as steady as possible. Night still very hazy. Passy ; January 20, 1825 ; Seven-feet Equatorial. 8th and 8f magnitudes. Position s=: 1 2° 1 3' n/ Distance = 4". 178 5 Obs. 5 Obs. iff = o" ^^'el ^^Slit unfavourable. Diff. = Diff. Passy ; Februaiy 6, 1825 ; Seven-feet Equatorial. 8th and 8? magnitudes. Position = 10° 23' nf 5 Obs. ( Diff. = 2° 1/ ^ Distance = 4".546 5 Obs. I Diff. = o'.3845 Mean Result. Position 10** 57' nf(i5 Obs.); Distance 4".5i9 (i5 Obs.) ; Epoch 1824.74. There is no change in this star in position, as a measure taken in 1782 makes it 11° o' sp or nf. The distance is only estimated in diameters. (H.) No. D XXXII. R. A. 6^ 33" ; Decl. f 49' S. Struve, 241 ; Hist. Csel. 267. Double; 10th and 11th magnitudes ; pale; ill defined stars, scarcely bearing the least illumination. Passy ; December 29, 1824 ; Seven-feet Equatorial. Position = 79: ^9'^P 6 Obs. I Diff. = 3° 5f' I Excessively difficult. Distance = 12 .731 S Obs. | Diff. = o .913 j ^ Great confidence must not be placed in the accuracy of these observations : the morning however is extremely favourable. MDCCCXXVI. q 1 14 Mr. South's observations of the apparent distances No. D XXXII. continued. Passy ; January 25, 1825 : Seven-feet Equatorial. lOth and 10|^ magnitudes. Position = 79° 48' sp I 6 Obs. DifF. =: 2«» 48' ) t7^.„^„i„ j;fl:^„u Distance= i2".484 ^ | 5 Obs. DifF. = o".]o5 \ Extremely difficult. Night remarkably fine. Mean Result. Position 79° 49' sp (12 obs.) ; Distance i2".6o7 (10 obs.) ; Epoch 1825.03. No. DXXXIII. R. A. 6^ 33"^ ; Decl. 25° 18' N. 6 Geminorum ; Struve, 242 ; VI. 73. Double; 4th and 10th magnitudes; small, blue; and does not bear a good illumination. Passy ; I>ecember 29, 1824 ; Seven-feet Equatorial. Position = 3° 51' «/ Is Obs. I DifF. = o® 40' \ ,. „, A\tfin»\* Distance = i' 5 1".788 \ 5 Obs. | DifF. = i" gz^ \ ^^^ ^^®*^"^** Passy ; February 6, 1825 ; Five-feet Equatorial. 4th and 11th magnitudes. Position =3 3^ 33' sf I 5 Obs. j DifF. = 0° 19' ) ,,_, j;fl:„,u Distance = V l\".^6e \ 5 Obs. | Diff. = o'.sji ] ^^ ^^^^^• Mean Result. Position 3** 42' sf\ Distance 1' 51" -577 ; Epoch 1825.04. Sir W. Herschel has given no measures of position for this star. The distance appears to have undergone no change. (H.) No. DXXXIV. R. A. 6^ 36°^ ; Decl. 22° 15' S. Nova ; Double ; 8th and 11th magnitudes. Passy ; February 17, 1825 ; Seven-feet Equatorial. Position =5 50 46' 5/ I 5 Obs. DiflF. = 2° 16' 7^^ • 1 j-o: 1* Distance = i8".404 | 5 Obs. Difi^. = i".i54 j Excessively difficult. Night hazy, and stars very unsteady. and positions of ^s^ double and triple stars y &c. 115 No. D XXXIV. continued. Passy ; March 28, 1825 ; Seven-feet Equatorial. 8th and 1 0th magnitudes. ion =520 58' ./ I 5 Obs. I Diff.=4° 47' \ Excessively difficult. ,nce=i8.ioo | 5 Obs. | Diff.=o'.72i 5 Observed when 1 1 hour west of the meridian. Position = Distance Passy ; March 29, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position =53° 30' sf I 5 Obs. I DifF. = 2° 20' 1 Extremely difficult Position =53« lo'sf \ 5 Obs. | Diflr.=2".36 ] ^^"^emeiy mmcuit. The first set was observed by twilight, without artificial illumination ; the st^rs being 40 minutes west of the meridian ; the last by the aid of the lamp, when 70 minutes west of it. Mean Result, (The angles taken on February 17 being rejected) Position 53^13' sf', (15 Obs.) ; Epoch 1825.23 ; Distance 18^252 ; Epoch 1825.17. No. DXXXV. R. A. e** 40- ; Decl. 75' So' N. Struve, 247 ; Hist. Casl. 365 ; Double ; 8th and 10th magnitudes. Passy ; January 5, 1825 ; Seven-feet Equatorial. Position ^66° H'n/I 5 Obs. Diff. = 1° 13' ) „ .._ ,, Distance = iz". 6^s \ 5 Obs. DifF. = o".48i } ^^^ *^*<^^^- Passy ; February 4, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position =65® 21' nf\ 5 Obs. Difi^. =1° 23' ) Distances 1 2".44i | 5 Obs. Difi^. =0". 697 j Mean Result. Position 65"" 47' «/; Distance 12".538 ; Epoch 1825.05. 116 Mr. South' s observations of the apparent distances No. D XXXVI. R. A. 6^ 41" ; Decl. 39° 5' N. 59 Aurigse ; Struve, 248 ; IV. 102. Double; 6th and 15th magnitudes. Passy ; January 8, 1825 ; Seven-feet Equatorial. Position =48° ig' sp c Obs. Diff. = i° 30' ) ^j „ . , ,.«- ,^ Distance = t i".6?i ^ 5 Obs. Diflr. = ,".082 \ Expressively difficult. The small star is a mere point, and will not bear any illumination ; the night is now tolerably good. In 1783, the measures were 50° 3' npy and 23" -50 ; so that this star has undergone no material change. ( H.) No. DXXXVII. R. A. 6^ 42" ; Decl. 23° 55' S. Nova; Double ; 7th and 11th magnitudes; small, blue. Passy ; February 23, 1825 ; Seven-feet Equatorial. Position = 1 1° 54' n jo Distance = 30". 908 5 Obs. 5 Obs. Diff: = I''.os8}^^^^^<="^*- Passy ; March 2, 1825 ; Seven-feet Equatorial. 7th and 11th magnitudes. Position = 11° 49' np Distance = 29".873 5 Obs. 5 Obs. Diff! = o°.865 } Extremely difficult. Passy ; March 18, 1825 ; Seven-feet Equatorial. 7th and 11th magnitudes. Distance = 30*. 134 [ 5 Obs. | Diff. = i''.370. Excessively difficult. The small star becomes invisible under the slightest illumination. Mean Result. Position 11^ 51' np (10 Obs.); Epoch 1825.15; Distance 3o".305 (15 Obs.); Epoch 1825.17. and positions 0/458 double and triple stars, &c. 117 No. DXXXVill. R. A. 6^ 42° ; Decl. 23° 55' S. Nova ; Double ; 8th and 9th magnitudes ; small, blue. Passy ; February 18, 1825 ; Seven-feet Equatorial. Position = 860 50' nf \ 5 Obs. [ Diff. = o^ 43'. Difficult. ' The night is become cloudy ; observations of distance are impracticable. Passy ; February 23, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 86° 38' nf 5 Obs. I DifF. = 1° 1 1' | „^^ a\4K..,u Distance = zy'^Syg 5 Obs. Diff. = i".i78i ^"^ ^^^^^^*- Passy ; March 2, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Distance = zf.JZZ \ 5 Obs. \ Diff, = o".84i. Very difficult. Mean Result. Position 86° 44' nf; Epoch 1825.13 ; Distance 27''.8o6 ; Epoch 1825.15. No. D XXXIX. R. A. 6^ 43"^ ; Decl. 46° 47' N. Struve, 250 ; Double ; 9th and 12th magnitudes. Passy ; January 8, 1825 ; Seven-feet Equatorial. Position =: 60° 53' sv 1 c Obs. I Diff. = i° 34' ) ^ ^ , ,.«- ,^ Distance = 8".34 5 Obs. | Diff. = o".8 i; \ Extremely difficult. The small star is very faint, and bears but the most feeble illumination. Passy ; February 5, 1825 ; Seven-feet Equatoiial. 9th and 12th magnitudes. Position = 60° 19'* p I 5 Obs. 1 Diff. = 2° ic' 7 i? *. ^1 j-ie 1* Distance:=8".i29 ^ | 5 Obs. Diff. = o-.elj \ Extremely difficult. Mean Result. Position 60° 36' sp ; Distance 8''.229; Epoch 1825.08. 118 Mr, South's observations of the apparent distances No. DXL. R. A. 6^ 47°^ ; Decl. 3o° ii' S. ^* Canis Major ; Struve, 252 ; V. 65, Quadruple; A of the 6th, B of the 10th, C of the 12th, and D of the 15th magnitudes. Measures of A B. Passy ; January 8, 1825 ; Seven-feet Equatorial. Position = 58° 11' «/l 5 Obs. DifF. = i° 35') „ • , j-a ,. Distance = 45".876± | i Obs. -i J Excessively difficult. The night is become so unfavourable, that no more observations can be gotten. Passy ; January 17, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position =. 57° 43'^/ 1 5 Obs. I Diff. = 1° x' ) ^^^^^^^ ^^^^^^^ Distance = 44".775 | 5 Obs. | Diff. = o".9i3 ) ' Passy ; February 9, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Distance = 4S"-i*3 | 5 Obs. | Diff. = z".o\^. Extremely difficult. Measures of A C. Passy ; January 17, 1825 ; Seven-feet Equatorial. 6th and 12th magnitudes. Position = 860 , ' ,p 5 Obs. I Diff. ^ 3^ f' \ Excessively difficult. Distances 52 .188 2 Obs. | Diff. = o".36o5 ^ The observations of distance very precarious, and of the pair A D no measures can be obtained. Night remarkably fine; but the dew on the object-glass is exces- sively troublesome. Passy ; February 9, 1825 ; Seven-feet Equatorial. 6th and 12th magnitudes. Measures of A D. Passy ; February 9, 1825 ; Seven-feet Equatorial. 6th and 15th magnitudes. Position = 84O 44' s p Distance = 2' 8".36o ± 2 Obs 2 Obs ; I gi|- '^",^'A Excessively difficult. Observations probably a little inaccurate ; the small star can only be seen by glimpses. and positions of 458 double and triple stars y ^c, 119 No. DXL. continued. Mean Result, of A B. Position 57* 5/ sf {10 Obs. ) ; Epoch 1825.03 ; Distance 45*.033(ii Obs.); Epoch 1825.05. of AC. Position 85° 42' sp (10 Obs.); Distance b^I'.qsi (7 Obs.); Epoch 1825.07. of A D. Position 84° 44' sp{^ Obs.) ; Distance 2' 8". 360 ± (2 Obs.); Epoch 1825.10. A considerable change seems to have taken place in the position of these stars since 1783, in which year the measures were : Position 64° 12' sf; Distance 44''.93. The difference, 6° 1 5', is much more than could be fairly attributable to error of observation in a star of the 5th class, except under very difficult circumstances. (H.) No. DXLI. R A. 6^ 5o»» ; Decl. 22° 24' S. Nova ; Triple ; A of the 8th, B of the 9th, and C of the 10th magnitudes. Measures of AB. Passy ; February 21, 1825 ; Seven-feet Equatorial. Position = 46° 6' n/ 1 s Obs. | Diff. = i° 40' ) T^-ir 1* Distances 2^.917 \ 5 Obs. \ Diff. = i".7s4 ) ^^^^^*- Passy; March 17, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position = 470 39' nf\ 5 Obs. I Diff. = 2° 52' 7 „ , , ..«. ,^ Distance = 2^.277 | 5 Obs. j Diff. = ."J^^ | Extremely difficult. The small star bears scarcely any illumination. 120 Mr, South' s observations of the apparent distances No. DXLI. continued, Passy ; Measure of AC. February 21, 1825. Position = 32° lo' ±: sf; single observation. Night so unfavourable, measures entitled to confidence cannot be procured. Mean Result. of A B. Position 46° 52' w/; Distance 24".09 7; Epoch 1825.16. of A C. Position 32° 10' sf± ; single observation. No. DXLII. R. A. 6"^ 51" ; Decl. 53° 1' N. Struve, 25s ; I. 69. Double ; 8|- and S\ magnitudes. Blackman-street ; February 2, 1824 ; Five-feet Equatorial Position = 660 35' sf I 5 Obs. I DifF. = !<> o' ) „ . Distance = f.g^S \ 5 Obs. ( DifF. = o".4i i j ^^^^ S®®^* Stars beautifully defined, and very steady ; but the night is hazy. Passy; February 11, 1825 ; Seven-feet Equatorial. 8th and 8J magnitudes. Position = 67® 14! sf\ 5 Obs. Distance z: 3".785 \ 5 Obs. DifF. = i*> 44' 7 DifF. = i".0343 Mean Result. Position 66° 6^' sf\ Distance s".89i ; Epoch 1824.59. This star has undergone a change of position so consider- able, as to entitle it provisionally to a place among the binary or connected stars. At the Epoch 1782.87, an observation of Sir W. Herschel, noted as " very exact,'' makes the position 77° 24' sf. The change is — 10° 30' in 4iV.'jQ, giving an annual motion of — 0^.252, in the direction np sf or retrograde. This star therefore merits the assiduous attention of astronomers. (H.) and positions of 4iS8 double and triple stars y &c. 121 No. DXLIII. R. A. 6^ 54" ; Decl. 22° 25' S. Nova ; Double ; 9th and 9^ magnitudes. Passy ; February 21, 1825 ; Seven-feet Equatorial. Position = i« 34' «;> I 5 Obs. I Diff. = o° 50' ) y difficult Distance = i' 3o",836 ] 5 Obs. | DifF. = ©".6495 ^^^ tumcuit. Stars very unsteady. Passy ; March 10, 1825 ; Seven-feet Equatorial. lOth and lO^ magnitudes. Position =1** ij' np Distance =: i' 3 2". 130 5 Obs. 5 Obs. Dlff: = ?'.'ozt Extremely difficult. Passy ; March 28, 1825 ; Seven-feet Equatorial. 9^ and 10th magnitudes. Distance = 1' 3i".329 | 5 Obs. | DifF. = 2". 16^. Extremely difficult. Mean Result. Position I*' 25' np (10 Obs.); Epoch 1825.16; Distance 1' 3i".432 (15 Obs.); Epoch 1825.16. No. DXLIV. R. A. 7** 2" ; Decl. 22° 35' N. Nova ; Double ; equal ; each of the 9th magnitude, and bear a very good illumination. Passy ; February 12, 1825 ; Seven-feet Equatorial. Position = 50® 54' sp or nf J 5 Obs. Distance = 9''.223 j 5 Obs. DifF. = 2" 28' ) DifF. =o".4565 Passy ; February 17, 1825 ; Seven-feet Equatorial. Equal ; each of the 9th magnitude. Position = 48° 48' nf or sp c Obs. 1 DifF. = 1° 8' 1 .r ^ * j Distance = 9''.6j2 "^ 5 Obs. | DifF. = o".384. j ^"^ ^^^^^^X* Passy ; February 24, -1825 ; Portable Transit. Observed R, A. of the northern or following star = 7'' 1' 33".79. Mean Result. , .,_~ Position 49** 5i' sp or nf; Distance 9^.427 ;*fepoch 1825.13. MDCCCXXVI. r .32 Mr. South' s observations of the apparent distances No. DXLV. R. A. 7^ 5" ; Decl. 73° 23' N. Struve, 256; 1790, 387 ; Double ; 8^ and 9th magnitudes. Passy ; January 6, 1825 ; Seven-feet Equatorial. Position = 8° 13' n/l 5 Obs. | DifF. = 0° 58'. . . . Passy ; February 4, 1825 ; Seven-feet Equatorial. Position = 8» 52' nf Distance = ^i'.z^i 5 Obs. 5 Obs. DifF. =0053' > DifF. =o".48i j Passy ; February 6, 1825 ; Seven-feet Equatorial. 8J and 9th magnitudes. Distance = 3o".879 | 5 Obs. | DifF. = ©".889. Mean Result, Position S'' 32' nf\ Epoch 1825.05 ; Distance si".o85 ; Epoch 1825.09 No. DXLVI. R. A. 7*" 10" ; Decl. 31° 48' N. Nova ; Triple; A S-f-, B 10th, and C of the 11th magnitudes. Measures of A B. Passy; February 12, 1825 ; Seven-feet Equatorial. Position = 89° 29' np\s Obs. Diff. z= o° 37' ) ,, „, j:ffl^„u Distance = i' 19^350 | 5 Obs. DifF. = o".6oi } ^^^ ^'^*^''^*- Passy; February 17, 1825 ; Seven -feet Equatorial. 8| and 10th magnitudes. Position = Zf ly np I 5 Obs. I Diff. = 0° 32- J Extremely difficult. Distance = 1 19 .850 [ 5 Obs. | Diff. = i".202 j ^ Measures of A C. Passy; February 12, 1825 ; Seven-feet Equatorial. 8^ and 11th magnitudes. Position = 200 5/' «/| 2 Obs. I Diff. =. o; 38' J Excessively difficult. Distance = 2' 22".637 j 2 Obs. ] Diff. = o".793 ) ' Measures to be regarded with some distrust. and positions of 4f5S double and triple stars ^ ^c. 123 No. DXLVI. continued. Passy ; February 17, 1825 ; Seven-feet Equatorial. 9th and 12th magnitudes. Position = 20° 40' nf; single observation. The night is become so hazy that no more measures can be obtained. Mean Result. of A B. Position ^of" ^^' np\ -Distance 1' 19". 600 ; Epoch 1825.12. of AC Position 20° 47' nf{ 3 Obs.); Epoch 1825.12 ; Distance 2' 2 2^.63 7 (2 Obs.); Epoch 1825.11. No. DXLVII. R. A. 7^ 15" ; Decl. 20° 48' N. Struve, 260 ; III. 48 ; Double; 8th and p^jnagnitudes. Blackman-street ; March 12, 1824 ; Five-feet Equatorial. Position = 50° 51' »/j 5 Obs. Diff. = 2° ii' | Distance = 6".^ 11 15 Obs. Diff. = o".505 3 Blackman-street; March 31, 1824: Five-feet Equatorial. Sth and 10th magnitudes. Position = sf 37' nf\ 5 Obs. Diff. = 3° 43' I Measures very difficult. Distance = 6 '.521 ) 5 Obs. Diff. = 0.5695 ^ Mean Result, Position 50*^44'^/; Distance 6".5 16; Epoch 1824.21. There is a notable alteration perceivable in the position of this star. A measure on the ist of January, 1783, marked " very exact," makes the angle 43° 54' nf, and the distance at the same time was found to be 6".25. The change of position amounts to — 6° 50', being — o°.i 66 per annum, retrograde. Future observations must decide on the reality of this motion, and whether this is entitled to more than a proTisional place among the Binary stars. (H.) i«4 Mr. South' s observations of the apparent distances No. DXLVIII. R. A. 7^ I?"" ; Decl. 22° 30' N. Struve, 261 ',N. 66\ Double ; vrti and 10th magnitudes. Passy; January 29, 1825 ; Seven-feet Equatorial. Position = 6° 3' «p I 5 Obs. DifF.=o° 53' 1 y . Distance=36".oo8 | 5 Obs. DifF. = i".S39 5 ^^ ^' Night remarkably fine. Passy ; February 5, 1825 ; Saven-feet Equatorial. 7th and 10th magnitudes. Position = 50 42' np 5 Obs. | DifF. = 0° 42' ^ Distance = 35".23 1 '"' '""" 5 Obs. I DifF. = i".o345 Mean Result. Position 5° 52' np ; Distance 35" 619 ; Epoch 1825.09. , An estimation in 1783 made the angle 1** or 2° np, and a measure of distance at the same time gave 34". 65. It is to be presumed therefore that this star is liable to no notable alteration in either respect. ( H. ) No. DXLIX. R. A.- 7^ 20- ; Decl. 14^ 13' N. Struve, 264 ; Hist. Csel. 314 ; Triple ; A 6th, B 10th, and C of the 7th magnitudes. Measures of A B. Passy ; January 6, 1825 ; Seven-feet Equatorial. Position = 30° 4.' nf\7 Obs. DifF. = c° 58' ) ^ ^ 1 j-^ 1. Dislance = rJs "^ | 5 Obs. Diff. = o".649 1 ^""'''"^'^^ ^^®^"^*- Passy; January J 9, 1825 ; Seven -feet Equatorial. 6th and 11th or 12th magnitudes. Position = 40° 33' nf\ 5 Obs. DifF. = 5° 43') Pxcessivelv difficult Distance = 8".oi4 j 5 Obs. DifF. = o".72i j excessively ditticult. and positions 0/^458 double and triple stars ^ &c» 125 No. DXLIX. continued. Measures of A C. Passy; January 6, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position =39° 36' *y Distance = 1' 5o".988 5 Obs. 6 0bs. ifF.=o° 33' ) ifF. = i".oio5 DifF.= DifF. Passy ; January 17, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position = 39° 35' «/ 5 Obs. DifF. = o'' 49' | Distance = i' 52".207 6 Obs. DifF. = i".202| Of A B no measures can be obtained, although the night is beautifully fine ; the object-glass cannot be kept one minute free fi'om moisture. Passy ; March 26, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. Distance = 1' si".6g9 | 5 Obs. | DifF. = i".io6. Mean Result. of A B. Position 39° 41' ^/ (12 Obs.) ; Distance 7" -999 ; Epoch 1825.03. of A C. Position 39° 35' sf (10 Obs.); Epoch 1825.03 ; • Distance 1' 51". 62 7 (17 Obs.); Epoch 1825.09. No. DL. R. A. 7^ so"*; Decl. 18° 8'S. Struve, 263 ; Hist. Csel. 281 ; Double ; 7^ and 8th magnitudes : small, blue. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position 26° 22' sf | 5 Obs. | DifF. = i° 12 Passy ; January 17, 1825 ; Seven-feet Equatorial. 7f and 8th magnitudes. Position =26° I'sf ] 5 Obs. Distance =40". 1 92 | 5 Obs. DifF.= o°52' ) DiflF. = o".937 5 Passy ; January 28, 1825 ; Seven-feet Equatorial. 7h and 8th magnitudes. Distance = 39".899 ] 5 Obs. | DifF. = i".25o. Very unsteady. Mean Result. Position 26** iQ* sf; Epoch 1825.02 ; Distance 40". 041 ; Epoch 1825.05. 126 Mr. South's observations of the apparent distances No. DLL R. A. 7*^ 2i°» ; Decl. 5° si N. Struve, 265 ; Hist. Csel. 261 ; Double ; 9th and 12th magnitudes ; small, blue, and bears but a very slight illumination. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position = 24° 58' sp I 6 Obs. I Diff. = i« 55' ) r- . 1 j-n: , Distance = 4".686 J 5 Obs. | DifF. = o".456 \ Extremely difficult. Passy ; January 19, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 240 32' *j3 I 5 Obs. Distance = 4".5i3 J 5 Obs. DifF. = 2«> 48' ) ,, ..«: ,^ DifF. = i".49i J Very difficult. Mean Result. Position 24° 46' sp (ii Obs.); Distance 4".599 (lo Obs.) ; Epoch 1825.03. No. DLII. R. A. 7^ 27' ; Decl. 23° 4' S 145, 19 ; or Nova .? Double ; 7th and 7^ magnitudes. Passy ; December 29, 1824 ; Seven-feet Equatorial. Position = H** SZ' np\S O^s. [ DifF. = o° 46' \ Distance = 8 ".860 | 5 Obs. Diff. = ©".408 j Passy ; December 31, 1824 ; Seven-feet Equatorial. 8th and 8^ magnitudes. Position = 14° 54' np 5 Obs. I Diff. =0° 57' ) „ unsteady Distance = 9".683 5 Obs. | Diff. =o".625 ] ^^^ unsteady. Passy ; January 28, 1825 ; Seven-feet Equatorial. 7th and 71 magnitudes. Distance = 8".477 | 5 Obs. | Diff. = i".394. Rather difficult. Stars neither well defined or steady. The dew on the object glass is intolerably troublesome. The water precipitated on the instrument is trickling from it, falls upon my face during the observations of high stars, and is extremely annoying. Thermometer stands at 28°. Mean Result. Position 14° 53' np (lo Obs.); Epoch 1825.00 ; Distance 9".oo7 (15 Obs.) ; Epoch 1825.02. and positions 0/4,58 double and triple stars, &c. 127 No. DLIII. R. A. 7^ 28- ; Decl. 14° 6' S. 34 (Bode) Off. Typograph. ; Struve, 268 ; II. 63 ; Double ; 8th and 8^ magnitudes. Placed in a telescopic constellation, I count more than 70 stars in the field. Passy ; December 29, 1824 ; Seven-feet Equatorial. Position = 32° 48' np 5 Obs. I DifF. = 0° 23' ) Distance = 7".383 5 Obs. | DifF. = o".529> A minute or two to the north of this star, and following it a few seconds of time, will be found a double star of the 5th or 6th class j and about the same declination as this last-named star, by sweeping a few minutes in right ascension, a double star of the 4th class (8th or loth magnitudes) will be seen in the field. Passy; January 17, 1825; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 33° 52' np I 5 Obs. I DifF. = 1° 55' \ Distance = 7''.492 | 5 Obs. | DifF. = o".6oi ) • . ^ . • • Mean Result. Position 33° Qo' np; Distance 7*.437 ; Epoch 1825.02. This star has undergone no material change in position or distance since Sir W. Herschel's observations in 1783, which made it 30*" 12' 71 p, and 6 or 7" by estimation of diameters. (H.) No. DLIV. R. A. 7** 28°^; Decl. 14° 7'S. Nova ; Double ; 8th and 15th magnitudes. The large star precedes the second star of 34 (Bode) Off. Typogr. 32 seconds of time, and is about 39 seconds to the south of that star. Passy; March 12, 1825 ; Seven-feet Equatorial. Position = 54° 37' n/ 1 c Obs. I Diff. = i® ig' } „ . , ,.^ . Distance = 2S".355 I 5 Obs. | DifF. = i".i54 J Excessively difficult. The small star will neither bear illumination nor magnifying power, Observa* tions were made with 105 : with 179 I could not obtain any measures. is8 Mr. South' s observations of the apparent distances No. DLIV. continued. Passy ; March 17, 1825 ; Seven-feet EquatoriaL 8th and 15 th magnitudes. Position = 54° 56' nf | 3 Obs. | DifF. = 3° 47'. Excessively difficult. • Measures of distance cannot be procured ; the small star will not bear the slight- est illumination. Observed with 105 j with 179 the small star was invisible. The accuracy of the results is I fear somewhat questionable. Passy ; March 23, 1825 ; Seven-feet Equatorial. 8th and 15th magnitudes. Position = 54® 37' nf I 5 Obs. Distances: 2o".i97 \ 5 Obs. Diff! = °".to4 1 E^c^"^^<^V difficult. Observed with the ordinary power of 179, on the meridian. Night cloudy. Stars of considerable southern declination are alone visible, but they are unusually bright, and tolerably steady. Mean Result. Position 54° 41' nf(i3 Obs.); Distance 2o".276(io Obs.); Epoch; 1825.20. No. DLV. R. A. 7' 28" ; Decl. 14° 4' S. Nova ; nf 34* Bode Off. Typograph. Double ; Yt and 8th magnitudes. Passy ; December 29, 1825 ; Seven-feet Equatorial. Position = 41° 52' sp Distance = 1' 34". 5 29 6 Obs. 5 Obs. DifF. = 1° 10 DifF. = I ".05 8 It is the double star first alluded to in the observations of 34 Bode Off. Typog. j and its smaller star has nearly the same R. A. as the larger star of 34 Off. Typog. Passy; December 31, 1825 ; Seven- feet Equatorial. 8J and 9th magnitudes. Position = 42° 22' * p 6 Obs. DifF. = 0° 36' 1 j. , difficult Distance = i'.34".933 5 Obs. DifF. = o".625 j ^^^'^^^ tumcult. 6 Obs. 5 Obs. Night very unfavourable. Mean Result. Position 42** 11' sp (12 Obs.); Distance 1' 34".73i (10 Obs.); Epoch 1825.00. and positions 0/^458 double and triple stars ^ &c. 129 No. DLVI. R. A. y^ 28" ; Decl. 65° 34' N. Struve, 267; P. VII. 159. Double ; 9th and 9^ magnitudes. Passy ; January 5, 1825 ; Seven-feet Equatorial. Position =: 85° 58' «/ 1 5 Obs. | DiiF. z= i' 20' ) Distancezz i6".285 | 5 Obs. | DifF. =z o".48i j • • • • Passy; February 4, 1825; Seven-feet Equatorial. 9th and 9? magnitudes. Position = 85° 28' sp Distance = i6".o66 5 Obs. 5 Obs. Diff. = 1° 2/ > Diff. = o".4o85 Stars very steady. Thermometer stands at 2y**.$. Wind very high. Mean Result. Position 85° 43' w/; Distance i6".i75; Epoch 1825.05. No. DLVII. R. A. 7^ 29" ; Decl. 14° 3' S. Nova ; Double ; 8th and loth magnitudes ; small, blue. Passy ; March 10, 1825 ; Seven -feet Equatorial. Position = 66° 38' np I 5 Obs. | Diff. = 1° 25' \ Distance = i' 6".225 | 5 Obs. Diff. = o".865 j • • • • The larger star of this double star follows the first of 34 (Bode) Off. Typogr. i' 2".3 of time, and is to the north of that star about 2' 47". Passy ; March 12, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = Sy** $' ^P \ 5 Obs. j Diff. = 0° 41') ^p^ Distance s= 1' 6".488 J 5 Obs. | Diff. = o".793 1 • • • • Mean Result. Position 66° 51' np ; Distance 1' 6".sg6 ; Epoch 1825.19. MDCCCXXVI. s ISO Mr. South's observations of the apparent distances No. DLVIII. R. A. 7^ SS"^ ; Decl. 3° 6' S. Struve, 271 ; Hist. Gael. 275. Double ; 9th and 10th magnitudes. Passy ; January 2, 1825 : Seven-feet Equatorial. Position =31° 36' sp | 5 Obs. I DifF. = 1° 22' \ ^.~ . , Distance = 20". 223 | 5 Obs. | DifF. - i".oio j ^^"^^""* Passy ; January 19, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 32° 13' «;? 5 Obs. I DifF. = 1° 43' ) ,,„ , j; Distance = 19". 261 5 Obs. \ DifF. r= d'.e^j] ^^^ ^ Passy ; January 28, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Distance =: 20". 173 | 5 Obs. 1 DifF. = 0^962. Very difficult. The stars are not steady j and the deposition of moisture on both surfaces of the object-glass is so copious and rapid, that although well wiped off, before the instru- ment can be replaced upon the star it re-collects, and compels me to discontinue the observations ; a circumstance much to be regretted, for the night is beautifully clear. Thermometer in the Observatory stands at 28°. Mean Result. Position 31* 54' sp (lo Obs. ) ; Epoch 1825.03 ; Distance 19".886 (15 Obs.) ; Epoch 1825.04, No. DLIX. R. A. 7^ 34" ; Decl. 28° 28' N. Pollux ; Struve, 274 ; VI. 42 ; Triple ; A 2nd, B 15th, and C of the 20th magnitudes. Measures of A B. Passy ; February 5, 1825 ; Seven-feet Equatorial. Position = 170 13' ±n/l c Obs. I DifF. = o" 21' ) „ • , a-oz 1. Distance = 3* 1/.469 ± | 5 Obs. | Diff. = 2".885 ] Excessively difficult. Observations liable to some slight error. and positions of4,sS double and triple stars, ^c. 131 No. DLIX. continued. Passy ; February 9, 1825 ; Seven-feet Equatorial. 2nd and 15th magnitudes. Position = 17° 27' nf± f c Obs. I DiiF. = i° ii' ) „ • i j-a: i*. Distance := 3' I5''.96i ± [ z Obs. I Diflr. = o".sSi\ ^^^'"'^'^y ^^^"^*- Results probably a little inaccurate. Measures of A C. Passy ; February 5, 1825 ; Seven-feet Equatorial. 2nd and 20th magnitudes.^ Position = 24** 6' n/ 1 2 Obs. | Diff. r= o*» 43'. Excessively difficult. The star C will not bear even the least illumination. No observations of distance can be gotten ; but by estimation, it is about two-thirds of the distance from A, that B is. The night is remarkably fine ; indeed on no other can either of the stars B or C be seen with this instrument. Passy ; February 9, 1825 ; Seven-feet Equatorial.] 2nd and 20th magnitudes. Position = 23° 25' nf\ 5 Obs. | DifF. 3° 57'. Excessively difficult. Of C no distances can be procured. The night is unusually fine, but the star will not bear the slightest illumination. Mean Result. of A B. Position 17** 20' nf {10 Obs.); Distance 3' i8'',467 (7 Obs.); Epoch 1825.10. of A C. Position 23° 37' w/(7 Obs.) ; Distance (estimated) 2' i2",3i2 + ; Epoch 1825.10. The position of the nearer star in 1783 was 24° 28' nf, differing only 51' from the present measure. (H.) 132 Mr. South's observations of the apparent distances No. DLX. R. A. 7^ 37" ; Decl. 29° 13' N. Struve, 279 ; V. 67. Double ; 6th and 12th magnitudes. Passy ; January 6, 1825 ; Seven- feet Equatorial. Position = 89° 22' np Distance = i' 29''. 821 Passy ; January 25, 1825 ; Seven-feet Equatorial. 6th and 1 2th magnitudes. Position = 89O 21' np I 5 Obs. DiiF. = 1° 36' | p.^.,.^ ,„ ..-.^ ,^ Distance = /3i".290 I 5 Obs. DifF. = 2".284] Extremely difficult. Passy ; March 26, 1825 ; Seven-feet Equatorial. 6th and 12th magnitudes. Distances: i' 3o".684 | 5 Obs. | DitF. = o".9i3. Extremely difficult. Mean Result. Position 89° 22' np (10 Obs.) ; Epoch 1825.04 ; . Distance 1' 3o".598 (15 Obs.) ; Epoch 1825.10. There is a doubt as to the identity of the star here mea- sured with V. 67. (H.) No. DLXI. R. A. 7^ 41" ; Decl. 25° le' S. Nova ; Double ; 10th and 11th magnitudes. Passy ; February 19, 1825 ; Seven-feet Equatorial. Position = 8-7° 45' nf I 5 Obs. 1 Diff. = 1° 48' > ^j ^ . , ,. _ , Distances o".7A ? Obs. DifF. = i".j22 Excessively difficult. Distances 51 .744 | 5 Obs. | DifF. = 1 .3223 Neither star bears sufficient illumination. Passy ; February 21, 1825 ; Seven-feet Equatorial. 10th and 11th magnitudes. Position rz 880 15' n/ 1 5 Obs. 1 DifF. = 0° 27' ) „ . , ..^ . Distance = 49".990 | 5 Obs. } DifF. = o".962 \ Excessively difficult. The star B is double of the 2nd class : its small star is about 35° sp, and distance perhaps 5 seconds ; it will not bear the slightest illumination. The measures of A B, particularly those of distance, are precarious. and positions 0/4,58 double and triple stars ^ ^c. 133 No. DLXI. continued. Passy; March 26, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. Distance = 5o".96o | 5 Obs. | DifF. = i".iS4. Excessively difficult. Mean Result. Position 88° o' nf {10 Obs.); Epoch 1825.13 ; Distance 50^.898 (15 Obs.); Epoch 1825.17. . No. DLXII. R. A. 7' 49" ; Decl. 79° 59' N. Nova ; Double ; 9th and 9 J magnitudes. Passy ; February 11, 1825 ; Seven-feet Equatorial. Position = 80° 12' nf\ c Obs. I DifF. = o« 27' ) ,^ Distance = 2i".409 | 5 Obs. | DifF. = d'.^^zz] ^^"^ ^ood. These stars bear a very good illumination : their circumpolar situation allowing them to be well observed throughout the year, and their position, (so near the per- pendicular,) rendering them susceptible of the most accurate measures, they would 'be admirably adapted for parallax observations. Passy; February 17, 1825 ; Seven-feet Equatorial. 9^ and 10th magnitudes. Position = 79« 58' nf I 5 Obs. I DifF. = 1O43' > ,, . ^ Distance = 2 1".47 1 | 5 Obs. | DifF. = o".456 \ ^^^ satisfactory. Mean Result. Position 80° 5' nf; Distance 2i".44o ; Epoch 1825.12. No. DLXIII. R. A. 8^0" ; Decl. 19° 18' S. Nova ; Double ; 6th and 7th magnitudes. Passy; March 21, 1825 ; Seven-feet Equatorial. Position = 34° ly'nf I 5 Obs. I DifF. = 0° 41' 7 ,, , . Distance = 2' I3".426 | 5 Obs. | DifF. = i".oio] ^^^ ^^^^y- Passy ; March 28, 1825 ; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 34° 22' n/ 1 s Obs. DifF. = qO 37' 7^, ,, ^ , Distance = 2' i3".979 | 5 Obs. DifF. = 2".043 ] Tolerably steady. Mean Result. Position 34" 20' sp; Distance 2' 13". 702 ; Epoch 1825.22. 134 Mr, South' s observations of the apparent distances No. DLXIV. R. A. 8^ 2" ; Decl. i'* 48' N. Struve, 290; Hist. Gael. ^6s. Double ; equal ; each of the 10th magnitude. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position = 68° 37' np or «/| 5 Obs. I DifF. = o« 30' 1 y difficult Distance = 33".639 | 5 Obs. | DifF. = o".889 | ^^"^^ difficult. Neither star bears a good illumination. Passy ; January 25^ 1825 ; Seven-feet Equatorial. lOth and lOf magnitudes. Position = 68° 29' no I c Obs. I DifF. = 1° 18' ) ,r ^, j:n;^„i. Distance =i33".6o3 | 5 Obs. 1 DifF. = o".962} ^^"^ ^^®^"^*- Mean Result. Position 68* 35' np or sf; Distance 33". 621 ; Epoch 1825.03. No. DLXV. R. A. 8»» 12" ; Decl. 42° 34' N. Struve, 294 ; Hist. Gael. 54 ; Double; 7th and 10th magnitudes. Blackman-street ; March 13, 1824 ; Five-feet Equatorial. Position = 74° s' «/ I 5 Obs. I DifF. = 0° 52' ^ ^^^^ .. -^ . Distance = i' i2".3^i | 5 Obs. | DifF. = o".885 j ^^^7 difficult. Passy ; January 25, 1825 ; Seven-feet Equatorial. 7th and Qf magnitudes. Position = 75° 31' */ 5 Ohs. I Diff. = 0° 29' 7 ^ diffirnlt Distance = i' i3".8oi 5 Obs. | DifF. = o".84i J ^^^y difficult. Passy ; February 3, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. Distance = i' \z".gS9 I 5 ^bs. | DifF. = o".72i. Very difficult. Mean Result. Position 74° 48' sf (10 Obs.); Epoch 1824.59 ; Distance 1' 13^040 (15 Obs.) ; Epoch 1824.75. and positions of 4;58 double and triple stars , &c. 135 No. DLXVI. R. A. 8^> 15" ; Decl. 28^ 26' N. Cancri ; Struve, 296 ; VI. 109. Double; 7th and 12th, or 15th magnitudes, Passy ; Jaauary 29, 1825 ; Seven-feet Equatorial. Position = 68° o' nf± ; single Observation. The night, which had been remarkably fine, cloudless, and unusually favourable for delicate observations, on account of the extreme steadiness of the stars, which enabled me to keep them bisected by the wires as long as I pleased, suddenly be- came bad ; a dense fog in less than five minutes after the instrument was placed upon this star, rendered all the stars, Jupiter and Saturn, invisible j the Moon's place also was scarcely to be distinguished. It has frozen all day : the thermometer in the shade stood between 29° and 31°: it now indicates 28°. The instrument is covered with hoar frost, and the fog is so severe that I cannot see across the garden, a distance from the observatory not more than 100 feet. Passy ; February 5, 1825 ; Seven-feet Equatorial. 7th and 15th magnitudes. Position = 6y° 59' nf \ 3 Obs. | Diff. = 0° 59'. Excessively difficult. Observations of distance impracticable ; the small star will not bear the slightest illumination. Passy ; February 9, 1825 ; Seven-feet Equatorial. 7th and 1 5th magnitudes. Position = 68° 22' nf Distance — 2' i".209 c Obs. DifF. = 1° 36' ) Tj . , ,.«. ,^ S Obs. DiflF. = i''.683 i Excessively difficult. Passy; March 21, 1825; Seven-feet Equatorial. 7 th and 15 th magnitudes. Distance — 2' o".09i ± ; single Observation. Excessively difficult. The small star is so excessively faint, that it will not bear even the slightest illu- mination ; and the measure here given was the result of half an hour's attention. Passy ; March 26, 1S25 ; Seven-feet Equatorial. 7th and 15th magnitudes. Distance =: 2' o^'.85i | 5 Obs. | DiiF. = 2".! 15. Excessively difficult. Mean Result. Position 68° 12' nf [9 Obs.) : Epoch 1825.09; Distance 2' 0^.945 (11 Obs.); Epoch 1825.18. Sir W. Herschel has given no measures of this star. (H.) 13^ Mr. South's observations of the apparent distances No. DLXVII. R. A. S^ 15"* ; Decl. 20° 43' N. Nova ; Double ; 7th and 9th magnitudes ; small, blue. Passy ; February 15, 1825 ; Seven-feet Equatorial. Position s= 79° 33' *j> I 5 Obs. Distance = 37".59S 1 5 Obs. Passy ; February 17, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 79° 17' 5 P 1 S Obs. I DifF. = 1° 20' ) r»;fl;^„u Distance = 37".97o | 5 Obs. | DifF. = d'.Z^i ] ^'^^''^^' Passy ; February 24, 1825 ; Portable Transit. Observed R. A. of the larger star = S** 14' 43". u. Mean Result. Position 79° 25' sp ; Distance si'.l^^ ; Epoch 1825.12. No. DLXVIII. R. A. 8^ 17™ ; Decl. 23° 27' S. Nova; Double ; 6th and 9th magnitudes ; small, blue. Passy ; February 21, 1825 ; Seven-feet Equatorial. Position = 4° 32' nf Distance = 4o".464 5 Obs. I DifF. = 10 1 1' 1 sObs. iDifF.^oVzij^^^^^^l^- Passy ; February 23, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. Position =: 5° 8' n/l c Obs. I DifF. = i° 1' > ,. ,._ . Distance = 4i".i6s [ 5 Obs. \ Diff. =0^841 ] ^^^ difficult. Passy ; March 12, 1825 ; Seven-feet Equatorial. Sth and 10th magnitudes. Position = 5° 20' nf c Obs. i DifF. = 1° 3' ) ,. ..a- , Distance = 4o".34» 5 Obs. | DifF. = i".6i i \ ^^^^ ^^^^"1^' Small star is blue, and does not bear a good illumination. Night tolerably clear, but stars of low altitude unsteady. Mean Result. Position 5° o' w/ (15 Obs. ) ; Distance 40". 635 (15 Obs.) ; Epoch 1825.16. and positions of ^^S double and triple stars, &c. 137 • No. DLXIX. R. A. 8^ 23" ; Decl. 25° 25' S. Nova ; Double ; 8th aftd 10th magnitudes : small, blue. Passy ; February 19, 1825 ; Seven-feet Equatorial. Position = 71° 34' «;> I 5 Obs. Diff. = i° 44' ] Excessively difficult. Distance = 39".o33 ( 5 Obs. Diff. = o".649 ) ^ The small star bears but the slightest illumination. Passy ; February 23, 1825 ; Seven-feet Equatorial. 8th and llth magnitudes. Position = 7 1° 33' Y 5 Obs. I Diff. := 1; 2' J Excessively difficult. Distance = 4i".649 ± 2 Obs. | Diff. = o".36o j ^ Observations of distance little else than approximations. Passy ; February 25, 1825 ; Portable Transit. Observed R. A. of the larger star = 8*» 22' 54".88. Passy ; March 18, 1825 ; Seven-feet Equatorial. 8th and llth magnitudes. Distance = 39".S23 1 2 Obs. j Diff. zz o".i68. Excessively difficult. The night iS very fine, but the small star will not allow any illumination of the micrometer wires. Measures entitled to little confidence. Mean Result. Position 71° 34' np (10 Obs.) ; Epoch 1825.13 ; Distance 39".723±(9 Obs.); Epoch 1825.16. MDCCCXXVI. 138 Mr. South' s observations of the apparent distances No. DLXX. R. A. 8^ 29'*; Decl. 2o« 15' N. Nova ; Triple ; A 8|-, B 9^, and C of the 9th magnitudes. Measures of A B.* Passy ; February 19, 1825 ; Seven-feet Equatorial. Position = 6° 3/ nf I 5 Obs. I DifF. = i«» 3' ) difficult Distance = S7".8s 1 | 5 Obs. j DifF. = o".793 ] ^^"^cuit. Passy ; February 23, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position 60 28' „/ I 5 Obs. Diff. = x^ 4' I Very difficult. Distance 57 .055 | 5 Obs. [ Diff. =: ©".962 5 ^ Night hazy ; the small star very faint. Passy ; March 12, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Distance qp 57".6o5 | 5 Obs. ) Diff. = o".6oi. Very difficult. The small star is blue, and bears but a very slight illumination. Measures of A C. Passy ; February 19, 1825 ; Seven-feet Equatorial. 8| and 9th magnitudes. Position = 75° 3' np Distances 2' 57".58i 3 Obs. 3 Obs. Diff. =o« 18' ) Diff. = o".673 5 Passy ; February 28, 1825 ; Seven-feet Equatorial. 8f and 9th magnitudes. 3 Obs. I Diff. = 0° 38' ) 3 Obs. I Diff. = o".625 S ' ' ' Position = 740 25' np Distance = 2' 58".394 Passy ; March 19, 1825 ; Portable Transit. Observed R. A. of the star A = Si^ 29' 5". 18. Declination =20° 15' 16'' N. Mean Result. of AB. Position 6"" 3^' nf (10 Obs.) Epoch 1825.14. Distance 5 7".5 17 (15 Obs.); Epoch 1825.15. of AC. Position 74** 44' w/) (6 Obs.); Distance 2'57".987(60bs.); Epoch 1825.14. and positions of 4^8 double and triple stars y &c. 139 No. DLXXI. R. A. S^ 30"' ; Decl. 20° 8' N. Nova ; Triple ; A 7|-, B 8th, and C of the 6th magnitudes. Measures of A B. Passy ; February 17, 1825 ; Seven-feet Equatorial. Position = 66° 57' sf Distances 44".756 5 Obs. DiflF. = i«» 8' \ 5 Obs. DiflF. = o".48i5 Passy ; February 18, 1825 ; Seven-feet Equatorial. 7 J and 8th magnitudes. Position = 67« $' sf j 5 Obs. | DiflF. = 1° 29' ) Distances 45".3 1 8 | 5 Obs. | DiflF. = o".9i3> " * * Measures of A C. Passy ; February 17, 1825 ; Seven-feet Equatorial. 71 and 6th magnitudes. Position = 29° i' sp | 5 Obs. I Difl". = 0° 36' ) Distance= i' 32".276 I 5 Obs. I Diff. =:o".505 5 * * * C being to the south of A. Passy : February 18, 1825 ; Seven-feet Equatorial. 7th and 6th magnitudes. Position = 29° ^' sp [5 Obs. I Diff. o« 17' ) Distance = i' 32". 238 | 5 Obs. | Diff. i".443 > * ' * The star C being to the south of A. Passy ; March 18, 1825 ; Portable Transit. Observed R. A. of the star A = S** 29' 56".3i. Declination 20° 8' o" N. Mean Result. of A B Position 67° 1' sf; Distance 45".037 ; of A C Position 29° 2' sp ; Distance 1' 32".257; Epoch 1825.13. 140 Mr. South's observations of the apparent distances . No. DLXXII. R. A. S^ 30"^ ; Decl. 20° 16' N. Nova ; Double ; 7th and 9th magnitudes ; small, blue. Passy ; February 19, 1825 ; Seven-feet Equatorial. Position =: o" 16' n/ 15 Obs. Diff. = 0° 33' ) Distance = 1' I5".8ii | 5 Obs. DifF. = i".o58J • • • • Passy ; February 23, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position s= 0° 17' nf Distance = i* i6".o%2 5 Obs. 5 Obs. DiiF. =3 0°32'|p..fl.^,,^ DifF. = i".8o3j^^®'^^^^- Passy ; March 21, 1825 ; Portable Transit. Observed R. A. of the larger star = S"* 30' 2o".43. Declination = 20" 16' 7' N. Mean Result. Position o"* iGf nf; Distance i' i5"-94f6 ; Epoch 1825.14. . No. DLXXIII. R. A. 8^ 30"* ; Decl. 20° 15' N. Nova ; Double ; 6th and 12th or 15th magnitudes ; the small star is a mere point, yet bears a very tolerable illumination. The large star forms a triangle with the double star No. 572, itself being at the vertex of the triangle. Passy ; February 19, 1825 ; Seven-feet Equatorial. Position = 37° 6' nf Distance = 20*.288 Sb:: I Ell :;°.f?4}E««-'y ■•"«-"• Passy ; February 25, 1825 ; Seven-feet Equatorial. 7th and 15th magnitudes. Position = 36° 58' nf Distance = 21 ".096 5 Obs. Diff. = 1° 40' ) Excessively difficult. S Obs. DifF. = i".683 ) ^^cessivexy airacuit. and positions of4>5S double and triple stars ^ ^c. 14I No. DLXXIII. continued. Passy ; March 19, 1825 ; Portable Transit. Observed R. A. of the larger star, Z^ ^o'z\''.^2. Declination = 20° 15' 5'' N. Passy; March 21, 1825 ; Seven-feet Equatorial. 1 have tried several times, on different fine nights, to procure other measures of this double star ; but although the weather has been particularly favourable, I have not been able to succeed. Is the small star variable ? Passy ; April 6, 1825 ; Seven-feet Equatorial. I have been again foiled in my endeavours to measure this double star ; yet the night is beautifully clear. I can distinguish the small star, but under the least illumination it is invisible. Mean Result. Position 37° 2' nf ; Distance 20^692 ; Epoch 1825.14. No. DLXXIV. R. A. 8^ 30" ; Decl. 20*' 8' N. Nova ; Double ; 6th and 7th magnitudes ; its larger star follows the star A of the triple star No. 571, about 31 seconds of time, and is about 23 seconds to the south of it. Passy ; February 17, 1825 ; Seven-feet Equatorial. Position = 200 59'*^ I 5 Obs. I Diff. = 0° 29' \ Distance = 2' 12" .449 | 5 Obs. | Diff. = o".962 1 • • • • Passy ; February 18, 1825 ; Seven-feet Equatorial. 7th and 8th magnitudes. Position = 2i» $' sp I 5 Obs. Diff. = 0° 18' \ Distance = 2' 1 3". 151 I 5 Obs. Diff. = i".755> • • • • Passy ; March 10, 1825 ; Portable Transit. Observed R. A. of the larger star = S** 30' 27".22. Declination = 20° 7' 37" N. Mean Result, Position 21° 2' sp ; Distance 2' 12".803 ; Epoch 1825.13. 142 Mr. South's observations of the apparent distances No. DLXXV. R. A. 8^ 31" ; Decl. 6<» 25' N. Struve, 303 ; IV. 54. Double ; 8th and 10th magnitudes. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position = CQ° 52' n/ 5 Obs. I DifF. = i® 25' i r»;fl;^„u Distance = zf.yi 1 5 Obs. \ DifF. = o".937 j difficult. Passy ; January 25, 1825 ; Seven -feet Equatorial. 8th and 10th magnitudes. Position = 59" 43' nf Distance = 27".396 c Obs. I Diff. = 1° 40' I y^.n, ,^ 5 0bs.|DifF. = o".6oiJ^^*^"^^' Passy ; April 7, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Distance = 2/' .042 | 5 Obs. | DifF. = o".yzi. Difficult. Mean Result. Position 59° 47' nf (10 Obs.); Epoch 1825.03 ; Distance 27". 383 (15 Obs.) ; Epoch 1825.11. This star has undergone no appreciable change, as the measures of 1783 gave Position 59° ^^h* nf (mean of tw^a measures) ; Distance 25". 7. (H.) No. DLXXVI. R. A. 8^^ 31" ; Decl. 49° 30' N. Struve, 304; P. VIII. 131 ; Double ; 9^ and 10th magnitudes. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position :=6i° io'«j» I 5 Obs. Distances io".995 | 5 Obs. DifF. = 0° 54' ) T^.n: 1^ DifF. = o".288l^^^^"^^' Passy ; January 25, 1825 ; Seven-feet Equatorial. 9th and 9^ magnitudes. Position = 60° 47' np I c Obs. I Diff. = 3** 47' Kr _ .-«: 1. Distance = 9".67i | 5 Obs. | Diff. = o".7i5 J ^^^ ^'^^^^'' Passy ; February 3, 1825 ; Seven-feet Equatorial. 9| and 10th magnitudes. Distance = io".289 | 6 Obs. | Diff. = i".034. Very difficult. Mean Result. Position 60° 58' np (lo Obs.); Distance io".3i6 (16 Obs.); Epoch 1825.05. and positions of 4f5S double and triple stars, &c. 143 No. DLXXVII. R. A. S'* 33" ; Decl. ii'' 33' S. Struve, 305 ; Hist. Gael. 270 ; Double ; 9th and 10th magnitudes : both bluish. Passy ; January 2, 1 825 ; Seven-feet Equatorial. Position rz 30° 55' np \ 7 Obs. Distance =: 5".475 j 5 Obs. Kff:=!.°.|l'.!E«'™''y<"ffi«"- 721 ) Passy ; January 25, 1825 ; Seven-feet Equatorial. 9f and 10th magnitudes. Position =3iO 24' „;, 7 0bs.|Diff. = s°S' I Excessively difficult. Distance r= 5 .703 5 Obs. j Dift. = o".769 5 ' Mean Result. Position 31° 9' np (14 Obs.) ; Distance 5".5S9 (10 Obs.); Epoch 1825.03. No. DLXXVIII. R. A. 8^ 33" ; Decl. 11° le' S. Nova ; Double; 8th and 11th, or 12th magnitudes. Passy ; February 21, 1825 ; Seven-feet Equatorial. Position r= 32° 4-'np\s Obs. Diff. = 1° 42' ) E„tremelv difficult Distance = 3o".970 | 5 Obs. DifF. = i".202 § Extremely ditticuit. Observations of distance perhaps a little doubtful. Passy ; February 24, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position = 32;; 13' np I 5 Obs. 1 Diff. = o° 30' ) Extremely difficult. Distances 30 .646 j 5 Obs. | Diff. = r .8275 ' The small star is blue, and bears only the most feeble illumination. Mean Result. Position 32° 6' np; Distance 3o".8o8 ; Epoch 1825.14. 144 Mr. South's observations of the apparent distances No. DLXXIX. R. A. 8^ sa"^ ; Ded. 6° ss' S. SI Monocerotis ; South's Catalogue ; VI. 82. Double ; 6th and 9th magnitudes ; small, blue. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position =38° 36' np ; 5 Obs. I DifF. = 0° 56' ) Distances 1' 1 7".52o | 5 Obs. | DifF. = o".48i > • • • • Passy; January 17, 1825 ; Seven-feet Equatorial. 6th and 9tli magnitudes. Position = 38° 34' np I 5 Obs. 1 DifF. = 1° 6' ) Distancer: i'i8".3i6 I 5 Obs. I DifF. =o".6975 • • • • Mean Result. Position 38° 35' np; Distance i' I7".9i8 ; Epoch 1824.02. The angle of position of this star as measured in 1783 was 40° o' np, differing only 1° 25' from the present. (H.) No. DLXXX. R. A. 8^ 36"^ ; Decl. 1° 57' S. Struve, 308 ; P. VIII. 160. Double ; 81- and 9th magnitudes ; small, blue. Passy; January 2, 1825 ; Seven-feet Equatorial. Position = 12° 2' sp Distance = 4".374 5 Obs. I DifF. = 0° 52' 5 Obs. I DifF. = o".9i3 Passy; January 17, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 11° 6' sp\ s Obs. I DifF. = i° 49' ) Distance = 5".487 | 5 Obs. | DifF. = o".3365 ' ' * Passy ; February 3, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Distance = 4".99i ( 5 Obs. I DifF. = o".673. ... Mean Result. Position 11° 34' sp (lo Obs.) ; Epoch 1824.02 ; Distance 4".95i (i5 Obs.) ; Epoch 1825,04. and positions 0/4,58 double and triple stars, &c, 145 No. DLXXXI. R. A. 8^^ s?"' ; Decl. 11° 50' N. Struve, 30.9; Hist. C^el. 218. Double ; 9th and 9^ magnitudes. Passy ; January 29, 1825 ; Seven-feet Equatorial, Position = 82° 24' np 6 Obs. DifF. = 3° 5' > -,. ..«: t^ Distance= i3".758 5 Obs. DiiF. = o".986 J ^^^ ^^^^^<^- Night extremely favourable ; but neither star bears sufficient illumination. Passy; February 3, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 84° 11' »o I 5 Obs. I DifF. = 1° i' 7 ,. ..g- ^^ Distance = iJ'.p+j "^ | 5 Obg. | Diff. = o".84i } ^^^ ^^'="^*- Passy ; February 11, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 84° o' «;> I 5 Obs. I DifF. = 1° 1' ) ,^ ,.n- , — Distance = I3".279 | 6 Obs. | Diff. = o".6oi ] ^^^ difficult. Thermometer stands at 28° ; no dew on the object-glass j but on the polar axis there has been a considerable quantity, throughout the night. Mean Result. Position 83° 27' np (16 Obs.) ; Distance 13''.324 (16 Obs.) ; Epoch 1825.09. No. DLXXXII. R. A. 8»> S9' ; Decl. s6° 45' N. 130 (Bode) Lyncis ; Struve, 310; Hist. Gael. 220. A very neat double star ; nearly equal ; 9th and 9^ magni- tudes, and bear a very good illumination. Blackman-street ; March 12, 1824 ; Five-feet Equatorial. Position =: 7° 30' sf Distance = 3''.556 5 Obs. 5 Obs. Diff. = 1° o' ) Diff. =: o".632 ] Blackman-street; March 31, 1824 ; Five-feet Equatorial. Equal ; each 9th magnitude. ^ Position z= 7° 43' sfornp j 5 Obs. Distance = 3". 767 j 5 Obs. Diff. = 1° 58' ) Diff. =:o".5295 Mean Result. Position 7° 36' sfornp ; Distance 3". 661 ; Epoch 1824.22. MDCCCXXVI. u I4f6 Mr, South's observations of the apparent distances No. DLXXXIII. R. A. 8^ 41" ; Decl. ss' 9' N. ' sp \ 5 Obs. I Diff. = 0° 37' \ Very difficult. Distance = i'^ii".356 j 5 Obs. | Diff. =o".9i3 ) ^ Mean Result. Position 58^ 49' sp ; Distance 1' ii".i89 ; Epoch 1825.22. and positions 0/4.58 double and triple stars, &c. 14«7 No. DLXXXV. R. A. 8^ 47" ; Decl. 17° 34' S. Nova ; Double ; 6th and 7th magnitudes. Passy ; March 19, 1825 ; Seven-feet Equatorial. Distance = i'g"'.2gS \ 5 Obs. | Diff. Passy; March 21, 1825; Seven-feet Equatorial. Position = 53° 9' «/I 5 Obs. I DiflF. = 0° 56' 7 ■ ' ~"T. = o".84ij • • 6th and 7th magnitudes. Position =53° 20' sf 5 Obs. I DiflF. = o" 56' F. = 0° 56' I Distance = V 9".S94 5 Obs. | DiflF. =o".432 3 • • • • Passy ; March 21, 1825 ; Portable Transit. Observed R. A. of the larger star = 8^ 47' iz".S9. Passy ; March 24, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position = 53° 8'*/ 5 Obs. I DiflF.= 1° 16' ) Unsteadv Distance= 1' 9".i97 5 Obs. | Difi^.= i".6595 "^^steady. Measured inadvertently, being unaware that the star had been already well observed. Mean Result. Position 53° is' np (15 Obs.); Distance 1' 9". 36s (15 Obs.); Epoch 1835.22. No. DLXXXVI. R. A. S^^ 50" ; Decl. 32° 57' N. ; Distance i2".i40; Epoch 1824.22. No. DXC. R. A. 8^ 58'" ; Decl. 53** 6' N. ,^^ Struve, 325 f Double ; 9th and 1 ith magnitudes ; small, blue. Passy ; February 6, 1825 ; Seven-feet Equatorial. Passy ; February 9, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position Distance Position = 57« i6' sf\ 5 Obs. Distance = $"'3^4- I 5 O^s. Sif = ^^3' } Very difficult. Diff. = o .529 5 ' Night very favourable. M?a;z Result. Position 56° 31/ ^/(ii Obs.); Distance 5". 513 (10 Obs); Epoch 1825.10. 150 Mr. South's observations oj the apparent distances No. DXCI. R. A. 9^ o^ ; Decl. 16^ o' N. Nova; Double ; 9th and 12th magnitudes. Passy ; February 19, 1825 ; Seven-feet Equatorial, Position = 29° 51' «/f 7 Obs. I DifF. = 4° 8' 1 n ^ ^ a-x 1. Distance =7^598 5 Obs. | DifF. = 3". 5 77 } Extremely difficult. Passy ; February 24, 1825 ; Seven-feet Equatorial. 9th and 12th magnitudes. Mean Result. Position 29° se' nf {i4> Obs.) ; Distance 7".634(io Obs.) ; Epoch 1825.14. No. DXCII. R. A. 9*^ 1" ; Decl. 53** 28' N. Struve, sa8 ; Double ; equal ; each of the 8th magnitude. Blackman-street ; March 31, 1824 ; Five-feet Equatorial. Position = 44° 18' sp orn/ j 5 Obs. | DifF. = 1° 31' . . . . Blackman-street ; April 3, 1824 ; Five-feet Equatorial. 71 and 8th magnitudes. Position =: 44° 9' nf I 5 Obs. Distance zz 2o,"667 | 5 Obs. DifF. = 1° 2Q' ) DifF. =:o".947 5 Passy ; February 6, 1825 ; Seven-feet Equatorial. Equal; each of the 8th magnitude. Distance = 2o".925 | 5 Obs. | DifF. = i".202 . . . Night tolerably good ; a small quantity of dew has fallen upon the object-glass, but the polar axis, which during the former part of the night has been very wet, is, now coated with ice. Thermometer 28°. Mean Result. Position 44°i3'w/; Epoch 1824.25 ; Distance 20". 796; Epoch 1824.67. and positions 0/4*58 double and triple stars, &c. 1.51 No. DXCIII. R. A. 9^ 4" ; Decl. 79" 15' N. Nova; Double ; 8^ and 9th magnitudes ; bear a very good illumi- nation ; their juxta-polar situation, and their position (so near the perpendicular), render them admirably adapted for parallax observations. Passy ; March 18, 1825 ; Seven-feet Equatorial. Position = 81° 14' sf I 5 Obs. [ DiiF. = o° 32' 7 Distance = 29".384 j 5 Obs. J DiflF. = o".i44 5 Passy ; March 21, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 81® 14' 5/ 1 5 Obs. Diff. = 1° 24' ) Distances 29''.256 | 5 Obs. DifF. = o".48i ) Mean Result. Position 8i' 14' sf; Distance 29".32o ; Epoch 1825.21. No. DXCIV. R. A. 9^ 7"" ; Decl. 24" 24' N. Struve, 332 ; Hist. Csel. 215 ; Double ; 9t and 10th magnitudes. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position =: 73° 38' nf Distance — 7". 302 8 Obs. I Diff. = 1° 55' ) „ ..-. . 5 Obs. I Diff. = o".48i } V*^ ^^^<^"^*- Passy ; February 3, 1825 ; Seven-feet Equatorial. 9| and 10th magnitudes. Position = 73° 4' w/ 1 5 Obs. I Diff. = 1° 35'. Very difficult. Night is become cloudy ; no more observations can be made. Passy ; February 5, 1825 ; Seven-feet Equatorial. 9| and 1 0th magnitudes. Distance = d^pii | 5 Obs. | Diff. = o'^s^. Very difficult. Mean Result. Position 73° 25' nf{i3 Obs. ; Epoch 1825.04 ; Distance i'.ioi (10 Obs.); Epoch 1825.06. 152 Mr. South* s observations of the apparent distances No. DXCV. R. A. 9^^ lo' ; Decl. 19° 35' S. Nova ; Double ; 8^ and 10th magnitudes. Passy; February 19, 1825 ; Seven-feet Equatorial. Position = io« 7' no I 5 Obs. I Diff.= 1° 27' ) ,r ..«. ,^ Distance = 1' i".i69 | 5 Obs. | DifF. = o".937 ] ^^^ difficult. The small star bears but very little illumination. Passy ; February 24, 1825 ; Seven-feet Equatorial. 8th and 1 1th magnitudes. Position = 9° 57' np \ c Obs. DifF. =p° 32' 7 „ ^ , ..-, , Distance = i' i".i26 | 5 Obs. Diff. = i".49i j Extremely difficult. Passy; March 21, 1825 ; Portable Transit. Observed R. A. of the larger star = 9'' 10' 2^".gS. Mean Result. Position id* ^' np\ Distance i' i".i47; Epoch 1825.14. No. DXCVI. R. A. 9M0' ; Decl. 50° 18' N. 39 Lyncis ; Struve, ssS- Double ; 8th and 10th magnitudes ; small, blue. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position = 50° 1' np 5 Obs. Distance = $"-7^9 5 Obs. Position =: 49° 33' np 5 Obs. Position = 49° 2' np 5 Obs. DifF. = 4° 22' ■) DifF. = o".86s K, ,.^ , DifF. = 3° 30' r^'^y difficult. DifF. = 2° AC' ) Passy; January 17, 1825 ; Seven-feet Equatorial. 8th and 10th or 11th magnitudes. Position =47°48'«o 6 Obs. I DifF. = 6° 1 2' | ^j ^ , ,.^ , Distance = 6^'.400 5 Obs. | DifF. = o".72i ] Extremely difficult. Passy; February 24, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 50° 34' np 15 Obs. DifF. = 2^44' ) Oatisfartnrv Distance = 6".049 5 Obs. DifF. = o".6o i ] Satisfactory. Stars admirably defined, and are remarkably steady ; the small one is blue. The observations were gotten with the greatest facility. Mean Result. Position 49° 40' np (36 Obs.) ; Distance 6^.059 (15 Obs.) ; Epoch 1825.06. and positions of 458 double and triple stars y ^c 153 No. DXCVII. R. A. 9"" 14" ; Decl. 4' 17' N. Struve, 338 ; Hist. Gael. 324 ; Double ; 8th and 9th magnitudes ; small, blue. Passy ; January % 1825 ; Seven-feet Equatorial. Position = 40° 31' n;) 1 5 Obs. Diff. = 2° 34' 7 Distances 22". 1 95 j 5 Obs. DifF. = o".3i2 j • • • • Passy ; January 6, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 40° 20' np \ 5 Obs. 1 Diff. 2° 15' ) Distance = 22". 143 | 5 Obs. | Diff. o'.4o8 3 • • • • Mean Result. Position 40° 25' np ; Distance 22". 169 ; Epoch 1825.01. • No. DXCVIII. R. A. 9'' 17' ; Decl. 46** 26' N. Struve, ss9 ; IV. ss ; Double ; 6th and 8 i- magnitudes ; small, blue. Blackman-street; April 12, 1824; Five-feet Equatorial. Position = 71° 18' «/ I 5 Obs. I Diff. o° 12' \ n^^^^„ -^ Distance = i' z&'.jgj 1 5 Obs. j Diff. 0^.727 ) ^^^^^' i Position = 71° 17' «/ 5 Obs. I Diff. 0° 53' ) ^^^ xi.r,^.-or.or.^r i ' ' Distance = 1' 27 .075 5 Obs. j Ditt. o' .821 ) J Passy ; January 6, 1825 ; Seven-feet Equatorial. 7th and 9th magnitudes. Position = 71^ 59' */ Distance = i'26".ii9 5 Obs. 5 Obs. Diff. = 0O56' ^ Diff. = o".3845 Passy ; February 20, 1825 ; Seven-feet Equatorial. 6th and 9th magnitudes. Distance = 1' 26".6o5 | 5 Obs. 1 Diff. o".673 . . , . Mean Result. Position 71° 31' ^/ ( 15 Obs. ); Epoch 1824.64 ; Distance i' 26".649 (20 Obs.); Epoch 1824.81. MDCCCXXVI. X L54 Mr. South' s observations of the apparent distances No. DXCIX. R. A. 9"" IS"* ; Decl. 7" 1' N. Struve, 341 ; Hist. Gael. 273. Double ; equal ; each of the 10th magnitude. Passy ; January 17, 1825 ; Seven-feet Equatorial. Distance = j,".yZo \ 5 Obs. | Diff. r: o" .^yj. Excessively difficult. Passy ; February 5, 1825 ; Seven-feet Equatorial. 9 J and 10th magnitudes. Position = 58' 55^ «i> I 5 Obs. Distance = 3". 450 j 5 Obs. Diff: « o''.697} Extremely difficult. Passy ; March 2, 1285 ; Seven-feet Equatorial. 9 th and 9^ magnitudes. Position = 56° 29' nf I 5 Obs. I Diff. = 2° 42' ) ^ ^^ Distance = 3 .251 | 5 Obs. | Diff. = o".336) ^ Passjr ; March 26, 1825 ; Seven-feet Equatorial. Equal; each of the 10th magnitude. Position r: 57° 38' «p or «/ Distance =: 3".S72 Diff! = o''.6o, I Extremely difficult. 5 Obs. 5 Obs. Mean Result. Position 57° 41' np or 5/(15 Obs.); Distance 3*.5i3 (20 Obs.); Epoch 1825.13. No. DC. R. A. 9^ 19"" ; Decl. 9° 5o' N. «^ Leonis ; Struve, 342 ; I. 26. Double ; large, white ; small, pale blue. Royal Observatory, Paris; March 15, 1825 ; Eleven-feet Achro- matic by Lerebours, having an object-glass of 8.4 English inches clear aperture. With a power of 420 the small star is separated half a diameter of the large star ; with 560 three-fourths of a diameter ; with each power the stars are admirably de- fined, and as round as possible : had we any micrometrical apparatus, measures of position and distance might be gotten with the greatest facility. Mons. Bouvard present. Night favourable. Whether the Seven-feet Equatorial will enable me to measure this close double star I do not know ; the highest power that can be applied to its present micrometer is 273, which is certainly inadequate to show the star double* • By a letter from Mr. Herschel, dated May 14, 1825, 1 find that Mr. Struve has measured this star with his telescope of 9 inches aperture, and 14 feet focal length, made by Fraukhofer. and positions of ^^S double and triple stars, (^c. 155 No. DCI. R. A. 9^ ai"" ; Decl. 73" 52' N. • ^ ^ Struve, 345 ; Double ; equal ; each of the 8th magnitude. Blackman-street ; April 12, 1824 ; Five-feet Equatorial. Position = 44** 37' np or sf \s Obs. I Diff. = 2° / ^ ^ Distance = s".i44 | 5 Obs. | Diff. = o".y27 > ^°^^^' Position = 42*^ 56' np or */ 5 Obs. Diff. = i" 8' ) ^ Richardson Distance = 4".822 | 5 Obs. | Diff. = i".i 36 j ^^' ^ichardsok. Passy; February 20, 1825; Seven-feet Equatorial. 9th and 9J magnitudes. I Position = 45° 35' sf Distance =: s".oo3 5 Obs. Diff. = 1° 25' ) 5 Obs. Diff. = 0 ".456 j • Passy ; March 18, 1825 ; Seven-feet Equatorial. 8th and 8^ magnitudes. Position = 45° 38' sf\ 5 Obs. Distance = S".393 | 5 Obs. Diff. = 2° ic Diff. ". = 2° ic' ) ■. = o".4565 • • • Mean Result. Position 44° 41' sf (20 Obs.) ; Distance 5".o9o (20 Obs.); Epoch 1824.87. No. DCII. R. A. 9"" 23"° ; Decl. 2° le' N. Struve, 347 ; Double ; 9th and 9^ magnitudes, and bear a very tolerable illumination ; the small star is blue. Passy ; February 9, 1825 ; Seven-feet Equatorial. Position = 74<» 51' */| 5 Obs. I Diff. = 1° 46' ) Distance = 3". 5 84 | 5 Obs. ) Diff. = 0". 505) * * ' Night remarkably fine. Passy ; February 17, 1825 ; Seven-feet Equatorial. 9th and 9^ magnitudes. Position = 73«> 41' */ 5 Obs. ! Diff. = 3° 9' ) Distance = 3".948 5 Obs. j Diff. = o".s53 ) * * ' Mean Result. Position 74° 16' sf; Distance 3".766; Epoch 1825.11. 166 Mr. South' s observations of the apparent distances No. DCIII. R. A. 9^ 24™ : Decl. 40° 46^ N. Struve, 349 ; Hist. Gael. 215; Triple ; A 7th, B 8|-, and C of the 9th magnitudes. Measures of A B. Blackman-street ; March 31, 1824 ; Five- feet Equatorial. Position = 56° 43' */ 1 5 Obs. Diff. = i° 32' Distance r: 2^'. 6^6 \ 5 Obs DifF. = 1° 32' \ = i".oio5 • • • • Blackman-street ; April 2, 1824 ; Five-feet Equatorial. 7th and 8^ magnitudes. Position = 58'> 5' */l 5 Obs. I Diff. = 1° 42' ) Distance = 24". 5 07 | 5 Obs. | Diff. =:o".6oo5 • • • • The small star is decidedly blue. Passy ; Februaiy 20, 1825 ; Seven-feet Equatoiial. 7th and 8| magnitudes. Position = 56° 33' sf \ 5 Obs. | Diff. = 0° 38'. Measures of A C. Blackman-street ; March 31, 1824 ; Five-feet Equatorial. 7th and 9th magnitudes. Position = 55° 40' np \ 3 Obs. Diff. = 0° 10' \ rvj^.^i. Distance = i' 58".364 | 3 Obs. Diff. = i".832 5 ^^^uit. The star C is very indistinct. Blackman-street ; April 2, 1824 ; Five-feet Equatorial. 7th and 9th magnitudes. Position = 55° 10' nj9 J 3 Obs. I Diff. = 0° 5' ) Distance=:i'58".853 I 3 Obs. I Diff.= i".oio5 • • • • Mean Result. of A B. Position 57° 7' sf{i5 Obs.) ; Epoch 1824.54 ; Distance 24".58i (10 Obs.) ; Epoch 1824.25. of AC. Position S5° 25' np {6 Obs.) ; Distance 1' 58".6o8 (6 Obs.); Epoch 1824.25. and positions qf4fS8 double and triple stars, &c, 157 No. DCIV. R. A. 9^* s?"" ; Decl. 18° 48' S. Nova; Double ; 7th and 11th magnitudes. Passy ; February 21, 1825 ; Seven-feet Equatorial. Position = 1° o' */ 1 5 Obs. I Diff. = o° co' 7„ • , j.^. ,^ Distance = si".75^ | 5 Obs. | DifF. = I'.jzz JE^cessively difficult. The small star is extremely obscure, and the measures of distance are perhaps a little questionable. Passy ; February 21, 1825 ; Portable Transit. Observed R. A. of the larger star =: 9*" 27' 28".28. Passy ; March 24, 1825 ; Seven-feet Equatorial. 7th and 1 Ith magnitudes. Position 0° o' ; following | c Obs. I DiiF. = 1° ^' 7 ,, . , ,.«- ,^ Distance = s^"'9^\ I 5 Obs. | Diff. = i".oio \ Excessively difficult. Before the mean angle was known, the position wire was placed at Zero, and the large star being bisected by it, I could not satisfy myself whether to assign the small one to the north or south quadrants. The measures, particularly of distance, may be liable to a slight inaccuracy, for the small star will scarcely bear any illu- mination. Night fine. Mean Result. Position 0° 30' 5/; Distance 51^.840 ; Epoch 1825.17. No. DCV. R. A. 9^ 45°* ; Decl. 5° 48' N. 9 Sextantis ; Struve, s5^ ; Hist. Ccel. 327. Double ; 7th and 9th magnitudes ; small, blue. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position = 220 38' np I 5 Obs. I Diff. = o" 18' 7 <, , Distance = 51 ".034 | 5 Obs. 1 Diff. = o".6\^ j otcaay. Passy ; January 6, 1825 ; Seven-feet Equatorial. 7th and 9th magnitudes. Position =22° 48' np 5 Obs. Diff. = 1° 33' | Good observations. Distance = 51 '.010 5 Obs. Diff. = 1'. 058 j The past has been a night such as rarely, very rarely occurs ; from five o'clock in the afternoon till now, (four o'clock in the morning,) the stars have been unusually tranquil, and most exquisitely defined. At the commencement of the observations the Thermometer in the observatory stood at 31°, and it has gradually fallen to 23°. The deposition of moisture on the interior surface of the object-glass, and its 158 Mr. South's observations of the apparent distances No. DCV. continued. crystallisation on the exterior surface, have been so considerable, although an attached deal tube projects twelve inches beyond it, that I have been obliged to remove it very frequently ; but no trouble is too great to obtain measures, under circumstances so peculiarly favourable. Tvi^enty stars have been observed, amongst them several of the most difficult, and some which I have never before seen double. Now however the dew is not confined to the parts of the telescope in the neigh- bourhood of the object-glass, but has attacked the wires of the micrometer; they have a serrated appearance ; and I suspect begin to ** fiddle." Prudence advises me to relinquish observing, lest by persevering they should become broken. Many nights since my abode here, the dew has been far more copious, than I ever ob- served it to be in England ; frequently the water has dripped off the instrument for several successive hours, but I never had any reason to suspect the slightest preci- pitation of moisture on the micrometer wires. The polar axis and object-end of the telescope, which in the earlier parts of the night were covered with hoar frost, are now coated with ice. ..^i^^^^a Mean Result. Position 22<» 43' np (10 Obs.); Distance 5i".o22 (10 Obs.); Epoch 1825.01. No. D CVI. R. A. 9^ 47'" ; Decl. 200 si N. Struve, S5S ; Hist. Cash 212. Double ; 8th and loth magnitudes ; small, blue. Passy ; January 2, 1825 ; Seven-feet Equatorial. Position = 85° 17' sf 5 Obs. I DifF. = 1° 8' ^ t^.^ , Distance = zi^'.jzs 5 Obs. | DifF. = o".3i2 5 ^'^c"^*' Passy ; February 5, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 84° 6' sf S Obs. i DifF. = )ifF. = 1° 19' ) T,.- . Distance = 3o".4i j 5 Obs. j DifF. = d'.s^g ] ^^*C"^*' Night very fine. Snow on the ground five or six inches deep. Thermometer in the observatory stands at 27°. $. No dew on the object-glass.* Mean Result. Position 84° 41' sf; Distance so".07i ; Epoch 1825.04. * To obviate the annoyance occasioned by the dew, wadding, such as is here employed in the manufacture of Ladies' pelisses, was on February ist placed fo a thickness of three-quarters of an inch, around the tube to which the micrometer is attached, to that of wood applied to the object-end, and to all the telescope tube projecting beyond the declination circle of the instrument : it has to a very consi- derable extent answered the purpose. Passy, October 22, 1825. and positions of ^SS double and triple stars, &c. 159 No. DCVII. R. A. 9^ 58" ; Decl. iS"* 26^ S. Struve, 356 ; Hist. Csel. 283. Double ; equal ; each 9^ or 10th magnitudes ; bluish, and scarcely bear any illumination. Passy ; February 9, 1825 ; Seven-feet Equatorial. Position = 55° 48' np or sf 5 Obs. 1 Diff. = 2° 31' 7 Extremely difficult. Distance = 1 1".447 5 O^s. \ Diff. = o .553 j ^ Passy ; February 24, 1825 ; Seven-feet Equatorial. Equal ; each of the 10th magnitude. Position zz 56° 36' 71 p or sf\s Obs. | Diff. = 1° 59' I Extremely difficult. Distance = i i".2S7 \ 5 Obs. \ Diff. = o".g6z ) Mean Result. Position 56° W np or sf; Distance ii".352 ; Epoch 1825.12. No. DCVIII. R. A. 10^ 16- ; Decl. 9° 39' N. Struve, 363 ; I. 29. Double ; 9th and 10th magnitudes ; small, blue. Passy ; February 9, 1825 ; Seven-feet Equatorial. Position = 23° 58' »/ 6 Obs. Diff. = 3° S°' X Very, or extremely Distance = 2". 760 6 Obs. Diff. = o".889) difficult. These stars are admirably defined, and are as steady as possible. Observed when on the meridian. The night is particularly favourable for delicate observations. Passy ; March 24, 1825 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position = 27° 45' «/| 8 Obs. 1 Diff. = 6° 28' ) Excessively difficult. T»;c<-on/«. — c" TiA c Obs- Diff. = o .At2 { ' Distance = 5".734 I 5 Obs. | Diff. = o".432 j The small star is blue, and scarcely bears any illumination. Passy ; March 28, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 25° 13' n/ 5 Obs. Diff. = 2° 34' | Excessively difficult. Distances 3 .981 5 Obs. Diff. = ©".48 1 > ' Night very fine ; but the small star, which is blue, bears only the most feeble illumination. i6o Mr. South's observations of the apparent distances No. DCVIII. continued. Passy ; March 29, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 24° 28' nf 5 Obs. I DifF. = 4^45' ^ Excessively difficult. Distance = 4'.2SS 5 Obs. | DifF. = o''.745 ) ^^^^^^^^^^^ aimcuit. These observations, particularly of distance, do not accord so well as might be wished ; the star however is one which presents considerable difficulty : this circumstance must plead their excuse. By allowing all the measures equal weight, I apprehend we shall not err much from the truth, when we give as the Mean Result. Position 26° 1' nf{24f Obs.) ; Distance 3".632 (21 Obs.); Epoch 1825.20. This star offers not the least evidence of change either in position or distance. The angle of 1782 differs only 31' from that here assigned ; and the distance (2 diameters) for stars of this magnitude may (from centre to centre) amount to about 4". (H.) No. DCIX. R. A. 10^ 22"^ ; Decl. 22° 58' N. Struve, 364 ; Hist. Gael. 150. Double ; 9th and 9j magnitudes, and bear a very tolerable illumination. Passy ; February 9, 1825 ; Seven-feet Equatorial. Position = 65" 50' sf \ 5 Obs. I DifF. = 0° 48' \ Distance = I4".s88 j 5 Obs. | DifF. = i".274> * * * ' Passy; February 28, 1825; Seven-feet Equatorial. 9th and 9J magnitudes. Position = 65° 51' */ Distance = 14" .090 5 Obs. DifF. = 0° 24' 7 5 Obs. DifF. = o".649 3 ' ' Passy ; March 10, 1825 ; Seven-feet Equatorial. 9th and 9^ magnitudes. DifF.= DifF. '. = 0° 38' > . = o".649} Position = 64° 50' sf 1 5 Obs. Distances i3".938 j 5 Obs. Mean Result. Position 65° 30' 5/(15 Obs.) ; Distance i4".205 (i5 Obs.) ; Epoch 1825.09. and positions 0/458 double and triple stars ^ &c. 161 No. DCX. R. A. io»^ 26°^ ; Decl. 16° 54! S. Nova ; Double; 10th and loj magnitudes. Passy ; February 23, 1825 ; Seven-feet Equatorial. Position = 54° 4; «/ 5 Obs. I Biff. = 109' ) ^^^^^^^^^^^ difficult. Distance = i'4o".6i8± i Obs. | — — — 5 ' The distance is probably little better than a guess. Passy ; March 24, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. An illumination sufficient to render the micrometer wires distinct, obliterates both the stars. Position = 54" 9' nf Distance = i'4o".9i5 Mean Result. Position 54° 6' nf {10 Obs.) ; Distance 1' 40". 865 (6 Obs); Epoch 1825.18. No. DCXI. R. A. io»> 33™ ; Decl. 13° 49' S. Nova ; Double ; 10th and 11th magnitudes. Passy ; February 24, 1825 ; Seven-feet Equatorial. Position = 76° ci'sp \ 5 Obs. DifF. = 0° 45' 7 ^ ^ . , ,.-e 1^ Distance = s^".U7± I 5 Obs. Diff. = i-.Tso \ Ex^^^^^^X ^^^^"1*- Measures of distance somewhat of a suspicious character. The stars will scarcely bear any illumination. Passy ; March 24, 1825 ; Seven-feet Equatorial. 11th and 12th magnitudes. Position =: 75° 40' sp 1 5 Obs. I DifF. = 0° 55' ) „ ^- • 1 j-m 1^ Distance = 59".695 ^ | 5 Obs. | DifF. = ,".154 \ Excessively difficult. When the field of view is but very slightly illuminated, the stars cannot be seen without the greatest attention. Mean Result. Position iG^ 15" sp\ Distance 59".S3i ; Epoch 1825.18. MDCccxxvi. y 162 Mr. South' s observations of the apparent distances No. DCXII. R. A. 10^36°'; Decl. 31° si N. 42 Leonis minoris; Struve, 366 ; Hist. Gael. 506; Double ; 6th and 8th magnitudes. Passy ; March 12, 1825 ; Seven-feet Equatorial. Position = 82° 35' sf I 5 Obs. DifF. = 0° 14' \ Distance = 3' 2o".o62 | 5 Obs. DifF. = o".649 ^ • • • • Observed when i\ hour east of the meridian. Passy ; March 17, 1825 ; Seven-feet Equatorial. 6th and 8th magnitudes. Position = 28° 37' sf\ 5 Obs. I DifF. = 0° 16' 7 Distance rs 3' 20". 546 j 5 Obs. | DifF. sr o".9i3 y • • • • At six o'clock in the evening the thermometer stood at 31**; it now stands at 24®. The hoar frost is accumulating rapidly on the polar axis, and on the undefended part of the telescope ; but the object-glass, which has not required wiping through- out the night, remains perfectly transparent. Mean Result. Position 82** 36^ sf'. Distance s' 2o".304 ; Epoch 1825.20. No. DCXIII. R. A. io»^ 39"^ ; Decl. 14" 41' S. Struve, 367 ; P. X. 159 ; Double ; 8th and 10th magnitudes ; small, blue. Passy ; February 23, 1825 ; Seven-feet Equatorial. DifF. 0052' ) j^-a- ^^ Passy ; March 19, 1825 ; Seven-feet Equatorial. 8th and Uth magnitudes. Position = 79 4' n/ 1 5 Obs. I Diff. = i° 5' ) ^ difficult Distance = 3i".904 | 5 Obs. | DifF. = o".72i ] ^ ^^"^cult. Stars of low altitude rather obscure, and are very unsteady. Mean Result. Position 78*> 57' nf\ Distance si"-65i ; Epoch 1825.17. Position = 78° 5 1' n /" I 5 Obs. Distance = 3i".399 | S Obs. and positions 0/4,58 double and triple stars y ^c. 163 No. DCXIV. R. A. io»» 39" ; Decl. 14° 20' S. Struve, s68 ; Hist. Gael. 331. Triple ; A of the 8th, B 8^, and C of the 6th magnitudes. Measures of A B. Blackman-street ; April 18, 1824 ; Five-feet Equatorial. Position = 72° 21' sp\ $ Obs. J Diff. = i° 25' ) Distance = 6".986 | 5 Obs. | DiiF. = o".82i > • • • • Passy ; March 19, 1825 ; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 72** 32' sp Distance = 7".S38 5 Obs. 5 Obs. Diff. = 2^21' \ Diff. =:o".4563 Measures of A C. Blackman-street ; April 18, 1824 ; Five-feet Equatorial. 8th and 6th magnitudes. Position = 6^'>2Q'sp I 5 Obs. I Diff. = 0O42' ") Distance = 1' 18 .216 | 5 Obs. | Diff. = o".6oo j * V * * (C being south of A.) Passy ; March 19, 1825 ; Seven-feet Equatorial. 8th and 7th magnitudes. Position = 68° 50' sp I 5 Obs. i Diff. = 0° 53') Distances 1' i7''.5o6 | 5 Obs. | Diff. = i^oio) • • • • (The star C being to the south of A.) Mean Result. of A B. Position 72° 26' sp ; Distance 7". 262 ; of AC. Position 68** 44' sp ; Distance 1' 17^.861 ; Epoch 1824.75. i64 Mr. South's observations of the apparent distances No. DCXV. R. A. lo*- 39"^ ; Decl. 13° W S. Nova ; Double; 10th and 11th magnitudes. Passy ; February 24, 1825 ; Seven-feet Equatorial. Position=88<'39'n« I 5 Obs. I DifF.= 1° 14' 7„ ^ i j-o: i* Distance=i' 26^024 | 6 Obs. | DifF.= i".ilo pxtremely difficult. Passy ; March 24, 1825 ; Seven-feet Equatorial. lOth and 1 1th magnitudes. Mean Result. Position 88** 44' np ( lo Obs.) ; Distance 1' 26".o78 (11 Obs.) ; Epoch 1825.18. No. DCXVI. R. A. lo*^ 43™ ; Decl. 8° 25' N. Struve, 369 ; P- X. 179. Double ; 9th and 11th magnitudes. Blackman-street ; April 19, 1824 ; Seven-feet Equatorial. Position = ^5° 16' no I c Obs. I DifF. = 2® 58' ) ^^ . , ,.«- ,, Distance= \\\hz ^ \ 5 Obs. | DifF. = o".937 5 Excessively difficult. The night is very bad ; I have little confidence in the accuracy of the observations. Passy; March 26, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = ic° •?!' n» : c Obs. 1 Diff. = 2° 18' 7 ^ , , ,.«. ,^ Distance = i2".484 1 5 Obs. | DifF. = o^^z \ Extremely difficult. Passy; March 28, 1825; Seven-feet Equatorial. Qth and 10th magnitudes. Distance = \i".go'j j 5 Obs. | DifF. = i".zoz. Excessively difficult. Passy ; March 29, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 35° 17' np Distance =1 i2".5o8 5 Obs. 5 Obs. Diff - o" %\ \ Extremely difficult. The small star is blue, and bears but the slightest illumination. Mean Result. Position 35°Qi' np {15 Obs.) ; Epoch 1824.92 ; Distance i2".5io (20 Obs.) ; Epoch 1825.00. and positions of ^s% double and triple stars, &c. 165 No. DCXVII. R. A. io»^ 45- ; Decl. 1° 17' S. Struve, 370 ; Hist. Gael. 227. Double; 6th and 10th magnitudes; small, decidedly blue, and bears but a feeble illumination. Blackman-street ; March 12, 1824 ; Five-feet Equatorial. Position = 86° 57' sf Distances 35". 113 c Obs. I DifF. = 0° 45' i r^^ai u r\u T\a: » i Difficult. 5 Obs. I Diff. = o .4743 Blackman-street; April 2, 1824; Five-feet Equatorial. 6th and 10th magnitudes. Position = SS'* 38' sf\ 5 Obs. Distances 35".333 j 5 Obs. DifF. = 2<* 25' ) ,, ,.«. ,^ Diff. = o".632j^^^^'®'"^^- Small star blue, and bears a very indifferent illumination of the micrometer wires. Mean Result. Position 87^47' sf; Distance 35".223 ; Epoch 1824.22. No. DCXVIII. R. A. 10*^ 47°^ ; Decl. 20° 9' S. Nova ; Double ; 10th and loi magnitudes ; bear but little illumination. Passy ; March 26, 1825 ; Seven-feet Equatorial. Position =54° 13' sp I 5 Obs. I Diff.=o° 46' ) £„._._,„ ^y^.^,, Distances: I' i8".o6i | 5 Obs. | Diff. = i".875 5 ^"^emely diflicult. Passy ; March 28, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. Position =54'' 21' sp I c Obs. I Diff, = i° 40' ) ^ . , j.^- ,^ Distances I' I9''.254 | 5 Obs. | Diff.=2".j84l Excessively difficult. Both stars very indistinct. Passy; March 29, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. Distance = 1' i9''.989 j 5 Obs. | Diff. = i"-923. Excessively difficult. On the admission of the smallest quantity of light, the stars become scarcely visible. Mean Result. Position 54** 16' sp (lo Obs.) ; Distance i' 19*101 (15 Obs.); Epoch 1825.23. i66 Mr. South' s observations of the apparent distances No. DCXIX. R. A. io»» 5T ; Decl. S** o' N. Struve, 375 ; 11- 78. Double; 8th and isth magnitudes. Passy ; March 29, 1825 ; Seven-feet Equatorial. c Obs. I Diff. = 4° 8' ) „ ' ^ A-tc 1. S Obs. I DifF. = J".673i Excessively difficult. Position = 72° 38' sf Distances: 8".762 The small star is of a light blue colour, and cannot be seen except when the night is extremely favourable. Passy ; April 27, 1825 ; Seven-feet Equatorial. 8th and 1 1th, or 12th magnitudes. The small star under the most feeble illumination is visible only with the greatest attention ; the measures, I fear, merit but little confidence. Passy ; May 7, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position = 74° 14' «/| 5 Obs. | DifF. = 1° 53'. Excessively difficult. Mean Result. Position 74** 1' sf\ (15 Obs.) ; Epoch 1825.30 ; Distance 8^637 {10 Obs.); Epoch 1825.28. Sir W. Herschel measured this star in 1783 and in 1803, the respective positions being 75" 21' 5/ and 71° 42' sf. The mean (73° 32') differs only o" 29' from that here stated, so that this star may be presumed liable to no change in position. (H.) and positions of 4,58 double and triple stars, &c. 167 No. DCXX. R. A. io»» 58" ; Decl. 12*» 28' S. Nova ; Double ; 8th and 10th magnitudes. Passy ; April 19, 1825 ; Seven-feet Equatorial. * Position = 73° 6'nfls Obs. | DiflF. = o° 30'. Extremely difficult. The night now so unfavourable, that observations of distance are impracticable. Passy ; April 27, 1825 ; Seven -feet Equatorial. 8th and 10th, or 1 1th magnitudes. , Position = 73° 31' «/| 5 Obs. I Diff. = 1° 28' ) ^ ^ , ..«: ,^ Distance = 32".774 I S Obs. | DiflF. = o".553 J Extremely difficult. Passy ; April 29, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position = 73° 19' n/l 5 Obs. I Diff.= 2° 3' ) „ . , ,.«. ,^ Distance = 32".623 | S Obs. | Diff.= o".4o8j E««sively difficult. Mean Result. Position 73° 19' nf(i5 Obs.) ; Distance 32".698 (10 Obs.) ; Epoch 1825.31. No. DCXXI. R. A. 11^ 0"^ ; Decl. 66^ 59' N. Struve, 377 ; 1790.386. Triple ; A 9th, B 97, and C of the 8th magnitudes. Measures of A B. Passy ; February 24, 1825 ; Seven-feet Equatorial. Position =64° 35' nf 5 Obs. I Diff. = i° 25' ^ „ ,, ..«. ,, Distance=4l".327 S Obs. 1 Diff. = o".336 J ^^^her difficult. Thermometer stands at 30° ; no dew on the object-glass, but the polar axis is very wet. Passy ; Febi-uary 25, 1825 ; Seven-feet Equatorial. . , 9th and 9^^ magnitudes. Position = 640 26' nf\ 5 Obs. I Diff. = 0° 28' ) T^•n: 1 Distance = 43".534 | 5 Obs. | Diff. = o''.456 ] I^^^^ult. 168 Mr, South's observations of the apparent distances No. DCXXI. continued. Measures of A C. Passy ; February 25, 1825 ; Seven-feet Equatorial. ^ 9th and 8th magnitudes. Position = 26° 40' ra JO I 3 Obs. I DifF. = o® 15' \ p, . Distance = 3' 21 ".979 | 2 Obs. | DiiF. = o".264 f "^^^^^Y- Night is become bad ; no more observations can be gotten. Passy : March 21, 1825 ; Seven-feet Equatorial. 9th and 8th magnitudes. Position = 260 31' np \ 5 Obs. DifF. = 0° 22' 7 Distance = 3' 2 3". 270 | 5 Obs. DifF. = i".563 3 * * * * The star C being to the north of A. Passy ; March 26, 1825 ; Seven-feet Equatorial. 9th and 8th magnitudes. Distance = 3' 23'.620 | 5 Obs. j DifF. =; i".298 Mean Result. of AB. Position 64"So'w/; Distance 43".43i ; Epoch 1825.14. of A C. Position 26° 34' np (8 Obs.); Epoch 1825.18 ; Distance 3' 23^.201 (12 Obs.); Epoch 1825.19. No. DCXXII. R. A. 1 1^ 3" ; Decl. 74** 26' N. Struve, 378; 1790.389. Double ; 9th and 9j magnitudes, and bear but a very feeble illumination. Blackman-street ; April 11, 1824; Five-feet Equatorial. Position = 26° 15' «P I 5 Obs. DifF. = 2° 42' { p.-^-^ ,. Distance = I2".S5 1 j 5 Obs. DifF. = 1 ".1685 ^'*^"^*- Blackman-street; April 12, 1824; Five-feet Equatorial. 8| and d\ magnitudes. Position = 26° lY np\ $ Obs. DifF. = 1° 12' 7 T>:ffl^„i4. Distance = i2".4o8 | 5 Obs. DifF. = i".3s8 | ^^™'^"'^* Mean Result. Position 26° 16' np'. Distance i2".479 ; Epoch 1824.28. and positions 0/4,58 double and triple stars, ^c. 169 No. DCXXIII. R. A. iiJ* 6™ ; Decl. 28<» ss'N. Struve, 379 ; Hist. C«l. 61 ; Double ; 9^ and 10th magnitudes. Black man-street ; March 13, 1824; Five-feet Equatorial. Position = 5° 13' «/ 5 Obs. Diff. = 3° '6' ] Very difficult. Distance = +".024 5 Obs. DifF. = o .348 ) ^ Blackman-street ; April 2, 1824 ; Five-feet Equatorial. 8th and 9th magnitudes. Position = 5^ 14' */| 5 Obs. I Diff. = z^o' | j^.^^^^^ Distance = 4'. 182 | 5 Obs. } Diff. = o".649 ) Night very favourable. Mean Result. Position 5** 13' nf; Distance 4". 103 ; Epoch 1824.22. No. DCXXIV. R. A. ii'* 10™ ; Decl. 0° 40' S. Struve, 383 ; Hist. Gael. 498. Double ; 8th and Sj magnitudes. Blackman-street ; April 11, 1824; Five-feet Equatorial. Position = iS°o' sp\ 5 Obs. Diff. =t 2« 3' ) Distance = io".o 11 | 5 Obs. Diff. = o".442 j Blackman-street; April 12, 1824; Five-feet Equatorial. 8th and 8| magnitudes. Position = i8«» 3' «/) 1 5 Obs. Diff. = i« 13' \ Distance = io".28o | 5 Obs. Diff. = o".379 J ♦ • • • Mean Result. Position 18° 1' sp; Distance io".i45 ; Epoch 1824.27. MDCCCXXVI. ^ 1 70 Mr. South's observations of the apparent distances No. DCXXV. R. A. ii** io» ; Decl. 15° 16' N. Struve, 382 ; Hist. Gael. 223. Double; 8th and 10th magnitudes. Blackman-street ; April 11, 1824 ; Five-feet Equatorial. Position = 790 33' nf\ 5 Obs. I DifF.= 2° 37' 1 oj^.^,. Distance = 5".2 11 J 5 Obs. | DifF. = o".s6g ] •^^"^'^"'^• Blackman-street; April 12, 1824; Five-feet Equatorial. 7tli and 8| magnitudes. Position =78° 20' nf Distance = 4". 362 5 Obs. 5 Obs. DifF. = i«» 33' ) Diff. =o".4745 Passy ; March 26, 1825 ; Seven -feet Equatorial. 8th and 9th magnitudes. Position = 81° 7' «/ Distance = 5 ".20 7 5 Obs. 5 Obs. Diff. = 0° 45' ) DifF. = o".625 The distance observed April 1 2, 1 824, does not well accord with cither of the sets ; at the same time nothing appears in the rough journal to invalidate the accuracy of the former ; on the contrary, it would seem that the stars were brighter on that night, than on either of the other nights of observation : the discordant series therefore cannot be rejected with propriety. Mean Result. Position 79° 40' nf {15 Obs.) ; Distance 4^927 (i5 Obs.) ; Epoch 1824.60. No. DCXXVI. R. A. ii'' 19™ ; Decl. 40° 20' N. 57 Ursse Majoris ; Struve, 388 ; III. 86. Double ; 8th and loth magnitudes ; small, blue, and bears a very good illumination. Passy ; March 29, 1825 ; Seven-feet Equatorial. Position =8o°5'n/ Distance ;=6".342 5 Obs. 5 Obs. DifF. = Diff. •.=:o''5i'7 '. = o".2i6 j and positions 0/4,58 double and triple stars y &c. 171 No. DCXXVI. continued. Passy ; April 5, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position r= 79° 26' nf Distances 6". 246 5 Obs. I DifF. =: 2° o' = 2° o' i 5 Obs. I DifF. z= ©".72 1 ) • • • • Mean Result. Position 79° 45' w/; Distance 6".294; Epoch 1825.25. In 1783 the position of this star is stated by Sir W. Herschel to have been 75° 36*' nf. It will remain to be decided by future measures whether the difference, 4° 9', between this and the present angle, arise from a real very slow change in the stars themselves, or from error of observation. (H.) No. DCXXVIL R. A. iiJ^ 21™ ; Decl. 16° 26' S. Nova ; Double ; 8^ and 9th magnitudes. Passy ; March 18, 1825 ; Seven feet Equatorial. DifF. = 0° 17' ) DifF. =o".48i5 • • • • Position =60° iz'np Distance = 29".254. 5 Obs. 5 Obs. Passy ; March 26, 1825 ; Seven-feet Equatorial. Equal ; each of the 8th magnitude. Position = 61° 1 1' sfox np 5 Obs. DifF. = 0° 54' ) Distance = 28".6i7 5 Obs. DifF. = o".625 5 Passy ; March 28, 1825 ; Seven-feet Equatorial. Equal ; each of the 9th magnitude. Position = 60" 52' tip or *y I 4 Obs. | DifF. =; 0° 12'. . . Night is become cloudy ; no more observations can be procured. Passy ; March 29, 1825 ; Seven-feet Equatorial. Equal ; each of the 8th magnitude. Position = 60° 46' np or */ 1 5 Obs. DifF. = 1® 35' ) Distances zi)".ooj I 5 Obs. DifF. = i''.oio ) Mean Result. Position 60° 45' np or 5/(19 Obs.); Epoch 1825.25 Distance 28".939 (15 Obs.) ; Epoch 1825.24, 172 Mr. South's observations of the apparent distances No. DCXXVIII. R. A. 11^ 21"" ; Decl. 60" 40' N. Struve, 389; 1790; 381. Double ; 8th and 8|- magnitudes. Blackman-street ; April 11, 1824 ; Five-feet Equatorial. Position = 0° 26' sf \ 5 Obs. | Diff. = 2" 1 3'. Blackman-street; April 12, 1824 ; Five-feet Equatorial. 8th and J)th magnitudes. Position s=o° 18' sf Distance = iS"-°S3 5 Obs. 5 Obs. DifF. = 0° 26' ) DitF. = o".649J Blackman-street; April 17, 1824; Five feet Equatorial. 8th and 9th magnitudes. Distance = 13^.028 | 5 Obs. | DifF. =0". 3 36. Mean Result. Position 0° 22' sf; Distance 13^.040; Epoch 1824.28. No. DCXXIX. R. A. ii»> 28™ ; Decl. 22° 25' N. Nova; Double; 10th and 11th magnitudes. Passy ; May 5, 1825 ; Seven-feet Equatorial. Position = S\fSnp± I 5 Obs. I Diff. = ij f \ ^,,,,,;y,i difficult Distance = 4+ '.159 ± | 5 Obs. | Diff. = 3 .775 S ^ Unless these should be corroborated by subsequent observations, I consider them entitled to very little confidence ; neither star will bear any illumination. Passy ; May 9, 1825 ; Seven-feet Equatorial. 10th and 1 1th magnitudes. Position =50 37' np i 5 Obs. Diff.= 0° 32' 1 Excessively difficult. Distance=44 .919 | 5 Obs. Diff.= o.84i) ^ Under the most feeble illumination, both stars become invisible. Passy; May 10, 1825; Seven feet Equatorial. , loth and 12th magnitudes. Position = 5° 4.' np 5 Obs. Diff. = i; 6' j E^^esssively difficult. Distance = 44' .044 5 Obs. Diff. = 1 .370) ' Mean Result, Position 5° 34/ np (15 Obs.) ; Distance 44''.374 (i5 Obs,); Epoch 1825.35. and positions of 4f5S double and triple stars, (f.e, j-76 No. DCXXX. R, A. ii*^ 30" ; Decl. 2f ai N- Struve, ^99. ; Hist. Casl. 64 ; Double; iith and 12th magnitudes. Rlackman-street ; April 19, 1824; Seven -feet Equatorial. Position = 3° 56' nf I 5 Obs. Djff. = i° 38' J Extremely difficult. Distance = 5".684 | 5 Obs. Dift. = o .505 ^ ^ Under a very slight illumination of the micrometer wires, these stars become invisible. Passy; March 26, 1825 ; Seven-feet Equatorial. 11th and 12th magnitudes. Position = 4° 3' nf 5 Obs. i Diff. = 3° 20' ^ gxtremelv difficult Distance = 5".50i 5 Obs. | DifF. = o".649 5 Extremely dimcuit. The small star is light blue, and neither of them will bear scarcely any illumination. Mean Result. Position 4**o' nf\ Distance ^'.S9^ \ Epoch 1824.76. No. DCXXXI. JR. A. 11'' ^9"^ ; Decl. 68° 19' N. Struve, 2^96 ; Hist. Casl. 385 ; Double ; 8th and 9th magnitudes. Blackrnan-street ; April 14, 1824 ; Five-feet Equatorial. Position =89° 4' «/ j 5 Obs. Distances 1 1".7 1 3 ) 5 Obs. Diff. = »* 35' ) Diff.=o".7;,8> Blackman-street ; April 17, 1824 ; Five-feet Equatorial. 8th and 9th magnitudes. Position = 89" 3' */ j 5 Obs. j Diff. = 2° 20' ) Distance = 1 1".97 8 j 5 Obs. j Diff. = i".i68| • • • • Mean Result. Position 89° 4' sf\ Distance ii".845; Epoch 1824.29. 1 74 Mr. South's observations of the apparent distances ^ No. DCXXXII. R. A. i\^ 43" : Decl. 9° 48' N. Struve, 396 ; IV. 49 ; Double ; 7t and 8th magnitudes. Blackman-street ; April 14, 1824 ; Five-feet Equatorial. Position = 61° 53' *;; I 5 Obs. I DifF. = 0° 51' J Distance = 3o".34i | 5 Obs. | Diff. = o".7275 • • • • Blackman-street ; April 17, 1824 ; Five-feet Equatorial. 7th and 9th magnitudes. Position = 6i® 35' sp I 5 Obs. I DifF.=o° 48' \ Distance =30". 1 89 | 5 Obs. | DifF.=o".885> • • • • Passy ; April 7, 1825 ; Seven-feet Equatorial. 7th and 9th magnitudes. Distance=3o".6i5 I 5 Obs. I Diff. = o".336 Observed on the meridian. Mean Result. Position 61° 44' 5/) (10 Obs.) ; Epoch 182429 ; Distance 30^382 (15 Obs.); Epoch 1824.62. ' In 1783 the position is stated to have been 56° 30' sp, and the distance 2 7". 50. An error of observation to the extent of 5° 14' is too much to be supposed in a star of the 4th class, and it is therefore pretty clear that this star is liable to a slovr change ; whether arising from orbitual motion in both, or rectilinear in one of the two, future observations must decide. (H.) and positions of ^58 double and triple stars, &c, 175 No. DCXXXIII. R. A. 11'* 56"^ ; Decl. 52° 55' N. Struve, 401 ; 1790; 376- Double ; 8th and S^ magnitudes. Blackman-street ; April 14, 1824 ; Five-feet Equatorial. Position = 4® 26' sf Distance = 8 ".309 5 Obs. 5 Obs. DifF. = 2° 24' 7 Diff. = o".4ii3 • • Blackman-street; April 17, 1824 ; Five-feet Equatorial. 8| and 9th magnitudes. Position = 4° 25' sf Distance = 8". 309 5 Obs. 5 Obs. Diff. = 2*' 13' \ Diff. = o'.egs 5 Mean Result. Position 4° 26' sf Distance 8".309 ; Epoch 1824.29. No. DCXXXIV. R. A. 12'' a"" ; Decl. 15° 48' S. Struve, 402 ; Hist. Csel. 232. Double ; 8th and 10th magnitudes. Blackman-street ; April 14, 1824; Five-feet Equatorial. Position = 7° 21' n/> I 5 Obs. ^'^ — '•° ^' Distance == f.Czi \ 5 Obs. Diff: = o°^2} Very difficult. Blackman-street ; April 17, 1824 ; Five-feet Equatorial. 8^ and lOth magnitudes. Position = 6o 45' np I 5 Obs. I Diff. = 2° 15' } difficult. Distances 8".322 | 5 Obs. | Diff. = o .758) The small star is blue, and bears but a very feeble illumination. Mean Result. Position 7° 3' np; Distance 7".97i ; Epoch 1824.29. it6 Mr. South* s observations of the apparent distances No. DCXXXV. R. A. i9> 2™; Decl. 1° 15' S. Nova; Double ; 10th and 11th magnitudes. Passy ; May 5, 1825 ; Seven-feet Equatorial. Position =: 6° 39' n p 5 Obs. j DifF. = 2" 47' 7 Extremely difficult. Distance = 23".745 5 Obs. | DifF. = o".865 j Excessively difficult. Measures perhaps a little suspicious, although taken with great care. Stars are tolerably steady, but will scarcely bear the slightest illumination. Passy ; May 9, 1825 ; Seven-feet Equatorial. 10th and 1 2th magnitudes. Position = 7° 30' n p 1 5 Obs. Distance =: 23".6oi | 5 Obs. Eiff. = i '.2^2} Excessively difficult. These results were procured under the most favourable circumstances ; the stars were on the meridian, and very steady; yet ffom the extreme faintness of the smaller star, some inaccuracy may be apprehended. Mean Result. Position 7'*4'w/>; Distance 2 3". 673 ; Epoch 1825.34. No. DCXXXVI. R. A. 12'' 6» ; Decl. io° 58' N. Nova ; Double ; 9! and 1 oth magnitudes. Passy ; March 7, 1825 ; Seven-feet Equatorial. Position 24° 29' sp \ 5 Obs. '; DifF. = 0° 20'. Vfery difficult. Stars very steady ; but the night so hazy, that satisfactory measures of distance fcanhot be obtained. Passy ; March 26, 1825 ; Seven-feet Equatorial. lOth and 1 1th magnitudes. Position = 24° S^ ^P j 5 Obs. 1 DifF. == 1° 57' ) Very difficult. Distance f= 26 '.694 j 5 Obs. j DifF. zz i".%^\ \ Extremely difficult. Passy ; March 29, 1825 ; SeVen-feet Equatorial. 9^ and 10th magnitudes. Position = 24^* 29' sp I 5 Obs. I DilF. = 0° 59' \ Very difficult. Distance = 26".467 j 5 Obs. | DifF. = 0^432 j Extremely difficult. Neither star bears a good illumination. Mean Result. Position 24° 37' sp ; Epoch 1825.22 ; Distance 26".58o ; Epoch 1825.23. and positions 0/4.58 double and triple stars, ^c. 177 No. DCXXXVII. R. A. is!> 18- ; Decl. 18° 58' S. Nova ; Double; 10th and 12th magnitude.*?, and bear but the slightest illumination. Passy ; May 5, 1825 ; Seven-feet Equatorial. Diff. = 0° 32' 1 Extremely difficult. DifF. = i".202) Excessively difficult. The measure of distance may perhaps be liable to an error of two or three seconds, from the extreme faintness of the small star. Position = 6j° 26' sp j 5 Obs, Distance = 1' z".S7^ \ 5 Obs. Passy ; May 9, 1825 ; Seven-feet Equatorial. lOth and 12th magnitudes. Position = 66° 34' sp 5 Obs. Diff. = 2° 27' ^ ^ . , ,.^ ,^ Distance = I' 1'' 423 5 Obs, Diff. = i«.563 j ^'^""^^^^y ^^^^^^^- Results probably suspicious j both stars become invisible under an illumination just sufficient to show the situation of the wires. Passy ; May 10, 1825 ; Seven-feet Equatorial. lOth and 12th magnitudes. Position rr 66° 41' sp Distance = i' o".904 5 Obs. \ Diff. = 0° 25' I ^ . , .. ~ , 5 Obs. 1 Diff = o".6oi j Excessively difficult. Observations made with great care ; but the obscurity of the stars is such, that • coincident measures must not be expected. Mean Result. Position 66° 54' sp ; Distance i' i".6s5 ; Epoch 1825.35. No. DCXXXVIII. R. A. 12^ 20" ; Decl. 26° 54' N. Nova ; Double ; 6th and 7th magnitudes. Passy ; March 26, 1825 ; Seven-feet Equatorial. Position zr 18° 58' *;> I 5 Obs. ( Diff. = i® 8' 7 «, , Distance = 2' 24".5oi | 5 Obs. | Diff. zz o".9i3 j ^^'^"^ulous. Passy ; March 29, 1825 ; Seven-feet Equatorial. Position = 19° 28' sp I 5 Obs. | Diff. = o« 16' Kt , , Distance = 2' 2^".S7z \ 5 Obs. | Diff. = i".202 5 Unsteady. Mean Result. Position 19° is' sp'. Distance 2' 24".436 ; Epoch 1825.23. MDCccxxvi. a a 178 Mr, SouTH*s observations of the apparent distances . No. DCXXXIX. R. A. lo,^ 29°* ; Decl. 3° 23' S. Struve, 418 ; V. 129. Double; 8th and 13th, or 14th magnitudes. Passy ; May 7, 1825 ; Seven-feet Equatorial. Position =14° 57'^/ 1 5 Obs. DifF.= i°4' ) Ousoicious Distance = 49".6i8 | 5 Obs. Diff. = 2".2i2 J Auspicious. The night is very fine, but the measures are excessively difficult ; the small star can only be seen with considerable attention. Passy; May 8, 1825; Seven-feet Equatorial. 8th and 12th, or 14th magnitudes. Position = 16° o' sf} s Obs. DifF. = 1° 9' ) tj ^ • ,• a-m ^^ Distance^r: Si-'-z+e-^ | 5 Obs. DifF. - i".o8z J Excessively difficult. The small star is so extremely indistinct, that the measures must be considered ' somewhat dubious. Night favourable. Passy; May 10, 1825 ; Seven-feet Equatorial. 8th and 12th, or 13th magnitudes. ^lliSc" ^ \t4:/ 1 I 8S: [ ?f£ Z i".6o*; } Excessively difficult. Night fine, but the small star will scarcely bear any illumination. Mean Result. Position 15** 22' sf; Distance 50". 555 ; Epoch 1825.36. Sir W. Herschel has no measures of the angle of position of this star. (H.) and positions of 4,58 double and triple stars, ^c. 179 No. DCXL. R. A. 12^ QQ'^ ; Ded. 4° 22' S. Nova ; Double; 10th and 12th magnitudes ; neither star bears but the most feeble illumination. Passy ; May 5, 1825 ; Seven-feet Equatorial. , Position = 5° 32' sf\ 5 Obs. I Diff. =: 6° 15' 7 Excessively difficult. Distance rz 10'. 392 \ 5 Obs. | Difr. ir i .202 3 ' These results must not be regarded with much confidence j the stars become invi- sible, under almost the slightest illumination. Passy ; May 9, 1825 : Seven-feet Equatorial, llth and 12th magnitudes. Position = 6" 9' sf Distance = io".oo2 Obs. 1 Diff. = 3; 35' J Excessively difficult. Obs. I Diff. = o".432 5 ' The distance, in consequence of the indistinctness of each star under illumhiatioa must, I fear, be received with distrust. Mean Result. Position 5° 50' sf\ Distance io'''.i97 ; Epoch 1825.35, No, DCXLI. R. A. 19^ 36"; Decl. 15° 20' N. Nova ; Double ; 8th and 8^- magnitudes. Passy; April 15, 1825 ; Seven-feet Equatorial. Position =r 56° 44' «p Distances 33".267, 5 Obs. Diff. = 0° 39' i Unsteady 5 Obs. Diff. = i".322 5 'Unsteady, Passy ; April 24, 1825 ; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 56° 27' sp I 5 Obs. Diff. = 0° 42' | <>. j Distances 33^452 j 5 Obs. Diff. = o".288 j ^^^^^y* Mean Result. Position 56° 35' sp ; Distance ss"S59 ; Epoch 1825.30 i8o Mr, South' s observations of the apparent distances No. DCXLII. R. A. 12^^ 40"* ; Decl. 14° 58' N. Nova ; Double ; 8^ and 11th magnitudes. Passy ; May 5, 1825 ; Seven-feet Equatorial. Position =53° 50' nf Distance := 54".3o6 5 Obs. I DifF. = 2° 12' ) Very difficult. 5 Obs. \ Diff. r: i'".923 ) Extremely difficult. The small star will scarcely bear the slightest illumination. Passy ; May 7, 1825 ; Seven-feet Equatorial. 8 J and 12th magnitudes. Position = 53° 51' nf\ 5 Obs. Diff. = 2° 58' ) Excessively difficult Distance = 54".S37 | 5 Obs. Diff. = i".49i ] ^^^ssiveiy aimcuit. The small star only seen with great attention. Night fine. Mean Result. Position 5S° 6o'nf; Distance 54".42i ; Epoch 1825.34. No. D CXLIII. R. A. 12^ 44™ ; Decl. 17° 4' S. Nova; Double ; 8th and 9th magnitudes. Passy; March 26, 1825 ; Seven-feet Equatorial. Position = 25° 26' np Distance = 23".433 5 Obs. I Diff. = 1° i' ) On the meridian, but 5 Obs. I Diff. = I ".1 54) very tremulous. Passy ; March 29, 1825 ; Seven-feet Equatorial. 8th and Qth magaitudes. Position r= 25° o' np I 5 Obs. | Diff. = o'' 44' | tt__.-_j^ Distance = 23".9io | 5 Obs. | Diff. = o';72i j Unsteady. Position = 25° 5' np Distance = 2 3". 2 28 Passy ; April 11, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes ; small, blue. Dbs. Diff. = 1° 20' } Very difficult. Dbs. Diff. = i".o82 5 Extremely difficult. The small star is very obscure, and bears but a very feeble illumination. Passy ; April 12, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes ; the small star is very faint. Position = 24° 46' wj) 1 5 Obs. I Diff. = 2° ii' ) Extremely difficult. Distances: 23".467 j 5 Obs. | Diff. = o".9i3 5 Excessively difficult. Mean Result. Position 25° 4' np (20 Obs.); Distance 23^509 (20 Obs.); Epoch 1825.26. and positions of ^sS double and triple stars, ^c. 181 No. DCXLIV. R. A. 12^ 51°' ; Decl. 15° 18' N. Nova ; Double ; 9th and 11th magnitudes. Passy ; May 6, 1825 ; Seven-feet Equatorial. Position = 8|0 22' sp I $ Obs. I Diff. = i® 9' > Very difficult. Distance ■= zf'.zoS \ 5 Obs. j DifF. = 2",i6^l Extremely difficult. Results perhaps a little suspicious ; the larger star bears but a feeble, and the smaller scarcely any illumination, Passy ; May 7, 1825 ; Seven-feet Equatorial. 9th and 12th magnitudes. Position =: 80° ^6' sp Distance = 27'. m 5 Obs. I DifF. = 1° 42' \ Extremely difficult. 5 Obs. I Diff. = i".49i ) Excessively difficult. Observed when on the meridian. Night fine. Mean Result. Position 81° 9' sp; Distance 21^.159; Epoch 1825.34. No. DCXLV. R. A. 12*^58'" ; Decl. 1° S5' N. Nova ; Double ; 8th and 8-|- magnitudes. Passy ; April 12, 1825 ; Seven-feet Equatorial. Position = 85° o' n/l 5 Obs. I Diff. =: o° 58' } Very steady and Distances 8".2i3 | 5 Obs. | Diff. = o".8i7 j well defined. Passy ; April 15, 1825 ; Seven-feet Equatorial. 8th and 8^ magnitudes. Position = 84° 36' nf 5 Obs. j Diff. z= 2° 5' ) Occasionally well defined. Distance = 7".983 5 Obs. Diff. = o".793 j but very unsteady. Variable refraction so extremely troublesome, that I am compelled to relinquish observing. Mean Result. Position 84" 48' nf; Distance 8".o98 ; Epoch 1825.28. i82 Mr. South' s observations of the apparent distances No. DCXLVI. R. A. isM" ; Decl. 16° 25' N. Nova ; Double ; 9th and 10th magnitudes. Passy ; May 5^ 1825 ; Seven-feet Equatorial. Position = 70° 48' »j? I 5 Obs. Distance = 3".905 j 5 Obs. DifF. = 3° 50' ) Very difficult. DiiF. = o".48i ] Extremely difficult. The smaller star will scarcely bear any illumination. Passy ; May 9, 1825 ; Seven-feet Equatorial. 8^ and 11th magnitudes. Positron = 74° 44' np I 5 Obs. DifF. = 2° 30' ) t;„>.essivelv diffimlt Distance = 4".22 1 \ 5 Obs. Diff. = ©".962 ] Excessively difticult. Observed on the meridian; distances considered a little doubtful. The night is become so unfavourable, that the small star is seen only with great difficulty. Passy ; May 10, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes Position = 73«» 38' np I 5 Obs. I Diff. = 0° 35' ) ^ ^.g. , Distance =4". 145 I 5 O^s. | Diff. = o".4o8 \^^^ aimcuit. Observed when on the meridian ; but the small star does not admit of a good illumination of the wires. Passy ; May 14, 1825 ; Seven-feet Equatorfat. 9th and 11th magnitudes. Position =71° 54' np | 5 Obs. j Diff. = 1° 50'. Excessively difficult. The small star only visible by glimpses, and then very indistinctly j the observa- tions by no means satisfactory. Mean Result. Position 7S° 46^ np (20 Obs,) ; Epoch 1825.38,- Distance 4". 090 (15 Obs.); Epoch 1825.37, and positions of ^^S double and triple stars, 6fr. i8s No. DCXLVII. R. A. 13' i™ ; Decl. 1° 43' S. Nova ; Double ; 8th and 13th magnitudes. Passy ; May 7, 1825 ; Seven-feet Equatorial. ^ Position = 56° 36' sp I 5 Obs. I DifF. = i° 15' > Excessively difficult. Distance = 42".582 [ 5 Obs. | Diff. = i".394i ^^^essiveiy oimcuit. The night is very fine j but the small star is so obscure, that I fear much reliance must not be placed in the results. Passy ; May 14, 1825 ; Seven-feet Equatorial. Position = 55° 42' sp 5 Obs. I DifF. = 1° 3' ^ Excessively difiicult Distance = 43".676 5 Obs. | DifF. = i".i30 ) excessively aimcuit. Stars of the 8th and 13th, or 14th magnitudes : the smaller one scarcely bears the least illumination. Observed on the meridj^n. Night fine. Mean Result. Position sQ° 9' sp ; Distance 43". 129 ; Epoch 1825.36. No. DCXLVIII. R. A. 13' 5" ; Decl. 19° o' N. Nova ; Double ; 10th and 12th, or 13th magnitudes. If this star be brought into the upper part of the field, a nebula of consi- derable magnitude w^ill be found in the low^er part of it. Passy ; May 10, 1825 ; Seven-feet Equatorial. l8b::|g;ff:l°°.l^s}E««siveiHifficuit. Position — 25° 55' nf Distance = i' 27". 847 ; These stars are so extremely faint, that measures of accuracy cannot be obtained. Night fine. Passy ; May 14, 1825 ; Seven-feet Equatorial. lOth and 13th magnitudes. Position = 25° z' nf 14 Obs. Distance = 1' 32". 175 ± | 2 Obs. Diff! = VM^\ Excessively difficult. The small star is so extremely indistinct, that the measures are very unsatisfactory j those of distance are to be regarded as mere approximations. 184 Mr. South* s observations of the apparent distances No. DCXLVIII. continued. Passy ; May 31, 1825 ; Seven-feet Equatorial. lOth and 14th, or 15th magnitudes. 2 Obs. DifF*. = o".6;9 ± ] Excessively difficult. Position = 25° 7' «/ ] 4 Obs Distance = 1' 26".888 ± Night fine, but observations very liable to error, in consequence of the extreme faintness of the stars. Mean Result. Position 35° 22' nf; Distance 1' 28".970 ; Epoch 1825.38. No. DCXLIX.* R. A. 13^ 22"" ; Decl. 60° 53' N. y 426 (Bode) Ursse Majoris ; Struve, 440 ; VI. 22. Double ; 6th and 9th magnitudes. Blackman-street ; April 17, 1824 ; Five-feet Equatorial. Position = 20° 57' sf\ 5 Obs. j DifF. == o" 22' ) Distance = 3' i".373 J 5 Obs. | DifF. = i".263 J • • • • Blackman-street ; April 18, 1824 ; Five-feet Equatorial. 6th and 9th magnitudes. Position = 21° 6' */| 5 Obs. I DifF. = 0° 41") Distance = 3' i".6i7 j 5 Obs. \ DifF. — i".263 J • • • • Mean Result. Position 21** 2' sf; Distance 3' i''.495 ; Epoch 1824.30. Sir W. Herschel has no measures of this star. (H.) and positions 0/4,58 double and triple stars, &c. 185 No. DCL. R. A. 13*^ 25" ; Decl. la** ss' S. Nova ; Double; 83 and 11th magnitudes. Passy ; May 5, 1825 ; Seven-feet Equatorial. Position == 59** 1 1' */ i 5 Obs. DifF. = 1° 26' ) Very difficult. Distance = 4S".852 | 5 Obs. DifF. = o".24o3 Extremely difficult. The small star becomes invisible under a very slight illumination. Passy ; May 10, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position = 59° 8' «/ 1 5 Obs. I DifF. = 0° 33' > ,, ,. - .^ Distance = ls"'^97 I 5 Obs. | Diff. = o".889 j ^^^ difficult. Observed when on the meridian, but the small star is very faint. Mean Result. Position 59° 10' sf; Distance 4>5"'5^4> ; Epoch 1825.35. No. DCLI. R. A. 13^ 27- ; Decl. 25° 35' S. Nova; Double ; 8th and 8^ magnitudes. Passy ; May 5, 1825 ; Seven-feet Equatorial. Position = 7y° 2' sp \ s Obs. I DifF. =r 2° 8' ) ^t j Distance = io''.363 | 5 Obs. | DifF. = i".4oo5 Unsteady. Within a few minutes of the meridian, when observed. Passy ; May 8, 1825 ; Seven-feet Equatorial. ^ 8th and 8j magnitudes. Position = 7y° 59' sp ] 5 Obs. Diff. = 1° 21' ) ^^ , , , ^ . Distance = io".337 | 5 Obs. Diff. = o".4o8 j tolerably steady. Observed on the meridian. Night fine. Mean Result. Position 77° so' sp ; Distance io".350 ; Epoch 1825.34. MDCCCXXVI. b b 186 Mr. South's observations of the apparent distances No. DCLII. R. A. 13"^ 36"^ ; Decl. 9** 4o' S. Nova; Double ; 9th and 9\ magnitudes ; the smaller star does not bear a very good illumination. Passy ; May 7, 1825 ; Seven-feet Equatorial. Position = 57° 21' «/{ 5 Obs. Distance s= S3"'^4-3 I 5 ^^s. DifF. = I* 18' \ T^-« 1^ DifF. Observed on the meridian. Night very favourable. Passy ; May 10, 1825 ; Seven-feet Equatorial. 9th and 9^ magnitudes. Position = 56° 19' sf 5 Obs. DifF. - 1° z' ) Distance = S^"'°9S 5 Obs. DifF. = o".S6s | ' * * ' Mean Result. Position 56° 50' sf; Distance 53".S69; Epoch 1825.35. No. DCLIII. R. A. 13^^ 38"" ; Decl. 19° 18' N. Nova ; Double; 8th and 11th magnitudes: the small star scarcely bears any illumination. Passy ; May 7, 1825 ; Seven-feet Equatorial. Position = 83° o' «p I 5 Obs. I DifF. = o" 54' ) ,. ^ , ,.«. . Distance = 3o".257 ^ | 5 Obs. | DifF. = C.+Jz \ Extremely difficuh. Observed when 15 minutes east of the meridian. Night favourable. Passy ; May 14, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position = 82*' CO' sp I 5 Obs. 1 DifF. = 1° 50' | ^^^ . , ,.«; ,^ Distance = 3o".778 1 5 Obs. | DifF. = o".36o5 Excessively difhcult. Night fine, but the small star bears only the most scanty illumination. Mean Result. Position 82° 55' sp; Distance 3o".5i7 ; Epoch 1825.36. and positions of 4,58 double and triple stars , &c, 187 No. DCLIV. R. A. 13^ 40™ ; Decl. S9° 25' N. Nova; Double ; 8th and 11th magnitudes. Passy ; April 29, 1825 ; Seven-feet Equatorial. Position = 32° 29' «p I 5 Obs. | DifF. = o° 48' ) Very difficult. Distance = i' io".599 | 5 Obs. | Diff. = o".962 ) Extremely difficult. The small star scarcely bears the slightest illumination. Passy ; May 27, 1825 ; Seven-feet Equatorial. 7th and II th magnitudes. Position =. 31" 57' sp I c Obs. \ DiiF. = 0° 20') ,;- ,.«. ,^ Distance = i' m(o8q 5 Obs. Diff. = i".4gi ( ^'"^ ^'''^^• .089 j 5 Obs. I Diff. = i".49i j Mean Result. Position 32° 13' sp ; Distance 1' 10^^844 ; Epoch 1825.36. No. DCLV. R. A. is'^ 42°^ ; Decl. 18° ss' N. Nova ; Double ; 9th and 11th magnitudes. Passy ; May 8, 1825 ; Seven-feet Equatorial. Position = i3*» 59' n/ 1 5 Obs. 1 Diff. = 1° 38' ) ^ _ , ,.^ , Distance = 35".i48 | 5 Obs. | Diff. = 2".o43 ] Extremely difficult. Observed on the meridian. Night fine, but the small star is very faint. Passy ; May 27, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position = 140 i' nf I 5 Obs. Diff. = 1° 40' ) e- * 1 a-o. u Distance= 34".66r | 5 Obs. Diff. =o".9i3 j ^""^'^"^^^V ^^^^cult. Mean Result. Position 14° o' nf-. Distance 35''.o54 ; Epoch 1825.37. 1 88 Mr. South's observations of the apparent distances No. DCLVI. R. A. IS** 42" ; Decl. 22° 12' N. Nova ; Double ; 7th and 8th magnitudes. Passy ; March 7, 1825 ; Seven-feet Equatorial. Position = 62° o^ sp Distance= i' 25".S99 5 Obs. 5 Obs. DifF. = DifF. = Observed when z^ 40' east of the meridian. Passy ; March 26, 1825 ; Seven-feet Equatorial. 7th and 8th magnitudes. Position r= 61° 41' * p I 5 Obs. I Diff. = 1° o' | tt„c«.oo^„ Distance= 1' z6".^bj \ 5 Obs. | DifF. = i".i3oi "^^^teady. Mean Result. Position 61° 50' sp (lo Obs.); Distance i' ^6".oss (lo Obs.); Epoch 1825.20. No. D CLVII. R. A. 1 s^ 46- ; * Decl. 7° 1 2' S. Nova ; Double; 8^ and 9th magnitudes: the small star bears a tolerable illumination. Passy ; May 5, 1825 ; Seven-feet Equatorial. Position = 39° 4' nf Distance = 2"'S^9 5 Obs. I Diff. = 3° 5' ) Rather difficult. 5 Obs. 1 Diff. =:o".48i 5 Difficult. Observed when on the meridian. Stars tolerably well defined, but unsteady, tried to use a higher power than 181, but could not do it advantageously. Passy ; May 10, 1825 ; Seven-feet Equatorial. 8 J and 9| magnitudes. Position = 37° 29' nf 1 5 Obs. I Diff. 2° 36' ) p.;-!;^,,,^ Distance = ^".928 | 5 Obs. | Diff. o".24o ] D^^cult. A magnifying power of 181 is insufficient to separate distinctly these stars from each other ; but under a higher power they become pale and ill defined. Passy ; June 21, 1825 ; Seven-feet Equatorial. 9th and 9^ magnitudes. Distance r= 2".639 ) 5 Obs. | Diff. = o".336. Very difficult. Observed when 50 minutes west of the meridian. Night fine. Mean Result. Position 38° 16' nf; Epoch 1825.35 ; Distance 9,". 699 ; Epoch 1825.39. and positions of ^^S double and triple stars, &c. 189 No. DCLVIII. R. A. 13^ 51*" ; Decl. 26° 41'N. Struve, 449 ; Hist. Gael. 335 ; Double ; 9th and 10th magnitudes ; small star decidedly blue. Blackman-street ; April 18, 1824 ; Five-feet Equatorial. Position = 29° 12' .^ I 5 Obs. Diff. = I* 9' \ Difficult. Distance z= 4 '737 | 5 Obs. Dirt. = o".632 ) Blackman-street ; April 19, 1824 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 28° 32' sp I 5 Obs. DifF. = 1** 13' ) p.-^^ ,. Distance = s"-29S \ 5 Obs. DilF. = o".889 j ^^"^cult. Mean Result. Position 28° 52' sp ; Distance 5".oi6 ; Epoch 1824.30. No. DCUX.* R. A. 13^ 56"" ; Decl. 17° 12' S. Struve, 451 ; Hist. Gael. 233 ; Double ; 9th and 11th, or 12th magnitudes. Passy ; June 1, 1825 ; Seven-feet Equatorial. Position = 70° 10' sf c Obs. [ DifF. r= i** 4' ) tj . , ,.«- ,^ Distance = 3^.625 5 Obs. | DiiF. = i".875 1 ^^"''^^"^^ ^^*^^^*- Observed when on the meridian, but small star very indistinct. Passy ; June 9, 1825 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position = 79° 44' sf Distance = 3i".577 5 Obs. I DifF. = 1° 28' I ,T- K4. f ui 5 Obs. I Diff. = o".937 1 ^'g^* ^*^^ favourable. Measures not excessively difficult. Stars steady. Passy; June 12, 1825; Seven-feet Equatorial. 9th and 12th magnitudes. Distance =3 1".889 | 5 Obs. J Diff. = i".o82. Excessively difficult. Mean Result. Position 19" ^i sf'. Epoch 1825.43 ; Distance 32*.o3i ; Epoch 1825.44. 190 Mr. South' s observations of the apparent distances No. D CLX. R. A. 14'* o' ; Decl. 22° s' N. Nova ; Double ; 8^ and 1 oth magnitudes : large, white ; small, blue. Passy ; May 5, 1825 ; Seven-feet Equatorial. Position = Sep 9' n/ 1 5 Obs. Diff. = 3° 35' > Difficult. Distance = 4 .741 | 5 Obs. Diff. = o".36o5 Very difficult. Observed when on the meridian ; the small star does not bear a good illumination. Passy ; May 10, 1825 ; Seven-feet Equatorial. 8f and 1 Oth magnitudes. Position = 70° 17'n/ 5 Obs. I Diff. = 3° 34' \ Very difficult Distance = 5".035 5 Obs. | Diff. = o".48 1]^^^ aimcuit. The small star is blue, and bears but the most feeble illumination. Mean Result. Position 69° 4S' nf'. Distance 4^.888 ; Epoch 1 825.35* No. DCLXI. R. A. 14^^ 1" ; Decl. 2'> 30' S. Nova ; Double ; 9th and 9^ magnitudes. Passy ; May 5, 1825 ; Seven-feet Equatorial. Position s 62° 23' »/] 5 Obs. I Diff. = i° 2' ) A hw minutes west Distance = 7".988 | 5 Obs. j Diff. =0". 3 84) of the meridian. Passy; May 9, 1825 ; Seven-feet Equatorial. 9| and 10th magnitudes. Position = 63° 20' nf\ 5 Obs. 1 Diff. = 1" 15' ) Difficult. Distances 7".886 | 5 Obs. j Diff. = o".4o83 Very difficult. Mean Result. Position 62° 51' nf'. Distance 7".937 ; Epoch 1825.35. Position 16® 48' sf \ 5 Obs. Distance i^'.^6 J 5 Obs. and positions 0/458 double and triple stars, &c\ 191 No. DCLXII. R. A. 14^ 3" ; Decl. 29° 35' N. Nova ; Double ; 8th and 12th magnitudes. Passy ; May 7, 1825 ; Seven-feet Equatorial. Position = 18° 1/ s/\ 5 Obs. I Diff. = 3,: ^' I Excessively difficult. Distances 13 '.349 | 5 Obs. J Diff. = i .2503 ' Observed on the meridian. Night fine; but the small star is extremely faint, and scarcely bears any illumination. Passy ; May 10, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Siff! = f'."o } Excessively difficult. Small star is blue, and allows only the most feeble illumination, Passy ; June 1, 1825 ; Seven-feet Equatorial. 8th and I2th magnitudes. Distance = i3".6o7 | 5 Obs. j Diff. = d'.()bz. Excessively difficult. Mean Result. Position 17° 32' sf\ Epoch 1825.35 ; Distance i3".8oi ; Epoch 1825.37. No. DCLXIII. R. A. 14'' 40" ; Decl. 23° 30' S. Nova; Double ; 8th and 10th magnitudes ; small, blue. Passy ; May 5, 1825 ; Seven-feet Equatorial. Position = 51° 14' « o 5 Obs. Diff. = 1° 28' ) j^.^. .. Distance= s6".624 5 Obs. Diff. = o".48i ] ^^^^^ult. Observed when 10 minutes east of the meridian. Passy ; May 9, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. Position = 50° 33' sp I 5 Obs. I Diff. = 0° 58' ) Difficult. Distance = 56^769 | 5 Obs. | Diff. = o".4oB 3 Very difficult. • Observed on the meridian ; but stars not steady. Mean Result. Position 50" 53' sp ; Distance 56".696; Epoch 1825.35. 192 Mr. South's observations oj the apparent distances No. DCLXIV. R. A. 14^ 53" ; Decl. 16° 29' N. Nova; Double ; 9th and 9^ magnitudes. Passy ; May 5, 1825 ; Seven-feet Equatorial, Position z= 84° 9' «p I 5 Obs. I DifF. =0° 58' ) „ .• r . Distance = 2j".7s6 5 Obs. | DifF. =o".8i7l ^^^^^^^'^^^^y* Measures easy j each star bears a tolerable illumination. Passy ; May 9, 1825 ; Seven-feet Equatorial. 9| and 10th magnitudes. Position = 83° ^6' sp 5 Obs. I DifF. = 1° 12' ) ^.a. ,. Distance = zs.'pip 5 Obs. | DifF. = o".432 ] ^^^^cult. Mean Result. Position 84° 9.' sp; Distance 25".837 ; Epoch 1825.35. No. DCLXV. R. A. 14^ 65"^ ; Decl. 17° 13' S. Nova ; Double ; Si- and 10th magnitudes. Passy ; April 3, 1825 ; Seven-feet Equatorial. Position = 2° g' sf\ 5 Obs. Distance = 24".7i5 j 5 Obs. DifF. = lO 15' ■) Difficult. Diff. = o".553 3 Very difficult. Passy ; May 10, 1825 ; Seven-feet Equatorial. 8| and II th magnitudes. 5 Obs. I Diff. = o« 35' ^ ,. ,.-e .^ 5 Obs. I Diff. = o".866l V^^y ^^^'^^^^^ Observed on the meridian. Night fine. Position = 1° 35' */ Distance = 25".428 Passy ; June 10, 1825 ; Seven-feet Equatorial. 8| and 10th magnitudes. Position = 1° 49' «/ 1 5 Obs. I Diff. = i° 9' ) Difficult. Distance = 25".^67 | 5 Obs. j Diff. = i".27o5 Very difficult. Observed on the meridian : the small star bears but a very feeble illumination. Mean Result. Position 1° 51' sf; Distance 25^270; Epoch 1825.35. and positions o/*458 double and triple stars, &c. 193 No. DCLXVI. R. A. 14*^ 56" ; Decl. 75** 36' N. 33 (Bode) Ursse Minoris ; South's Catalogue. Double ; 6th and 9th magnitudes. Blackman-street ; June 8, 1824 ; Five-feet Equatorial. Position = 52° 6' n/ I 5 Obs. I DifF. = 0° 19' ) Distance = 2' 53".259 | 5 Obs. | DifF. =: i".322 5 • • • » Passy; June 12, 1825; Seven-feet Equatorial. 6th and 9th magnitudes. Position = 52° o'nf 5 Obs. I Diff.= 0° 20' ) tt„.«..-j„ Distance = 2' 53".ioi 5 Obs. | Diff.= o".84i j ^""eaay. Mean Result. Position 52° 3' nf; Distance 2' 53". 180 ; Epoch 1824.94. No. DCLXVII. R. A. 15^ 3" ; Decl. 4° 55' S. Nova ; Double ; 9th and 1 3th magnitudes. Passy ; May 10, 1825 ; Seven-feet Equatorial. Position = 65® 30' rap I C Obs. 1 DiflF. = o° 42' ) -. . , ,.- . Distance = 3i".i75 I 5 Obs. | Diff. = i".i22} E^^ssively difficult. The small star bears only the slightest illumination ; and unless the weather is very favourable, it cannot be seen even in the unilluminated field of view of this instrument, with a power of i8i. Observed with 92. Passy ; June 9, 1825 ; Seven-feet Equatorial. 9th and 12th, or 13th magnitudes. ' Position = 65° 39' np I 5 Obs. | DifF. = 1° 45' 1 E^cefsivelv difficult Distance = 32". 188 | 5 Obs. | DifF. = o".84i § excessively dimcult. Night fine ; but the small star scarcely bears the least illumination. Observations made with 92. Mean Result. « Position 65° 39' np ; Distance si".i8i ; Epoch 1825.39. MDCCCXXVI. c c 194 Mr, South' s observations of the apparent distances No. DCLXVIII. R. A. 15^ 4" ; Decl. 39* 38' N. Nova ; Double ; 9th and isth, or 15th magnitudes. Passy; June 9, 1825 ; Seven-feet Equatorial. Position = 64° 56' np I 5 Obs. | DifF. = 2° 58' i p3,,„_i„_,„ difficult Distance = io".6 15 j 6 Obs. | DiflF. = i". 1 30 J ^excessively ditticult. Night remarkably fine ; yet the small star is so extremely obscure, that the results may be a little erroneous. Passy ; June 10, 1825 ; Seven-feet Equatorial. 9th and 15th magnitudes. Position = 59°!?' np I 5 Obs. I DifF. = 3° 55' ? r«„,„, •„„i„ j:^:^,,^. Distance = 56".866 ^ | 5 Ots. | DifF. = o".6oi \ Excessively difficult. The small star is light blue, and bears scarcely the least illumination ; the mea- sures must be regarded with suspicion. Passy ; June 12, 1825 ; Seven-feet Equatorial. 9th and 14th, or 15th magnitudes. Position = 63° ^' np I 5 Obs. Position = 63° 30' np \ 5 Obs. Diff = i° % \ Excessively difficult. The first set was gotten with a power of 92 ; the second with 157. The small star is light blue, and with 181, (the commonly used eye-piece,) it could scarcely be distinguished. Observed when on the meridian. Night very favourable. ^^^^^-<^^ Mean Result. • ^i^ov., ■. •: , . Position 63° 50'np ; Distance 10". 740; Epoch 1825.44. In taking the mean, the position observed on June lo, is excluded. and positions 0/4*58 double and triple stars y &c. 195 No. DCLXIX. R. A. i^'^ 5" ; Decl. 15° 5'N. Nova ; Double ; 10th and 13th, or 15th magnitudes. Passy; June 9, 1825 ; Seven-feet Equatorial. Position = 74° 30' nf Distance = 6". 297 7 0bs. Diff. = 6° 33' J Very doubtful. 5 Obs. Difr. = o .577) ^ These stars will bear neither illumination nor magnifying power. With 181 nothing could be obtained worth transcribing; and 157 was tried unsuccessfully. The observations were made with 92, the lowest power I have ; and were attended with such extreme difficulty, that I regard them as little else than approximations. The stars on the meridian when observed, and the night unusually fine. Passy ; June 10, 1825 ; Seven-feet Equatorial. lOth and 15th magnitudes. Position = 710 46' nf I 7 Obs. I DifF. = 3° 15' ] Rxcessivelv difficult Distance = s".8i7 | 5 Obs. | Diff. = o".6oi j Excessively ditticult. The stars are so extremely pale, that a higher power than 92 cannot be used : the results are very suspicious : I have no confidence in their accuracy. The night is remarkably favourable for difficult observations. Mean Result. Position 73° S'nf; Distance 6". 057 ; Epoch 1825.44. No. DCLXX. R. A. 15^ 10™; Decl. 2«28'N. 5 Serpentis ; Struve, 480 ; III. 106. Double ; 7th and 15th magnitudes. Passy ; June 9, 1825 ; Seven-feet Equatorial. Position =51° 17' nf 5 Obs. DifF. = 2° 3' ) Extremely difficult. Distance = io".68o 5 Obs. DifF. = o".72i J Excessively difficult. Observed when on the meridian with a power of 92; with 181 and 157 I could not see the small star, which bears so very feeble an illumination, that the accuracy of the results is perhaps a little questionable. 196 Mr, South' s observations of the apparent distances No. DCLXX. continued. Passy ; June 14, 1825 ; Seven-feet Equatorial. 6th and 15th, or 20th magnitudes. * Position = 49° 45' nf \ 2 Obs. | Diff. = 3° 29'. Excessively difficult. The small star will not bear the slightest illumination. No measures of distance can be procured, and these of position are little else than approximations. Passy; June 17, 1825 ; Seven-feet Equatorial. 6th and 1 5 th magnitudes. Position =: ^\° & nf\ 5 Obs. Distance = io".7i6 ] 5 Obs. DiiF. = 2*' 20' i „ . , ..«- 1, DifF — o" 601 4 Excessively difficult. Observed on the meridian. Night fine ; but the small star will bear only the most feeble illumination. Mean Result. Position 50° 57' «/; Distance io".698 ; Epoch 1825.45. Sir W. Herschel has no measures of this star. (H.) No. DCLXXI. R. A. 15*^ 18" ; Decl. 10° 20' S. Nova ; Double ; 9th and 11th magnitudes. Passy ; May 27, 1825 ; Seven-feet Equatorial. Position =: 43° 15' «/ 1 5 Obs. Distance r= 9".487 J 5 Obs. Diff. = 2° o' \ Extremely difficult. Diff. zz d'.gSz \ Excessively difficult. The small star will not bear a good illumination. Night fine. Passy; May 31, 1825 ; Seven-feet Equatorial. 9th and 13 th magnitudes. Position = 42° 14' sf\ 5 Obs. I Diff. = 2° 23' ) Excessively difficult. Distance = 9 .659 ( 4 Obs. | Diff. = o".9i3 ) ^ From the extreme faintness of the small star, great reliance must not be placed in the accuracy of these measures. Night tolerably good. Mean Result. Position 42° 44' sf\ Distance 9' .573 ; Epoch 1825.41. and positions of 4!58 double and triple stars, &c. 197 No. DCLXXII. R. A. 15^^ 22"" ; Decl. 19° 35' S. Nova ; Double ; 8th and 10th magnitudes. Passy ; May 9, 1825 ; Seven-feet Equatorial. Position = 13° sg'np 5 Obs. I DifF. = 0° 43' ) j^-ffi-^,. Distance = i i-'.ipp 5 Obs. | DifF. = o".432 5 ^-'"^cuit. The small star is decidedly light blue, and is rendered more distinct by slight illu- mination. Observed on the meridian. Passy ; May 10, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 12° 50' np I c Obs. I DiiF. = i°4':' ) xr j-a: 1^ Distance = ii".738 | 5 Obs. | Diff. = ,»ji, J Very difficult. Stars on the meridian when observed ; the smaller is blue, and bears but a feeble illumination. Night fine. Mean Result. Position IS** 14' np ; Distance ii".468 ; Epoch 1825,35. No. DCLXXIII. R. A. 15^ 23" ; Decl. 23' 52' S. Nova ; Double ; equal, each 8t magnitude. Passy ; May 7, 1825 ; Seven-feet Equatorial. Position = 27° 14'njo or */| 5 Obs. DifF. zz 1° 6' ^ Distance = 9". 1 66 ) 5 Obs. Diff. = d\^Si] • i 5 • Observed when a few minutes east of the meridian. Measures satisfactory. Night very favourable. Passy ; May 24, 1825 ; Seven-feet Equatorial. 8th and 8f magnitudes. Position = 27O 34' np I c Obs. I DifF. =.• i« 57' | t..«.„ ,^ Distance = p'.ipo ^ | 5 Obs. | DifF. = o".745l ^^^^"^*- Observed on the meridian, but night unfavourable. Mean Result. Position 27« 4,^' np or 5/; Distance 9".i78 ; Epoch 1825.37. 198 Mr. South* s observations of the apparent distances No. DCLXXIV. R. A. 15^ 32"^ ; Decl. se"" 54' N. Nova ; Double ; 8th and S^ magnitudes. Passy ; May 7, 1825 ; Seven-feet Equatorial. Position = 4° 55' sp I 5 Obs. DifF. = i° 20' ) g , . ,, , g , Distance = i5".855 j 5 Obs. DifF. = o".4o8 ] ^^^^"^^ ^"*^ ^^" delined. A few minutes west of the meridian when observed. Passy ; May 24, 1825 ; Seven-feet Equatorial. 8| and 8| magnitudes. Position = 5° 6' 50 I 5 Obs. DifF. = 0° 26' ) o,.- r,^.^„. Distance = J5".44i | 5 Obs. Diff. = o".3365 Satisfactory. Observed on the meridian. Stars tolerably steady. Mean Result. Position 5° o' sp\ Distance 15^.648 ; Epoch 1825.37. No. DCLXXV. R. A. 15^ 51' ; Decl. 22° 16' N. Nova; Triple ; A of the 9th, B of the 10th, and C of the 8th mag- nitudes. Measures of A B. Blackman-street ; July 8, 1824 ; Seven-feet Equatorial. Position = 62° 49' sp j 5 Obs. Distance = s"'35^ I 5 ^'^s. DifF. = 1° 15' 7 Very difficult. DifF. = o".432 3 Extremely difficult. The small star bears but the most feeble illumination. Observed when 45 minutes west of the meridian. Passy ; June 10, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 6oO 44' ^P 5 Obs. Diff. = 2° 32' 1 y ^^^^^^^ Distance = 4 .821 5 Obs. Diff. =0.529) ' Observed on the meridian. Night fine ; but neither star bears a good illumination. Mean Result. Position 61° 46' 5/); Distance 5".o86 ; Epoch 1824.98, and positions of 4; 58 double and triple stars, &c, 199 No. DCLXXV. continued. Measures of A C. Blackman-street ; June 8, 1824 ; Five-feet Equatorial. Position =33° 45' sp | 5 Obs. j Diff. = 1° 15'. Difficult. (C being to the south of A.) Observed on the meridian ;, but night very bad. Blackman-street ; July 8, 182 1 ; Seven-feet Equatorial. 9th and 8th magnitudes. = i' i".539 I s Obs. I Diff. = 2".09i 5 ^^^ aimcuir. (The star C being to the south of A.) Position rr Distance : Passy ; June 10, 1825 ; Seven-feet Equatorial. 9th and 8th magnitudes. Distance = i' i".527 | 5 Obs. [ Diff. =o".ygi. Very difficult. The proximity of the star B to A, and neither of them bearing a good illumina- tion, or a high magnifying power to separate them considerably from each other, render the observations of distance of the two stars A C difficult. (The star C is to the south of A.) Night pretty fine. Mean Result. Position ss*' 34' sp ; Epoch 1824.48 ; Distance 1' i".5S3 ; Epoch 1824.98. No. DCLXXVI. R. A. 15^ 54"^ ; Decl. 33° 52' N. p Coronse ; Struve, 503 ; VI. 93- Double ; 6th and 15th magnitudes ; small, blue. Passy; June 17, 1825 ; Seven-feet Equatorial. Position - 34° 34' sf\ 5 Obs. I Diff. = 0° 34' ^ _. . , .._ , Distance = 1' i8".799 I 5 Obs. | Diff. = o".962 \ Excessively difficult. Observed with 92 : with a higher power I could not distinguish the small star, even under the most feeble illumination. The night is fine ; but the measures are attended with such extreme difficulty, that those of distance are perhaps liable to a little inaccuracy. 200 Mr, South's observations of the apparent distances No. DCLXXVI. continued. Passy; June 19, 1825 ; Seven-feet Equatorial. 6th and 15th magnitudes. Position = 35° 14' */| 5 Obs. Distance=i'2o".22i | 5 Obs. Diff = o" fzA Excessively difficult. Observed on the meridian with 92 ; with a higher power the small star is not visible ; the measures of distance were obtained with the utmost difficulty, and are perhaps of a suspicious character. Passy ; June 21, 1825 ; Seven-feet Equatorial. 6th and 15th or 20th magnitudes. Position z= 35° 30' */ | 5 Obs. | DifF.=: 1° 1'. Excessively difficult. Observed with 92. Night tolerably good ; but I could not procure a single measure of distance. Passy ; June 29, 1825 ; Seven-feet Equatorial. 6th and 14th or 15th magnitudes. Distance = 1' i8".568 | 5 Obs. | DifF. = 2".o43. Excessively difficult. Observed with 92. Stars very steady, and 45 minutes west of the meridian. Mean Result. Position 35° 6' 5/; Distance 1' 19". 196; Epoch 1825.48. Sir W. Herschel states the position of this star on the 20th August 1783 at 54° 27' sf, and its distance at 1' 27". 73. This is indeed a surprising change in a star of the 6th class, and which can hardly be real. It is more than probable that a mistake of a revolution (22^ ) in the reading off of the micrometer took place in the earlier measure, which would conciliate the results within about 3°. Piazzi's catalogue assigns no proper motion to this star. (H.) and positions of 4° ; Decl. 32° 45' N. 23 Herculis; Struve, 518 ; V. 88. Double ; 7th and 11th magnitudes. Passy; June 17, 1825; Seven-feet Equatorial. Position = 69° 24' n/ f 5 Obs. Diff. = o° 30' "> ^ ^ , ,.«. ,^ Distance = i&'.glg ^ \ 5 Obs. Diff. = d'.sSZ \ ^""^'^"^^^y ^^^^"^^- The small star bears but a very feeble illumination. Passy; June 18, 1825; Seven-feet Equatorial. 7th and 11th magnitudes. Position = 69° s^'nf I 5 Obs. I DifF. = i' 12' j difficult Distance = 36".78o | 5 Obs. | Diff. = o".769 ] ^i^^cuit. Observed on the meridian j night fine ; but the small star does not bear a good illumination. Mean Result. Position 69"^ SS' nf; Distance 36".844; Epoch 1825.46. This cannot be the same star as that described by Sir W. Herschel as V. 88, whose angle of position is stated at 54° 6' spin 1783. (H.) san^ii-Mti via i. No. DCLXXIX. R. A. iG"" 32"" ; DecL 23° 23' N. Nova ; Double ; 8th and 9th magnitudes. Passy; May 27, 1825; Seven- feet Equatorial. Position = 1° 13' «/ Distances 16". 860 5 Obs. 5 Obs. Diff. = 0° 30' ) c ^- f * Passy ; June 12, 1825 ; Seven-feet Equatorial. 8| and 9th magnitudes. Position = qo 58' «/ I 5 Obs. I Diff. = 0° 55' ) <,. , Distance = i7".2o8 | 5 Obs. | Diff. = o".865 j ^'^eaay. Mean Result. Position i'' ^ sf; Distance i7".034; Epoch 1825.42. and positions 0/4,58 double and triple stars, &c, 203 No. DCLXXX. R. A. 16^ 35" ; Decl. 13** 58' N. Nova ; Double; 9th and 13th magnitudes. Passy ; June 9, 1825 ; Seven-feet Equatorial. Position = 65° 26' np I 5 Obs. | Diff. = i^ 14 { Excessively difficult. Distance z= 13 .535 | 5 Obs. [ Difr. := o'.^zg ) ' The night is very favourable, but the small star will not bear the slightest illumi- mination ; hence the results are liable to some inaccuracy. Passy; June 12,1825; Seven-feet Equatorial. 9th and 1 2th magnitudes. Position =65°46'n/> Distance = i4"-323 ^ - ■ I * ^ > Excessively difficult. 5 Obs. I Diff. = i".274^ Observed on the meridian. Night fine j but neither star bears much illumination. Mean Result, Position 6s° 36' np ; Distance is" -9^9 ; Epoch 1825.45. No. D CLXXXI. R. A. 16^ 38°^ ; Decl. 28° 42' N. 46 Herculis ; Struve, 532 ; I. 79. Double ; 7th and 1 2th magnitudes ; small star decidedly blue, and becomes much more distinct by slight illumination. Blackman-street ; April 28, 1824 ; Five-feet Equatorial. Position =73° 46' sf Distances: 4". 396 5 Obs. 5 Obs. Diff! = i".073 [ Extremely difficult. Observed when 3'* 10' east of the meridian ; the results must therefore not be deemed standard. Blackman-street ; June 29, 1824 ; Five-feet Equatorial. 7 th and 1 0th magnitudes. Position = 71° 8' */ | 5 Obs. Position = 70° 44' */ 1 5 Obs. The first series was observed when the stars were one hour east of the meridian, without artificial illumination; the last when they were 35 minutes distant firom it. During strong twilight the blue colour of the small star was very decided. Diff. = 3° o' 7 By twilight. Diff. = S° S^' i 2y lamp illumination. 204 Mr. South' s observations of the apparent distances No. DCLXXXI. continued. Blackman-street ; same date ; Seven-feet Equatorial. Position = 71° 12' sf\ s Obs. I DifF. = 1° 17' } Re^narkablv steadv Distance = 6".77o j 5 Obs. | DifF. = o".288 5 ^en^arKably steady. Observed when ten minutes east of the meridian. Blackmail-Street; July 3, 1824; Five-feet Equatorial. 7 th and 11th magnitudes. Position = Distance = 74° 43' sf I 5 Obs. I DifF. = 2° 20' ) ,. ..n- ,^ = 6'tiH n 5 Obs. I Diff. = o".632i ^"^ ^^^"''^'- Observed when the stars were a few minutes west of the meridian, but the night by no means favourable. Passy; March 20, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position =: 72° 3' «/ j 2 Obs. DifF. = 0° 15' ) Mons. Bouvard. Position 1= 71*49' sf \ 2 Obs. DifF. — 3^51' j South. Observed when three hours east of the meridian. Stars very unsteady ; measures of distance impracticable. Passy ; June 10, 1825 ; Seven-feet Equatorial. 8th and i4th or 15 th magnitudes. Position = 75° 46' sf | 5 Obs. [ DifF.= 2" 8'. Excessively difHcult. Observed on the meridian, but the small star is so extremely indistinct that no measures of distance can be procured j and the observations of position are very suspicious. Passy ; June 14, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. . Position = 749 i' 5/1 7 Obs. [ DifF. = 5° 2'. Extremely difficult. Stars on the meridian; the smaller is very indistinct. Measures taken with the greatest care ; but on account of the unsteadiness of the stars, they perhaps ought not to be considered standard. and positions 0/4,58 double and triple stars, &c» 205 No. DCLXXXI. continued. Passy ; June 18, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position = 73° 5 1' sf I 7 Obs. DifF. = 3° 47' 1 difficult Distance = 5".364 j 5 Obs. DifF. = o".2645 ^^"icuit. Observed on the meridian. Stars well defined, and tolerably steady. Passy ; June 29, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes ; small, light blue. Position = 74° 10' sf [ 7 Obs. DifF. = 1° 10' ) ^ difficult Distance = 4^79 1 J 5 Obs. DifF. = o".36o j ^°^ tli«icuit. Observed when 10 minutes west of the meridian. Evening very favourable ; stars remarkably steady, and well defined. The results highly satisfactory. Examined the large star with 41 3 and 512, but found it perfectly round j hence the discordances do not arise from any elongation of itt under the ordinary observing powers employed. Passy; June 30, 1825;. Seven-feet Equatorial. 8th and 12th magnitudes. Position = 77° i?'sf\7 Obs. I DifF. = 2° 7' 1 r):ffi-„i. Distance = 5". 193 | 5 Obs. | Diff. = 0^793 j ^i°icuit. Observed when 15 minutes west of the meridian. Stars faint, but very steady. Passy ; July 2, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position =75° 11'*/ Distance = 5". 103 7 Obs. 5 Obs. Diff! = o".6oi ] Excessively difficult. Observed when 10 minutes west of the meridian. Stars tolerably steady, but the small one is very faint. Mean Result. Position 7S° 51' sf(69 Observations); Epoch 1825.05. Distance 5".s9i {36 Observations); Epoch 1825.04. A single measure in 1783 gave 66° 36' sf for the position of this star, while another in 1802 gave 76° 18 . The present angle lies between them. This is a case, where from the 2o6 Mr. South's observations of the apparent distances No. DCLXXXI. continued. great inequality and closeness of the two stars, single mea- sures cannot be regarded as of any weight ; hence no certain conclusion can be drawn respecting its motion or rest. The distance however seems to have increased materially, as .5". 391 is much too great for a star of the first class ; and in 1783 the interval between the discs was stated at from 1 to i|^ diameter, according to the power used. This star should be watched: it is said to have a proper motion of o'^l4 per annum in R. A. (H.) No. DCLXXXII. R. A. iS'^ S9™ ; Decl. 30° 18' N. Nova; Quadruple ; A of the 9th, B of the 12th, C of 9|-, and D of the 15th magnitudes. Measures of A B. Passy ; June 9, 1825 ; Seven-feet Equatorial, Position = 59° 9' sf c Obs. I DifF. = i° 44' 7^ . , ,.«. , Distance = 4".8o9 5 Obs. | DifF. = o".986 jExcessively difficult. Night very fine, but the small star is extremely faint. Passy ; [June 12, 1825 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position = 60° 16' sf c Obs. DifF. = 2° 57' 7 ,, ^ , ..- . Distance = I4".7i3 5 Obs. DifF. = o".86s j Extremely difficult. Night favourable j but the small star is very indistinct. Measures of A C. Passy ; June 9, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 50° za! sf\s Obs. DifF. = 1° 18' \ ^r „ , Distance = i' ^'.^zi \ 5 Obs. Diff. = d'.^Sz ] ^"'^ ^ood. and positions of 458 double and triple stars, ^c 207 No. DCLXXXII. continued. Passy; June 12, 1825; Seven -feet Equatorial. 9tli and "9^ magnitudes. Position = 50^30' sf\ 5 Obs. Distance := 1' /^".ojb j 5 Obs. DifF. = DifF. ■ H o" 86c t Satisfactory. Measures of A D. Passy ; June 9, 1825 ; Seven-feet Equatorial. 9th and 15th magnitudes. Position zz 75° 30' nf; very suspicious ; (single measure.) Distance estimated 3 or 4 seconds nearer to A than is the star C ; but from extreme obscurity of D no measures can be obtained. Passy; June 12, 1825; Seven-feet Equatorial. 9th and J 5th, or 20th magnitudes. Position = 77° o' nf; very precarious ; (single measure.) No measure of distance practicable. Night fine. Mean Result. of AB. Position 59° 4^' 5/; Distance 14/'. 761; of AC. Position 50° 27' sf; Distance 1' 4^.299 ; of A D. Position 76° i5'nf±; estimated distance 1 minute; Epoch 1825.44. No. DCLXXXIII. R. A. 16^^ 42"^ ; Decl. 36° 15' N. Nova ; Double ; 9th and 10th magnitudes ; the small star does not bear a good illumination. Passy ; June 5, 1825 ; Seven-feet Equatorial. Diff! = o".384} Extremely difficult. Position =1 69** 19' nf\ 5 Obs. Distance = 7".249 j 5 Obs. Passy ; June 12, 1825 ; Seven-feet Equatorial. 9th and 1 0th magnitudes. Position =: 69*' 41' nf Distance =: 7".o67 5 Obs. *o* DifF. = o°57' 5 Obs. DifF. = o".288 5 ^^^ difficult. Small star is light blue, and bears only a very feeble illumination. Mean Result. Position 69° so' nf; Distance 7".i58 ; Epoch 1825.44. 2o8 Mr. South' s observations of the apparent distances No. DCLXXXIV. R. A. i?^ 3" ; Decl. 30° si N. Nova ; Double; 7th and 10th magnitudes. Passy ; June 16, 1825 ; Seven-feet Equatorial. Position = 88° 59' sf\ s Obs. | DifF. = i° 27' 7 ^ ^^ . Distance = z^'.S^z \ 5 Obs. | DifF. = o".505 5 ^^^^ dimcuit. The small star bears only a very feeble illumination. Passy ; June 19, 1825 ; Seven-feet Equatorial. 7th and 1 1th magnitudes. The small star is extremely faint. Mean Result. Position 89i<* lo' sf\ Distance 24".499 ; Epoch 1825.46. No. DCLXXXV. R. A. 17^ 6"» ; Decl. 26° 35' S. 38 Ophiuchi ; I. 35 ; South's Catalogue. Double; 8th and 12th, or 13th magnitudes. Passy; July 4, 1825 ; Seven-feet Equatorial. Position rr 61° 9' np Distance r= 6".249 7 Obs. I DifF. = 9° o' ) TT ^ A 5 Obs. I DifF. = o".962l Unsteady. The small star is so excessively indistinct, that the measures, especially those of distance, must only be regarded as approximations-. The star here observed is indisputably 38 Ophiuchi. I had re-measured 36 Ophiuchi for it in Blackman-street twice during the summer of last year ; not having found any other double star in the neighbourhood. On comparing however my observations with Sir W. Herschel's, it was evident thai we had not measured the same star ; and by close attention the small star of 38 Ophiuchi was perceived. My first attempts to determine the distance proving unsuccessful, cautious esti- mation regarded it as 5 or 6 seconds : the night however having somewhat improved, the above observations of it were and positions 0/4,58 double and triple stars , &c. 209 No. DCLXXXV. continued. procured. There is a small star* between 36 and 38, but which when examined with 413 and 512, 1 could not suspect to be double ; nor was the large star of 38 sub-divided by those powers. Passy ; July 13, 1825 ; Seven-feet Equatorial. 8th and 13th, or 15th magnitudes. Position rs 62° 12' np Distance = 7".7S$ 7 Obs. 5 Obs. Diff! = ©".360 j Excessively difficult. The small star is so extremely obscure, that the measures deserve but very little confidence. Observed on the meridian. Night favourable. Passy; July 14, 1825; Seven-feet Equatorial. 8th and 14th, or 15th magnitudes. Position = 60° S3'np\7 Obs. | Diff. = 3° S/ I Excessively difficult. Distance = 7 .359 | 5 Obs. | Diff. = o".6oi > ' Observed on the meridian with 157 : the small star so extremely faint, that with 181, the common observing power, I could not distinguish it. The accuracy of the results very questionable, Passy ; July 20, 1825 ; Seven-feet Equatorial. 8th and 13th, or 14th magnitudes. Position = S9° 5' ^P Distance = 7".i SS 7 Obs. 5 Obs. Diff! = ?".25o j Extremely unsteady. The measures are so excessively difficult, that I feel but little confidence in their accuracy. Mean Result. Position 60° 50' np('28 Obs.) ; Distance i'.isi ; Epoch 1825.53. If the star here measured be really the same with I. 35, its distance must be much increased. 7". 137 is a great distance, for a star even of the 2nd class. In 1783 it is described as having the interval of the discs only 1^ diameter of the large star, which, for a star of the 8th magnitude, could hardly correspond to more than 4" from centre to centre. The angles, it is true, agree — that given by Sir W. Herschel in 1783 being 60° 48' npy differing only 2' from its present value. This star requires further observation. (H.) • This star is 30 Scorpii, and it is the only star in the neighbourhood which is likely to be mistaken for 38 Ophiuchi. MDCCCxxvi. e e 210 Mr. South* s observations of the apparent distances No. DCLXXXVI. R. A. 17M1-; Decl. 28° 57' N. Nova ; Double ; 8th and 9th magnitudes. Passy ; June 16, 1825 ; Seven-feet Equatorial. Position = 85° 59' nf i 5 Obs. DifF. = o° 39' I Tolerably steady Distance = 55".! 17 I 5 Obs. ] Diff. = o".72i ] °^^^^°^y "^^°y* Passy ; June 19, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 85° 4' nf Distance r=: 5 4". 847 5 0!>- I P!ff- = °! 56', ^ Very difficult. 5 Obs. I Diff. = o".336 The small star is yery indistinct. Mean Result. Position 85° 31' nf; Distance 54".982 ; Epoch 1825.46. No. DCLXXXVII. R. A. 17MS" ; Decl. 24*^ 41' N, 70 Herculis ; Struve, 543. Double ; 5th and 9th magnitudes. Blackman-street ; July 10, 1824 ; Five-feet Equatorial. Position = 33° 30' nf\ 5 Obs. I Diff. = o° 30' \ t);^-,. Distance = 3' 37"433 I 5 Obs. I Diff = i".i68 ( ^^"^cult. The small star bears much less illumination, than its apparent magnitude would lead us to expect. The night is cloudy j but between the clouds the stars are yery brilliant. Passy ; June 23, 1825 ; Seven-feet Equatorial. 6th and 1 1 th magnitudes. Position = 33* 23' nf Distance = 3' 39".432 5 Obs. 2 Obs. Diff = o''.?68 } E^tre«^ely difficult. The small star becomes invisible under a yery feeble illumination ; the distance is very suspicious. Passy; July 14, 1825 ; Seven-feet Equatorial. 6th and lOth magnitudes. Distance = 3' 38".i5i | 5 Obs. \ Diff.= i".875. Very steady. Mean Result. Position 33° ^^ nf\ Epoch 1825.00 ; Distance 3' S^"'SS9 '■> Epoch 1825.18. and positions of 4<5S double and triple stars, &c. 211 No. DCLXXXVIII. R. A. 17^ 18- ; Decl. sf 8'N. Nova ; Double; 8th and 11th magnitudes. Passy ; June 18, 1825 ; Seven-feet Equatorial. Position = 76** 34' n/\ 5 Obs. Distance =: 33''.323 J 5 Obs. DiiF. = 1° 30' } „ ,._ , Diff. = o".4o8j^^^y'^'^^^^*- Passy ; July 2, 1825 ; Seven-feet Equatorial. 8th and 12th, or 13th magnitudes. Position = 75° 52' nf[ 5 Obs. I DifF. = 1° o' | <,. . Distance = 33".373 [ 5 Obs. | DifF. = 2".645 > ^^^ady. The small star is so extremely indistinct, that the measures are excessively difficult, and those of distance are open to suspicion. Mean Result. Position 76^ 15' nf; Distance 33".348; Epoch 1825.49. No. DCLXXXIX. R. A. 17^ 19"" ; Decl. 39' 25' N. Nova ; Double ; 8th and 8^ magnitudes. Passy; June 16, 1825 ; Seven »feet Equatorial. Position = 71° 52' «^ Distance = i' 29".oi8 5 Obs. 5 Obs. DifF. = 1° 32' Kt * * A DifF. = o".577| Not steady. Passy ; June 19, 1825 ; Seven-feet Equatorial. 8^ and 9th magnitudes. DifF. = 0° 27' > c* J Diff. = o".529r^^^^y- Mean Result. Position 71° 39' sp; Distance 1' 29^272 ; Epoch 1825.46. Position =71'' 26' sp I 5 Obs. Distances i' 29".526 | 5 Obs. 212 Mr, South' s observations of the apparent distances No. DCXC. R. A. 17' 23" ; Decl. sB"" 6' N. Nova; Double ; 8th and loth magnitudes. Passy ; June 9, 1825 ; Seven-feet Equatorial. Position = 40; 26; ./I s Obs. Diff. = lo ,5' } On the meridian. Distance = io".7it | 5 Obs. Diff. = o".264 j The small star is blue, and bears a tolerable illumination. Night unusually fine. Passy ; June 29, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 44" 14' sf \ 5 Obs. I DifF. = 2° 51' ) ^ ^, - .. Distance = 7.875 I 5 Obs. | DifF. = o".8i7 i ^" '^" °^""^^""' Stars remarkably steady ; the small one is decidedly light blue, and bears only a feeble illumination ; hence the measures are difficult. Passy ; July 2, 1825 ; Seven-feet Equatorial. 8th and 1 1th magnitudes. Position = 390 17'./ I s Obs. I DifF. = 1O42' 7 Excessively difficult Distance = io".820 [ 5 Obs. | DifF. = o".6oi \ Excessively ditticult. Small star decidedly pale blue, and bears but a very slight illumination. Stars steady, and 10 minutes west of the meridian. Passy; July 14, 1825; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 38»33'«/l c Obs. DifF. = 0^45' )„ ^ , .-a- ,^ . Distance = io".866 ^ \ 5 Obs. DifF. = o". Js^ \ Extremely difficult. The small star is light blue, and bears only a very feeble illumination ; night favourable; stars steady. Mean Result. Position 39^* 25' sf\ Distance io".799 ; Epoch 1825.49. The observations of June 29th are not included ; as how- ever the measures are of very considerable difficulty, I have not thought it advisable to suppress them. and positions of 4^8 double and triple stars, &c, 213 No. DCXCI. R. A. 17^ 32" ; Decl. 24** 30' N. Struve, 551 ; III. 104. Triple ; A 6th, B 10th, and C of the 9th magnitudes : the star B is decidedly blue, and bears a very considerable illumination. Blackman-street ; July 8, 1824 ; Seven-feet Equatorial. Measures of A B. Position = 81° 7' »/ 1 s Obs. DifF. = o° 3 1' ^ On the meridian Distance = if '.374. | 5 Obs. DifF. = o".3843 "" ^^® menoian. Passy ; June 23, 1825 ; Seven-feet Equatoiial. 7th and 10th magnitudes. Position = 80° 57' nf 5 Obs. I DifF. = 1° 18' > y unsteady Distance = i7".os4 5 Obs. j DifF. = 0^649 j ^^^^ unsteaay. Measures of A C. Blackman-street ; July 8, 1824 ; Seven- feet Equatorial. Position =71° 54' sf\ 5 Obs. DifF. = 0° 43' ) Distance = 2'38".o8i I 5 Obs. DifF. = 2".o9i j * * ' * Passy ; June 23, 1825 ; Seven-feet Equatorial. 7th and 9th magnitudes. Position = 71° 47' sf j 5 Obs. Distance = 2' 38''.454 j 5 Obs. SI = i''.986} Very unsteady. Mean Result. of A B. Position 81° 2' nf; Distance I7".2i4 ; Epoch 1825.00. of AC. Position 71° 50' sf; Distance 2' 28^.267 ; Epoch 1825.00. A very trifling change (-(- 2° 46') in position, and a rather more notable alteration (+2". 881) in distance, appear on comparing these observations w^ith those of 1783. (H.) 214 Mr. South's observations of the apparent distances No. DCXCII. R. A. 17^ sS'" ; Decl. 31° 14' N. Nova ; Double ; 9th and 10th magnitudes. Passy ; June 9, 1825 ; Seven-feet Equatorial. Position =65° ss' np 1 5 Obs. I DifF.= 1° 15' ) ^ . . ,. Distance = 5^ 1 76 | 5 Obs. | DifF. = o".eXg \ ^" *^^ meridian. The small star bears a tolerable illumination j yet the measures are difficult. Passy ; June 29, 1825 ; Seven-feet Equatorial. 9th and lUth, or llth magnitudes. Position = 66° 12' n » I c Obs. I DifF. = 3° 55' ) ^ ,, ... Distance = V'-SSj "^ | 5 Obs. I DifF. = o".697 \ ^^ *^^ meridian. Stars very steady, but the small one bears but a very feeble illumination : the measures are very difficult. Mean Result, Position 65° 33' np ; Distance 5".o29 ; Epoch 1825.47. No. DCXCIII. R. A. 17' 39" ; Decl. 27*^ 50' N. jtA Herculis ; Struve, 554 ; IV. 41 . Double ; 5th and 12th, or 13th magnitudes ; small, blue. Passy ; June 18, 1285 ; Seven-feet Equatorial. Dbs. Diff. = 0° 48' ) p . , ,.^ - 3bs. Diff. = o".625 1 Excessively difficult. The small star scarcely bears the slightest illumination. Position = 28° 49' «j9 Distance = 29".2i5 Passy ; July 1, 1825 ; Seven-feet Equatorial. 6th and llth magnitudes. Position = 29° 2i' sp Distance = 29".468 5 Obs. 5 Obs. Diff. = 0° 30' ) Very difficult. Diff. = i".202) Extremely difficult. The small star is decidedly blue, and bears but the most feeble illumination. Observed on the meridian ; stars very steady ; and I feel that the results merit considerable confidence. 'and positions of ^^S double and triple stars, &c. 215 . No. DCXCIII. continued. Passy ; July 13, 1 825 ; Seven-feet Equatorial. 5th and 13th, or 14th magnitudes. Position = 29° 33' sp I 5 Obs. I Diff. = 2° 30' ) y , Distance = 29".2o8 | 5 Obs. | DifF. = o".6oi 5 ^^"^^ ^^^^^y- The small star, which is blue, will bear scarcely the least illumination : the mea- sures are excessively difficult. Mean Result. Position 29° 14' sp ; Distance 29".297 ; Epoch 1825.50. From an imperfect observation in 1783, which made the position at that time 30° ±sp, it should seem that this star is liable to no material change of position. (H.) No. DCXCIV. R. A. 1 7*^ 43™ ; Decl. i° lo' N. 295 (Bode ) Ophiuchi ; South's Catalogue. Double ; 7th and 7^ magnitudes. Blackman-street ; June 26, 1824 ; Five-feet Equatorial. Position = 32° 2^ sp 1 c Obs. DifF. — . o" iz' J o ^- r Distance = i' 23".o7o | 5 Obs. Diff. = o'.S37i Satisfactory. Passy ; June 30, 1825 ; Seven-feet Equatorial. 7th and 7h magnitudes. Position = 32° 11' «j5 I 5 Obs. I Diff. = 1° 5' ") _, , Distances i' 22".293 | 5 Obs. | Diff. = o".553 j ^^^ ^"^^^^y' Observations very good. Mean Result. Position 32° 6f sp ; Distance i'22".68i.; Epoch 18:^5.00. 21 6 Mr. South* s observations of the apparent distances No. DCXCV. R. A. 17^ 43™ ; Decl. 25° 19' N. Nova ; Double; 8th and 10th magnitudes. Passy ; June 9, 1825 ; Seven-feet Equatorial. Position =53° 26' sf Distance = 6".6o^ The small star is light blue, and does not bear a good illumination. Night very favourable. Passy ; June 29, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 56° 24' «/j 5 Obs. Distances 6".93i j 5 Obs. DilsoV^s}^^'^^^®'^"^^- Observed when 5 minutes west of the meridian : stars very steady ; the small one decidedly light blue, and bears only a very feeble illumination. Passy ; July 19, 1825 ; Seven-feet Equatorial. 8th and 1 1th magnitudes. Position = 53° 39' sf\ 5 Obs. [ Diff. = 1° 25'. Extremely difficult. Stars a few minutes east of the meridian, and very unsteady ; the small one de- cidedly light blue, and bears no illumination: measures of distance impracticable. Night very clear. Mean Result. Position 54° 3o' sf; Epoch 1825.50 ; Distance 6". 768 ; Epoch 1825.47. No. DCXCVI. R. A. 17^ 51"' ; Decl. 6° 51' S. Nova ; Double ; 9th and 11th magnitudes ; small, blue. Passy ; June 9, 1825 ; Seven-feet Equatorial. Position = 78° 20' w» 5 Obs. I DifF.= i° 13') ^ ,, ... Distance = 8".288 5 Obs. | DifF.= o".673) ^^ '^^ "^^"^^^"- The small star bears but a very feeble illumination. The night is remarkably fine, but the measures are very difficult. Passy ; July 4, 1825 ; Seven-feet Equatorial. 9th and 11th, or 12th magnitudes. Position = 77° ii'np j 5 Obs. Distance = 8".5o4 | 5 Obs. The small star is decidedly pale blue, and bears but a very feeble illumination : the measures are extremely difficult. Mean Result. Position 77° 45' np ; Distance S".s96 ; Epoch 1825.47. DifF. - 1° co' ) ^ ,, ... and positions of 4}6^ double and triple stars ^ &c, 217 No. DCXCVII. R. A. 17^54" ; Decl. 26° 33' N. Struve, 560 ; II. 90. Double ; 8^ and 12th magnitudes ; small, decidedly light blue. Passy ; July 16, 1825 ; Seven-feet Equatorial. Position = 71; 44'./ 5 0bs. Diff. = i° 53' I Excessively difficult Distance = 7". ^61 5 Obs. DifF. = o".so5 S ^^^^^^^^^^y «i™cuif. Observed on the meridian. Night favourable ; but the small star bears hardly any illumination. The results are somewhat suspicious. Passy ; July 18, 1825 ; Seven-feet Equatorial. 8J and 11th, or 12th magnitudes. Position =710 48' */ 1 5 Obs. I DifF. = 1° 49' ) „ . , .-n. ,^ Distance = 7".545 | 5 Obs. | Diff. = o".li6 J Excessively difficult. Mean Result. Position 71° 46^5/; Distance 7*. 503 ; Epoch 1825.54. There is considerable discordance among the measures of this star at different epochs — that of 17S3 making the posi- tion 75° 9' sf, and that of 1802 77° 54' sf. On the whole, there seems ground to believe in a slow motion of about ^-th of a degree per annum in the direction np sf or retrograde ( — o°.i67), while the distance has probably not undergone any sensible change. Future observations must decide the point. (H.) No. DCXCVIII. R. A. 17^ 54" ; Decl. 22*' 30' S. Nova ; Double ; 8th and 9^ magnitudes. Passy ; June 30, 1^25 ; Seven-feet Equatorial. Position = 47° 22' np Distance= 30". 228 5 0bs.|Diff. = i0 4V|Diffi,^l,. 5 Obs. I DifF. = o".84i Observed when 10 minutes west of the meridian; stars very steady; but the small one does not bear a good illumination. MDCCCXXVI. // 2i8 Mr. South's observations of the apparent distances No. DCXCVIII. continued. N Passy ; July 4, 1825 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position = 47° 33' «;> I 5 Obs. 1 DifF. = i° 5' } Rxtremelv difficult. Distance = 3 i".o^6 \ 5 Obs. | DifF. = o ".889 ] ^^^remeiy aimcuit. The small star is blue, ^d bears scarcely any illumination : the observations of distance very suspicious. Several stars in the field. Passy ; July 10, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Distance = 3i".442 | 5 Obs. | Diff. = o".84i. Very steady. Measures excessively difficult ; and I have so little confidence in them, that should they favour one set already taken, more than the other, they should not be employed to the exclusion of either. The small star is light blue, and becomes invisible under a very feeble illumination. Mean Result, Position 47** ^i np \ Distance so". 9^2 ; Epoch 1825.51. No. DCXCIX. R. A. 17*^ 56° ; Decl. 25° 23' N. Nova ; Double; 8th and 11th magnitudes; small, light blue, and bears scarcely any illumination. Passy ; July 19, 1825 ; Seven-feet Equatorial. Position = 53° 43' «;> Distance = i8".648 5 Obs. I DifF. = 2° 42' ) Excessivelv difficult 5 Obs. I DiflF. = o".432 ) excessively aimcuit. Passy ; July 20, 1825 ; Seven-feet Equatorial. 8th and 1 Itli magnitudes. Position = 52° 51' sp Distance = 18". 840 5 Obs. 5 Obs. Diff! = o".S29) Extremely difficult. Stars very unsteady j the small one is blue. Mean Result. Position BS"" Til' sp ; Distance 18''. 744; Epoch 1825.55. and positions 0/4,58 double and triple stars, &c. 219 No. DCC. R. A. 18»» 6" ; Decl. 16° 43' S. Nova; Double ; 9th and 9^ magnitudes. Passy ; July 10, 1825 ; Seven-feet Equatorial. Position = 840 47' np I 5 Obs. DifF. = ,° 21' ) y . Distance = zg'^iSy \ 5 Obs. Diff. = ©".Si;) ^^^ steaay. Passy; July 13, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Diff. = 1° 12' Position := 84° 30' np Distance =: 28". 751 5 Obs. 5 Obs. Diff. = i".o34}^^^^*^"^*- Observed on the meridian : small star bears only the most feeble illumination. Night good. Mean Result. Position 84° SS' np ; Distance 28".969 ; Epoch 1825.53. No. DCCI. R. A. 18^ 15"° ; Decl. 6° 41' S. Struve, 574 ; Hist. C^el. 474. Double ; 7th and 10th magnitudes. Blackman-street ; June 26, 1824 ; Five-feet Equatorial. Position •= 73° 17' «o c Obs. Diff. = 2° ic' 7 ^ ^ , ..~ . Distance =6".68o "^ 5 Obs. Diff. = 0-284 j ^^^^^^^^^^ d^^^^^^^' The small star bears only the most feeble illumination. Passy ; June 30, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position = 70° is' spl s Obs. j Diff. = i» 1 1' 7 ,, ^ ^ j-az 1. Distance = 6".842 | 5 Obs. | Diff. = o".48 1 j Extremely difficult. Observed on the meridian : stars very steady ; the small one, which is very decidedly light blue, bears but the slightest illumination. Passy ; July 13, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position = 69° 29' sp \ 5 Obs. | Diff. = 1° 28'. Very difficult. Observed on the meridian. Night favourable. Mean Result, Position 71*" o' sp; Epoch 1825.11 ; Distance 6^761 ; Epoch 1824.97. 220 Mr. South's observations of the apparent distances No. DCCII. R. A. 18^ 20'" ; Decl. 19° 13' N. Nova ; Double ; 8th and 8 -J magnitudes. Passy ; June 9, 1 825 ; Seven-feet Equatorial. Position = 77° 24' sp I s Obs. I DifF. = 2° 8' } ^ . Distance = 6".402 | 5 Obs. | DifF. = o".3i2 ] ^^^^"X* A star of the 15 th magnitude precedes to the north at an angle of 9 or 10 de- grees, and distant from the larger of these stars perhaps 40 seconds : its obscurity renders measures of it impracticable. Passy ; June 30, 1825 ; Seven-feet Equatorial. 8| and 9th magnitudes. Position = 76° 19' nf\ 5 Obs. Diff. = 2» 14' ) ^ , Distance = 6". 174 | 5 Obs. DifF. = o".36o ] ^^^ ^^^^"^y* Observed on the meridian : measures very satisfactory. Mean Result. Position 76° 51' sp or w/; Distance 6".288 ; Epoch i825.47» No. D CCIII. R. A. i8»^ 25" ; Decl. 32° 8' N. Nova ; Double ; 9th and 10 j, or 11th magnitudes. Passy ; June 9, 1825 ; Seven-feet Equatorial. Position = 66° 23' tip I 5 Obs. DifF. = 1° 44' \ ^ _ difficult Distance = 6".533 | 5 Obs. DifF. = 0^384 5 ^^"^ dithcult. The night is extremely favourable, but the small star bears scarcely any illumination. Passy ; July 13, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 65° 55' sp 5 Obs. 1 Diff. = 1° 9' } y . Distance = 6".333 5 Obs. | Diff. = o".36o j ^^'^ ^^^^^J"' The small star is blue, and bears a tolerable illumination. Mean Result. Position 66^ 9' sp; Distance 6''.43S ; Epoch 1825.48. and positions oj 458 double and triple stars, &c. 221 No. DCCIV. R. A. i8»^ 32™ ; Decl. 9° 33' N. Struve, 582 ; Hist. Gael. 87- Double ; 9th and loth magnitudes ; both bluish, and bear a tolerable illumination. Blackman-street ; July 12, 1824 ; Five-feet Equatorial. Position = 0° 38' * w I c Obs. I Diff. = o" 34") ^^-n; 1^ Distance = 57".545 | 5 Obs. ; DiiF. = i" .6j^\^'^^''^^' Passy ; July 4, 1825 ; Seven -feet Equatorial. 9th and Qi magnitudes. Position = 1° 15' 50 1 c Obs. I DifF. = 0° 50' 7 ,. .-n: ,. Distance = 56".458 | 5 Obs. | DifF. = d'.Ls \ Very difficult. Stars very steady, but the small one does not bear a good illumination. Passy ; July 19, 1825 ; Seven-feet Equatorial. 9th and 9f, or 10th magnitudes. Position = 1° 19' sp 5 Obs. I DifF. = 0° 34' ) „ ^, ,.^ . Distance = sfW 5 Obs. j DifF. = d'.glj \ ^^^^^' ^^^^"l*' Set the position wire to zero, and the small star remained above the wire, whilst the large one continued bisected by it, during their passage across the field. Mean Result. Position 1° 4' sp (15 Obs.); Epoch 1825.20 ; Distance 5'i".65^ (10 Obs.) ; Epoch 1825.04. The observations of distance taken July 4, are rejected in taking the mean. No. DCCV. R. A. 18^ 59"^ ; Decl. 34° 22' N. Nova ; Double ; large, white ; small, light blue decidedly ; 8^ and 11th magnitudes. Passy; June 29, 1825; Seven-feet Equatorial. Position = 68° 22' sf\ c Obs. I DifF. = 2° 12' ) „ ^ ., Distance = 4".374 | 5 Obs. | DifF. = o".649 J ^^^7 steady. Small star bears but a very feeble illumination, and the measures are extremely difficult. 222 Mr. South' s observations of the apparent distances No. DCCV. continued. '^T . Passy ; July 12, 1825 ; Seven-feet Equatorial. 8f and 10th, or 11th magnitudes. Position = 68° 3' ,/ 5 Obs. Diff. = 2'> 10' ) ^^^^^^^1 ^^^^^ Distance = 4'.6 1 1 5 Obs. Diff. = 0.6015 ' The small star is light blue, and bears but a feeble illumination. Night fevour- able. Measures very difficult. Mean Result. Position es"* 12' sf; Distance 4" 492 ; Epoch 1825.51. No. DCCVI. R. A. 18^ 42" ; Decl. 32° 37' N. - V Lyras ; Struve, 591 ; V. 40. Double ; 6th and 15th magnitudes. Passy ; August 10, 1825 ; Seven-feet Equatorial. Posidon = 34: H' 'f 5 Obs. 1 Diff. = .» 38' > Excessively difficult. Distance = 59 .933 ± 3 Obs. | Diir. = I'^.oSz) ^ Stars very steady, but the small one will bear no illumination. Observed on the meridian; the distance, I fear, may be liable to an error of two or three seconds. Night fine. Passy; August 16, 1825 ; Seven-feet Equatorial. 6th and 15th magnitudes. Position = 33° 32' sf 5 Obs. I Diff. = 0° 52' ) Excessively difficult Distance = 59".748 3 Obs. | Diff. = i".202 ] ^^^essiveiy airacuir. Observed on the meridian. Night very favourable. Mean Result. Position 33° 58' 5/(10 Obs.); Distance 59^840 (6 Obs.); Epoch 1825.61. There appears to have taken place a change of no less than + 5° 21' in the angle of position of this star since 1782, which for a star of the 5th class is considerable ; unless indeed from the extreme minuteness of the small star, errors of observation to a larger amount than usual be supposed. (H.) and positions 0/4,58 double and triple stars ^ (^c, 223. No. DCCVII. R. A. IS** 51"; Decl. 13° 23' N. 11 Aquilae ; Struve, 598 ; III. 32. Double; 7th and 11th magnitudes; small, decidedly blue. Blackman-street ; July 11, 1824 ; Five-feet Equatorial. Position = 28° 10' sp I c Obs. I DifF. = 2*^ i' ) ^ ^ , ,.n:. u Distance = ig'^sSz ^ \ 5 Obs. | Diff. = i".i36 j Extremely difficult. North following this, is a double star of the 4th class ; but its stars are so ex- tremely faint> that it is not measurable with this instrument. Passy ; July 4, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position = 30° 38' sp s Obs. I DifF. = 1° 4' ) Excessively difficult Distance = i9".934 5 Obs. | DiiF. = o".5S3 1 excessively oimcult.. The small star scarcely bears the least illumination. Observed on the meridian. Passy ; July 19, 1825 ; Seven-feet Equatorial. 6th and I2ih, or 13th magnitudes. Position = 29° 35' sp \ 5 Obs. j DifF. = 2° 51'. Extremely difficult. ' The small star is bluish, and becomes more distinct by a very slight illumination ; yet it is so faint, that I can obtain no observations of distance. Night extremely clear, and stars on the meridian. Mean Result. Position 29° 28' sp (15 Obs.) ; Epoch 1825.20; Distance 19".658 ; Epoch 1825.02. The measure of Sir W. H. in 1802 makes the angle of position of this star 31' 34' sp, being only 2° & different from the present. (H.) 224 Mr. South's observations of the apparent distances No. DCCVIII. R. A. 18^ 52" ; Decl. 14° 41' N. Struve, 599 ; n. 93. Double ; 8th and 12th magnitudes ; small, light blue. Passy ; July 24, 1825 : Seven-feet Equatorial. Position = 1 5» 54' «P I 5 Obs. | Diff. = 3° 44' \ Excessively difficult. Distance = 6".i33 j 5 Obs. | DifF. = o".673 5 ' The small star is so extremely faint, and bears so feeble an illumination, that a little inaccuracy of the results may be suspected. Observed when on the meridian : stars very steady. Night remarkably favourable. Passy ; July 25, 1825 ; Seven-feet Equatorial. 8th and 12th, or 13th magnitudes. Position = 19° 29' n J? I 5 Obs. | Diff. = 6« 55'. Excessively difficult. The small star is only visible by glimpses, and then is so extremely indistinct, that to procure measures of distance is impossible. Passy ; July 27, 1825 ; Seven-feet Equatorial. * 8th and 12th magnitudes Position r: Distance = 20° 20' np I 5 Obs. I Diff. = 4° 10' 7 ^j . , ..«. ,, = 7". X5S I 5 Obs. I Diff rz J".36o \ Excessively difficult. The small star is pale blue, and is so very obscure, that the measures are exceed- ingly precarious. Night fine. Passy ; July 28, 1825 ; Seven-feet Equatorial. 8| and 1 2th magnitudes. Position = 17° 32' n;> I 5 Obs. Diff. = 3° 42' ) Kxcessivelv difficult Distance = 6".744 | 5 Obs. Diff. = o".649 j Excessively dithcult. The night being very favourable and the stars steady, I applied a power of 157 to procure these observations : little or no advantage however was derived from the change : the measures are so extremely difficult, that I have no confidence in the accuracy of this, or of any individual series ; the mean however of all, is probably not very remote from the truth. and positions of ^58 double and triple stars ^ &c. 225 No. DCCVIII. continued. Mean Result. Position 18° 19' np (20 Obs) ; Distance 6". 677 (15 Obs.) ; Epoch 1825.57. In 1783 the position was 16° o' np, and in 1802 16*46' npy so that this star has undergone no change. The distance too is nearly as it was. (H.) No. DCCIX. R. A. 18^ 52™ ; Decl. 36° ii'N. Struve, 600 ; I. 58. Double ; 8th and 12th magnitudes ; small, pale blue. Passy ; July 24, 1825 ; Seven-feet Equatorial. Position = 20° 2' np Distances 5 ".556 5' SL': I dIe^^-;^:; I Excessively difficult. 5 This star so much resembles the last measured double star (No. 708), that on ob- serving it in the field of the telescope, I thought I had perhaps neglected to alter the direction of the instrument. The small star bears but the most feeble ilhimina- tion ; and although the night is in every respect favourable for delicate observa- tions, still the results must be regarded with some distrust. Passy; July 27, 1825; Seven-feet Equatorial. 8th and 11 th, or 1 2th magnitudes. Position z= 20° 41' np [ 5 Obs. Distance r: 5".400 J 5 Obs. DifF. = o".igz\ Excessively difficult. Observed when 15 minutes east of the meridian. Night very fine; but the small star will not bear any illumination. Measures of precarious accuracy. Mea?i Result. Position 20° 21' 71 p ; Distance 5^.478 ; Epoch 1825.57. In 1783 (1783.21) the angle of position was 13" o' np. Thus in 42.36 years + 7^ 21' have been described, being at the rate of + o°.i73 per annum. (H.) MDCCCXXVI. gg 226 Mr. South' s observations of the apparent distances No. DCCX. R. A. 18^ 57" ; Decl. i6° ss' S. Nova ; Double ; 6th and loth magnitudes; small, light blue. Passy ; July 13, 1825 ; Seven-feet Equatorial. Position = 85° 18' «/ i 5 Obs. DifF. = i° 5/ ) y difficult. Distance = 7".o88 | 5 Obs. DifF. = o".673 ] ^^^ aimcuir. Observed on the meridian. Night very favourable; but the small star bears only the most feeble illumination. Passy ; July 15, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position = 85; ^^'nf\s Obs. Diff. = 2° 40' ) E^^^emely difficult. Distance = 7 '.021 | 5 Obs. DifF. = o' .3845 ^ Observed on the meridian. Stars very unsteady : the small one is light blue, and bears but a very slight illumination. Mean Result. Position 85° 25' nf; Distance 7".o54 ; Epoch 1825.54. No. D CCXI. R. A. iS^* 57™ ; Decl. 27° 4' S. Nova ; Double ; 8th and 10th, or 11th magnitudes ; small, blue. Passy ; July 13, 1825 ; Seven-feet Equatorial. Position = 35: 38' sf I 5 Obs. I Diff. = 1° / 1 y ^jg^^^i^^ Distance := 44 .375 j 5 Obs. | Diff. = i",i545 ^ Observed when lo minutes east of the meridian. Night very favourable, but the small star does not bear a good illumination. Passy ; July 15, 1825 ; Seven-feet Equatorial. 8th and l£th magnitudes. S:;t"=l fs'^^/^l I ObL- 1 Si = ;.li;| Excessive!, difficult. Stars tolerably steady ; but the small one will bear only the most feeble illumination. Night favourable. and positions of ^s^ double and triple stars, &c. 227 No. DCCXI. continued. Passy ; July 1 9, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Distance = ^^'.g^z \ 5 Obs. j Diff. = o'^Sg-j, Excessively difficult. Observed with 157: the small star became uivisible when 181 was employed. Night fine ; but measures very suspicious, and must not be received to the exclusion of either set previously taken. Mean Result, Position 34° 32' sf (10 Obs.); Epoch 1825.5s ; Distance 45". 108 (15 Obs.); Epoch 1825.54. No. DCCXII. R. A. 18^ 58" ; Decl. 35° 32' N. Struve, 605 ; I. 59' Double ; 9 J and 9^ magnitudes ; both white. Passy ; July 28, 1825 ; Seven-feet Equatorial. Diff. = 2° 29' ) ,r ^ J Diff. = o".288l^^^^^^^^y' Position = 77° 51' *p I 6 Obs. Distance =: 2".57o j 5 Obs. Observed when half an hour east of the meridian ; measures not difficult ; the stars bear a very tolerable illumination. Passy ; July 29, 1825 ; Seven-feet Equatorial. 9f and 10th magnitudes. Position = 77° 20' sp Distance = 2".782 6 Obs. I Diff. = 6° 7' ) r>;ffir„Ti- SObs. |Diff. = o".288l^^*^"^*• Observed on the meridian ; stars neither steady nor neatly defined ; the smaller is faint, but of the same colour as the larger. Passy ; July 31, 1825 ; Seven-feet Equatorial. 9? and 9f magnitudes. Position = 7f^i'sp III Obs. I Diff. = 4° o' | ^^^^^^ ^-g^^^^^^ Distances 2' .739 | 5 Obs. J Diff. = o'.336 j Stars on the meridian and tolerably steady ; but the smaller one is indistinct. 228 Mr. South' s observations of the apparent distances No. DCCXII. continued. Passy ; August 1, 1825 ; Seven-feet Equatorial. 9^ and 9|: magnitudes. Position = 76** 19' 5jB I II Obs. Distance =: 2".7 10 J 5 Obs. Siff: = o''.t88} Tolerably easy. Observed on the meridian ; stars steady, and well defined. Mean Result. Position 76^ 34' sp (34 Obs.) ; Distance 2".7oo (20 Obs.) ; Epoch 1825.58. In 1783 the position was 75"* o' sp, the interval of the discs 1 diameter. No change therefore has happened to this star. (H.) No. DCCXIII. R. A. i8»» 69"^ ; Decl. 75° 33' N. 233 (Bode) Draconis; Struve, 606; Hist. Gael. 360. Double ; 7^ and 8th magnitudes. Blackman-street ; June 26, 1824 ; Five-feet Equatorial. Position = 520 S9'^P \ 5 Ohs. I DifF. = 1° 36' ) u_,.„ , Distance = 6".^gg \ 5 Obs. | DifF. = o".sZ7 ] ^"^^^^^y- Passy ; July 14, 1825 ; Seven -feet Equatorial. 7i and 8th magnitudes. Position = 50° 2g'sp\s Obs. I DifF. = o° 51' ) ^ , Distance = 6".494 | 5 Obs. | DiiF. = o".384 J ^^^ ^^^^^J"' Passy ; July 16, 1825 ; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 53" 21' sp I 5 Obs. I DifF. = 1° 35'') „ . Distance = 6".3S4 | 5 Obs. | DifF. = d'.b/i^s] ^^^^^-V' The small star occasionally very faint. Mean Result. Position 52° 16' sp (15 Obs.) ; Distance 6^.549 (i5 Obs.) ; Epoch 1825.18. ajid positions of 4>5S double and triple stars, &c. 229 No. DCCXIV. R. A. 19^ 2™ ; Decl. 34° 28' N. Nova; Double ; 8^ and 10th magnitudes. Passy ; June 9, 1825 ; Seven-feet Equatorial. Position =: 1° 39'no 1 c Obs. DifF. =0° i?' ) ,r .-^ , Distance = I2".86i | 5 Obs. DifF. = o".673 j "^ difficult. After the measures were concluded, the position wire was placed at zero, and the small star was decidedly in the north preceding quadrant. Passy; June 29, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position =1° S9' np 5 Obs. Diff. = !<> 2' ) ,r j./e , Distance = 1 s".26s 5 Obs. DifF. = o".5os J ^^^ difficult. The small star is decidedly light blue, and does not bear a good illumination. Mean Result. Position 1° 49' np ; Distance is".o63 ; Epoch 1825.47. No. D CCXV. R. A. i9'» 8'" ; Decl. 16° 15' S. Nova; Double ; 8th and S^ magnitudes. Passy ; July 14, 1825 ; Seven-feet Equatorial. Position = 740 42' nf\ 5 Obs. I DifF. = 0° 58' | ,, Distance = 8".932 | 5 Obs. | DifF. = o".4s6 ] ^^"^ ^^^^^y- Observed on the meridian. About 39 seconds to the north of this star, and following it about 26 seconds 6f time, will be found another double star. Passy; July 15, 1825 ; Seven-feet Equatorial. 8^ and 9th magnitudes. Position = 740 1 1' n/ j 5 Obs. I DifF. = 0° 33' ) ^, Distance = 9".4oi ( 5 obs. | Diff. = o".505 ) Unsteady. 230 Mr, South' s observations of the apparent distances No. DCCXV. continued. Passy ; August 12, 1825 ; Seven-feet Equatorial. 8| and 9th magnitudes. Position = 74° 47' nf Distance zz. 9''-i9S 5 Obs. 1 Diff. ~ 0° 54' ) ,T .^^„A 5 Obs. 1 DifF. = o".84i \ Unsteady. Mean Result. Position 74"* SS' ^f(i5 Obs.); Distance 9".i76 (15 Obs.); Epoch 1825.56, No. DCCXVI. R. A. 19' 8- ; Decl. i6« 14' S. Nova ; Double ; 10th and lOj magnitudes; it is the star alluded to, in the observations of No. D CCX V. Passy ; July 14, 1825 ; Seven-feet Equatorial. Position r= 69° 40' *p I S Obs. I DifF. = 1" 35' ) „ . , ..a-^ ,^ Distance = 6^153 I 5 Obs. | DifF. = o".7li } Excessively difficult. These are pale blue stars, and do not bear any illumination. Observed when 25 minutes west of the meridian, and the measures are of doubtful accuracy. Passy ; July 19, 1825 ; Seven-feet Equatorial. lOth and lOi magnitudes. Position 71° 40' sp I 5 Obs. DifF. = 2° 15' ) ^ . . ,._ . Distance 6".4i9 | 5 Obs. [ DifF. = o".432 ] Excessively difficult. These stars are of a pale blue colour, and scarcely bear the least illumination. Observed when 10 minutes west of the meridian. Passy ; August 12, 1825 ; Seven-feet Equatorial. 10th and 10| magnitudes. Position = 71° 3' sp\ s Obs. | Diff. = 2° 10'. Excessively difficult. These stars are pale blue, and bear but the most feeble illumination. Observed on the meridian. Mean Result, Position 70° 5'i.' sp {15 Obs.) ; Epoch 1825.56 ; Distance 6".286 (10 Obs.) ; Epoch 1825.54. and positions of 4,^8 double and triple stars, &c, 231 No. DCCXVII. R. A. 19^ 11" ; Decl. 12* 1' N. 28 Aquilse ; Struve, 618 ; V. 34- Double; 6th and 12th magnitudes; small, decidedly blue, and bears a tolerably good illumination. Blackman-street ;* July 11, 1824 ; Five-feet Equatorial. Position = 84° 31' 5/ Distance r: sg".^22 5 Obs. S Obs. )iff. rr 2° II' I )ifF. =:o".758 5 Passy; July 20, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. 5 Obs. Position = 85O 41' */ Distance = 59". 139 5 Obs. DifF. = I® 21' } T7 4. ^ DifF.= i".322lU"^^^^'^y- The small star is blue, and bears a good illumination. Observed on the meridian. Mean Result. Position 85° 6f sf; Distance 59^.280; Epoch 1825.04. Sir W. Herschel has no measures of this star. (H.) No. DCCXVIII. R. A. 19^ 25°^ ; Decl. 27° 54' N. Struve, 624 ; II. 99- Double; 8th and 12th magnitudes. Passy ; September 27, 1824 ; Seven -feet Equatorial. Position =87° 18' «/ 1 5 Obs. Diff. = 2° 35' ) ^ . , ,.^ ,, Distance = 8''.oo5 | 5 Obs. Diff. = 2".i 15 5 Excessively difficult. The small star scarcely bears the least illumination. Night fine. Passy ; July 19, 1825 ; Seven-feet Equatorial. Position = 85° 35' nf\ 5 Obs. DifF. = 2° 5' ) „ • 1 j-xc 1. Distance =6'. 76 i | ? Obs. DifF. = o".84i j^^^^^^^^^y^^^^"^*' The small star is blue, and is so extremely obscure, that the results are somewhat suspicious. Night favourable. Passy ; July 31, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position = 85" 22' nf Distance =: 5". 908 5 Obs. 5 Obs. DifF! = o''.288 } Extremely difficult. Observed on the meridian : the small star is light blue, and bears a very feeble illumination. Night very fine. 932^ Mr. South's observations of the apparent distances No. DCCXVIII. continued. Passy ; August 1, 1825 ; Seven-feet Equatorial. 8th and 1 1th magnitudes. Position =84° 17' n/" e Obs. Diff. = i°35')p . . -..a- ,, Distance = 6^686 5 Obs. Diff. ^ o^.J^g i j ^^^^^^^^^^^ ^^^'^"^f- Stars tolerably steady, and on the meridian. Night fine. Mean Result. Position 85° 38' nf (20 Obs.) ; Distance 6".840 (20 Obs.) ; Epoch 1825.36. The angle in 1783 was 87° 48' ?z/, differing only 2® 10' from the present. Of course no change can be concluded. (H.) No. DCCXIX. R. A. 19^ 25°^ ; Decl. se"" 21' N. Nova ; Triple ; A of the 9th, B of the 10th, and C of the 9th mag- nitudes. Measures of A B. Passy ; July 24, 1825 ; Seven-feet Equatorial. Position = sz'' 36' nf I 5 Obs. DifF. = 3° 52' \ p„._™„,„ diffimlf- Distance z= 6".3 11 | 5 Obs. Diff. = d'.t^g \ iixtremely ditticult. Night very favourable ; stars very steady ; but the smaller one is faint. Observed on the meridian. Passy ; July 27, 1825 ; Seven-feet Equatorial. Position = 34° 49' nf] 5 Obs. I DifF. = 2° iz' 1 „ difficult , Distance = 6".28o j 5 Obs. | DifF. = o".673 ] ^^^^ difficult. The small star is indistinct : the night very fine. Passy; July 28, 1825; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 32° 55' ra/l 5 Obs. 1 DifF. =: 2° 1'. Very difficult. Stars very steady, but the small one scarcely bears any illumination. and positions of 45^ double and triple stars, &c. 233 No. DCCXIX. continued. Measures of A C. Passy ; July 24, 1825 ; Seven-feet Equatorial. Position = 24° 38' n/or sp I 5 Obs. DifF. = 1° 13' ? Satisfactory Distance = S3".i69 | 5 Obs. DifF. = o".553 5 Satisfactory. By directing the eye to another part of the field, I can suspect the star C to be double ; if so, its small star is more minute than the small one of a Lyrae ; is south preceding, and is rather nearer to C, than is B to A. Night remarkably fine; stars very steady. Passy; July 27, 1825 ; Seven-feet Equatorial. Position = 24° 54' n/or sole Obs. I DifF. = 2° 28' i ,r .. j Distances 53".287 | 5 Obs. | Diff. = o".529l ^^^ '^^^^y- Each star of the 9th or 9^ magnitude, but occasionally indistinct. Mean Result. of AB. Position 33° 27' w/(i5 Obs.); Distance 6". 295 (10 Obs.); of AC. Position 24'' 46' nf; Distance 53''.228 ; Epoch 1825.57. No. DCCXX. R. A. 19^ 27"^ ; Decl. 10** 33' S. Struve, 625 ; I. 13; Double; 8-|- and 12th magnitudes. Passy ; July 18, 1825 ; Seven-feet Equatorial. Position =44° o' np \ c Obs. DifF. =4° 41' } ,, j.^. ,^ Distance = 7.1 35 | 5 Obs. DifF. = 5". j6o J ^^^^ ^^^<="1*- The small star is light blue, and bears only a very feeble illumination. Night clear, but the stars of low altitude are very unsteady. Passy ; July 28, 1825 ; Seven-feet Equatorial. 8 J and 12th magnitudes. Position = 46° 23'«p I c Obs. I DifF.= 3° 40' ) ^ . , ..n- ,, Distance =4".S7o ^ | 5 Obs. | Difi^.= o".36oi Excessively difficult. The night is very favourable for difficult observations ; but although the stars are very steady, yet the measures are so extremely difficult, that I fear they merit but little confidence. Sir W. Herschel having described it as a triple star, I applied a power of 413, but no third star could be even suspected. MDCCCXXVI. h h 234 Mr. South's observations of the apparent distances No. DCCXX. continued. Passy ; August 10, 1825 ; Seven-feet Equatorial. 8f and 1 1th magnitudes. Position = 47° 36' np I 5 Obs. Diff. = +;; 35' \ Excessively difficult. Distances 4 .166 j 5 Obs. Diff. = o".84i > ' Observed on the meridian. Stars steady, yet the measures are unsatisfactory : the small one is pale blue, and does not bear a good illumination. Passy ; August 20, 1825 ; Seven-feet Equatorial. 8^ and 11th magnitudes. Position = 460 14' np I 5 Obs. 1 Diff. = 4° 3' \ Excessively difficult. Distance = 5 .075 | 5 Obs. | Diff. = o .745 3 ' Observed on the meridian ; night favourable ; small star blue, and scarcely bears any illumination. Mean Result. Position 46° s' np (20 Obs.) ; Distance 4".488 (20 Obs) ; Epoch 1825.59. Sir W. Herschel's measures of this star stand as follows : 1782.77 37° 15' n p. Mean of tv^o measures. 1802.76 44° 45' np. This star then appears to be subject to a slow motion, amounting to about + o°.i48 per annum ; but the data are too precarious to speak with certainty. (H.) No. DCCXXI. R. A. 19^ 29*"; Decl. 16° 4'N. £ Sagittae ; Struve, 628 ; VI. 26. Double ; 5th and 9th, or 10th magnitudes ; small, blue. Blackman-street ; July 11, 1824; Five-feet Equatorial. Position = 8° 56' nf 5 Obs. 1 Diff. = 1° 15' ) ^ . Distance = 1' 3i".54i 5 Obs. | Diff. = d'.s^s] ^* and positions of ^58 double and triple stars , &c. 235 No. DCCXXI. continued. Passy ; July 15, 1825 ; Seven-feet Equatorial. 5 th and 9th magnitudes. Position = 8» 58' nf I 5 Obs. I Diff. =■• 0° 33' ) ^^ ,„ . , „^,„ . Distance = 1' 32''.286 | 5 Obs. | Diff. = o''.62S J Tolerably steady. Mean Result. Position 8<» 57' nf; Distance 1' 3i".9iS ; Epoch 1825.03. This star affords an instance of very exact coincidence of measures with those ef Sir W. HERSCHELin 1782, which are 8" 32' nf for the position, and for the distance 1' 31" 9 " extremely exact." (H.) No. DCCXXII. R. A. 19^ 29"; Decl. 17° 19' S. Struve, 627 ; Hist. Csel. 116. Double ; 8th and 8 1- magnitudes. Passy ; July 16, 1825 ; Seven-feet Equatorial. Position = 33° i' sp] c Obs. Diff. = i° 48' ) ^ . , ^ . Distance = io".86/ | 5 Obs. Diff. = o".T2o} Extremely unsteady. Observed on the meridian. Passy ; July 18, 1825 ; Seven-feet Equatorial. 8| and 8| magnitudes. Position = 32*' 30' «p c Obs. I Diff. = 0° 57' ) ^ ^ , , . Distance = lo-'.-J/S 5 Obs. | Diff = o".745 5 ^^^'"^"^"^y unsteady. Observed on the meridian. Mean Result. Position 32° 45' sp ; Distance io".669 ; Epoch 1825.54. 236 Mr. South' s observations of the apparent distances No. DCCXXIII. R. A. 19^ 36" ; Decl. lo' 21' N. StRUVE, 632 ; I. 91. Double ; 8t and 11th magnitudes. Passy ; July 18, 1825 ; Seven-feet Equatorial. The small star is decidedly light blue, and is rendered rather more distinct by slight illumination ; under however sufficient to show the wires of the micrometer pleasantly, it becomes invisible : the measures are excessively difficult, and some degree of suspicion attaches to the results. Night remarkably clear, but the stars are not steady. Passy ; July 28, 1825 ; Seven-feet Equatorial. 8th and 13th magnitudes. Position rs 6° 26' np j 5 Obs. Distance =:4".2 1 9 j 5 Obs. 20 minutes east of the DifF. =: 3° 20' ) 20 minutes Diff. zz o".36o 5 meridian. Measures excessively difficult : stars very steady j the small one is blue. Mean Result. Position 6° 9,*j' np\ Distance 3".994 ; Epoch 1825.56. Sir W. Herschel's measures are — 1783, Position 8° iS' np, and 1802, 12° 23' np. These, discordant as they are with the present measure and with each other, yet afford some- what of a presumption of a very slow change of position in the direction np s J or retrograde. ( H. ) No. DCCXXIV. R. A. 19^ 59''' ; Decl. 20° 30' N. Nova ; Double; 9th and 11th, or 12th magnitudes. Passy ; August 17, 1825 ; Seven-feet Equatorial. Position = 6° 45' sp 5 Obs. DifF. = 0° 30' ) e„„,_:„_i„ difficult Distance = 4".87 1 5 Obs. Diff. = o".s53 5 Excessively ditocult. The small star is light blue, and becomes more distinct by a slight illumination ; yet the measures are so excessively difficult, that it will be useless to attempt ob- serving it, except under the most favourable circumstances. The present is a night peculiarly fine, and the stars are remarkably steady and well defined. and positions of 4f5S double and triple stars, &c. 237 No. DCCXXIV. continued. Passy ; August 20, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position = 6° 24' s j) I 5 Obs. Distance r= 5".374 | 5 Obs. Diff! = o^ss's } Excessively difficult. This star is also double of the 5th class. By directing the eye to another part of the field, a star of the 15th or 20th magnitude may be perceived almost directly preceding. No measures of it however can be obtained with this instrument ; yet the night is favourable, and the observations are made on the meridian. Mean Result. Position 6° 34f sp; Distance 5"- 122; Epoch 1825.63. No. DCCXXV. R. A. 19*^ 39"^ ; Decl. 34" 37' N. Struve, 638 ; V. 137. Double; 7th and 10th magnitudes; small, decidedly blue, and bears a very good illumination. Blackman-street ; July 11, 1824 ; Five-feet Equatorial. DifF. = I* 14' i TT . J Position =s 61" 2' nf I 5 Obs. Distance = 39". 127 | 5 Obs. Passy ; July 19, 1825 j Seven-feet Equatorial. 6th and 9th magnitudes. Position = 6o«> 37' nf \ 5 Obs. I Diff. = i° 8' ( q. . Distance = 38".398 | 5 Obs. | Diff. = i".oip5 ^^^^^Y' Passy ; July 31, 1825 ; Seven-feet Equatorial. 6th and 9th magnitudes. Position = 60° 47' n/ 1 c Obs. I Diff. = 0° 28') ,, „ ^. . ^ Distance = 38".709-^ | 5 Obs. | Diff. = o".336l Very satisfactory. Mean Result. Position 60° 49' nf(is Obs.) ; Distance 38". 745 ( 15 Obs.) ; Epoch 1825.22. The position in 1783 was 57* 3* nf, differing only 3<* 46' from the present angle. There is an apparent increase of distance to the amount of + 3". 73 since that epoch ; but this is very precarious. (H ) 2s8 Mr. South's observations of the apparent distances No. DCCXXVI. R. A. 19** 4o"» ; Decl. 32" 27'N. ^ Nova ; Double ; 7th and 9th magnitudes. Passy ; July 24, 1825 ; Seven-feet Equatorial. Position = 63° 23' j/> I 5 Obs. Distance = 33".227 j 5 Obs. giffiis-ifsl^^-f"'"-^- The small star is blue, and bears a very good illumination. Night very favourable ; stars remarkably steady. Passy ; July 25, 1825 ; Seven-feet Equatorial. 7 th and 9| magnitudes. Position = 630 37' sp I 5 Obs. I Diff. = i°3s' 7 Unsteadv Distance = 33".662 | 5 Obs. | DifF. = o".9i 3 | unsteady. Observed on the meridian : the small star is blue. Mean Result. Position 63° 30 'sp; Distance 33".444; Epoch 1825.56. No. D CCXXVII. R. A. 19^ 43" ; Decl. 0° 2' N. Struve, 644 ; II. 95- Double; 9^ and 10th magnitudes. Passy ; September 24, 1824 ; Seven-feet Equatorial. Position = 260 53' np I 5 Obs. I Diff. = ,° 38' J Very difficult. Distance = 5 .472 \ 5 Obs. | Diff. = o .7933 ' The dew collects so rapidly on the object-glass, although a tube of pasteboard projects 12 inches beyond the object-end of the telescope, that to see these stars it is absolutely necessary to wipe it between each measure j but the stars are well defined, and are unusually steady. Passy ; July 20, 1825 ; Seven-feet Equatorial. 9th and 9J magnitudes. Position = 26° 31' np Distance = 5".703 5 Obs. 5 Obs. 5i£- ~ \° 35' ] Extremely difficult. Diff. = o".793 3 ^ These stars are of a pale blue colour, and neither bear illumination nor magnifying power. Observed on the meridian. and positions of ^58 double and triple stars, &c, 239 No. DCCXXVII. continued. Mean Result. Position 26° 42' w/ ; Distance 5". 58 7 ; Epoch 1825.14. The measures of 1783 and 1802 give 29° s' npy and 30*" q' np respectively for the angles of position. The esti- mations in diameters of the distance correspond to about 5 or 6" central distance. This star therefore has not varied sen- sibly. (H.) No. DCCXXVIII. R. A. 19^^ 43"" ; Decl. 43° 55' N. Struve, 64s; III. 112. Double; 8th and 8i magnitudes. Blackman-street ; June 28, 1824 ; Five-feet Equatorial. Position = 69° 42' sf Position = 69° 45' sf Distance = io".789 5 Obs. 5 Obs. 5 Obs. DifF. = 1° 45' ■) South. DifF. = 2° 34' \ Mr. Richardson. DifF.= o".gi6} South. The night is become so bad, no more observations can be gotten. Passy ; July 15, 1825 ; Seven-feet Equatorial. 8| and 8J magnitudes. Position = 71° 2'*/ 1 5 Obs. I DifF. = i° o' ^ y . Distance = io".454 | 5 Obs. | Diff. = o''.2645 ^ ^' Passy ; August 31, 1825 ; Seven-feet Equatorial.* 8th and 8| magnitudes. Position = 71° 2' sf\ 5 Obs. I Diff. = 1° 21' I Tolerably steadv Distance = io".ioi | 5 Obs. | Diff. = o".36o5 ^o^e^ably steady. Mean Result. Position 70° 23' sf(2o Obs.); Distance io".4i5 (15 Obs.); Epoch 1825.23. This position differs only o° S7' from that of 1783. The distances too present an exact correspondence, Sir W. Hers- chel's measure being 10". 140. (H.) 240 Mr, South's observations of the apparent distances No. DCCXXIX. R. A. 19'' 52" ; Decl. 35° s' N. Nova;. Triple ; A of the 9th, B of the 10th, and C of the 6th magnitudes. Measures of A B. Passy ; July 24, 1825 ; Seven-feet Equatorial. Observed on the meridian ; stars very steady. Night fine. Passy ; July 28, 1825 ; Seven-feet Equatorial. 9J and 10th magnitudes. Position = «6° ic' np \ c Obs. I DifF. = 2° 22' 7 tt „, ^;fl;,.»u Distance = 4".i7S | 5 Obs. | DifF. = o".336 S ^"^ ^'®'''^*- Observed on the meridian. Night very favourable. Measures of A C. Passy ; July 24, 1825 ; Seven-feet Equatorial. 9th and 6th magnitudes. Position = 34° 16' sp I 2 Obs. DifF. = o* 2' ) ^ . ^ Distance = 4' 3".859 | 2 Obs. DifF. = o".240 5 ^^ ^* (C being to the south of A.) Passy ; July 28, 1825 ; Seven-feet Equatorial. 9| and 6th magnitudes. Position = 34O8' sp 2 Obs. DifF. = 0° 11' ) ^•■t,^ c„„ * Distance = 4' i'.9io 2 Obs. DifF. =:o".2i6 J ^^^^^ fi'^^* (C being to the south of A.) Mean Result. of A B. Position 25° 47' np ; Distance 4".si8 ; of A C. 34° 1^' sp; 4' 2".884 ; Epoch 1825.57. and positions 0/4,58 double and triple stars ^ &c» 241 No. DCCXXX. R. A. 19^ 52"^; Decl. 17** fN. Nova ; nf x Sagittse ; x only seen single. Double ; 7^ and 8th magnitudes. Blackrnan-street ; July 13, 1824 ; Five-feet Equatorial. Position = 74° 20' nf I 5 Obs. Distance = i' ^^".6\z \ 5 Obs. DifF. =o°32 I DifF.= i".23i ] (Same date and Insti'ument.) Measures of x with the brightest of this double star. Position = 77° 7' sp Distance = 5' 4o".5i6 2 Obs. 2 Obs. F. =: o» 12' ) F. = o".2845 Diff. =: o» 12' Diff. {x preceding to the south.) Passy ; July 20, 1825 ; Seven-feet Equatorial. 6th and 9th magnitudes. Position = 74- o' «/ I 5 Obs. I DifF. = o° 56' ) Unsteady Distance = i' 56".22o | 5 Obs. [ DifF. =o".72i ] ^^steaay. Mean Result. Position 74° \d nj\ Distance 1' s^' .9?>^ ; Epoch 1825.04. Of X Sagittae and the brightest of this double star, Position 77° 7' ; Distance 5'4o"5i6 (% preceding to the south.) No. DCCXXXI. R. A. 19^ 53" ; Decl. 46° 54' N. Nova ; Double ; 9th and 9! magnitudes. Passy ; September 1, 1825 ; Seven-feet Equatorial. 6 Obs. 5 Obs. wff:=o'.«2}™"''"'"""'''- Position zz 62° 5 1' nf Distance n 5".432 Observed on the meridian. Night favourable. Passy ; September 2, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Iff: = 0^360 l^^^h^^di^^^i^- Diff. = Diff. Position = 64° 11' »/| 6 Obs. Distance =: 6". 191 | 5 Obs. Observed on the meridian ; stars very steady. MDCCCXXVI. / i 242 Mr. South' s observations of the apparent distances No. DCCXXXI. continued. Passy ; September 4, 1825 ; Seven-feet Equatorial. Equal; each of the 11th magnitude. Position s= 63° 4' sp or nf Distance = 6".^qo ^ n^- i n^- = ^'' f I Extremely difficult. 5 Obs. I DifF. = o .360 3 ^ Night very hazy. Should these observations accord with one set already taken more than with the other, they must not be received to the exclusion of the discor* dant series. Passy ; September 5, 1825 ; Seven-feet Equatorial. Equal ; each of the 9th magnitude. 6 Obs. 5 Obs. Observed on the meridian. Night hazy. Position = 64® ^' sp or nf Distance = 5".494 ^1^-=^: 37' I Difficult. Diff. = o .240 5 Passy; September 6, 1825 ; Seven-feet Equatorial. Equal; each of the 10th magnitude. Position = 62° 52' sp or »/ [ 6 Obs. ) DifF. = 3° 7'. Very difficult. Stars tolerably steady j but the night is so extremely hazy, that no observations of distance can be procured. i -n Passy; Septembers, 1825; Seven-feet Equatorial. 9^ and 10th magnitudes. Distance =: 6".282 | 5 Obs. | DifF. = o".793. Extremely difficult. Night so hazy, that the stars are only visible by glimpses. Passy ; September 9, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Distance = 6". 150 | 5 Obs. | DifF. = o''.745. Tolerably steady. Mean Result. Position 63° 24' sp or nf (so Obs.) ; Distance 5". 99^ (so Obs.) ; Epoch 1825.68. and positions 0/4,^8 double and triple stars ^ ^c, 243 No. D CCXXXII. R. A. 20»» o"^ ; Decl 20° 36' N. Nova; Double ; 9th and nth, or 12th magnitudes. Passy ; August 17, 1825 ; Seven- feet Equatorial. Position = 70° 3/«P I 5 Obs. I DifF. = 2" 17' ^ Excessively difficult Distance = ^'.^17 \ 5 Obs. | DifF. = o".456> Excessively aimcult. The small star is pale blue, and is rendered more distinct by slight illumination ; yet the measures are so excessively difficult, that it is useless to attempt observing it except under the most favourable circumstances, such as the present, when the stars generally are remarkably brilliant, and when they pass through the field of the telescope as steadily as possible. Observed 35 minutes east of the meridian. Passy ; August 20, 1825 ; Seven-feet Equatorial. 8th and 11th or 12th magnitudes. Position = 71° 23' np I 5 Obs. I DiflF. = i" 56' ) ,, . , ..^ ,^ Distance = ^",719 | 5 Obs. | Diff. = o".i845 Excesssively difficult. The small star, which is pale blue, bears but a very feeble illumination. Night favourable. Mean Result. Position 71° o' np-. Distance 4".5i8 ; Epoch 1825.63. No. DCCXXXIII. R. A. 2o'» 2- ; Decl. 34° 57' N. Nova ; Double ; Sf and 9^ magnitudes ; bear a good illumination. Passy ; August 1, 1825 ; Seven-feet Equatorial. Position = 32° 24' np c Obs. I DifF. = 2° 20' \ ^j ^ , Distance =:5".6oJ "^ 5 Obs. | DifF. = o".36o J ^^^ ^^^^'^y- Observed on the meridian. Night very fine. Passy ; August 9, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 33* 12' «j) 15 Obs. Distance =: 5*.! 11 J 5 Obs. Diff- = »°»°' J Very difficult, '5 3 ' DifF. = o".505 Night hazy. Observed on the meridian. Mean Result. Position 32° 4>S' np; Distance 6'"S55 ; Epoch 1825.59. 244 Mr. South' s observations of the apparent distances No. DCCXXXIV. R. A. 20^ 2" ; Decl. 16° 16^ N. Struve, 659 ; II. 70. Double ; 8th and 11th, or 12th magnitudes. Passy ; August 20, 1825 ; Seven-feet Equatorial. Position =740 41' n/l c Obs. DifF. = i° 52' ) ^^ . , ,.«. ,^ Distance=6".682 "^ | 5 Obs. DifF.=o".36oP^^"^^^^^y ^'^^"^^- Night very favourable ; but the small star will scarcely bear any illumination. Passy ; August 21, 1825 ; Seven-feet Equatorial. 8th and 1 1 th magnitudes. Position =76° 7' nf 5 Obs. DifF.= o° 20' 1 K„cessivelv difficult Distance=6".S28 5 Obs. DifF. = o".48i \ Excessively diflicult. The small star, which is light blue, under a very slight illumination becomes invisible. Mean Result. Position 75° ^4f nf'. Distance 6*.6o5 ; Epoch 1825.64. There is no evidence of a change of position in this star. Its position in 1783 was 72° 57' w/. Its distance, estimated at 2 diameters between the discs, may correspond to a central distance of about 4, 5, or 6 seconds, according to the atmo- spheric or other circumstances at the time of observation. (H.) No. DCCXXXV. R. A. 2o»> 2- ; Decl. o" 40' S. Struve, 661 ; P. XX. 11, 12; V. 136. Double ; 7^ and 8th magnitudes. Blackman-street ; July 11, 1824 ; Five-feet Equatorial. Position = 68° 7' «;? 5 Obs. j DifF. = 1° 40' \ Distance = 54". 362 5 Obs. | DifF. = o".9i3 5 • • . • Passy ; November 3, 1824 ; Seven -feet Equatorial. 7 J and 8th magnitudes. Position = 6^° 33' *p I 5 Obs. I DifF. =: 1° 26' ) Distance = 54^768 | 5 Obs. | DifF. = i".443 5 • • v • and positions 0/4,58 double and triple stars ^ ^c. 245 No. DCCXXXV. continued. Passy ; August 10, 1825 ; Seven-feet Equatorial. 8th and 8^ magnitudes. Position = 67° 29' sp 5 Obs. DifF. = o° 35' ) y . Distance = 54".88i 5 Obs. Diff. = o".g6z ]^^^ ^^^°^' Observed on the meridian. Night hazy. Mean Result. Position 67° 4S' sp (15 Obs.); Distance 54^670 (15 Obs.) ; Epoch 1825.01. The present result differs only i° Bb' in position from Sir W. Herschel's measure in 1783. (H.) No. DCCXXXVI. R. A. 20^ 2- ; Decl. 20° 22' N. 6 Sagittae ; Struve, 660 : III. 24. Triple ; A of the 6th, B of the loth or 11th, and C of the 7th magnitudes. Measures of A B. Blackman-street ; July 4, 1824 ; Five-feet Equatorial, Position = 58° i' rap I 5 Obs. 1 DifF. = i° 47' } _. ,._ , Distance = i i'.jiS | 5 Obs. DifF. = o".7zi \ ^^^ ^^^cu\t. Observed on the meridian j the small star does not bear a good illumination. Passy ; November 3, 1824 ; Seven-feet Equatorial. 6th and 10th magnitudes. > Very difficult. Position, rr 58° 5' «p Distance r: 12". 161 5 Obs. 5 Obs. DifF. = 2° 48' Diff. = o".625 Passy ; August 12, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. Position = S7°\7'np I 5 Obs. I Diff = 1° 16' >. Unsteady Distance = 1 1".383 | 5 Obs. | Diff. = 0^577 j ^""eady. Observed on the meridian ; small star rather faints but the measures arc good. 246 Mr. South' s observations of the apparent distances No. DCCXXXVI. continued. Measures of A C. Blackman-street ; July 4, 1824 ; Five- feet Equatorial. 6th and 7 th magnitudes. Position =43° 16' sp Distance = i' io".402 5 Obs. I DifF. = 0° 1 3' ) 5 Obs. I DifF. = o".432 3 Passy ; November 3, 1824 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position = 43* 39' sp Distance == i' 9".839 5 Obs. 5 Obs. DifF. = 1° 40' ) DifF. = i".635> Passy ; August 12, 1825 ; Seven-feet Equatorial. 7J and 8th magnitudes. Position = 42° 39' sp I 5 Obs. I DifF. = 0° 31' ) Unsteady Distance = i' io".022 | 5 Obs. | DifF. = i".75s 5 ^^steaay. Mean Result. of A B. Position 57° 58' np (15 Obs.) ; Distance ii".777 (i5 Obs.) of AC. Position 43° n' sp (15 Obs.); Distance 1' io".o88 (15 Obs.) Epoch 1824.98. Sir W. Herschel has no measures of the positions of these stars. The distance of A B he makes 11" 4/", agreeing pretty well with the present ; while that of A C is stated by him at 59" 49'", a convincing proof of some cause of error in the micrometer when opened to considerable distances, and which has been already alluded to. What this cause of error may have been, whether parallax, or the resistance of a spiral steel spring straining the threads of the screw immoderately, it is useless now to enquire ; but the whole tenor of the observations goes to prove, that distances less than 20 or 30" are not affected by it. (H.) and positions of 458 double and triple stars, &c. 247 No. DCCXXXVIL R. A. 20^ 2™ ; Decl. 20° 25' N. Nova ; Double; 8th and 10th magnitudes, Blackman-street ; July 4, 1824 ; Five- feet Equatorial. Position == 39° 33' sf Distances i' /^I'.zgo 5 Obs. 5 Obs. n-ffZi°^',,{ Difficult. Dm. = o".727 ) Passy ; November 7, 1824 ; Seven-feet Equatorial. 8th and 1 1th magnitudes. Position =: 39** 15' sf Distance = i' 40". 848 5 Obs. I Di£F.= .<' 30- j Very difficult. 5 Obs. I Diff. = 3".474 Small star blue, and very faint. Night hazy. Mean Result. Position 39° ^4f sfi Distance i' 4i".o69 ; Epoch 1824.68. No. DCCXXXVIII. R. A. 20^ 4" ; Decl. 33° 7' N. Struve, 663 ; Hist. Gael. 297. Double ; 8th and 9th magnitudes ; small, blue. Blackman-street ; July 11, 1824 ; Five-feet Equatorial. Position = 22° 41' sf I 5 Obs. I DiflF. = 0° 45' | Distance = 4i".842 j 5 Obs. | Diff. = ©".569 j • • • . Passy ; November 7, 1824 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 21° 49' sf\ 5 Obs. I Diff. = 0° i6' ) Distance =: 4i".883 | 5^bs. | Diff. = i".o82 ] • • • • Mean Result. Position 22° 15' sf; Distance 4i''.862 ; Epoch 1824.69. 248 Mr. South' s observations of the apparent distances No. DCCXXXIX. R. A. so'^ 5" ; Decl. 6° ss' S. Nova ; Double ; 8th and 10th magnitudes. Passy ; September 2, 1825 ; Seven-feet Equatorial. Position = 39: -' -/ 1 S Obs I Diff. = .° 8' | ^^^^^^ ^.^^^^^^ Distance =: 25 .128 j 5 Obs. | DiiF. =: o .889 3 Observed on the meridian ; stars tolerably steady. Passy ; September 9, 1825 ; Seven-feet Equatorial. 8th and 11 th magnitudes. Position = 39° 23' nf \ 2 Obs. | DifF. =z 0° 54'. Extremely difficult. Night is now so hazy, that the small star is no longer visible. Passy; September 10, 1825 ; Seven-feet Equatorial. 8th and 1 1th magnitudes. Position = 39° 31' «/| 5 Obs. I Diff. = 2° 9' \ Extremely difficult. Distances 25". 104 | 5 Obs. j Diff. = i".370 > ' Night hazy ; the small star is bine. Mean Result. Position 39° 26' w/(i2 Obs.); Distance 25".! 16 (10 Obs.); Epoch 1825.69. No. DCCXL. R. A. 20^^ 5™ ; Decl. 6° 4' N. Struve, 664 ; P. XX. 43, 44. Double ; equal ; each of the 7th magnitude. Blackman-street ; July 4, 1824 ; Five-feet Equatorial. Diff. = 0° 46' ) Diff. = i".42ij • . • . Observed when i** 15' east of the meridian, but the stars are very steady. Position = 77° 9' *j9 or nf Distance = 44".07o 5 Obs. 5 Obs. Passy; November 6, 1824; Seven-feet Equatorial. Equal ; each of the 8th magnitude. Position zz 77° li' sp or nf Distance = 43^7 17 5 Obs. 5 Obs. Diff. = 1° 43' Diff. . = i".i78 5 • • • . Mean Result, Position T '7° 11' sp or nf; Distance 43". 893 ; Epoch 1824.67. and positions of 4<5S double and triple stars , &c. 249 No. DCCXLI. R. A. 20^ 7" ; Decl. 21° 45' N. Nova ; Triple ; A 8th, B 8 J, and C of the 12th magnitudes. Measures of A B. Passy ; August 1, 1825; Seven-feet Equatorial. Position = 850 42' nf 5 Obs. I Diff. = i» 37' ) npolerablv steadV Distance= 7".o33 5 Obs. | Diff. == o".456 5 ^ olerably steady. Passy ; August 9, 1825 ; Seven-feet Equatorial. 8th and 85 magnitudes. Position = 860 45/ „y I 5 Obs. I Diff. = 1° 42' ) E„fremelv unsteady Distances: 6".26s | 5 Obs. | Diff. = o".649 ] Extremely unsteady. Night hazy ; stars 20 minutes west of the meridian when observed. Passy ; September 2, 1825 ; Seven feet Equatorial. 8^ and 9| magnitudes. Distance = 6".465 | 5 Obs. | Diff. = ©".336. Very hazy. Passy ; September 15, 1825 ; Seven-feet Equatorial. 8th and 85 magnitudes. Distance == 5".992 | 5 Obs. j Diff. = o".6/^g. Steady. Measures of A C. Passy; August 1, 1825; Seven-feet Equatorial. 5 Obs. ( Diff. z= 1° 55' ) .. ,.n, ,^ 5 Obs. I Diff. = o".i8i > ^^"y ^^®^^^*- Position — 60° is' sf Distance = 5 8". 156 8th and 12th magnitudes. Passy ; September 2, 1825 ; Seven-feet Equatorial. 8| and 12th magnitudes. c Obs. I Diff. = 1° 40' ) „ . , j.rx: ,^ c Obs. Diff. = o".Q I ^ \ Excessively difficult. Position =5 60° 8' */ Distance = s^".6g^ 5 UDs. I uiir. = o .913 ) The small star bears but the slightest illumination, and the observations, particu< larly of distance, are a little suspicious. Night hazy. ; 3-: hr: ' Passy; September 15, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Distance i^ 57'.i24 j 5 Obs. J Diff. = o''.8i7. Excessively difficult, MDCCCXXVI. k k 250 Mr. South's observations of the apparent distances No. DCCXLI. continued. "-'^-'^ ' Mean Result. of A. B. Position 86° 13' nf (10 Obs.) ; Epoch 1825.59 ; Distance 6".^S9 (20 Obs.) ; Epoch 1825.64. of AC. Position 60° 12' 5/(10 Obs.); Epoch 1825.62 ; Distance 57*.325 (i5 Obs.) ; Epoch 1 835.^5- No. DCCXLII. R. A. 20^^ 8- ; Decl. 46« 12' N. 0^ Cygni ; Struve, 667 ; VI. 10. Double ; 5th and 8th magnitudes. Blackman-street ; June 28, 1824 ; Five-feet Equatorial. Position = 840 o' sf Distances: i'46".376 5 Obs. I DifF. = o<> 15' ) 5 Obs. I Diff. = i".o42> Observed when 4 hours east of the meridian. Passy; November 3, 1824 ; Seven-feet Equatorial. 5 th and 8th magnitudes. Position =83° 47' sf Distance = i' 46".4io 5 Obs. I Ditf. = 0° 35' ) 5 Obs. J DifF. = I ".250 Mean Result. Position 8s° 5s* sj; Distance 1' 46".393 ; Epoch 1824.66. The position of 1781 is 87° 14' sp, differing 8° 53' from the present ; an extraordinary change for a star of the 6th class, and one so easy of measurement. In Piazzi's cata- logue, a proper motion of — o".03 in R. A. and +o''.i8 in declination is ascribed to the large star. This should carry the large star almost directly away from the small one (and indeed there is an apparent increase of 6" in the distance, could the earlier measure be relied on) ; but no sensible change of angle could thus arise. This star should be re- measured after a lapse of 20 or 30 years. (H.) and positions of 458 double and triple stars, &c, 251 No. DCCXLIII. R. A. 20^ 10'" ; Decl. 47" 10' N. 32 Cygni ; Struve, 669 ; VI. 32.* Double ; 5th and 9th magnitudes. Blackman-street ; June 28, 1824 ; Five-feet Equatorial. ' Position = 85° 34' sf I 5 Obs. DifF. = 0° 18' \ Distance = 3' 28".972 I 5 Obs. DifF. = o".769 5 • • • • Passy ; November 3, 1824 ; Seven-feet Equatorial. 5th and 9th magnitudes. Position = 85° 34' sf J 5 Obs. DifF. = 0° 32' ) Distance = 3' 28".o2i | 5 Obs. DifF. = i^s^V § • ' ' ' Mean Result. Position 85° 34' sf; Distance 3' 28".496 ; Epoch 1824.66. No. DCCXLIV. R. A. qo^ ii-^ ; Decl. 12° 28^ N. .!ifDn Nova; Double ; 8^ and 8|- magnitudes. Passy ; July 29, 1825 ; Seven-feet Equatorial. Position =52° 50' np I c Obs. I DifF. = o° 57' ) ^ . Distance = l8".562 "^ \ 5 Obs. | Diff. =o".2;o J ^""^ measures. Observed on the meridian ; stars tolerably steady. Passy ; July 31, 1825 ; Seven-feet Equatorial. 8| and 8| magnitudes. Position = 52° 51' n/) Distance = 28".205 S Obs.* I Diff! = o''.2f8} ^^^y satisfactory. Mean Result. Position 52° 51' w/> ; Distance 28". 383 ; Epoch 1825.58. * So called in Struve's Catalogue, but erroneously* VI. 32 is ^ Cygni R. A, 26^ 40"". (H.) 352 Mr. SouTH*s observations of the apparent distances No. DCCXLV. R. A. 20»^ li™ ; Decl. 15° 21' S. jQ Capricorni ; Struve, 670 ; VI. 28. Triple ; A 5th, B of the 7th, and C of the 10th magnitudes. Measures of A B. Blackman-street ; July 12, 1824 ; Five-feet Equatorial. Position —z^s^sp I 5 Obs. I DifF. = 0° 23' \ Distance = 3' z^'.ioo \ 5 Obs. | DifF. = o".6oo5 • • • • Passy ; November 7, 1824 ; Seven-feet Equatorial, 6th and 8th magnitudes. Position = 2° 55' sp 5 Obs. I Diff. z= 0° 29' ) ^ ^ Distance = 3' 23".330 5 Obs. | DifF. = i".0345 ^^^ "^^y- Observed when i hour west of the meridian. Measures of A C. Passy; November 9, 1824; Seven-feet Equatorial. 6th and 10th magnitudes. Position = 43° 27' */ 1 5 Obs. I DifF. = 0° 25' ) ,, „, Axair.„u Distance= 3' 46'.86i | 5 Obs. | DifF. = ,".803 j^ery difficult. Night hazy; small star is extremely faint. Passy ; August 31, 1825 ; Seven-feet Equatorial. 5 th and 11th magnitudes. Position = 43° 54' sf I 5 Obs. I DifF. = 0° 42' 1 Extremely difficult Distance = 3' 46".57i | 5 Obs. | DifF. = o".889 5 ^^^^^"^^^^ ^^"^^"^'^* Observed on the meridian j small star is blue, and bears only a very slight illumination. Mean Result. of A B. Position 2° 54' sp ; Distance 3' 23''.715 ; Epoch 1824.69. of A C. Position 43° 4o' sf-. Distance 3' ^6"*li6 ; Epoch 1825.35. Sir W. Herschel has given no measures of this star. (H.) and positions 0/4,58 double and triple stars, &c. 253 No. DCCXLVI. R. A. 20^ 12' ; Decl. 45° 4' N. . Struve, 671 ; Hist. Csel. 240. Double ; 9^ and 10th magnitudes. Black man-street ; July 12, 1824 ; Five-feet Equatorial. Position = 43° 59' « J9 I 5 Obs. Distance = 9". 143 j 5 Obs. Sft : l-i^} Difficult. Position = 42° S^'^P Distance = S".687 5 Obs. 5 Obs. Passy ; November 7, 1824 ; Seven-feet Equatorial. 9| and 10th magnitudes. dI«. = I".332 1 Excessively difficult. The Night has become so foggy, that I can observe no longer. Mean Result. Position 43° 28' ^'^ ; Distance 8".9i5; Epoch 1824.69. No. DCCXLVII. R. A. 201^ 14" ; Decl. 15° 50' N. Nova ; Triple ; A 9th, B gi, and C of the 15th magnitudes. Measures of A B. Passy ; August 1, 1825 ; Seven-feet Equatorial. Position = 62° 5' sf 5 Obs. DifF. = i° 13' 7 Rather difficult Distance = 3 i".5oo 5 Obs. DifF. = i".37o j father aitticult. The star B bears only an indifferent illumination. Passy ; August 12, 1825 ; Seven-feet Equatorial. 9th and 9? magnitudes. Position = 61° 16' */| 5 Obs. ( DifF. = !<> i' 7 difficult Distance = 3o".477 | 5 Obs. | DifF. = o".577 5 ^^™cuit. Neither of these stars will bear a good illumination. Passy ; September 2, 1825 ; Seven-feet Equatorial. 9th and 10| magnitudes. Distance = 3o".259 | 5 Obs. [ DifF. = o".745. Extremely difficult. The star B bears but the slightest illumination. 354 ^^' SouTH''s observations of the apparent distances No. DCCXLVII. continued. Measures of B C. Passy ; August 1, 1825 ; Seven-feet Equitorial. When the eye is directed to another part of the field, the southern star (B) is seen also double ; but its small star is so extremely faint, that to obtain any thing like measures of accuracy is impossible. Position = i7°,o' ± nf; Distance =13 seconds (by estimation). Passy ; September 2 1825 ; Seven-feet Equitorial. The star B is certainly double of the 2d or 3d class ; but its small star, which is nf, is so excessively obscure, that no observations of it can be procured. Night fine ; stars steady. Mean Result. A B. Position 61° 40' sf [10 Obs.) ; Epoch 1825.59 ; Distance 30". 745 (i5 Obs); Epoch 1825.62. B C. Position 17° ± n/j Distance 13 seconds. (Each by estimation.) No. DCCXLVIII. R. A. 20^ 18'° ; Decl. 13° 44' S. Struve, 675 ; Hist. Csel. 176. Double ; 9t and 10th magnitudes ; and bear but a very feeble illumination. Passy; September 17, 1824; Seven-feet Equatorial. Position = 23° 3 q'«/ c Obs. DifF. = i® 6')^ , ... Distance = 24".743 ^ 3 Obs. DifF. = 1". 1 30 J <^^ *^^ meridian. Night fine j stars steady ; but the measures are extremely difficult. Passy ; November 9, 1824 ; Seven-feet Equatorial. 9 J and 10th or 11 th magnitudes. Position = 23° 10' «/ 5 Obs. I Difi; = 1° 5' ) 35 minutes west of the Distance z=. 23". 659 5 Obs. j DifF. = i".587 5 meridian. Measures extremely dfficult ; the small star scarcely bears any illumination. Passy ; August 21, 1825 ; Seven-feet Equatorial. 10th and 1 1th magnitudes. Distance = 23".oo8 | 5 Obs. | DifF. =: o".84i. Excessively difficult. Night fine j but neither star will bear sufficient illumination. Mean Result. Position 23° 25' nf\ (10 Obs.); Epoch 1824.78 ; Distance 23".8o3 ; (15 Obs.) ; Epoch 1825.07. and positio7is 0/4,^8 double and triple stars, C^c. 255 No. DCCXLIX. R. A. 20^ iS" ; Decl. 2<> 42' S. Struve, 674 ; P. XX. 140. Double ; 6t and 7th magnitudes. Blackman-street ; July 12, 1824 ; Five-feet Equatorial. Position = 80° 57' *p I 5 Obs. I Diff. =: i" 13' ) Distance = 59^359 | 5 Obs. | Diff. = o".288 J * * * Passy ; November 6, 1824 ; Seven-feet Equatorial. 7^ and 8th magnitudes. Position = 8o° 24' « P I 5 Obs. l Diff. = 1° 10' ) ,.- u. . r ui Distance = i'o".ii9 | 5 Obs. | Diff.= i^yo;] Night not favourable. Passy ; August 14, 1825 ; Seven-feet Equatorial. 6^ and 7th magnitudes. Position = 8o° 25' * » I c Obs. I Diff. = o° 38' ) ,;. , . Distance = i' o".o39 I 3 Obs. | Diff. = 0^.240 ] ^^"^ ^^^^^y* Observations very satisfactory. Mean Result, Position 80° 35' sp (15 Obs.); Distance 59".872 (15 Obs.); Epoch 1825.00. No. DCCL. R. A. 20^ 22™ ; Decl. 25° 48' N. Nova; Double ; 8t and 8|: magnitudes. Passy ; July 29, 1825 ; Seven-feet Equatorial. Diff! = i''.o"4} Tolerably steady. Position = 54° 25' np I 5 Obs. Distance = i'6".932 | 5 Obs. Passy ; July 31, 1825 ; Seven-feet Equatorial. 8^ and 9th magnitudes. Position = 54° 1' np Distance = i' 6".49o 5 Obs. 5 Obs. I)^.z=°d'.%}^^'^^^^^y' Mean Result. Position 54° is' np\ Distance i'V.711 ; Epoch 1825.58. 356 Mr. South's observations of the apparent distances No. DCCLI. R. A. 20^^ 22"^ ; Decl. 10° 45' N. i5(Bode) Delphini; Struve, 681 ; III. 16. Double ; equal ; each 7th magnitude. Passy; October 5, 1825 ; Seven-feet Equatorial. Position = 13° 19' nfot sp \ 5 Obs. I DifF. = 1° 13' ) c-.._„ Distance = i4".662 | 5 Obs. | DifF. = o".889 5 =>o^th. Position = 13° 58' nf or sp 5 Obs. I DifF. = 1° 15' ^ Caot Beaufort Distance = i^-^jSz 5 Obs. \ DifF. = o".745 S ^ -Beaufort. Stars tolerably steady. Night fine. Passy ; October 7, 1825 ; Seven-feet Equatorial. Equal ; each 7| magnitude. Position = if 12' nf or sp\s Obs. I DifF. = 0° 37' ^ co„th Distance = i^'Mj | 5 Obs. | Diff. = o".673 j ^o^^h. Position = 1 3° 49' nf or sp I 5 Obs. I DifF. = i° 18' ) ^ M^.^r^r.^-r Distance = I4'.643 j 5 Obs. | DifF. = o'.456 J ^ Mean Result. Position is^SS' nf or sp (20 Obs.) ; Distance 14".689 (20 Obs.); Epoch 1825.76. The observation of 1781 makes the position of this star 9® 42' sp, and its distance 12" 5'" " exactly measured.'' The change in position is not considerable ; but an increase of 2".6 in distance, or more than a sixth, is rather too much to be attributed to errors of observation. (H.) No. PCCLII. R. A. 20^ 22" ; Decl. 18° 48' N. Struve, 678 ; Hist. Gael. 537. Double ; 7th and 7^ magnitudes. Blackman-street ; July 4, 1824 ; Five-feet Equatorial. Position = 18° $1' np Distance= 1' 45".4i5 5 Obs. I Diff. = 0° 58' ^ Very steady 5 Obs. I Diff. = o".4o8 5 ^^"^ "^^^J"* Observed wheii i** 45" west of the meridian. and positions 0/458 double and triple stars y &c. 257 No. DCCLII. continued. Passy ; November 6, 1824; Seven-feet Equatorial. 8th and S\ magnitudes. Position = 1 8° 22' np Distances: i" 44".35o 5 Obs. 5 Obs. iff. =:0°2I') „ , iff. =o".8i7j^^^y- Observed when 45 minutes west of the meridian. Passy ; August 10, 1825 ; Seven-feet Equatorial. 7th and 7i magnitudes. Position zz Distance -i I 5 Obs. | DifF. = 1° 17'. Excessively difficult. Observed with 157 ; the small star was not visible with i8i ; measures of distance impracticable. Mean Result. (Rejecting the angles observed September 27, 1824,) Position 49° 1' np (10 Obs.) ; Epoch 1825.^ ; Distance 55'', 791 (6 Obs.) ; Epoch 1825.20. No. DCCLVII. R. A. 20^ 26'" ; Decl. 27" 31' N. Nova ; Double; 9^ and 11th magnitudes; small, bluish. Passy ; August 17, 1825 ; Seven-feet Equatorial. Position = 32° 2' n« I s Obs. I DifF. = 3° 31' | „ • ^ a-o: ^. Distance = i".? 10 | 5 Obs. | Diff. = o".432 \ Excessively difficult. The small star scarcely bears any illumination. Observed on the meridian. Night very fine ; stars steady. Passy ; August 20, 1825 ; Seven-feet Equatorial. 9th and 11 th magnitudes. ^^S.W 1 S SbS: I ES:= 1".!^;} Excessively difficult. The small star, which is light blue, bears but the most scanty illumination. Night tolerably favourable for delicate observations. Mean Result. Position 31° ss' np ; Distance 4".468 ; Epoch 1 825.63. and positions of ^s^ double and triple starSy &c. 26ig No. DCCLVIII. R. A. qo^ 27"^ ; Decl. 13° 21' S. Struve, 685; Hist. Gael. 114- Double; 10th and 11th magnitudes; extremely faint, and scarcely bear any illumination. Passy; November 9, 1824 ; Seven-feet Equatorial. Position = 71*' 33' sp I 5 Obs. DifF. = 40 15' ) Excessivelv difficult Distance = io".267 | 5 Obs. DifF. = o".72i ] Excessively dimcult. Night unfavourable, and stars 40 minutes west of the meridian. Passy ; November 24, 1824 ; Seven-feet Equatorial. 9th and 12th magnitudes. Position = 75° 51' «;> I 5 Obs. | Diff. = 6° 32'. Excessively difficult. No observations of distance can be procured. Night not good, and the observa- tions made, the stars being ij hour west of the meridian. Passy ; August 23, 1825 ; Seven-feet Equatorial. 9th and 10th, or 11th magnitudes. Position = 74^ z sp\s Obs. DifF. = 1° 52' } E^cessivelv difficult Distance = io".245 | 5 Obs. DifF. = o".s29 5 excessively ditticult. Stars extremely faint, and under a slight illumination become invisible. Mean Result. Position 73° 49' sp(i5 Obs.); Epoch 1825.13 ; Distance io".256 (10 Obs.) ; Epoch 1825.24. No. D CCLIX. R. A. 20^^ 28- ; Decl. 14° 8' N. Struve, 686 ; IV. 92. Triple ; A of the 9th, B of the 9^, and C of the 10th mag- nitudes. Measures of A. B. Passy ; October 9, 1824 ; Seven-feet Equatorial. Position 2520° 25' sf\ 5 Obs. Distance =: 25".272 j 5 Obs. DiflF. = 1° 34' ^ Diff.= i".8o3i Passy ; November 9, 1824 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 19° 31' «/ 1 5 Obs. I DifF. = i° 20' ) ^ , Distance = z^-'.S^s I 5 Obs. | DifF. = i".o34 5 ^^^^ ^^^y* 262 Mr, South' s observations of the apparent distances No. DCCLIX. continued. ^^yf Measures of A C. .j^; ,, Passy; October 9, 1824; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 53° ii' sp I 5 Obs. 1 DiiF. = 1° 3' ) Distance= 54".! 36 | 5 Obs. | DifF. = i".o82 5 * * * Passy ; October 14, 1824 ; Seven-feet Equatorial. 9th and 10th magnitudes. ^^- oi ::. Position =: 52" 40' «j> Distance = 54".203 5 Obs. I DifF. = 1° 41' > g^^ 5 Obs. I DifF. = 1 ".8035^°^^"- My friend Mr. Troughton, being on a visit to me at Passy, was so kind as to take the following observation this even- ing, October 14, 1824. Distance = 54".5s8 | 5 Obs. | DifF. = i'.2g\. Mr. Troughton. Mean Result. of AB. Position 19° 5S' sf; Distance 25".o83 ; Epoch 1824.81. of AC. Position 52'* 55' 5i> (10 Obs.); Distance 54".299 (15 Obs.); '■'■'' Epoch 1824.78. The position of A B here given differs only 1° 31' from what it was in 1783, and the distance only i".2. (H.) No. DCCLX. R. A. 20^^ 34'° ; Decl. 12° 6f N. Struve, 690 ; Hist. Gael. 106. Double ; equal ; each of the 9th magnitude. Blackman-street ; July 1.3, 1824 ; Five-feet Equatorial. Position = 3° 13' w/or sp I 5 Obs. DifF. = 1° 24' ) ^.^ , Distance = 9".og6 ] 5 Obs. DifF. = o".632 ] -Difficult. These stars do not bear a good illumination. Passy ; November 6, 1824 ; Seven-feet Equatorial. Equal ; each of the 1 0th magnitude. Position =: 2° 47' sp or nf Distance = 9".293 DifF. = 1° 37' ) _.„ , DifF. = o".937J^^ffic"lt- 5 Obs. 5 Obs. Observed when 50 minutes west of the meridian ; night very hazy. Mean Result. Position 3° o' nf or sp ; Distance 9".i94 ; Epoch 1824.68. and positions of 458 double and triple stars y &c. 263 No. DCCLXI. R. A. 20^ 37"^ ; Decl. 23° 17' N. Nova ; Double ; 10th and lo^ magnitudes. Passy; September 1, 1825; Seven-feet Equatorial. Position == 63° 13' np I 5 Obs. Distance r= i"'93S — I * Obs. ' ^ ^ > Excessively difficult. Stars extremely unsteady and ill defined. The results are of doubtful accuracy. Passy ; September 15, 1825 ; Seven-feet Equatorial. lOth and 10^ magnitudes. Position r: 60° 39' np I 5 Obs." I DifF. = 4° 10' ) ^ . , ..-e ,^ Distance = 2". 072 \ 5 Obs. | Diff. = J".288 j Excessively difficult. Observed with 181. Stars tolerably steady. Mean Result. Position 61° 56' np (lo Obs.); Distance 2^049 (6 Obs.) ; Epocb 1825.69. No. DCCLXII. R. A. 20*' 37" ; Decl. 30° 4' N. 52 Cygni ; Struve, 691 ; II. 25. Double ; 6th and 10th magnitudes; small, blue. Passy ; October 2, 1824 ; Seven-feet Equatorial. Diif! = o".6oi ( Extremely difficult. Position =33° 26' nf\ 5 Obs. Distance = 7". 127 | 5 Obs. Several stars in the field. One double, of the 4th or 5th class, follows 52 Cygni a few seconds of time; but the attempt to measure it has been unsuccessful: it will not bear the slightest illumination. Night very fine. Passy ; August 23, 1825 ; Seven-feet Equatorial. 8th and 10th, or 1 1th magnitudes. Position = 32° 1' nf 6 Obs. I DifF. = 1° cc' ) „ , , ,._ ,^ Distance = 7".278 5 Obs. j Diff. = o".432 j Extremely difficult. Stars on the meridian, and very steady ; the small one is light blue, and bears but a very feeble illumination. 264 Mr. South' s observations of the apparent distances No. DCCLXII. continued. Mean Result. Position 32° 40' nf (11 Obs.); Distance 7".202 (10 Obs.); Epoch ] 825.19. In 1781 this star was measured at 31° 3' nf. It therefore appears liable to no change of position. The distance is variously stated at 2^, 3, and 4 diameters, according to atmospheric circumstances, power, &c. (H.) No. DCCLXIir. R. A. 20^ 38"; Decl. 18° 51' S. Struve, 693 ; Hist. C^el. 1 77. Double ; 7^ and 8th magnitudes. Passy ; September 23, 1824 ; Seven-feet Equatorial. Position z= 25° 23' np c Obs. l Diff. ^ i** 3' ) m 1 v, ^ j Distance = iS".785 5 Obs. \ DifF. = o".2so \ tolerably steady. Observed on the meridian. Passy ; November 6, 1824 ; Seven-feet Equatorial. 8i and 9th magnitudes. Position = 24° 50' np 5 Obs. I DifF. = 3° c' ) « .u jx-az 1 Distance = iG'.yii 5 Obs. | DifF. = '".g+rf ^^^her difficult. Night very hazy ; stars faint. Mean Result. Position 25** 6* np\ Distance 16". 749 ; Epoch 1824.78. No. bcCLXIV. R. A. 20^ 38'" ; Decl. 15° 14' N. Struve, 692 ; 11. 66. Double; 8|- and 9th magnitudes. Passy ; September 17, 1824 ; Seven-feet Equatorial. Position = 83° 47' nf \ 5 Obs. 1 DifF. = 2° 4'. Rather difficult. Passy ; September 23, 1 824 ; Seven-feet Equatorial. 9th and 10th magnitudes. -fyci Position 83° 47' np \ 5 Obs. j DifF. = 0° 42'. Very difficult. Night very hazy. and positions of^s^ double and triple stars y ^c. 265 No. DCCLXIV. continued. Passy ; September 29, 1824 ; Seven-feet Equatorial. 9th and 9^ magnitudes. Position = 87°i9'np|5 0bs. ^S.-z^z' ^ Catisfactorv Distance = 5".58o j 5 Obs. Diff. = o'.793 ] Satisfactory. Observed when i\ hour west of the meridian; stars most admirably defined, are remarkably steady, and bear a very good illumination. Night unusually fine. Passy ; August 14, 1825 ; Seven-feet Equatorial. 9th and 9f magnitudes. Diff: = i''.ig2l^^'*y^^®*^^^'' Position =: 85° 1 2' np Distance r= ^".zzz Distance rz ^'.jSo 5 Obs. 5 Obs. 5 Obs. 923 DiiF. = o".649. Difficult. Night hazy, but less so when the 2nd set of distances was procured. Passy ; August 16, 1825 ; Seven -feet Equatorial. 8| and 9th magnitudes. . Position = 84° 48' np 5 Obs. I Diff. = 1° 28' ) ^ , Distance = 4".722 5 Obs. I DifF. =: 0^649 ( ^^"^ '^^^"^y* Stars bear a very good illumination. Night favourable ; observations satisfactory. Passy; August 23, 1825 ; Seven-feet Equatorial. 9th and 91 magnitudes. Distance = 4". 609 | 5 Obs. , Diff. = o''.456. Tolerably steady. The distance, 5". 580, taken September 29, 1824, is probably large ; still as the observations were made under favourable circumstances, I cannot reconcile myself to their rejection. Mean Result. Position 84° 59' np {9,5 Obs.) ; Epoch 1825.08 ; Distance 4*. 9 79 (25 Obs.) ; Epoch 1825.40. In 1783.33 the position was found to be 78° 42' np, so that an angle of + 6° 17' seems to have been described since that epoch, or +o**.i28 per annum. This star then should be re-examined after an interval of 10 or 20 years, to ascertain whether the presumed motion be real, or not. (H.) MDCCcxxvi. mm 266 Mr. South' s observations of the apparent distances No. DCCLXV. R. A. 20^ 40™ ; Decl. ss"" 60' N. X Cygni ; Struve, 696', VI. 32. Double ; 5th and 12th magnitudes. Passy ; September 27, 1824 ; Seven-feet Equatorial. Position = 14° 4' «/ I c Obs. I DifF. = o° 35' | ,. _ ,.«. .^ Distance = l'^e".^^^ \ 5 Obs. | DifF. = o-'.el^ \ ^^^ '^^^^^l*' Small star bears but a very feeble illumination. Night fine. Passy ; November 9, 1824 ; Seven-feet Equatorial. 5 th and 12 th magnitudes. The small star is blue, and bears only the slightest illumination; i^ hour west of the meridian when observed. Passy ; August 31, 1825 ; Seven-feet Equatorial. 5 th and 11th, or 12th magnitudes. Position = 14° 53' sf \ c Obs. I Diff. = 0° 56' ^ „ ^ , ,.«. ,^ Distance = 1' z^^sH I 5 Obs. | DifF. = o".529 \ ^^''^^^^y difficult. Mean Result. Position 14° 29' 5/(15 Obs.) ; Distance 1' 25".59o (15 Obs.); Epoch 1825.08. The angle remains within i** 47' what it was in 1781. (H.) No. DCCLXVI. R. A. 20^ 42"^ ; Decl. 5^ 46^ N. Nova; Double ; 9th and 9^ magnitudes. 1 Passy; August 9, 1825 ; Seven-feet Equatorial. Position r= 69° z^ np \ 5 Obs. Diff. := 2° o' } ■p..«. , Distance = 3*.794 | 5 Obs. Diff. = ©".529 ^ ^'"^^"*^- Night hazy ; the stars frequently are very indistinct. Passy ; August 12, 1285 ; Seven-feet Equatorial. 9 th and i)^ magnitudes Position = 69° 38' np Distance =: 4". 202 5 Obs. Diff. = 1° 30' ) ,. ,.n;^ u 5 Obs. Diff. = o".288 \ ^^'y ^'^^''^^- Observed on the meridian ; stars unsteady. Mean Result. Position 69* 31' np ; Distance 3^.998 ; Epoch 1825.61. and positions of 458 double and triple stars y &c. 267 No. DCCLXVII. R. A. 20^ 43" ; Decl. 51° 1/ N. Struve, 698 ; II. 100. Double; 8th and 11th magnitudes. Passy ; August 20, 1825 ; Seven-feet Equatorial. Position = 150 34' nf\ 5 Obs. I Diff. = 2° 28' J Excessively difficult. Distance = 4 .575 | 5 Obs. j DifF. = o".48i > ' Night very favourable ; the small star scarcely bears any illumination. Observed when 35 minutes east of the meridian. Passy ; August 21, 1825 ; Seven-feet Equatorial. 7th and 11th magnitudes. Position =: 15° 25' nf Distance = ^'-907 6 Obs. 5 Obs. Diff! = o°.36o} Excessively difficult. The small star is light blue. Observed on the meridian. A small portion of the object-glass not employed, in consequence of the interference of the observatory timbers. Passy ; September 1, 1825 ; Seven-feet Equatorial. ^'th and 1 1 th magnitudes. Position = 15° 12' ra/ Distance = 3".744 5 Obs. 5 Obs. Diff! = t^.tiz} Excessively difficult. A cloudless sky ; but the stars are extremely unsteady and ill defined; added to these circumstances, a small portion of the object-glass (perhaps one-eighth) is rendered useless by the unfortunate situation of the timbers of the observatory. The observations of position agree w^ell enough ; but it is otherwise with those of distance. The night of August the 20th was much more favourable than either of the nights on which the star was subsequently measured ; and as the mean of the distances procured on those nights will differ but little with that obtained on the 20th, if we take the three sets we shall probably not err much when we give as the Mean Result. Position 15° 24' nf {16 Obs. ) ; Distance 4".409 (15 Obs.) ; Epoch 1825.65. There appears not the least change of position in these stars, the angle here given differing no more than o*' 27' from what it was in 1783. (H.) 268 Mr, South' s observations of the apparent distances No. DCCLXVIII. R. A. 20^ 44" ; Decl. 6« 40' N. Struve, 6q9 ; P. XX. 2^S6' Double ; 8^ and 9th magnitudes ; and do not bear so good an illumination, as their apparent magnitudes would induce one to expect. Blackman-street ; July 15, 1824 ; Five-feet Equatorial. Position = 54«» 45' */ 5 Obs. 1 DifF. = 0° 25' ) Distance = 4o".73i 5 Obs. j Diff. = o".537 3 • • • • Observed when one hour east of the meridian. Same date and Instrument. 8th and 8| magnitudes. Position =: 54° 43' sf I 5 Obs. Distance zz 4o".466 | 5 Obs. DifF. = 1° 14' ) DifF. z= o".727 5 Observed when 10 minutes east of the meridian, and vi^as re^measured this evening inadvertently. Mean Result. Position 54** 44' sf; Distance 4o".598 ; Epoch 1824.54. No. DCCLXIX. R. A. 20^ 50- ; Decl. 15° 47' N. Nova ; Double ; 8th and 8^ magnitudes. Passy ; August 9, 1825 ; Seven»feet Equatorial. Position = 140 8' sj s Obs. Diff. = 0° 46' \ R.^^er difficult. Distance = 14".528 5 Obs. DifF. = o".24o5 Stars extremely unsteady. Night very unfavourable. A star of the 8th magnitude, at some distance in the field, sf. Passy ; August 10, 1825 ; Seven-feet Equatorial. 8^ and 9th magnitudes. Position -iz" S^' sp 5 Obs. I DifF = 1° 10'^ y difficult Distance = 1 5". 1 98 5 Obs. | DifF. = o". 1 68 5 ^ ^^ uimcuit. Small star very faint. Night is become so hazy, that the observations are necessa- rily concluded : not a cloud visible. and positions 0/4,58 douhle and triple stars, &c, 269 No. DCCLXIX. continued. Fa^yj August 12, 1825 ; Seven-feet Equatorial, 8^ and 9th magnitudes. Position = 14° 7'sp I 5 Obs. I DiiF. = 1° 7' ^ ^ difficult Distance = I5".234 | 5 Obs. | DifF. = o".siz S very.mmcult. The small star is light blue, and does not bear a very good illumination. Observed on the meridian, but the stars are very unsteady. . Mean Result. Position 14* 2' 5/) (15 Obs.) ; Distance i4".987 (15 Obs.); Epoch 1825.61. No. D CCLXX. R. A. 20^ 53°' ; Decl. 49° 4>6f N. 280 (Bode) Cygni ; Struve, 703 ; I. 97- Double ; 9th and 95- magnitudes ; small star light blue. Passy ; August 14, 1825 ; Seven feet Equatorial. Position = 58° 9' w/l 5 Obs. I DifF. = 2° 43' | ^ . , j-« t* Distance = i"j6 "^ | 5 Obs. | DifF. = C.^i; [ Extremely difficult. Observed with 181. The night is hazy, and the stars will not bear a higher power. Passy; August 16, 1825 ; Seven-feet Equatorial. 8th and 9 th magnitudes. Position = 60° 13' nf\ c Obs. I DifF. = 3° 11' ) rj^^^^^^UrAi(G^„u Distance = 2".366 "^ \ 5 Obs. | DifF. = o".36o j Extremely difficult. Stars very steady, but will not bear a deeper power than 181. Passy; September 1, 1825 ; Seven-feet EquatoriaL 8^ and Qth magnitudes. Position = 52° 36' nf I 5 Obs. 1 DifF. = 2° 48' ^ gxcessivelv difficult Distance= 2".743 \ 5 Obs. | DifF. = o".432 > Excessively dimcult. Stars very unsteady, and ill defined ; I cannot use a higher power than 181, which is inadequate to separate the stars from each other, so much as I could wish. Passy ; September 5, 1825 ; Seven-feet Equatorial. 8J and 9th magnitudes. Position = 53° 2'nfs Obs. I DifF. = 2° 43' 7 Rvcessivelv difficult Distance = 2".594 | 5 Obs. | DifF. = o".i68 J ^excessively dimcult. Stars ill defined, and very unsteady. Night hazy. Observed with 181: a deeper power was tried, but without success. 270 Mr, South' s observations of the apparent distances No. DCCLXX. continued. Passy ; September 28, 1825 ; Seven-feet Equatorial. 82 and 9th magnitudes. Position =53« 3'nf 1 5 Obs. I DifF. = i° 38' ) g Distance =2". 35 1 \ 5 Obs. | DifF. =o".2i65 Position = 600 54' „/ 5 Obs. I Diff. = 6o ^. j BEAxrroRx. Distance =2 .414 j 5 Obs. | Diff.=o'.i2o ) Position = 62° 3' ra/l 5 Obs. | DifF.= i5° 22'. Mons. Game art. The extreme obscurity of the small star precludes M. Gambart getting any observations of distance. The measures deemed by all observers, excessively difficult; night tolerably favourable, yet a higher power than 181 cannot be employed. The discordance between the position of this double star, as determined on different nights, is enormous ; a circum- stance much to be regretted, as it appears to have under- gone a considerable change since Sir W. Herschel's ob- servations. Mean Result. Position 57° 9' nf ( 36 Obs.) ; Distance 2".449 ( 3o Obs.) ; Epoch 1825.66. The angle of 1783.73 v^as 46° 24' nf. Hence it appears that in the interval of 41 93 years no less an arc than — 10° 45' has been described, giving a mean annual angular motion of — 0^.2564. This star then w^ell merits the attention of future observers. (H.) No. DCCLXXI. R. A. 20^^ bb'^ ; Decl. 6° 30' S. Nova ; Double ; 6th and 1 ith magnitudes ; small, pale blue. Passy ; August 31, 1825 ; Seven-feet Equatorial. Position = 78° o'*p I s Obs. DifF. = 2° 30' 7 Extremely difficult Distance =: 3",224 | 5 Obs. DifF. =0'. 240 3 -^ The small star bears but a very feeble illumination. Measures must not be consi- dered standard : the night is become very bad. Observed on the meridian. and positions of ^^S double and triple stars, &c. 271 No. DCCLXXI. continued. Passy ; September 1, 1825 ; Seven-feet Equatorial. 6th and 1 1th magnitudes. Position = 7»° 59' «p 5 Obs. I DifF.= 3° 30' 1 Excessively difficult Distance = 3".43 1 5 Obs. | Diff. = o".3 1 2 § excessively aimcuit. Stars very ill defined, and also unsteady ; results therefore deserving but little confidence ; indeed 1 feel so little satisfied with them, that even should they accord with the former observations, I would still prefer another series, taken under more favourable circumstances. On the meridian at the time of observation. Passy ; September 2, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position =s: yS° z' sp I 5 Obs. Distance = 3".027 j 5 Obs. Diff! = o'^stfij Extremely difficult. Observed on the meridian j stars tolerably steady. Mean Result. Position 78° 20' sp (15 Obs.) ; Distance 3".227 (15 Obs.) ; Epoch 1825,67. No. DCCLXXII. R. A. 20^ 56'' ; Decl. 2° 51' N. Nova ; Double ; 9th and 12th magnitudes. Passy ; August 20, 1 825 ; Seven-feet Equatorial. Position = 59« so' sf I 5 Obs. 1 DifF. = i« 50' ) Kxcesivelv difficult Distance = 3".638 ) 5 Obs. | DifF. = o".3i2 5 ^^cesively dimcult. The small star is pale blue, extremely faint, and scarcely bears the least illu- mination. The results are perhaps a little questionable. Observed when on the meridian ; night tolerably favourable. Passy ; August 21, 1825 ; Seven-feet Equatorial. 9 th and 12th magnitudes. Position = 59° 12' sf 5 Obs. I DifF. = 2° 7' ) gvcessivelv difficult Distance = 3".s89 5 Obs. | DifF. = o".3363 excessively aimcuit. A very slight illumination obliterates the small star. Observations made on the meridian. Mean Result. Position 59** 31' sf; Distance 3".6i3 ; Epoch 1825.64. 272 Mr. South' s observations of the apparent distances No. DCCLXXIII. R. A. 20^57" ; Decl. 34° 44' N. Struve, 704 ; Mayer. Double ; 8th and 9th magnitudes. . Passy ; October 2, 1824 ; Seven-feet Equatorial. Position = 59° 4c' « / I 5 Obs. DifF. = o° 55' ) Distance = 1' 23 .293 | 5 Obs. DifF. = o".6gy j • • • • Several stars in the field; some double, of the 4th and 5th classes; but their extreme faintness renders them unmeasurable with this instrument. Night very fine. , Passy ; November 9, 1824 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 60° 3' nf Distance = i' 23". 206 5 Obs. 5 Obs. S!^- = °°49'jDifiicult. Diff. = 2' .332 5 Night very unfavourable. Mean Result. Position 59° 54' «/; Distance i' 23".249 ; Epoch 1824.80. No. DCCLXXIV. R. A. 20^ 59°^ ; Decl. 33° 26' N. Nova ; Double ; 8th and 9th magnitudes. Passy ; August 9, 1825 ; Seven-feet Equatorial. Position = 47: 25' *P I 5 Obs. DifF. = 1° 51' ^Difficult. Distance = 14 .797 | i Obs. > Night is now become so extremely hazy, that no more observations can be procured. Passy ; August 12, 1825 ; Seven -feet Equatorial. 8th and 8g magnitudes. SI=:°.g;^--<'^ Position = 46° 53' *jp I 5 Obs. Distances: i4''.229 j 5 Obs. Mean Result. Position 47° 9' 5/ (10 Obs.); Distance 14". 3 24 (6 Obs.); Epoch 1825.61. and positions 0/4,58 double and triple stars, &c, 273 No. DCCLXXV. R. A. 21^ 1^ ; Decl. 29° 29' N. Struve, 707 ; II. 97. Double; 6th and 10th magnitudes; small, blue. Passy ; September 24, 1824 ; Seven-feet Equatorial. Position = 46° ci'wo I c Obs. I DifF. =: 3°o' ^ ,, ,.«- , ,^ Distances Wz^ ^ \ 5 Obs. | DifF. = o".889 ^ ^'T^ ^^®^"^*- This star is also double, of the 4th class, an extremely faint star preceding it, at about 70° south. No measures of it can be obtained. The dew is so intolerably troublesome, that I am obliged to discontinue the observations ; and I do it with the greatest reluctance, for the night is unusually fine. Passy ; November 6, 1824 ; Seven-feet Equatorial. 7 th and 10th magnitudes. Position r= 44° 34' np | 5 Obs. Distance zz 3 ".629 J 5 Obs. Eiil^'.yr. I Extremely difficult. .721 ) Night unfavourable ; observations taken when the stars were 50 minutes west of the meridian. Mean Result. Position 45° 12' ;^/>; Distance 3". 5 76; Epoch 1824.70. - The position here assigned, differs only o** 3' from Sir W. Herschel's measure in 1783 ; nor does the distance appear to have sustained any material alteration. (H.) No. DCCLXXVI. R. A. 21^ 2™ ; Decl. 21° 43' N. Struve, 709 ; Bradley. Double ; 6th and 7th magnitudes. Blackman-street ; July 15, 1824 ; Five-feet Equatorial. Position = 3 1° 59' «p I 5 Obs. I DifF. = 2° 55' \ Distances 1 7".663 | 5 Obs. | DiiF. = i".io5 J • • • • Observed when i hour east of the meridian. Passy ; November 3, 1824 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position = 30° 58' np I 5 Obs. I Diff. rr 0° 53' 7 Distance = 1 7".638 | 5 Obs. | Diff. =: i".20* | • • • , Stars two hours west of the meridian, at the time of observation. MDCCCxxvi. n n 274 Mr. South' s observations of the apparent distances No. DCCLXXVI. continued. Passy ; August 14, 1825 ; Seven-feet Equatorial. 8th and 8J magnitudes. Position = 30° 2'np\s Obs. DifF. = i^ 41' \ Unsteady Distance= 1 7^999 | 5 Obs. DifF. = o".48i ] '^"^'^eaay. Night hazy; the stars occasionally very faint; the small one is bluish. Passy; September 5, 1825 ; Seven-feet Equatorial. 8th and 8^ magnitudes. Position = 30« 35' np I 5 Obs. I Diff. = 0° 30' ) y unsteady Distance z= i7".oS4 | 5 Obs. j DifF. = o".962 5 ^^^ unsteafly. Night extremely hazy. Passy ; September 9, 1825 ; Seven-feet Equatorial. 8^ and 9th magnitudes. Distance =: i8".o7i | 5 Obs. J Diff. = i".oio. Tolerably steady. The night is very hazy, and the small star at times extremely faint. All the observations of this double star taken this year, 1825, were the result of inadvertence ; I was not aware that the star had been observed in 1824. Mean Result. Position 30° 6s' np (20 Obs.); Epoch 1825.17 ; Distance 17".685 (25 Obs.); Epoch 1825.27. No. DCCLXXVII. R. A. 21^^ 2- ; Decl. 61° 26' N. Struve, 708 ; 1789.213. Double ; 9th and 9^ magnitudes. Blackman-street ; July 10, 1824 ; Five-feet Equatorial. Position r= 29** 53' np \ 5 Obs. | Diff. = 3° 32'. Extremely difficult. Observed when 2 hours east of the meridian. Passy; November 16, 1824; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 35° 37' no 5 Obs. I Diff. = 0° 23' ) ^ ^ _ , ..«. ,^ Distance= 7 .002 ^ 5 Obs. | Diff. = o".9i3 ] E^t'-emely difficult. and positions 0/4,^8 double and triple stars, &c. 275 No. DCCLXXVII. continued. ^ Passy ; August 23, 1825 ; Seven-feet Equatorial. 9th and 91 magnitudes. Position = 32<> 3' n o I c Obs. I Diff. = 3° 31' ) „ ,.^ ,. Mean Result. Position 32° 31' np (15 Obs.) ; Epoch 1825.01 ; Distance 6".825 (lo Obs.); Epoch 1825.25. No. DCCLXXVIII. R. A. 2ii» 2™ ; Decl. 8° 50' N. Nova ; Double ; equal ; each 9th or 10th magnitudes ; both bluish. Passy; August 16, 1825; Seven-feet Equatorial. Position = 6° I'sp orn/ I c Obs. I Diff. = i°27' ) „ • i j-a: i. Distance = 2". 938 "^ | 5 Obs. | Diff. = o". 192 j Excessively difficult. Stars tolerably steady, but are very faint. Night hazy. Passy ; October 7, 1825 ; Seven-feet Equatorial. Equal; each of the 10th magnitude. Position := 5° 45' sp or nf\ 5 Obs. | Diff. = 1° 58'. Excessively difficult. Measures of distance impracticable ; neither star will bear the least illumination. Night tolerably favourable. Passy; October 8, 1825 ; Seven-feet Equatorial. Equal ; each of the Qth magnitude. Position = s; S^'sp or nf 5 Obs. Diff. = 4^ 48' | Excessively difficult. Distance = 3 .236 5 Obs. Diff. = 0'. 120 3 ^ Night is become so hazy, that Captain Beaufort cannot procure any observations. Mean Result. Position 5° 55' sp or nf (15 Obs.) ; Epoch 1825.75 ; Distance 3".o87 (10 Obs.) ; Epoch 1825.74. 27^ Mr. South's observations of the apparent distances No. DCCLXXIX. R. A. 21^ 2°» ; Decl. 38° 1' N. Struve, 710. Double ; 8th and loth magnitudes ; small, blue. Passy ; October 2, 1824 ; Seven-feet Equatorial. Position = 79° 23' nf c Obs. DifF. = i° o' ) ,. ,.n: ,, Distance = i'^54":234 5 Obs. DiiF. r: o'^6oi J ^"^^ ^^^^"^*- Several stars in the field ; some double of the 3rd and 4th classes ; but all too faint for measures. Passy; November 21, 1824; Seven-feet Equatorial. 8th and II th magnitudes. Position = 79° 7' «/ Is Obs. I DifF. = !<> 43' ") „ ^ , ,. _ . Distance= I' 56".367 | 5 Obs. | Diff. = ,".75% J Extremely difficult. Observed when 70 minutes west of the meridian. Jt Passy ; October 8, 1825 ; Seven -feet Equatorial. 8th and 1 1th, or 12th magnitudes. Distances 1' S3".753 | 5 Obs. | DifF. = i"-^7S' Excessively difficult. Night hazy. Mean Result. Position 79° 15' nf {10 Obs.); Epoch 1824.81 ; Distance 1' 54".785 (15 Obs.); Epoch 1825.13. No. DCCLXXX. R. A. 21^ 2- ; Decl. 19° 16' N. Nova ; Double ; equal ; each 9th magnitude. Passy : August 14, 1825 ; Seven-feet Equatorial. Position = C7<* 14' nf or sp I 5 Obs. 1 DifF. = 4° 21' 7 -n-a: ^^ Distance = 3'\4»9 Is Obs. DifF. = ^".360 j ^^^<^"1*- Night very hazy, and stars unsteady. Passy ; September 5, 1825 ; Seven-feet Equatorial. Equal ; each of the Qth magnitude. Position = 59° 8' nf or sp Distance = 2". 748 5 Obs. 5 Obs. S-ff- = '^3' 1 Very difficult. DifF. = 0.312) ^ Night hazy ; stars unsteady, and bear but a very feeble illumination. and positions of 4*58 double and triple stars ^ &c, 277 ^^ No. DCCLXXX. continued. .^_j irr . . Passy ; September 15, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 580 39' nf\ 5 Obs. 1 Diff. = 2» 34' ] Very difficult. Distance = 2".6$^ \ 5 Obs. | DifF. = o".505 > ^ Stars very steady, but neither of them will bear a good illumination. Mean Result. Position 58° 20' nfoY sp (i 5 Obs.) ; Distance q".9S3 (i5 Obs.) ; Epoch 1825.67. No. DCCLXXXI. R. A. 21'' 4"" ; Decl. 6° 28' N. 19 (Bode) Equulei ; Struve, 712. Double ; 6^ and 7th magnitudes. Blackman-street ; July 13, 1824 ; Five-feet Equatorial. Position = 82° 44' MO 5 Obs. I DifF. = o° 21' ^ n,.- r„^«._ Distance = 3' 4"^3o 5 Obs. | DifF. = i".389 i Satisfactory. Observed by morning twilight, without artificial illumination. Passy ; October 23, 1824 ; Seven-feet Equatorial. 6| and 7 th magnitudes. Position zzSf iz' np\ s Obs. I Diff. = 0° 25' ) Distance = 3'2".8o9 | 5 Obs. j Diff. = i".o82> • • • • » Passy ; August 23, 1825 ; Seven-feet Equatorial. 7th and 7J magnitudes. Distance == 3' 2'.783 | 5 Obs. | Diff. = o".4o8. Very steady. Mean Result, Position 82** 58' np (lo Obs.) ; Epoch 1824.77 ; Distance 3' 3".24i (15 Obs) ; Epoch 1824.99- 278 ^^' South's observations of the apparent distances No. DCCLXXXII. R. A. 21^ 6» ; Decl. 9° 17'N. S Equulei ; Struve, 715 ; IV. S7. Double ; 5th and 15th, or 20th magnitudes ; I have often looked for the smalL star in England, but could never detect it. Passy ; October 2, 1824 ; Seven-feet Equatorial. Position = 47° 34' «/ 1 5 Obs. Diff. = i^ 45' ] Excessively difficult. Distance = 25 .492 | 5 Obs. DifF. = 2 .452 ) ' The small star is so extremely faint, that it cannot be seen even in the unillu- minated field, without great attention. The observations were made with 105 ; and although the night is unusually favourable for delicate determinations, yet the measures here given must be received with some suspicion. Passy; October 12, 1825 ; Seven-feet Equatorial. 5th and 15th, or 20th magnitudes. Position = 48° i8'»/| 10 Obs. I DifF. = 4° 20' } Excessively difficult Distance = 26". 77s I 7 Obs. | Diff. = o'.yeg J Excessively amicuit. Observed on the meridian with 157. Night very fine ; the accuracy of the results is perhaps questionable. Mean Result. Position 48° s' nf (15 Obs.); Distance 26''.240 (12 Obs.) ; Epoch 1825.26. This star appears to have sustained a very extraordinary change both in distance and position. Sir W. Herschel's measures are as follows : — 1781.80 (Oct. 22)Pos. 11° 39' nf, Dist. 19". 533- Thus in 43.46 years no less an arc than — 36° 24' has been described, being at the rate of — 0^.838 per annum, and a change of distance to the amount of -[- Gf'.yoj, or + o".i54 per annum. An observation in a 20-feet sweep in 1785 confirms the fact of the angle made by the two stars being then small. "^Equulei, double, very unequal, a few degrees nf. S.r." and positions of 4t5^ double and triple stars , &c. 279 No. DCCLXXXII. continued. The star is a remarkable one ; and from its magnitude and situation in the heavens, not to be confounded with any other. The proper motions assigned to this star in Piazzi's Cata- logue, account satisfactorily for the change observed. They are respectively + o".o8 in R. A. and — 0^.29 in declination. These motions, in 44 years, would carry the large star 3". 5 to the following, and 12". 8 to the south side of its place in 1781, or, in a direction, making an angle of 74° 5/ with the parallel. Supposing then the small star fixed, the present angle of position and distance should be 47** nf and 22". 5 instead of 48° s' and 26''.24 which observation makes them. If we consider the uncertainty which necessarily hangs about the earlier distance, depending as it does on a single mea- sure, and from the extreme minuteness of the small star, liable easily to an error of 2 or 3", it will be allowed that a more satisfactory verification of the proper motion of the one star, and the comparative fixity of the other, could hardly have been looked for. This, among other similar instances, will serve to show the advantage which may be taken of the measures of double stars in all researches relating to the proper motions of the stars. This star appears to be a fit object for the investigation of parallax, (H.) . No. DCCLXXXIII. R. A. 21^ 7" ; Decl. 8° 23' S. Struve, 716 ; Hist. Gael. 197. Double ; 9th and 9 J magnitudes. Passy ; September 23, 1824 ; Seven-feet Equatorial. Distance = 5".i67 | 5 Obs. j Diff. = ©".889. Extremely difficult. These stars scarcely bear any illumination. 280 Mr. South's observations of the apparent distances No. D CCLXXXIII. continued. Passy ; November 21, 1824 ; Seven-feet Equatorial. 9\ and 10th magnitudes. - -. J B . ??n'^^" == 'f.V '^ 5 ?t' I n-^' " '° r' \ Extremely difficult. -vjjii-^ d 1 Distance = 4". 8o I 5 Obs. | Diff. = o".Siy) ^ Observed when 50 minutes west of the meridian ; the stars become invisible under a very slight illumination. Passy ; September 2, 1825 ; Seven-feet Equatorial. 9^ and 10th magnitudes. Position = 820 6' sf Distance = 4".'^4-2 5 Obs. 5 Obs. Ei^: = ^°.;';;}verystea.,. These stars bear neither illumination, nor magnifying power ; and although the night is very fine, the results are a little suspicious. .mDriM>- > Mean Result. V Position 82° 22' sf (10 Obs.); Epoch 1825.28 ; Distance 4".837 ; (15 Obs.); Epoch 1825.10. No. DCCLXXXIV. R. A. 2i»> ii'" ; Dec!. 8' 48' N. ;i}o(T! 'ijqo'KT -Nova^j^^friiyy yjojosr Double ; 9th and 10th, or 11th magnitudes. ,j, iiili.i; Passy ; September 15, 1825 ; Seven-feet Equatorial. Position = 84° so' ^P I 5 Obs. I Diff. = 1° 20' 7 Excessively difficult. Distance =: 2". 394 | 5 Obs. | Dirt, zi o".24o 3 ' Stars steady, but the small one bears only the most feeble illumination. Passy ; October 8, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. Position = 84° I3'«;) I 5 Obs. Diff. = 2° c^ ) „ Distance = 2".85i | 5 Obs. Diff. = o".i6%]^^^'^^' Position = 85° 35' .;, 5 Obs. I Diff = 2° 50' ) ^ BEAUFoax Distance = 2".890 | 5 Obs. | Diff. = o".24o5 ^^^^' ^^^^FoaT. Observations considered excessively difficult, by both observers. Mean Result. Position 84° 53' sp (15 Obs.); Distance 2".642 (15 Obs.) ; Epoch 1825.74. and positions 0/4,58 double and triple stars, &c. 281 No. DCCLXXXV. R. A. 2i»» 13' ; Decl. 52° 15' N. Struve, 718. Double ; equal ; each of the 9th magnitude. Blackman-Street ; July 10, 1824; Five-feet Equatorial. Position =r zf zi'sf or nj> I 5 Obs. I Diff. = 3^ 30' J Rather difficult. Distance = 6 '.8 18 | 5 Obs. | Diff. = o .885 5 The star i| hour east of the meridian, when the observations of it were procured. Passy ; August 23, 1825 ; Seven-feet Equatorial. Equal ; each 9^ magnitude. Position = 25°43'*/ornp I 5 Obs. I Diff. = 2° 10') r>;fl;/.„u Distance = sl^l] I 5 Obs. | Diff. = d'.j^.s ] ^^^^1*' The measures of this double star would be very easy, but for the unfortunate interference of the observatory timbers. Mean Result. Position 36° 33' s for np; Distance 6". 641 ; Epoch 1825.08. No. DCCLXXXVI. R. A. si** 13° ; Decl. 52° 19' N. 327 (Bode) Cygni ; H. C. 301 ; Struve, 717. Double ; 7th and 1 ith magnitudes. Blackman-Street ; July 10, 1824 ; Five-feet Equatorial. Position = 32° 8' »/) Distance = 49". 5 80 5 Obs. 5 Obs. Diff. Diff, ' _ „ 2"^ > Extremely difficult. The small star is decidedly blue, and bears but the slightest illumination. Observed when if hour east of the meridian. Passy ; September 2, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Position =32** 36' «j? Distance = 48".! II 5 Obs. 5 Obs. n-ff='° ^'11 Very difficult. Diff. = o .505 ) ' Stars remarkably steady ; observations satisfiictory. Passy ; September 4, 1825 ; Seven-feet Equatorial. 8th and 11th, or 12th magnitudes. Distance = 48".526 | 5 Obs. | Diff. = ©".793. Extremely difficult. Mean Result, Position 32? 22' np (lo Obs.); Epoch 1824.61 ; Distance 48".739 (i5 Obs.) ; Epoch 1824.97. MDCCCXXVI. 0 0 282 Mr. South' s observations of the apparent distances No. DCCLXXXVII. R. A. 2i»^ 14™ ; Decl. 19^ 3' N. 1 Pegasi ; Struve, 719 ; V. 20. Double ; 5th and 9th magnitudes ; small, blue, and bears a very tolerable illumination. Passy ; September 17, 1824 ; Seven-feet Equatorial. Position = 38° 52' w j» 1 5 Obs. 1 DifF. = 2° 54' \ Distance = 37".55o j 5 Obs. | Diff. = o".84i > * ' ' * . Passy ; November 9, 1824 ; Seven-feet Equatorial. 5th and 10th magnitudes. Night very unfavourable. Passy ; August 31, 1825 ; Seven-feet Equatorial. 5th and 11th, or 12th magnitudes. Position =400 40' no I c Obs, I DifF. = \^ %' \ -o • i j-n: i^ Distance = l6".837 | 5 Obs. \ DifF. = ,".010} E^<^essively difficult. Passy; September 1, 1825 ; Seven-feet Equatorial. 5th and 1 1 th magnitudes. Position = 40" 58' no .5 Obs. I DifF. = 0° 50' ) tj . , ,.«. ,^ Distance = ]6".99i 5 Obs. | Diff. = i".i43 f ^^^""^^^y ^^^^"^*- Night cloudless ; but the stars are ill defined, and are extremely unsteady. Mean Result. Position 40° ii' np (20 Obs.) ; Distance 36".86i (20 Obs.); Epoch 1825.22. In 1781 the position was 38° 19' np ; the distance 4o".75o " pretty exact." The distance is too large to be fully relied on ; but the agreement of positions within 2° shows that the star has undergone no notable change. ( H. ) and positions 0/4*58 double and triple stars, Gfr. 283 No. DCCLXXXVIII. R. A. 21^ 14' ; Decl. 7° 20' S. Struve, 720; Hist. Csel. 197. Double ; 7th and 7|- magnitudes. Passy; September 23, 1824 ; Seven-feet Equatorial. Position = 6° 42' nf Distance = ^^".$7^ 5 Obs. S Obs. DifF. = o" 30' I DifF. =o".769> Passy ; November 6, 1824 ; Seven-feet Equatorial. 8| and 9th magnitudes. Position =6° 19' nf 5 Obs. DifF. =: .• ,6' J pyB^„,^_ Distance = 36".99i 5 Obs. DiiF. = i".8o3 j Stars faint. Night very foggy. Mean Result. Position 6** 30' w/; Distance 36". 784; Epoch 1824.78. No. DCCLXXXIX. R. A. 2i»» 18-; Decl. 12° 56* N. Nova ; Double ; 8th and 10th ipagnitudes; small star is pale blue, and bears scarcely any illumination. Passy ; August 21, 1825 ; Seven-feet Equatorial. Position = 55« 42' i>p 5 Obs. Diff. = 4° 10' ) ^ . , ,.-. . Distance = 3".43i 6 Ols. DifF. = o".6oi } Excessively difficult. Observed on the meridian. Passy; September 15, 1825 ; Seven-feet Equatorial. Sth and 10th magnitudes. Position = 57° 16' sp \ 5 Obs. I Diff. = 1° o' > ^ • 1 j-a 1. Distance = 3".539 I 5 Obs. | Diff. = o".i2o J Excessively difficult. The small star is light blue, and bears hardly any illumination. Night tolerably favourable. Mean Result. Position s^ 29' sp ( 10 Obs.) ; Distance 3".48o (11 Obs.); Epoch 1825.67. 284 Mr. South's observations of the apparent distances No. DCCXC. R. A. 21^ 18"; Decl. 35° 33' N. 69 Cygni ; Struve, 722 ; V. 44. Double ; 6th and 12th magnitudes. Passy ; October 2, 1824 ; Seven-feet Equatorial. Position = 1 1° 40' *;) cObs. DifF. = o° ^z'rl _ ., , ,._. . Distance =:4o".504 ? Obs. DifF. = i".899 J ^^""^^^^^ ^^^^^^^' Night very favourable. Passy ; November 21, 1824 ; Seven-feet Equatorial. 6th and 12th, or 15th magnitudes. Position = 11° 57' «p I 5 Obs. j DifF. = 1° 44'. Excessively difficult. Observations of distance cannot be procured. .,.. Passy ; October 12, 1825 ; Seven-feet Equatorial. 8 th and 12th, or 13th magnitudes. Position = 10° 30' $p I 5 Obs. 1 DifF. = 1° 5' i _. • , .•«• 1. Distance = 4o".io7 | 5 Obs. | Diff. = o".889i Excessively difficult. Observed on the meridian with 157. Night fine. Mean Result, Position 11** 22' sp (15 Obs.); Epoch 1825.14 ; Distance 4o".so5 (10 Obs.); Epoch 1825.27. Sir W. Herschel gives no measures of this star. (H.) No. DCCXCI. R. A. 21^ 20" ; Decl. 10° 19' N. Nova ; i[rr.mih vi9^<^^^^^ ' ^T ^^^ 9th magnitudes. Passy ; August 31, 1825 ; Seven-feet Equatorial. Position = 67° 6' no I c Obs. I DifF. = 2^42' ") ^j . , ,.«- ,^ Distances i".46o± | i Obs. j 1_ | Excessively difficult. Observed with 327, which is not sufficient to separate the stars sufficiently from each other. Night is suddenly become very bad, and these measures must only be regarded as approximations. and positions 0/4,58 double and triple stars, &c. 28% No. DCCXCI. continued. Passy ; September 10, 1825 ; Seven-feet EqiiatoriAl. 8j and 9th magnitudes. Position = 6f 4' ./ 5 Obs. I DifF. = 3° 28' | Excessively difficult Distance = i". 142 ± 5 Obs. | Diff. = o".240 > excessively mmcuit. These stars are of a bluish colour, and neither bear a good illumination, nor a high magnifying power. Observed with 327, which is more than they well bear : 1 8 1 does not separate their discs, although the night is hazy. The results are probably a little suspicious. Mean Result. Position 68° 5' np or 5/(10 Obs.) ; Distance i".i95 ± (6 Obs.) ; Epoch 1825.68. No. DCCXCII. R. A. 21^ 24" ; Decl. 33° 2' N. Nova ; Double ; equal ; each of the 9- magnitude. Passy ; August 20, 1825 ; Seven-feet Equatorial. Position = 79° 21' «o or «/' 6 Obs. Diff. = i° 15' ) „ ^ , ,.^ , Distance = 4".474 5 Obs. Diff. = o".432i ^^*''^"'^^y ^^®^^^*' Stars steady ; night tolerably favourable. Passy ; September 4, 1825 ; Seven-feet Equatorial. lOth and 10| magnitudes. Position z= 79" 26' nf I 5 Obs. Distance = 4". 169 j 5 Obs. Diff! = o".4S6 } ^^^^^^^^y difficult. Observed on the meridian j night very hazy. ,: ; Mean ResultaAiji^ •. Position 79° 23'^/ or nf {11 Obs.) ; Distance 4". 321 (lo Obs.) Epoch 1825.65. No. DCCXCIII. R. A. 2i»» 25°^ ; Decl. 19° 56' N. Nova ; Double ; 9th and 9^ magnitudes. Passy; August 21, 1825; Seven-feet Equatorial. Position = 40° S7' np\ S Obs. | Diff. = 2° 14'. Very difficult. Observed on the meridian. 386 Mr, South's observations of the apparent distances No. DCCXCIII. continued. Passy ; September 5, 1825 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 41° 48' np I c Obs. I DifF. z= i® 20' ^ ,, ,.«: ,^ Distance = l".S79 I S Obs. | DifF. = o". 120 \ ^^^ ^^^^"^'- • ifi^d I Night hazy ; stars on the meridian, but unsteady. Passy ; October 11, 1825 ; Seven-feet Equatorial. 9th and 9J magnitudes. ;( Position = 42" 14' «p I c Obs. | DifF. = 2° 2' ) ,, . , ..^ . Distance = z\s^^ I 5 Obs. | DifF. = o".i68 j Excessively difficult. Both stars are bluish, and bear scarcely any illumination. Night foggy. Mean Result. Position 41° 40' np {is Obs.) ; Epoch 1825.70 ; Distance s". 580 (10 Obs.); Epoch 1825.73. No. DCCXCIV. R. A. 21^ 31™ ; Decl. 35° 35' N. Nova ; Double ; 9th and 12th, or 15th magnitudes. Passy ; September 2, 1825 ; Seven -feet Equatorial. Position = 71° 51' sf\ c Obs. I DifF. = 3° 15' ) r, • , j-n: 1 Distance = %",i\g | 5 Obs. | DifF. = o".673 J Excessively difficult. The small star is so extremely faint, that it cannot be seen without great atten- tion ; the observations are perhaps a little inaccurate ; but the ^ight is very fine, and the stars are very steady. Position = 72® 15' «/| 5 Obs. Distance =: 8". 206 | 5 Obs. Passy ; September 5, 1825 ; Seven-feet Equatorial. 9\ and 12th, or 1 3th magnitudes. Diff! = i".683 \ Excessively difficult. The small star is only visible by glimpses. Results of suspicious accuracy. Mean Result. Position 72° s' sf; Distance 8^172 ; Epoch 1825.68. and positions of ^^S double and triple stars, &c. 287 No. DCCXCV. R. A. 2i»» ss"" ; Decl. 56° 41' N. Struve, 728 ; P. XXI. 248 ; III. 71. Triple ; A 7th, B 9t, and C of the 9th magnitudes. Measures of A B. Passy ; October 4, 1824 ; Seven-feet Equatorial. Position = 32° 12' sf\ 5 Obs. I DifF. z= 1' 25' ) Distance= i2".22i j 5 Obs. j Diff. = o".i68 5 • • • • Passy; November 16, 1824; Seven-feet Equatorial. 7th and 10th magnitudes. Position = 30° 54' sf I 5 Obs. Distance = i i'.bg^ \ 5 Obs. Diff. = 1° 24' ) ^._ ,^ Diff. =o".889l^'®^"^*- Measures of A C. Passy ; October 4, 1824 ; Seven-feet Equatorial. 7th and 9th magnitudes. Position = 68° 35' np 1 5 Obs. I Diff. = 1° 20' ) Distance = i9".233 | 5 Obs. | Diff. = i".o58 j • • • • Passy; November 16, 1824; Seven-feet Equatorial. 7th and 9th magnitudes. Position = 69° 32' «;> I 5 Obs. I Diff. = 1° 48' ) Distance = 19".543 { 5 Obs. J Diff. = i ".05 8 J • • • • Mean Result. of A. B. Position 31° 33' sf; Distance ii".945; of AC. Position 69° 3^ np; Distance 19". 3 88 ; Epoch 1824.81. These measures compared with those of 1783 give a change of — 3° 51' in angle and +o".3 in distance for the nearer star B, and — 4° 54' and -f o".77 for the more distant one C. If these changes arise from real motions, and be not merely errors of observation, they cannot be accounted for by supposing the stars B and C at rest, and the central star A only in motion. { H. ) 288 Mr. South' s observations of the apparent distances No. DCCXCVI. R. A. 9,1^ 34" ; Decl. 39° 59' N. 76 Cygni ; Struve, 730 ; V. 43. Double; 6th and 10th magnitudes. Passy ; September 29, 1824 ; Seven-feet Equatorial. Position =: 40° 59' sp I 5 Obs. Distances: i' $".6z^ J 5 Obs. Diff. = 1° o' ) T^.^ ,^ Small star very faint. Passy; November 21, 1824 ; Seven-feet Equatorial. 7th and 10th magnitudes. Position 5= 40° 45' sp Distance= 1' 5".667 i^llz': "'J Very difficult. 5 Obs. 5 Obs. DifF. = o".745 J' The small star bears but a very slight illumination. Mean Result. Position 40° ^2* sp; Distance 1' 5". 645 ; Epoch 1824.82. Sir W. Herschel has no measures of this star. (H.) i;i :,ii;/i. tij:,'; J n.i; i' No. DCCXCVH;^'';^ | ^-AJ^i'^'SS^'r^ecl. bgT 46' N. Struve, 729 ; P. XXI. 256 ; III. 72. Double ; 8th and 9th magnitudes. Passy; October 4, 1 824 ; Seven-feet Equatorial. Position = 33® I'ra/I 5 Obs. Distance = 12". 154 j 5 Obs. DifF. = 2° 20' ) j^.ff, . Diff. = o".4o8l^^^^^^*- Passy; November 16, 1824; Seven-feet Equatorial. lOth and 11th magnitudes. Position = 34° 9' »/I 5 Obs. | Diff. = 1® 43'. Excessively difEcult. Night very hazy. Passy; October 11,1825 ; Seven-feet Equatorial, lOth and 11th magnitudes. Distances I2".i47 j 5 Obs. | Diff. = o".6-]i. Extremely difficult, The small star very indistinct. Night foggy. Mean Result. Position 33° 35' nf {10 Obs.) ; Epoch 1824.81 ; Distance 12^.150 (10 Obs.) ; Epoch 1825.37. The angle in 1783 was 31** 35'. The distance 13". li ac- cording to Sir W. Herschel's measures. (H.) and positions of 4fS^ double and triple stars, &c. 289 No. DCCXCVIII. R. A. 2i»» 35"^ ; Decl. 9* 3' N. E Pegasi ; Struve, 731 ; VI. 103. Double ; 3rd and 10th, or lath magnitudes ; small, blue. Blackman-street ; July 15, 1824 ; Five-feet Equatoiial. Position = 52° 41' WJ9 | 5 Obs. | DifF. =z 1" 14. Excessively difficult. Passy; November 6, 1824; Seven-feet Equatorial. 3rd and 10th magnitudes. Position = c^° o' no c Obs. I DifF. = 0° 44' ) ,, ^ , ,.«- ,^ Distance = I' i8'.8o5 5 Obs. | DifF. = 2".404 1 Extremely difficult. Passy; October 12, 1825; Seven-feet Equatorial. 3rd and 10th magnitudes. , Position = 53° 15' np 5 Obs. I DifF. = 1° 12' ) ,^ a-o: 1. Disfance= 2' i8".223 5 Obs. \ DifF. = o".962 J ^^"^ difficult. Observed on the meridian with 157. Night very fine. Mean Result. Position 52° 59' np(i5 Obs.) ; Epoch 1825.05 ; Distance 2' i8".5i4 (10 Obs.); Epoch 1825.31. Comparing the angle of position here assigned with that given by Sir W. Herschel in 1783, we find a difference of only 14'. The distances indeed differ enormously, no less than 47", but this has already been sufficiently spoken of elsewhere. (H. ) No. DCCXCIX. R. A. 21^^ 36'^ ; Decl. 37° 29' N. 79 Cygni ; Struve, 732 ; VI. 57. Double ; 5th and 7th magnitudes. Blackman-street ; July 10, 1824 ; Five-feet Equatorial. Position = 3o«' 36' nf\ 5 Obs. I DifF. = 0° 24' ) Distance = 2' 33".o25 | 5 Obs. J DifF. = i ".579 5 • • • . North preceding the brighter star A, and perhaps a little nearer to it than B, is a starCofthe 12th or 15 th magnitudes : and in the lower part of the field is a doubl« star of the 4th class j equal ; each of the same magnitude as the star C. Position = 30° ± sp or nf, and distance = 4o".o ±. Measures little else than cautious estimations. MDCCCXXVf. pp 290 Mr. South's observations of the apparent distances No. DCCXCIX. continued. Passy ; November 9, 1824 ; Seven-feet Equatorial. 5th and 7tli magnitudes. Position = 30° 42' nf\ 5 Obs. I DifF. = 0° 5' \ „ Distance = 2' 33".325 | 5 Obs. | Diff. = o".6isi ^' Observed when i"* 20' west of the meridian; night unfavourable; no measures of A C can be obtained. Measures of A C. Blackman-street ; July 10, 1824 ; Five-feet Equatorial. 5 th and 12th, or 15th magnitudes. Position = 50° S' np [2 Obs. [ DifF. = 0° 45'. Excessively difficult. The extreme faintness of the small star renders observations of distance impracti- , cable ; but I consider it less than that of A B. Mean Result. of A B. Position 30° 39' nf; Distance 2' 33*. 170 ; Epoch 1824.68. of A C. Position 50° 8' np\ Distance about 2^ minutes ; Epoch 1824.53. Sir W. Herschel has no measures of this star. (H.) No. DCCC. R. A. 21^^ 49™ ; Decl. 6i*» 45' N. Struve, 734; 1789. 213. Triple ; A 6^, B 7th, and C of the 12th magnitudes. Measures of A B. Blackman-street ; July 11, 1824 ; Five-feet Equatorial. Position =5 5° 4'*/ Distance = i' 2".826 Diff. = 0° 59' Kr .J Diff. = o".659p^'*y steady. 5 Obs. 5 Obs. Three hours and a half east of the meridian, at the time of observation ; of A C no measures can be obtained. Note ; There are two sets of triple stars in the field ; the stars here measured are the two brightest. Passy ; November 16, 1824 ; Seven-feet Equatorial. Triple ; but the 3rd star will not bear the least illumination. Position = 55° 39' */ Distance = i' 2". 847 5 Obs. 5 Obs. Diff. = 0° 46' Diff. .=o%6' I ■. =o".8i7 5 Mean Result. of AB. Position 55° 21' j/; Distance i'2".836; Epoch 1824.70. and positions 0/458 double and triple stars ^ C^c. 291 No. DCCCI. R. A. 2i«^ 52-" ; Decl. 12° 51' S. Struve, 737; Hist. Casl. 571. Double ; 9th and 10th magnitudes. Passy ; September 27, 1824 ; Seven-feet Equatorial. Position = 29° 6' sfl c Obs. I DifF. = o«> 35' 7 ,, ..«. ,, Distance = 25".8io | 5 Obs. | DifF. = i".i7S j ^«^y difficult. These stars bear but the most feeble illumination. Night tolerably good. Passy; November 9, 1824; Seven- feet Equatorial. 9^ and 10th magnitudes. Position = 310 2' */ 1 5 Obs. I DifF. = 1° 31' > „ ,.«. ,^ Distance= 2o".096 | 5 Obs. | DiflF. = o'Jiy J ^^''^ difficult. Mean Result. Position so® 4' sf; Distance 2o''.453 ; Epoch 1824.79. No. DCCCII. R. A. Qi^ 53" ; Decl. 17'' 49' S. 29 Aquarii ; Struve, 738. Double ; 8th and 8^ magnitudes. Blackman-street ; July 12,1824: Five-feet Elquatorial. Position = 27° 23' sp | 5 Obs. I DiflF. := i** 30' ) Distance = 4".3 1 7 | 5 Obs. ) Diff. =o".3i6 ) • * • . Passy : November 3, 1824 ; Seven-feet Equatorial. 7^ and 8th magnitudes. Position = 25» 53' sp 5 Obs. Diff. = 2° 21' 7 y unsteady Distance = 4^424 5 Obs. DifF. = o".889 S^^^ unsteady. Observed when 50 minutes west of the meridian. Mean Result. Position 26*^38' sp ; Distance 4".370 ; Epoch 1824.68. 292 Mr. South' s observations of the apparent distances No. DCCCIII. R. A. 21^ 57" ; Decl. 12° 48' N. Nova ; Double ; equal ; each 9th magnitude. Passy ; August 20, 1825 ; Seven-feet Equatorial. 5 Obs. I DifF. = 1° 35' ) o ^, ,.-c 1^ S Obs. I DifF. = o".4o8i ^^^^^' ^^^'"^^- Position = 6° 24' spot nf Distance =: 3 ".244 Stars steady ; night tolerably favourable. Passy ; September 4, 1825 ; Seven-feet Equatorial. Equal ; each of the 9i magnitude. Position = 7** 55' «;? or «/ Distance = 3*.332 5 Obs. 1 DifF. = 2° 9' > ,, ..n; u 5 Obs. I DifF. = o".4b8 J Very difficult. Night hazy j stars at times very faint. Mean Result. Position l"" ^ sp or nf ; Distance 3".288 ; Epoch 1825.65. No. DCCCIV. R. A. 221^ o» ; Decl. 69"" 20' N. Struve, 740; 1789- 218. Double ; y\ and 10th magnitudes. Passy ; October 4, 1824 ; Seven-feet Equatorial. Position = 83° 50' */ 1 5 Obs. j DifF. = o° 48' Extremely difficult. The small star scarcely bears any illumination. Passy ; October 12, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. Position = 83° 36' sf 5 Obs. I Diff. = 0° 55' \ Extremely difficult. Distance = i6".434 5 Obs. | DifF. = o .4565 •' Observed with 157. Night favourable. Passy ; October 13, 1825 ; Seven-feet Equatorial. lOth and 11th magnitudes. Distance = i6".778 ( 5 Obs. | DifF. = o".553. Excessively difficult. Neither star will bear a good illumination. Observed with 157. Mean Result. Position 83° 4s'5^(i5 Obs.) ; Epoch 1825.27 ; Distance i6".6o6 (10 Obs. J ; Epoch 1825.78. and positions oj ^sS double and triple stars, &c, 293 No. DCCCV. R. A. 22^ o™ ; Decl. 36' 45' N. Nova ; Double ; 8^ and 10th magnitudes. Passy ; September 17, 1824 ; Seven-feet Equatorial. Position = 23® 43' nf \ 5 Obs. | Diff. = 4^ o'. Very difficult. The small star bears but a very feeble illumination. Passy ; September 29, 1824 ; Seven-feet Equatorial. 8th and 12th, or 1 5th magnitudes. Position = 22° s'nf I 5 OJs. Diff. = i° 57' } Extremely difficult. Distance = 13' .097 j 5 Obs. Diff.= 0.505) ■' Passy ; November 3, 1824 ; Seven-feet Equatorial. 8th and 1 Ith magnitudes. Position = 22" 13' nj" Distance = i2*.349 5 Obs. 5 Obs. Passy ; September 9, 1825 ; Seven-feet Equatorial. 9th and 11th magnitudes. Position = 22° 39'"/ 1 5 Obs. Diff. = 1- 44' 7 Extremely difficult. Distance ;= 1 2 .877 | 5 Obs. Diff. = 1.178) •' Mean Result. Position 22° 40' w/(2o Obs.) ; Epoch 1825.00; Distance 12".774 (15 Obs.); Epoch 1825.09. No. DCCCVI. R. A. 22'^ 4^" ; Decl. 81° 58' N. 180 (Bode) Cephei ; Struve, 743. Double ; 7|- and 8th magnitudes. Blackman-street ; July 13, 1824 ; Five-feet Equatorial. Position = 12° 36' n/" Distances: I3".c63 Eiffiif'jr?!^^'-"'^'"- f^Obs. 5 Obs. The morning is so far advanced, that artificial illumination of the micrometer wires is unnecessary. Stars steady. Passy ; October 23, 1824 ; Seven-feet Equatorial. 7th and 7^ magnitudes. Position = 11° 26' nf Distance = i4".o7i 5 Obs. 5 Obs. Diff = 1^539} ^"*^^"^'"^^^"- 294 Mr. South' s observations of the apparent distances No. DCCCVI. continued. Passy; September 10^ 1825 ; Seven-feet Equatorial. 7i and 8th magnitudes. Position = 12° 21' nf c Obs. I DifF. = i° ig' \ ^ . r ^ Distance = . 3".s68 J Obs. | DifF. = d'.eig \ Satisfactory. Night hazy j but the stars are steady. Mean Result. Position i2» 8' nf ( 15 Obs. ) ; Distance 13".567 (15 Obs.) ; Epoch 1825.02. No. D CCCVII. R. A. 22I' 6" ; Decl. 28° 41' N. Nova ; Double ; 9th and 9^ magnitudes. Passy ; September 2, 1825 ; Seven-feet Equatorial. Position = 19° 37' 5/1 6 Obs. Distance = 2".o4i | 5 Obs. DifF. = 3° 50' DifF. = o''.240 J Very difficult. Observed with 327, a power just sufficient to separate distinctly the two stars from each other ; but it is unfortunately rather a higher power than the stars yftW bear, although they are very steady, are on the meridian, and the night is favourable. Passy ; September 5, 1825 ; Seven-feet Equatorial. 9th and 9^ magnitudes. Position = 22° 43' sf Distance = i".7i9 Diff.= i" 12' i" 12 j : _ „ * > Extremely difficult. DifF. = o".3i2J 5 Obs. 5 Obs. I attempted to observe this double star with 181, but could not succeed; the measures were procured with 327, which is a power greater than the stars well bear. The stars are unsteady, and the night is hazy. Passy ; September 14, 1825 ; Seven-feet Equatorial. 9th and 9f magnitudes. Position = 21045;*/ I 5 Obs. I Diff. = 3^ 16' \ Excessively difficult. Distance = i .508 j 3 Obs. | DifF. = 0.288 5 ^ The haze is become so considerable, that the stars are no longer visible. Mean Result. Position 21° 15' 5/ (16 Obs.); Distance i".794 (i3 Obs.) ; Epoch 1825.70. and positions 0/4,58 double and triple stars, &c, 295 No. DCCCVIII. R. A. 22'' 16" ; Decl. 21° ^ S. Nova ; Double; 8th and 11th magnitudes. Passy ; October 20, 1825 ; Seven-feet Equatorial. Position = 6J> 35^/1 10 Obs. I Diff. = 4° 10' J Excessively difficult. Distance = o .457 | 5 Obs. [ Difr. = o".288 ) ^ Observed when i| hour west of the meridian ; stars unsteady, night hazy ; the results must be received with caution ; the small star was only visible by glimpses. Unfavourable v^eather has prevented me getting more ob- servations of this double star, although I have endeavoured to observe it every tolerable night, during several weeks. Mean Result. Position 64° 35' ^/(lo Obs.) ; Distance 6".457 (5 Obs.) ; Epoch 1825.80. No. DCCCIX. R. A. 22^ 24" ; Decl. 6' 31* N. Nova; Double ; equal; each of the 10th magnitude. Passy ; September 15, 1825 ; Seven-feet Equatorial. Position = 79° 55' np or sf\s Obs. DifF. = o° 38' ) Ex„„:„.,„ difficult Distance = I2".777 | 5 Obs. DifF. = i".i3o ] ^^""^^"X a»ftcult. Both stars bluish, and bear scarcely any illumination.. Passy; October 11, 1825 ; Seven-feet Equatorial. Equal; each of the 11th magnitude. Position = 79° 28' np or sf\s Obs. I DifF. = 20 44' ) Excessively difficult Distance = 1 3".oi8 | 5 Obs. | DifF. = o".432 J Excessively mmcult. observations deserving but very little confidence; the night is very hazy, and the stars cannot be seen without the greatest attention. Mean Result. Position 79° 41' np or 5/(10 Obs.) ; Distance 12".897 (10 Obs.) ; Epoch 1825.74. 296 Mr. South's observations of the apparent distances No. DCCCX. R. A. 22^ 25"^ ; Decl. 3° 19' N. Struve, 756; Hist. Gael. 108. Double; 8j and 10th magnitudes; the small star is blue, and bears a very tolerable illumiination. Passy ; October 2, 1824 ; Seven-feet Equatorial. 55-=°>5; i Not difficult. Position =55° 27' sf\ 5 Obs Distance = i4".3ii | 5 Obs. DifF.=o".769} Observed on the meridian Passy; November 21, 1824; Seven-feet Equatorial. 9th and 11th magnitudes. Position = 55° 44' sf I 5 Obs. Distance = I3".8i3 | 5 Obs. K-J ~ 5° ^^ \ Excessively difficult. DiiF. = I .010 3 ^ Night unfavourable. Mean Result. Position S6^ 35' 5/; Distance i4".o62 ; Epoch 1824.82. No. DCCCXI. R. A. 22»^ 29" ; Decl. 37° 57' N. Struve, 758. Double ; 9th and 9^ magnitudes ; and bear but a slight illumination. Passy ; October 2, 1824 ; Seven-feet Equatorial. Obs. I DifF. = 0° 47' ) ,. ..fl. 1^ Obs. |Diff. = o".986Jv^^^^^^^^*• Passy ; November 24, 1824 ; Seven -feet Equatorial. lOth and II th magnitudes. Position = 68° 27' np \ 3 Obs. ] DifF. zz i** 10'. Excessively difficult. The night is become so abominably bad, no more observations can be gotten. Passy; September 9, 1825 ; Seven-feet Equatorial. . -p 91 and 10th magnitudes. Position = 67° 6' np Distance = 2o".937 Stars tolerably steady ; but the night is so extremely hazy, that neither of them will scarcely bear any illumination. Mean Result. Position 67° 26' np (13 Obs.); Epoch 1825.11 ; Distance 2i*.i75 (10 Obs.); Epoch 1825.22. Position = 67° g' np Distance = 21 ".41 3 5 2J^' I 55* = ^° ^'^' \ Extremely difficult. 5 Obs. I DifF. = o .505 S ^ and positions 0/4)58 double and triple stars, ^c. 297 No. DCCCXII. R. A. Qsi* 30- ; Decl. is"" 28' S. Struve, 759; Hist. Casl. 181. Double ; 9- and 10th magnitudes, and bear only a very slight illumination. Passy ; September 27, 1824 ; Seven-feet Equatorial. Distance = 6". 547 | 5 Obs. | DifF. = i".o82. Extremely difficult. Passy; November 21, 1824; Seven-feet Equatorial. 9^ and 10th magnitudes. Position =: 56° ^ np I 5 Obs. Distance = S'-ISZ I 5 Obs. Diff! = 1" 082 [ ^^ceedingly difficult. Stars very steady. Night tolerably fine. Passy; September 9, 1825 ; Seven-feet Equatorial. d\ and 10th magnitudes. Position = 57O 28' «/ Distance = 5".732 5 Obs. I DifF. = 1° 23' > ^ ^ , ,.^ ,^ c Obs. DifF. = o".8ii ( Extremely difficult. 5 Obs. I DifF. = o".84i 5 These stars are of a bluish colour, and neither bear illumination nor magnifying power. Mean Result. Position S6° 46' .?/or np ( 10 Obs.); Epoch 1825.29 ; Distance 6".oii (15 Obs.); Epoch 1825.11. No. DCCCXIIl. R. A. 22^ SI'" ; Decl. 38° 7"N. 10 Lacertae ; Struve, 760 ; V. 97. Double ; 6th and 12th magnitudes ; the small star scarcely bears any illumination. Passy ; October 7, 1824 ; Seven-feet Equatorial. Position = 41° 20' nf\ c Obs. \ DifF. = 2° 45' ) ^ , , ,.^ , Distance = i' o".6u | 5 Obs. | DifF. = o'-.g^j \ Extremely difficult. Passy ; December 6, 1824; Seven-feet Equatorial, 6'th and 12th magnitudes. Position s= 42* 34' nf \ 2 Obs. | Diff. =: 0° 7'. Excessively difficult. The night is at present fine, but the small star will not bear even the slightest illumination. No measures of distance can be procured. MDCCCxxvi. q q 298 Mr. South* s observations of the apparent distances No. DCCCXIII. continued. Passy ; October 12, 1825 ; Seven-feet Equatorial. 7th and 13th or 14th magnitudes. Position =40° 48' nf 5 Obs. Diff.= 2° 29' ) ^^^^^^^^^^ difficult. Distance=i o .277 5 Obs. DifF. = o .001 ) ' Observed on the meridian with 157 ; night very fine. Mean Result. Position 41° 19' nf{i2, Obs.); Epoch 1825.16 ; Distance 1' o".444 (10 Obs.); Epoch 1825.27. The present ^ngle differs only 2° 34' from that found in 1783. (H.) No. DCCCXIV. R. A. 22^ ss"* ; Decl. 29° 7' N. Nova; Double ; equal ; each 10th magnitude. Passy ; September 2, 1825 ; Seven-feet Equatorial. Position = 9° ps'np or */| 5 Obs. I DiiF. = 1° 24' ) Excessivelv difficult Distance = i8".425 | 5 Obs. J DifF. = o".769 J excessively dimcult. Stars steady, and on the meridian ; but the results may be a little suspected. Passy ; October 11, 1825 ; Seven-feet Equatorial. 1 Ith and 12th magnitudes. Position = 9° 52' np c Obs, 1 DifF. = 1° 31' 7 ^ • 1 j-a; u Distance = ?8".62o^ 5 Obs. | DifF. = o".529 j Excessively difficult. Night so hazy, and the stars so very indistinct, that great confidence must not be placed in the accuracy of the observations. Mean Result. Position 9° 42' np or sf {10 Obs.) ; Distance i8".522 ; Epoch 1825.72. and positions of 4)^8 double and triple stars, &c, 299 No. DCCCXV. R. A. qq^ 33- ; Decl. 39° ifN. 12 Lacertse; Struve, 761; VI. 121. Double ; 6th and 12th magnitudes. Passy ; October 7, 1824 ; Seven-feet Equatorial. Position = 73° 55' nf\ 5 Obs. j DifF. = 1° 20' ) ^ . , .-a. ,, Distance = i' i2".zs7 \ 5 Obs. | DifF. = i".6ss\ Excessively difficult. The small star will scarcely bear any illumination. Night fine. Passy ; October 12, 1825 ; Seven-feet Equatorial. 6th and 13th, or 14th magnitudes. Position = 73° z'nf \ s Obs. I DifF. = 1° 0' ) _. .,,.«., Distance = i' ii".890 | 5 Obs. | DifF. =0". 793 j ^^*^"^^^^ly^^<^"l^- Observed with 157. Night very fine. Mean Result. Position 7S° 28' nf (10 Obs.) ; Distance 1' 12^.073 (10 Obs.) ; Epoch 1825.27. The angle of 1783 agrees with this within half a degree. (H.) No. DCCCXVI. R. A. 22«^ 35"^ ; Decl. 29° 17'N. V Pegasi ; Struve, 763 ; VI. 21. Double ; 3rd or 4th, and i2tli magnitudes. Passy; October 7, 1824 ; Seven- feet Equatorial. Position = 68° ^B'np] c Obs. 1 Difi^. = o° 14' ) ^ , ..^ Distance = i' 29".38i | 5 Obs. J Diff. = i".S395 ^^*^^"^^v difficult Observed on the meridian. Passy; December 6, 1824 ; Seven-feet Equatorial. 4th and 12th, or 15th magnitudes. Position = 690 4' np I 5 Obs. I Diff. = i«> 12' ) ^ . , ,.^ Distance = i' 3o".266 | 5 Obs. j Diff. = i".683 J Excesssively difficult. The small star scarcely bears the slightest illumination. Mean Result. Position 68** 56^ np; Distance 1' 29".823 ; Epoch 1824.85. Sir W. Herschel gives no measures of this star. (H.) 30 0 Mr. South's observations of the apparent distances No. DCCCXVII. R. A. 22>» 38™ ; Decl. 15° o' S. t' Aquarii ; Struve, 765 ; V. 80. Double ; 6th and 12th magnitudes. Passy ; October 7, 1824 ; Seven-feet Equatorial. Position = 23° zf sf Distance = 30". 838 c Obs. DifF. = 1° 41' ) „ . , ,.<£ u 5 Obs. DifF. = o".86s ] Excessively difficult. The night is remarkably fine. Observations made on the meridian. Passy ; November 21, 1824 ; Seven-feet Equatorial. 7th and l2th magnitudes. Position = 2i*> 36' 5/1 5 Obs. | Diff. = 1° 20'. Excessively difficult. Measures of distance I cannot obtain, yet the night is fine, and the stars are only 15 minutes west of the meridian. Passy ; October 12, 1825 ; Seven-feet Equatorial. 6th and 13th, or 14th magnitudes. Position = zf .8' »/ 5 Obs. j Diff. = z' p' 1 Excessively difficult. Distance = 30 .235 \ 5 Obs. j Diir. = o .697 3 •' Observed on the meridian with 157 ; with 181 I cannot see the small star. • Mean Result. Position 22*' 47' sf (15 Obs.) ; Epoch 1825.15 ; Distance 3o".536 (loObs. ) ; Epoch 1825.27. The measures of 1783 are. Position 19° 54' sf; Distance 35".62. The difference of Position 2° 53' is not material, con- sidering the difficulty of the star ; but a diminution of distance to the extent of 5".i deserves notice, because the microme- trical error of the earlier observations would tend to produce an apparent increase. (H.) and positions of 4}5S double and triple stars, &c. 301 No. DCCCXVIII. R. A. 22^^ 40°^ ; Decl. 14° 33' S. T* Aquarii ; Struve, 767 ; VI. 97. Double ; 5th and 12th magnitudes. Passy; September 29, 1824 ; Seven-feet Equatorial. Position =: 22° 20' np | 5 Obs. | DifF. =: i°4'. Excessively difficult. Passy; November 21, 1824; Seven-feet Equatorial. 7th and 15th magnitudes. Position = 22*^ 28' np \ 5 Obs. | Diff. = 1° 13'. Excessively difficult. Observations of distance impracticable ; night tolerably good. Passy ; October 12, 1825 ; Seven-feet Equatorial. 5th and 14th, or 15th magnitudes. Distance = 2' 13''. 120 j 5 Obs. j Diff. = i''73i. Excessively difficult. Observed on the meridian with 157 ; night very fine. Passy ; October 16, 1825 ; Seven-feet Equatorial. 5th and i2th, or 14th magnitudes. Distance = 2' I3".756 | 5 Obs. | Diff. = i".274. Excessively difficult. Observed with 92, when on the meridian ; with 157 the small star could not be distinguished. Mean Result. Position 22° 24' np (lo Obs.) ; Epoch 1824.81 ; Distance 2' 13".438 (10 Obs.) ; Epoch 1825.78. The angle of 1783 is 18° 30' np, differing 3° 54' from the present, which i& considerable for a star of the 6th. class. (H.) No. DCCCXIX. R. A. 22^^ 41™ ; Decl. 30° 23' N. Nova ; Double ; 9th and 9^ magnitudes ; both bluish. Passy ; September 2, 1825 ; Seven-feet Equatorial. Position = 19° 58' np Distance = 3''.532 c Obs. I Diff. = 2° 52' ) ^7 . , ,.«. ,, 5 Obs. I Diff = o".288 J Excessively difficult. Neither of these stars will bear much illumination. Observations perhaps a little suspicious i yet the night is very fine, and the stars are steady. 302 Mr, South' s observations of the apparent distances No. DCGCXIX. continued. Passy ; September 5, 1825 ; Seven-feet Equatorial. Equal ; each 10th magnitude. Position = 2 j V np or ./ 5 Obs. I Diff. = f 50' \ Excessively difficult. Distance = 3 .893 j 5 Obs. J DiflF. = o .336) ^ Night very hazy. Mean Result. Position so° 31' np or sf; Distance s".jiQ ; Epoch 1825.68. No. DCCCXX. R. A. 22^ 42" ; Decl. 71'' 56' N. Struve, 768; 1789. 219. Double ; 8th and 9th magnitudes. Passy ; October 9, 1824 ; Seven-feet Equatorial. Position = 9° 24' «j9 5 Obs. j Diff. == o° 9' \ Distance = 2' o".848 5 Obs. | Diff. = o".6oi J • • • • A star C of the nth magnitude makes an isosceles triangle with the stars A B here measured; and it is perhaps hardly so much as twice the distance from them, that they are from each other. Position of A C 78*' 30' np (single Observation.) Passy; October 11, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Distance = 2' o*'.942 | 5 Obs. | Diff.r: i''.i54. Very difficult. Observed with 157 ; the small star very indistinct on account of the fog, Passy; October 12, 1825 ; Seven-feet Equatorial. 8th and Sf magnitudes. Position = 9** 21* np | 5 Obs. J Diff. = 0° 40'. .... Mean Result. 1 Position 9° 21' np (10 Obs.); Distance 2' 0^895 (10 Obs.); Epoch 1825.27. and positions 0/4^58 double and triple stars, &c. SOs No. D CCCXXL R. A. 22^ 50™ ; Decl. 26° 49' N. Nova ; Double ; 9th and 11th magnitudes. Passy ; September 9, 1825 ; Seven-feet Equatorial. Position =z 81° o' «/ 1 5 Obs. I Diff. = 2° 48' ) -d ^ , ,.«. , Distance = 7". 074. \ 5 Obs. | Diff. = o" 360 ] Extremely difficult. The small star is blue, and bears only the slightest illumination. Night hazy, but the stars are steady. Passy; October 11, 1825; Seven-feet Equatorial. lOth and 12th magnitudes. Position = 83° 22' nf\ 5 Obs. I Diff. = 3° o' ) ^ • , j-^ , Distance = 6".626 | 5 Obs. | Diff. = o".553 1 Excessively difficult. The night so very hazy, that I have no confidence in the observations of this double star. Mean Result. Position 82° 1 1' nf (10 Obs.) ; Distance 6". 850 (10 Obs.) ; Epoch 1825.73. No. DCCCXXII. R. A. 22»» 57" ; Decl. 32° 26' N. Nova ; Double ; 9th and 9^ magnitudes. Passy; September 2, 1825; Seven-feet Equatorial. Position = 70<> 26' sf I 5 Obs. Diff. ss 1° 5' } Distance = 3".S32 j 5 Obs. Diff. = o".432 5 ^^^ ^^^^^X* These stars bear a tolerable illumination. Night very fine. Passy ; October 11, 1825 ; Seven-feet Equatorial. 10th and 11th magnitudes. Position = 71° 10 sf 5 Obs. I Diff. = 2° 45' 7 _. . , ,._ , Distance = 3".337 5 Obs. | Diff. = o".432 j Excessively difficult. The night so foggy, that the measures are very suspicious. Mean Result. Position 70° 48' 5/(10 Obs.); Distance 3^434 ( lo Obs.) ; Epoch 1825.72. 304 Mr, South' s observations of the apparent distances No. DCCCXXIII. R. A. 23^ s*" ; Decl. 58° 21' N. 2 Cassiopeise ; Struve, 772 ; VI. 65- Double ; 6th and 9th magnitudes. Blackman-street ; July 16, 1824; Five-feet Equatorial. Position = 730 27'*/! 5 Obs. 1 DifF. = o° i6' ) Distances z' 46".397 | 5 Obs. | DifF. = o".885 j • • • • Stars 1 5 hour east of the meridian, at the time of observation. Passy; November 16, 1824; Seven-feet Equatorial. 6th and 9th magnitudes. Position = 73° 14' sf\ 5 Obs. I Diff. =0° 43' ) Distance = 2' 4^6". g6^ \ 5 Obs. | DifF. = o".793 j • • • • Mean Result. Position 73° 20' sf\ Distance 2' 46".683 ; Epoch 1824.70. Sir W. Herschel gives no measures of this star. (H.) No. DCCCXXIV. R. A. 23^ 2- ; Decl. 12° 54' S. Struve, 774; Hist. Casl. 191. Double ; equal ; each of the 9th magnitude. Passy ; October 7, 1824 ; Seven-feet Equatorial. Position =: 1 3° 7' np or sf Distance = 4".o92 5 Obs. I DifF. = 1° 44' ) 5 Obs. I DifF. = o".S77J These stars bear a very tolerable illumination. Night peculiarly favourable. Passy ; November 3, 1824 ; Seven-feet Equatorial. 9th and 9J magnitudes. Position = i2« 15' «p i c Obs. DifF. = 1:° 18' ) ,. ,.«. ,^, Distance = 4".322 "^ ] 5 Obs. DifF. = o".529 \ ^^'y ^'^^"1*' Observed when half an hour west of the meridian. Mean Result. Position i2*>4i'w/> or sj; Distance 4".207; Epoch 1824.80. and positions of 458 double and triple stars, &c. 305 No. DCCCXXV. R. A. 23^ 2- ; Decl. 35° 55' N. Nova ; Double ; 6-J and 7th magnitudes. Passy ; September 9, 1825 ; Seven-feet Equatorial. Position = 50° 2^' np Distance= i' 5".2i3 5 Obs. Diff. = 1° CO' ) ,, , , 5 Obs. DifF. = o".48i 1 ^^^y '^^^^y- Passy ; September 15, 1825 ; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 49° 34' np I 5 Obs. I DifF. = 1° 38' ) q. . Distance = 1' 5".449 | 5 Obs. | DifF. = o".505 j ^^^^^Y' Mean Result, Position 49° 58' np\ Distance i' 5".33i ; Epoch 1825.70. No. DCCCXXVI. R. A. 23^ 5"" ; Decl. 9^^ 52' S. Struve, 775 ; H. C. 191. Triple ; A 7j, B 8th, and C of the 10th magnitudes. Measures of A B. Passy ; October 7, 1824 ; Seven-feet Equatorial. c Obs. I Diff. = 0° 32' ) TT 5 Obs. I Diff. = i".i54J Unsteady. Position =86° 17' sf Distance = 26''. 178 Passy ; November 15, 1824 ; Seven-feet Equatorial. 8th and Sf magnitudes. Position = 86° 3' sf Distance = 26".374 c Obs. Diff. = 1° 35' ) ,, 5 Obs. Diff. = o".384 ] ^^'y unsteady. Measures of A C. Passy ; October 7, 1824 ; Seven-feet Equatorial. 7^ and loth magnitudes. Position = 19° 24' sf 2 Obs. I Diff. = 0° 12' ) ,r j-n: 1 Distance = 2'^37".853 2 Obs. | Diff. = o".9865 ^^^ difficult. The small star is very faint, and bears but very little illumination. MDCccxxvi. rr 3o6 Mr. South' s observations of the apparent distances No. DCCCXXVI. continued. ^ Passy ; November 15, 1824 : Seven-feet Equatorial. 8th and 10th magnitudes. Position = 19° V «/ I c Obs. I DifF. = 0° ci' ) ,?■ a- a: 1. Distance = 2*40^351 | 3 Obs. | Diff. = i".25oi ^^^ ^^^^^l*' Night is become so bad, that no more observations can be procured. Passy ; September 28, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Distance = 2' ^6".^%$ \ 5 Obs. | DifF. = o''.6oi. Extremely difficult. The small star is very obscure. Mean Result. of AB. Position 86° id sf; Distance 26".276 ; Epoch 1824.82. of A C. Position 19° 10' sf(j Obs.); Epoch 1824.82 ; Distance 2' s8".i68 (10 Obs ) ; Epoch 1825.13. No. DCCCXXVII. R. A. 23*" 6- ; Decl. 10° 4' S, ^' Aquarii ; Struve, 776 : IV. 12.* Double ; 5th and 10th magnitudes. Passy ; October 9, 1824 ; Seven-feet Equatorial. Position =: 40® 57' « » I 5 Obs. I DifF. = 0° 42' ) „ * .^ 1 j-rc 1 Distance = 49".630 | 5 Obs. | DifF. = o".793 \ Extremely difficult. The small star scarcely bears the least illumination. Passy ; November 3, 1824 ; Seven-feet Equatorial. 5 th and 10th magnitudes. Position =: 41° 20' no I c Obs. DifF. = 1° 32' ) „ ^ , ..^ ,^ Distance = 5o"-04i I 5 Obs. Diff. = i".iS4i Extremely difficult. Observed when 40 minutes west of the meridian. Mean Result, Position 41' 8' np\ Distance 49".835 ; Epoch 1824.80. • It seems probable, from the total disagreement of the distances, that the star here measured cannot be identical with IV. 1 2, though the angles agree within 3° 34. The distance assigned by Sir W. Herschel is 23" 5"' ** pretty exact." (H.) and positions 0/4,58 double and triple stars, &c. 307 No. DCCCXXVIII. R. A. sl3^ is"; Decl. S4° 29' N. • Nova; Double ; 10th and 12th magnitudes ; scarcely bear the least illumination. Passy ; September 10, 1825 ; Seven-feet Equatorial. Position = 87° 5' sp 5 Obs. I Diff. = 30 57' \ ^ Distance = 5".292 5 Obs. | DifF. = o".673 ] ^^^'' The measures are of such extreme difficulty, that I consider their accuracy open to suspicion. The small star is seen but with the utmost attention. Passy ; September 15, 1825 ; Seven-feet Equatorial. 9th and 12th, or 14th magnitudes. Position = 85° 22' sp I 5 Obs. Diff. = 2° 3' \ verv steadv Distance = 4".943 | 5 Obs. Diff. = o".so5 J ^ery steaay. The small star decidedly pale blue, and bears but the most feeble illumination : the ob€ervations are so excessively difficult, that the results are somewhat ques- tionable. Mean Result. Position 86° 13' sp ; Distance 5".ii7 ; Epoch 1825.70. No. DCCCXXIX. R. A. 23^ 14"* ; Decl. 9° 27' S. Struve, 778 ; P. XXIII. 69. Double ; 7t and 8th magnitudes. Passy ; October 9, 1824 ; Seven-feet Equatorial. Position = 4*> 28' njp I 5 Obs. I Diff. Distance = 8". 144 j 5 Obs. | Diff. Position = 40 28' n;? I 5 Obs. I Diff. = i" i' | Passy ; November 3, 1824 ; Seven-feet Equatorial. 7i ^nd 8th magnitudes. Position =: 3° 40' np \ 5 Obs. I Diff.= 1° 9' ) Distance =7".8i 9 | 5 Obs. | Diff. = o".649 j • • • • Observed when 70 minutes west of the meridian. Mean Result. Position 4° 4 np ; Distance 7^.981 ; Epoch 1824.80. 508 Mr. South' s observations of the apparent distances No. DCCCXXX. R. A. 23^ 18™ ; Decl. 0° i6'N. X Piscium ; Struve, 782 ; VI. 62. Double ; 5th and 12th magnitudes. Passy ; October 9, 1824 ; Seven-feet Equatorial. Position = 74° 42' np I 5 Obs. DifF. = i° 3' \ p„ce«ivelv difficult Distance = 2' 29".548 ] 5 Obs. DifF. = 2". 1645 ^"""^"^^'^ ditticult. The small star under a very slight illumination, becomes invisible. Passy ; November 9, 1824 ; Seven-feet Equatorial. 5th and 12th, or 13th magnitudes. Position = 75° lo'np c Obs. I Diff. = \° xz' } -c • t j-a: i^ Distance = 2' 3o".632^ 5 Obs. | DifF. = 2".76s \ Excessively difficult. Night not very favourable. Mean Result. Position 74° 56' np; Distance 2'so".090 ; Epoch 1824.82. Sir W. Herschel gives no measures of this star. (H.) No. DCCCXXXI. R. A. 23^ 21" ; Decl. 4° 17' N. Struve, 783 ; Mayer. Double ; 8th and Si- magnitudes. Passy ; October 14, 1824 ; Seven-feet Equatorial. Position = 83° 58' sp 5 Obs. I DifF. = 1° 12' ) Distance = 1 1".654 5 Obs. | DifF. = 0^745 J • • • • Passy ; November 3, 1824 ; Seven-feet Equatorial. 8th and SJ magnitudes. Position = 84° 5' *j) ! 5 Obs. I DifF. = !<> 17' 1 Distance::: ii".709 j 5 Obs. j DifF. zz ^".2yJ^.) • • • • Stars 37 minutes west of the meridian, at the time of observation. Mean Result. Position 84° 1' sp; Distance ii".68i ; Epoch 1824.81. and positions of 45S double and triple stars, &c. 309 No. DCCCXXXII. R. A. ^s"" 23" ; Decl. 42° 50' N. II. 94 ? or Nova ? * Double ; 9th and 11th, or 12th magnitudes. Passy; September 24, 1825 ; Seven-feet Equatorial. Position 1=44° 14' n/) Distance zz 4". 374 Position = 39° 33' np DifF. = 1° 8' DifF. n o".553 ^South. DifF. = 5° 2' J 5 Obs. 5 Obs. 5 Obs. Position = 38° 55' « j) I 5 Obs. j Diff. = 5° 42'. Capt. Beaufort. The small star is so extremely faint, that Capt. B. cannot procure any observations of distance. Night tolerably favourable. Passy ; September 27, 1825 ; Seven-feet Equatorial. 9th and 12th magnitudes. Position r= 44° 45' np Distance = 4".405 5 Obs. 5 Obs. DifF. = 4° 1 5' ) c T^-ir « - /-South. Diff. =: o .577 ) Measures which merit but little confidence ; the small star so excessively indistinct, that Captain Beaufort cannot obtain any observations. Mean Result. Position 41° 52' np (20 Obs.); Distance 4".389 (10 Obs.); Epoch 1825.74. Sir W. Herschel's observations of this star (if II. 94) are as follows : 1783.66, Position S4° 24' np; 1802.5, 35° 6^ np. These compared with the present, present a great disagree- ment. If we take the mean of the two earlier observations we get S5° 10' np, and 1 793-1 for a mean epoch, which compared with the measures of 1825 give an arc of 6° 42', described in an interval of 33 years, or about + o°.203 per annum. The data, it is true, are precarious, but the conclu- sion is such as to render it worth while to watch this star in future. (H.) * This star was found by sweeping in the neighbourhood of the 784th star of Struve's Catalogue. The star however whose place is there given, was only seen as a single star : it is therefore very probable that the one here measured is Sir W. Herschel's star. 310 Mr. South's observations of the apparent distances No. DCCCXXXIII. R. A. 23^ 32™ ; Decl. 5° if N. Struve, 785; Hist. Casl. 128. Double ; 8th and 8j magnitudes. Passy ; October 9, 1824 ; Seven-feet Equatorial. Position =40° 59' raj? | 5 Obs, | Distance = 3° 58'. Passy ; November 3, 1824 ; Seven-feet Equatorial. 8th and 8f magnitudes. Position z= 41° o' rap I 5 Obs. I DifF. = 2° 5' ) Distance = 14", 63 3 | 5 Obs. J Diff. z= o^6o r j • • • • Passy; September 9, 1825 ; Seven-feet Equatorial. 8^ and 9tli magnitudes. Position = 42° 44' np I 5 Obs. I DifF. = i° 32' V r):/!:-^,. Distance = i^'.s 18 | 5 Obs. | DifF. = o".^Z6 ] ^^^uit. During the observations, the small star was frequently very indistinct. Night very hazy. Mean Result. Position 41° 34' np ; (15 Obs.); Epoch 1825.10 ; Distance 14".575 ; (10 Obs.) ; Epoch 1825.26. No. DCCCXXXIV. R. A. 23^ 38- ; Decl. 27° 28' N. Struve, 787 ; IV. 107. Double ; 6th and 10th magnitudes. Passy ; October 14, 1824 ; Seven-feet Equatorial. Position = 53°5o'ra/| 5 Obs. DifF. = 1° 15') t? ^ _ , -i-a: 1* Distance = 32".4Si | 5 Obs. DifF. = i'Jl \ ^""^'^"^^^y ^^^^"1^' Night is very fine, but the small star scarcely bears any illumination. Passy; November 3, 1824 ; Seven-feet Equatorial. 6th and 11th, or 12th magnitudes. Diff! = o".i92 } Excessively difficult. 5 Obs. 2 Obs, Position = 53° 13' w/ Distance zz 31 ".666 The small star will not bear the slightest illumination. Mean Result. Position 53° 31' w/(io Obs.); Distance 32''.248 (7 Obs); Epoch 1824.81. The present angle differs — 3° 10' from that of 1783. (H.) and positions q/'458 double and triple stars ^ &c, 311 No. DCCCXXXV. R. A. 23»» 39™ ; Decl. 3° 46' S. 20 Piscium ; Struve, 788. Double ; 6th and 12th magnitudes ; small, blue. Passy ; October 14, 1824 ; Seven-feet Equatorial. Position = 170 10' np I 5 Obs. | Diff. = o° 25' | Excessively difficult. Distance = 2' 5o".5oo \ 5 Obs. | Difr. = 2".5243 ' Night extremely fine, but the small star will scarcely bear any illumination. Passy ; November 25, 1824 ; Seven-feet Equatorial. I 7tli and 1 5th magnitudes. Position = i/** 17' njo 1 5 Obs. | Diff. = 0° 33'. Excessively difficult. Observations of distance cannot be procured, although the night is fine. Passy ; September 28, 1825 ; Seven-feet Equatorial. 6th and 12th, or 14th magnitudes. Distance = 2' 5i".349 | 5 Obs. | Diff. = o".9i3. Excessively difficult. The small star becomes invisible under the most feeble illumination. Mean Result. Position 17° 13' np ; Epoch 1824.83 ; Distance 9! 5o".924 ; Epoch 1825.26. No. DCCCXXXVI. R. A. 23^ 49" ; Decl. 23° 22' N. Nova; Double ; 8^ and 11th magnitudes. Passy ; September 10, 1825 ; Seven-feet Equatorial. Position = 43° 54.' «p I 5 Obs. Distance = 9".47 1 I S Obs. Diff. = G° 35' I „ Diff =o".48il«^^y- The small star is so extremely indistinct, and the measures so excessively difficult, that the results are perhaps a little inaccurate. Passy ; September 15, 1825 ; Seven-feet Equatorial. 8 J and 11 th magnitudes. Position = 45; 23' np I 5 Obs. Diff. = 4° V \ Excessively difficult. Distance = 9.252 | 5 Obs. Diff. = o .962 3 ' The small star is pale blue, and bears but the slightest illumination. Mean Result. Position 44° 38' np\ Distance 9^361 ; Epoch 1825.70. 312 Mr. South' s observations of the apparent distances No. D CCCXXXVII. R. A. sis'" 54" ; Decl. 65"" 6' N. Struve, 794- Double ; 8th and 9th magnitudes. ,(1 Passy ; October 21, 1824 ; Seven-feet Equatorial. DifF. - 3° 22' ) o DiiF.=o".8i7l South. Position == 20° 6' nf | 5 Obs. Distance r: i5"'.52o j 5 Obs. Position = 18° 15' w/ 1 2 Obs. I Diff. = 0° 30' 7 ,yr -r Distances 1 5".285 | 5 Obs. | DifF. = 2".oi9 j ^'' Troughton. Passy ; October 7, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. 5 Obs. 5 Obs. Position = 19° 48' nf Distance — I5''.6i8 DifF. =:o°45' ) <,« DifF. = o".8l7r°^^«' Position = 1 8° 44' nf Distances 15". 2 87 5 Obs. I DifF. = 1° 5' \ ^ ^ ^ 5 Obs. I DifF. = 2".332 J ^^P*' Be^^'ORT. During Capt. Beaufort's observations, the stars became very faint, in consequence of the deposition of dew on the exterior and interior surfaces of the object-glass. Mean Result, Position 19° 24' nf {in Obs.) ; Distance 15",427 (20 Obs.); Epoch 1825.28. No. DCCCXXXVIII. R. A. 23^ 65"^ ; Decl. 61° 17' N. 9 Cassiopeise ; Struve, 795 ; V. 79.* Double ; 6th and 10th magnitudes ; small, blue. Passy ; October 21, 1824 ; Seven-feet Equatorial. Position =: 74° 25' s p Distance =z 4' 5".682 5 Obs. 5 Obs. DifF. = 0° 29' ) T^.fl- . DifF.= i".298l^^^^"^^- Passy ; November 16, 1824 ; Seven-feet Equatorial. 6th and 10th magnitudes. "is'- Position = 74° 21' sp Distances: 4' 5".i65 S Obs. [DifF. = 0O32' \^.^ ,^ DifF. = i".i54]^^ifficult. 5 Obs. Mean Result. Position 74° ^s' sp\ Distance 4' 5"- 42 3 ; Epoch 1824.84. • The star here measured is called V. 79 in M. Struve's Catalogue, but is manifestly a different star. (H.) C 313 3 RE -EXAMINATION OF THIRTY-SIX DOUBLE AND TRIPLE STARS, THE DISTANCES AND POSITIONS OF WHICH, AS OBSERVED BY MR. HERSCHEL AND MR. SOUTH, WERE PUBLISHED IN THE PHILOSO- PHICAL TRANSACTIONS FOR 1824. No. L R. A. o^ 38" ; Decl. 56° 51' N. fi Cassiopeise ; IIL 3 ; H. and S. 8. Double ; 6th and 9th magnitudes. Position = 8° 2i'n/ Distance = 9".968 Position = 8° 1' ra/ Distance = g".7S6 Passy ; October 7, 1825 ; Seven-feet Equatorial. 7 Obs. I Diff. = 2° 3' ?g S Obs. I DiiF. = o".889 j^o^^H. 7 Obs. i DiiF. = 3° 45' ■) ^ ^ « 5 Obs. I DifF. = o".5S3 J<^^P<^' Beaufort. Night not at present favourable. Observed when 40 minutes west of meridian. Passy ; October 11, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position = 6° 42'»/| 7 Obs. | DifF. = i' 36' 7 j^-n-.. Distance= 9".959 | 5 Obs. | Diff. = o-.^S^^'^^""^'' Night foggy; the small star very indistinct: observed when 50' west of meridian. Passy ; October 12, 1825 ; Seven-feet EquatoriaL 6th and 10th magnitudes. Position = 6° 2' n/j 7 Obs. Distance = 9".736 | 5 Obs. DifF. = 1° 26' 7 -r.-a: ,^ Diff.=:o".745l^'^'"^'* Observed when one hour west of the meridian with 181. The stars, which have hitherto been remarkably steady and well defined, are now suddenly so excessively unsteady and ill defined, that to persevere in observing is altogether useless. ^ MDCCCXXVI. S S ^14 Mr. South' s re-examination of the apparent distances No. I. R. A. o^ 38" ; Decl. 56° 51' N. ri Cassiopeiae ; III. 3 ; H. and S. 8. continued. Passy ; October 13, 1825 ; Seven-feet Equatorial. 7th and 10th, or 1 1th magnitudes. Position =: 5° 59' nf Distance = 9".9ii ^8^::lES:lJ-i64}^''^'««-"- Observed when one hour west of the meridian. The fog is now become so dense, that the stars are scarcely perceptible. Passy; October 16, 1825; Seven-feet Equatorial. 6th and 1 0th magnitudes. Position = 6® 27' nf Distances io".o67 7 Obs. 5 Obs. DifF. = 2° 40' ) j^.a. ,^ Diff. = o".i84j^^^^"l*' Night very foggy ; stars ill defined and unsteady. A continuation of bad weather from this date till the 22nd instant, v^^hen the observatory at Passy was demolished, ren- dered further observations of this star impracticable. Mean Result, Position &* 55' nf{4>^ Obs.); Distance 9".904 (so Obs.); Epoch 1825.78. In 1821.9 the angle was measured at ?** 9' nf. The motion therefore in 3.9 years appears only to have been o'' 14', direct, whereas computing on the annual motion + o°.5i33 it should be 2° o'. The observation of 1821 is a mean of not more than 7 single measures. It is possible therefore that it may be somewhat erroneous, though proba- bly not to the whole extent ( 1° 46') which this discordance would require ; yet a trifling error in the present measure or in the angular velocity would reconcile all. Meanwhile the main point, the direction of the motion, agreeing, may be regarded as confirming the result already arrived at. (H.) and positions of 36 double and triple stars ^ &r 315 No. II. R. A. 5^ o'" ; Decl. 8" 53^' S. IV. 43 ; H. and S. 50. Double ; 8th and 10th magnitudes ; small, blue, and bears only a very feeble illumination. Passy ; January 17, 1825 ; Seven-feet Equatorial. Position = 8° 17' nf Distances 2o".755 5 Obs. 5 Obs. Diff = l^ifA ^^^^^^^^y difficult. Observed when 10 minutes west of the meridian; the dew on the object-glass is very troublesome. Passy ; January 19, 1825 ; Seven-feet Equatorial. ^th and 11th, or 12th magnitudes. Position = 9° 8' nf Distance = 22".349 c Obs. I DifF. = o° 45' ) ^j ^ , ,.3. . c Obs. Diff. = i".202 \ Extremely difficult. 5 Ubs. J Dltt. = I".202> Observations made on the meridian ; night very fine. Passy ; February 6, 1825 ; Seven-feet Equatorial. 8th and 11th magnitudes. Distance =: 22".643 | 5 Obs. | Diff. =r i"-77g» Extremely difficult. Should this set favour one series of the former observations more than the other, I feel so little confidence in them whilst obtaining them, that I would not reject either, but would prefer receiving the mean of all, as a final determination. Night tolerably clear, and the stars very steady. Mean Result. Position 8° 42' nf {10 Obs. ) ; Epoch 1825.05 ; Distance 2i".9i6(i5 Obs.); Epoch 1825.06. Until arranging the work for presentation to the Royal Society, I was not aware that the former memoir contained the following observations of this double star, made by Mr. Herschel and myself. Position io<* 6' nf; Distance 2i".763; Epoch 1821.97. 316 Mr. SouTH^s re-examination of the apparent distances No. III. R. A. 5^ 22" ; Decl. i6* 56' N. III. 9S ; H. and S. 58. Double ; 8th and 8-§- magnitudes. Passy ; December 23, 1824 ; Seven-feet Equatorial. Position = 51° 27' sf 5 Obs. I Diff. = 1° 12' ) j^. . ^^ Distance = i i".03i 5 Obs. | DiflF. = o'.sos ] ^^^^^ ^^^ ^^'^' Passy ; December 23, 1824 ; Portable Transit. Observed R. A. of the larger star = 5** 22' 8''.o6. Passy ; December 31, 1824 ; Seven-feet Equatorial. 7th and 71 magnitudes. Position =51° 9' sf 5 Obs. I DifF. = 2° 35' 1 y unsteady Distance = id'.e^z 5 Obs. | Diff. = o".36o5 ^^^ unsteaay. Night unfavourable ; stars not well defined. Mean Result. Position 51' 18' 5/; Distance io''.86i; Epoch 1824.99. This star was re-measured unintentionally ; I was not aware that observations of it were communicated in the former memoir, which give for the Position 52° 4' sf; and Distance 9".790 ; Epoch 1821.96. The positions agree very well, but the distances differ more than could be wished. No. IV. R. A. 6^ 20"° ; Decl. 6^ 55' S. 11 Monocerotis; H. andS. 71. Triple ; perhaps quadruple ; but the fourth star is very dis- tant. A 6^, B 7th, C 7t, and D of the 10th magnitudes. Measures of A B. Blackman-street ; February 15, 1824 ; Five-feet Equatorial. Position == 40° 38' sf Distance = 8". 280 c Obs. Diff. = 0° CO' ) o SObs. Diffrro^Lir^^"^"- Blackman-street ; March 2, 1824 ; Five-feet Equatorial. Position = 400 s' */ I 4 Obs. I Diff. = 0° 45' ) ^ Herschel Distance = 7".7oo | 5 Obs. | Diff. = o".727 5 ^^' "erschel. Night hazy. and positions of 36 double and triple stars , &c. Si 7 No. IV. R. A. 6^ 20'" ; Decl. 6° 55' S. 11 Monocerotis ; H. and S. 71. continued. Measures of B C. Blackman-street ; February 15, 1824 ; Five-feet Equatorial. 7th and 7h magnitudes. Position = 13° 53' sf I 5 Obs. DiiF. = 2° 26' 1 . Distance = 3",266 | 5 Obs. DifF. = ©".758 j ^o^^h. Blackman-street ; March 2, 1824 ; Five-feet Equatorial. Position = 13° 25' sf I 5 Obs. I DifF. = 1° 10' 7 ^ Herschel Distance = 3".309 | 2 Obs. 1 DifF. = ©".253 } ^"^^ ^^^schel. Night hazy. Observations of the distant star cannot be obtained. Measures of B D. Blackman-street; February 15, 1824 ; Five-feet Equatorial. 7th and 10th magnitudes. Position = 66" 33' wj? I 3 Obs. I DifF. = 0° 50' i <, Distance = 4' io".gs7 \ 3 Obs. | Diff. = o".88s 5 ^^uth. Mean Result. of A B. Position 40** 23' sf{9 Obs.) ; Distance 7'''.990 (10 Obs.) ; Epoch 1824.12. of BC. Position 13° 39' sf{io Obs.) ; Distance s".278 (7 Obs. ) ; Epoch 1824.12. of BD. Position 66° 3 3' wj> (3 Obs.); Distance4'io".957(30bs.); Epoch 1824.12. This star was measured under the idea that it was an unobserved star. Our measures in the former paper are for the position of AB. 39° 29' sf; of BC. 10° 41' sf ; of AD. 67° 20' np ; 1822.09 ; and for the distance, of A B. 6".862 ; of B C. 3".243. The distances ascribed to A B disagree, it is true, more than a second, a very considerable quantity on so small a distance, it must be confessed. It is probable that the real distance is a mean between them, or 7".42. 318 Mr, South's re-examination of the apparent distances No. V. R. A. &" so" ; Decl. 59° 37' N. 12 Lyncis ; I. 6 and III. 22 ; H. andS. 74. Triple ; A of the 7th, B of the 7f , and C of the 9th magnitudes. Measures of A B. Passy ; April 1, 1825 ; Seven-feet Equatorial. Position = 63° 32' sf\ 6 Obs. | Diff. = 4° 45'. Very unsteady. Observed when 1 J hour west of the meridian with 273. Passy; April 3, 1825 ; Seven-feet Equatorial. 7th and 7J magnitudes. Position ss 6&> 22' sf Distances 2".488 5^gS;:|Eil; = o°i6';lBXStrongt.mghe. 5 Observed when one hour west of the meridian, with a power of 413, which sepa- rates the discs of the stars completely : they are most beautifully defined. The measures of distance are a little difficult, because the instrument is thrown into tremours by the wind : the sun scarcely below the horizon when the observations were taken. No artificial illumination necessary. Passy ; April 4, 1825 ; Seven-feet Equatorial. 7J and 8th magnitudes. Position = 63° 15' «/! 7 Obs. Distance = ^".469 | 5 Obs. DifF. =:: 2« 30' I p,.«; ,^ One hour and a half west of the meridian when observed with 41 3 ; stars at times well defined, but are very unsteady. Passy ; April 5, 1825 ; Seven-feet Equatorial. 7th and 71 magnitudes. Position = 63° 59' sf I 7 Obs. DifF. = 3° 1 1' 7 Unsteadv Distance = 2''.63o | 5 Obs. DifF. = o".432 | ^"^^^^^y* Observed with 41 3. Measures of A C. Passy ; April 1, 1825 ; Seven -feet Equatorial. 7th and 9th magnitudes. Position =: 34° to' np \ 6 Obs. | DifF. = 2° o'. Very unsteady. Observed when i| hour west of the meridian with 273. and positions 0/36 double and triple stars y &c. 319 No. V. R. A. 6^ so" ; Decl. 59** si N. 12 Lyncis ; I. 6. and III. 22 ; H. and S. 74. continued. Passy ; April 3, 1825 ; Seven-feet Equatorial. 7th and 9^ magnitudes. Position = 36- 35' np ; Obs. I DifF. z= 2" n' 7 g yj . Distance zz 8".7S4 5 Obs. | Diff. = o".3 12 j ^^ twuignt. Angles obtained with the greatest facility ; distances rather difficult, the instrument being agitated by the wind ; magnifying power used 41 3. Passy; April 4, 1825 ; Seven-feet Equatorial. 7J and 91 magnitudes. Position = 35° 13' np I 7 Obs. I Diff. = !<> 20' ) Unsteady Distance = 9".379 | 5 Obs. | Diff. = o".36o5 '^"s^^^^/- Observed with 413, when i^ hour west of the meridian. * Passy; April 5, 1825 ; Seven-feet Equatorial. 7k and 9th magnitudes. Position = 35° 1/ np 7 Obs. | Diff. = 1° 58' ) Unsteady Distance = 9 '.420 5 Obs. | Diff. = 0^577 5 '-'"^teaay. Obserred with 413. Mean Result. of A B. Position 64° 21' sj(27 Obs.); Distance 2^.529(15 Obs.) ; of AC. Position 35° si'w^ (27 0bs); Distance 9"- 184(1 5 Obs.); Epoch 1825.25. There is a considerable change in the position of the close star since the year 1823. At that time ( 1823.28) the angle was 68"* 39' 5/ (See Phil. Trans. 1824. Part III.) Hence it appears that the small star has continued its motion in the direction there assigned to it ; and, if we may confide suffi- ciently in both data, with an accelerated velocity, for the computed motion corresponding to an interval of 2.0 years would be — 1°. 148, whereas the observations make it —4° 18' or — 4°. 3. Meanwhile the direction of the motion is as pre- dicted, and we may therefore regard the reality of this star's rotation as fully confirmed. ( H.) 320 Mr. South' s re-examination of the apparent distances No. VI. R. A. 7*^ 23™ ; Decl. 32° ifN. Castor ; II. 1 ; H. and S. 81. Double ; 3rd and 4th magnitudes. Passy ; February 18, 1825 ; Seven-feet Equatorial. Position = 7° 8' *p I lo Obs. | Diff. z= i° 54'. Tolerably steady. Observed within half an hour of either side of the meridian ; no other double star visible. During the measures, the larger star passed through all gradations of magnitude, between the third and ninth ; a circumstance which it is necessary to mention, as in taking the mean they ought not to be allowed a value, proportional to their number. Passy; March 31, 1825; Seven-feet Equatorial. 3rd and 4th magnitudes. Position = 6° 51' «/) I 7 Obs. | DifF. =: 0° 59'. Tolerably steady. Observed when 12 minutes west of the meridian. Passy; April 3, 1825 ; Seven-feet Equatorial. Srd and 4th magnitudes. Position = 5° 59' sp 7 Obs. | Diff. = 1° 3-6' Distances ^'.^^g SObs.|Diff.=o".529}^y^^y^'S^*- Stars beautifully defined, and as steady as possible j the sun shining ; not a cloud visible : observations made with 787. Passy ; April 4, 1825 ; Seven-feet Equatorial. 3rd and 4th magnitudes. Position =fz'sp 7 Obs. I Diff. = 1° 1 1' ) Unsteady Distance = 4".796 5 Obs. | Diff. = o".288i ^"steady. Observed with 181, when 20 minutes west of the meridian. Passy ; April 5, 1825 ; Seven-feet Equatorial. 3rd and 4th magnitudes. Diff. r= Diff. :=i".48i}2y^i"s^*- Position = 6° 48' «;? I 7 Obs. Distance = 4". 958 | 5 Obs. Observed on the meridian with 787 j stars exquisitely defined, and as steady as possible. Passy; April 6, 1825 ; Seven-feet Equatorial. 3rd and 4th magnitudes. Position = 6° 22' sp I 7 Obs. I Diff. = 1° 18' ) g daylieht. Distance = 4".826 | 5 Obs. | Diff. = o".48 1 ] ^^ ^^X^S'^^- The sun shining ; stars very steady, and extremely well defined. Observations made with 513, when 10 minutes east of the meridian. and positions of sQ double and triple stars , &c. 321 No. VI. R. A. 7^ 23" ; Decl. 32° 17'N. Castor ; II. 1 ; H. and S. 81. continued. Mean Result. Position 6'' 42' sp (42 Obs.) ; Epoch 1825.23 ; Distance 4".767 (20 Obs.) ; Epoch 1825.26. Note J In taking the mean, the ten observations of February 1 8 are considered equivalent to the seven of which the other sets are composed. These measures, compared with those recorded in the Phi- losophical Transactions for 1824, afford, in the short interval of 2^.12, a very satisfactory verification of the quantity as v^ell as of the direction of the motion there assigned. The angle at that epoch (1823.1 1) was 5° 1' sp. It is now 6° 42' sp. The motion then is — 1° 41' or retrograde, as it ought to be. Now, if we compute the motion on the supposition of the actual angular velocity being (as there assigned) -*-o°.777, we shall find — 1° 38', differing insensibly from the observed quantity. That this degree of exactness is not quite acci- dental, other similar instances to be adduced will convince MS. (H.) No. VII. R. A. 7^ 58" ; Decl. 28° o' N. 11 Cancri ; I. 11 ; H. and S. 88. Double ; 8th and 9^ magnitudes. Blackman-street ; March 12, 1824; Five-feet Equatorial. Position == 83° 24' np Distance = 4".694 5 Obs. J DifF. = 3° o' 5 Obs. I Diff.= o".8s3 5 • • • • Blackman-street ; March 31, 1824 ; Five-feet Equatorial. 8th and 9 J magnitudes. Position =: 83* 7' w j9 Distance = 4"'659 MDCCCXXVI. 1 1 5 Obs. DifF. = 2° 46' 7 5 Obs. Diff. = o".22iJ • • • ^ 322 Mr. South's re-examination of the apparent distances No. VII. R. A. 7^ 58™ ; Decl. 28° o' N. 11 Cancri ; I. 11 ; H. and S. 88. continued. Mean Result. Position 83° 15' np; Distance ^".G'je ; Epoch 1824.21. When this star was measured, I supposed it to be the star whose R. A. in Struve's Catalogue is given 7^ 54'.5 ; Decl. 28* o' N. ; whether it is, or is not 11 Cancri, I cannot say; but it is unquestionably synonymous with the double star No. 88 of the collection observed by H. and S. and is the star observed by Sir W. Herschel. Our former measures were. Position 84° 30' np; Distance 4".498 ; Epoch 1822.21. No. VIII. R. A. 8^^ 2" ; Decl. 18° 1 1' N. f Cancri ; I. 24 and III. 19 ; H. and S. 90. A very pretty double star ; 6^ and 7th magnitudes. Blackman-street ; March 13, 1824 ; Five-feet Equatorial. Position = 6f ci' «/ 5 Obs. DifF. = 1° 51' i p^„„ , ,, , , ,. . Distance = 6".ao9 '' 5 Obs. Diff. = o".8s3 } ^'™*'^^^^y '^^^^y* Observations extremely satisfactory. Blackman-street ; March 31, 1824 ; Five-feet Equatorial. 7th and 71 magnitudes. Position = If 9'sf I 5 Obs. I DifF. = 0° 55' \ Tolerably steadv Distance = 6". 181 J 5 Obs. | DifF. = o".69S ] ^ ^^^raoiy steady. Observed when two hours west of the meridian ; but the stars are well defined. Passy ; January 17, 1825 ; Seven-feet Equatorial. 7 J and 8th magnitudes. Position = 7o«> 15' «/ 1 S Obs. j DifF, ;= i° 49' The position observed on March 13th, 1824, differs more than might be wished with that obtained subsequently ; still the favourable circumstances under which the discordant set was procured, would not justify their rejection ; allowing all equal weight, we have for the and positions of 36 double and triple stars y (^c. 323 No. VIII. R. A. 8^ q' ; Decl. 18M1' N. 5" Cancri ; I. 24 and III. 19 ; H. and S. 90. continued. Mean Result. Position 69'' 45' ^/ ( 15 Obs.) ; Epoch 1824.49 ; Distance 6^195 (10 Obs.); Epoch 1824.22. When this star was observed in Blackman-street, in 1824, and again at this place in January of the present year, I re- garded it as a new double star, and registered the observa- tions of it as such ; a comparison however of the results with the measures of f Cancri, leaves no room to doubt that the two stars are identical. Our former measures were Position 68** 17' sf; Distance 6".24i ; Epoch 1822.14. Observations however which immediately follow, show that the larger star is itself double ; hence some suspicion as to the accuracy of these and of former measures will naturally arise. Passy ; April 3, 1825 ; Seven-feet Equatorial. Triple ; A of the 7th, B of the 8th, and C of the 8th magnitudes. Measures of A B. The eye-pieces adapted to the micrometer hitherto used with this instrument being inadequate to communicate to the telescope sufficient magnifying power to enable me to pro- cure measures of thivS interesting close double star, I applied the micrometer of the Five-feet Equatorial,* which I had for- tunately brought with me from England : the powers thus obtained are 92, 157, 181, 327, 413, 5i3 and 787. As to the • To effect this change of micrometers, an alteration of the eye-tubes became necessary; on this, as on evefj/ other occasion, Mons*". Gambey supplied my wants so expeditiously yZwA. at the same time so' cotnpletely , that during my abode here, I scarcely felt the loss of Mr. Troughton. The advantage of having a.Jirst-rate Artist, resident within striking distance of our observatory, is almost incalculable. Passy, Oct. 22, 1825. 324 Mr. South's re-examination of the apparent distances No. VIII. R. A. 8^ 2'" ; Decl. i8° ii' N. f Cancrj ; I. 24 and III. 19 ; H. and S. 90. continued. value of the micrometer in seconds, rigorous examination has satisfied me that it is precisely the same with that of the micrometer formerly employed. The observations of this date, and of all subsequent to it, will be made by means of this micrometer. Position = 3i°2i' nf\ 7 Obs. | Diff. = 400' ^ difficult Distance =s o'Mj \ 5 Obs. | Diff. = d'.igz ] ^^™<^"^'^- Observed with 413, when a few minutes west of the meridian; the angles I con- sider very good j but the distances are perhaps a little inaccurate : the stars are well defined, but are very unsteady. Passy ; April 4, 1825 ; Seven-feet Equatorial. 7th and 8th magnitudes. Position = 32° 18' n/ 1 7 Obs. | Diff. = 6° 2'. Difficult. I cannot procure any measures of distance, the extreme unsteadiness of the stars rendering it impossible. Observed with 413. Stars tolerably well defined, and on the meridian at the time of observation. Passy ; April 5, 1825 ; Seven-feet Equatorial. 7tli and 8th magnitudes. Position s= 32® ^i'nf\ 7 Obs. Distance = i".o44 | 5 Obs. Diff. = 9° 12' ) j^.g. ,^ Diff. Observed with 413, a few minutes east of the meridian; stars unsteady, but at times well defined. Passy ; April 8, 1825 ; Seven-feet Equatorial. 7th and 8th magnitudes. Position = 32° 4' w/ 1 7 Obs. | Diff. = 7° 28'. Difiicult. Observed on the meridian with 413, but the stars are so unsteady, that measures of distance are impracticable. Passy ; April 14, 1825 ; Seven-feet Equatorial. 7th and 8th magnitudes. Position = 32° o' nf\ 7 Obs. | Diff. = 4° 7'. Very difficult. Observed with 41 3, with which power no measures of distance can be procured, owing to the extreme unsteadiness of the stars. I therefore applied 327, and obtained as results. ; Decl. 18° 11' N. f Cancri ; I. 24. and III. 19 ; H. and S. 90 ; continued. Sir W. Herschel, no measures could be procured, which is much to be regretted. The evidence for the motion of the more distant star C will be found in the Philosophical Transactions, 1824, Part III. p. 115. The change of quadrant— the great amount of the motion (23° 42' in 40^ years) and the circumstance of an error to that amount, or anything like it, being perfectly impossible from the considerable distance of the stars ; add, too, the regular gradations by which the change appears, from several inter- vening observations, to have taken place ; all these consi- derations place the motion of the distant star beyond dispute, and the present measures confirm it, the angle 67° 55' sf compared with that of 1822 (68° 17' sf) indicating a motion still in the same direction. Its amount, it is true, is only — 22' instead of — 1° 44' which the assigned velocity would give, but this is as near a coincidence as we have a right to expect in such small quantities. •If this be really a Ternary system connected by the mutual attraction of its parts, its perturbations will present one of the most intricate problems in physical astronomy. The difficulty will not be diminished by the circumstance of the rotations of the two small stars about the large one being (apparently at least) performed in opposite directions, being the reverse of what obtains in our planetary system, or by that of the deviations of the relative angular velocities from Kepler's law, being such as to indicate either great masses in all the three bodies, great excentricities in their orbits, or a different law of gravity from what obtains in our system. (H.) 328 Mr, South' s re-examination of the apparent distances No. IX. R. A. 8^ 16' ; Decl. 25° 7' N. v' Cancri ; II. 41 ; H. and S. 92. Double ; 8th and 9th magnitudes ; small, blue. Passy ; April 1, 1825 ; Seven-feet Equatorial. \ Position =z 520 13'n/ I 6 Obs. Diff. = i° 28' 7 ^ , , , Distance = 6". gig | 6 Obs. DifF. = o''.62s | tolerably steady. Observed with 179, when i| hour west of the meridian; the small star bears a very good illumination. Passy ; April 3, 1825 ; Seven-feet Equatorial. Sth and Qth magnitudes. Position = 52" 4/ nf I 7 Obs. I DifF. = 1° 16' ) ^^ , , , ^ . Distance = 6".SS2 | 5 Obs. | DifF. = o".2i6 J tolerably steady. Observed when 40 minutes west of the meridian with 181 j but examined with 41 3, with which power both stars are beautifully defined, and are as round as possible. Passy ; April 4, 1825 ; Seven-feet Equatorial. Sth and 9th magnitudes. Position = 52« 57' nfl 7 Obs. I Diff. = i® 48' \ r^ r , , ^ . Distance = 6''.773 | 5 Obs. | Diff. = o".s53 J Tolerably steady. Observed with 181, when 25 minutes west of the meridian. Passy ; April 5, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position =51° 56' nf 7 Obs. I Diff. = 2® 10' Kt . j Distance = 6".7i3 . 5 Obs. | Diff. = o".240 j Unsteady. Passy ; April 8, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 52° 35' nf\ 7 Obs. I Diff. = 1° 5' ) „ 1 ui . j Distance = 6".7i8 | 5 Obs. | Diff. = o".2i6l Tolerably steady. Mean Result. Position 52« 30 nf (34 Obs.) ; Distance 6". 742 (26 Obs.); Epoch 1825.26. and positions of 36 double and triple stars, &c. 329 No. IX. R. A. 8^ i6°» ; Decl. 25° 7' N. 0' Cancri ; II. 41 ; H. and S. 92. continued. The position here given compared with that of 1822.16 (Philosophical Transactions 1824, III.) indicates a change of only — 0° 17', being smaller, it is true, in quantity than the change ( — i<* 35') which ought to have taken place on the supposition of the angular velocity of — o°-5 14 there assigned, but in the right direction. If we recollect that the angle of 1822 is deduced from a mean of only 8 individual measures, it will not appear surprising that an error of a degree or somewhat more should have been committed in it. In such a case the coincidence of directions is in itself a confirmation as good as we have a right to look for. (H.) ^ No. X. R. A. 10^ lo'"; Decl. 20°45'N. y Leonis ; I. 28 ; H. and S. 113 ; Double ; 4th and 5th magnitudes. Passy; April 1, 1825 ; Seven-feet Equatorial. Diff! = f'Jos } ^^^^^' difficult. Position = 1 1° 43' sf I 7 Obs. Distance = z".^y6 | 6 Obs. Observed on the meridian with 273 ; the stars well defined, but not steady. Passy ; April 3, 1825 ; Seven-feet Equatorial. 4th and 5th magnitudes. Position = 1 i° I' */ 7 Obs. I Diff. = 1° 32' \ ^ ^, ... Distance = 3".oi7 "^ 5 Obs. | DifF. = o".384 J ^" *^' meridian. Observed with 413 ; stars very well defined but extremely unsteady, rendering the observations, particularly those of distance, difficult. Passy ; April 4, 1825 ; Seven -feet Equatorial. 4th and 5 th magnitudes. Position = 1 1O48' sf | 7 Obs. | DifF. = 2° 28'. On the meridian. Observed with 181 ; the extreme unsteadiness of the stars prevents me using a higher power. No observations of distance can be procured. MDCCCXXVI. U U 330 Mr, SouTH*s re-examination of the apparent distances No. X. R. A. loi* lo"* ; Decl. 20** 45' N. y Leonis ; I. s8 ; H. and S. 1 13 ; continued. Passy ; April 12, 1825 ; Seven-feet Equatorial, 4th and 5th magnitudes. Position = io° 27' sf Distances ^".^6l DifF. = 2° 22' ' = 2° 22' ) T\;a ^'1 .^^i Oti the meridian. Uiir. = o .432 3 7 Obs. 5 Obs. Observed with 327, the deepest power which the unsteadiness of the stars allows me to use advantageously. Passy ; May 4, 1825 ; Seven-feet Equatorial. 4th and 5th maa;nitudes. Position = 10° / «/ I 7 Obs. | DifF. = 4° 10'. Unsteady. Observed by twilight without artificial illumination, when 15 minutes west of the meridian. Passy; June 1, 1825 ; Seven-feet Equatorial. 4th and 5th magnitudes. Position = If 36'*/ 1 7 Obs. I DifF. = 1° 58' ) Unsteadv Distance = 2".652 | 5 Obs. [ DiiF. = o".264 5 '^^steaay. Observed by daylight with 41 3, when 40 minutes west of the meridian ; sun shining; not a cloud visible j stars at times well defined. Mean Result. Position 11° 17' sf (42 Obs.); Distance 2". 716 (21 Obs.) ; Epoch 1825.30. This position, compared with that of 1822.44, gives a motion of + 2** 53'. The supposition of an annual motion of + o°.30, assigned in the former Paper, would give + o°.54'. The present observations therefore confirm this motion fully in point of reality, and direction, but indicate an acceleration which (considering the number of observations) may have some claims to probability. The distances disagree more than might have been expected. (H.) and positions 0/36 double and triple stars, &c. 331 No. XL R. A. ii'^ 9" ; Decl. 32° 33' N. J Ursse majoris ; I. 2 ; H. and S. 122 ; Double ; 6th and 6^ magnitudes. Passy ; February 28, 1825 ; Seven-feet Equatorial. Position = 24° 53' *p 1 5 Obs. | Diff. = i* 42'. Difficult. Stars ill defined and unsteady ; observed with 273. Passy ; March 7, 1825 ; Seven-feet Equatorial. 6J and 7th magnitudes. Position = 24® 57' sp ] 12 Obs. | DifF. = 2° 30'. Tolerably steady. Observed when 15 minutes west of the meridian with 273 ; stars well defined. Passy ; March 20, 1825 ; Seven-feet Equatorial. 6th and 6| magnitudes. Position = 2C° iS' sp \ 4. Obs. I Diff. = 1° 35' ) ,,, j, Distance = 2'.o29 "^ | J Obs. | Diff. r= o".48i J ^ons. Bouvard. Position = 25° 11' sp 16 Obs. Distance ^ 2".oo9 | 5 Obs. Diff. = 2^ 35 ) c Diff =o".254 I South. Observed when a few minutes east and west of the meridian with 273, but during the measures of distance extremely unsteady. Passy; March 21, 1825 ; Seven-feet Equatorial. 6| and 7 th magnitudes. Position = 25° i' sp \ 7 Obs. I Diff. = 2° o' ) ^ ,, ... Distance = 2''.S72 j 5 Obs. | Diff. = o".673 J ^" *^^ meridian. Night hazy, stars tolerably steady, and are separated with a power of 179, with which the observations were procured. Passy ; April 3, 1825 ; Seven-feet Equatorial. 6th and 6| magnitudes. Position = 25°22 sp I 7 Obs. I Diff. = 1° 58' | Well defined. Distance = 2".368, j 5 Obs. | Diff. = o".2i63 but unsteady. Observed with 413, when 45 minutes west of the meridian. Passy; April 11, 1825 ; Seven-feet Equatorial. 6^ and 7th magnitudes. Diff. = 20 45' Observed with 181. Position =: 26° 12' sp .7 Obs Position = 26° 51' sp 7 Obs. Distance z= 2".387 The position obtained with 181 was taken when the stars were 10 minutes east of the meridian, and the observations with 413 when they were 10 minutes west of it. Obs. Diff. = o".44 7 5 Obs. j Diff = o".6oi I ""'^ 413. 33^ Mr. South's re-examination of the apparent distances No. XI. R. A. ii*' 9" ; Decl. 32° 33' N. f Ursae majoris ; I. 2 ; H. andS. 122. continued. Mean Result. Position 25* 28' sp (^5 Obs.) ; Epoch 1825.22 ; Distance 2".442 (15 Obs) ; Epoch 1825.25. In taking the mean the distances of March 20 are rejected ; if not rejected, the mean of the 25 observations will give distance 2". 2 73, Nothing can be more satisfactory than the confirmation these observations afford of the rapid motion ascribed to this remarkable star. In the interval of 1.97 year since the Epoch 1823.29 the jnotion has amounted to no less than 13° 55' y in the direction npsf, or — 7°.o25 per annum. The sudden diminution of velocity is however not confirmed. Indeed it rested on too short an interval, and on too few ob- servations (for such very close stars) to deserve great confi- dence. We cannot do better than recommend this star for the next 10 or 20 years to the constant and careful measure- ment of astronomers ; nor can we too strongly inculcate here the indispensable necessity of multiplying extremely their measures of position, to eliminate those errors of judgment to which the most experienced observers are liable in mea- sures of this sort. This done, there is no doubt of our arriv- ing at a precise knowledge of the elements and position of the orbit described by each about their common centre of gravity ; and the question of the extension or non-extension of the Newtonian law of gravity to the sidereal heavens — the next great step which physical astronomy has yet to make — will be effectually decided. (H.) and positions 0/36 double and triple stars ^ &c. SSS No. XII. R. A. iQ^ 13" ; Decl. 6° 19' N. 17 Virginis ; IV. 50; H. and S. 142. Double; 7th and 11th magnitudes. Passy ; April 3, 1825 ; Seven-feet Equatorial. Position = 66° 46' np Distance = 19". 795 7 Obs. 5 Obs. Diff. = 2° 35' > Unsteady. DifF. = o".625 ) Very unsteady. Measures extremely difficult, on account of light clouds : the angles were gotten when the stars were on the meridian ; but no observations of distance could be pro- cured till they were 40 minutes west of it. Passy ; April 4, 1825 ; Seven-feet Equatorial. 8th and 12th magnitudes. Position r; 65° 43' np Distance = i9".974 7 Obs. 5 Obs. DifF. = 1° 15' ) Very difficult. DifF. zz i".0345 Extremely difficult. Passy ; April 29, 1825 ; Seven-feet Equatorial. 8th and 1 1th magnitudes. Position = 66° f npXy Obs. I DifF. = i° 42' 7 Measures of consi- Distance = 19 ".5 96 | 5 Obs. | DifF. = o".4o8 3 derable difficulty. Passy ; May 10, 1825 ; Seven-feet Equatorial. Position = 66° 25' np Distance = 20". 274 7 Obs. I DifF. = 1° 47' ) Very difficult. 5 Obs. I DifF. = I ''.49 1 S Extremely difficult. Mean Result. Position 66° i^'np (28 Obs.); Distance i9".9io (20 Obs.); Epoch 1825.30. The difficulty of the measures of this star is no doubt the reason of the disagreement betv^een the result {69° 36'np) of the observations of 1823, and the present. The discordance however is unfortunately such as to prevent any certain conclusion as to the motion or rest of the stars from being dravv^n. (H.) 334 Mr. South' s re-examination of the apparent distances No. XIII. R. A. 12^ 32- ; Decl. o° 27' S. y Virginis ; III. 18 ; H. and S. 150. Double ; 8th and 8 i magnitudes. Passy ; April 3, 1825 ; Seven-feet Equatorial. Position = 7° 22' sf Distance = 3".2Sy 7 Obs. I DifF. = 3° 12' ) TT .. J SObs. I Diff.=o".3 12 1 Unsteady. The angles were observed with 413 j but the distances with 181 only, in conse- quence of the unsteadiness of the stars, which were at the time of observation a few minutes west of the meridian, Passy ; April 4, 1825 ; Seven-feet Equatorial. S Obs. I DifF. = 2° 20' ) ,, , , 5 Obs. I DifF. = o".6oi I ^^'y unsteady. Position = 6° 42' np Distance s= 3".! 52 The stars are of the 8th and Sf magnitudes. I tried to use a higher power than 181, but could not do it advantageously. Passy ; May 14, 1825 ; Seven-feet Equatorial. 8th and 8^ magnitudes. ' Positioil == 6? 5 5' rep Vf Obs. | DifF. = i" 9' 1 Distance= 3".325 j 5 Obs. | DifF. = ©".456 > * * ' * Observed when on the meridian ; stars tolerably well defined, but unsteady. Passy; May 31, 1825 ; Seven-feet Equatorial. 8^ and 9th magnitudes. Position = 6° 34' »p I 7 Obs. Diff. = 0° 51' ) ,;. ^ . Distance = 3".289 ^ | 5 Obs. DifF. = o".i8i j ^ery unsteady. Stars one hour west of the meridian ; at times tolerably well defined. Mean Result. Position 6° 53' np (28 Obs.) ; Distance 3".263 (20 Obs.); Epoch 1825.32. These observations confirm the motion attributed to the stars of y Virginis, and point out an acceleration in it, even more strongly than has been insisted upon in a former paper. This will appear by assembling all the observations with their epochs, as follows : and positions of 36 double and triple stars, &c. 335 No. XIII. R. A. ifiJ^ 32°' ; Decl. 0° 27' S. y Virginis; III. 18; H. andS. 150. continued. Epoch. Position. Interval. Angle described. Angular velo- city deduced. 1756.0 1781.9 1803.2 1820.2 1822.3 1825.3 54.4 np 40.7 30.3 15.3 13.4 6.9 25.9 21.3 17.0 2.1 3.0 13.7 10.4 15-0 1.9 6.5 0.528 0.490 0.882 0.905 — 2.167 This star therefore ought to be narrowly watched, as it should seem that the two component staVs are mutually approaching to their perihelion, or at least to their situation of maximum angular velocity. (H.) No. XIV. R. A. 12*' 32"^ ; Decl. 12^ 1' S. 58 (Bode) Corvi ; 145. 38 ; H. and S. 149. Double ; equal ; each of the 8th magnitude. Passy ; April 11, 1825 ; Seven-feet Equatorial. Position = 3 10 23' np or sf\s Obs. I Diff. = 2° 3' 7 Tjn.teadv Distance = 6". 2^ \ 5 Obs. | DifF. = o".264 ; Unsteady. Passy; April 12, 1825 ; Seven -feet Equatorial. 8th and 8| magnitudes. Position = 31° 32' np I 5 Obs. I DifF. = 0° 47' 7 Unsteadv Distance = s .910 | 5 Obs. | DiflF. = o".288 } '^"steady. Mean Result. Position 31° 27' np or sf{io Obs.) ; Distance 6".077 (lo Obs.) ; Epoch 1825.28. When this star was measured, I was not aware that olBser- vations of it by Mr. Herschel and myself had been commu- nicated to the Royal Society. Our joint result was. Position 29« 26' 5/; Distance 6''.88i; Epoch 1823. Si. 336 Mr. South's re-examination of the apparent distances No. XV. R. A. 14^ 37" ; Decl. 27° 51' N. £ Bootis ; I. 1 ; H. andS. 185. Double ; 2nd and 9th magnitudes. Blackman-street ; June 18, 1824 ; Five-feet Equatorial. Position = 55** 25' np \ 5 Obs. | DifF. = 2** 45'. Very satisfactory. Observations made by strong twilight, without artificial illumination of the wires. The evening remarkably favourable j stars extremely steady, and distant from ths meridian 20 minutes. Passy ; May 27, 1825 ; Seven-feet Equatorial. 2nd and 9th magnitudes. Position = 55° 58' np [ 7 Obs. DifF. = 3° 19' ) Distance = 3".7 1 3 | 5 Obs. DifF. = o".so5 ) • • • • Passy ; May 31, 1825 ; Seven-feet Equatorial. Position = 55° 30' «j9 I 7 Obs. | DifF. = 3° 4. Rather difficult. Observations of distance impracticable, on account of the unsteadiness of the stars. Passy; June 1,1825 ; Seven-feet Equatorial. 2nd and 9th magnitudes. Position := 53° 40' nj9 I 7 Obs. Distance = S"'S^S I 5 O^s. DifF. = i°42' ) ^-a: ,, Stars tolerably well defined, and on the meridian, but are very unsteady. Passy ; June 9, 1825 ; Seven-feet Equatorial. 2nd and 9th magnitudes. Position = 54° 58' wp I 7 Obs. I Difi^. = 2° 26' ^ <,. . Distance = 3".368 | 5 Obs. | DifF. = o".505 S ^^^^^y* Passy ; June 13, 1825 ; Seven-feet Equatorial. 2nd and 9th magnitudes. Position =53° 28' np Position 1= 53** 17' np Distance rz 3".oo7 7 Obs. I DifF. z= 2° 52' 1 Observed with 181. 7 Obs. DifF. = 2° 23' > 327. 5 Obs. I DifF. = o".336 3 181. Stars admirably defined. I never observed this difficult double star under more favourable circumstances : the results are entitled to very considerable confidence : the observations were procured when the star was a few minutes on either side of the meridian. and positions of 36 double and triple stars y &c. 337 No. XV. R. A. 14^ 37°^ ; Decl. 27° 51' N. g Bootis ; I. 1 ; H. and S. 185. continued. Passy ; June 14, 1825 ; Seven-feet Equatorial. 2nd and 9th magnitudes. Position — 53° 3S' np Distance = 3". 126 7 Obs. 5 Obs. DifF. = 2° 36' \ Rather difficult. Diff. = o".;2g( Difficult. = 2° 36'^ Observed with 181 ; stars on the meridian and well defined, but are not steady. Mean Result. Position 55** ^5'np (5 Obs.); Epoch 1824.47 ; Position 54° 21' np (49 Obs.) ; Epoch 1825,43 ; Distance 3".356 (25 Obs.) ; Epoch 1825.44. Taking the means of the above angles and epochs, allow- ing each a weight proportional to the number of measures on which it rests, we get for the mean Epoch 1825.34 the angle of position 54° 26' np. This, compared with the measures of 1822, gives +1° 27' for the observed motion in the interval of 2.79 years. The motion computed on a supposition of -f- o°.4378 per annum assigned in a former paper, should be + 1° 14', differing insensibly from that actually found by observation. The motion of this star is therefore very satisfactorily confirmed both in direction and quantity ; and when we reflect on the extreme difficulty of it (in respect of position), this will serve to give great confi-* dence in results which depend on a great number of mea- sures, however wide of the mark individual measures may be. (H.) MPCCCXXVI. XX 338 Mr. South's re-examination of the apparent distances No. XVI. R. A. 14^ 43™ ; Decl. 19° 51' N. I Bootis ; II. 18 ; H. and S. 187. Double ; 6th and 8th magnitudes. Passy ; April 3, 1825 ; Seven-feet Equatorial. Position = 66° 22' np Distance = 7".668 7 Obs. 6 0bs. '. — d'.jzi ] ^^^ unsteady. DifF. = I DifF. Observed when 40 minutes east of the meridian. Passy ; May 27, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. Position =: 68° i6' n/) I 7 Obs. Distances 7*.8 1 4 | 5 Obs. Observed on the meridian ; but the night is unfavourable. DifF.= i°54' Kt ^ J DifF. = o".673|U"^teady. Passy ; May 31, 1825 ; Seven-feet Equatorial. 6th and 8th magnitudes. 5 Obs! I Diff:= o''.48i } Very unsteady. Position = 67° z' np Distance = 7"-949 Observed on the meridian. Passy ; June 1, 1825 ; Seven-feet Equatorial. 6\ and 9th magnitudes. Position = 66° ib' np\j Obs. I Diff. = 2° 3' ) ^t <■ a Distance = 7".672 | 5 Obs. | DifF. = o".889 ] "^nsteaay. Observed with 181 ; stars on the meridian, and at times well defined ; a power of 413 showed the larger of the two stars as round as possible. Mean Result. Position 67° o' np\ Distance 7^.776; Epoch 1825.37. In the former communication (Phil. Tran. 1824. III.) it is remarked that the continuance or decrease of the then angular velocity of about 1° per annum for a few years, would decide the question of rectilinear or orbitual motion. The present observations, then, go a great way towards de- ciding this interesting question, as, so far from indicating any retardation, their tendency hes the other way. In fact, (supposing them free from error), no less than — 3° 54' have been described in 2.74 years, being at the rate of — i".42o per annum. This star therefore merits peculiar attention, as the great variation of its distance gives reason to suppose a great eUipticity, or considerable inclination of its orbit. (H.) . and positions of 36 double and triple stars ^ ^c. 339 No. XVII. R. A. 15^ IS'" ; Decl. 38^ 1' N. sf fi Bootis ; I. 17 ; H. and S. 203. Double ; 8th and 10th magnitudes. Passy ; June 12, 1825 ; Seven-feet Equatorial. Position = 64° 14' np \ 7 Obs. | DifF. = 1° 29' [ Difficult. Observed when on the meridian with 327 : I could not obtain any measures of distance, on account of the extreme unsteadiness of the stars. Passy ; June 13, 1825 ; Seven-feet Equatorial. 9th and 10th magnitudes. Position = 63° 32' «P I 7 Obs. DiiF. = 3° 9' \ niffi-nlt Distance = i".396 I 5 Obs. | Diff. = o".43z J-^^^cuit. Observed with 327, when on the meridian. Measures satisfactory. Passy ; June 17, 1825 ; Seven-feet Equatorial. 8| and 10th magnitudes. DifF. =3° 39' DifF. = o''.4o8 I Easy. Position r= 63° z^'np I 7 Obs. Distance r= i"-377 | 5 Obs. Observed with 327 : stars well defined, and 35 minutes east of the meridian. Passy ; June 19, 1825 ; Seven-feet Equatorial. 9th and 9^ magnitudes. Position = 63° 25' np I 7 Obs. I Diff. = 2° 11' J ,, ^ A-oi. 1* Distances As73 | 5 Obs. | Diff. = o".3i2} ^^^ ^^<^"^*- Stars on the meridian, and admirably defined. Measures obtained with 327, and considered very satisfactory. Passy ; June 23, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 63° 7' np\7 Obs. I Diff. = 1° 30' > r>;n;^„,. Distance = i".339 | 5 Obs. j Diff. =o".3365 ^^"icuit. Observed with 327 ; stars on the meridian, but very unsteady. Mean Result. Position 6s° S^'np^ss Obs.) ; Distance i".42i (20 Obs.); Epoch 1835.45. These measures, compared w^ith those of 1823, give a motion of only —0° 10' instead of — 1° &, which calculation 340 Mr, South's re^examination of the apparent distances No. XVII. R. A. 15^ 18™ ; Decl. 38*^ I'N. ^/jtcBootis; I. 17; H. andS. 203. continued. would assign. The direction however is right ; and as the errors required to produce this discrepancy would be very small, we may combine both series of observations for a mean epoch, which will give. Epoch 1824.61 ; Position 63° SG> up. Difference of Declination of /x Bootis and of the larger of the two stars forming the close double star which is sf it, Passy ; June 21, 1825 ; Seven-feet Equatorial. Difference of declin. = i' 47". 3 14 | 6 Obs. | Diff. = o".793. Observed when on the meridian with 327 ; but the stars very unsteady. Passy ; June 23, 1825 ; Seven-feet Equatorial. Difference of declin. = \' ^y",ig^ | 7 Obs. | Diff. = i".io6. Observed on the meridian with 327 ; the stars very unsteady. Passy ; July 2, 1825 ; Seven-feet Equatorial. Difference of declin. == i' 47'.6io | 7 Obs. | Diff. r:o".336. Observed on the meridian with 181, which power during twilight completely separates the two stars of the close double star. Observed without artificial illu- mination of the micrometer wires ; stars very steady ; measures satisfactory. Mean Result. Difference of Declination i'47"-S77(2oObs.); Epoch 1825.48. The mean of 12 observations taken July 9, 1823, with the Five-feet Equatorial, was 1' 46^.962, differing only 0^.415 from the present determination. and positions of 36 double and triple stars, &c. 34 1 No. XVIII. R. A. 15^^ eS"- ; Decl. 11° 9' N. S Serpentis ; I. 42 ; H. and S. 205. Double ; 8th and 9th magnitudes. Passy ; April 3, 1825 ; Seven-feet Equatorial. Position = 74° s' sp 7 Obs. i DifF. rr 2** 22' ) Unsteady, and ill Distance = 3".287 5 Obs. J Diff. = o".3845 defined. Observed with 413, when 20 minutes east of the meridian. Passy ; June 12, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 70° 41' sp | 7 Obs. ) DifF.=3° 4'. Rather diiEcult. Observed on the meridian ; but the stars are so extremely unsteady, that to obtain measures of distance is impracticable. Passy ; June 13, 1825 ; Seven-feet Equatorial. 8 th and 9th magnitudes. Position = 68° 32' sp I 7 Obs. Distance = 3^325 j 5 Obs. Observed with 327 on the meridian. Night rather favourable. Passy; June 14, 1825 ; Seven-feet Equatorial. Small, decidedly light blue. SI ;o°.So's} Tolerably steady. Position = 70° 53' sp Distance = 3".39o 7 Obs. Diff. = 0034' I With ,81. 5 Obs. Diff. =0.3603 I. Observed on the meridian ; stars rather unsteady. Passy ; June 16, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 69<' 35' sp 7 Obs. 1 Diff. = z° 10' ) xxr't^u tC Distance = 3".268 5 Obs. | Diff. = o".2i65 ^"" *** Passy ; June 19, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 69® 23' sp I 7 Obs. Distance =: ^".ojz \ 5 Obs. 211= S.?6}R^*er steady. Observed with 327 on the meridian. Night tolerably favourable. Mean Result. Position 69° 49' sp (35 Obs.); Epoch 1825.46. Distance 3^268 (25 Obs.); Epoch 1825.42. In taking the mean, the position observed April 3 is rejected. 342 Mr. South's re-examination of the apparent distances No. XVIII. R. A. 15^ 26"^ ; Decl. ii° 9' N. ^ Serpentis ; I. 42 ; H. and S. 205. continued. Either there is a considerable error in these or the mea- sures of 1821, or the result is unfavourable to the motion assigned to this star, as, instead of advancing 3° in its appa- rent orbit, it seems actually to have receded nearly 50'. Further observations must elucidate this difficulty. (H.) No. XIX. R. A. 15*^ 54°^; Decl. 10° 52' S. 0 Scorpii ; I. 33 and II. 20 ; H. and S. 216. Double ; 6th and 9th, or 10th magnitudes ; small, decidedly blue. Passy ; June 14, 1825 ; Seven-feet Equatorial. Position = 12° 36' «/ 7 Obs. DifF. = i° 37' ^ ^t . j Distance = 7".290 5 Obs. DiflF. = o".745 J ^^^teady. Observed on the meridian with 181. Passy; June 16, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position =: 14° 27' n/ 7 Obs. I Diff. = 2° 14' ) tt . j Distance =6^946 5 Obs. | Diff. = o".6j3 } ^"5^^^^^ Observed with i8i ; stars on the meridian. Passy; June 17, 1825; Seven-feet Equatorial. 6th and 9th magnitudes. Position == 13° 59' nf 7 Obs. Diff. = 1° 52' ) Unsteady, but well Distance = 6".975 5 Obs. Diff. =: o".24o 3 defined. Observed on the meridian with 181. Passy ; June 18, 1825 ; Seven-feet Equatorial. 6th and 9th magnitudes. Position =12° 27' nf | 7 Obs. | Diff. = 2° 23'. Tolerably steady. Observed by Mons'. Arago on the meridian, with a power of 181. Mean Result, Position 13° ^^ nj\ Distance 7".o7o; Epoch 1825.46. and positions of $6 double and triple stars ^ ^c, 343 No. XIX. R. A. 15^ 6^ ; DecL 10° 52' S. I Scorpii ; I. SS and II. 20 ; H. and S. 216. continued. * Triple ; A and B equal ; each of the 7th magnitude ; C of the 9th. Measures of the close pair A B. Passy ; June 19, 1825 ; Seven-feet Equatorial. Position =: 84° 43' sfor np \ 5 Obs. j DifF, = 2" 3'. Unsteady. In the former communication | Scorpii was only observed as a double star ; Sir W. Herschel however having described it as triple, I have examined it several times with reference to this point ; but the extreme unsteadiness of the stars, parti- cularly those of low altitudes, during several weeks past, has precluded the use of high magnifying powers. This even- ing the stars being more tranquil, a power of 327 was applied, and an elongation of the large star was at times suspected : 413 confirmed the suspicion, but was inadequate to separate the two stars. The angles here given were obtained with 513, with which the discs of the stars seemed in contact ; but their extreme unsteadiness under this magnifying power rendered all attempts to procure measures of distance abortive ; and the position, from this circumstance, must be regarded with some distrust. The stars have the same colour, and were observed on the meridian. Passy ; June 21, 1825 ; Seven-feet Equatorial. Each of the 7th magnitude. Position = 81° 48' np ov sf\ 5 Obs. | DifF. = 6° 22'. Extremely difficult. Three of the angles were gotten with 512, the other two with 413. The extreme unsteadiness of the stars rendered the observations so unsatisfactory, that I consider them as little else than approximations. Observed on the meridian. 344 Mr. South's re-examination of the apparent distances No. XIX. R. A. 15' 54™; Decl. 10^52 S. 2 Scorpii ; I. 33 and II. 20 ; H. andS. 21^. continued. Measures of the close pair A B. Passy ; June 23, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position = 80° 14'*/ Distance r= i'.o'^z 7 Obs. I DifF. = 1° 58' ) „ ^ , ,._ ,, 6 Obs. Diff. = o"lu \ Extremely difficult. •4323 Observed on the meridian with 413 ; stars unsteady; yet I never saw them so well defined. Passy ; June 29, 1825 ; Seven-feet Equatorial. 6th and 6| magnitudes. Position = 8/2° 26' sf | 7 Obs. Distance = i".272 | 5 Obs. Sff:i;"/j; }!>»-'• Observed on the meridian with 413 ; stars perfectly round : a black division be- tween them seen distinctly. The measures 1 consider good, and were gotten with less difficulty than either of the preceding sets. Evening very favourable ; stars unusually steady. Passy ; June 30, 1825 ; Seven-feet Equatorial. 7th and 7i magnitudes. Position r: 82° 57' sf\ 7 Obs. [ DifF. = 3<^ lo'. Extremely difficult. Observed when a few minutes east of the meridian with 413 ; stars at times well defined : light clouds and extreme unsteadiness, render it impossible for me to procure measures of distance, nor can any observations of A, or B, with the more distant star C, be obtained. Passy ; July 2, 1825 ; Seven-feet Equatorial. 7th and 7? magnitudes. Position = 82° 48' sf\ 7 Obs. DifF. = 3° 21' > tt ^ , ' Distance =i".678 | 5 Obs. DiiF. =0". 192} Unsteady. Observed with 413, when 5 minutes east of the meridian; angles very difficult ; distances extremely difficult. Passy; July 4, 1825; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 79° 33' sf\ 7 Obs. I DifF. = 3° 45' \ unsteadv Distance = i".394 | 5 Obs. | DifF. = o".24o j ^^"^^ unsteady. Observed when 10 minutes west of the meridian with a power of 413 ; measures very difficult. and positions of 36 double and triple stars y &c. 345 No. XIX. R. A. 15^ 54" ; Decl. 10° 52' S. J Scorpii; I. 33 and II. 20 ; H. andS. 216. continued. Measures of the close pair A B. Passy; July 8, 1825 ; Seven-feet Equatorial. 8th and 85 magnitudes. Position = 81° 34' sf 7 Obs. I Diff. = 5;, 13' \ Very unsteady. Distance =: I '.477 5 Obs. [ Diff. = 0.1923 ^ ' Observed by twilight with 413, when 15 minutes east of the meridian. Measures very difficult. Measures of A C. Passy ; June 23, 1825 ; Seven-feet Equatorial. Positions 90 3^/ „f j 7 Obs. Diff.= 2° 19' ) Very difficult. Distances: 7 .043 5 Obs. Diff.= 0.168) ' Observed with 413 ; but the measures are very difficult, because the distant blue star C does not bear so high a magnifying power ; indeed it is so very indistinct* that it is seen only with great attention. Passy ; June 29, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position = 8° i' n/ 1 7 Obs. j DifF. = 1° 8'. Remarkably steady. Observed when 10 minutes west of the meridian with 413 ; the measures are dif- ficult, because the star C is extremely indistinct with this power. 1 think the measures very good, Passy ; July 2, 1825 ; Seven-feet Equatorial. 7th and 10| magnitudes. Position =0° ly'nf] 7 Obs. DifF. = 1" 47' ) t7 ^ , j-a:^ 1.. Distance = 6".857 ^^ | 5 Obs. Diff. = o".769l Extremely difficult. Observed when 10 minutes west of the meridian with 327, with which the discs of the two stars A and B seemed in contact : variable refraction prevented mc using a higher power : the stars were at times well defined. Passy ; July 4, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. Position = 8° 49' nf | 7 Obs. { Diff. = 2° o'. Rather unsteady. Observed by twilight with 181, which sufficiently separated the two discs of the close pair A B ; stars 20 minutes east of the meridian at the time the measures were taken. MDCCCXXVi. yy 346 Mr. SouTH*s re'examination of the apparent distances No. XIX. R. A. 15*^ 54"^ ; Decl. io° 52' S. J Scorpii ; I. S3 and II. 20 ; H. and S. 216. continued. Measures of A C. Passy ; July 8, 1825; Seven-feet Equatorial. 7th and 10th magnitudes. Position = fzy' nf 7 Obs. j Diff. = 1° 24' 1 y ^j^ j Distance = 6".gBi 5 Obs. | Diff. =z o .505 > ' Observed with 413. Stars at times well defined, but very unsteady. Passy ; June 29, 1825 ; Seven-feet Equatorial. Measures of B C. 6 J and 10th magnitudes. Position = 17* 25' nf\ 7 Obs. J DifF. = 4° 15'. Very difficult. Observed when 20 minutes west of the meridian with 41 3 ; the position of B C is outained with more difficulty than that of A C ; and perhaps on this account the observations of the latter are scarcely so much to be relied upon, as those of the former. Passy ; July 2, 1825 ; Seven-feet Equatorial. 74 and lOj magnitudes. Position = 18° 16' n/ 1 7 Obs. | DifF. = 2° 10'. Extremely difficult. Observed on the meridian with 327 ; stars very unsteady. Passy ; July 4, 1825 ; Seven-feet Equatorial. 8| and 10th magnitudes. Position =: 17* 53' «/ 1 7 Obs. ] DifF. = 4" 59'. Very difficult. Observed with 327 when on the meridian; stars extremely unsteady. Passy ; July 8, 1825 ; Seven-feet Equatorial. 8th and 10th magnitudes. Position = 16° 28' nf \ 7 Obs. | DifF. = 1° 25'. Very difficult. Observed when 10 minutes west of the meridian; stars very unsteady. and positions of 36 double and triple stars ^ &c. 347 No. XIX. R. A. 15^ 54™ ; Decl. 10° 52' S. I Scorpii ; I. 33 and II. 20 ; H. and S. 216. continued. Mean Result. C Position 81** 54' sf (52 Obs.) ; Epoch 1825.49 ; °*^'^' (Distance i".s58 (26 Obs.); Epoch 1825.50. of A C. Position 9° 3'nf(s5 Obs.); Distance 6".96i (15 Obs.); Epoch 1825.50. of BC. Position 17** 30' w/(28 Obs.); Epoch 1825.51. The observations of A C when seen only as a double star, are not included in the mean result. Not the slightest alteration appears to have taken place in the relative position or distance of the close stars. The angle measured by Sir W. Herschel in 1782 was 82° 2' 5/, differing only 6' from the present ; while the interval, esti- mated at ^ or -J of a diameter, would correspond to a distance of about if. (H.) No. XX. R. A. 16^ 4" ; Decl. 14° 1' N. 49 Serpentis ; I. 82 ; H. and S. 221, Double ; 8th and 8|- magnitudes, Passy ; April 3, 1825 ; Seven-feet Equatorial. Position = 48° 38' np Distance z= 3".734 7 Obs. DifF. = 4° 0' 7 ^, , . . 5 Obs. DifF. = J'.36o 1 Observed with 41 3. Stars at times well defined, but unsteady. Passy ; June 13, 1825 ; Seven-feet Equatorial. 8th and 8| magnitudes. DifF.=:o".336jU"^*"^^y' Position = 47<> 43' np I 7 Obs. Distance = 3". 330 | 5 Obs. Observed on the meridian with 327 j pretty well defined. Passy; June 16, 1825 ; Seven-feet Equatorial. 8th and 8 J magnitudes. Position = 47° 30'np\7 Obs. I DifF. = 2° 29' | Unsteadv Distance = 3".44o | 5 Obs. | DifF. = o".244 \ "^^steaqy, Observed when on the meridian with i8i j tolerably good measurer. 348 Mr. South' s re-examination of the apparent distances No. XX. R. A. 16^ 4" ; Decl. 14° 1' N. 49 Serpentis ; I. 82 ; H. and S. 221. continued. ,^ ^JPassy; June 19, 1825 ; Seven-feet Equatorial. . \ 8th and 8| magnitudes. Position = 48° s^'np\7 Obs. I DifF. = i° 28' 7 Tolerably steady Distance = 3".soo | 5 Obs. | DifF. = o".s29 j ^ oieramy steady. Observed on the meridian with 181 ; results satisfactory. Mean Result. Position 48° 10' np (20 Obs.); Distance 3".5oi (20 Obs.); Epoch 1825.41. The change in this star since the last observations is such as to confirm the direction of its motion ; but the quantity is more than calculation w^ould give, amounting to no less than 6° 13', instead of 1° 6'. This renders it probable that the measures of 1823 are erroneous,* and that Mr. Struve's measure in 1820 (46'* ss* np) is entitled to greater confi- dence. The former rest on the observations of one night ; and long experience has now shown, that this can never be fully depended on. (H.) No. XXI. R. A. 16^ 8°^ ; Decl. 34** 20' N. .• r. ii;:, or njT Distance = 4".578 7 Obs. 5 Obs. cilio-jy Tolerably steady. Observed when 45 minutes east of the meridian ; more than half of the object-glass is rendered useless by the interference of the observatory timbers. and positions of sQ double and triple stars y^c» 35S No. XXIII. R. A. 17^ 3" ; Decl. 54° 43' N. /t* Draconis; II. 13 ; H. and S. 242. continued. Mean Result, Position 61° 2' sp or nf (ss Obs.) ; Epoch 1825.252 ; Distance 4*.330 (30 Obs.j ; Epoch 1825.47. The position of this star, as determined for the mean epoch 1820.97, is 6o°.29, or 60° 18' sp or nf (Phil. Trans. 1824, III. p. 271.) It is now 61° 2'. The change in 4.55 years is — 0° 44', instead of — 2° 36' y which a computation founded on a mean motion of — o*'.5792 per annum would give. The determination for 1820 can however hardly be relied on for so great a degree of exactness as to bring out a precise quantity. The correspondence in direction is all we can ex- pect, and is a satisfactory confirmation of the motion ascribed to this curious star. (H. ) No. XXIV. R. A. 1 7*^ 4"^ ; Decl. 26° 18' S. 36 Ophiuchi ; H. and S. 243. Triple ; A 6i, B 7th, and C 9th magnitudes. Measures of A B. 6^ and 7th magnitudes. Blackman-street ; June 28, 1824; Five-feet Equatorial. Position = 410 19' sp \ 5 Obs. [ Diff. = !<> 34'. Tolerably steady. Blackman-street ; July 12, 1824 ; Five-feet Equatorial. 6'th and 6^ magnitudes. Position = 41° 58' sp 5 Obs. I DifF. = 1° 31' ) „ . Distance = 5*. 195 5 Obs. ) DifF. = o".885 j Unsteady. Passy ; June 19, 1825 ; Seven-feet Equatorial. 6| and 7th magnitudes. Distance = 5'.26o [ 5 Obs. | Diff. = o*.505. Very unsteady. MDCCCXXVI. Z Z 354 Mr. South' s re-examination of the apparent distances No. XXIV. R. A. 17^ 4™ ; Decl. 26' 18' S. 36 Ophiuchi ; H. and S. 243. continued. Passy ; July 2, 1825 ; Seven-feet Equatorial. 6^ and 7th magnitudes. Distance tz s".i4S | 5 Obs. { Diff. = o".48i. Very unsteady. Passy ; July 24, 1825 ; Seven-feet Equatorial. Gl and 7th magnitudes. Position = 41° 18' « j9 I 5 Obs. \ Diff. = 2^ 30'. Tolerably steady. Measures of A C. Blackman-sti'eet ; July 12, 1824 ; Five-feet Equatorial. 6th and 9th magnitudes. Position zr i6° 6' np Distance = 3' 1 4^^444 3 Obs. 3 Obs. Diff. = 0° 30' ) TT * J Diff=i".863lU"^*^^^y- Passy ; July 2, 1825 ; Seven-feet Equatorial. 7th and 9th magnitudes ; small, blue. Position = 16^ X* np I 4 Obs. I Diff. =0° 30' ) ,. ^ _ , , , Distance = 3' ^6' .235 \ Obs. | Diff. =: o".6oi \ Extremely unsteady. Passy ; July 8, 1825 ; Seven-feet Equatorial. 7th and Qth magnitudes. Distance = 3' i4".924 | 7 Obs. \ Diff. = 2".236. Night become unfavourable. Passy ; July 20, 1825 ; Seven-feet Equatorial. 7th and 9 J magnitudes. Position =15° 56' np 1 5 Obs. Distance = 3' is".547 \ 6 Obs. Diff. =0054' \ ^r * J Diff.=:o".288iV^^""^*^^^y- Passy ; July 29, 1825 ; Seven-feet Equatorial. Difference of declination := 54".8o2 | lo Obs. j Diff. = z"»TiT- Observed when 3 minutes east and west of the meridian ; stars not steady. Passy; August 1, 1825 ; Seven-feet Equatorial. Difference of declination z^55".632 j lo Obs. J Diff. = i".75S. Observed on the meridian ; stars tolerably steady. Passy ; August 5, 1825 ; Seven-feet Equatorial. Difference of declination = 55".855 | 10 Obs. ) Diff. = i".563. Observed when 5 minutes east and west of the meridian; stars very unsteady, and C very faint. and positions of 36 double and triple stars, &c. 355 No. XXIV. R. A. 17^ 4" ; Decl. q^ 18' S. 36 Ophiuchi ; H. and S. 243. continued. Measures of B C. Pftssy; July 8, 1825 ; Seven-feet Equatorial, 74 and 9th magnitudes. Position =: 17° ^2' np \ 3 Obs. | DifF. = o^ 19'. Very faint. Night now so cloudy, that no more observations can be procured. Passy ; July 13, 1825 : Seven-feet Equatorial. 7f and 9th magnitudes. Position =1 1 7° 42' 74 p Distance = 3' I3".6i8 5 Obs. 5 Obs. DifF. = 0° 21' I ,r ^ , Observed within a few minutes on either side of the meridian. Passy ; July 14, 1825 ; Seven-feet Equatorial. 7th and 9th magnitudes. Position = 17° ^i' np I 5 Obs. 1 DifF. = 0° 14' ) Unsteadv Distance = 3' i2".75o c Obs. Diff. = o".50? 4 ^"steady. Observed when a few minutes east and west of the meridian. Passy ; July 18, 1825 ; Seven-feet Equatorial. 7th and 9^ magnitudes. Distance = 3' I4".i33 j 5 Obs. | DifF. = o".84i. Extremely unsteady. Observations taken when the stars were 15 minutes west of the meridian. Passy ; July 19, 1825 ; Seven-feet Equatorial. 7th and 9th m^nitudes. Distance =: 3' 14". 159 | 6 Obs. | Diff. = o".962. On the meridian. Stars so extremely unsteady, that I could not use a higher power than 157. Mean Result. r Ar> i Position 41° 32' sp (15 Obs.) ; Epoch 1824.86 ; of Ab. j^£)istance 5".2oo(i5 Obs.); Epoch 1825.17. of AC. Position 16° 1' np (12 Obs.); Epoch 1825.19 ; Distance 3' 15".252 (19 Obs.) ; Epoch 1825.27. fRP {Position 17° 41' «/> (10 Obs.); Epoch 1825.53 ; ot 15 U |j)igtaj^ce 3' 13".689 (21 Obs.); Epoch 1825.54. of A C. Difference of declination 55".430 (30 Obs) ; Epoch 1825.59. 356 Mr. South's re-examination of the apparent distances No. XXIV. R. A. 17' 4- ; Decl. 26° 18' S. 36 Ophiuchi ; H. and S. 243. continued. Our former measures gave, of AB. Position 42° 41' sp or nf; Distance 5". 546 ; of the distant star C. Position 19° 5' np ; Distance 3' o*735. The position of C was taken relatively to the star B, and is not materially in error; the distance however is decidedly wrong, and must have arisen from erroneous reading of the micrometer. Observations to connect the star A, or the northern of the two stars of 36 Ophiuchi, with the star 30 Scorpii. Passy ; July 21, 1825 ; Seven-feet Equatorial. Position = Distance = i 14° 25'»/; single measure. \ Unsteadv 12' 7".940 I 2 Obs. I DifF. = i".o82 5 ^J^steady. Observed with 157, when 15 minutes east of the meridian; some slight inaccu- racy may be apprehended, as the wires when separated to so great a distance are not quite free from parallax. Passy ; July 23, 1825 ; Seven-feet Equatorial. Position = 14° 27' nf I 5 Obs. Distance = 12' 5". 590 | 5 Obs. ^iff: = 2''.ofQ| Tolerably steady. Diff. = 2".oi95 Observed with a power of 92, when within 5 minutes on either side of the meridian Passy ; July 28, 1825 ; Seven-feet Equatorial. Position = 14° 28' nf I 5 Obs. Diff. = 0° 12 | ^,. , Distance = 12' 4".20i | 5 Obs. DifF. = o".84i ] ^^^^"^V- Observed on the meridian, but the distance is too great for accuracy. Passy ; August 1, 1825 ; Seven-feet Equatorial. Distance = 12' 5".48o | 7 Obs. [ DifF. = i".875. Tolerably steady. Observed when 10 minutes west of the meridian with 92. Mean Result. Position 14" ^1' nf'. Distance 12' 5".i36; Epoch 1825.57. In taking the mean, the distance observed July 21 is rejected. and^ positions of 36 double and triple stars, &c. 357 No. XXIV. R. A. 17H" ; Decl. 26° 18' S. 36 Ophiuchi ; H. and S. 243. continued. Observations to connect the star A, or the northern of the two stars of 36 Ophiuchi, with the star 30 Scorpii. Passy ; July 8, 1825 ; Four-feet Transit Instrument. Diflference of R. A. == o' 52" .40 (3 Obs.) Unsteady. Passy ; July 13, 1825 ; Four-feet Transit Instrument. Difference of R. A. =:©' $2"./^^ (4 Obs.) Unsteady. Passy ; July 14, 1825 ; Four-feet Transit Instrument. Difference of R. A. = o' 5 2".47 (4 Obs.) Unsteady. Passy ; July 8, 1 825 ; Seven-feet Equatorial. DiflFerence of declination — 3' i",438 db single observation. Become cloudy. Passy ; July 18, 1825 ; Seven-feet Equatorial. Difference of declination — 3' i".ogi (6 Obs.) Diff. = 1 '.683. Observed on the meridian ; stars very unsteady. Barometer 30.05 inches ; Thermometer 84°. Passy ; July 19, 1825 ; Seven-feet Equatorial. Difference of declination =: 3' i".745 (7 Obs.) Diff. := 3'''775« Observed on the meridian ; the stars so extremely unsteady, that I could only use a magnifying power of 157. Barometer 30.30 inches j thermometer 84°. Passy ; July 20, 1825 ; Seven-feet Equatorial. Difference of declination = 3' 2".\^z (6 Obs.) Diff. =: ^''.yij. Observed on the meridian j stars extremely unsteady. Barometer 30.34 inches. Thermometer 83°. Mean Result. Difference of Right Ascension (in time) o' 52^.444 (11 Obs.) ; Epoch 1825.53. Difference of Declination 3' 1^.653 (20 Obs.) ; Epoch 1825.54^ 358 Mr. South's re^examination of the apparent distances No. XXIV. R. A. 17** 4" ; Decl. e^ i8' S. 36 Ophiuchi ; H. and S. 243. continued. Observations to connect the star A, or the northern of the two stars of 36 Ophiuchi, with the star A, or the southern of the two stars of s8 Ophiuchi. Passy ; July 21, 1825 ; Four-feet Transit Instrument. DiJfFerence of R. A. = 2' ii".78o (5 Obs.) Unsteady, and 38 very faint. Passy ; July 23j 1825 ; Four-feet Transit Instrument. Difference of R, A. c= 2' 1 1".925 (4 Obs.). Very unsteady, and 38 faint. Passy ; July 25, 1825 ; Four-feet Transit Instrument. Difference ofR.A. :^ 2',il".640 (5 Obs.) Tolerably steady. Passy ; July 27, 1825 ; Four^feet Transit Instrument. Difference of R. A. =2' ii".720 (5 Obs.) Tolerably steady. Passy ; July 21, 1825 ; Seven-feet Equatorial. Difference of declin. = 5' 25".o96 (4 Obs.) Very unsteady. Diff. = i''.Si^. Not more than 6 minutes on each side of the meridian when observed. The ■ ; v.'iihi Barometer standing at 30.30 inches ; Thermometer 74°.5. Passy ; July 24, 1825 ; Seven-feet Equatorial. Difference of declination = 5' 24".o8i (5 Obs.) Diff. =4".o87. Observed when within 'lo minutes on either .aide of the meridian j stars tolerably steady. Passy ; July 25, 1825 ; Seven-feet Equatorial. Difference of declination = 5' 2^"./[.$g (5 Obs.) Diff. = i".467. Stars tolerably steady ; and when observed not more than 10 minutes east and west •of the meridian. Barometer 30.10 Inches; Thermometer 70". Passy ; July 27, 1825 ; Seven-feet Equatorial. Difference of declination z=. 5' 24". 004 (4 Obs.) Diff. = 2".^y6. Observed when 8 minutes on either side of the meridian. Tolerably steady. Mean Result, Difference of Right Ascension (in time) 2' ii''.758 ( 19 Obs. ) ; ©ifFerence (Of Declination 5' 24".394 (18 Obs.) ; Epoch 1825.56. and positions of 36 double and triple stars, &c 359 No. XXIV. R. A. 17^ 4"^ ? Decl. 26° 18' S. S6 Ophiuchi ; H. and S. 243. continued. In the former Paper the attention of astronomers was par- ticularly directed to this star, on account of a considerable proper motion which it was supposed to have, in common with a very distant star 30 Scorpii ; and as the point is a very interesting one, the preceding observations were made, with a view of placing the matter beyond doubt : a few comments upon them will perhaps be not without their use. ^A 38 Ophiuchi •B B •A s6 Ophiuchi • so Scorpii In the above diagram, the close stars of A B of 36 Ophiuchi are represented relatively to the star C, to 30 Scorpii, and to A B of 38 Ophiuchi, as seen in the telescope ; C preceding A of 36 to the north, and A of 38 following it to the south. First, as it regards Declination. If any proper motion of 36 exist in this direction, (supposing the star C at rest) the effect of it will be to increase, or diminish 36o Mr. South' s re-examination of the apparent distances No. XXIV. R. A. 17*^4'"; Decl. 26° 18' S. 36 Ophiuchi ; H. and S. 243. continued, the difference of declination of AC; and should A of 38 be fixed, the difference of declination of A of 36, and A of 38, will also be increased or diminished. By this mode of observing we have two chances of detecting proper motion, each of which will afford a verification of the other ; for suppose the star A of S6 Ophiuchi to have a motion toward the south, say at the rate of one second per annum, then will the dif- ference of declination between it and the star C to the north of it, be increased annually by one second ; but that which increased the difference of declination between these two stars, should diminish the difference of declination between A of sQ, and A of 38 Ophiuchi ; and if our observations be correct, the increase of difference on the one hand, should be exactly equal to the decrease of it, on the other ; and vice versa, should the proper motion of A of 36, carry it toward the north. Secondly, in Right Ascension. Suppose the proper motion of A of 36 to be toward the west annually one second, the result will be, to lessen the difference of right ascension of it, and of the preceding star C, and at the same time to augment the difference of right ascension between A of 36, and A of 38 ; and, as before, the decrease in the one instance, should be equalled by the increase in the other ; and if the proper motion of A of S6, take an easterly direction, it will be detected by conse- quences opposite to those just described, but offering similar verifications. t^:i and positions 0/36 double and triple stars, &c. 361 ^o..^;x:^lY. R. A. 17^^ 4" ; Decl. 26° 18' S, 36 0phiucni; H. and.3. 243. continued. In the case of 61 Cygni, by following a similar mode of observing, (but using six stars of comparison instead of two,) I satisfied myself in a very few monthsy of the enormous proper motion of that extraordinary double star. To those who may feel disposed thus to attack proper motion, I would hint, how indispensable it is, that their Equa- torial should be well clamped, and that they should wait during the observations of difference of declination, till the earth's diurnal motion bring each of the following stars, opposite that part of the wire where the bisection of the first star was made ; the results will then be charged with no instrumental error, which it is in their power to avoid : the observations also should be conducted as nearly on the meri- dian as possible. '^'^ ' When the above was written, I was not aware that the. star 38 Ophiuchi had been observed since the time of Flam- steed ; on examining however Piazzi's catalogue, I find that it stands there under the name of 3 1 Scarpa, and that its place has been determined by 19 observations of that emi-- nent astronomer ; perhaps therefore some light may at the present time, be thrown upon the subject under consideration ;^ but some corrections will be needed by our observations, to render them comparable with those, to which we are alluding. The star 36 Ophiuchi is composed of two stars of nearly equal magnitudes, and distant from each other 5".2oo ; whe^i ther Bradley's instruments showed it double, does not appear; nor from Piazzi's catalogue, does it seem that he saw it otherwise than as a single star ; hence it is fair to MDCCCXXVI. 3 a 362 Mr. South's re-examination of the apparent distances No. XXIV. R. A. 17^ 4" ; Decl. 26** i8' S. 36 Ophiuchi ; H. and S. 243. continued. suppose, that the star was by one and the other observed as single ; our observations therefore must be corrected by half the difference of declination, and by half the difference of right ascension, which with the preceding distance, and position 41° 32' will be i".724 in declination, and i".946 on the parallel, equal to o".i47 of right ascension in time. For the star 38 Ophiuchi no correction of this sort will be required : its smaller star was certainly neither seen by Bradley nor by Piazzi ; and its magnitude, even were it at the time closer than it now is, would not sensibly alter the apparent centre of the disc of A of 38. But the differences of declination observed by us are un- corrected for refraction : the necessary equations being appHed, we get, Diff. of decl. of A of 36 Ophiuchi & of 30 Scorpii 3' 2".403 &Aof 38 Ophiuchi 5' 25". 764; and when the corrections to reduce these results to observa- tions of the centre of the two stars of s6 Ophiuchi are applied, the quantities become 3' 4^.127 and 5' 24*.o4o for the differences of declination ; and for differences of right ascension (in time) 5^" -591 and 2' ii".905 respectively. , Now by Bessel's proper motion,* the difference of declina- tion of 36 Ophiuchi and of 30 Scorpii, Epoch 1825.57, should be 3' 4 '.930, differing with our determination only 8-tenths of a second : hence in declination, the two stars have either the same, or no proper motion. But Bessel does not give the proper motion in right ascension, for it appears that BRADLEY-f did not observe the * Vide Fundam. Astronom. page 311 f In Bradley's published observations I have not met with any observed R. A. of 30 Scorpii, nor have I found any observation of 38 Ophiuchi, in the manuscript ' and positions of s6 double and triple stars, &c. S^S No. XXIV. R. A. 1 7^^ 4™ ; Decl. 26^ 1 8' S. 36 Ophiuchi ; H. and S. 243. continued. H transits of both stars ; Piazzi however, by a comparison of his own observations with those of preceding astronomers, assigns to them quantities, which for 1825.57 would give difference of R. A. (in time) 52".5o, agreeing with our determina- tion to 9-hundredths of a second ; hence also in R. A. as well as in declination, they have, if any, the same proper motion. If however the proper motions attributed to them be cor- rect, and if 7ione be enjoyed by A of 38 Ophiuchi, the differ- ence of declination between 36 and 38 should be 5' 23",o73, differing not one second from our determination : and if the proper motion in right ascension attributed to 36 be correct (the star 38 being fixed), the difference of R. A. (in time) be- tween them should be 2' 11". 76 orAy fourteen hundredths of a second, at variance with our observations ; quantities which may be very fairly attributed to errors of observation. Hence it follows, that the two stars 36 Ophiuchi and 30 Scorpii, although distant from each other more than 12 minutes, are journeying together through space ; and that the annual proper motions (i".0756 and i".ii55 toward the south, and o".59 and o".58 toward the west), assigned to them, are true. From the above investigation we also learn, that the star 38 Ophiuchi has no sensible proper motion ; consequently the observed increase of distance between it and the small star,* if it exist, must probably be sought for, in some pecu- liarity of the latter. -^ mass of his observations, (copied from the original possessed by the Unirersity of Oxford,) by Gael Morris, and now in the library of the Royal Society : that any observation of this illustrious Astronomer, " le Modele des Observateurs" of La Place, and whose observations, (in the emphatic language of the same Philosopher) constitute " I'^poque d'ou Ton doit partir maintenant, dans les recherches deli- cates de la science," should be recorded only in perishing manuscript, is to be hoped in these enlightened times, will not remain long an object of regret to Astronomers. * Referred to in page 209, 364f Mr. South's re-examination of the apparent distances No. XXV. R. A. 1 7^ 8- ; Decl. ss*' s' N. ^ Herculis ; V. i ; H. and S. 246. Double ; 4th and 10th magnitudes ; small, blue. Passy ; June 21, 1825 ; Seven-feet Equatorial. Position = 83° 26' sf\ j Obs. I DifF. = i° 25' 7 ^t . . j Distance= z&'.si^ | 5 Obs. | DifF. = i".oioi ^°^ '^^^^y* Observed on the meridian ; night not very favourable. Passy ; June 30, 1825 ; Seven-feet Equatorial. 5th and 10th magnitudes. Position = 83° S^'sf\ 7 Obs. I DifF. = i<'3o' 7 ^t ,1 . j i Distance= zi".6s9 \ 5 Obs. | DifF. = o^Uj \ Unusually steady. - Observed on the meridian ; the small star is blue, and bears a very good illu- mination. The night is extremely favourable : in the results I have the greatest confidence. Passy ; July 1, 1825 ; Seven-feet Equatorial. 5th and 1 0th magnitudes. DifF. =oOci' 7 ,» ^ , DifF.=o".697r^''y^^^^^y- Position = 83° 42' sfi 7 Obs. Distance s= z&'.Sg^ \ 5 Obs. Small star decidedly blue, and bears a very good illumination. Observations made when on the meridian, and are extremely satisfactory. Passy; July 4, 1825 ; Seven-feet Equatorial. 5th and Qth magnitudes. Position = 83° 12' 5/1 7 Obs. Distances 26". 883 | 5 Obs. Diff = ^".43! } Tolerably steady. Observed when 25 minutes west of the meridian. Mean Result. Position 83* S3' ^/(28 Obs.) ; Distance 9,6". 69^ (20 Obs.) ; Epoch 1825.50. The change stated to have taken place in this star is con- firmed by the present observations ; according to which, compared with those of 1821, a motion of -1- 1° 23' in angle, and — 2". 1 75 in distance, has taken place since our former measures. This is a remarkable verification of the relative motion both in position and distance ; and as the change is contrary to what the presumed proper motion of the large star would alone produce, this star merits particular attention. (H.) and positions of 36 double and triple stars, (^c. $66 No. XXVI. R. A. 17^ 56™ ; Decl. 2° ss' N. 70 p Ophiuchi ; II. 4 ; H. and S. 258. Double ; 7^ and 8^ magnitudes. Passy ; April 3, 1825 ; Seven-feet Equatorial. Position = 55° 51' sf Distance =z 4". 843 7 Obs. [ Diff. = 2° 25' ) Unsteady. 6 Obs. ] Diff. = o'.553 j Difficult. Observed when 1* 40' east of the meridian; the angles are perhaps as good as can be expected at so great a distance from the meridian : the distances, on account of unsteadiness of the stars, were gotten with considerable difficulty, and probably are a little liable to suspicion. Passy ; May 3, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 52° 3' */ I 7 Obs. Position = 51° 57' sf \ 7 Obs. Diff. = 1° 4+' ) if hour east of the meridian. = i°43'5 a Diff. = i°4Vi a hour The first set obtained with 181 ; the second set with 413 ; the night unfavour- able ; the stars neither well defined nor steady ; indeed the weather is become very bad for delicate observations. Passy ; June 23, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position =58° 50' sf \ 7 Obs. | Diff. == 4° 58'. On the meridian. Stars extremely ill defined and very unsteady ; so much so that I do not consider the results entitled to the least confidence ; measures of distance altogether imprac- ticable ; the night is beautifully clear, not a cloud visible ; but the extreme unstea- diness of the stars obliges me to discontinue observing, although I do it with the greatest reluctance. Passy ; June 29, 1825 ; Seven-feet Equatorial. 7 J and 9th magnitudes. Position = 58° 15'*/ 7 Obs. I Diff. = i<»24' ) ^ ^, . ,. n;cfor, ." «.. -^ r nKc n;ff ' ,^. ^ On the meridian. Distance = 4"-874 S Obs. I Diff. = o".2645 Stars very steady and well defined ; small, certainly not blue ; measures are satisfactory. Passyj June 30, 1825 ; Seven-feet Equatorial. 71 and 8| magnitudes. Obs. I Diff. = 1° 36') ^ ,, Obs. I Diff. = o".432 J ^"^ '^^ meridian. Stars well defined and steady ; measures good. Position =57° 13' sf Distance =4".4i9 366 Mr. South's re-examination of the apparent distances No. XXVI. R. A. 17^ 56™ ; Decl. 2° 33' N. 70 p Ophiuchi ; II. 4 ; H. andS. 258. continued. Passy ; July 1, 1825 ; Seven-feet Equatorial. 8th and 8^ magnitudes. Position = 58° lo' */ 7 Obs. I Diff. = 1° 32 7^ ,, . ,. Distance = 5".iso *^ 5 Obs. | DifF. = o".72i j^^ *^^ meridian. Stars very steady and well defined j measures extremely satisfactory. Passy; July 2, 1825 ; Seven-feet Equatorial. 8^ and 9| magnitudes. Position = 58° 18' «/ 7 Obs. I DifF. = 2° 8' 7 ^t ^ ^ Distance = ^".gzg 5 Obs. | DifF. z= o".4o8 j ^ ^steady. Observed on the meridian ; stars tolerably well defined. Passy ; July 4, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 58° 7' «/l 7 Obs. I DifF. = 0° 38' ) tvt .\ j . Distance = 4'.sU I 5 Obs. j Diff. = o".264 J ^^^ '^^^^V' Observed when 8 minutes west of the meridian; pretty well defined. Passy ; July 5, 1825 ; Seven- feet Equatorial. 82 and 9| magnitudes. Position = 57° 32'*/ 1 7 Obs. Diff. = i°4i' ) ^ ,, .,. Distance = 4-.789 | 5 Obs. Diff. = o".48i } <^^ ^^^ meridian. Stars unsteady, and occasionally very faint ; light clouds passing over them. Passy ; July 13, 1825 ; Seven-feet Equatorial, 7^ and 8 1 magnitudes. Position = 57° 56' sf\ 7 Obs. Diff. = 2° 20' 7 t., . - , , Distance = i''.49i ^^ | 5 Obs. | Diff = o".3i2 { ^^^ ^^^ ^^^^^r- Observed when 10 minutes east of the meridian. Mean Result. Position 57° 48' 5/ (63 Obs.) ; Epoch 1825.48 ; Distance 4/' -763 (41 Obs.); Epoch 1825.48. In taking the mean, the observations of May 3 are rejected. J and positions of sS double and triple stars ^ ^c, 367 No. XXVI. R. A. 1 1^ 56"^ ; Decl. 2° 33' N. 70 p Ophiuchi ; II. 4 ; U. and S. 258 ; continued. Second Series. Passy ; August 16, 1825 ; Seven-feet Equatorial. 71 and 8| magnitudes. Position = 58° 38' V" f 7 Obs. I Diff. = 2° 37' ) „ , , Distance = 4".8i4 5 Obs. j DifF. = o".456 j ^^^ '*«**^y- Observed on the meridian. Passy ; August 17, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 58° 9' sf 7 Obs. DifF. = !<> 11' 7 ,, , . Distance = 4".779 5 Obs. | DifF. = o".505 j ^^^ ^^«*^y- Observed on the meridian. Passy ; August 20, 1825 ; Seven-feet Equatoiial. 8th and 9th magnitudes. Position = 58° 13' */ 7 Obs. I DifF. = i° c' > ^- Distance = 4".874 5 Obs. | DifF. = o".889 j ^^^ ^^^^^y* Observed on the meridian. Passy ; August 21, 1825 ; Seven-feet Equatorial. 7th and 8| magnitudes. Position = s80 41' sf 7 Obs. I DifF. = 1° 27' ) ,, Distance = 4".7i4 j 5 Obs. | DifF. = o".336l ^^^ ^^^^^y* ObseiTed on the meridian. Passy ; August 23, 1825 ; Seven-feet Equatorial. 7th and 8| magnitudes. Position = 58° 1/ */| 7 Obs. | DifF. = 2° 21' } ^, Distance = 4".s66 j 5 Obs. DifF. = o".2i6 ( ^°^ "^^^ ^*^**^y- Passy ; September 1, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 58° 32' sf I 7 Obs. I DifF. = 2° 58' > ^^ , , , , , Distance = 4".864 | 5 Obs. | DifF. = o".36ol tolerably steady. Observed by twilight, without artificial illumination, when 5 minutes east of the meridian. Mean Result. Position 58° 25' 5/(4^2 Obs.) ; Distance 4". 769 (30 Obs.) ; Epoch 1825.64. 368 Mn South' s re-examination of the apparent distances No. XXVI. R. A. 17^ 56" ; Decl. 2° 33' nI " 70 p Ophiuchi ; 11. 4 ; H. and S. 258 ; continued. The mean of both series, allowing each a weight propor- tioned to the number of measures, gives for the Epoch 1825.56 ; Position 58° 3' 5/(105 measures.) Distance 4^765 (71 Obs.) If now we collect all the observations made in the years 1821, 1822, 1823, and 1825, we find as follows : 1821.51 ; 66° 50' 5/; (Mean of Herschel's, South*s, and Struve's Obs. Phil. Trans. 1824. iii. p. 290. 1822.49 ; 65"" i sj\ H. and S. 1822, 1823.32; 63 25 sj\ H. and S. 1823. 1825.54 ; 58 3 sf\ S. ut supra. The intervals are 0.98, 0.83, and 2.22 years, and the Angles described respectively in them — i°.7i7, — i°.70o, and — 5°. 36 7, whence the angular velocities come out re- spectively— l°.75i, — 2^050, and — 2°.4i8, all of them greatly below what appears to have been the velocity up to 1820, and not differing more than might fairly be expected, considering the difficulty presented by the unequal size of the stars. The last determination, considering the great number of measures it rests upon, may be regarded as en- titled to great confidence, in spite of the discordant results of April 3 and May 3, 1825, which, however, whether rejected or retained, make little difference in the final mean. It was on these (unluckily), that the note at the end of the paper of J 824 was founded. The fact of a great diminution of angular velocity then in ^ and positions of s6 double and triple stars, ^c. 369 No. XXVI. R. A. 17^ 56"^ ; Decl. 2° ss' N. 70 p Ophiuchi ; II. 4 ; H. and S. 258. continued, this star can hardly be doubted. But as it is inconsistent with the laws of central forces that this should take place without a corresponding increase of distance ( for the angular velocity is inversely as the square of the distance in the ap- parent as well as in the real orbit, whatever be its position with regard to the line of sight), it becomes necessary to ex- amine more minutely into the distances at the different epochs. It will be observed, however, that in all the interval from 1781 to 1819 we find no measure of the distance, and that the maximum of angular velocity must have taken place somewhere in this interval. (See Phil. Trans. 1824. iii. p. 290-291.) In such a case we must recur to estimations in diameters, though necessarily less to be depended on than positive measures. On re-examining Sir W. Herschel's MSS., we fortunately find the following observations, which throw considerable light on this point, and in some measure supply the deficiency of measures. It will be recollected that his measures of distance are always supposed to include both diameters of the stars measured. " October 27, 1779. 3".593. They are very difficult to " measure, and for that reason I join also an exact " estimation by the eye. The vacancy between them " is 2|- diameters of the largest — certainly more than " two and less than 3. The smallest may be about i " or I of the diameter of the other. They are exactly " in the equatorial motion ; the largest goes first. The " situation I took by letting them run along the hair." MDCCCXXVI. s b S70 Mr. South' s re-examination of the apparent distances No. XXVI. R. A. 17^ 56"^ ; Decl. 2° 53' N. 70 p Ophiuchi ; II. 4 ; H. and S. 258. continued. " May 11, 1780, 5".468 ; but very difficult to take, and " therefore not much to be depended on/'. . . . " I am " apt to believe that this method generally gives the " distance too large." " June 19, 1780. If diameter, or between i|- and 1^ by " very exact estimation By measures ^'.si5." " August 28, 1780. 4".53i. Almost 2 diameters of the " largest, which is the preceding star. The difference " in size almost 2 to 1, or 1^ to 1." " May 27, 1781. Much above 2 diameters of the largest " with 460." " April 28, 1783. Above 2 diameters.*' From all these observations, it is clear that the interval between the stars about the year 1780 could not be less than 2 diameters, and by a mean of all the estimations, must have been about this quantity, or rather more than less. The small star being taken at 0.6 of the diameter of the large, the distance of their centres must have been 2.8 D, and the distance, including the diameters, 3.6 D. Now as this distance by the mean of all the measures, was 4'^492, we have D = i".25 and 2.8 D = 3".5oo. Again ; we find the following observation, the only one which occurs in the interval in question. *' June 3, 1804. About i^ diameter of L." This would give for the distance between the centers 2.05D = 2".5625. So far then as estimations by diameters can go, these and positions of 36 double and triple stars , ^c. 371 No. XXVI. R. A. 17^ SGT ; DecL 2*=^ 33' N. 70 p Ophiuchi ; II. 4 ; H. and S. 258. continued. observations establish the point in question, viz. that a very considerable diminution of distance really accompanied the great increase of angular velocity, and that as the velocity has since diminished, the distance has actually undergone a corresponding augmentation. It is much to be regretted that the opportunity of observing this interesting object in perihelio has been lost. ( H. ) No. XXVII. R. A. i8J» 18"^ ; Decl. 0° 5' N. 69 Serpentis (d); I. 12 ; H. and S. 268 ; Double ; 7 and 9j- magnitudes. Passy; July 12, 1825 ; Seven-feet Equatorial. Position = 50° 12' np I 7 Obs. | DifF. = 2° 43' 7 tt .. a j mi j £ j Distance = \'.^S6 "^ | 5 Obs. | Diff. = o".6oi } Unsteady and ill defined. Observed when 10 minutes east of the meridian. Passy ; July 14, 1825 ; Seven-feet Equatorial 7th and 10th magnitudes. Position = 47» 18' no 1 7 Obs. DifF. = 1° 17' ? u .u A-tr. 1. Distance = 4^369 | 5 Obs. DifF. = o".384 \ ^^^^^' ^'^^''^^' Observed when 10 minutes east of the meridian. Stars not always well defined, but are tolerably steady. Passy ; July 15, 1825 ; Seven-feet Equatorial. 7i and 10th magnitudes. Position = 49° 9' ap j 7 Obs. Distance = 4".338 ( 5 Obs. Diff! - o°.6oi } ^^^^^^ ^^&cu\t. Observed on the meridian. Stars neither steady nor well defined. The smaller one is blue. Position = 48° ig' np Distance = 4".347 Passy ; July 18, 1825 ; Seven-feet Equatorial. 7i and 10th magnitudes. 7 Obs. 5 Obs. Observed on the meridian. Diff = o'' 601 \ ^^^*her steady nor well defined. 373 Mr. South's re-examination of the apparent distances ^o. XXVII. R. A. 18^ 18- ; Decl. o° 5' N. 59 Serpentis (d) ; I. 12 ; H. and S. 268. continued. Passy ; July 19, 1825 ; Seven-feet Equatorial. 7th and 10th magnitudes. Position = 47° 54' n;? Distance = 4".784 7 Obs. S Obs. DifF. = 305'),, ^ . Diff. = o".4o8P^''y"°^*^^^y- ' Mean Result. Position 48° s^np (s5 Obs.); Distance ^'.^6s (25 Obs.); Epoch 1825.54. These observations compared with those of 1822 certainly afford no corroboration of the idea of an approach of these stars towards each other. ( H. ) No. XXVIII. R. A. 18^ 21- ; Decl. 58° 42' N. 39 Draconis ; I. 7 ; H. and S. 269. Triple ; A of the 5th, B of the 10th, and C of the 8th magnitudes. Measures of A B. Passy ; July 14, 1825 ; Seven-feet Equatorial. Position = 84* 48' nf I 7 Obs. I DifF. = 3° 1 1' > njffirnlf Distance = 3".782 | 5 Obs. \ DifF. = o".937 ] -L'^mcult. Obserred \ hour west of the meridian; the small star is light blue, and bears but an indifferent illumination j stars steady, and admirably defined. Passy ; July 16, 1825 ; Seven-feet Equatorial. 6th and 10th, or 11th magnitudes. Position = 84° 47' nf I 7 Obs. Distance^ 3". 43 1 j 5 Obs. Diff;=o".697}^^^^^^'^^^^"l^- The measures procured when the stars were 25 minutes west of the meridian; the small one is decidedly light blue ; not steady. and positions of 36 double and triple stars , &c. 373 No. XXVIII. R. A. iSJ^ 21' ; Decl. 58'' 42' N. 39 Draconis ;- 1. 7 ; H. and S. 269. continued. Passy ; July 20, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position = 84** 7' »/| 7 Obs. Distance rr 3 "-65 5 j 5 Obs. The small star is blue, and bears a tolerable illumination. Iffi^^-.s'sB}""""''^- DifF. = Diff. Passy ; July 21, 1825 ; Seven-feet Equatorial. 6th and 10th magnitudes. Position = 84° 58' nf 7 Obs. I DifF. = 3° 58' 1 Unsteady Distance = 3".503 5 Obs. | DifF. = 0^481 | ^"steaay. The small star, which is light blue, bears a very tolerable illumination. Measures of A C. Passy ; July 14, 1825 ; Seven-feet Equatorial. Position = 68° 42' 7./ 1 5 Obs. | DifF. = 1° 9' 1 , Distance = i' zS".69i \ 5 Obs. J DifF. = i".6s9J ^^^^ "^^^y* Passy ; July 16, 1825 ; Seven-feet Equatorial. 6th and 9th magnitudes. 5 Obs. I DifF. = o°45' | R.^^er iin<:feadv 5 Obs. 1 DifF. z= o".5Z9) ^^*^^^ unsteady. Position = 68° 35' nf Distances i' 29".30i Observed when 10 minutes west of the meridian; a part, (perhaps a sixth) of the object-glass not in use, from the interference of the observatory timbers. Passy ; July 20, 1825 ; Seven-feet Equatorial. 6th and 9th magnitudes. Position = 68° 32' nf Distance= i' 28".862 5 Obs. 5 Obs. Z:=l°dW-'^'y Perhaps one-fourth of the object-glass unemployed. Passy ; July 21, 1825 ; Seven-feet Equatorial. 6th and 9th magnitudes. Position = 68° 34' nf Distance = i' 28". 903 Obs. I DifF. = 1° 9' ) -, ^ . . Obs. iDifF. =:o".84ilV^n^""''^^^^y- 374 Mr. South's re-examination of the apparent distances No. XXVIII. R. A. 18^ 21"^ ; Decl. 58° 42' N. 39 Draconis ; I. 7 ; H. and S. 269. continued. Mean Result. (Position 84° 40' w/(28 Obs.); ^^ A ^' iDistance 3^593 (20 Obs.) ; j^P^^^ ^^^^•^5' . . ^ (Position 68° 36' nf (20 Obs.) ;) ^ , ^f ^•^•iDistancei'28".939(2oObsO;l^P^"^^ ^^^^'^^' ' These observations afford no corroboration of the change supposed to take place in this star, but rather militate against it : the difference of 1° 25' between their mean and that of the measures of 1823, lying the contrary way to that presumed. (H.) No. XXIX. R. A. 181* 31" ; Decl. 38° 37'N. « Lyrae ; V. 31 ; H. and S. 272. Double ; 1st and 15th magnitudes, Passy ; July 6, 1825 ; Seven-feet Equatorial. Position = 43° 56' */ 1 5 Obs. | DiflF. = 2° 45'. Excessively difficult. Observed with 157, on the meridian. Passy ; July 23, 1825 ; Seven-feet Equatorial. 1st and I5th magnitudes. Position = 44" 4-i' sf 7 Obs. I DifF. = 2° 52' ) „ . , ,,— ,^ * . " ^//o i r\u. \ T\'.a: ^// i, ,> Excessively difficult. Distance = 41 .873 5 Obs. ) Diff. = o .841 5 ^ Observed on the meridian with 157. Passy ; July 24, 1825 ; Seven-feet Equatorial. 1st and 15th magnitudes. Position = 42° 35' */ 1 7 Obs. I Diff. == 1° 48' \ Excesssively difficult. Distance = 41' .935 | S Obs. | DijF. = i .6833 •' Observed with 157 ; stars on the meridian, and very steady. Passy ; July 25, 1825 ; Seven feet Equatorial. 1st and 15 th magnitudes. Position = 44° 3' «/ 1 7 Obs. Distance = 4i".o77 \ 5 Obs. Diff! = ;° J^^} ^Excessively difficult. Observed on the meridian, with 157. and positions of s^ double and triple stars, ^c. si 5 No. XXIX. R. A. iS"^ 31" ; Decl. 38° 37' N. a Lyrae ; V. 31 ; H. and S. 272. continued, Passy ; July 26, 1825 ; Seven-feet Equatorial. 1st and 15 th magnitudes. Position = 43° zo' sf\ 2 Obs. j DifF. = i® 20'. Excessively difficult. On the meridian, and observed with 1 57 ; the night is become cloudy ; no more measures can be procured. Passy ; July 27, 1825 ; Seven-feet Equatorial. 1st and 15 th magnitudes. Position 42° 26'*/ 7 Obs. DifF. = i°35'jg . , ,.g. , Distance 4i".366 5 Obs. DifF. = o".36o5 Excessively dimcult. Stars tolerably steady, and observed on the meridian with 157. Mean Result. Position 43° 3o' sf{s6 Obs.); Distance 4i".563 (20 Obs.); Epoch 1825.56 There is a change of — i° 23' in the angle and -j- o".535 in the distance since 1822. The former is in the direction pointed out in the former paper, and agrees tolerably in quantity with that assigned. The difference of distance pro- bably arises from error of observation. (H.) No. XXX. R. A. 181' 38m . Decl. 390 27^ N. 5 Lyras ; II. 6 ; H. and S. 278. Double ; equal ; each 8th magnitude. Passy; July 12, 1825 ; Seven-feet Equatorial. 7 Obs. I DifF. = 1° o' \c .• r . 5 Obs. I Diff. = o".4o8 ] Satisfactory. Position = 69° 6' */or np Distance = 3".438 Stars very steady and well defined, and 20 minutes east of the meridian. Passy ; July 13, 1825 ; Seven-feet Equatorial. Equal; each 8| magnitude. Position = 69° o' sfor np I 7 Obs. 1 DifF. = 2° 8' ) „ , Distance = 3^299 | 5 Obs. | DifF. = o".i92 ] ^^^ S^od. Observed on the meridian; stars very steady. 376 Mr. South' s re-examination of the apparent distances No. XXX. R. A. i8»» sS'" ; Decl. 39° 27' N. 5 Lyrae ; II. 6 ; H. and S. 278. continued. Passy ; July 15, 1825 ; Seven-feet Equatorial. Equal ; each 8th magnitude. Position = 690 21' np oxsf\7 Obs. | Diff. = 2-2' \ „ satisfactory Distance = 3".3i8 | 5 Obs. j DifF. = o".384 j ^^^ satisfactory. Observed on the meridian ; stars very steady. Passy ; July 16, 1825 ; Seven-feet Equatorial. Equal; each 8 J magnitude. Position = 60° 17' jyp or n/f 7 Obs. DifF. = 2° 13' > f^. .^, Distance =3^306 ^ "^ | 5 Obs. DifF. = o".434 ^°' '''^'^^- Observed on the meridian. Mean Result. Position 69* 11' np or 5/(28 Obs.) ; Distance 3".340 (20 Obs.) ; Epoch 1825.53. These observations corroborate the motion ascribed to 5 Lyrse. The change of position in 3.11 years amounts to — 0° 45'. Calculating on the presumed angular motion — o**.325, it should have been — 1° o'. The difference is nearly insensible. No. XXXI. R. A. 19^ 39'^ ; Decl. 44" 42' N. ^ Cygni ; I. 94 ; H. and S. 304. Passy ; July 26, 1825 ; Seven-feet Equatorial. The night being unusually fine, the instrument was placed upon this star when on the meridian : it was examined by Mons'. Gambart (Director of the Royal Observatory at Mar- seilles) and also by myself, with 181, 327, 512 and 787. Both and positions of sQ double and triple stars y &c. 377 No. XXXI. R. A. 19^ 39™ ; Decl. 44° 42' N. ^ Cygni ; I. 94 ; H- ^^^^ '^- 3°4- continued. observers agree that it is as round and as sharply defined as possible ; neither of us can entertain the slightest suspicion of seeing it elongated in any direction ; with 787 it has the appearance of a planetary disc, and is a most beautiful object: it; is so extremely steady, that with this high power there is not any difficulty in keeping it bisected by the wire of the micrometer, when placed perpendicular to the diurnal motion. No. XXXII. R. A. ig"" 41" ; Decl. 11° 22' N. TT Aquil^e ; I. 92 ; H. and S. 306. Double ; 8th and 81 magnitudes. Passy ; August 1, 1S25 ; Seven-feet Equatorial. Position = 32° 58' */ 6 Obs. Distance = i".368 " ) 5 Obs. Diff. = t".\ls } Tolerably steady. Observed with 413, when on the meridian. " If the position 32° 58' sf be exact, there must be some monstrous error in that given to the Royal Society in the first memoir, where the position stands 45° 27' sf; the only mode to reconcile the differences is, to suppose that in one instance the micrometer has been erroneously read lo de- grees." Note made in the rough journal at the breakfast table on the morning of August 2, when reducing the observations. Passy; August 5, 1825 ; Seven-feet Equatorial. ^ 8th and 8? magnitudes. Position = 32° 45' sf; single observation. Observed when 2^ hours east of the meridian : of course this measure must not be considered as a standard one, but MDCCCXXVI. 2 c 378 Mr, South's re-examination of the apparent distances No. XXXII. R. A. 19^ 41" ; Decl. ii*» 22' N. ?r Aquilse ; I. 92 ; H. and S. 306. continued. I think it is very evident the erroneous result will be that given in the published memoir; supposing the v^rong 10th degree to have been taken, the mean angle as read off, instead of being — 44° 33' would be — 54° ss' = + 35° 2/, a difference from the angle here determined easily enough to be admitted, when the closeness of the stars is considered. Passy; August 9, 1825 ; Seven-feet Equatorial, 8th and 8J magnitudes. Position = 32° 35' sf \ 6 Obs. [ Diff. = 2° 17'. Rather difficult. Observed with 413 when 20 minutes west of the meridian ; stars very unsteady, so much so that measures of distance are impracticable. Set the position wire to — 45°, and it is so intolerably offensive to the eye that it never can have passed for a measure ; the stars stride across the wire. There can be no doubt therefore, that the micrometer was in the obser- vations of September 1823, read o^ incorrectly, Passy ; August 10, 1825 ; Seven-feet Equatorial. 8th and 8^ magnitudes. Position = 34° 22' sf\ 6 Obs. Diff. =: 2°2o' ) „ ^ , ..„. ,^ Distance =i".S27 "^ | 5 Obs. Diff. = C.^Go] Extremely difficult. Observed when on the meridian with 327, the highest power which I can use to night with advantage. Passy ; August 12, 1825 ; Seven-feet Equatorial. 8th and 8? magnitudes. Position = 33<> 4' «/ ] 6 Obs. | Diff. = 2° 5'. Extremely difficult. Observed on the meridian with 327, the highest power which the unsteadiness of the stars will allow me advantageously to employ. Observations of distance are impracticable. and positions of s6 double and triple stars ^ &c. si 9 No. XXXII. R. A. 19' 41"' ; Dec!. 1 1° 22' N. TT Aquilae ; I. 92 ; H. and S. 306. continued. Passy ; August 17, 1825 ; Seven-feet Equatorial. 8th and 8$ magnitudes. Position = 34° 25' sf\ 8 Obs. I Diff. = 2° 55' ) ,, ^. n ^ Distance = ilsil *^ | 5 Obs. | Diff. = o''.i92 J ^^"^ satisfactory. Observed with 413, when 15 minutes west of the meridian; stars remarkably steady. Passy; August 21, 1825; Seven-feet Equatorial. 8th and 8| magnitudes. Position = 330 10' sf\ 7 Obs. I Diff. = i<> 30' ) t, , , , ^ . Distance = i" 786 | 5 Obs. | Diff. = o".48i } Tolerably steady. Observed on the meridian with 413. Mean Result. Position 33** 27' sf (40 Obs.) ; Distance i*.549 (20 Obs.); Epoch 1825.61. These observations make it clear that a mistake of 10° (as supposed by Mr. South above) must have been committed in the reading off of the micrometer in 1823. This star must therefore be struck out of the list of Binary stars, as the pre- sent measures compared with that of 1783 present only a difference of o* 57'. This v^ill serve among other instances to show how necessary it is to repeat the measures of double stars on several nights. ( H. ) No. XXXIII. R. A. 20^ 15" ; Decl. 77° lo'N. J6 Cephei ; III. 70; H. andS. 321. Double ; si and loth magnitudes ; small, blue. Passy ; August 23, 1825 ; Seven-feet Equatorial. Position = 38° 34' */ 7 Obs. Diff. = 3° 3' 7 Tolerablv steady Distance = 8".350 5 Obs. Diff. = o".745 ] ^ o^eraDly steaay. Observed on the meridian. 380 Mr. South's re-examination of the apparent distances No, XXXIII. R. A. 20^ 15" ; Decl. 77° 10' N. X Cephei ; III. 70 ; H. and S. 321. continued. Passy ; August 31, 1825 ; Seven-feet Equatorial. 6th and 1 0th magnitudes. 7 Obs. I DifF. = 2° 54' ) tt * j Stars on the meridian when observed. Position = 37° 33' sf Distance =: 8".240 Passy ; September 5, 1825 ; Seven-feet Equatorial. 7 th and 1 1th magnitudes. Position r= 33° 56' sf\ 7 Obs. Distance =:7".5 33 | 5 Obs. Diff. = 1° 50' Diff. = o".36o Small star decidedly blue ; night hazy ; stars unsteady : observed on the meridian. F. = 1° 50' ) r\-ai 1* T\-a: /' /: i Difficult. Dm. =1 o .300 3 Position rr 36° 52' sf Distance = 7''.692 7 Obs. 5 Obs. mk^tU]^'^'"'^'' Passy ; September 6, 1825 ; Seven-feet Equatorial. Gth and 10th magnitudes. Position = 350 7' ,/ 1 7 Obs. DifF. ^ 4° 26' ) j^.g.. ,, Distance = 7 ".540 | 5 Obs. Diff. = o^eoi ] -^"^^cult. Night very hazy ; stars unsteady ; the small one is light blue. Observed on the meridian. Passy ; September 10, 1825 ; Seven-feet Equatorial. 6th and IGth magnitudes. Diff. = 3° 5' Diff. == o".72 Small star pale blue; night hazy; stars unsteady, and on the meridian. Mean Result. Position 36° 24' 5/(35 Obs.); Distance i'.S^ji (25 Obs.); Epoch 1825.67. This star has been examined with much perseverance, yet there prevails considerable discordance betw^een the measures at different epochs, and our judgement must be suspended with respect to its motion. (H.) and positions of 36 double and triple stars ^ ^c. 381 No. XXXIV. R. A. ^o^ 59"^ ; Decl. sT 5^' N. 61 Cygni ; IV. 18 ; H. and S. 329. Double ; 7th and 8th magnitudes. Passy ; September 2, 1825 ; Seven-feet EqtiafoH^l. Postion = 3° 1 8' n/ 1 7 Obs. Distance r= i5".49i | 5 Obs. Observed on the meridian with 787 ; stars very steady. Passy; September 5, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 2° 41' nf\ 7 Obs. I DifF. = 1° 1' | TTr,cf«^„ Distance = is'lssz \ \ Obs. | DifF. = o".72i \ Unsteady. Observed when on the meridian. Night very hazy. Passy ; September 6, 1825 ; Seven-feet Equatorial. 8th and 9th, and 9th and 10th magnitudes. ,,^ Position = 3^7' nf\ 7 Obs. I Diff. = 0° ^%' \^^^^^^ ^^^^^^^^ Distance =: 15 .201 [ 5 Obs. | Diif. r= o .456) Night extremely hazy, particularly during the observations of distance. Stars on the meridian, and tolerably steady. Passy ; September 9, 1825 ; Seven-feet Equatorial. 7th and 8th, 8th and 9tli magnitudes. Position = 30 8' n/l 7 Obs. 1 DifF. = o^ 30' ) ^olerablv steadv Distance= i5".69i | 5 Obs. | DifF. = o".769 j tolerably steady. Observed when 15 minutes east of the meridian. Night very hazy. Passy ; September 10, 1825 ; Seven-feet Equatorial. 7th and 8th magnitudes. Position = 2° 54' nf 7 Obs. I DifF. = 0° 42' ) c-nsfactorv Distance = I5".073 5 Obs. | Diff. = o".36o5 i>atistactory. Observed on the meridian. Night hazy, but the stars are very steady. Passy; September 20, 1825 ; Seven-feet Equatorial. 7th and 8th, and 8th and 9th magnitudes. Position = 3° 22' nf\ 7 Obs. I Diff. = 2° 33' \ Cantain Beaufort Distance = is".689 | 5 Obs. | Diff. = o".4o8 j ^-^Ptam Heaufort. Position = 3° 7' n/ I 7 Obs. I Diff. = o° 45' ) j. Distance = i5''.o99 | 5 Obs. | Diff. = o".i92 5 ^<»"th. Night very hazy. Stars unsteady, and not well defined. 382 Mr, South's re'examination of the apparent distances No. XXXIV. R. A. 20^^ 59™ ; Decl. sT 6^' N. 61 Cygni ; IV. 1 8 ;H. and S. 329. continued. Passy ; September 24, 1825 ; Seven-feet Equatorial. 6th and 7th magnitudes. Position =s i"* 50' nf I 7 Obs. DiflF. = o® 46' ") <, Distance = i5".689 | 5 Obs. | Diflr. = o" .697 ]^^^'^^' Position =: 3° 1 3' n/ 1 7 Obs. f DifF. = 2" 8' 7 ^ , . „ Distances is".208 | 5 Obs. | Diff.= i".o34 i ^^P*^^" Beaufort. Stars well defined aud very steady. Mean Result. -s = n. Position 3° 4' nf {63 Obs.) ; Distance 15".444 (45 Obs.) ; Epoch 1825.70. The result here given affords an extremely satisfactory verification of our former measures, and of the mean motion + 0^.730 assigned to this star. The interval of the epochs is 3.8 years, in which + 2° s' ought by computation to have been described, while by observation + 2° 1 5' have been de- scribed. The distances too differ only by o".oi9, a quantity perfectly insensible. ( H. ) No. XXXV. R. A. 22^ 8"» ; Decl. 36° 51' N. ^,^ 1 Lacertse ? H. and S. 341 • Double ; 8th and 10th magnitudes ; small, blue. Passy ; September 29, 1824 ; Seven-feet Equatorial. Position = 78; 33' sp I S Obs. I Diff. = 1° 59'} Very difficult. Distance = 15 .434 | 5 Obs. | Diff. =0 .481 3 ^ Near this star, about 22* 4' ± Right Ascension, and 36° 52' ± North Declina- tion, will be found a minute double star of the ist or 2nd class ; but it is not measurable with this instrument, although the night is particularly favourable. Passy; November 21, 1824; Seven-feet Equatorial. 7th and lOth magnitudes. Position = 75° 4' sp Distance = i5".8o9 ^gb^: I SI i^-Jse I Ex.ren.el, difficult. The small star is very obscure. and positions of s^ double and triple stars , &c. 3S3 '"^ No. XXXV. R. A. 22^ 8- ; Decl. 36° 51' N. 1 Lacert2e ? H. and S. 341. continued. Passy ; November 24, 1824 ; Seven-feet Equatorial. 9th and 12th magnitudes, og asoiiail) ^o wr Position = 77° 55' sp I 5 Obs. I DifF. = 1° 24' 9 ^ ^ , ,.^ ,^ Distance = i5".864 | 5 Obs. | Diff. = o'.84i \ Extremely difficult. Night unfavourable. Mean Result. Position 77° 11' sp (15 Obs.) ; Distance 15". 732 (15 Obs.); Epoch 1824.84. When this star was observed, I v^^as not aware that obser- vations of it had been already communicated to the Royal Society which give, Position 78° 43' sp ; Distance I5".6i9 ; Epoch 1823.72. No. XXXVl. R. A. 22*^ 20™ ; DecL 0° 5/ S. ^ Aquarii ; II. 7 ; H. and S. 346. Double ; 7th and 7^ magnitudes. Passy ; September 4, 1825 ; Seven-feet Equatorial. Position = 88° if sp \ 7 Obs. '; Diff. = 0° 34'. Unsteady. The night is become so bad, that observations of distance cannot be procured. Passy ; September 15, 1825 ; Seven-feet Equatorial. 7th and 71 magnitudes. Position = 880 3,' sp I 7 Obs. I Diff. = 0° 53' 1 ^.^i^rably steady. Distance = 4 .039 | 5 Obs. | Diff. = o''.793 J * ^^^^'^"^y aii;au;r. Observed on the meridian with 787. Passy ; September 24, 1825 ; Seven-feet Equatorial. 7th and 71 magnitudes. Position = Sf ii'nf I 7 Obs. Diff. = 0° 54' 7 o_,._„ Distance =4.157 | 5 Obs. Diff. = o".i68 j ^o^^"- Position = 88° 42' nf 7 Obs. I Diff. = 20 58' ) ^ . 5. . u>oj,„ Distances 3".993 5 Obs. | Diff. = o"48i 5 ^^P^^'" iJEAUFORx. , Observed with 181 ; stars very steady. $84f Mr. South's re-examination of the apparent distances^ &c. No. XXXVI. R. A. 22^ 20'» ; Decl. o« 57' S. f Aquarii ; II. 7 ; H. and S. 346. continued. Distance = 4".032 | 5 Obs. 1 DifF. = o".432) ^. , ^ (South. Distance = f.S^s \ 5 Obs. | DifF. =s o".336 5 ^"" 'O/ | Captain Beaufout. Measures of distance gotten without any difficulty ; both stars sharply definedj and as round as possible with 787. Passy ; October 8, 1825 ; Seven-feet Equatorial. 7tli and 7| magnitudes. Position = 870 52' nf\ 7 Obs. DifF. = 1° 31' ) g Distance = ^".^66 \ 5 Obs. DifF. = o".2645 ^o^th. Position = 90° 7' nf \ 7 Obs. j DifF. = i° 16'. Captain Beaufort. Night become so hazy that the stars are no longer visible j when seen they were unsteady and ill defined. Passy ; October 9, 1825 ; Seven-feet Equatorial. 8th and 9th magnitudes. Position = 88° 28' nf I 7 Obs. I DifF. = 0° 56' ) <, Distance = 3".8o9 | 5 Obs. | DifF. =o".36o j ^0^^°' Position = SqO 56' n/l 7 Obs. I DifF. = 1° 2' } ^ . ^ Distance = 3".8l8 | 5 Obs. | DifF. = o".84i } ^^P^^"^ Beaufort. Night very hazy ; stars unsteady, DifF. = 6° 29' J - . , _ DifF. = o".937} ^°"s- Gambey. Position = 89° 15' nf\ 14 Obs. Distance = 4".o97 | 10 Obs. Mean Result. Position 88° 56' nf (jo Obs.) ; Distance 4".oi4 (45 Obs.) ; Epoch 1825.73. These measures verify the direction of the motion ascribed to this star, the present angle differing from that of 1822.27 by — o°33'. By calculation it ought to be — i°33'. The discrepancy between these and the former measures of dis- tance is extraordinary. (H.) JAMES SOUTH. Pflssy; Rue Franklin, No. 19, Latitude 48° 51' 31" N. Opposite the Champ de Mars and Longitude 1 3". 36 (of time) west of the the Ecole Militaire. Royal Observatory of Paris. C 585 3 RE^EXAMINATION OF SEVEN DOUBLE STARS, MADE WHILST THE FORMER PART OF THIS COMMUNI- CATION WAS IN THE PRESS. No. I. R. A. 4^ 18» ; Decl. 53° 3i' N. 1 Camelopardali ; H. and S. 43- Double ; 8th and 9th magnitudes ; small, bluish. Sloane-street ; February 8, 1826 ; Seven-feet Equatorial. Position = 36° 59' np 8 Obs. I DifF. = 3° 40' 7 yerv hazv Distance = io".2iz 5 Obs. | DiflF. = o".769 | ^^^ ^^^y* Observed when if hours west of the meridian ; stars ill defined, and very unsteady. Sloane-street ; February 11, 1826 ; Seven-feet Equatorial. Sth and 10th magnitudes. 8 Obs. 5 Obs. Stars extremely unsteady, and at times very indistinct ; observed when one hour west of the meridian. Position = 37° 31' np 8 Obs. DiflF. = i*" 43' ) „ Distance = io".593 5 Obs. Diff. z= o".84i ) "*''^* Sloane-street; February 12, 1826; Seven-feet Equatorial 7th nnd 8th magnitudes. Position = 37° 0' np 8 Obs. 1 DifF. = 1° 22' \ Tolerablv steadv Distance = 1 o'.oss 5 Obs. ) Diflr. a= o".9 1 3 5 ^ °^^^^^^^ '^^^'^y* Observed on the meridian j night favourable. Mean Result. Position 37** 10' np (24 Obs.); Distance io".287 (15 Obs.); Epoch 1826.10. Observations made in Blackman-street gave, Position 36° 26* np; Distance io*.45o ; Epoch 1822.05: hence this star is liable to no material change either of position or distance. MDCCCXXVI. 3 d 386 Mr. South' s re-examination of seven double stars, made No. II. R. A. 4'' 21" ; Decl. 42° 39' N. 57 m Persei ; H. and S. 44. Double ; 8th and 8| magnitudes. Sloane-street ; February 6, 1826 ; Seven-feet Equatorial. Position z: 70° 23' *p 1 7 Obs. I DifF. = 0° 43' ) p, » Distance = i' 5o".269 | 7 Obs. DifF. = i".4i8> '-^o^^X- Stars only visible by glimpses, and when seen very unsteady. Sloane-street ; February 7, 1826 ; Seven-feet Equatorial. 8th and 8^ magnitudes. Position = 70° 2^ sp I 7 Obs. Distance=i' 51". 192 | 7 Obs. Diff =0° 76 \ ^^^ ^^^^^^ and unsteady. Observed when 40 minutes west of the meridian. Sloane-street ; February 12, 1826 ; Seven-feet Equatorial. , 8th and 8^ magnitudes. Position = 70° 41' sp\ 7 Obs. I DifF. = 0° 43' ) Satisfactorv Distance = 1' 5o".638 j 7. Obs. | Diff. = i".5i5 J i>atistactory. Observed when 70 minutes west of tj»e meridian; stars tolerably steady and well defined. Mean Result. Position 70° 29' sp (21 Obs.) ; Distance 1' 50^.700 (21 Obs.)-, Epoch 1826.10. Our former measures were. Position 71® '8^'' 5 />; Distance 1' 5o".i93 ; Epoch 1821.91; agreeing sufficiently with the present determinations ta render it probable that the star is liable to no very important change : it is true, the distance here given differs 5-tenths of a second from that arrived at by our joint observations, and that it lies in the right direction ; still future observations must decide whether the discordance between Sir W. Herschel's measure of distance and our own, = 13". 77'', have any other foundation than instrumental- error of the micrometer employed in 1 783.- whilst the former part of the communication was in the press, 387 No. III. R. A. 6^ 14™ ; Decl. 4° 41' N. 8 Monocerotis ; H. and S. 69. Double ; 7th and 8th magnitudes. Sloane-street ; February 7, 1826 ; Seven-feet Equatonal. Position = 63° 38' nf 5 Obs. Diff.=o° 24' 1 Unsteady. Distances: i4".332 5 Obs. J DifF. = i",63S > ' Observed when 40 minutes east of the meridian ; night unfavourable. Sloane-street ; February 8, 1826 ; Seven-feet Equatorial. 6th and 8th magnitudes. Position Distance = 13 .890 J 5 Obs. I Diff. = o".2645 ^ Stars 10 minutes west of the meridian when observed ; night hazy. Sloane-street ; February 12, 1826 ; Seven-feet EquatoriaL 7th and 8^ magnitudes. Position = 65' 52' nf I 7 Obs. 1 Diff. = 2° 4/ \ Very unsteady. Distance = 14 .013 | 5 Obs. j Diff. = o .360) -^ ' , Observed when on the meridian ; stars tolerably well defined. Sloane-street ; February 25, 1826 ; Seven-feet Equatorial. 6th and 9th magnitudes. Position « 65° 2'«/| 7 Obs. I Diff. = o; 45' } Unsteady. Distance = 14".352 | 5 Obs. | Diff. = o'.6oi ) ^ Observed on the meridian. Mean Result. Position 64° 47' w/(24 Obs.); Distance I4''.i47 (20 Obs.) ; Epoch 1826.13. Observations with the Five-feet Equatorial assigned to this double star, Position 64° 39' nf; Distance 14".379 ; Epoch 1823.04, rendering it probable that no important change of position or distance need be expected in this double star. S88 Mr. South's re-examination of seven double stars, made^>z No. IV. R. A. 6^ 22-" ; Decl. 17° 54' N. 20 Geminorum ; H. and S. 72. Double ; 8th and 8|- magnitudes. Sloane-street ; February 7, 1826 ; Seven-feet Equatorial. Position = 60° 33' sp 5 Obs. I DifF. = o° 47' ) Unsteady Distance = 2o".892 5 Obs. | DifF. = o".6oi 5 •^"^^^a^^y- Observed when half an hour east of the meridian ; stars neither steady, nor well defined. Sloane-street ; February 8, 1826 ; Seven-feet Equatorial. G\ and 7th magnitudes. Position =: 59** 56' * ;> I 5 Obs. Distance;:: 1 9".886 | 5 Obs. DifF. = o" 40' Diff. = 0.673 }"^^y* Observed when 1 8 minutes west of the meridian ; stars very unsteady. Sloane-street; February 11, 1826; Seven-feet Equatorial. 8th and 8 J magnitudes. Position =: 61° 17' sp \ 5 Obs. { DifF. = 3° 15'. Extremely unsteady. The night is become so unfavourable, that I cannot procure any measures of distance. Sloane-street ; February 12, 1826 ; Seven-feet Equatorial. 8th and 8J magnitudes. Position = 60° 48' -J i> I 5 Obs. I DifF. = 0° 54' ) Unsteadv Distance = i9".976 | 5 Obs. | DifF. = i".5is j Unsteady. Observed when 10 minutes west of the meridian; stars tolerably well defined. Mean Result. Position 60° 38' sp (20 Obs.); Distance 20^251 ( 15 Obs.) ; Epoch 1826.09. Our former measures of this star gave, Position 61° s' sp; Distance 19".454; Epoch 1822.04; the former according sufficiently with the present determination ; the latter differ- ing more than might be expected, viz. nearly 8-tenths of a second: whether this arise from a real motion of one of the stars, or from erroneous observation, remains to be ascertained. whilst the former part of the communication was in the press. 389 No. V. R. A. 7^ 9" ; Decl. so"" 27' N. 20 Lyncis ; H. and S. 79. Double ; 8th and 8;^^ magnitudes. Sloane-street ; February 7, 1S26 ; Seven-feet Equatorial. Position = 16® 37' sp I 5 Obs. J Diff. = 0° 47' \ „ Distance = I4".722 j 5 Obs. | DifF. = V'.zoz ] ^' The stars on the meridian at the time of observation ; they are pale, ill defined, and unsteady. Sloane-street ; Febrnary 8, 1826 ; Seven-feet Equatorial. 8th and 85 magnitudes. PoMtion r: i6° 18' «j) 5 Obs. I DifF. =s o*> 56' Distance = I4".943 5 Obs. | Diff. = o".432 \ ^*^^- Observed on the meridian ; stars ill defined and unsteady. Sloane-street ; February 12, 1826 ; Seven-feet Equatorial. Equal ; each 8| magnitude. Position = 17° 32' sp ovnf 8 Obs. I Diff. = 1° 56' 7 ^t . j Distance = i5".532 5 Obs. | Diff. = o".384 j Unsteady. Stars tolerably well defined, and 1 5 minutes west of the meridian when observed. Mean Result. Position 16° 56' sp (18 Obs.) ; Distance iPy".o66[\s Obs.); Epoch 1826.10. By observations made in Blackman-street the position of this double star was 17° ^1' sp; Distance is". 966 (errone- ously printed i6".988); Epoch 1823.33; the former differ- ing very little, but the latter more than might be expected from the present determinations ; what is the cause of the discrepancy future observations must decide. S90 Mr. South's re-examination of seven double stars, made No. VI. R. A. 7^ 31°" ; Decl. 5° 43' N. 31 (Bode) Canis Minoris ; H. andS. 8s, Double ; equal ; each of the 9th magnitude. Sloane-street ; February 12, 1826 ; Seven-feet Equatorial. - Position r= 42° 25' sfov np j 7 Obs. I DifF. =: 5° 28' ) t^. ^ , j.^ ,^ Distance = i ".462 | 5 Obs. | DifF. - o".096 \ Extremely difficult. Observed with 413, when on the meridian; stars very unsteady, but at times well defined. Sloane-street ; March 15, 1826 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 39° 32' sf Distance = i".637 7 Obs. 5 Obs. DifF. = 2*' 42' ) T^.fl. ,^ DifF. = o\l88 \ ^'^^^^^' Twenty minutes west of the meridian, when observed with 327; stars tolerably steady, but faint ; the measures I consider good. Sloane-street; March 17, 1826; Seven-feet Equatorial. 9th and 9| magnitudes. Position :r: Distance = 39° 59' 'f I H Obs. I Diff. = 3^ 3' { Difficult. =: I .200 ! 10 Obs. j DifF. =:o .192) Observed with 327, when 40 minutes west of the meridian ; stars tolerably steady, and extremely well defined ; observations deemed satisfactory. Sloane-street ; March 18, 1826 ; Seven-feet Equatorial. 9th and 9| magnitudes. Position = 42° o' «/ j 4 Obs. | Diff. = 1° 30'. Difficult. The night is become so cloudy, no more observations can be procured. Mean Result, Position 40" 40' 5/(32 Obs.); Distance 1^.405 (20 Obs.); Epoch 1826.18. Our former observations gave sT 8' sf for the position of this double star. Epoch 1823. is ; offering a difference of more than s\ degrees with the present determination ; but the observations are attended with so much difficulty, that no positive conclusion can be formed relative to the rest or motion of this star : the first memoir contained no observa- tions of distance. whilst the former part of the communication was in the press. 391 No. VII. R. A. 9M9" ; Decl. 9° 60' N. cJ^ Leonis ; I. 26 ; S. 600. Double ; 6th and 9th magnitudes ; small, pale blue. Sloane-street ; February 12, 1826 ; Seven-feet Equatorial. Position = 64° 14' sf \ 6 Obs. ] Diff. = 4° 42'. Excessively difficult. The small star only visible by glimpses ; observations made on the meridian,, with 787 ; the extreme unsteadiness of the stars renders it impossible to procure any measures of distance, and those of position must be received with caution. The unfavourableness of the weather has not allowed me to procure other measures of this difficult star. Sloane-street? March 18, 1826. The position April 4, 1783, was measured with a 20-feet reflector, 12 inches aperture, and found to be 20° 54' sf. The change is very great, no less than 43° 20' in 42.8 years, or almost precisely a degree per annum. There can be little doubt, therefore, that this very curious double star is entitled to a place among the revolving stars or Binary systems. The uncertainty of the present observations, arising from the difficulty of the star, and the unfavourable weather, might render us cautious in admitting this conclusion ; but a series of well-agreeing measures by Mr. Struve, on four nights, from Feb. 25, to April 4, 1825, which give a mean result 63°.? sf sufficiently establish the fact. These interesting observations are contained in a letter from Mr. Struve, dated April 21, 1825. (H.) JAMES SOUTH. 132 Sloane-street, April 7th, 1826. CiD A Synoptical View of the Results afforded by the Observations detailed in the present, and preceding communications. 6 398 7 24 25 star's Name, &c. 51 Bode Androm. 27 Bode Ceti . . . . 1789; 214 35 Piscium 38 Piscium Observer and Number. S 381 H&S361 S 382 H&S..I H&S..2 b. m. O O O 2 O 5 O 6 O 8 45 23 N 4 4S 61 49 N 7 49N 7 51N O / 4 39 18 45 85 50 60 46 32 9 Quadrant. nf np sp Distance. . . . 5.009 . . . 9. COO .. 18.187 1. 11.168 . . . 4.967 Unchanged. Distance estimated. Unchanged. Unchanged. 9 26 Nova V. 85 Nova 5 1 Piscium Nova S....383 S....384 S....385 H&S..3 S....386 o 9 o 10 o 16 o 23 o 23 15 32N 37 20 N 31 31N 5 57 N 27 32 N 39 44 76 48 81 25 7 " 74 34 sp «/ 0, nf 12.100 45-744 . 5.636 25.866 42.281 Increase of Dist. =: 1 5" nearly. Changed in Position. 10 27 10 28 29 30 30 313 II 32 33 H. C. 478 It Androm , H. C. 307 « Cassiop , 142 Bode Androm. S....387 H&S..4 S....388 H&S..5 H&S..6 o 26 o 27 o 27 o 30 o 37 17 55N 32 43 N 29 1 N 55 33N 29 58 N 38 I 85 26 56 18 7 34 52 o sp, nf np np 12 34 12 34 35 V. 82 . . . , ») Cassiop. 78 Bode Cassiop. 65 Piscium Nova H. C. 249 164 Bode Androm. P.O. 251 26 Ceti yj Piscium H&S..7 H&S..8 S. Re-exam, S....389 H&S..9 H&S.io o 37 o 38 o 38 o 40 o 42 50 7N 56 51 N 50 27 N 26 43 N 67 51 N II 29 7 56 6 55 57 35 25 48 55 12 S....390 H&S.ii S....391 H&S.12 H&S.13 o 49 o 50 o 50 o 54 o 56 16 38 S 43 44N o 11 S o 24N 3 57N S7 7 78 57 26 27 H 39 7 20 «f nf nf np, sf sp sp sp np sp nf 42.510 35-95 » . 6.554 46.464 Unchanged. Unchanged in Angle ; Dist. perhaps incr. Unchanged : pale, ill defined stars. 47-136 . 8.789 - 9-9°4 . 2.569 . 5.960 • 3-151 Change 3° 41' in Pos. and — 3 ".706 in Dist, Binary, -f o°'5 ' 33 = niean ann. mot. Epoch 1825.78. A slow change probably in Angle. Binary ? — o°.i 17 per annum. .7.781 . 7.520 18.866 15.756 32.069 Unchanged. Unchanged. 36 13 H 37 ^5 74 -^ Piscium ni.73 (7* Piscium . . . Polaris 160 Bode Ceti H&S.14 S....392 S....393 H&S.15 S....394 o 56 o 56 o 56 o 58 o 58 20 30 N 6 25S 31 13N 88 22 N 2 41 S ^5 4' 42 j6 16 IV. 120 ^Piscium 37 Ceti iy'77 119 Bode Cassiop. S....395 H&S.16 H&S.17 S....396 S....397 31 7N 6 37N 8 45 S 8 33S 63 43 N 71 2 82 42 21 8 61 11 57 19 21 43 26 33 62 27 67 34 82 53 np sp np sp nf np np np 30-340 12.893 90 ±: 18.701 .4.144 Position unchanged. Pos. changed 8° 6' ; Dist. diminished 2". Change of 6° in Pos. ; but identity of the star questionable. Unchanged. 19-373 24648 50.780 19.891 50.357 Unchanged. Unchanged. Pos. unchanged ; Dist. much increased. Pos. changed 4° ; Dist. unchanged. \ Cassiop. . . Nova 100 Piscium %' Ceti 42 17 43 17 18 IH.C. 247... H&S.18 S....398 H&S.19 S....399 S . . . . 400 13 19 25 33 34 67 7 II 12 7 iiN 3N 38N 12S 59S II 8 9 o 75 19 17 35 4 2 */ «/ nf sp 33-347 9.752 16.018 .4-»93 36.645 Unchanged. Unchanged. MDCCCXXVI. 11 A synoptical view of the results afforded by the observations Vol. for 1826 1826 1824 1824 i8z6 1824 18 19 44 45 20 46 star's Name, &c. 1826 1824 1824 1824 1824 1826 1826 1824 1826 1826 1826 1824 1824 1824 1826 1826 1824 1824 1826 1826 1826 1826 1826 1824 1824 1826 1826 1826 1826 20 46 47 47 49 21 22 50 23 23 24 52 53 54 24 25 304 Bode Piscium . 241 Bode Androm. y Arietis i and 2 . . I and 3 . . Nova 47 Cassiop IV. 104 X Arietis 292 Bode Ceti » Piscium . . . . y Androm. . . . . 1789; 223 , 14 Arietis 59 Androm H. C. 393 A and B. A andC. III. 68 J Trianguli 66 Ceti H. C. 124 . X Persei . . . H. C. 140 . observer and Number. S. . . .401 S. . . .402 H&S.20 H&S.2I S....403 H&S.22 S 404 H&S.23 H&S.24 H&S.25 H&S.26 S....405 S 406 H&S.27 S....407 .408 H&S.28 H&S.29 H&S.30 S. . . .409 S. . . .410 h. ra. I 40 I I 42 44 45 47 » 47 I 48 I 51 I 53 I 53 » 53 I 59 2 2 2 3 2 4 2 5 2 7 21 23N 36 26 N 18 25 N 27 56 N 76 25 N 40 30 N 22 43 N .23 48 S I S3N 41 28 N 78 50 N 25 5N 38 uN I 18 S 19 28 N 29 27 N 3 17 S 29 34N 56 41 N 59 27 N Position. o / 82 26 71 42 88 41 4 46 75 52 77 41 Quadrant. Distance. 22 35 44 19 36 30 65 33 25 14 4 12 7 58 56 5 19 31 12 48 58 49 12 2 43 55 22 50 46 30 20 56 np np nf sp np,sf sp sp,nf np • 3-378 .4.258 . 9.109 48.764 • 5-673 33-594 20.590 37.889 . 9.080 . 5.428 10.909 55-303 45.258 . 4.956 4.079 . 8.952 .3.881 16.173 . 6.067 4-533 11.100 Remarks. Pos. changed 5° ; Dist. unchanged. Probably unchanged. Unchanged. Unchanged. Unchanged. Much changed if the same star. Unchanged. Unchanged. Pos. changed 3°. Pos. unchanged. Pos. perhaps changed 3°. Dist. unaltered. Pos. changed 7° 39'. Distance unchanged. No measures given by Sir W. Herschel. 54 399 25 25 27 28 28 55 56 29 29 29 29 I o a ? Trianguli , . . 0 Ceti f Cassiop. A and C. AandB. 378 Bode Ceti . . . . H. C. 48 H&S.31 H&S362 S 411 S. . . .412 S....413 2 » 2 10 2 14 2 17 2 22 27 49 N 3 48 S 66 35 N 16 8 S o 19N 61 4 16 52 22 24 53 23 sp np sp H-347 • 7-909 11.704 14-332 Changed in Pos. } As III. 4, doubtful if changed : of it as > close double, 1 have no satisfactory mea- Remarkably unchanged. [sures. Nova 30 Arietis 33 Arietis ....... iVova ; A and B . AandC, IV. 64; A andB. A and C S....414 H&S.32 H&S.33 S....415 22 26 30 31 S 416 2 31 17 37N 23 52N 26 17N 18 5N 39 31 N 89 II 2 26 88 20 28 48 31 29 60 30 53 53 np nf sp sp sp . 8.446 38.445 29.185 . 2.875 6.256 22.883 26.042 Dist. increased. Pos. unchanged. No sensible change of Pos. or Dist. in AB. 1826 1826 1824 1824 1824 1824 1826 1826 1826 1826 1826 1824 1826 1826 1826 1826 ■I 826 1826 1824 1826 1826 30 31 57 57 59 61 371 H. C. Nova Persei i and 2 1 and 3 ■TT Arietis 41 Arietis S....417 S 418 H&S.34 H&S.35 H&S.36 32 34 38 39 39 55 45 N 28 41 N 55 8N i6 42N 26 31 N 5 50 24 17 29 53 24 48 32 29 43 24 np np np np */ sp ..16.538 . . . 2.903 •- 28.959 3 57-175 . . . 3.076 2 7-557 Pos. variable -f 0^.25 per annum. Unchanged in Distance. 32 33 33 34 34 85 Bode Persei. ... 20 Persei H.C. 121 P. II. 220 41 Bode Ap. Chem, S.. S.. s.. s.. s.. .419 .420 .421 .422 -423 2 40 2 42 2 46 2 48 2 49 52 15 N 37 36N 43 47 N 51 38N 25 42 S 21 1 33 50 26 46 4 40 50 52 np sp np nf sp ' J-321 13.886 28.411 12.960 »7-754 Unchanged since 1804. Probably unchanged. 61 35 36 36 37 499 Bode Ceti II. 76 Nova ni.77 Steuve, 94. . . H&S.37 S. . . .424 s... s... s... 38 38 401 39 39 Struve, 93 . . . H.C. 31 7 Tauri H.C. 121 in. 45 S.. s., H&S S., S., 425 426 427 2 59 3 10 3 12 3 18 3 21 428 429 363 430 431 21 23 24 26 28 6 46N 19 8N 29 11 N 19 52N 27 6N 73 25 18 56 12 18 73 7 37 7 ■f sp sf, np */ sp 21.283 .7.501 10.345 • 7-798 43.575 Pos. slightly changed; Dist. increased i".7. Unchanged. 26 57 N 22 45 N 23 51 N 44 12N o 3N o 24 55 26 33 54 4 39 44 42 np nf,sp nf sp 11.674 11.640 21.055 41.511 . 5.812 Distance only estimated. Probably unchanged. detailed in the present ^ and preceding communications. ui Vol. for Star's Name, &c. 1826 1826 1826 1826 1826 40 42 42 1826 1826 1826 1826 1826 1826 1826 1826 1826 1824 1824 1824 1826 1826 1826 1826 43 43 43 44 45 46 47 48 48 62 (>?, 63 49 50 SO SI 11. 52 Nova; or 145 H.C. 122., H.C. 137., H.C. 371., 23 Struve, 105. Alcyone A and B B and C B and D 30 Tauri 43 Persei ^ Persei A and B A and C AandD 32 Eridani . 6 Persei i and 2 I and 3 P. III. 213 Nova A and B . ...AandC. Nova Observfer and Number. 432 433 434 43S 436 437 438 439 440 441 H&S.38 H&S.39 442 443 444 3 29 3 30 3 32 3 35 3 35 3 36 3 37 3 38 3 43 3 43 45 45 50 57 3 58 DecU 33 32N 28 iiN 37 48 N 40 55 N 56 31 N 23 27 N 23 32N ID 35 N 50 loN 31 20N 3 30S 39 29 S 22 41 N 13 54N 22 38 N 13 44 65 3 I 33 44 »8 16 2 29 43 18 42 74 8 33 54 31 H 59 Z9 65 2 71 14 85 27 79 I 79 38 54 o 37 41 23 S3 31 II 84 8 Qnadrant. sf, tip sp ¥ */ np np np nf nf sp sp sp np nf ^f */ ^f np • 3450 . 7.326 28.428 . 9.867 57.706 34.566 56 607 25.640 14.686 . 9.867 16.934 13.296 24-379 59.071 . 8.681 . 8.587 . 7.208 44.212 i.969 . 6.301 Remark!. Doubtful if changed or not. aaoLx Sir W. H*s observations veiy dubious. A C changed in t^os. by proper motion. Sensibly changed. . . Pos. unchanged ; Dist. increased sensiwy. 1824 1826 1826 1826 1824 1824 401 52 52 53 64 65 fx, Persei Struve, 117; A and B A and C 40 Eridani Tauri X, Tauri H&S364 S....445' S 446 H & S . 40 H&S.41 4 2 4 7 4 7 4 9 4 12 47 57 N 49 50 N 7 sVs 26 54 N 25 II N 1824 1826 1824 1826 1826 1826 66 54 ^7 385 54 55 62 Tauri . IV. 72... I Camelop. H.C. 136. IV. 75... H&S.42 S....447 H&S.43 S. Re-exam, S 448 S 449 4 13 4 13 4 18 4 18 4 18 1826 1824 1826 1826 1824 1824 56 67 386 56 402 68 145.24; or Nova. 57 m. Persei Nova III. 65 ... . 88 6?. Tauri 1826 1826 1826 1826 1826 1826 57 58 58 59 59 59 Aldebaran .... III. 100 H.C. 204 T Tauri II. 81 A and B ... A and C S....450 H&S.44 S. Re-exam, S....451 H&S365 H&S.45 4 19 4 21 4 23 4 24 4 26 452 453 454 455 456 4 26 4 27 4 28 4 31 4 32 1824 1826 1826 1824 1826 1824 1826 1826 1826 1826 69 60 61 70 61 55 Eridani. . H.C. 251... H.C. 42.... u Aurigae . . . 10 Camelop. H&S.46 S....457 S....458 H&S.47 S....459 35 44 44 47 47 71 62 63 63 64 62 Eridani. 1.68 Struve, 146 H. C. 465 . . . Struve, 149. H&S.48 S . . . . 460 S 461 S. . . .462 S....463 448 4 49 4 50 4 5' 4 52 23 52N 33 53 N 53 31 N 29 57 N 9 41N 39 35 N 42 39 N 47 3N 40 43 N 9 47N 16 10 26 22 8N ss 35 N 36N 35 N 9 9S I 34S 7 6N 37 36 N 60 II N 5 28 S I 23 N 26 25 N 3 22 N II 7 N 38 18 56 33 10 7 17 58 29 33 66 4 sp np ip */ sp nf 31-559 15.220 28.720 24.726 56.841 Unclianged. Unchanged. 19 37 29 49 36 26 37 10 55 43 67 30 7tp nf np np nf 25 2 71 8 70 29 74 18 59 o 28 59 53 49 II 22 60 53 58 28 56 24 6 o 48 20 83 41 73 8 82 I 62 18 15 16 83 49 68 36 10 26 60 25 sf sp sp sp nf np nf sp sp, nf sp np sp 29.052 19.865 10.450 10.287 15.254 22.900+ Unchanged. Pds. unchanged; DiSt; ihcfeased 3". Epoch 1 8 i6. 10. Pos. changed 5° 34' ; Dist. unchanged. . 9.578 50-193 50.700 0.454 12.468 9455 Distance increased -f i3''.7. Epoch 1826.10. Distance unchanged. np, sf up sp np sp nf sfnp sp nf 3o.ooo± 13-634 • 3-9>9 2.817 • 6-455 44.412 Unchanged. Pos. changed 5° ; Dist. increased i".7. Distance unchanged. 10.510 41.490 »6.933 . 7.892 19.859 Unchanged Unchanged. No measures given by Sir W. Herschel. 5.865 . 2.565 18.561 21.808 33.604 Pos. unchanged. Pos. changed 1 1° : probably a Binary sys- tem. Ann. mot. =: — 0*^.269. A synoptical view of the results afforded by the observations 64 65 65 66 72 73 315 67 73 74 67 68 68 75 69 70 H. C. 562 11.48 0 Orionis Aurigae A and B . AandC. H.C. 467 star's Name, &c. 62 Bode Camel P. IV. 278 105 Tauri Nova 26 Bode Orion, i & 2 I &3 IV. 43 H. C. 203 Capella 14 Aurigae 145.21 or Nova? Observer and Number. S 464 S....465 S....466 S 467 H&S.49 H&S.50 S. Re-exam. S 468 H&S.51 H&S.52 S . . . . 469 S....470 S....471 H&S.53 S....472 S....473 R. A. 53 53 57 59 49 79 oN I 20 N 21 27N 31 51N 14 isN 8 53 S 13 47 N 45 48 N 32 28 N 2 38N 17 40S 33 9N 8 25S 39 58N 15 26 S 76 23 41 42 19 3 15 40 34 36 10 6 8 42 72 37 78 2 45 37 28 I 7 38 17 37 69 19 55 24 8 30 34 I Quadrant Distance. np nf sp «/ np nf nf nf sf np sp nf np sp sp nf nf np 37.012 H435 49.990 . 4.571 38.827 21.763 21.916 27.183 34.206 14.610 . 7.054 Position hardly changed. Epoch 1825.06. Pos. changed 8° : Dist. unchanged. 48.304 . 2.822 . 8.878 1 42.143 3 13-941 . . 20.844 Remarks. Probably unchanged. Probably unchanged. Pos. unchanged : Dist. scarcely changed. "1 Sir W. H. gives no measures of this J star. 71 72 76 72 H.C.313 82 Bode Orion. H. C. 562 23 Orionis IV, 101 S....474 S....475 S....476 H&S.54 S....477 lo 56 S 8 13S 18 43 S 3 21 N 34 43 N 2 49 86 46 72 4» 62 40 76 14 np nf, sp nf np 10.939 35-678 39713 33-043 31.96+ Pos. unchanged ; Distance differs 6'. Unchanged. Position unchanged; Distances not com- parable. 73 73 74 74 76 77 1 1 1 Tauri Nova A and B . ...AandC. 52 1-53 H.C. 563 .478 •479 .480 .481 .482 17 13N I 39 N 45 N 46 N 28 S I 17 51 21 54 45 50 48 40 29 75 54 np sp nf np nf sp 77 77 78 78 78 Nova .... 118 Tauri Nova . . . . , IV. 110.. 32 Orionis S....483 H&S.55 S 484 S....485 H&S.56 5 5 5 5 5 21 38N oN 21N 24 N 48 N 30 S3 75 59 80 I 81 52 66 49 nf sp sf np sp ^■763 46.630 38.162 . 2.982 3-393 11.392 No material change. Position unchanged. Position unchanged. 27.602 . . 5.666 • 58.955 . 15.446 < 1.300 Unchanged. Position changed 6° 58'. Binary? mean motion — o^ .414. 78 316 80 near 33 Orion. ni 93 81 82 33 Orionis i and 2. I and 3 . i" Orionis Nova H&S.57 H&S.58 S. Re-exam. H&S.59 H&S.60 H&S.61 5 21 5 22 5 22 5 23 5 23 3 II N 16 55 N 3 9N 27 S 39N 62 41 52 4 51 18 63 21 55 54 89 57 83 9 sf nf np nf np 82 79 80 81 83 84 85 X Orionis 9 Orionis A and B . . AandC. AandD.. AandE.. I. 70 Nova A of S. 486 ; and A of S. 488 Nova H&S.62 S 486 487 488 489 5 25 5 26 5 26 5 26 5 26 9 48N 5 32S 21 53N 5 34S 6 7S 49 H 40 48 29 56 7S 3 58 28 21 39 1 46 43 36 49 u nf np nf np nf sp sp 24-731 - 9-79^ 10.861 . 2.025 19-734 54-875 8.912 Pos. unchanged. Epoch 1824.99. Unchanged. Unchanged. - 5-574 13-453 13.582 16.685 58.114 . 2.970 52.418 14.866 37.116 Unchanged. Pos. changed 14^.45 ; probably is Binary, detailed in the present , and preceding communications. Vol. for 1826 1826 1826 1824 1826 1^26 1826 1826 1824 1826 1826 1826 1^26 1826 1826 86 86 87 88 83 84 85 86 87 89 89 90 90 87 star's Name, &c. Nova I Ononis; A andB. AandC 26 Aurig* , cr Orionis; A and B . A and C . A andD. AandG. AandH. D andE. DandF. Observer and Number. Nova 9« 92 92 93 94 94 Nova H.C.260 H. C. 262 f Orionis; A and B A and C 187 BoBE Orion. . y Leporis . . 52 Orionis. H. C. 209 . Nova H.C.313,, .490 .491 S . . . . 492 H&S.63 H&S.64 H&S.65 H&s! 66 ■493 27 27 27 30 Decl. 5 34S 6 2S 30 22 N 2 43S Position. 5 30 S....494 S....495 S. . . .496 H&S. 67 S.. •497 S.. S.. S.. S.. s.. ..498 .•499 . .500 ..501 . .502 30 30 30 32 5 37 5 37 5 38 5 38 5 40 5 45 iSS o 15S 29 23 N IS 15N 2 3S 4 20 s 22 31 S 6 23 N 32 56N 8 28S 13 50N 55 s^ 51 58 13 26 6 41 28 S7 52 57 33 44 31 u 3 39 68 II 8 9 27 51 7? 12 4 60 49 3 82 50 3 7 79 25 69 19 I 6 87 54 39 10 Quadrant. sp sp nf nf np */ nf sp nf sp np nf np */ nf nf np sp,nf nf sp 17.680 . 12.085 . 49.784 . 12.327 . 12.912 . 42.765 30.805 10.13 1 45-375 . 11.136 8.255 18.317 Pos. changed 8° f. Pos. changed only 2*^ Pos. changed 4° 14'; Unchanged. Unchanged. Pos. unchanged. Very little changed. 7 Distances but . 7'. 3 little changed.. Dist. diminished I'.i-. 11.523. 26.501 . 9.867 . 2.625 7.667 33-844 . 1.654 59.460 21.558 45-524 Sir W. H. gives no measures of this star. Perfectly unaltered. 1826 95 1^24 1826 1826 1824 89 96 403 Nova ; A and B . . A and C . , & Aurigae H.C.319 Nova 4 1 Aurigiae S....503 H&S. 68 S....504 S....505 H&S 366 5 46 47 51 58 58 13 55N 37 "N 20 loS 14 2N 48 44N 44 9 67 17 82 16 12 22 84 9 83 16 np np sp, nf nf np ■ 39-946 21.764 5.051 • 5-253 . 24.662 . . 8.809 1826 1826 1826 1826 1^26 97 97 98 99 99 100 Nova , Nova , Struve, 216 , Nova H. C. 313; A andB. . . A andC. S.. S.. S.. S.. s.. . .506 ..507 ..508 ..509 ..510 5 59 6 o 6 4 6 4 14 oN 14 oN 2 32N 14 26 N 14 32N »9 33 47 35 22 39 71 57 6 43 64 43 sp */ sp sp nf .2.750 39.696 29.187 48-939 • 5-930 47-879 1826 1826 1826 1826 1826 100 lOI lOI 102 102 H.C. 315 H. C. 383 Nova . 5 Lyncis . Nova . . . . S.. S.. S.. S.. S.. ,511 .51Z 513 .514 •515 1826 103 1824 1826 1826 1826 1824 91 387 104 104 92 Nova ; A and B ...AandC. 8 Monocerot. . . Nova ...... H. G. 323 . . 15 Geminor. S....516 H&S. 69 S. Re exam S....517 S 518 H&S. 70 1826 1826 1824 1824 1824 1826 1826 1826 1824 1826 1826I I 105 105 93 93 93 316 3»7 3'7 94 388 106 229 Bode Aurig. . . . 11.89 1 1 Monocer. A and B B and C Comes . A and B B andC Comes S....519 S 520 H&S. 71 20 Geminor. H. C. 208 ... S. Re-exam. S. Re-exam, S. Re-exam. H&S. 72 S. Re-exam, S.. . .521 6 20 6 22 6 22 36 12 N 47 II N 21 14 N 58 30N 26 47 N 24 53 S 4 41N 16 32 S 16 8S 20 54N 52 35 N 5 24N 6 55 S 17 54 N 38 40 N 54 13 o 32 12 50 2 7 78 40 sp sp sp np np 11.654 . 8.238 58.9»3 35-445 18.999 Perfectly unchanged in Pos, 87 5 27 43 64 39 64 47 77 42 o 28 65 21 nf sp nf nf sp, nf nf sp 49 26 50 27 39 29 10 41 67 20 40 23 13 39 66 33 61 3 60 38 42 56 7tp nf irp f */ np sp sp sf 6.271 59-975 '4-379 H.147 23.830 15.600 32.693 Epoch 1826.13. Unchanged. . 5.223 6.964 6.862 3.243 . 7.990 . 3-278 10.957 19.454 20 251 .3.613 Perfectly unchanged. Unchanged. Unchanged. Epoch 1824.12. Epoch 1824.12. Epoch 1824.12. Epoch 1826.09. MDi:CCXXVI. A synoptical view of the results afforded by the observations star's Name, &c. 1 06 107 107 108 109 109 III. 75 142.2 or Nova? . . Struve,233; A and B AandC 145.60; or Nova? . " 84 Observer and Number. .522 •523 .524 .525 .526 h. m. 6 22 6 22 6 13 6 24 6 26 33N 22 N 15N 41 15 N 41 43 N Quadrant. 15 25 85 13 27 II 59 39 16 10 4 59 np «/ sp Distance. 10.774 16.882 53.280 46.511 25.585 . 1.664 Remarks. Pos. changed 9° ; probably a Binary system, 404 no III III 94 15 Bode Telesc. Nova Nova Nova; A and B . .. Aand C. V Canis Maj. . . . H&S367 S....527 S 528 S....529 H&S*73 26 27 28 28 29 41 40 N 23 19N 31 44N 12 23N 18 31's 43 o 67 48 64 4 72 56 80 45 10 8 sp 28.064 15.905 20.691 31-995 7-913 17.240 Changed in pos. ? in Dist. IIZ 95 95 318 318 113 "3 114 Struve, 238 12 Lyncis A and B. A andC. A andB. AandC. II. 72 H.C.267 c Geminor S....530 H&S.74 S. Re-exam S. Re-exam. S....531 S....532 S....533 97 114 116 116 56 Aurigae. Nova H.C.365.. 59 Aurigae. Nova . . . . , 6 29 6 30 6 33 6 33 6 33 59 37N 59 37 N 55 54N 7 49S 25 18N H&S.75 S....534 S....535 S....536 S....537 34 36 40 41 42 45 N 15S 30 N 5N 55S 46 48 68 39 36 50 64 21 35 21 10 57 79 49 3 42 72 52 53 13 65 47 48 19 II 51 np np nf sp . 4.063 • 2.593 . 9.849 • 2-529 .9.184 .4.519 12.607 51-577 Binary; — o°.5574 per ann. Pos. changed + o°.oo9 per ann. Epoch 1825.25. Epoch 1825.25. Pos. unchanged. Distance unaltered. nf sp np 55-386 18.252 12.538 21.601 30-305 Pos. unchanged. No material change. 117 117 98 118 119 120 Nova Struve, 250 3 8 Geminor 77* Canis Maj. A andB A and C AandD Nova ; A and B . . . . A and C S....538 S....539 H&S.76 S....540 S....541 6 42 6 43 6 44 6 47 6 50 23 55 S 46 47 N 13 24N 20 II S 22 24 S 86 44 60 36 84 24 57 S7 85 42 84 44 46 52 32 10 nf sp sp sp nf sf 27.806 . 8.229 . 5.528 45-033 52.957 8.360 24.097 Distance diminished. Pos. changed 6° 15' ; unchanged, Distance is perfectly 1 20 99 121 121 122 1.69 , t, Geminor. Nova . . . . , Nova . . . . , 1790; 387. S....542 H&S. 77 S....543 S....544 S....545 53 iN 20 50 N 22 25 S 22 35 N 73 23 N 66 54 85 27 1 25 49 51 8 32 sf np np sp.nf nf •3 3« 31 •9 31 ,891 ,032 •432 ,427 .085 Pos. changed 10° 30'; prob''. a Bin, system, Pos. slightly changed. 100 101 389 102 122 1 9 Lyncis A and B . AandC. 20 Lyncis 123 ^ Geminor Nova; A and B Aand C. Iir. 48 H&S.78 H&S.79 S. Re-exam H&S.80 S....546 S:.*.'.'547 7 9 7 10 7 15 55 37 N 50 27 N 22 18N 31 48N 20 48 N 43 5 86 45 17 21 16 56 74 35 89 22 20 47 50 44 sp sp sp sp np nf nf 14. 33- i5< »5 • 7- 19, 22 . 6 544 357 966 066 248 600 637 516 Scarcely changed. Epoch 1 8 26. 10. Probably unchanged. — 0°. 1 66 per ann. Binary ? 124 404 124 125 125 126 103 106 107 320 126 127 127 128 I Y.66 63 Geminor H.C. 314; A andB. .... AandC. H.C. 281 H.C. 261 S....548 H&S368 S....549 sWWYso S....55I 7 17 7 »7 7 20 7 20 7 21 22 30 N 21 49 N 14 13N iV * Vs 5 37N « Geminor. A and B A and C AandD A and B 1 45 . 1 9 ; or Nova ? . . 34 Bode Off. Typ.. Nova Nova H&S.81 S. Re-exam S....552 S....553 S....554 S....555 7 23 7 27 7 28 7 28 7 28 5 52 56 16 39 41 39 35 26 12 24 46 np np «/ sp ,35.619 Not materially changed. • 7- 51 40, .4, 999 627 041 559 32 17N 23 4S 14 6S 14 7S 14 4S 3 57 71 34 45 45 6 42 H 53 33 20 54 41 42 17 sp sp sp np np nf sp ■ 5 10, 17' .4 •9- • 7- 20, 34' 355 180 114 767 007 437 276 731 Binary ; mean mot. = — 0^.965 . Epoch 1825.26. No material change. li detailed in the present, and preceding communications. Vol. for 1826 1826 1824 1826 1826 1826 1824 1824 1826 1824 1826 1824 1824 1826 1824 1826 1824 129 129 107 130 130 131 star's Name, &c. P. VII. 159 Nova 31 Bode Can. Min. H. C. 275 Pollux; AandB . . A and C . . 1 09 «■ Geminor 1102 Argo Navis 132 V. 67 110 J2oi Bode Geminor. 132 INova 112 112 3 IH 1826 1824 1826 1826 1824 1826 1826 1826 1824 1826 1824 1826 133 "3 32J 133 323 325 134 9» 134 ^3S 136 117 328 118 136 Observer and Number. S....556 S....S57 H&S.82 S. Re-exam. S....5S8 S....559 H&S.83 H&S.84 S. . . .560 H&S.85 S....561 2 Bode Ursae Maj. } i4Canis Min. i and 2 1 and 3 Nova 1 1 Cancri 29 Monocer. I and 2 I and 3 Nova ^ Cancri A and B Aand C H. C. 263 1 9 Argo Navis . . . H.C.54 sf '*/ nf nf np nf nf 45.689 . 6.474 45.000 22.169 26.649 27-332 Unchanged. Pos. unchanged. Pos. unchanged. Pos. unchanged; Dist. — i".i9. Unchanged. 'Pos. unchanged. 3-5 '3 I 6.683 . . . 5.090 .. 38.128 75 20 8 24 27 30 II 17 80 15 60 23 26 I 65 30 54 6 76 15 32 26 60 50 82 36 np */ np np,sf np .np nf np «/ sp sp sp I . 3.766 24.581 58.608 44.199 51.840 10.829 Pos. very slightly changed. Scarcely altered. , . . 51.022 . .. 30.071 . . 21./J98 ..11.352 2 54,906 .. 16.843 ••'3H3 . . . 2.716 ...6.723 I 0.387 ... 3.632 14.205 40.865 59-331 7.869 33-500 20.304 Unchanged. Changed in Pos. and Dist. ? Slight change in Pos. Binary ; mean mot. -f 0° 30' per ann. Epoch 1825.30. Pos. changed 4°. 47 ; Dist. unaltered. Unchanged. Unchanged. Single measure. detailed in the present ^ and preceding communications. Vol. for 1826 1826 1826 1826 1826 62 63 Star's Name, &c. 64 64 65 P-X. 159 H.C. 331; A &B A &C Nova . P.X. 179. H. C. 227 Observer and Number. s.. s.. ,613 .614 s. s. s. ,6i5 .616 .617 10 39 10 39 10 39 10 43 lo 45 Deci. 14 41 s 14 20S 13 44 S 8 25N 1 17S Position. 78 57 72 26 68 44 88 44 3S 2» 87 47 Quadrant. sp tip np Distance. 31.651 . 7.262 17.861 26.078 12.510 35-223 Remarks. 1824 1826 1824 1826 1826 42 |54Leonis. Nova V. Ill ir. 78 . Nova . H&S 117 S 6i8 H&S 118 S. . . .619 S. . . .620 fo 46 10 47 10 49 10 57 10 58 25 43 N 20 9 S 59 50 N 8 oN 12 28S 8 19 54 16 51 ^6 74 1 73 19 sp • 7-023 19.101 35.010 . 8.637 32.698 Unchanged. Distance increased ? Unchanged. 1826 1826 1824 1826 1824 ^1 68 68 44 69 407 1790.386; AandB. A and C. , 1790-389 145.68 H.C. 61 145-104 S. . . .621 S. . . .622 H&S 119 S. . . .623 H&S 372 II o II 3 II 6 11 6 II 7 66 59 N 74 26 N 53 44 N 28 33 N 15 22 S 64 30 26 34 26 16 75 29 5 36 13 «/ np np np nf np 43431 23.201 12.479 13-144 .4.103 20 d: 1824 1824 1824 1826 1826 1826 45 45 46 331 69 70 1824 1824 1824 1826 1824 1826 1826 1824 1824 1826 1826 1824 1824 1824 1826 1826 1824 1824 1S24 1826 1826 1826 1824 1824 1824 1826 1824 1824 1824 1824 72 73 74 58 58 75 76 60 60 61 76 61 62 63 64 145.26 .... (pLeonis. . . I Ursae Maj. H. C. 498 H. C. 223 201 Bode Camelop. 83 Leonis T Leonis 57 Urs. Maj 145-70 Nova 1790; 381 88 Leonis 90 Leonis i and 2 . I and 3 . Nova H. C. 64 93 Leonis Nova I Virginis i and 2 I and 3 H.C. 385 IV.49 V. 60 65 Urs. Maj. i and 2 I and 3 2 Comae Beren 1790; 376 H.C. 232 Nova H.C. 354 207 Bode Camel. H.C. 152 Nova 2 Canum Ven Struve, 408 145.22 55 Bode Com. Ber. H&S 120 H&S 121 H&S 122 S. Re-exam. S. . . .624 S. . , .62s H&S 123 H&S 124 H&S 125 S....626 H&S 126 S. . . .627 S 628 H&S 127 H&S 128 .629 S. . . .630 H&S 129 H&S 130 H&S 131 .631 S. . . .632 H&S 132 H&S 133 H&S 134 S....633 S....634 S....635 H&S 135 H&S 136 H&S 137 S....636 H&S 138 H&S 139 H&S 140 H&S 141 II 17 II 18 II 19 II 19 II 21 II 21 II 21 II 23 II 25 II 28 II 30 II 38 II 38 II 39 II 39 II 43 II 44 ii 46 II 55 II 56 12 o 12 7 12 8 12 9 12 12 6 8S 2 40 S 32 33 N o 40S 15 16N 82 2N 4 oN 3 50N 40 20 N 42 21 N 16 26 S 60 40 N 15 22N 17 48 N 22 25N 27 57 N 21 13N 21 2N 9 15N 68 19 N 9 48N 16 26 N 47 29 N 22 28 N 52 55 N 15 48 S I 15S 54 28 N 82 43 N 6 15S 10 58N 41 40 N 81 6N 2 56S 28 5N 7 37 16 56 II 33 25 28 18 I 79 40 np sp sp sp nf 7.062 46.256 . 2.809 . 2.442 10.145 . 4.927 Much changed in Pos. and Dist. Binary. Epoch 1825.25. 43 61 79 « 79 45 o 21 60 45 O 22 50 14 61 8 36 41 5 34 4 o 86 15 65 3 3 25 53 19 89 4 61 44 75 57 55 26 24 17 31 15 4 26 7 3 7 4 46 19 13 16 18 9 24 37 10 29 50 15 72 58 23 42 np nf np»sf np sp sp np nf np nf np np sp nf nf sp np np sp nf np sp sp sp sp sp .. 21.876 . . 29.542 I 35.217 . . . 6.294 .. 13.040 28.959 13.040 14.670 • 4-452 0.753 44.374 ... 5.592 I 14.897 I 16.861 11.845 30.382 37-112 . 4.020 2.185 . 3.685 - 8.309 . 7.971 23-673 12.102 3-445 . 9.225 26.580 11-534 15-389 21.017 • 9-453 Pos. changed +6° 11'. Much increased in Dist. DifF. of Pos. = 4° 9'. Scarcely altered. No change. Pos. unchanged. Pos. changed 5° 14'. Dist. diff. 2''.9 Pos. changed — 5°. Unchanged. Scarcely altered. Very little, if at all changed. Unchanged. MDCCCXXVi. A synoptical view of the results afforded by the ohservatiom 165 333 166 77 167 77 167 [68 169 79 70 335 71 334 73 79 74 180 74 75 76 H. C. 230 .... . Nova IV. 58 I and z. .... I and 3. .... I and 4. 35 Comas Ber,. . H.C.73 180 [76 77 77 ,78 407 li li [80 [82 •83 181 ■83 li 182 182 ■ 84 185 ;85 [86 :8s ;86 408 [86 [86 [87 [87 [87 188 [88 star's Name, &c.- 17 Virginis 12 Com. Ber. Nova H. C. 385.., Nova ^Corvi H. C. 231 .., 145.118. . . . 24 Com. Ber. V. 129 Nova . . . . , 145-38 .... y Virginis III. 53 Nova . Nova II. 42 P. XII. 221 .. 12 Can. Ven. Struvk, 430. 212 Bode Camel. Nova Nova 9 Virgin, i and 2 ...... I and 3 Nova Nova 54 Virginis Nova P. XIII. 25 H. C. 506 . ^ Urs. Maj 426 BoDB Urs. Maj. V. 128 Nova iH.C.33s? Nova 8 1 Virginis . . 0 84 Virginis. Nova Nova Nova . . . . H. C. 335 Nova . . . . Nova . . . . fi Bootis . . Observer and Nuiiiber. H&S 142 S. Re-exam. H&S 143 S....637 H&S 144 S....638 H&S 145 H&S 146 H&S 147 H&S 148 S....639 S 64.0 H&S 149 S. Re-exam, H&S 150 S. Re-exam, H&S 151 S 641 H&S 152 S.. . .642 H&S 153 H&S 154 H&S 155 S....643 H&S 156 H&S 157 H&S 158 H&S 159 H&S 373 S 644 S....645 H&S 160 S....646 S....647 H&S 161 S 648 H&S 162 H&S 163 H&S 164 S 649 H&S 165 S. . . .650 H&S 166 S....651 H&S 167 H&S 374 S....652 S....6S3 S....6S4 H&S 168 S....655 S....656 H&S 169 R. A. b. m. 12 13 13 18 2 2 2 19 2 20 2 21 2 22 2 25 2 26 2 29 2 29 2 32 2 32 2 36 2 36 2 40 2 40 2 43 2 44 2 44 2 44 2 46 2 47 2 48 2 48 2 48 2 51 2 58 3 I 3 I 3 4 3 5 3 6 3 15 17 22 23 25 3 26 3 27 3 28 3 34 3 36 3 38 3 40 3 41 3 42 3 42 3 46 Decl. 6 19N 26 51 N 18 58S 45 50 N 26 54N 15 30 S 2 20N 75 46 N 19 22N 3 23S 4 22 S 12 1 S o 27S 2 54S 15 20N 4 48N 14 58N 20 9N 22 14N 16 oN 4S 54 S 29 N 18N iN 84 24 N 15 18N I 35N 4 34S 16 25 N I 43 S 7 5»S 19 oN 10 24S 3 38N 55 52N 60 53 N II 46S «2 33S 27 loN 25 35 S 6 57 S 4 27N 9 40S 19 18N 25 N S2N 35 N 12N 19N Position. 69 36 66 15 78 47 66 54 72 52 19 ^3 56 27 19 39 6j 10 2 7 15 22 5 50 29 26 31 27 13 24 6 78 56 35 75 38 53 50 67 49 59 23 4 o 38 18 79 53 60 19 73 43 43 2 15 »5 57 o 81 9 84 48 77 8 24 3 72 46 56 9 56 17 25 22 28 21 13 39 57 46 21 2 11 13 59 10 24 51 77 30 47 16 40 9 56 50 82 55 32 13 70 25 14 o 6i 50 29 27 Quadrant. np np sp .sp np np np sp nf sp np sp sp, nf np np np sp nf np np np sp nf nf, sp sf nf nf sp nf sp */ sp sp nf sp Distance. 20.937 19.910 5.950 »-635 11.079 24.436 24.005 49745 . 5.865 20.647 50-555 10.197 .6.881 . 6.077 • 3-794 . 3.263 16.766 33-359 10.109 54.421 9.666 31.644 29.494 • 7-995 23.509 6.758 29.170 19.764 .4.136 22.069 27.159 . 8,098 . 8.301 . 4.090 43 '29 . 6.774 28.970 44.847 28.465 14.455 1.495 47.720 45-524 . 9.613 10.350 . 4.020 .3.918 53.869 30.517 10.844 . 5.664 35-054 26.033 6.203 Pos. changed + 1 1^ Epoch 1825.30. Pos. unchanged. 15', arising from [proper motion, Unchanged. Unchanged. Epoch 1825.28. Binary; mean mot. — o°,667. Epoch 1825.32. Unchanged. Unchanged. Pos. changed ■\- 7° 55'. Unchanged. Pos. changed -f 7°5o'. Distance increased. Unchanged. Distance increased. Pos. changed — 6° 4'. Binary? mean mot. rr — o°.288. il detailed in the present, and preceding communications. Vol. for 1824 1826 1826 1824 1824 1826 1826 1826 1826 1824 189 88 i89 [90 [90 star's Name, &c. H. C. 162 Nova . . . . H.C. 335. T Virginis 145.82 ... observer and Number. H&S 170 S....6S7 S 658 H&S 171 H&S 172 R. A. h. m. '3 46 13 5» 13 52 13 54 Decl. o / 33 43 N 7 12S 26 41 N 2 26N 20 17N Position. 58 28 38 i6 28 52 19 57 71 43 Quadrant. np sp np Distance. .... 7.780 . . . . 2.699 5.016 . I 19.290 . .. 21.392 189 [90 [90 191 191 H.C.233. Nova . . . , Nova . . . , Nova . . . . 145.98... S....659 S 660 S....661 S....662 H&S 173 »3 56 14 o 14 I H 3 »4 5 17 12S 22 3N 2 30S 29 35 N 6 14N 79 *7 69 43 62 51 17 32 79 20 nf «/ sp 32.031 . 4.888 • 7-937 13.801 . 6.049 1824 1824 1824 1824 1824 3 [91 '93 [94 '95 [96 1824 1824 1824 1824 1824 [97 198 '99 200 201 1824 1824 1826 1826 1824 1824 1826 1824 1824 1824 1826 1824 202 204 336 191 208 208 33^ 213 216 409 192 215 1824 1826 1824 1826 1824 1824 1824 216 192 217 193 218 K Bootis . . . » Bootis P. XIV. 62 H.C. 334 . H. C. 470 . H&S 174 H&S 175 H&S 176 H&S 177 H&S 178 H H 7 10 »3 14 14 14 15 X Turdi Sol. H.C. 165 .. IT Bootis. . . , ^ Bootis . . . . II. 82 73 Hydrae { Bootis . . Nova . . a Librae I Bootis 39 Bootis H5-28 1 8 Librae Nova 346 Bode Bootis. 145-63 •.... Nova 45 37 33 Bode Urs. Min. 44 Bootis H&S 179 H&S 180 H&S 181 H&S 182 H&S 183 H&S 184 H&S 185 S, Re-exam, S....663 H&S 186 H&S 187 S. Re-exam. H&S 188 H&S 190 H&S 375 S....664 H&S 189 H&S191 S....665 H&S 192 S....666 H&S 193 14 15 14 22 H 32 »4 33 H 36 H 36 14 37 14 40 14 41 H 43 14 44 1448 14 49 H 53 H 55 H 55 H 55 14 56 14 56 14 58 52 52 6 9 12 39N 12N 56 S 16N 3N 3» 15 56 36 77 6 83 24 65 17 19 8S 29 6N 17 12N 14 31 N 8 27N 25 49 7 36 7 53 36 58 4 27 24 40 S 27 51 N 23 30 S '5 15S 19 51N 46 40 52 59 54 26 50 53 44 33 70 54 67 o 27 N 35 S 24 S 29 N 2N 54 33 N 17 13S 6 12N 75 36 N 48 21 N 44 55 o 9 54 8 84 2 68 S3 sp np sp np ^•136 38.047 . 5.880 . 7.185 1 o. 1 92 Pos. slightly changed. Very little changed. np sp 35.121 25.781 . 6.889 . 1.683 • 7.335 np np sp np np np . . . 9.995 ... 3.931 ••• 3.356 . . 56.696 3 50-853 . . . 8.696 . . . 7.776 73 »o I 51 j6 30 52 3 40 53 np nf sp -L np ^f np nf sp . 4.626 10.833 26.614 25.837 36.544 . . . 40.845 . . 25.270 . . 10.749 2 53.180 ...2.277 Unchanged. Unchanged in Position. Changed 8° 25' in Pos. Binary; mean mot. +o°.4378. Epoch 1825.34. Greatly changed in Pos. and Dist. Epoch 1825.37. Probably changed in Pos. ; our observa [tions rather dubiou Unchanged. 219 410 1826 1824 1826 193 220 194 H.C. 472 24 Librae 1 and 2. I and 3 , Nova 97 Bode Librae... Nova H&S 194 H&S 376 S....667 H&S 195 S 658 14 59 15 2 •5 3 15 4 ^S 4 55N 6S 60 50 21 39 4 55 S 17 45 S 39 38N 21 39 65 39 50 58 63 50 sp */ np sf np • 4-777 50.629 31.181 49037 10.740 1824 1824 1824 1826 1824 221 221 222 '95 222 V. 125... 14562 ... H. C. 289. Nova . . . . ^ Bootis . . H&S 196 H&S 197 H&S 198 S....669 H&S 199 »5 5 15 8 28 36 N 19 56N 39 22N 15 5N 34 oN 43 17 80 51 13 29 73 8 10 31 sp nf np nf nf 32.553 35.842 31239 . 6.057 45-333 1824 1826 1824 1S24 1824 1826 223 195 224 225 226 339 H.C. 470... 5 Serpentis. . « Coron. Bor. H.C. 288... 17 H&S 200 S. . . .670 H&S 201 H&S 202 H&S 203 S. Re-exam. 15 10 15 lO 15 16 15 18 15 18 II 7N 2 28N 30 57 N 8 41 S 37 59 N 84 20 50 57 64 3 44 39 63 42 ^3 32 nf nf */ np np 13.268 10.698 • 1-577 51.760 . 1.652 . 1.421 > I, 2 and 3 are precisely in a line. Slightly changed in Pos. Scarcely changed. Binary; mean mot. — 0**.578j. Epoch 1825.46. A synoptical view of the results afforded by the observations Vol. for 229 196 197 197 231 341 411 232 198 234 1824 1824 1824 1824 1824 1826 1824 1824 Star's Name, &c. HA Bootis . . . Nova Nova Nova S Serpentis . Struve, 489 178 Bode Librae. . . Nova H. C. 469 ^ Coron. Bor 236 145.32. 237 238 239 240 Observer and Number. H & S . 204 S 671 S 672 S 673 H&S.205 S. Re-exam. H&S. H&S. S H&S. H&S. 377 206 674 207 208 w' Urs. Min. II. 85 III. 103.. H.C. 343. 198 199 240 241 1824 1826 1826 243 343 345 346 199 Nova J A and B . . .. AandC... V. 126 II. 21 ; I and 2.. I and 3.. I Scorpii AandB. AandC. B andC. Coronae Bor. . . . H&S. 209 H&S. 210 H&S. 211 H&S. 212 H&S. 213 R. A. h. m. 15 18 15 18 15 22 15 23 15 26 15 27 IS 30 15 32 15 33 15 33 15 40 15 40 IS 47 15 48 IS 49 Decl. 38 IN 10 20 S 19 35 S 23 52 S 11 9N Position. Quadrant. 27 20 N 8 iiS 36 54N 10 33 S 37 iiN S 675 H&S. 214 H&S. 215 H&S. 216 S. Re-exam. S 676 IS 51 15 52 IS 54 15 54 IS 54 36 59 N 81 2N I 39S 3 5 6N 19 24S 22 16N 17 S4N 10 56 S 10 52S 33 52N 81 51 42 44 13 14 27 24 70 37 69 49 30 20 82 46 5 o 38 5 30 57 S3 43 6 43 55 »7 S3 4 52 10 np np,sf sp sp sp sp sp nf np 61 46 33 34 53 25 10 57 78 39 11 37 81 54 9 3 »7 30 35 6 np nf np np np Distance. I 48.539 •••9-573 .. 11.468 ...9.178 ... 3.053 ...3.268 .5.941 11.862 15.648 27.066 .7.168 sp sp sp */ np nf 31-517 31.102 . 6.882 10.665 19.890 Unchanged. Binary ; mean mot. — o°.']z6. Epochs 1825.46 and 1825.42. Changed + 5° 6' in Position. Changed — 9° 8' in Pos. and nearly 3" in Distance. . . . 5.086 I 1-533 • • 34.923 . . 10,601 4 41.533 . . . 6.769 ...1.358 . . . 6.961 I 19.196 Binary ? Mean mot. — o°.256. } Epoch 1825.50. Not the slightest alter- ation in the Pos. or Dist. of A. and B. Sir W. H's Pos. = 54° 27' sf Mr. H. sup- poses his micrometer was erroneously read off. 1824 1824 1824 1824 1824 1826 244 245 246 247 247 347 jS Scorpii . . H.C. 159. x Herculis. Scorpii. . . 49 Serpent. 1824 1826 1824 248 348 350 252 0- Coron. Bor. 1824 1824 1824 254 255 256 1824 1824 1826 1826 1824 1824 1824 1824 1824 1824 257 259 201 202 260 H&S. 217 H&S. 218 H&S. 219 H&S. 220 H&S. 221 S. Re-exam. ^Aand B A andC V Coron. Bor. 1 and 2 I and 3 20 o- Scorpii V.134 V. 124 H&S. 222 S. Re -exam, H&S. 223 H&S. 224 H & S.225 H&S. 226 y Herculis . . . g 5 Ophiuchi. II. 88 23 Herculis. . H &S.227 H&S. 228 s (>n S 678 H.C. 78. H&S. 229 IS 15 16 16 16 16 8 16 10 16 10 16 10 16 10 16 14 16 15 16 15 16 16 16 18 18S 49 N 32N 58 S iN 63 30 58 44 80 25 68 12 41 57 48 10 ^f np nf np np,sf np 34 20 N 29 36 N 25 9 S 19 36 S 19 40 s 19 35N 23 iS 14 15 N 32 45 N 37 27 N 18 27 12 29 0 39 65 33 35 9 1 II 64 58 69 29 26 14 87 30 48 23 69 38 j6 21 nf ff sf nf nf 7ip np nf sp nf np nf np 13.650 31.935 31.169 40.817 .4.215 .3.501 Unchanged. Distance diminished 8".7i 1. Unchanged. Binary; mean mot. + o°.5io. Epoch 1825.41. • 1-455 . 1.480 42.175 28.694 6.420 20.595 47.120 13.280 Binary; mean mot. -f 2.13, much lerated and Dist. diminished. Epochs 1825.44 and 1825.49 Epoch 1825.53. Unchanged in Distance. Slightly changed. acce- •38-325 . . 4.065 . . 6.770 . 36.844 . 10.155 No material change. Sir W. H's. Pos. zz 54° 6' sp ; it cannot be the same star. 261 261 262 263 263 III. 102 71 Bode Hercul. 11. 23 , H, C. 228 36 Hercul H&S. 230 H& S.23 1 H&S. 232 H&S. 233 H& S.234 16 21 16 21 16 23 16 23 16 32 iN 47 N 51N 42 N 33N 71 26 19 12 51 7 17 29 39 37 np nf . . . 14-833 ....3-236 . . . . 7.649 ...59.544 .1 8.839 Probably changed in Pos. detailed in tJw present, and preceding communications. Vol. for 1824 1826 1824 1824 1826 1824 1826 1824 1826 1824 Star's Name, &c. 265 20Z 264 1826 1826 1824 1824 1824 1826 267 267 203 268 203 412 17 Dracon Nova V. 127; I and 2... I and 3 . . . f Herculis Observer and Number. H.C. 369. Nova 1826 1824 206 1826 1824 1826 1824 1824 1826 1824 1826 1826 1824 207 269 269 271 352 43 Herculis. 46 Herculis. 19 Ophiuchi 208 272 1826 1826 1826 1824 1824 3 353 354 355 274 208 275 Nova ; A and B . . . A and C... A and D . . . Nova P. XVI. 236 H.C. 510 2 1 /* Draconis , H&S.236 S .679 H&S.235 R. A. H & S.237 S. Re-exam. H&S238 S 680 H&S 239 S 681 H&S 378 h. m. 16 32 16 32 16 34 Decl. 16 35 ^6 35 16 35 16 37 16 38 16 38 1824 1826 1824 1824 1826 276 364 277 210 210 277 Nova 36 Ophiuchi I and 2 I and 3 A and B.. A andC. B andC. « Herculis 38 Ophiuchi ^g 0 Ophiuchi. . . . S 682 16 S....683 H&S 240 H&S 241 H&S 242 S. Re-exam. 39 53 17 N 23 23 N 6 57N 31 56N Position. 24 oN 13 58N 8 55N 28 42N 2 24N 25 I 21 74 26 5 o 10 Qualrant. Distance. 21 27 65 36 39 9 73 51 10 ± S....684 H&S 243 S. Re- exam. H&S 244 S....685 H&S 245 30 18N 36 15 N 19 15S 47 36 N 54 43 N Herculis H&S 246 S. Re-exam, » Serp. Ophiuch | H&S 247 Nova 70 Herculis p Herculis . 211 iNova 211 Nova 2 1 2 Nova 278 279 280 1826 1826 1826 1824 1826 1824 1824 1824 >82+|3 1826 I 213 281 283 214 53 Ophiuchi v Draconis . . 254 Bode Oph. i 8c 2 1 and 3 2 and 3 III. 104. A and B.. . A and C . 61 Ophiuchi H. C. 348 Nova S 686 S....687 H&S 248 S....688 S....689 S — .690 H&S 249 H&S 250 17 H&S 30 37N 26 18 S 14 36N 26 25 s 24 5 S 59 42 50 27 76 15 69 30 42 44 6 3 61 39 61 2 np np np sp ...4.512 • • 17.034 • • 54307 I 30.275 Single. Single. 10' . 6.755 13.929 20.094 • 5-391 or 15" 89 10 42 41 19 5 41 32 16 1 17 41 29 33 60 50 85 47 nf sp np sp,nf sp,nf Remarks. Unchanged. 1825.57. No certainty in Pes. j but increased i [Distanc( 251 214 215 216 284 216 285 286 412 287 217 i^ Herculis. . . . 295 Bode Oph. Nova ■vj/ Draconis . , . Nova S .... 69 1 H&S 25 2 H&S 253 S. . . .692 25 3N 12 39S 28 57 N 24 41 N 37 19N 37 8N 39 25 N 35 5N 9 43N 55 19N 82 10 83 33 S9 13 85 31 33 26 37 53 sp,nf np sp np np */ np np .. 14.761 I 4.299 1 min. ± ...7.158 . . . 5.641 1 55.126 . . . 3.907 • • • 4-330 np ■ • 24.499 ..5.546 Distance . . 5.200 ; 15.252 t 13.689 ..5.286 •• 7.137 . 12.512 Binary; mean mot. — o°.5792. Epochs 1825.52 and 1825.47. 17 30 2 8N 17 32 17 36 17 36 17 38 S. . . .693 S . . . . 694 S 695 H&S 254 S....696 6y Ophiuchi H.C. 168 .. H5-40 95 Herculis. II. 90 , H&S 255 H&S 256 H&S 379 H&S257 S....697 ^7 39 '7 43 17 43 ^7 45 17 51 17 52 17 52 17 52 '7 54 '7 54 24 30 N 2 41 N 13 14S 31 14N 76 13 71 39 39 25 78 41 42 23 58 7 68 37 27 23 81 2 71 50 3 33 66 48 65 33 sp sp np, sf . . . 28.869 . . . 26.694 ..50.213 ..54.982 3 38.339 . . . 4.463 Inaccurate from erroneous micrometric Epochs 1824.86 and 1825.17. [readin Epoch 1825,27. Epoch 1825.53, Unchanged. Pos. unaltered ; Dist. increased 3", if tht Unchanged in Pos. [same star, Altered + 9° 42' in Pos. and— 5*.349 j Epoch 1825.50. [Dis Pos. changed 7° 32'; Dist. + i".494. 27 50 N 1 loN 25 19 N 72 14 N 6 51 S 2 57N 30 5N 22 58 S 21 36 N 26 33 N 29 H 32 6 54 30 75 14 77 45 53 4 */ 8 53 np 61 45 sp 8 8 nf 71 46 ^f np nf nf nf */ sp np sp sp */ nf np • - 33.348 1 29.272 . . 10.799 . . 41.662 1 2.242 51.213 1 8 . 090 54-310 17.214 28.267 20.520 15.869 . 5.029 Unchanged in Pos. Unchanged in Pos. 29.297 22.681 . 6.768 31777 . 8.396 Change in Pos. -f 2^46' and + 2".88i in ' [Dist. Unchanged. Probably unchanged. 55.228 20.181 10.952 . 6.623 • • 7.503 Perhaps slight change in Pos. MDCCCXXVI. IV A synoptical view of the results afforded hy the observations Vol. for 1826 1824 1826 1826 1824 1824 1826 1824 1824 1824 I 217 3 288 I 365 I 218 292 3I293 star's Name, &c. Nova 70 p Ophiuchi 1824 3 1824 3 1824 3 1824 3 1826 I 1824 1826 219 294 296 296 297 S 698 H&S258 S. Re-exam. Nova S....699 H.C.362 H&S2S9 HI. 56 H&S260 Observer and Number. U. A. Decl. h. m. «7 54 17 56 17 56 i7 57 17 57 Nova ._. 73 ? Ophiuchi 100 Herculis.. Nova Struve, 569.. 1826 1824 298 299 299 219 3 1301 1I371 I. 86 H. C. 298 40 Ceph. or Drac. H.C.474 59 rf Serpent S 700 H&S261 H&S262 H&S263 H&S264 I 220 1826 i8z6 1826 1824 1824 1824 ,1826 1826 1824 1824 1824 303 H&S265 H&S266 H&S267 S 701 H&S268 S. Re-exam 18 18 18 18 18 22 30 S 2 33N 25 23 N 64 9 N 12 oN Position. Quadrant. Nova .... 39 Dracon. 372 373 220 305 305 1824 1824 1824 1826 1824 1826 1824 1826 1824 1824 1824 307 374 221 309 310 310 3'i 3^3 3H 375 315 221 I and 2 . I and 3. I and 2 . I and 3 . Nova . . . . H. C. 300 H. C. 294 S....702 H&S269 18 12 18 12 18 13 18 15 18 18 16 43 S 3 57 N 26 5N 18 49 S 18 38 S 47 27 64 48 58 3 53 17 15 27 12 21 S. Re-exam, S....703 H&S270 H&S271 18 20 18 21 18 25 18 30 18 30 25 28 N 15 10 S 71 s8N 6 41 S o 5N 84 38 12 23 87 35 77 52 37 22 tip «/ sp . np sp Remarks. «Lyr£ H&S272 S. Re-exam. S....704 H&S273 H&S274 H&S275 H.C. 87 . IV. 94... H. C. 296 5 Aquilae . 4» • Lyrx inter i and 5 Lyrae 5 L> rse 1^ Lyrae. Nova . . 1824 3 1826 I 1826 I 1826 I 1824 317 222 317 318 319 H&S276 H&S277 H&S278 S. Re-exam H&S279 S....70S 18 31 18 32 18 36 18 36 i8 37 19 13N 58 42 N 32 8N 52 13N 41 7N 82 48 5» 37 34 56 71 o 48 5 48 34 np sp nf,sp nf H.C. 170 . / Lyras . . . . (3 Lyrae H.C. 19? . 9 Serpentis , 1824 1826 1826 1824 1826 320 223 224 225 321 322 226 226 323 227 0 Draconis . . . . 1 1 Aquilae . . . . 11.93 1.58 P. XVIIL 274 1826 1824 1826 1824 1824 228 324 229 325 325 H&S280 S 706 H&S281 H&S282 H&S283 18 38 18 38 18 38 18 38 18 39 38 37 N 9 33N 34 32 N 10 39 S I 9S 76 51 86 5 68 5 84 40 68 36 66 9 4 34 70 15 np sp sp sp np np ip . 42 7 43 30 I 4 5 51 66 18 32 42 sp, nf nf nf nf sp . np np 39 27 N 39 27 N 39 27 N 37 25 N 34 22 N 18 42 18 42 18 43 18 48 18 48 H&S284 S....707 S 708 S....709 H&S285 15 Aquilse. Nova Nova . . . . IIL 109 . . 1-59 233 Bode Dracon. H. C. 19? Nova Prec. VI Lyrse I H &S 289 6 Bode Cygni H&S290 H&S286 S 710 S 711 H&S287 S 712 18 49 18 51 18 52 18 52 18 54 10 47 N 32 37 N 33 loN 33 46 N 3 58N 64 7 50 ± 69 56 69 II 59 51 68 12 18 56 18 57 18 57 18 58 18 58 59 loN 13 23N 14 41 N 36 iiN o 58S 85 28 33 58 60 I 80 15 14 26 */ nf np nf np> */ np, s 4 »7S 16 33 S 27 4S 6 53N 35 32N S....713 H&S 288 S....714 79 " 29 28 18 19 20 21 58 49 sp np np sp np np sf 30.922 . 4.266 ,.4.765 ■ 18.744 . 21.093 . . 6.748 Binary ; mean mot. — 6°. 8 11 ; not uniform Epoch 1825 56. Scarcely altered. 28.969 . 1.989 14.281 54-302 16.419 Distance increased. . 4.587 14.091 21.362 . 6.761 .4.151 . 4.465 ...6.288 ...3.599 I 30.201 ...3-593 1 28.939 . . . 6.433 . . 26.226 . . . 6.000 Unchanged. Binary ? Epoch 1825.54. Binary? mean mot. —o°.205. J Epoch 1825.55. 42.108 41.563 57-657 24.630 . 5.306 , 14.468 Changed in Pos. and Dist. by proper mot«, Epoch 1825.56. , . 4.010 .53 ± . . 3.801 . . 3.340 . 44.240 . . 4.492 Binary ? mean mot. — o°.i9. Binary ; mean mot. — o°.325. Epoch 1825.53. . 4.794 59.840 45-778 46.035 21.679 Change of Pos. = -{-5° 21'. 29-949 19.658 . 6.677 .5.478 , 26.019 No material change. Unchanged. Pos. changed 7° 21'; ann. mot. -{- o .173. 18 59 19 2 19 2 19 6 19 7 75 33N 34 18N 34 28 N 38 44N 49 31 N detailed in the present, and preceding communications. Vol. for 1824 1826 1826 1824 1824 Star's Name, &c. Observer and Number. R. A. 1826 1824 1824 1824 1824 326 229 230 328 231 329 330 352 Lyras . , Nova . . , Nova . . . fl Lyrae . . H.C. 90. 1826 1826 1826 1826 1826 1826 1824 1826 1824 1824 }24 231 232 233 233 234 235 28 Aquilae. H. C. 1 1 1 . 111.57.... II. 69 $ Cygni... H&S291 S....715 S....716 H&S292 H&S293 S....7,7 H&S 294 H&S295 H&S 296 H&S 297 1824 1824 1826 1824 1826 1826 1824 1826 1824 1826 1824 1824 334 236 335 336 336 n. 99 Nova A and B. AaiidC. »3 Sagitta: H.C. 116 b. 19 19 »9 ^9 Decl. 19 II 19 18 19 19 19 21 19 24 S. S., ..718 ..719 s. S. S. .720 ,721 722 19 25 19 25 38 5IN 16 I5S 16 I4S 37 49 N 5 16N Quadrant. 12 iN 9 54S 20 46 N 36 loN 27 35 N 5 58 74 33 70 51 17 52 87 46 85 6 35 49 63 26 23 16 35 15 nf «/ sp np Distance. 29.336 .9.176 . 6.286 41.665 31.420 Remarks. 27 54 N 36 21 N 337 338 236 339 376 237 151 Bode Aquilag. f-9i 1 6 Cygni Struve, 634 Nova I and z .... 1 and 3 339 238 340 377 340 342 1826 1826 1824 1824 1824 1824 1826 1826 1826 1824 Struve, 635 Struve, 636 i and 2. I and3. Nova ^ Cygni , H&S 298 S 723 H&S 299 H&S 3C0 H&S 301 H&S 302 H&S 303 V. 137. X Cygni.. Nova . . . . w Aquilas. ^ Sagittae . » Aquilx. 238 II. 95. 239 III. 112. 343 57 Aquilae. 344 Struve, 647. 345 {1 Draconis. S....724 H&S 304 S. Re-exam, S....725 19 27 19 29 19 29 19 34 19 36 19 37 19 38 19 38 10 33 S 16 4N 17 19S 19 38 '9 38 H&S 305 S 726 H&S 306 S. Re-exam. H&S 307 H&S 308 '9 39 ^9 39 '9 39 346 4/ Cygni 240 JNova ; A and B .... A and C "/xSagittffi Nova I. 96 I and 2 .... 1 and 3 S....727 S....728 H&S 309 H&S 310 H&S 311 241 241 348 1824 349 1824 1824 1826 1826 1826 1826 1826 1826 1824 3 351 352 243 243 244 244 245 246 247 353 H. Nova Nova Nova Nova C. 16 J I and 2. I and 3 . H&S 312 S 729 19 40 19 40 19 41 19 41 19 42 8 43 S 10 21 N 50 6 N 33 14N 33 HN ^5 38 33 27 24 46 46 3 857 32 45 np,sf ff, sp 59.280 11.314 . 6.938 • 7-430 34-383 n 52 N 35 39N 20 30 N 44 42 N 34 37 N 56 34 6 27 45 13 56 15 15 56 57 35 »9 43 19 43 »9 45 19 45 19 49 20 N 27 N 22 N 18 43 N 8 24N S 730 S 731 H&S 313 H&S 314 II. 70 V. 136 9Sagittae A and B... AandC... Nova II. 96 .*.' H&S 315 H&S 316 S 732 ^""133 19 51 19 52 19 52 '9 53 19 56 o 2N 43 55 N 8 42S 19 53N 69 48 N 68 30 36 52 1 ' ? 34 Single. Single. 60 49 nf nf np nf sp 6.840 . . . . 6.295 . . . 53.228 4.488 .1 31.913 . . . 10.669 Sir W. H. has no measures of this star. Changed + 4° 50' in Pos. ; Dist. unaltered Changed + 5° 56' in Pos. Unchanged. np np,sf np nf 37.112 • 3-994 37-504 25.871 16 42 63 30 45 27 33 27 44 32 55 48 nf sp sp nf 51 58N 35 3N S....734 S....735 S....736 S....737 H&S 317 20 20 20 20 17 7N 46 5 N 35 32 N 26 42 70 23 81 8 58 30 8c 21 35 18 N 88 o 25 47 34 12 74 10 63 24 86 52 59 29 sp np np .2 11.936 »5-i33 19.831 . 5.122 38.745 Probably unchanged. Probably annual motion = + 0^.148. Unchanged. Probably a slow change of Pos. Probably unchanged. 25-503 33.444 . 1.957 1825. No material change. np */ np,sf np Probably unchanged. have been 35°.27' sf (S.) Micrometer read off incorrectly; should 1.549 [Epoch 1825.61. Unchanged. 8.818 JBinary? mean motion. 2 33-375 • 5.587 10.415 36.158 42.427 . 2.590 sp np sp nf sp, nf */ np Common proper motion. No sensible variation. Unchanged. Probably unchanged. Pos. unchanged. 20 20 20 20 20 35 >7N 35 7 N 20 36 N 34 57 N 16 16N o 40S 20 22 N 20 25 N o 19N 30 58 61 48 33 26 54 3 71 o 32 48 75 24 07 43 57 58 43 II 39 24 61 48 np nf sp np np np nf sp np sp sp ....4.321 ....4.318 .4 2.884 •I 55-931 5.992 * ' * '41.335 \ Hardly changed in Pos. 10.793 36.523 20.164 9-479 .4.518 • 5-355 . . . . 6.605 . . 54.670 ... u 777 I 10.088 I 41.069 ... 4,100 j Perhaps a slow change in Pos. Probably unchanged. Unchanged. Distance unchanged. Posit, not given by [Sir W. H. XVI A synoptical view of the results afforded by the observations Vol. for 1826 1826 1826 1824 1826 1824 1826 1824 1826 1826 247 248 248 354 I249 star's Name, &c. Observer and Number. 1826 H.C.297 Nova P.XX.43,44 H.C. 182 Nova ; A and B . . . AandC. 355 250 413 251 251 « Capricorni 0* Cygni. . . . a- Capricorni 32 Cygni... Nova S....738 S....739 S....740 H&S318 S....74> R. A. Decl. Position. Quadrant. b. 20 20 20 20 I20 33 7N 6 33S 6 4N 4 2 S 21 45 N H&S 319 S 742 H&S 380 S....743 S....744 1826 1824 1826 1824 3 1826 1826 1826 1824 252 253 355 258 259 356 379 ^ Capricorni A and B A and C H.C. 240 1.95 Nova; A and B . BandC. Cephei 1824 1826 1826 1826 1826 254 255 358 359 •745 20 8 20 8 20 9 20 10 20 II S....746 , H&S 320 I S....747 H&S 321 S. Re-exam. 20 II 20 12 20 14 20 14 20 15 13 3 S 46 12N 19 40 S 47 loN 12 28N H.C. 176 P. XX. 140 p Capricorni. VI. 29 . . 11.51.- 361 0 12 Capricorni 255 Nova S....748 S....749 H&S 322 H&S 323 H&S 324 |20 20 S 750 120 22 15 21 S 45 4N 54 48 N 15 50N 77 loN 22 15 39 26 77 II 36 33 86 13 60 12 21 26 83 53 86 27 85 34 52 51 20 i» 20 18 20 19 20 20 I 1256 I 256 I 257 1824I 3I362 1826 1826 1826 1826 1826 1826 15 Bode Delphin.. . S 751 H.C. 537 S....752 37 Bode Cephei S 753 H.C. 109 \ll8cS 325 1824 1826 1826 1826 1824 I 258 I 259 I 260 I 261 I 261 210 Bode Cygni. u^ Cygni Nova H.C. 114 IV. 92; AandB. 20 22 20 22 20 22 20 23 754 20 23 13 44 S 2 42 S 18 24S 18 24S 19 loS 25 48 N 2 54 43 40 43 28 69 39 61 40 17 ± 38 4 36 24 sp, nf sp % Distance. np np . 41.862 . 25.116 .43.893 . . 14.491 . . . 6.439 ••57-325 Remarks. 12.999 46-393 53704 28.496 28.383 Pos.changed8°53'. 23 25 80 35 60 45 87 »7 30 17 54 >3 sp np S....755 S....756 S....757 S....758 S....759 262 A and C. 20 25 20 26 20 26 20 27 20 28 10 45 N 18 48N 56 3N 10 35N 25 53N 13 35 18 38 29 38 14 22 31 H sp */ sp np 3 23.715 3 46716 ...8.915 ... 3.980 - • 30.745 ....13 ± 8.138 \ No measures given by Sir W. H. Each by estimation. Distance increased 3''. . 7.871 Epoch 1825.67. . . 23 803 .. 59.872 3 58.021 ... 4.026 , . . 22.060 . I 6.711 48 37 N 48 37 N 27 31 N 13 21 S 14 8N 1826 362 262 263 263 3 363 Nova ' H. C. 106 , Nova 52 Cygni 7 Delphini 1 and 2. . H & S 327 I and 3 . H&S 326 20 32 S 760 20 34 S....761 S 762 20 37 20 37 20 38 38 5N 12 6N 23 17N 30 4N 15 29N 8 49 49 I 31 33 73 49 19 58 52 55 np sp np np np np sp sp 14.689 45-377 26.446 15.484 25.674 Pos. changed 3° 53' ; Dist. increased 2".6. 1.387 55.791 . 4.468 10.256 25.083 • 54-299 3 1I264 iH.C. 177 1 S. I1826 I 264 ir. 66 S. 1826 I 266 X Cygni S. 1826 I J266 Nova S. 1826 I I267 jll. 100. 1 s. •763 .764 .765 .766 .767 20 38 20 38 20 40 20 42 20 43 18 51 S 15 14N 35 50N 88 43 3 o 61 56 32 40 3 43 78 35 25 6 84 59 14 29 np nfysp np «/ np Unchanged. • 9-478 .9.194 . 2.049 I . 7.202 [Unchanged. 12.317 .2 20.857 5 46 N 69 31 51 17NI 15 24 np np ^f np nf I1826I1I268 P. XX. 355 L?;-c"^ Q r ^^ I1824 3I364 UEquulei H&S 328 20 50 1826 I I268 Nova ._.... S. .. .769 I20 50 1826 I 269 280 Bode Cygni S. I18261 I 270 Nova ' S. 6 40N 3 36N . . , . 15 47N 770 20 53 49 46 N 771 |20 55 1 6 30S 54 44 10 39 14 2 57 9 78 20 sp nf sp 16.749 . 4.979 25.590 • 3-998 . 4 409 Change of Pos. 6° 17'. Unchanged. Unchanged. 40.598 12.374 14.987 2.449 • 3.227 Pos. changed — 10^ 45*. I1826I1 1271 jNova 1 S..^^772 20 56 1826 1 272 Struve, 704 S 773 20 57 18243 365 61 Cygni LKi^^329 20 59 I1826 1 381 S. Re-exam. .... I1826 1 272 Nova S 774 i20 59 !j826! I 273 II. 97. .••. S 775 21 2 51N 34 44 N 37 52N 33 26N 29 29 N 59 31 59 54 5 J9 3 4 47 9 45 12 "/ nf sp np .3.613 23.249 15.425 15.444 14.324 I . 3.576 Unaltered Binary ; mean mot. + 0°. 730. Epoch 1825.70. detailed in the present, and preceding communications. Vol. for Star's Name.&c. Observer and Number. Decl. Position. Qoadrant. Distance. Remarks. 1826 1826 1826 1826 1826 1826 1826 1826 1826 1826 1826 1826 1826 1826 1826 1826 1826 1826 1824 1824 1826 1826 1826 1826 1826 1824 1826 273 274 276 276 Struve, 709. 1789.213 — Nova Struve, 710 Nova ....-.-.. 277 278 279 280 281 19 Bode Equulei ^Equulei H.C. 197 Nova Struve, 718. . . . 281 282 283 283 284 327 Bode Cygni I Pegasi H.C. 197 Nova 69 Cygni 284 285 285 369 370 Nova . . . Nova . . . Nova . . . jS Cephei 3 Pegasi. 286 287 Nova . III. 71 288 288 289 AandB. . A and C 76 Cygni III. 72. Pegasi 370 /* Cygni 1824 1824 1824 289 290 373 374 375 . . I and 2 . . I and 3 79 Cygni; A andB.^ , A and C . - '45-74-^ I4S-S7- ni.74 S... s... 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 H&S330 H&S331 794 795 79^ 797 798 H&S332 S....799 H&S333 H&rS334 H&S335 m. 2 2 2 2 2 43 N 26 N 50 N iN 16N 30 53 32 3» 5 55 79 15 58 20 4 6 7 II 13 6 28N 9 17N 8 23S 8 48N 52 15 N 82 58 4« 3 82 22 84 53 26 33 13 H H 18 18 52 19N 19 3N 7 20S 12 56N 35 33 N 32 22 40 II 6 30 56 29 II 22 20 24 25 26 28 10 19 N 33 2N 19 56N 69 46 N 5 48N 68 5 79 23 41 40 19 35 78 58 3» 33 34 35 35 36 '36 "46 46 49 35 3;N 56 41 N 39 S9^ 56 46 N 9 3N 72 3 31 33 69 3 40 52 33 35 52 59 27 56 N 3-7 29 N 18 *sVn 54 59N 5 6N 23 4 28 43 30 39 50 8 20 15 76 u 33 29 np np sp,nf «/ nf, sp ..17.685 .. 6.825 ...3.087 » 54-785 ...2.933 np «/ sp sf, np 3 3-24» . . 26.240 . . . 4-837 . . . 2.642 . . . 6.641 Annual mot. =— o*» 838 in Pos. &+o". in Dist. np np sp 48.739 36.861 36.784 . 3-480 40-305 np, sf sp,nf np sp np np sp «/ np . 1. 195 .4.321 . 2.580 13.163 39-525 No notable change. Perhaps a very slow change of Pos. . 8.172 11.945 19-383 5.645 12.150 18.514 Change of Pos. —3° 51', of Dist. +0''.^ Ch. of Pos. — 4°.54 & +o".77 in Dist! Sir W. H. has no measures of this stai Pos. unchanged. «/ «/ np sp ... 5.744 .3 37.401 .2 33.170 2 J min. ±: . . . 22 052 .. . 20 308 . . 10.093 Diminished ia Distance. 1824 1826 1826 1826 iS26 375 290 291 291 292 Near III. 74 1789.213 ... H.C. 571... 29 Aquarii. . Nova H&S336 S 800 S 8oi S 802 S....803 49 49 52 53 57 5 6N 61 45 N 12 51 S 17 49 S 12 48 N 1824 1826 1826 1824 1824 376 292 293 376 377 I Cephei 1789.218 Nova P. XXII. 1 1. 12 '45-56 H&S337 S 804 S 805 H&S33S H&S339 21 58 22 o 22 o 22 3 22 4 63 45 N 69 20 N 36 45 N 58 25 N 21 53S 1826 1826 1824 1824 1826 1824 1824 1826 1824 1824 1824 1826 293 294 378 378 382 379 380 295 381 382 383 383 180 Bode Cephei. Nova , 145.120 , I Lacertae 33 Pegasi. S 806 S 807 H&S 340 H&S341 S. Re-exam. H&S 342 22 22 22 2Z 22 15 81 58N 28 41 N 69 17 N 36 5iN 19 56N Struve, 751 Nova ...... 145.64..... 53 Aquarii. . ^ Aquarii. . . H&S 343 S 808 H&S 344 H&S 345 H&S 346 S. Re-exam. 22 16 22 16 22 17 22 17 22 20 65 50 N 21 5 S .44 27 N 17 39 S o 57S 44 o 55 21 30 4 26 38 7 9 sp */ sp sp,nf I 45.858 I 2.836 . . 20.453 ..4.370 ..,. 3.288 23 »5 83 43 22 40 45 13 30 42 np «/ np • 5-817 16.606 12.774 22.094 . 5.170 8 15 »5 3» 78 43 II 45 12 21 77 75 */ sp sp sp np 13-567 . 1.794 14.839 15.619 »5-732 56.045 Epoch 1824.84. 2 37 64 35 o 5 3 7 89 29 88 56 «/ nf np sp nf . ^723 • 6.457 . 4-238 10.032 . 4.989 . 4.014 Binary ; mean mot. — 0*^.4484. Epoch 1825.73. MDCCCXXVI. A synoptical view of the results afforded by the observations , &c. 385 295 296 386 296 297 297 298 299 387 star's Name, &c. a Ccphei Nova H.C. 108 8 Lacertse i and 2 , 1 and 3 . Struve, 758 H.C. 181 10 Lacertae Nova 12 Lacertze 213 Bode Aquar. . 299 300 388 301 301 302 389 303 303 39^ 1789.219 . . . . 1 6 Lacertae . . Nova Nova P. XXII. 306 n Pegasi t' Aquarii 231 Bode Aquar. 1&2 I and 3 Aquarii Nova Observer and Number. H&S347 S 809 S 810 H&S348 S 811 S 812 S 813 S 814 S 815 H&S349 S....8I6 S....8I7 H&S350 S 818 S 819 S 820 H&S35I S 821 S 822 H&S 352 h. m. 22 23 22 24 22 25 22 28 22 29 22 30 22 31 22 33 22 33 22 34 22 35 22 38 22 39 22 40 22 41 22 42 22 48 22 50 22 57 22 59 Decl. 57 30 N 6 31N 3 19N 38 42 N 37 57 N 28 S 7N 7N 17N II S 17N oS 9S 33' s 23 N 71 56N 40 39 N 26 49 N 32 26N 31 5'N 78 44 79 41 55 35 85 39 55 15 6-/ 26 56 46 41 19 9 42 73 28 51 19 68 56 22 47 24 24 72 33 22 24 20 31 9 21 44 41 82 II 70 48 58 19 Quadrant. Sp np, sf */ sp np sf,np np,sf np np sp */ np np,sf np nf nf . 41.612 . 12.897 . 14.062 . 22.674 22.520 .21.175 . . . 6.01 1 I 0.444 . . 18.522 I 12.073 . . . 3-398 29.823 30-536 • 4.349 57-381 13-438 • 3-712 Sir W. H. has no measures of this star. DifF. of Pos. 2° 53'; dimin. of Dist. 5".!. Pos. changed 3° 54'. 0.895 4.541 . 6.850 • 3.434 . 8.716 Remarke. No material change. Unaltered. 39» 304 304 305 305 H. C. 242 2 Cassiopeiae H.C. 191 Nova H.C. 191; AandB. AandC. H&S 353 S....823 S 824 S 825 S 826 23 2 23 2 23 2 23 2 *3 5 46 59 N 58 21N 12 54S 35 55 N 9 52S 17 o 73 20 12 41 49 58 86 10 19 10 sp sf np 14.709 46.683 . 4.207 5-331 26.276 38.168 Sir W. H. gives no measures of this star. 306 392 307 308 308 4'' Aquarii . . . 94 Aquarii . . . Nova P. XXIII. 69. xPiscium. . . . S 827 H&S 354 S 828 S 829 S....830 23 6 23 10 23 13 23 H 23 18 10 4S 14 26 S 34 29 N 9 27S o 16N 41 8 76 41 86 13 4 4 74 56 np . np sp np np 49-835 14.993 .5.117 . 7.981 30.090 Probably not Sir W. H's. star. Sir W. H. has no measures of this star. 308 393 309 310 393 Struve, 783.. . Anonyma II. 94 or Nova ? H.C. 128 107 Aquarii. . . . S....831 H&S 355 S 832 S....833 H&S 356 23 21 23 22 23 23 23 32 23 37 4 17N 57 32N 42 50 N 5 17N 19 41 N 84 1 o o 41 52 41 34 53 30 sp P np np 11.681 13953 . 4-389 H-575 . 5.056 Pos. changed probably 6° 42', if II. 94. 310 3" 394 IV. 107 20 Piscium 28 Bode Andr. 1 & 2 I and 3 S....834 S....835 H&S 357 395 3" Nova H&S 358 S....836 23 38 23 39 23 43 23 46 23 49 27 28 N 3 46S 36 54 N 30 52 N 23 22 N 396 397 312 312 T Cassiopeiae .... 37 Bode Androm. Struve, 794. . . . 9 Cassiopeise .... H&S 359 H&S 360 S....837 S....838 23 50 23 51 23 54 23 55 54 45 N 32 43 N 65 6 N 61 17N 53 31 17 »3 0 »7 45 25 59 11 44 38 57 4» 81 38 19 24 74 23 nf np p,nf np np 32.248 50.924 . 5.011 45.941 41.297 . 9.361 Differs 3° 10' from Sir W. H's. Pos. np sp nf sp . 2.924 . 5.263 15.427 5-423 Doubtful if changed or not. Manifestly not Sir W. H's. star. Sloaiie Street, No. 132, April 1 2th, 1826. JAMES SOUTH. A careful revision of the former communication on Double Stars, Phil. Trans. 1824. iii. has led to the detection (among several errata of trifling importance), to the following of a graver character, which the reader of that paper is earnestly requested to correct in his Copy. Page, &c. Error. Correction. 124. 216. 325- 337. .Mean 54Cancri. . 48.845- • 4-13 .Near 54 Cancri. 40.845. 44.6.., 337 twice and in Index, Star No. 301 338 355 167 and in Index No. 144. 101 and in Index No. 79 323 twice and in Index No. 287... Index No. 105 , . . . . Index No. 110 in Column of Decl. Index No. 278 Index No. 222 , { 97.60 .23.467.. Z= + 1.44... Z = — 0.12. . . .-.73° 50' ••••73 54 ••••73 52 ....i6".988 ....67° 46' 9 42 ... .12 17 ...278 Mean mot. — 2°. 13 107.60. .. 25.871.. .Z = — 1.44... .Z = + 0.12... ••••72° 50' ••••72 54 ••.•72 52 ....i5''.966 22° 14' 9 iz ... .17 12 ..•278 Mean mot. + 2°. 13 ^n^ata to be corrected in the present Memoir^ Page 209, /or " between 36 and 38," read north following 36. 353>/o^" 1825.252," rejrf 1825.52. vi. (Index) H. and S. 74 ; for -f o°.oo9," read + 0°. 109. viii. (Index) S. 600 ; Re-exam, add in col, of Remarks, the word '« Binary. From the Press of JV. NidOL, Cleveland-row, St, Jameses. PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON. FOR THE YEAR MDCCCXXVI. PART II. LONDON: PRINTED BY W. NICOL, SUCCESSOR TO W. BULMER AND CO. CLEVELAND-ROW, ST. JAMEs's; AND SOLD By G. AND W. NICOL, PALL-MALL, PRINTERS TO THE ROYAL SOCIETY. MDCCCXXVI. Cv3 ADVERTISEMENT. . 1 HE Committee appointed by the Royal Society to direct the publication of the Philosophical Transactions, take this opportunity to acquaint the Public, that it fully appears, as well from the council-books and journals of the Society, as from repeated de- clarations which have been made in several former Transactions, that the printing of them was always, from time to time, the single act of the respective Secretaries^ till the Forty-seventh Volume : the Society, as a Body, never interesting themselves any further in their publication, than by occasionally recom- mending the revival of them to some of their Secretaries, when, from the particular circumstances of their affairs, the Transactions had happened for any length of time to be intermitted. And this seems principally to have been done with a view to satisfy the Public, that their usual meetings were then continued, for the improvement of knowledge, and benefit of mankind, the great ends of their first institution by the Royal Charters, and which they have ever since steadily pursued. But the Society being of late years greatly enlarged, and their communications more numerous, it was thought advisable that a Committee of their members should be appointed, to reconsider the papers read before them, and select out of them such as they should judge most proper for publication in the future Trafisac- tions ; which was accordingly done upon the 2()th of March, 1752. And the grounds of their choice are, and will continue to be, the importance and singularity of the subjects, or the advan- tageous manner of treating them ; without pretending to answer for the certainty of the facts, or propriety of the reasonings, contained in the several papers so published, which must still rest on the credit or judgment of their respective authors. It is likewise necessary on this occasion to remark, that it is an established rule of the Society, to which they will always adhere, never to give their opinion, as a Body, upon any sub- ject, either of Nature or Art, that comes before them. And therefore the thanks, which are frequently proposed from the Chair, to be given to the authors of such papers as are read at their accustomed meetings, or to the persons through whose hands they received them, are to be considered in no other light than as a matter of civility, in return for the respect shown to the Society by those communications. The like also is to be said with regard to the several projects, inventions, and curiosi- ties of various kinds, which are often exhibited to the Society; the authors whereof, or those who exhibit them, frequently take the liberty to report, and even to certify in the public news-papers, that they have met with the highest applause and approbation. And therefore it is hoped, that no regard will hereafter be paid to such reports and public notices; which in some instances have been too lightly credited, to the disho- nour of the Society. CONTENTS. I. An Account of the construction and adjustment of the new Standards of Weights and Measures of the United Kingdom of Great Britain and Ireland, By Captain Henhy Kater, F,R, S. - - - - page i n. description of an improved -Hygrometer. By Mr. Thomas Jones. Communicated by Captain Henry Kater, F.R. S. 53 III. Observations on the changes which have taken place in some aritient alloys of copper. By John Davy, M D. F. R. 5. In a Letter to Sir Humphry Davy, Bart, Pres,R, S, -55 IV. Additional proofs of animal heat being influenced by the nerves. By Sir Everard Home, Bart, V, P, R, S. 60 V. The Croonian Lecture. On the structure of a muscular fibre from which are derived its elongation and contraction. By Sir Everard Home, Bart. V. P. R.S. - - 64 VI. An account of the heat of July, 1825 ; together with some remarks upon sensible cold. By W. Heberden, M, D. F.R,S. - - - - -69 VII. On the transit instrument of the Cambridge Observatory ; being a Supplement to a former Paper, By Robert Wood- house, Esq, Plumian Professor of Astronomy in the University of Cambridge, - - - - 75 VIII. Account of a series of observations, m^de in the summer of the year 1825, for the purpose of determining the difference of meridians of the Royal Observatories of Greenwich and Paris ; drawn up by J. F. W. Herschel, Esq. M, A. Sec. R. S. Communicated by the Board of Longitude, - - 77 IX. Observations on the poison of the common toad. By Johjt Davy, M. D. KR.S. - - - page 127 X. On the magnetizing power of the more refrangible solar rays. By Mrs. M. Somerville. Communicated by W. Somerville, M. D. F. R. S. Feb. s. 1826, - - 132 XI. On the mutual action of sulphuric acid and naphthaline, and on a new acid produced. By M. Faraday, F. R. S. Cor^ responding Member of the Royal Academy of Sciences ^ &c. ^c. Communicated January 12, 1826, - -- 140 XII. On the nervous circle which connects the voluntary muscles with the brain. By Charles Bell, Esq. Communicated by the President, January 25, 1826, - - - 163 XIII. On the constitution of the atmosphere. By John Dalton, Esq.F.R.S. - 174. PHILOSOPHICAL TRANSACTIONS. I. An Account of the construction and adjustment of the new Standards of Weights and Measures of the United Kingdom of Great Britain and Ireland, By Captain Henry Kater, F. R. S. Read November 24, 1825. Ike weights and measures of the United Kingdom of Great Britain and Ireland are founded upon a standard, the length of which is determined by the proportion it bears to that of the pendulum vibrating seconds of mean time in London. The length of this pendulum I have stated to be 39,13929 inches of Sir George Shuckburgh Evelyn's standard scale; and the experiments from which this con- clusion is deduced, are detailed in the Philosophical Transacr tions for 1818. The important consequences, however, which attach to this result, render it necessary to examine with what degree of confidence it may be received. In the Paper to which I have alluded, it is mentioned that a series of experiments had been made previous to those detailed ; the result of which was rejected, in consequence of its being discovered, after their completion, that the steel MDCCCXXVI. B 2 Captain Kater*s account of the plates, on which the pendulum had rested during the expe- riments, had suffered penetration by the knife edges. The length of the seconds pendulum however, deduced from these first experiments, did not differ more than two ten- thousandths of an inch from the final determination. It may also be seen, that in repairing the knife edges after the first set of experiments had been concluded, one of them was broken ; and when replaced by another, the distance between the knife edges was increased about one hundredth of an inch ; so that two results, differing by so small a quan- tity from each other, may be considered as having been obtained by two different instruments. The Philosophical Transactions for 1819 contain an account of experiments for determining the variation in length of the seconds pendulum at the principal stations of the Trigonome- trical Survey of Great Britain. For this purpose I constructed an invariable pendulum, the number of vibrations made by which being observed in London, and also at the principal stations of the Trigonometrical Survey, the length of the seconds pendulum, at such stations, could readily be deduced from the previously known length of the pendulum vibrating seconds in London. In this manner, the length of the pendulum vibrating seconds at Unst was found to be S9,i7i46 inches, and at Leith Fort 39,15554 inches. The " Reciieil d' Observations Geodesiques /' &c. which may be considered as a fourth volume of the " Base du Systeme metrique," affords me an opportunity of comparing these last results with those of M. Biot, whose very valuable labours for determining the length of the pendulum vibrating new standards of weights and measures. 3 seconds at various stations, from Unst to Formentara, are there detailed. In these experiments M. Biot employed the method of Borda, which requires that the absolute length of tlie pendulum should be obtained by actual measurement at each station. M. Biot's observations and mine, both at Unst and Leith Fort, were made at the same stations ; and M. Biot found, from the mean of fifty-six series, using different measuring rods and various pendulums, the length of the second pendulum at Unst to be ,994943083 metres, and at Leith Fort ,994524453 metres. Converting these results into inches of Sir George Shuck- burgh's scale, by taking the length of the metre at 39,37079 inches, as given in the Philosophical Transactions for 1818, we have the length of the seconds pendulum at Unst, after reduction to the level of the sea, 39,17176 inches, and at Leith Fort S9A55S9 inches, the first differing from my determination +,00029, and the latter —,00015 of an inch. The difference of results obtained by methods totally dissi- milar being so small, and with contrary signs, it may be reasonably inferred from them, as well as from what has been before advanced, that the length of the pendulum vibrating seconds in London has been determined to within one ten-thousandth of an inch of the truth. From the near agreement of the results of the French and English experiments on the length of the pendulum, it may be inferred that the length of the French metre, expressed in parts of Sir George Shuckburgh's scale, is probably not erroneous one ten thousandth of an inch. From an account recently published by Captain Sabine, F. R. S. of his valuable experiments for determining the vari- ^ ' Captain Kater's account of the ations in length of the seconds* pendulum, doubts may be inferred of the accuracy of the method which I employed in the observations for ascertaining the length of the seconds* pendulum in London, as well as in those which have been made with the invariable pendulum. It is asserted, that taking a mean between the disappearance and re-appearance of the disk, is a more correct method of observation than that which I have pursued ; and that the intervals between the coincidences obtained by observing the disappearances only of the disk, would be productive of error. With respect to the convertible pendulum, it will be seen on referring to the Philosophical Transactions for 1818, that the disk was made to subtend precisely the same angle as the tail-piece of the pendulum ; so that at the moment of disap- pearance of the last portion of the disk, its centre coincided with the middle of the tail-piece, a circumstance which, in my method of observing is indispensable, when the object is to obtain the true number of vibrations made by the pendu- lum in twenty-four hours. With the invariable pendulum, from causes unnecessary here to detail, the circumstances were somewhat different, the disk subtending a less angle than that of the tail-piece of the pendulum ; in consequence of which, the interval between the apparent coincidences was lessened, and the inferred number of vibrations in twenty-four hours diminished about two- tenths of a vibration ; but as the experiments with the inva- riable pendulum are intended to be merely comparative, and should therefore be made as nearly as possible in every respect under similar circumstances, no part of the apparatus being changed, nor any alteration made in the pendulum of new standards of weights and measures. 5 the clock, this constant difference of the number of vibrations from the truth will not affect the ultimate deductions. As the most direct method of removing any doubts which may be entertained upon this subject, I shall add a comparative Table of the successive differences of the number of vibra- tions in twenty-four hours, which I have computed from the whole of Captain Sabine's observations, by employing the disappearances only, of the disk. Differences by the method of disappearances. Differences by the method of dis- appearances and re- appearances. Difference of the results. Stations. Vibrations. Vibrations. Vibrations, St. Thomas Maranham Ascension . Sierra Leone . Trinidad . Bahia . . Jamaica New York London Drontheim Hammerfest Greenland . Spitzbergen 9>62 i3>29 4.97 0,85 S'S^ 12,40 72,72 41,88 38,62 22,48 9'53 12,62 9,62 13.33 4.97 0,83 5.50 12,46 72,71 4i>8i 38.73 22,44 9,48 12H.9 0,00 — 0,04 0,00 -1-0,02 + 0,01 — 0,06 + 0,01 + 0,07 — o,ii + 0,04 -j-0,05 -Ho,oi Mean . . 0,00 As the comparative results, by the method of disappear- ances, would to a certain degree be vitiated by the use of a disk of a different size, the observations made in London in 1824 with a silver disk are omitted. The differences of the results being so minute, and the mean of the whole being absolutely nothing, the conclusion i& warranted that the method of observing coincidences by 6 Captain Kater's account of the disappearances alone is productive of no error, if the ob- servations are made as nearly as may be under similar circumstances. With respect to the absolute length of the pendulum in London, as determined by means of the convertible pendu- lum, it must be evident from what has been advanced, that the method of observation by disappearances alone could, on that occasion, have been productive of no error, as the disk subtended precisely the same angle as the tail-piece of the pendulum. In the Philosophical Transactions for 1821 will be found " An account of the comparison of various British Standards of linear measure \" and it will there be seen that the differ- ence between Sir George Shuckburgh's standard scale and a standard yard of 1 760, made by Bird, and in the custody of the Clerk of the House of Commons, is so very small, that they may be considered as " perfectly identical." This yard, under the denomination of " the Imperial Standard Yard,'' has been declared by Parliament, on the recommen- dation of the Commissioners of Weights and Measures,* to be the " unit, or only standard measure of extension" of the United Kingdom ; consequently, the length of the pendulum before given is expressed in parts of the Imperial Standard Yard. The measures of capacity being dependant upon the weight of a cubic inch of distilled water, it became necessary to * A commission was appointed by letters patent under the Great Seal of the United Kingdom in 1818, '* For considering how far it might be practicable and advisable to establish a more uniform system of Weights and Measures," the members of which were, the late Sir Joseph Banks, Sir George Clerk, Mr. Davies Gilbert, Dr. W. H. WoUaston, Dr. Thomas Young, and Capt. Henry Kater. new standards of weights and measures. ^ consider the degree of reliance which might be placed upon the accuracy of the experiments made by Sir George Shuck- burgh on this subject. A cube, a cylinder, and a sphere of brass were used in these experiments ; and in consequence of some difficulties which occurred, the weight of these, both in air and in dis- tilled water, was so repeatedly ascertained by Sir George Shuckburgh, as to leave no reasonable doubt of the accuracy of his conclusions. But as the linear dimensions of the cube, sphere and cylinder, might not have been determined with equal precision, it was thought adviseable to repeat these measurements. This was accordingly done ; and though in detail they differed somewhat from Sir George Shuckburgh's determinations, yet, fortunately, the variations were such as nearly to counterbalance each other, and to occasion little difference in the ultimate result, as may be seen in an account of these last mentioned measurements given in the Philoso- phical Transactions for 1821, Sir George Shuckburgh's results having been expressed in terms derived from the mean of several standard Troy weights, of one and of two pounds, kept at the House of Commons, the Commissioners of Weights and Measures thought it desirable that the Troy pound, which differed the least from this mean, should be taken as the unit of weight ; and therefore recommended that the Parliamentary Standard Troy pound of 1758 should remain unaltered; and this has been accordingly declared by the Legislature to be the ori- ginal " unit, or only standard measure of weight, from which all other weights shall be derived ;" and that it is to be denominated '* the Imperial Standard Troy Pound." 8 Captain Kater's account of the From Sir George Shuckburgh's data, and the before- mentioned measurements of the cube, cylinder and sphere, the Commissioners of Weights and Measures determined the weight of a cubic inch of distilled water, weighed in air by brass weights at the temperature of 62° of Fahrenheit's thermometer, the barometer being at so inches, to be equal to two hundred and fifty-two grains, and four hundred and fifty-eight thousandth parts of a grain, of which the Imperial Standard Troy pound contains five thousand seven hundred and sixty ; and also that the avoirdupois pound, which has long been in general use, though not established by any act of the Legislature, is so nearly seven thousand grains, that they recommended that seven thousand of such troy grains be declared to constitute a pound avoirdupois.* The Commissioners of Weights and Measures also recom- mended that the gallon measure should in future be that which contains ten pounds avoirdupois of water in ordinary circumstances (that is to say, the temperature of the water being 62° of Fahrenheit's thermometer, and the barometer SO inches) ; and this, under the denomination of " the Impe- rial Standard Gallon," was declared to be the unit and only standard measure of capacity, and that eight such gallons should be a Bushel. The Act for " ascertaining and establishing uniformity of " Weights and Measures" having been passed by Parliament, to the effect before-mentioned, the Lx)rds Commissioners of His Majesty's Treasury expressed their hope, that some of * For the manner in which the weight of a cubic inch of distilled water was deduced, see the Appendix to the Third Report of the Commissioners of Weights and Measures. new standards of weights and measures, g the Commissioners of Weights and Measures would afford their assistance in directing the executive measures necessary for the accomplishment of its objects. In compliance with this request, I undertook to superintend the construction, and to adjust the principal standards to be deposited at the Exchequer, Guildhall, Dublin, and Edinburgh. Mr. Troughton, the first of our English artists having, in consequence of his advanced age, declined undertaking to make the standards, I directed Mr. Dollond to prepare those of linear measure ; and employed Mr. Bate, an artist who, as hydrometer maker for Revenue purposes, had been accus- tomed to nice operations in weighing, to construct those of weight and measure. Brass being peculiarly liable to decomposition in the atmosphere of London, I directed Mr. Bate to make some experiments, to ascertain the proportions of tin and copper which might produce a metal equal in hardness, and which might be worked with the same facility as hammered brass ; and after some trials it was found that a mixture of 576 parts of copper, 59 of tin, and 48 of brass, afforded a beautiful metal, which possessed the qualities I sought. In order to avoid any innovation but such as might be ab- solutely necessary, it was deemed expedient in constructing the bushel, to adhere as nearly as possible to the form of that known by the appellation of the Winchester bushel. It was therefore directed to be made cylindrical, the interior dia- meter being about i8|- inches, the exterior 19J inches, and the depth about 8^ inches, and intended to contain eighty pounds avoirdupois of distilled water. In order to give the bushel MDCCCXXVI. C 1 o Captain Kater's account of the additional strength, it was cast with two projecting hoops, one to which the bottom was screwed, and another at the distance of about half an inch from the top. Considerable difficulties arose in casting the bushel ; out of twelve, only five proved sound enough for use ; but by varying the process, they were at length procured sufficiently perfect. Much credit is due to Mr. Keir, the engineer em- ployed by Mr. Bate in turning the bushels, for the beauty and perfection of his work. The form of the gallon measure occupied much of my attention. It was necessary that it should be such as to enable me to determine the weight of distilled water it should contain with the least liability to error. The conical form was therefore adopted ; the mouth being made cylindrical, and one and a half inches diameter : the top was ground perfectly flat, and the edge so rounded off, that the contents might be poured from it into any other vessel without run- ning down the side. The cone was placed in a cylinder about four inches high, in which handles were formed, and which served at the same time to protect the gallon from injury, and to prevent any change of temperature which might arise from handling. The quart and the pint measures were of the same form on a smaller scale. The weights were of brass, and nearly of a spherical form, but flattened at the bottom. Into the top was screwed a button ; beneath which a small cavity was left to receive such' minute pieces of wire as might be found requisite to make up the standard weight. This button served also to lift the weight by means of a strong wooden fork. new standards of weights and measures. 1 1 The Imperial Troy pound is in the custody of G. Whittam, Esq. Clerk to the House of Commons, who obligingly per- mitted me to compare two weights with the standard at his house in Abingdon-street. These being intended merely as rough models for Mr. Bate to copy, it was not thought necessary to waste time in adjusting them with the utmost precision, and they were left a little in excess. The five Troy pounds being completed by Mr. Bate from the copy of the Imperial pound taken at Mr. Whittam's, I proceeded to compare them with the Imperial Troy pound, which was then confided to my care for that purpose. The balance employed in making the comparisons was made by Mr. Robinson, an artist who has directed much of his atten- tion, and with great success, to the improvement of this instrument. The beam is only ten inches long, and toge- ther with the scale pans weighs eight hundred grains. The scale pans are attached to agate planes, which rest upon knife edges. The ultimate angle of the central knife edge is 120 degrees. This balance, with one pound avoirdupois in each scale, it may be seen by the following details, varies immediately one division, equal to about one-tenth of an inch, on the addition of one-hundreth of a grain. Adjustment of the standard troy pounds. In order to distinguish the troy pound weights from each other, they were marked in the following manner : life Captain Kater's account of the That which I shall call |T^ P° No. 1. \ 1824 No. 2. all CY .1. (.1 CT I 1824* a dot after the figures. No. 3. I •'■ * *^ • * dot under the letter D. ( 1834 No. 4. < * . a dot under the letter D, and another ^- * * ^l824. dot after the figures. T. -r ( T y P ° a dot under the letter Y, another dot No. 5' \ ^QnA * under the letter D, and a third dot (lei 24. after the figures. The Imperial Standard troy pound was put into the scale, and counterpoised. The division and fraction of a division which would have been pointed out by the index, had the beam been allowed to come to a state of rest, was ascertained by taking the mean of the extremes of the vibrations, when their extent did not exceed one division. By this much time was saved, and it is presumed greater accuracy attained. The standard pound was then removed and replaced by the copy, and the point of rest determined as before : the dif- ference between these means converted into parts of a grain, gave the error of the copy. The same method was followed in the adjustment of all the weights. No. 1 . being too heavy, was laid aside for the present. No. 3. being too light for the limits of the index, was also set aside. By many careful trials, one-hundredth of a grain occasioned a variation in the index of 0,67 divisions. new standards of weights and measures. IS Standard Pound Divisions. No. 3. DiTisions. Error Divisions. Mean. Error ingrdns. + 0,5 + 1,0 + i>o — a,o -1.5 — 2.5 3 — 2,5 — >037 No. 4. + 1,4 + 0,1 + 0,3 + 0,4 + 0,9 + 0,0 + 0,4 + 0,3 —0.5 ") — 0,1 r + o,x ( —0,1 } — 0,15 — ,0022 No. 5. + 0,5 + 0,0 + 0,4 + 0,2 + 0,1 + o,i — 0,1 + 0,3 + 0,3 — 0,3 — 0,4 -N — 0,1 # — 0,1 V -0.5 I — o>4 J — 0,3 — ,0044 Wires of the following weights were now added : To No. 2. - - ,020 grains. 3. - - ,050 4. - - ,002 5. - - >oo4 The centre of gravity of the balance was raised, so that by frequent trials, one hundredth of a grain occasioned the index to vary one division. Standard Pound Divisions. No. 3. Divisions. Error Divisions. Mean. Error in grains. — o>5 — 0,6 — 0,2 + 0,1 — 0,2 — 0,5 — 0,1 + 0,3 — 0,6 + 0,1 — 2,1 — 2,1 + 0,4 -J + 0,9 -0,4 I + o>o ^ — 1,9 — 1,6 J — Oyf3- — ,0043 The centre of gravity was lowered, so that one-hundredth of a grain was equal to eight-tenths of a division. 14 Captain Kater's account of the Standard Pound Divisions. No. 3. Divisions. Error Divisions. Mean. Error in grains. — 0,5 0,0 — 0,3 — 0,3 — 0,8 — 0,9 — 0,8 — 0,7 -0,3 -) -0,9 1 -0,5 f -0,4 J — 0,52 — ,0065 No. 4. + 0,3 + 0,1 + 0,5 — o,x 0,0 — 0,1 + 0,3 + 0,1 — 0,2 0,0 — 0,4 — 0,1 0,0 ■" 0,0 — 0,7 + 0,1 — 0,4 0,0 - — 0,17 — ,0021 No. 5. — 0,1 + 0 + o,i + 0,2 + 0,2 + 0,3 — 0,2 — 0,2 0,0 + 0,2 + 0,2 — 0,2 — 0,1 — 0,1 - — 0,1 + 0,1 0,0 — o,i — 0,5 + 0*1 ^ ^ — 0,08 —,0010 The following quantities were added to the different weights : To No. 3. 4. 5. iQ05 grains. ,002 ,00a Mr. Robinson exchanged the balance I had hitherto used for another, which he thought superior. The mean of many trials gave 0,7 of a division for the variation occasioned by one-hundredth of a grain. new standards of weights and measures. 15 Standard Pound Dmsions. No. 2. Divisions. Error Division*. Mean. Error ingrains. 0,0 + 0,1 + 0,3 + 0,1 — 0,1 + 0,1 + 0,3 + a,4 + 0,2 + 0,3 + 0,2 + 0,4 + o»3 "^ + 0,3 — o,i + 0,2 + o>3 + 0,3 J »• + 0,2 + ,0029 No. 3. -0,4 -0,9 — 0,8 - '>S — 1,0 — i,o - 1,4 -2,3 -0,6 -^ — 0,1 1 -0,6 f -0,8 J — 0,52 - ,0074 No. 4. + 0,1 + 0,1 0,0 0,0 + 0,7 + 0,7 + 0,6 + 0,7 + o,s 0,0 + 0,1 + 0,8 + 1,0 + 0,8 + 0,8 + 1,2 + 0,4 ■" — 0,1 + 0,1 + 0,29 + ,0041 + 0,8 + 0,3 + 0,1 + 0,2 + o»5 . >■ No. 5. + 0,1 0,0 0,0 0,0 + 0,1 0,0 0,0 — 0,1 0,0 1 0,0 0,0 f — o,i J 0,0 0,0 By many careful trials previous to the following compa- risons, one-hundredth of a grain occasioned a variation of 0,9 of a division. Standard Pound No. 2. Enor Mean. Error Divisions. Divisions. Divisions. in grains. 0,0 + 0,1 + 0,1 -] 0,0 0,0 0,0 — 0,2 + 0,15 + o»i + 0,3 + 0,3 — 0,15 > + 0,16 + ,OOl8 — 0,05 + 0,35 + 0.4 , 0,0 + 0,3 + 0,3 J • ' i6 Captain Kater's account of the No. 1 . was reduced in weight, and being then too light, ,005 of a grain was enclosed in it and the following compa- risons made : Standard Pound Divisions. No.i. Divisions. Error Divisions. Mean. Error in grains. — 0,2 — 0,15 — 0,35 — 0,5 + 0,15 — 0,15 — o,3S — 0,50 — 0,20 + 0,70 — 0,10 + 0,05 ^ — 0,20 — 0,15 [ + 0,30 r 0,00 J + 0,09 + >OOI Added ,005 of a grain to No. 3. Standard Pound Divisions . No. 1. Divisions. Error Divisions. Mean. Error in grains. — 0,4 — 0,6 ~o,4 — 0,1 + 0,1 + 0,1 — 0,65 — 0,50 — 0,40 — 0,20 + 0,20 + 0,20 — 0,25 - + 0,10 0,0 — 0,10 + 0,10 + 0,10 ^ > 0,0 ,00 No. 3. \ + 0,1 0,0 0,0 — 0,1 — o>i 0,0 + 0,15 0,0 0,0 0,0 — 0,2 + 0,2 + 0,05 -\ 0,0 0,0 . + 0,1 c — o,i + Oj2 + 0,04 + ,0005 The wires which were found necessary to make each of the copies equal to the Standard troy pound being enclosed, the button was screwed in with a force sufficient to resist any ordinary attempt to detach it ; but should such an en- deavour ever be made with success and the wires be lost, the following table contains an account of their number and value. new standards of weights and measures. 1 7 No. 1 . contains 1 wire = ,005 gr. 2. . . 1 wire =: ,020 gr. 3. . . 3 wires = ,050 + ,005 + ,005 gr. 4. . . 2 wires = ,002 + ,002 gr. 5. . . 2 wires = ,004 + ,002 gr. In order to employ the whole of the preceding comparisons in deducing a final result, it will be necessary to add to each error given in the Tables the sum of the weights which were enclosed after the determination of such error. Troy Pound No, 1. The mean of six comparisons gave for the error of No. 1 . The mean of six other comparisons Troy Pound No. 2. The mean of three comparisons gave for the error of No. 2. — ,037 + ,02 = The mean of six other comparisons of six other comparisons Troy Pound No. 3. The mean of six comparisons gave ,0043 + ,005 + ,005 =: - The mean of four other comparisons gave — ,0065 + ,005 + ,005 = - The mean of four other comparisons gave — ,0074 + ,005 - - ' = - The mean of six other comparisons - - MDCCCXXVI. D Grains. +,001 - ,000 — ,0170 + ,0029 + ,0018 + ,0057 + ,0035 ^ ,0024 + ,0005 18 Captain Kater's account of the Troy Pound No. 4. The mean of four comparisons gave — ,0022 -f- ,004 = - - - The mean of six other comparisons gave — ,0021 + ,002 := - - « The mean of eight other comparisons Grains. + ,0018 — ,0001 + ,0041 Troy Pound No. 5. The mean of five comparisons gave — ,0044 + ,006 =----}- ,0016 The mean of seven other comparisons gave — ,001 + ,002 = - _ - + ,0Q10 The mean of four other comparisons - - ,0000 In order to deduce a final mean from these results, each result was multiplied by the corresponding number of com- parisons, and the sum of the products thus obtained vv^as divided by the sum of the comparisons. In this manner the following errors of each of the troy pounds was determined. Grains. No. 1. - - + ,0005 2* - - — ,0015 3. - - + ,0021 4. - - + ,0022 5. - - + ,0010 These errors being so small and mostly in excess, it was not thought necessary to make any attempt to correct them. The five troy pounds previous to their being delivered to new standards of weights and measures. ip me had been adjusted by Mr. Bate, and with the exception of an excess of one hundredth of a grain common to all, and which appears to have been the error of the copy taken at Mr. Whittam's, the greatest difference from the preced- ing results did not exceed four or five-thousandths of a grain. The adjustment of the five troy pounds occupied me from the commencement till the middle of March 1825, during which time Mr. Bate was engaged in preparing a balance sufficiently strong to be used in determining the gallon weights ; this balance was brought to my house on the 16th of March. I shall now proceed to describe the manner in which the avoirdupois pound was derived from the troy pound. For this purpose Mr. Bate made the following weights : 1 of 5760 grains. '^ 2 — 2880 3 — 960 2 — 480 2 — 240 5 — 48 2—24 2 — 12 2—6 2 — 3 3 — 1 In all twenty-six weights. Of the above weights the following were used to make up an avoirdupois pound : ao Captain Kater's account of the 5760 960 240 24 13 3 1 7000 grains. In this manner five avoirdupois pounds were made and adjusted by Mr. Bate. Determination of the Avoirdupois Pound. Wishing to avoid the verification of the numerous weights used by Mr. Bate, and desirous of arriving at my object by a road different from that which he had pursued, I used the following method : I caused Mr. Bate to make two weights each equal to six troy pounds. These I compared with the Imperial Standard Troy pound, and the five troy pounds already adjusted. I had thus two known weights each equal or nearly so to six troy pounds, one of which with the addition of 440 grains gave me a weight equal to five avoirdupois pounds, subject only to such error as might arise from inaccuracy in the grains, and as I had had sufficient proof of Mr. Bate's care, I had little to apprehend on this point. The five avoirdupois pounds were then compared with each of the six pound weights and 440 grains, and the mean new standards of weights and measures. 21 taken, and thus the sum of the errors of the five avoirdupois pounds became known. Assuming one of these pounds (No. 1. ) as a standard, each of the others was then compared with it, and their relative errors thus ascertained, from which, and the sum of the errors of the five avoirdupois pounds, the error of each was deduced. The following is a detail of the comparisons. The variation of the index was carefully ascertained to be one division for one-tenth of a grain. The sixTroy Pounds, Divisions. The 6 lb. weight. No. 1. Divisions. Difference Divisions. Mean. Difference ingrains. — 0,4 + 1,1 + i,o — 1,9 — 2,0 — i,o — 4,0 -5,0 — 2,9 0,29 Added three-tenths of a grain to the 6 lb. weight No. i . 1,8 2,9 S'7 3>4 2>5 •0.5 ■4,8 3>8 2,3 2,7 2,6 + 1^3 — 1,9 + 1,9 — 0,6 + 0.7 — o,i J r T ' x'i + 0,2 + 0,02 By several trials one-tenth of a grain occasioned a varia- tion in the index of 0,7 of a division. Captain Kater's account of the The sixTroy Pounds, DiTisioas. Ui 0,0 — 1,0 — 2,2 The 6 lb. weight, No. 3. Divisions. •2,0 ■4.8 3'6 Difference Divisions. 2,0 3.8 1,6 1.4 } Mean. 2,2 Difference in grains. — 0,31 Added two-tenths of a grain to the 61b. weight No. 2. + 1.5 + 1,2 + 1.7 -3.8 -3.8 — 4.8 — 0,2 _-5?2*4 — 2,3 — 1,9 — 3.3 ~o,5 — 1.5 + 1,2 -1,8 — 7.0 — 4,6 — 4'8 -3,6 -3.6 — 4>6 -4.3 — 2,0 — 2,7 — 0,5 + 20 — 3.2 + 0,2 — 4,6 — i»% — I, -'2,7 — 1,0 — ».54 — 0,22 Added 0,17 of a grain. The 6 lb. weight No. 1. The mean of four comparisons gave for the difference of No. 1. from the six troy pounds, — ,29 + ,3 = +,01 The mean of six other comparisons - - +,02 The 6 lb. weight No. 2. The mean of four comparisons gave for the difference of No. 2. from the six troy pounds --,31 + ,2 -f->i7= +,0^ The mean of 1 1 other comparisons gave — ,22 +,17 = —,05 The final means of these results obtained in the same manner as those of the troy pounds are as follows : Grains. The difference of No. 1, from the six troy pounds is +,016 of No. 2, _ _ _ - — ,020 The mean difference is — ,002 new standards of weights and measures. ' 23 The avoirdupois pounds were distinguished from each other by the following marks. That which I shall call C 1 P" Av'' No. 1. 1 1824 No. 2. -J ' 1824 • a dot after the figures. -T ( 1 P° Av* a dot under the letter S, and another i 1824* °°* ^^^ ^"® figures. No. 4. No. 5. 1 P^ Av* a dot under the letter D, another dot under the letter S, and a third dot 8 24 • after the figures. {': These weights were successively compared with the avoir- dupois pound No. 1 . which was taken both before and after the others ; for this purpose Mr. Robinson's balance was used. One hundredth of a grain occasioned a variation of 0,7 of a division. I Avoirdupois Pounds. No. I. Divisions. No. 2. Divisions. No. 3. Divisions. No. 4. Divisions. No. 5. Divisions. No. I. Divisions. + 0,2 — 0,4 — 0,4 — 0,5 — 0,4 — 0,4 — 0,3 0 A — 0,4 — 0,4 — 0,4 0 1 — 0,8 — 0,7 — 0,7 — 0,9 . — 0,8 — 0,8 -0,7 + 0,3 — 0,2 — 0,5 — 0,2 Wjjj. *-'»j "»7 — 0,28 — 0,15 — 0,37 Mean. — 0,37 — 0,72 — 0,8 — 0,15 — 0,21 Means. By the above comparisons the difference of each weight from No. 1. is as follows; 24 'Captain Kater's account of the No. 2. 3. 4. 5. u^nit*- ,i6 divisions = — ,002 grains. . — ,16 . . = — ,002 . — ,51 . . = —,007 • — ,59 . . = — ,008 Sum of the differences — ,019 I now proceeded to compare the five avoirdupois pounds with each of the 6lb. weights, to which 440 grains, taken from Mr. Bate's weights, were added, and which together made five pounds avoirdupois. One tenth of a grain occasioned the index to vary one division. The 6 lb. weight N0.I. + 440 gr. Divis. The five Avoirdupois Pounds, Divisions. Difference Divisions. Mean. Difference in grains. — 1,0 — 0,8 + 0,6 + 1,8 + 1^7 + 1^5 0,0 + 2,7 -1,9 — 2,2 — 3^9 —0,5 + 2,2 + 1>I + 0,1 + I>I — 0,4 — o>7 — 2,9 — 1,4 — 2,9 + 0,3 + 1,6 — 0,7 — 1,6 — 0,4 — 0,4 — 2,0 1 .0 '- — 0,63 — 0,063 + 0,8 ^ The 6 lb. weight No. 2. + 440 gr. Divis. The five Avoirdupois Pounds, Divisions. Difference Divisions. Mean. DiflFerence in grains. — 1,0 3>o — 1,6 — 1,2 — 0,9 — 2,1 -1,6 — 0,4 — 0,2 — 0^7 — 1»3 — 0,7 — 2,1 1,2 — 0,8 — 0,7 — 1,2 — 1,0 — 0,7 — 0,4 — 0,3 "] + 2,3 — 0,5 0,0 + 0,1 + 1,4 + 0,4 — 0,6 — 0,5 + 0*3 J > + 0,26 + 0,026 new standards of weights and measures. 25 Deductions from the preceding comparisons. 3 .'iAvl The mean of the differences of the two 6 lb. weights from the six troy pounds is - - - — ,0020 grs. But the sum of the errors of the six troy pounds is ----- + ,0039 Therefore the mean of the errors of the two 6 lb. weights is - - - + >ooi9 The first comparisons of the five avoirdupois pounds with one of the 6 lb. weights + 440 grains gave for the difference - . - - - - — ,o6so grs. With the other 6 lb. weight + 440 grains, the difference was - - - + ,0260 The mean is - - — ,0185 But the mean error of the two 6 lb. weights is +,0019 Therefore the sum of the errors of the five avoirdupois pounds is ^ ^ - — ,0166 The sum of the differences between No. 1. and the other avoirdupois pounds being ,019 grains, and all in defect, wires of the following values were enclosed in each weight ; viz. In No. 2. - - ,002 grs. * 3. - - ,002 4. - - ,006 5. - - ,007 Total - ,017 MDCCCXXVI. E / fS .Yw Captain KaTEr's account of the The very near agreement of the preceding result with Mr. Bate's determination, is a sufficient proof of his care, and. of the accuracy with which the avoirdupois pound has been obtained. As each of the avoirdupois pounds had certain wires enclosed in it when delivered to me by Mr Bate, the folio w- ingis, an account of the wires they now contain. No. 1. contains i wire = ,053 grains. 2. — 4 wires = ,184 3. — 4 wires = ,200 ^ 4. — Swires = ,250 .ei2 be/do 5. _ not noted. After the adjustment of the avoirdupois pounds was com- pleted, Mr. Bate used the large balance to make an approxi- mate adjustment of the weights of the imperial gallon of distilled water. This was interrupted by an accident which rendered it necessary to repair the knife edges of the beam ; and notwithstanding every care, the balance afterwards proved less certain in its indications than it was before the accident. The error arising from this source I have endea- voured to lessen by increasing the number of comparisons. Adjustment of the weights of the imperial gallon of water. These weights were distinguished in the following manner : new standards of weights and measures. That which I shall calif ^^ ^^ No.i.j. «7 IMP. GALL. OF WATER AT 62° F VO: COF ). 3. \ >. 4. \ wt of IMP. GALL. " ^'^"' WATER AT 62° F. a dot after the letter F. Wt of IMP. GALL. \ ; OF WATER AT 62S. J a dot after the figures. Wt of IMP. GALL. p,i + i OF WATER AT 62? F. a dot after the figures, and another dot after the letter F. The two 6 lb. troy weights with 880 grains, making toge- ther ten pounds avoirdupois, were employed as a standard in the manner which has been already detailed in describing the adjustment of the troy pounds. ^^ From previous rough trials, certain wires were added to each of the gallon weights, the value of which will be given hereafter, and the following comparisons were made. The index of the balance varied one division with one-tenth of a grain. _ The two 6 lb. weights + 880 grains. Divisions. Gallon weights. ■ 1 The two 6 lb. weights + 880 grains. No. I. Divisions. No. 2. Divisions. No. 3. Divisions. No. 4. Divisions. + 2,5 + 5,8 -0,6 -0,8 — 0,1 — 3,c — 3,2 + 3,9 -6,4 -2,8 — 2,0 + 2,5 + 2,7 — 3-3 — 4,1 — 0,2 — 3,3 + 0,8 -1,5 — 1-7 — 0,9 + 1.5 -4,9 4-5,4 + 2,1 — 2,t -8,1 + 1,2 -4,1 + 6,8 + 4,S — 1,7 + ©,4 — 2,5 — 2,2 + 0,63 + 0,85 — 1,98 — 0,95 — 1,12 — 0,93 + Q,»5 + 0,74 Mean. ?8 Captain Kater's account of the By the above comparisons, the error of each weight in parts of a grain is as follows : No. 1. No. 2. No. 3. No. 4. — ,272 — ,169 — ,186 — ,167 The two 6 lb. weights + 880 grains. Divisions. Gallon weights. The two 6 lb. weights + 880 grains Divisions. No. 1. Divisions. No. 2. Divisions. No. 3. Divisions. No. 4. Divisions. — 1,9 + 3>o + 2,9 + 4,2 + 1,4 + 2,5 + i>3 + 3>o -1,9 — 1,0 + 0,8 + 2,9 0,0 + 1,2 + 2,0 + +0 — 2,0 -4,9 + 0,6 — >.7 + 0,2 + 1,6 + 3.1 — 3'2 — 0,6 — 3,3 — 1,9 + o>S — 1,8 tl% + 0,3 — 1,9 + 1,0 + 3'3 + ».9 -\-Z>9 + 4,8 + 4,7 — 1,0 + »,7 + 3>4 + 3.3 + 2,8 + 4.1 + 0,5 + 5,2 + 3.4 + 2,05 + 3.0S + 1,00 — 0,79 — 1,61 + 2,09 + 3>o5 + 2,55 Mean. By the above comparisons, the error of each weight in parts of a grain, is as follows : No. 1. No. 2. No. s. No. 4. — ,155 — ,334 — ,416 — ,046 The two 61b. weights + 880 grains. Divisions. Gallon weights. The two 6 lb. weights + 880 grains. Divisions. No. I. Divisions. No. 2. Divisions. No. 3. Divisions. No.v Divisions. + 4>o + 3.5 -5,0 -1,9 + 2,9 + 3>7 + 1,2 + 3,0 — 1,7 — 0,8 — 4.9 + 2,2 + 3,1 _o,4 — 2,6 — 1,6 + 1,2 + 2,5 — 1,5 — 3,0 — 3.4 — 0,4 . — 3»9 + 6,2 — i,o — 3.8 + 0,1 + 1,1 + 1.3 + 7,2 — 0,2 — 0,5 + 2,7 + 1,6 + 3,0 + 1,20 + 2,30 — 0,17 — 0,27 — 1,61 + 0,65 + 2,30 + «»75 Mean. new standards of weights and measures. m^ By the above comparisons the error of each weight in parts of a grain is as follows : No. 1. No. 2. No. 3. No. 4. — ,192 — ,202 — ,336 — ,110 Results of the comparisons of the four weights of the imperial gallon of water. No. 1. No. 2. No. 3. No. 4. Grains. Grains. Grains. Grains. 1st series . . — ,272 — ,169 — ,186 — ,167 2nd series . . — ,155 — ,334 — ,416 — ,046 3d series . . — ,192 —,202 — ,SSQ — ,110 Mean errors . — ,206 — ,235 — ,313 — ,108 A wire equal to its error was now enclosed in each weight. The numbers and values of the wires inclosed in the gallon weights are as follow : Grains. No. 1 . contains 2 wires, together = 0,366 No. 2. — 4 wires, — = 1,174 No. 3. — 3 wires, — = 0,791 No. 4. — 3 wires, — = 0,422 The adjustment of the gallon weights occupied me till the 10th of April, when the balance was removed to Mr. Bate's for the purpose of adjusting the standard gallon measures. Adjustment of the imperial gallon measures. It has been remarked that the form chosen for the gallon measure is that of a hollow cone, terminated by a cylindrical mouth of about an inch and a half diameter. The inside of . go Captain Kater's account of the the cone is turned very smooth and close to its base is curved so as to avoid the acute angle, which would have resulted from continuing the side of the cone to the bottom. By this also the advantage was gained of a greater substance for the insertion of the screws used for attaching the bottom of the gallon to the cone. As soldering was thought objectionable, the bottom was ground to the cone, and it was supposed that it would thus have been sufficiently secure ; but on letting the gallons remain filled for 24 hours, in some a slight leakage became perceptible. After many experiments, the best remedy for this appeared to be a very minute quantity of fresh grease, carefully applied to the bottom of the cone and then almost wholly wiped off; after which the bottom was firmly screwed in its place. The following was the method pursued in adjusting the gallon : If the gallon contained a considerable quantity, as one or two hundred grains of water too little, its capacity was enlarged by turning away a small portion from the flat bottom. If on the contrary the gallon contained too much, the base of the cone was ground away ; and it must be evi- dent that a very small quantity taken from this part would occasion a considerable variation in the capacity, one thou- sandth of an inch making a difference of about 17 grains. Errors of smaller magnitude were removed either by grind- ing down the top of the mouth, or by enlarging the aperture by using a cylindrical plug of brass with emery. The interior of the measure being carefully wiped dry, it was placed in the scale together with one of the gallon new standards of weights and measures, si weights and a circular piece of plate glass ( the use of which will be presently described), and the whole was counter- poised, .jj-j^, . The division at which the index of the balance stood was noted, and the gallon weight removed ; the gallon was then nearly filled with distilled water by means of a small glass syphon, so contrived by Mr. Bate as to prevent the intro- duction of bubbles of air. The temperature of the water was then taken as well as the height of the barometer, and the filling of the gallon continued until the water rose percepti- bly a little above its mouth. The piece of plate glass before- mentioned, and which had a small hole drilled in its centre, was then carefully placed upon the top of the gallon, when the superabundant water passed through the hole to the upper surface of the glass, and was removed by drawing it with the mouth into a capillary glass tube. The difference of the expansion of water, and of brass, being an object of the highest importance in the present operations, I was glad to find that Mr. Bate had made nume- rous experiments upon this subject, and I had had sufficient experience of his care to place great reliance upon his con- clusions. It will be seen that the considerable range of tem- perature under which the experiments with the gallons No. 1, 3, and 4, were made, and the uniformity of the results fully justify this confidence, and form very conclusive evi- dence of the accuracy of the corrections employed. But besides the correction for the difference of the expan- sion of water and of the brass vessel, another allowance is necessary for the buoyancy of the atmosphere in cases where extreme accuracy is required. The gallon is to contain ten 32 Captain Kater's account of the pounds of distilled water, at the temperature of 62° of Fa- renheit's thermometer, the barometer being at 30 inches ; consequently, for any difference from this state of the baro- meter, as well as of the thermometer, a correction must be applied. Water is 831 times heavier than air when the barometer is at 30 inches, and the thermometer at 62°, and this varies directly as the height of the barometer, consequently the correction due to a difference of one inch of the barometer will be -5 — X — = -^— part of the weight of water. 831 30 24930 r & The gallon weight being counterpoised with brass, and brass being about 8 times heavier than water, the effect of the buoyancy of the atmosphere upon brass will be only ^ of that upon water, and this will tend to lessen the effect upon the water by one eighth part of the whole quantity. Therefore — -— ^ I x 70000 grains = 2,46 grains, is the number of grains by which the weight of the gallon of water will be increased by a depression of one inch of the barometer. Though the variation of the temperature of the air during the experiments was several degrees, the effect upon the correction for the buoyancy of the atmosphere would have been so inconsiderable as to be unworthy of notice upon the present occasion. As an error of one degree in the determination of the temperature of the water contained by the gallon would occasion an error ranging from four to six grains, it must be evident that a knowledge of the precise temperature of the Wjater was of primary importance. For this purpose a thermo- meter was used which had been prepared with extraordinary care by Mr. Bate, and the scale was such that its indications were estimated without difficulty to tenths of a degree. new standards of weights and measures. 33 It would perhaps be useless to detail the numerous expe- riments which were made in approximating to the final adjustment of the gallon measures, and I shall therefore immediately proceed to state the ultimate results. Gallon (which I shall designate) No. 1. Date. Barom. Temp, of the Water. Weight of water con- tained bythe gallon, lolbs. ± Correction for Barometer. Correction for Temperat. Weight of water the gallon should have contained. 10 lbs. ± Error ingrains. June. I 6 II «5 Inches. 30,29 29,94 30,22 30,16 30,27 0 59>o 59,4 66,6 67,8 67,2 Grains. + 13,13 + 11,14 — 24,96 — 30,84 — 27,21 Grains. — 0,71 + 0,15 — 0,54 — 0,40 — 0,66 Grains. + 12,38 + 10,83 — 23,29 — 30,17 — 26,68 Grains. + 11,67 + 10,98 — 23,83 — 30,57 — 27,34 + 1,46 + 0,16 — 1,13 — 0,27 + 0,13 Mr. Bate. Mr. Bate. Mr. Bate. Mean -1-0,07 The bottom of the gallon No. 2. was rather thin, it was therefore subsequently adjusted by Mr. Bate, and sentto'the Exchequer to be used on more ordinary occasions. Gallon No. 3. Weight of Temp. Weight of water con- Correction Correction water the Error Date. Barom. of the Water. tained bythe gallon. 10 lbs. ± for Barometer. „ ^°^ ^ should have Temperat. contained. 10 lbs. ± m grains. May. Inches. 0 Grains. Grains. Grains. 1 Grains. 18 30,33 57.9 + 16,52 — 0,81 + 16,34 + 15,53 + 0,99 20 30,29 57.4 + 18,48 — 0,71 + 18,02 + 17,31 + 1,17 23 29,96 60,5 + 6,67 + 0,10 + 6,44 + 6,54 + 0,13 31 30,30 59.0 + 12,58 — 0,74 + 12,38 + 11,64 + 0,94 Mr. Bate. June 30,30 59,2 + 9,78 — 0,74 + 11,60 j+ 10,86 — 1.08 Mr. Bate. I 30,30 58,8 + 12,72 — 0,74 -f- 13,10 ;-|- 12,36 + 0,36 II 30,18 67.3 — 31.53 — 0,45 - 27,26 — 27,71 - 3,82 Mr. Bate. >3 30,14 67,4 — 26,74 — 0,35 ~ 27,84 — 28,19 + 1.45 30,14 68,2 — 31,80 — 0,35 - 32.54 — 32.89 + 1.09 Mean + 0,14 MDCCCXXVI. 34 Captain Kater*s account of the Gallon No. 4. Date, Barom. Temp, of the Water. Weight of water con- tained bythe gallon, lolbs. Correction for Barometer. Correction for Temperat. Weight of water the gallon should have contained 10 lbs. d Error in grains. June. 6 8 II 13 H Inches. 29,94 29'95 30,22 30,16 30,14 30,28 30,25 59*2 61,7 66,9 68,2 67,0 68,8 67*9 Grains. + 12,36 + 2,36 ^ 19,69 — 28,58 — 25,30 — 36,42 30>84 Grains. + 0,15 + 0,12 — o>54 — 0,40 — 0,35 — 0,69 — 0,61 Grains. -\- 11,60 + 1,31 - 24,96 - 32,54 - 25,52 - 36,17 - 30.75 Grains. + »i.75 + 1,43 — 25,50 — 32,94 — 25,87 — 36,86 -- 31,36 + 0,61 + Q>93 + 5.81 + 4,36 + 0,57 + 0,44 + 0,52 Mr. Bate. Mr. Bate. Mr. Bate. Mean Mean, rejecting greatest and least + 1,89 + 0,61 Gallon No. 5. Date. Barom. Temp, of the Water. Weight of water con- tained bythc gallon. iolbs.+ Correction for Barom^er. Correction for Tempeiat. Weight of water the gallon should have contained. lolbs. + Error in grains. ■ June. 1 3 8 Inches. 30,30 30,27 29,70 29,95 0 58.7 60,25 60,6 61,4 Grains. + 12,83 + 5>8o + 7.9' + 2,80 Grains. — 0,74 — 0,66 + 0,74 + 0,12 Grains. + 13,47 + 7,47 -1- 6,02 H- 2,63 Grains. + 12,73 + 6,81 + 6,76 + 2,75 + 0,10 — 1,01 + i»i5 + 0,05 Mr. Bate. Mean + 0,07 Adjustment of the Qiiart and Pint for the Exchequer. The quart and pint measures for the Exchequer differed in no respect from the gallon, except in being of inferior dimensions, and were adjusted in a similar manner. new standards of weights and measures* . 55 Quart. Date. Barom. Temp, of the Water. Weight of water con- tained bythe quart. 2I lbs. ± Correction for Barometer. Correction for Temperat. Weight of water the Quart should have contained. z\ lbs. ± Error in grains. June. J5 Inches. 30,27 30,27 30,27 0 69,0 67,1 67,5 68,1 Grains. — 9'82 — 6,98 — 6,86 — 8,12 Grains. — 0,16 — 0,16 — 0,16 — 0,16 Grains. — 9'34 — 6,52 — 7." — 7,98 Grains. — 9,50 — 6,68 — 8,14 — 0,32 — 0,30 + 0,41 + 0,02 Mean — 0,05 Pint. Date. Barom. Temp. of the Water. Weight of water contained by the pint. 1 4 lbs. ± Correction for Barometer. Correction for Temperat. Weight of water the pint should have con- tained. li lbs. ± Error in grains. June. 18 Inches. 30,27 30,18 30,18 67,6 63,0 63,4 Grains. — 3,63 — 0,53 — 0,70 Grains. — 0,08 ^ 0,05 — 0,05 Grains. — 3,55 — 0,58 — 0,82 Grains. — 3'63 — 0,63 — 0,87 0,00 + 0,10 + 0,17 ^ Mean + 0,09 Verification of the Bushel measures. The weight of the bushel measure, together with the 80 lbs. of water it should contain, was about 250 lbs. and as I could find no balance capable of determining so large a weight with sufficient accuracy, I was under the necessity of constructing one for this express purpose. 36 Captain Kater*s account of the I first tried cast iron ; but though the beam was made as light as was consistent with the requisite degree of strength, the inertia of such a mass appeared to be so considerable, that much time must have been lost before the balance would have answered to the small differences I wished to ascertain. Lightness was a property essentially necessary, and bulk was very desirable in order to preclude such errors as might arise from the beam being partially affected by sudden alte- rations of temperature. I therefore determined to employ wood, a material in which the requisites I sought were com- bined. The beam was made of a plank of mahogany about 70 inches long, 22 inches wide, and 2^ thick, tapering from the middle to the extremities. An opening was cut in the centre, and strong blocks screwed to each side of the plank to form a bearing for the back of a knife edge which passed through the centre. Blocks were also screwed to each side at the extremities of the beam on which rested the backs of the knife edges for supporting the pans. The opening in the centre was made sufficiently large to admit the support hereafter to be described, upon which the knife edge rested. In all beams which I have seen, with the exception of those made by Mr. Robinson, the whole weight is sustained by short portions at the extremities of the knife edge, and the weight being thus thrown upon a few points, the knife edge becomes more liable to change its figure and to suffer injury. To remedy this defect, the central knife edge of the beam I am describing was made six inches, and the two others five inches long. They were triangular prisms with equal sides, of three quarters of an inch, very carefully finished, and the edges ultimately formed to an angle of 120°. new standards of weights and measures, si Each knife edge was screwed to a thick plate of brass, the surfaces in contact having been previously ground together, and these plates were screwed to the beam, the knife edges being placed in the same plane, and as nearly equidistant and parallel to each other as could be done by construction. The support upon which the central knife edge rested throughout its whole length was formed of a plate of polished hard steel screwed to a block of cast iron. This block was passed through the opening before-mentioned in the centre of the beam and properly attached to a frame of cast iron. The stirrups to which the scales were hooked rested upon plates of polished steel to which they were attached, and the under surfaces of which were formed by careful grinding into cylindrical segments. These were in contact with the knife edges their whole length, and were known to be in their proper position by the correspondence of their extremi- ties with those of the knife edges. .A well-imagined contrivance was applied by Mr. Bate for raising the beam when loaded, in order to prevent unneces- sary wear of the knife edge ; and for the purpose of adjusting the place of the centre of gravity, when the beam was loaded with the weight required to be determined, a screw carrying a moveable ball projected vertically from the middle of the beam. The performance of this balance fully equalled my expec- tations. With two hundred and fifty pounds in each scale, the addition of a single grain occasioned an immediate varia- tion in the index of one-twentieth of an inch, the radius being fifty inches. In using this beam, care should be taken that the ends of 38 Captaifi Kater's account of the the steel plates to which the stirrups are attached coincide with the ends of the knife edges, otherwise some error might arise from a possible want of parallelism. The bushel measure being placed in one of the scales, together with 80 lbs. * the whole was counterpoised with brass ; the 80 lbs. was then removed, and the bushel filled with water by means of a syphon. The temperature of the water was then very carefully taken, and the height of the barometer registered. A circular piece of plate glass, as plane as could be procured, having a hole about a quarter of an inch diameter in its centre, was slid over the bushel, and the air-bubbles which appeared on the under surface of the glass were removed by touching them with a^ small bent tube made of flexible metal, a method thought of by Mr. Bate. Water was added through the hole in the glass ; and by carefully observing the curvature of the fluid surface, it was soon evident that the filling of the bushel might be repeated without a greater difference than three or four grains. It is scarcely requisite to remark that many experiments were made, not here detailed, before the adjustment of the bushel was perfected ; the very great accuracy and masterly workmanship however of Mr. Keir, who had been furnished with gauges for the diameter and depth of the bushel, ren- dered little alteration necessary. * This was obtained by taking twice the weight of the four weights of the gallon of water. new standards of weights and measures. Bushel No. i. 3^ Date. Barom. Temp, of the Water. Weight of water con- tained by the bushel, 80 lbs. ± Correction for Barometer. Correction for Temperat. Weight of water the bushel should have contained. 80 lbs. ± Error ingrains. June. 22 24 Inches. 30,00 29,98 29,96 60,30 61, 4 6i,75 Grains. + 61,10 + 34,40 + i2»5S Grains. O, O + 0,40 + 0,10 Grains. + 58,13 + 21,01 + 8»75 Grains. + 58,13 + 21,41 + 8,85 + 2,97 + 12,99 + 3»7o Mr. Bate, Mean + 6,55 Bushel No. 2. Date. Barom. Temp, of the Water. Weight of water con- tained by the bushel. 80 lbs. ± Correction for Barometer. Correction for Temperat. Weight of water the bushel should have contained. 80 lbs. ± Error in grains. July. 7 8 Inches. 30,00 29,98 29,98 0 63,1 62,5 62,6 Grains. — 38,00 — 18,10 — 19,59 Grains. 0,00 + 0,40 + 0,40 Grains. — 41,00 — 18,49 — 22,19 Grains. — 41,00 — 18,09 — 21,79 + 3,00 — 0,01 + 2,20 Mean + 1,73 Bushel No. 3. Date. Barom. Temp, of the Water. Weight of water con- tained by the bushel. 80 lbs. ± Correction for Barometer. Correction for Temperat. Weight of water the bushel should have contained. 80 lbs. ± Error ingrains. May. 18 20 24 31 J|»ne, »7 Inches. 30,33 30,29 29,83 30,28 30,16 0 57»4 62,3 59*3 66,8 Grains. + 141,65 + 140,54 + »»54 + 96,20 — 201,50 Grains. — 6,48 — 5.68 + 3*36 — 5>52 — 3,20 Grains. + I44>l6 + 1 36,06 — 11,09 + 89,73 ~'95>25 Grains. + i37>68 + 130,38 — 7.73 + 84,21 — 198,45 + 3.97 + 10,16 + 9,27 + 1 1,99 — 3,05 Mr. Bate. Mr. Bate. Mr. Bate. Mean + 6,47 40 Captain Kater's account of the Bushel No. 4. Date. Barom. Temp, of the Water. Weight of water con- tained by the bushel. 80 lbs. ± Correction for Barometer. Correction for Temperat. Weight of water the bushel should have contained. 80 lbs. ± Error in grains. June. 27 Inches. 29,77 29^77 29,79 0 6i,9 62,0 61,9 Grains. + 6,10 + 5>6o + 5»2o Grains. + 4.48 + 4*48 + 4.16 Grains. + 3,50 0,0 + 3>5o Grains. + 7.98 + 4,48 + 7>66 -1,88 + 1,12 — 2,46 Mean — 1,07 In order to enable the reader to form some idea of the errors of the measures of capacity, it may be remarked that a drop of water is commonly estimated to be nearly equal to one grain. As the quantity of water contained by the bushel measure is determined by the surface of the glass plate, which should be a perfect plane, a figure not easily attainable, it is not to be understood that the capacity of the bushel is true within the limits of the errors above-mentioned, but to the gallon, quart, and pint measures, in consequence of their more ad- vantageous form, this source of error does not in any sensible degree apply. Verification of the standard yards with steel terminations. These standard yards were made by Mr. Dollond ; they are of brass, one inch square. To their extremities are firmly screwed rectangular pieces of steel of the same width as the bar, and projecting above its surface. The distance between the interior faces of the steel termination is intended to be equal to the length of the imperial standard yard. new standards of weights and measures. 41 To determine this distance I employed the following method : Two bars of brass were prepared, three quarters of an inch square and rather less than 18 inches long. They were ter- minated by planes at right angles to their length ; and upon the upper face of each bar, very near to the end, a fine trans- verse line was drawn ; the other ends of the bars being then placed in contact and kept so by springs, the distance between the lines was taken by means of two micrometer microscopes fixed to a bar of wood and referred to Sir G. Shuckburgh's standard scale, which scale, it has already been remarked, does not sensibly differ from the imperial standard yard. The distance between the lines was found by numerous comparisons to be 919 divisions of the micrometer less than the standard yard, each division of the micrometer being equal to — ^ of an inch. ^ 23363 The brass bars were then placed upon the standard to be examined, their marked ends being next each other, and their opposite extremities kept in contact with the steel faces by a spring introduced between the bars, a part below the surface being cut away for that purpose. The distance between the lines was then measured by the micrometer microscope, which distance, had the standard been perfectly correct, would have been equal to what the distance of the lines in the former position of the bars wanted of s^ inches. Standard Yard, No. 1. The distance between the lines upon the brass bars was found by the mean of six measurements to be 918,2 divisions Df the micrometer, which differs so little from 919 divisions, MDCCCXXVI. G 4# Captain Kater's account of the that this standard yard may be considered as perfectly correct. Standard Yard, No. 2. The mean of sixteen measurements gave the distance between the lines upon the brass bars 910 divisions. This standard is therefore 9 divisions, or ,00038 of an inch too shortw Standard Yard, No. 3. By the mean of six measurements this standard appeared to be five divisions, or ,00021 of an inch too long. Standard Yard, No. 4. The mean of ten measurements gave the error of this standard five divisions, or ,00021 of an inch too short. Adjustment of the Standard Tards with gold points. The standard yards last described are intended merely for the purpose of sizing those employed in commerce, and the trifling differences above stated may be utterly disregarded ; but the Commissioners of Weights and Measures thought it desirable that accurate copies of the imperial standard yard should be made, to be carefully preserved and transmitted to posterity solely for the purpose of being referred to upon extraordinary occasions, or upon questions important to science. The difficulty of transferring a given distance from one scale to another, is well known to all who are acquainted with the subject ; the operation is one of considerable deli- cacy ; and notwithstanding every precaution, is seldom abso- nezv standards of weights and measures, 43 lutely free from error. But a national standard should be accurately that which it professes to be. It is not enough to determine its error, as the record of this may in process of time be lost ; it therefore became necessary to devise a method by which any perceptible error in those standards which are the foundation of all the others, might ultimately be annihilated. The four standard yards which I am about to describe are of brass, one inch and a quarter wide, and half an inch thick. This thickness is the same as that of Sir G. Shuckburgh's scale, and was chosen in order that both might be affected with equal readiness by any change of temperature ; for as the imperial standard yard of 1760 is one inch square, I thought it preferable to adjust the new standards by means of Sir G. Shuckburgh's scale, which, as I have before re- marked, does not sensibly differ from it. A disk of gold being let into the surface near one extre- mity, a hole was drilled through the bar at the distance of thirty-six inches from the centre of the disk, and being made slightly conical, a plug of brass was ground in the hole so as to fit it perfectly. A gold disk was let into the top of the plug, and reduced to a level with the surface of the scale. The other end of the plug projected beneath the scale, and had a small hole through it to admit a wire, by means of which it might be turned round. A very fine deep dot was then made by Mr. Dollond upon each of the gold disks, as nearly as it could be done at the distance of thirty-six inches from each other, the dot upon the moveable disk not being exactly in its centre. 44 Captain Kater's account of the Before the plug was ground in its place a small hole was drilled through the side of the scale into the conical aperture. The microscopical apparatus employed on the present occasion has been described in the paper upon the comparison of various British standards of linear measure before quoted. The cross wires of the microscopes being brought respec- tively over zero, and s6 inches upon Sir G. Shuckburgh's scale, the apparatus was transferred to the new standard, and the intersection of the cross wires of one of the microscopes placed upon the centre of the fixed dot. The moveable dot was then brought by turning the brass plug to the intersec- tion of the cross wires of the other microscope. The distance of the dots was repeatedly compared with Sir G. Shuckburgh's standard upon different days, in order to ascertain that no perceptible error remained. A drill was passed through the hole in the side of the scale, and the brass plug carefully pierced through ; a pin was then driven into the plug so as to render any change of position impossi- ble, and the projecting part of the plug was cut off. The standards being thus finished, they were again com- pared with Sir G. Shuckburgh's scale, and it was with surprise and disappointment that I found the whole of them apparently too short. They had been adjusted upon a board of mahogany carefully planed, and the table upon which they were now placed was so flat as to occasion little alteration in a spirit level passed along it. The error of the standards was however far too considerable to be attributed to any curvature which on this occasion could take place, and it was new standards of weights and measures. 45 hot until after several days that I discovered the cause of this perplexing circumstance. I found that by placing a card, the thickness of which w^as accurately one-fiftieth of an inch, under the middle of the standard, the distance of the dots was much increased, and by placing a card of the same thickness under each of the extremities, and withdrawing that which was under the centre, the distance of the dotsi was considerably diminished. The total difference amounted to no less than ,0016 of an inch, whilst the double of the error which would have arisen from mere curvature under similar circumstances would not have been one ten-thou- sandth of an inch. The cause was now evident ; by elevating the middle of the standard, the under surface was shortened, and the upper surface extended ; and on the contrary, when the extremities were elevated the upper surface was compressed and the lower surface lengthened ; the quantity of the effect evidently depending upon the thickness of the bar. Having thus assured myself of the source of the error, a method of obviating it soon presented itself. As the upper and under surfaces of the bar are in different states, the one being compressed and the other extended, there must be an intermediate plane which suffers neither extension nor com- pression, and this plane must be nearly midway between the two surfaces. I therefore caused Mr. Dollond to reduce the thickness of the bar for the distance of an inch and three quarters from its extremities to one half ; the gold disks and plugs were then inserted as before, and the adjustment completed in the manner which has been described. The plugs being secured, and the projecting parts removed, the 4Q Captain Kater's account of the standards were repeatedly compared with Sir G. Shuck- burgh's scale (the standard being placed upon the scale) when no perceptible difference could be detected. Pieces of card were now placed under the standard as before, without occasioning any appreciable alteration ; and I had thus expe- rimental proof of the perfect efficiency of the remedy I had employed. I have been thus particular in detailing the difficulties I experienced, because they exhibit a source of very consider- able error which may arise from the thickness of a standard scale, and which I believe has never before been suspected. It may be here not unnecessary to remark, that on every occasion on which I have used Sir G. Shuckburgh's scale, it has fortunately been placed not only upon the same table, but upon the same part of it. The various standards which have been described in this paper with the exception of the yards with steel termina- tions are not meant for common use, but are intended to be carefully preserved, to be referred to only upon extraordi- nary occasions. In addition however to these, other weights as well as measures of capacity were made with great care by Mr. Bate. The following is a list of the whole, with an account of the places where they are deposited. Standards deposited at the Exchequer ^ Westminster. 1 Imperial standard yard with gold points. I Standard yard with steel terminations. No. i. 1 Imperial troy pound. No. 5. X Avoirdupois pound. No. 1. new standards of weights and measures. 47 1 Avoirdupois pound, No. 5. (in a box with smaller weights.) 1 Weight of imperial gallon of water, No. 1. 1 Imperial gallon measure, No. 3. 1 Bushel, No. 3. 1 Quart, No. 4. 1 Pint. A copy of the imperial Gallon, Quart, and Pint. Bushel, Half bushel. Peck, Gallon, Half gallon. Quart, Pint, Half pint. Gill, Half gill. Set of avoirdupois weights, from 56 lbs. to half a drachm. Set of counterpoises for the above set of weights. 1 Set of troy weights, from one pound to one grain, with counterpoises. 1 for common use. )> cylindrical, for common use. Standards deposited at Guildhally London. 1 Imperial standard yard with gold p(»nts. 1 Standard yard with steel terminations. No. 4. 1 Imperial troy pound. No. 1. 1 Avoirdupois pound. No. s. 48 Captain Kater's account of the 1 Weight of imperial gallon of water, No. 3. 1 Imperial gallon measure, No. 5. 1 Bushel, No. 4. 1 Quart. 1 Pint. 1 Set of avoirdupois weights, from 56 lbs. to half a drachm. Standards deposited at Edinburgh. 1 Imperial standard yard with gold points. 1 Standard yard with steel terminations. No. 2. 1 Imperial troy pound. No. 2. 1 Avoirdupois pound. No. 3. 1 Weight of imperial gallon of water. No. 4* 1 Imperial gallon measure, No. 4. 1 Bushel, No. 1. 1 Quart. 1 Pint. I Set of avoirdupois weights, from 56 lbs. to half a drachm. Standards deposited at Dublin. 1 Imperial standard yard with gold points. 1 Standard yard with steel terminations, No. 3. 1 Imperial troy pound. No. 4. 1 Avoirdupois pound. No. 4. 1 Weight of imperial gallon of water, No. 2, 1 Imperial gallon measure. No. 1 . 1 Bushel, No. s. 1 Quart. 1 Pint. 1 Set of avoirdupois weights, from 56lbs. to half a drachm. new standards of weights and measures. 49 I cannot conclude without bearing testimony to the un- wearied perseverance, ability and accuracy, which Mr. Bate has shown in the course of a work attended with no common difficulties, and to the perfect execution of which he has devoted, for a long period, the whole of his time and attention. From what has been said, it will be seen that the length of the pendulum vibrating seconds in London has been found in parts of the imperial standard yard ; consequently, the value of the yard may at any time be known, having been referred to a natural standard presumed to be unalter- able. The length of the French metre, a standard expressing a certain portion of a terrestrial meridian, has also been given in parts of the English scale. The weight of a cubic inch of distilled water has been determined in parts of the imperial troy pound ; and thus the pound, if lost, may at any future age be recovered. The avoirdupois pound is now for the first time defined, and the measures of capacity are made to depend upon the weight of water they contain ; the impe- rial gallon, containing ten pounds avoirdupois of water, having been declared to be the unit or only standard measure of capacity from which all others are to be derived. This it is to be presumed cannot but powerfully tend to produce uniformity throughout the United Kingdom, by putting it in the power of every individual possessed of standard weights, to verify his measures of capacity with the utmost facility. London, November, 1825. MDCCCXXVI. H 40 Captain Kater's account of the APPENDIX. Table of the correction on account of temperature to he applied to the contents of the Gallon. Temperat. Fahrenheit. 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 Grains. + 35,454 + 33,972 + 32,214 + 30,181 + 27,877 + 25,304 + 22,464 + 19,362 + + + + 15,999 12,379 8,504 4,376 0,000 — 4,623 — 9,489 — 14,596 — 19,942 — 25,522 — 31,335 — 37,377 — 43,646 Difference fori** 1,481 1,758 2,033 2,304 2,573 2,839 3,102 3,363 3,620 3,875 4,127 4,376 4,623 4,866 5,107 5,345 5,580 5,813 6,042 6,269 new standards of weights and measures, 51' POSTSCRIPT. Since the preceding Paper was read, I have received a work on Astronomy, published at Tubingen in 18 n, by Professor Bohnenberger. This work had been pointed out to me by Professor Schumacher as containing a description of the convertible pendulum, and a suggestion of its employ- ment for the purpose of determining the distance between the centres of suspension and oscillation. A friend has favoured me with a translation of the part irt question, by which I find M. Schumacher's information to be perfectly correct, and that the conception of the converti- ble pendulum is not so new as I had imagined when I first engaged in this enquiry. After demonstrating the recipro- city of the centres of suspension and oscillation, the author proceeds to say : ** On a cylindrical or prismatic rod C A " (fig. 102.) let there be placed two wedge-formed axes ** at C and c, whose edges being turned towards each other, " are perpendicular to the rod and parallel to each other. " Let the one be at the end C of the rod, and the other at c, " distant from C something more than two-thirds the length " of the rod, so that the centre of oscillation 0, about the " edge C, may fall between C and c. On the remaining " part, cA of the rod, let a small weight n, slide backwards " and forwards. Now, by a diminution of the mass of the ** rod on one or on the other side, it is easy to manage, that " if this pendulum be suspended on its edge C, a plumb line " hanging down from this, falls upon the edge c, conse- " quently the centre of gravity of the pendulum falls in the ** plane of the axis of rotation. By sliding the weight n, the 52 Captain Kater's account^ &c. " centre of oscillation round C may be made to fall in c, " which is known by the oscillations on C and c being " isochronous. Therefore the distance of the edges is equal " to the length of the simple pendulum which is isochronous " with this compound pendulum/' Although it does not appear that this idea was ever put in practice, it is evident, from the above extract, that the first proposal to determine the length of the seconds pendulum by means of the convertible pendulum, belongs to Professor . BoHNENBERGER, and I take the earliest opportunity of ac- knowledging his claims, in order that the credit of the iirsj: suggestion may re^tjwh^re it J5 so justly due. " ,. |>}p4oa, 3 1 6ji Deceaabejr,j iSf j. ■' ' ' ■ : '! oi:ria) ■Ho f[: c 5s:i II. Description of an improved Hygrometer. By Mr. Thomas Jones. Communicated by Captain Henry Kater, F. R. S. Read June 16, 1825. ___ • Xhe attention of the scientific world has been lately so much occupied in experiments on atmospheric phenomena, that it is hoped any simplification or improvement in the instruments emplojed for that purpose, may not be unac- ceptable. The principle of the hygrometer which I am about to describe, is that of enabling the observer, readily and accu- rately, to ascertain by direct and simple means, the degree of temperature at which the moisture of the atmosphere is con- densed, and the instant at which that operation commences. The hygrometer is composed of a mercurial thermometer, the graduated scale of which is about four inches and a half long ; at the lower part of the scale the glass tube is bent to form a right angle, at the end of which the bulb of the thermometer rises parallel to the scale, and about one inch from it ; the bulb is about one inch long, and of a cylindrical form, with a black convex top, the diameter of which is a little more than that of the cylindrical part, which is covered with silk. The scale is attached to a piece of cylindrical wire, three inches long, and turns upon a joint screw passing into its edge, the other end of which wire being placed in a tubular foot fixed to the inside of one end of the case, forms 54 Mr. Jones's description of an improved hygrometer. SL Stand for the instrument. The case contains a small bottle for ether. The thermometer thus constructed, will give both the tem- perature of the air and that of the dew point ; which last is effected by placing the mouth of the bottle containing the ether, in contact with the upper part of the covered surface of the bulb, when by gently inclining the bottle, the ether will flow downwards without wetting the top of the bulb, which will almost immediately become dull by the deposition of moisture on its surface ; when the observed temperature may be taken and the difference ascertained. Should it be objected against the principle of the instru- ment here proposed, that the indications do not exhibit the true temperature of the upper surface of the bulb on which the deposition of dew takes place, but that of the lower part to which the ether is applied ; it may be answered, that by inclining the whole instrument so as to render the axis of the bulb horizontal, and establish thereby a free circulation of the mercury in every part, this objection may be obviated ; but on repeated trials I have not found this to produce any difference in the results. I ought also perhaps to mention that an instrument some- what similar in principle has been used in Vienna, and was mentioned by Professor Baumgarten of that capital to a friend, who communicated the fact to myself. The instrument is represented in Plate I. Fig. i . THOMAS JONES. 20th February, 1825. mil. Trans. MDCCCXXVI. PlaU \.p.S4. iM. (Sajcie jc i: 5s3 III. Observations on the changes which have taken place in some antient alloys of copper. By John Davy, M. D. F. R. S. In a Letter to Sir Humphry Davy, Bart. Pres. R. S. Read November 17, 1825. Permit me through you to lay before the Royal Society, the results of some experiments and observations on the incrustations of certain antient alloys of copper, which I trust may not be undeserving of notice, whether considered in connexion with the arts of Antient Greece, or in relation to the slow play of chemical affinities acting during a long^ period of time. I shall commence with the most interesting object that I have examined since I have been in the Mediterranean, for which I am indebted to His Excellency Sir Frederick Adam, His Majesty's Lord High Commissioner in the Ionian islands. This is a bronze helmet of the antique Grecian form, recently found in a shallow part of the sea, between the citadel of Corfu, and the village of Castrades. Both internally and externally it is partially encrusted with shells, and a deposit of carbonate of lime. The surface of the helmet generally, both under the incrustation, and where freed from it, is of a variegated colour, mottled with spots of green, dirty white, and red. On minute inspection, the green and red patches exhibit a crystalline structure, and the red very distinctly ; and on examining them with a lens, they were found to be 56 Dr. Davy'5 observations on the changes which have formed of octohedrons of the red oxide of copper, intermixed with crystals of the same form of metallic copper. These crystals are most distinct at the surface ; they even adhere to the calcareous crust, and may be detached with it, pre- senting well- formed facets towards the part from which they have been separated. Chemical examination shows that they are actually composed of metallic copper, without the least tarnish, and of the pure ruby protoxide of copper ; and that the green rust consists principally of carbonate and sub- muriate of copper, and the dirty white chiefly of oxide of tin. The mineralizing process (if I may be allowed the expression) which has produced these new combinations, in general has penetrated very little into the substance of the helmet. The incrustation and rust removed, the metal is found bright beneath ; in some places considerably corroded, in others very slightly. It proves on analysis to be copper alloyed with 18.5 per cent, of tin. Its colour is that of our common brass, and it possesses a considerable degree of flexibility. An antient nail from a tomb in Ithaca, and an antient mirror from a tomb at Samos, in Cephalonia, have afforded me results very similar to the preceding, excepting that the mineralized part, consisting of oxide of tin, submuriate, carbonate, and protoxide of copper, each more or less col- lected apart from the others into little masses, has exhibited rather a crystalline structure than distinct well-formed crystals, and has been without any appearance of crystals of metallic copper. The copper in the mirror I have found alloyed with about 6 per cent, of tin, and a very minute quantity of arsenic and zinc. taken place in some antient alloys of copper. 57 I have examined a select number of antient coins, pur- posely chosen from the fine collection of Dr. Demetrio Petrizzopulo, of Santa Maura, to whose kindness I am indebted for them. The results too which they have afforded are in conformity with the preceding. As this part of my subject may be interesting to the antiquarian, as well as to the chemical enquirer, I shall treat it a little in detail. The very pale incrustations, consisting of a mixture of green and white particles, contain a large proportion of oxide of tin, and a little carbonate of copper, or submuriate of copper, or both. They appear to owe their light hue to the accumula- tion of the oxide of tin at the surface. The black incrusta- tions owe their colour to the predominance of the black oxide of copper, which is commonly mixed with a little protoxide of the same metal, and a minute quantity of oxide of tin, and of the carbonate and submuriate of copper. The coins that I have examined with this crust have contained very little tin. The bluish-green incrustations consist chiefly of carbonate of copper, either without oxide of tin, or mixed with a small proportion of this metal. The emerald-green incrustations abound in the submuriate of copper, and the red consist almost entirely of the protoxide of copper. These two compounds I have never witnessed spread over the whole of a coin, but more or less mixed with rusts of a different kind, studding the surface in the form of little crystalline elevations. It is natural to enquire — is there any connexion between the chemical composition of the incrustations of antient coins, and their texture ; some being remarkably smooth, and as MDCCCXXVI. I 58 Dr. Davy's observations on the changes which have it were polished, preserving admirably the original impression of the die ; whilst others are rough and deformed ? I am disposed to reply in the negative, not having yet discovered such a connexion ; excepting thus far, that the protoxide of copper, and its submuriate, frequently appear in minute crystalline elevations rising above the surface of the coin. Generally, I suspect the difference of texture in question depends on other circumstances, and very likely in different degrees of rapidity of operation of the mineralizing cause. It is a curious question for consideration, the manner in which the crystalHne structure is acquired exhibited by these incrustations ; and still more so, how crystals are formed, especially such as were discovered on the helmet, and on the adhering calcareous deposit. There being no reason to sup- pose deposition from solution, are we not under the necessity of inferring, that the mineralizing process witnessed in its effects, depends on a slow motion and separation of the particles of the original compound ? and, must we not con- clude, that this motion is connected with the operation of electrochemical powers ?* Supposing the oxides first formed upon the bronze in a state of negative electricity, with respect to the metal, their agency, in a long course of ages would be to separate the least oxidable metal, the copper, in its pure form ; and all the changes are such as may be accounted for from agencies of the same kind, but of different intensity. And may not similar explanations be given of other like * The separation of the copper from the tin in the bronzes found in the ancient cities destroyed by volcanic eruptions, must be referred to another source ; namely, the crystallizations dependent upon degrees of heat a little below the point of fusion of the alloy. taken place in some antient alloys of copper. 59 phasnomena, which often seem to» occur in the mineral kingdom ? These facts offer an obvious practical application, both in determining the antiquity and genuineness of ancient works of art ; for aerugo of the kind which I have described could not be successfully imitated by any artificial processes ; and a very slight chemical examination, or even one by the lens, would be sufficient to expose any fraud attempted to be practised by substituting modem imitations for ancient works. I am, most truly yours, J. DAVY. To Sir H. Davy, Bart, Pres. R. S. ceo 3 IV. Additional proofs of animal heat being influenced by the nerves. By Sir Everard Home, Bart. V. P. R. S. Read November 16, 1825. 1 HE conclusions drawn from my experiment upon the deer's horns, published in the last volume of the Philoso- phical Transactions, are so important, that I felt it a duty to repeat the experiment in the ensuing season. This I have done, and have the satisfaction to find that the result agrees in every respect with that drawn from the first experiment. For the present experiment, I was furnished with a buck of full head, seven years old, and in good condition ; the former not having suffered from what was done in any respect whatever. As several disadvantages had arisen in the former experi- ment from the horns having been bored ; they were now pre- vented by applying a cincture of knitted worsted round that part of the palm, the heat of which was to be ascertained, three inches broad ; and the bulb of the thermometer was received between this and the velvet of the horn. As soon as the temperature was taken, the cincture was removed. All liability to external injury was precluded, by confining the animal in a stable. A circumstance favourable to put the result of this experi- ment to the severest test was, the heat of the atmosphere being very different from that in the former season ; during Sir EvERARD Home's additional pooofs , ^c, 61 the time of the experiment in 1824, it was 66^, in 1825, 84", a difference of 18°. This experiment was begun on the 12th of July, 1825, at three o'clock. The temperature of the atmosphere was 84°, that of both horns exactly 98 j . Immediately after Mr. Mayo had divided the nerves, the heat of that horn was diminished to 93 i°, and the heat of the other encreased to 99°. The following register, showing the changes that took place in the temperature of the horns and atmosphere, was regularly filled up every day at three o'clock. Day Heat of Heat of Horn Heat of the of July. Atm. operated on. other Horn. 12th 84° 9Si'' 99' 13th 84 93 98 14th 84 93 100 15th 85 96 99 I6th S6 91 99i 17th 86 91 99 I8th 86 90| 98 19th 86 91 99 20th 85 91 99 21st 75 96 91 22d 76 93 93 2sd 74 93 93 After the two horns had become of the same temperature the buck was allowed to join the herd. On the 28th of July it was killed for the use of the table, which gave me an op- portunity after death of examining the parts that had been operated on. The horns had not shed their velvet, were exactly of the same size, and equal in solidity. ^% Sir EvERARD Home's additional proof s of the The parts where the nerves had been divided were care- fully dissected and examined by Mr. Mayo, Mr. Caesar Hawkins, and myself. The two cut ends of the nerves had receded from one another, and the interval between them was occupied by a dense newly-formed substance, which had become a firm connecting medium, explaining satisfactorily the restoration that had taken place in their functions. In the former experiment this connecting medium was less dense, and left a doubt upon my mind, which is now com- pletely removed. While engaged in this investigation I have had an oppor- tunity, in the course of my professional duty as Surgeon to Chelsea Hospital, to ascertain the effect of tying the trunk of the artery that supplies the human thigh and leg on one side, upon the temperature of the limb, compared with that of the other, which remained in a natural state ; and con- trasting this with the effect that has been stated to take place when the nerve of one horn is divided. As I intend to lay before the Society the detail of the treatment of this case, of an aneurism in the external iliac artery of the right side, which I trust will tend to the ad- vancement of the science of Surgery on a future occasion, I shall confine myself at present to the effect produced upon the temperature of the limb, when the femoral artery is obliterated immediately below Popart's ligament. Before the artery was included in a ligature, the tempe- rature of the foot, ascertained by a thermometer, was 93°; that of the left, which was in a state of perfect health, 84°. In ten minutes after the operation the heat of the foot fell to 87° ; in 30 minutes to 85, while the left foot remained at 84*. source of animal heat being in the nerves, 63 In eight hours the heat of the left foot rose to 94**, probably from the increased quantity of blood circulating through its arterial branches, since next day the temperature fell to 88', at which it continued stationary for four days ; the foot of the aneurismal side in 24 hours fell to 84°, but on the following day rose to 85°, and continued at or above that temperature till the ligature came away. Nothing can have been more satisfactorily proved than that the heat of the parts of the body is diminished by dividing the nerves going to them ; while, on the other hand, obstruct- ing the arterial trunk of the thigh, even before it sends off the great muscular branch, does not diminish the heat in the smallest degree below the natural standard. I have had many opportunities of ascertaining the tempe- rature of the foot after the femoral artery has been tied in the operation for the popliteal aneurism, and found it com- monly one degree below that of the other foot, but the heat of the two feet had never been ascertained before the opera- tion, so that I was most probably deceived in the conclusion I had drawn ; and in reality, the heat of the other foot had been raised above the standard, instead of having been depressed below it. C64 3 V. The Croonian Lecture. On the structure of a muscular fibre from which is derived its elongation and contraction. By Sir EvERARD Home, Bart. V. P. R, S. Read December 15, 1825. J.N the course of the last 40 years I have given this Lecture more frequently than any Member of the Society ; and, like my predecessors, on those occasions, have taken up the sub- jects most nearly connected with the inquiry for which the Lecture was instituted. As far back as the year 1818, while considering the mode in which coagulated blood is rendered vascular, I brought forward a magnified drawing of a muscular fibre made by Mr. Bauer, showing it to be composed of a single row of globules — ^ — parts of an inch in diameter, or in other words, of red 2,000 ^ ' ' globules deprived of their colouring matter. From that time I had not proceeded further in investi- gating muscular structure, but the appearance of the nervous fibres of the great splanchnic ganglion in Mr. Bauer's mag- nified drawings, which I laid before the Society last spring, led me to consider that the organization of these fibres must be so closely allied to that of muscles, that every physiologist who examined the drawings, must immediately come to the same conclusion ; and no sooner would those drawings be in the hands of the public, than any one might with the greatest Sir EvERARD Home on the structure of a muscular fibre, &c. 65 ease complete the discovery by an actual examination of muscular fibres in the microscope. Under this impression, I requested the President to appoint me to give this Lecture, wrhich is to be read nearly at the same time my paper on ganglions will be published ; so that no one will have an earlier opportunity of applying what is said of nerves in that communication to muscular fibres, the consideration of which is the object of the present Lecture. In Mr. Bauer's former examination of muscular structure, that the integrant fibre might be more easily separated from the fasciculus to which it belonged, we had gone into the same error with those physiologists who have made diagrams of the internal appearance of the brain, after coagulation, and had boiled the muscle previous to the examination ; not being aware that this process must decompose red globules, should any exist, and cause the colouring matter to be sepa- rated. Boiling would also destroy any connecting medium by which the globules are united together ; so that, if I may use the expression, there would only be the skeleton of a muscular fibre remaining to be examined. Upon the present occasion, therefore, the fibres belonging to the fasciculi that compose the great muscle that lies upon the back of the bullock's neck, to raise the head, were selected, and were examined in 24 hours after the animal was killed ; and we know that in all violent deaths, the muscular fibres continue capable of contraction beyond that period, after apparent death has taken place. In this muscle the fasciculi are more loosely connected together than in almost any other animal body ; and in the interstices between them there is no fat ; but Mr. Bauer MDCCCXXVI. K 66 Sir EvERARD Home on the structure of a muscular fibre found that in this recent state the fibres are held so firmly together by the mucus which surrounds them, and forms them into fascicuh, that it was only under water he could separate an integrant fibre for examination in the field of the microscope. In its mechanism, he found it to correspond with the nervous fibre of a gangHon, differing only in the size of the globules, which were larger than those of the fibre in the ganglion in the proportion of —^ parts of an inch to — ^ and — ^— parts. 4,000 ^ ■■- The elastic transparent jelly uniting the globules together, had not the same elasticity as in the nervous fibre, so that it could not be drawn out from the contracted state to double its length without breaking. The muscular fibre of a trout was treated in the same way, and the result was the same ; the fibres were however more brittle than those in the bullock's neck. From these facts, in addition to those communicated in the examination of the structure of ganglions, it is at last ascertained, that the structure of the fibres of nerves in general, and those peculiar to ganglions, as well as those that compose muscles, is so far the same, that they consist of single rows of globules united together by an elastic gelati- nous transparent matter ; they differ however in the size of the globules, and the degree of elasticity of the medium by which they are united ; so that a less power will elongate a nerve than the fibres of a muscle, and to a greater extent, and it will restore itself with more velocity to a state of rest. This structure of nerves and muscles, I consider to be from which its elongation and contraction is derived, 67 demonstrated in the annexed drawing ; since I cannot believe Mr. Bauer has been led into any error upon this occasion ; as no error has been detected in his microscopical observations for so many years continued, and the accuracy of his representations, of what he has seen, no one can doubt. It is a curious confirmation of the acuteness of his eye, and the accuracy of his glasses, that Leuwenhoek, who used a single microscope, and says it is the best that can be made, since the magnifying glass is the smallest speck that can be seen, declares a muscular fibre to be made of globules less than the red globules of the blood ; and Dr. Monro of Edinburgh, who published his microscopical observations on nerves and muscles, in the year 1783, made chiefly in the solar microscope, goes so far as to consider muscular fibres to be the continuation of nervous fibres, and gives an en- graving of the mode in which the one terminates, or is lost in the other. Dr. Monro, it is evident, had never seen a single fibre either of a nerve or muscle, only fasciculi of them, and found them so much alike as to be led to consider them the same. Both Leuwenhoek and Monro, from the want of a micrometer, were left to guess at relative dimension, and in such guesses were often very unsuccessful. The globules in the nervous fibre being smaller than in the muscular, oversets Monro's theory of their being the same ; but that both authors, with means so very inadequate to those employed by Mr. Bauer, should have made such approaches to the truth, is highly creditable to them, and must prove highly satisfactory to Mr. Bauer, as well as to the public. 68 Sir EvERARD Home on the structure, &c. EXPLANATION OF PLATE IL It represents muscular fibres magnified in different degrees. Fig. 1. A fasciculus of fibres taken from the bullock's neck, sufficiently dissected to show the separate fibres ; magnified loo diameters. Fig. 2. A portion of the same fasciculus, the fibres more unravelled ; magnified 200 diameters. Fig. 3. A portion of a fibre in its contracted state, con- sisting of five blood globules, and exactly one inch in length, taken from the bullock's neck ; magnified 400 diameters. Fig. 4. The same length of fibre extended to its utmost, without giving way ; magnified 400 diameters. The calf was selected for this last purpose, the elastic medium between the globules being less brittle in the young than the full grown animal. J'Ml. Trnns. tADCOCSXTl.J'laZe XLp.SS. ^^rvjStoMi <^- CegH VI. An account of the heat of July, 1825 ; together with some remarks upon sensible cold. By W. Heberden, M. D. F. R, S. Read January 12, 1826. A.S I think it may not improbably be deemed an object of some curiosity to the Royal Society to collect from different parts, an account of the very unusual heat of last July, I presume to offer the enclosed report of observations which I made at that time, at Datchet, in Buckinghamshire, with every precaution that suggested itself to me, to ascertain the real temperature of the atmosphere, uninfluenced by adven- titious circumstances. The observations were made with a small sensible thermometer, which had been carefully graduated. On Friday July 15, the wind blowing from the south-west, the thermometer was suspended in the shade of a large laburnum on my lawn, at a height of about five feet and a half from the ground. This tree was chosen, as admitting the air in some degree to pass through it, at a time when the wind and the sun were both in the same quarter. On the subsequent days, the wind being in the east and north-east, the thermometer was hung, at about the same height, from an external branch of a very thick Portugal laurel, standing likewise upon the lawn, at a distance from any building; where it was exposed to the full influence of the wind, and at the same time effectually sheltered either from the actual 70 Dr, Heberden's account of the heat of July y 1825 ; rays of the sun, or from any object heated by it. I have been the more particular in giving this account, because it is often difficult, especially in great, or rapid changes of tem- perature, to get observations made with sufficient attention to avoid the neighbourhood of buildings, or other objects, which may considerably affect the thermometer, and give an appearance of heat sometimes greater, sometimes less than the truth. ■ In order to ascertain the greatest heat, the thermometer was repeatedly examined at short intervals during the hottest period of the day. The highest degrees indicated, under the circumstances I have detailed, were as follows : July 15. - - 92° wind S. W. 17. - - 90°^ 18. - - 96° [wind E. 19. - - 95°^ The 16th is not set down, because, though it was a hot day, yet being several degrees cooler than the day preceding, it was not thought worth while to examine the thermometer with the same attention. There is some reason to believe that an unusual degree of heat was felt about the same time, not only in most parts of Europe, but also in America. The only instance of heat, that I am aware of having been noticed in England equal to this, was in July 1808 ; on the 13th of which month the thermometer is stated, in the Meteorological Journal of the Royal Society, to have risen to 93 J . On the 12th it had stood at 90°, and on the 14th it was 91° ; the wind at the same time varying from east to together with some remarks upon sensible cold, 71 south and south-west. On the hottest of these days Mr. Ca- vendish's thermometer at Clapham rose to 96°. It is true that other accounts have been recorded, some in the Transactions of this Society, of hot days, or hot seasons, which may have equalled, or possibly surpassed this: but till within the last sixty years, the use of the thermometer had hardly been understood sufficiently to enable one to rely upon the vague statements of earlier times. - To persons who may wish to compare this with the heat of tropical countries, it will not be thought superfluous to add, that the late Dr. Hunter, whose accuracy is well-known to many members of the Royal Society, has stated in his valuable account of diseases in the West Indies, that the range of the thermometer at the hottest part of the day, and in the hottest season of the year, at Kingston, in Jamaica, is from 85** to 90®. In the coldest season it is about 5° lower. It is not the least singular circumstance attending the heat of last July, that it should have subsided without rain, without lightning, without any change of wind, or any obvious cause ; the succeeding days continuing dry and fair, as those before. I am tempted to add to the above some other observations, which, if they are not immediately connected, are not entirely unconnected with this subject; for it cannot have escaped the attention of any person moderately conversant with natural philosophy, that the index of a thermometer is a very imperfect measure of what I may call the sensible cold, that is, of the degree of cold perceptible to the human body in its ordinary exposure to the atmosphere. For while the ther- mometer truly marks the temperature of the medium in 72 Dr. Heberden's account of the heat of July, 1825 ; which it is placed, the sensations of the body depend aUoge- ther upon the rapidity with which its own heat is carried off. And this is by no means confined to the actual temperature of the air ; but whatever alteration of quality increases its power of conducting heat ; and, above all, whatever currents increase the succession of its particles in contact with the body, the same will increase the sensation of cold. Hence it is, that in very hot weather, the same stream of air which would heat a chamber, will nevertheless be cool to the feel- ing ; on the other hand, when the thermometer was more than 80° below the freezing point, Captain Parry observed, that while the air was still, the cold was borne without in- convenience. It therefore occurred to me, that the proper way to esti- mate the sensible cold, would be, first to raise a thermometer to a height something exceeding the natural heat of the human body, and then to observe at what rate the quicksilver contracted upon exposure to the air. For this purpose I used a thermometer with a very small bulb, which might show the alteration of heat in a short time. This I held to the fire till it rose to about 120**, and then carried it in a warm glove into the open air. I had with me an assistant with a watch in his hand : and as soon as the mercury had descended to 100°, he began to count the seconds, while I continued to observe the thermometer, marking the degree of heat at the end of every ten seconds during half a minute. The result rather exceeded my own expectations ; and (being, as far as I know, the only experiments of the kind, ) I have thought the Society might not dislike to be made acquainted with them. together with some remarks upon sensible cold. 73 The circumstances that particularly engaged my attention were wind, and moisture. With these views the following experiments were made, and verified by repeated trials. Experiment i. 1 82 1 , January 3. A strong east wind. The temperature of the air 31°. The thermometer in this, and all the experiments, being previously raised to 100°, in the manner before-men- tioned, the descent of the mercury from that point was observed as fol- lows : After 10" it was 78®. Decrement 22** 20" 60° 18° 30" 52° 8° By the decrements, it is to be under- stood the descent in each successive ten seconds. This is added, because I consider it as the proper measure of the sensible cold, so long as the ther- mometer retains a heat approaching to that of the human body. Experiment 2. 1821, Jan. 4. No perceptible wind. The temperature of the air 30°, the atmosphere hazy. After 10" therm. 89® Decrement 11* 20" 800 III 9*> 30" 71° 9° Experiment 3. 1 8a I, Feb. 10. A strong east wind. Temperature of air 47°. The atmo- sphere clear, with sunshine. After 10" therm. 82° Decrement 18° 20" 30" 73° 640 Experiment 4. 1 824, Jan. 9. A cold fog. No wind. Temperature of the air 370. After 10" therm. 92° Decrement 8*^ 20" 85° 70 30" 790 6° The most superficial view of these experiments shows the prodigious effect of wind to increase the rate of cooling, which, I apprehend, constitutes sensible cold ; so that in experiment 3, though the thermometer suspended in the open air was 17° higher than in experiment 2, yet the sensible cold was very considerably greater ; but when there was no wind, even a wet fog did not much, if at all, increase it. This, which at first sight may appear contradictory to experience is not, I believe, really so ; for though the power of such air to carry off the heat of the body be indeed increased, yet so long as we remain at rest, we are in great measure unaffected by it ; MDcccxxvr. L 74 Dr. Heberden's account of the heat of July, 1825 ; &c, so much the effect of wind exceeds that of mere moisture. It is by walking, or riding, in such a state of the atmosphere, that we produce on our bodies a current of moist air, which is then felt in proportion to the rapidity with which we pass through it. If it were thought worth while to bring this to the test of the thermometer, the instrument should be made to pass through the air at the same rate as the person would move. i:75D VII. On the transit instrument of the Cambridge Observatory ; being a Supplement to a former Paper. By Robert Wood- house, Esq. Plumian Prof essor of Astronomy in the University of Cambridge. Read January 19, 1826. Jln the brief account of the transit instrument which I had the honour some time ago of presenting to the Royal Society, I stated the circumstance of the instrument's devia- , tion from the meridian arising from the unequal expansion of its braces ; but no instance was then given of the magnitude of such deviation. I now subjoin one. On the morning of Oct. 15, (civil reckoning) after ob- serving the passage of Regulus, the southern shutters were accidentally left open, so that when I returned to observe the inferior culmination of the pole star, the sun was shining on the upper western brace, the object-glass of the instrument being towards the zenith. The effect of this was a retarda- tion of more than 25 seconds in the star's passage, as will thus appear : -J Oct. 14. { o''59"20'' Polaris. Rate of Clock 12 69 44 Polaris S. P. — .17 Oct. 15. 1 0 59 20 12 59 17 Polaris. Polaris S. P. -^ Oct. 16. 0 59 19-5 Polaris. Reversed the > axis. Oct. 17. 0 59 20 Polaris. &c. 76 Mr. WooDHousE on the transit instrument, &c. I now view, with great suspicion, all the observations of the sun's transits, which I observed previously to the de- tection of that source of inequality which is the subject of the present, and of my former communication. C77 3 VIII. Account of a series of observations y made in the summer of the year 1825, for the purpose of determining the difference of meridians of the Royal Observatories of Greenwich and Paris ; drawn up by J. F. W. Herschel, Esq. M. A. Sec. R. S, Communicated by the Board of Longitude. Read January is, 1826. Operations having been carried on to a considerable extent in France, and other countries on the continent, for the purpose of ascertaining differences of longitude by means of signals, simultaneously observed at different points along a chain of stations ; and the Royal Observatory at Paris, in particular, having been connected in this manner with a number of the most important stations, it was considered desirable by the French government that the Royal Observa- tory at Greenwich should be included in the general design. The British Board of Longitude was accordingly invited to lend its co-operation towards carrying into effect a plan for that purpose ; and the invitation being readily accepted on their part, I was deputed, in conjunction with Capt. Sabine, in the course of the last summer, to direct the practical details of the operation on the British side of the channel, and to make the necessary observations. Every facility was afforded us in making our dispositions, on the part of the different branches of His Majesty's government to which it was found necessary to apply. A detachment of artillery was placed, by his Grace the Duke of Wellington, Master 78 Mr, Herschel's account of a series of observations General of the Ordnance, under the orders of Capt. Sabine. Horses, waggons, and men, were furnished for the convey- ance of a tent, telescopes, rockets, and other apparatus ; and four of the chronometers belonging to the Board of Admi- ralty were placed at our disposal. The rockets required for making the signals were furnished us from France. It would have been easy, doubtless, to have procured them from the Royal Arsenal at Woolwich ; but on the representation of Colonel Bonne, to whom the principal direction of the ope- rations in France was intrusted, it was thought more advis- able to accept an offer made to us of any number which might be required, prepared at Paris expressly for similar operations, carrying a charge of 8 ounces of powder, the in- stantaneous explosion of which, at their greatest altitude, was to constitute the signals to be observed. Our previous arrangements being made, on the 7th of July I left London; and after visiting the station pitched upon at Wrotham, which was the same with that selected by Capt. Kater and Major Colby, as a principal point in their triangulation in 1822; and finding it possessed of every requisite qualification for the purpose of making the signals, from its commanding situation, being unque;stionably the highest ground between Greenwich and the coast, pro- ceeded to Fairlight Down, near Hastings, where I caused the very convenient observatory tent, belonging to the Board of Longitude, to be pitched immediately over the centre of the station of 1821, which was readily found from the effectual methods adopted by the gentlemen who conducted the trigonometrical operations in that year, for securing this valuable point. Here, on the 8th, I was joined by Capt. for determining the difference of meridians, &c. 79 Sabine, who, it had been arranged, should proceed to the first observing station on the French side of the Channel, there to observe, in conjunction with Colonel Bonne, the signals made on the French coast, and those made at the station of Mont Javoult ; which latter were to be observed immediately from the observatory at Paris ; while, on the other hand, it was agreed that M. le Lieutenant Largeteau, of the French corps of geographical engineers, should attend at Fairlight, on the part of the French commission, and observe, conjointly with myself, the signals made at La Canche, the post on the opposite coast (elevated about 600 feet above the sea, being nearly the level of Fairlight Down) and also those to be fired from Wrotham Hill, which were expected to be immediately visible from a scaffold, raised for the purpose on the roof of the Royal Observatory of Green- wich. By this arrangement, and by immediate subsequent communication of the observations made at each station, it was considered that the advantage of two independent lines of connexion, a British and a French, would be secured between the two extreme stations; i. e. the two national observatories ; every possibility of future misunderstanding obviated, and all inconvenience on either side, arising from delay, or miscarriage in the transmission of observations, be avoided. With the assistance of Capt. Sabine, and by the help of exact information as to the azimuths of Wrotham and other nearer stations in the triangulation of 1821, with which Capt. Kater had obligingly furnished us, and of which Fairlight Church proved the most convenient, being close at hand and favorably situated, and easily visible in the twilight ; and 8o Mr. Herschel's account of a series of observations from the previously calculated azimuth of La Canche (114° 30' E.); four night glasses by Dollond, provided at the order of the Board of Longitude expressly for this opera- tion, and which I had caused to be fixed on posts firmly driven into the ground beneath the tent, were then pointed, two on the station of La Canche, and two on that of Wrotham Hill. Those directed to the former were of four inches clear aperture, the others of three. In case of any difficulty arising as to the pointing, I had taken care to provide myself with an excellent eight-inch repeating theodolite, on the Reich- ENBACH construction, by Schenck, of Berne ; but it was found unnecessary to use it, as the night glasses were purposely constructed with an azimuthal motion, and a rough gradua- tion read off by an adjustable vernier, so as to allow their being set at once a few minutes before the observations com- menced, by taking Fairlight steeple as a zero point ; a cir- cumstance which proved exceedingly convenient, as it allowed of their being dismounted after each night's observations, and removed to a place of security ; and thus rendering it unnecessary to harass our small party by keeping guard in our absence. On the night of the 8th I had directed blue lights to be fired at Wrotham, as a trial of the visibility of the stations, or rather as a verification of the pointing of the telescopes ; for on the former point there could be no doubt, the station at Wrotham being situated precisely on the edge of the escarpment of the chalk which borders the Weald of Kent, and having been actually connected with Fairlight by direct observation, while no obstacle but a low copse wood, over which it might fairly be presumed that no rocket would for determining the difference of meridians ^ &c. 8 1 fail to rise, separated it from a direct view of Greenwich, at about 20 miles distance. Either from haze in the at- mosphere, or from the too great distance, nothing was seen that night or the next ; which however caused no unea- siness, as we could depend on our instruments and informa- tion. The next morning Capt. Sabine quitted Hastings, and joined Col. Bonne, at his post, on the morning of the 10th, the day appointed for the commencement of the observations ; meanwhile I was joined by M. Largeteau, who remained with me the v/hole time of their continuance, performing every part of a most scrupulous and exact observer, as the observations herewith communicated will abundantly testify. The observations were continued during 12 nights, 10 signals being made at each rocket station every night. The weather throughout the whole of this time was magnificent, and such as is not very likely to occur again for some years ; a circumstance of the last importance in operations of this nature, where lights are to be seen across nearly 50 miles of sea, and also by reason of the verification of the sidereal times at the observatories by transits. One night only a local fog deprived us of the sight of 1 3 out of the 20 signals ; but on the whole, out of 120 made at Wrotham, no less than 112 were seen from Fairlight (about 40 miles) and 89 from Greenwich ; while out of the same number made at La Canche, qs were observed at the former post. I am sorry to add, however, that owing to a combination of untoward cir- cumstances, which no foresight or exertion on the part of Capt. Sabine or myself could possibly have led us to calcu- late on, or enabled us to prevent, and which the most zealous endeavours on that of Col. Bonne failed to remedy, no MDCCCXXVI. M \ 8d Mr. Herschel's account of a series of observations less than eight out of the twelve nights' observations were totally lost, as to any result they might have afforded, and the remainder materially crippled ; so that a much more moderate estimate of the value of our final result must be formed, than would otherwise have been justified. Still it is satisfactory to be able to add, (such is the excellence of the method) that a result on which considerable reliance can be placed, may be derived from the assemblage of the observa- tions of these four nights ; and when it is stated that this" result appears not very likely to be a tenth of a second in error, and extremely unlikely to prove erroneous to twice that amount, it will perhaps be allowed that, under such cir- cumstances, more could hardly be expected. for determining the difference of meridians, &c. S8 I. Observations made at the Royal Observatory at Paris. Station de I'Observatoire Royal. Feux de Mont-Javoult. J s« Apparition des Signans. Noms Avance as des Observateurs. Pendule sur le tems Sideral. 3 —> Observes en tems de la Pendule. En tems Sideral. Remarques. A* B « 7 iS"* 15' 52".© 52.2 52.0 IS'' i5'4o''.3 40.5 40-3 Mathieu Savary Nicollet brillant eleve. 8 26 17.5 26 5.8 Mathieu - excessiyement faible : observation douteuse , i8 9 35 52.9 53-1 52.5 35 41.2 41.4 40.8 Mathieu Savary Nicollet ii".7 tres brillant, assez eleve. 10 45 56.0 55-9 45 44-3 44.2 Mathieu Savary - faible, peu eleve. 55.6 53-9 1 Nicollet t So in the original. (H.) S I 17 19 49.8 49.8 17 19 37.0 37-0 Mathieu Savary - - brillant. 2 29 42.4 29 29.6 Mathieu - faible, eleve. 5 59 44.4 44.6 59 31-6 31.8 Mathieu Savary ~ ~ assez brillant, peu ^leve. »9 6 18 9 58.1 58,1 18 9 45.3 45-3 Mathieu Savary 12.8 assez brillant, peu eleve. 8 29 54-3 54-4 29 41.5 41.6 Mathieu Savary ~ peu brillant. 9 40 5.5 5.1 39 527 52-3 Mathieu Savary ~ ~ brillant, tres eleve. 10 49 56-3 56.1 49 43-5 43.3 Mathieu Savary ~ " brillant, tres elev6. s 2 17 33 507 »7 33 36.5 Mathieu - > tres faible, observation tres douteuse. 3 43 45-5 45-5 43 31-3 3»-3 Mathieu Savary brillant, assez eleve. 4 53 49-8 53 35.6 Mathieu - tres faible, bas. 5 18 3 46.7 46.8 18 3 32.5 32.6 Mathieu Savary ~ tres brillant, tres clev^. 20 6 13 48.6 48.1 '3 34-4 33-9 Mathieu Savary 14.2 assez brillant. 7 23 49-9 49-7 23 35-7 35'5 Mathieu Savary ~ " peu brillant, assez ^leve. 8 33 53-3 53-6 33 39-1 39-4 Mathieu Savary - peu brillant, assez eleve. 9 43 56.3 56.4 43 42.1 42.2 Mathieu Savary - brillant, tres eleve. 10 53 54.2 54.6 53 40-0 40.4 Mathieu Savary brillant, tres eleve. • La colonne (A) renferme les nombres qui ont ete trouves par les observations des feux. La colonne (B) renferme les nombres de la colonne (A) corriges de I'avance de la pendule. Les nombres de la colonne (B) sont ceux qui doivent etre compare au tems sideral absolu de Greenwich. 84 Mr. Herschel's account of a series of observations Observations made at the Royal Observatory at Paris. Station de I'Observatoire Royal. Feux de Mont-Javoult. J £g Apparition ( les Signaiix. Noms Avance des Pendule sur le terns Remarques. •^s s 1— i 5Q Observes en terns de la Pendule. En terns Sideral. Observateurs. Sideral. A B % I 17^27' 43."2 43-5 i7h27'26."8 27.1 Mathieu Savary - peu brillant, peu elevd. 2 i7 39-5: 37 23-1: Mathieu - brillant, tres eleve, j'ai viTune trainee lumineuse de 37" a 40" j'estime le grand eclat vers 39".S. 3 47 48-3 48.7 47 31-9 32.3 Mathieu Savary - assez brillant, tres eleve. 4 57 42-3 57 25.9 Mathieu . faible, peu eleve. 59.6 43-2 Savary . autre feu brillant et tres elevd. 5 18 7 375 18 7 21. 1 Savary - tres faible, bas. 21 7 57.3 57-4 7 40-9 41.0 Mathieu Savary i6".4 autre feu assez brillant et eleve. 6 17 41-3 17 24.9 Savary - faible et peu eleve. 17 46.8 »7 30-4 Mathieu . - autre feu assez brillant, eleve. 46.6 30.2 Savary 7 27 46.5 27 30-1 Mathieu - assez brilliant et eleve, explosion non instantanee. 46.4 30.0 Savary 8 37 51.6 37 35-2 Savary « • faible et bas. 37 57-2 37 40-8 Mathieu . tres brillant et tres eleve. S7''^ 40.7 Savary lO 57 S^'7 57 40-3 Savary . premier feu, assez brillant, mais bas. 58 0.3 57 43.9 Mathieu - - autre feu, tres brillant, assez eleve. ? I 17 31 29.9 29.6 17 31 12.3 12.0 Mathieu Savary - - tres brillant, tres eleve. 2 41 29.3 29-3 41 11.7 11.7 Mathieu Savary * assez brillant, peu eleve. 3 51 36.2 51 18.6 Mathieu - assez brillant et eleve. 36.4 18.8 Savary •"i-j 4 18 I 33.3 18 I 15.7 Mathieu - assez brillant et eleve. 22 33-2 15.6 Savary 17.6 5 " 39-4 39-2 11 21.8 21.6 Mathieu Savary " tres brillant et assez elev6. 6 22 1.3 I.I 21 43-7 43-5 Mathieu Savary * assez brillant et eleve. 7 31 49-3 49-5 31 3»-7 319 Mathieu Savary " assez brillant et assez eleve. 9 S» 47-5 47-3 51 29.9 29.7 Mathieu Savary assez brillant et assez eleve. On a observe les signaux de feu donnes a Mont-Javoult pres de Gisors dans un petit cabinet situe dans comparais, a I'aiae d'un chronometre, la pendule a celle qui Ces comparaisons m'ont donne pour chaque jour I'avance de la pendule des feux sur celle de la lunette meridienne et par suite sur le tems sideral. Je me suis attache a regler la pendule, qui est pres de la lunette mferidienne par les passages durant le jour des sept ^toiles suivantes : Aldebaran, La Chevre, Rigel, a Orion, Arcturus, « Couronne, a Serpent. J'ai observe 5^ de ces etoiles le 18, 3 le 19, 7 le 20, 4 le 21, et 5 le 22. J'ai calcule leurs positions apparentes d'apres les positions moyennts et les corrections in Right Ascension donnees par Mr. South. L. MATHIEU. for determining the differe7ice of meridians, &c. 85 II. Captain Sabine's observations at Lignieres. Chronometer of Motel, No. 39. servations du 18 Juillet, huitieme jour. Ob Observations du 19 Juillet, le neuvieme jour. Apparition des Signaux, en terns de la montre. Apparition des Signaux, en terns de la montre. Remarques. Remarques. i I'Orient. i I'Occident. f i I'Orient. i I'Occident. I b. niin. sec. h. min. sec. I h. min. sec. li. min. sec. 2 2 9 39 30-4 fa. du. 3 4 5 6 9 49 33*4 9-59 34.0 10 09 37,2 10 19 33,6 9 54 52, non vu. 10 14 54,du non vu. Signal de La Canche [faible. Signal de La Canche [tres faible. 3 4 5 6 10 09 39,6 9 44 10 14 50 50^4 7 10 29 34,4 id. 7 - 10 34 49,6 8 non vu. id. 8 9 10 49 328 id. 9 10 49 41,2 10 54 53,6 10 10 59 33.6 id. 10 10 59 30,0 II 05 01,4 Le Colonel Bonne a Mont-Javoult, moi seul. Les signaux de Mont-Javoult bien vus, except^ le 7"'e qui etait faible. • Observations du 20 Juillet, le dixieme jour. Apparition des Signaux, en tems de la montre. A Remarques. r i I'Orient. 1 ^ I'Occident. I 2 3 4 5 6 7 8 9 10 h. min. sec. 9 49 39'6 10 09 27'6 10 29 27*2 10 49 30-5 li. min. sec. 10 54 47-6 faible. Observations du 21 Juillet, le onzieme jour. I 2 3 4 5 6 7 8 9 10 Apparition des Signaux, en tems de la montre. r- ' , i I'Orient. b. |min. sec. 9 39 24-8 9 49 32-8 10 09 38-4 10 19 26*4 10 39 33-2 10 59 33-2 i I'Occident. b. min. sec. 9 34 50-8 9 54 50-4 10 04 53*2 10 14 51.2 10 34 49-6 10 44 59-4 11 04 52,0 Remarques. Le 6'ne signal de Mont-Javoult rasant rhorizon. 86 Mr. Herschel's account of a series of observations Captain Sabine's observations of signals seen from Lignieres. /-M I.:. _ J.. T.. ti-i yjubcivmiuiis uu zz juiiici.> 12""* jour. Apparition des Signaux, eu tems de la montre. Remanjues. • a I'Orient. 4 roccident. I h. miu. sec. 9 29 1 8*6 h. min. sec. 9 34 55'6 2 - 9 44 50*8 3 9 49 22,0 9 54 53-6 4 9 59 i7>2 10 04 53,2 5 6 10 09 22,: 10 19 41 ',6 10 15 08,8 10 24 48,4 7 10 29 28,6 lo 34 58,8 8 ! 10 44 57,6 9 Eclair. 10 54 48,0 lO Eclair. II 04 48,8 III. Colonel Bonne's observations of signals seen from Lignieres. Chronometer Motel, No. 39. Observations du 19 Juillet, le neuvieme jour. Apparition des Signaux, ea tems de la montre. Remarques. 1 i I'Orient. i I'Occident. I h. min. sec. h. min. sec. 2 - 9 44 49*4 3 - 9 54 49'* 4 5. I?: 09 39*4 10 14 50,4 6 7 ^ 10 34 49-8 8 9 10 49 41,0 10, 54 53,2 10 10 59 30,8 11 05 01,0 Observations du 20 Juillet, le dixieme jour. Apparition des Signaux, en tems de la montre. Remarques. 1 4 rorient. i I'Occident. I h. min. sec. h. min. sec. 2 3 9 49 29>6 4 5 10 09 28,0 6 7 8 9 10 49 31,2 10 for determining the difference of meridians , ^c. Colonel Bonne's observations of signals seen from Lignieres. 87 Observations du 21 Juillet, le 11"= jour. I 2 3 4 5 6 7 8 9 10 Apparition des Signaux, en terns de la montre. i I'Orient. h. min. sec. 9 39 24>6 9 49 32>6 10 09 38,8 10 59 33*4 i I'Occident. Remarqnes. h. min. sec. 9 34 50,8 JO 04 53,0 10 34 49,6 10 44 59,4 11 04 51,6 Observations du 2i Juillet, le 12"* jour. Apparition des Signanx, en terns de la moutre. >s Remarqnes. 1 A I'Orient. 1 i. I'Occident. h. min. sec. h. min. sec. I 9 29 16,4 9 34 55'4 3 9 49 2i>8 9 54 53>4 4 5 9 59 I7'0 10 09 21,4 10 04 53, 10 15 08,4 6 10 19 41,8 10 24 48,2 7 10 29 28,2 10 34 58,6 8 - 10 44 57,4 9 10 49 23, 10 54 47,4 10 10 59 25,8 II 04 48,8 IV. Observations of the signals at the Fairlight Station, by Mr. Herschel. By Baker's Chronometer, No. 744. Going M. T. beating half seconds. First Day's Observations, July 11, 1825. No. I 10 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham 9 41 7*6 9 51 3-5 9 56 23-2 10 r 4*8 10 5 59-2 10 II 3'o 10 21 4*4 «o 31 47 10 36 15-8 9 41 6-3 10 46 I2'4 10 51 3'3 II I 8*2 Remarks. Seen, but the time not seized cor- [rectly. The train began at 9^4i'"2*. • Train began at 9'' 20" 59*'5. Seen by the gunners with naked eye Very good. Faint and indistinct. Seen by the Precise. [gunners. Train began at 59*.o. Train began at 58'*5. Very faint. Not seen by the men. Seen by the men. Second Day's Observations, July 12, 1825. No. I 10 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham 9 26 9 36 9 36 9 4» 24-5 7-3 23-3 7'5 9 56 ID I 10 6 10 II 10 16 10 21 10 26 ID 31 10 36 10 41 10 46 10 51 10 56 11 I 17-8 8-8 317 9-2 23*6 lO-Q 22 5 8-0 21-9 8-1 i6-5 5 '4 16-4 6-6 ■ Remarks. Not the true explosion according [to M. Largeteau Very bright and sharp. Lost by looking the wrong way. Distinct. Sharp and bright. Extremely faint. Do\}l)tful. Bright. Distinct. Bright. Seen by Mr. Gilbert with naked Bright. [eye. Train began at i*. ? 1 5 '.5. The decimal correct. Train began at o'.5. Very bright. Train seen 4 or 5'. Train began at o'.5. 88 No. I 9 lo Mr. Herschel's account of a series of observations Mr. Herschel's observations of the signals seen from Fairlight. Third Day, July 13, 1825. La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche 9 31 6-o: 9 51 iz'5 9 56 27*6 10 6 28-5 10 II 16-5 lo 16 i8-i 10 21 14*1 Remarks. A thick sea-fog suddenly came on 2" before the time, though perfectly clear till then. A mere suspicion. Fog thicker, Fog. Fog. Very faint, but distinct. Fog clear- Distinct, [ing Object-glasses examined. All co- vered with moisture from the fog, Well observed. Train seen. Perfectly well seen. Well seen ; but the glass dim, and the fog coming on again. Fog suddenly came on again, and is surprisingly dense, so as scarcely to allow the Mill to be seen ; yet the stars are clear to within 10 degrees of the ho- rizon. Fog. Fog. Fog. Fog. No. I Fourth Day, July 14, 1825. La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham 26 31 36 4» 46 I 6 II 16 10 21 10 26 10 31 10 36 10 41 227 151 15-3 i6'4 28-1 15-2 17-4 15-4 ai-5 196 24-5 i8-8 25-0 15-2 17-5 i8-5 10 46 27-8 10 51 i6-6 La Canche 10 56 197 Wrotham 11 i 17-8 Remarks. Very distinct ; train seen. A pretty strong breeze. Train perfectly well seen. Train seen. Train seen, Wind increasing. ? 23^.5 — am almost sure 2^"'^ is the right. Exploded irregularly at half its height. Train not seen. N. B. A star in the field of the glass. First a bright spark; then the train ; then long after, a feeble explosion at 27'. 8. The first flash was brighter than the ex- plosion. Train feebly seen. Fifth Day, July 15, 1825. No. I 2 10 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche V Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham h. m. s. 9 26 30-4 9 31 22-3 9 36 23-4 9 41 2y2 9 46 24*2 9 56 25*2 ID I i8-o:: 10 6 23*5 10 II 23-4 10 16 i8-i 10 16 25-2 10 21 22'0 10 26 22"5 10 31 25-9 10 36 25-3 10 41 23-3 10 46 25*4 10 51 23-4 10 56 21-5 Remarks. The first flash seen at 19'. 4 on lighting the rocket. The flash at 3o"-4 very bright. Fainter than the i st flash of No. i . A slight flash at lighting. The rocket did not rise. A flash at i6'-3 low down. The flash at 24*'2 higher, and to the right of the former. (The teles- cope inverts. N. B.) Faint, but very distinct. r Signal regular and distinct, but I observation uncertain from a I violent noise in the adjoining L field. ^ Sharp and good, but low. Feeble and high, to the right of the former. {Certainly 'o, but the second un- certain, from a violent noise which drowned the beat of the watch. {Noise continued, and the ob- servations uncertain on ac- count of it. Single explosion ; well observed. Well observed. Single explosion ; extremely f. Well observed. The train seen. No explosion. The signal not repeated. Sixth Day, July 16, 1825. No. I 4 5 6 7 8 9 10 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham h. m. s. 9 26 26'3 9 3' 3»-4 9 36 i9*» 24-3 9 41 30*0 9 46 38-0 9 51 26'I 10 I 31*6 10 21 10 26 lo 31 10 36 ID 41 io 46 ID 51 10 56 11 I 30-8 32*2 327 21-5 291 27*2 35-9 i8-2 299 296 297 Remarks. Extremely faint. The decimal correct, the second possibly erroneous from noise. Small bright spark. Broad feeble flash, higher, and to the apparent right Exact on the beat. Single bright flash. Explosion distinct but unex pected, as it happened before the rocket reached its greatest elevation. Regular, and well observed. Regular, and well observed. Bright single flash. Excessively faint. Extremely faint. Very bright. Very bright. Observed with M. Largeteau's glass ; a doubt having arisen as to its correct pointing, he having seen none of the La Canche signals this even- ing- for determining the difference of meridians, &c. Mr. Herschel's observations of the signals seen from Fairlight. S9 Seventh Day, July 17, 1825. La Canche h. m. 8. 9 26 20-6 Wrotham 9 3» 36-3 La Canche 9 36 20'5 Wrotham 9 41 35'9 La Canche 9 46 27-0 Wrotham 9 51 37-2 La Canche 9 56 28*0 Wrotham 10 1 37-6 La Canche 10 6 28*2 Wrotham 10 II 35*7 La Canche 10 16 29-5 Wrotham 10 21 38-9 La Canche 10 26 27-8 Wrotham 10 31 41-0 La Canche 10 36 24-5 Wrotham 10 41 41-1 La Canche 10 46 38-5 Wrotham 10 51 317 La Canche 10 56 302 Wrotham II I 38-7 Remarks. Excessively faint but instantane [ous. : : A mere suspicion. Well observed. Telescope put in focus by a *. Extr. faint, like a * of 10 m. Exactly observed. Very distinct ; perfectly well ob- [served : : A pretty strong suspicion. The second doubtful, owing to the lateness of the explosion. : : : A faint suspicion. Ninth Day, July 19, 1825. No. b. m. s. Remarks. I La Canche 9 26 31-3 or 3 4' 3, certainly one or the other. Wrotham 9 31 51-5 Very brilliant. La Canche 9 36 33 0 Very bright ; well observed. Wrotham 9 42 0-5 Remained extremely long in the air, & mounted to a vast height. La Canche 9 46 338 3 Wrotham 9 5^ 53*8 La Canche 9 56 29-1 4 Wrotham 10 1 56-4 La Canche Missed by looking into the wrong 5 telescope by mistake. Wrotham 10 II 51*1 Burst without rising. La Canche 10 16 32-2 Train seen before the flash. 6 TTwo rockets fired. The first Wrotham 10 22 2*5 < burst, the second observed as ( here set down. La Canche 10 26 337 Train seen as well as flash. 7 Wrotham 10 32 248 La Canche 10 36 35'o Extremely faint; the train as g bright as the flash. Wrotham 10 41 597 Very bright. La Canche 10 46 37-6 Train seen. 9 Wrotham 10 51 59-8 Mounted to an immense height. La Canche 10 56 29*5 The first flash at lighting ob- served; a second flash a long while after, seen, but time not taken. Wrotham 11 I 51*0 First flash, rocket burst. 2 3-5 Second rocket, rose regularly. No. I 2 3 4 5 6 7 8 Eighth Day, July 18, 1825. No. b. m. tec. La Canche Wrotham Remarks. I 9 31 4>'9 Good. La Canche 9 36 30'9 Good. Wrotham 9 41 46*0 Good. 3 La Canche 9 46 297 Good. Wrotham 9 5» 49-5 Good. ^ La Canche 9 56 328 Good. 4 Wrotham 10 I 50-3 Good. La Canche 10 631-4 Good. S Wrotham 10 II 486 Good. Uncommonly bright. 6 La Canche 10 16 32*3 Good. Wrotham 10 21 47-0 Good. 7 La Canche 10 26 23*4 Unexpected ; possibly i* wrong. Wrotham 10 31 42*8 Good. La Canche Wrotham 8 10 41 47*2 La Canche 10 4& 27*0 : : 111 observed. 9 Wrotham 10 51 431 10 La Canche ic 56 24*9 Perfectly well observed. Wrotham II I 420 Tenth Day, July 20, 1825. La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canehe Wrotham La Canche Wrotham La Canche Wrotham 9 3' 43'3^^ 9 36 36-2 9 41 58-0 9 4^ 37-9 9 51 56-0 10 I 567 10 6 44*1 10 1 1 57-9 Remarks. Single flash. Single p. bright flash. Single flash ; train not seen. 10 22 4*4 10 31 58-1 10 41 58-0 10 51 58-0 II 1 58-5 ! A second fired, but both were bad signals. Observation of little value. Large flash ; some seconds after a small faint one. MDCCCXXVI. N 90 No. I 2 3 4 5 6 Afr. Herschel's account of a series of observations Mr. Herscuel' spb^ervations. of the signals seen at Fairlight. Eleventh Day, July 21, 1825. La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham 9 36 9 42 9 46 9 52 9 56 10 2 10 6 10 12 10 16 10 22 10 26 10 — 32 10 36 10 42 10 46 10 52 10 56 1 1 2 36-1 I 77 39-0 2-5 3-0 3-5 41-5 27 8-0 39-8 i-o 8-9 377 8-8 28-3 8-4 47*9 1*1 2*0 41-9 2-5 22'0 41-1 I'O Remarks. A most favourable night, and transparent atmosphere. Three rockets fired, but all burst, and none could be observed. Good. The rocket rose regularly. Excellent. /Three rockets fired in close 4 succession, all burst. or I ' > Both burst without rising, Twelfth Day, July 22, 1825. 7 Both well observed, but both I burst without rising. Excessively feeble, but certain. [ Both burst without rising. Two fired; the first missed; both burst. Very good; train seen; the rocket remained very long in the air. I Both burst. > Both burst. One only, which burst ; being the 19th out of 20 fired to night. , No. I 2 3 4 5 6 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham 26 35-5 32 9*o 36 39'^ 42 7-0 46 42-5 52 8-6 56 42-5 2 101 6 58-0 12 07 10 26 48-2 10 32 3-0 8-9 10 26 48-2 47-c 58-8 :o 36{+7-° 10 42-! 7-2 10 46 36-9 ( 2*0 '° 52 I 87 11 2 2*8 Remarks. Very bright and fine. Regular and good. Train well seen. Regular and well observed. Train seen. Rose to a vast height Regular and well observed. Very good. Perfect observation. Very exact. Burst without rising. Two fired ; both burst. Both burst. Rose regularly, but rather a doubtful observation. All three burst. Single. Train seen. ' Both burst. :: Doubtful. Burst. V. Copie des Observations a Fairlight Down par C. L. Largeteau. 1825. (Baker's Chronometer, N**. 744.) 1 2 Juillet. No. h. m. sec. Remarks. I La Canche 9 36 229 Wrotham T.a CanrVip 9 41 7-9 3 Wrotham La Canche 9 51 7'o 9 56 17-8 4 Wrotham La Canche 10 I 8-6 10 6 317 5 Wrotham 10 II 9-4 6 La Canche 10 16 23-8 Wrotham 10 21 lO'O La Canche 10 26 22-5 7 Wrotham 10 31 79 8 La Canche ID 36 21-9 Wrotham 10 41 83 La Canche 10 46 165 9 Wrotham La Canche 10 51 5'i 10 56 15-9 Wrotham il I 117 il faut peut etre ii** I"" 6.7s 1 3 Juillet. No. I 3 4 5 6 7 8 9 10 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham b. tn. 8. 9 56 27-3 10 6 28*5 10 II 14*6 10 16 17-9 10 21 14-0 Remarks. for detennining the difference of meridians y ^c. M. Largeteau's Observations at Fairlight continued. 91 No. I 2 3 4 5 6 7 8 9 lo 14 Juillet. La Canche Wroth am La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham h. m. 8. 9 26 227 9 31 15-3 9 41 i6-6 9 46 280 9 5' 15-0 9 5^ 17-4 10 1 19-4 10 6 21-8 10 II 19.5 10 16 23.6 10 21 18-9 10 26 25-0 10 31 15-3 10 41 i8-5 10 46 27-8 10 51 16-4 10 56 20-0 II I 17-9 Remarques. 15 Juillet. I 2 3 4 5 6 7 8 9 10 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham 9 3» 224 9 4» 23'o 9 46 24-8 ic II 23*4 10 21 22-5 lo 31 25-4 10 36 25.3 10 41 23-3 10 46 25*3 10 51 23*2 Remarques. I 2 3 4 S 6 7 8 9 10 16 Juillet. La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham b. HI. s. 1 9 31 3»-3 9 41 29-9 9 51 25-8 10 I 31*5 10 II 307 10 21 32*6 10 31 28-9 10 41 3S'3 10 51 10 56 11 I 30-0 297 29.8 Remarques. 17 Juillet. I 2 3 4 5 6 7 8 9 10 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Cancbe Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham b. m. a. 9 26 20-8 9 31 36-0 9 36 20*3 9 41 35*9 9 51 37-0 9 56 277 10 I 37-4 10 6 27-9 10 II 3S-6 10 21 38-8 10 26 277 10 3> 407 10 36 248 10 4» 40-8 10 46 38-5 1 10 SI 32-0 II 1 38-4 Remarques. Faible. Faible. Faible. Faible. 92 Mr. Herschel's account of a series of observations M. Largeteau's Observations at Fairlight continued. 1 8 Juillet. I 2 3 4 5 6 7 8 9 lO La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham h- m. e. 1 9 36 3ro 9 41 46-4 9 46 29-8 9 5» 497 9 5t> 32-5 10 16 32-2 lO 21 46-8 lO 26 24-5 lO 31 42-5 lO 4' 47 '2 lO 46 30-3 lo 51 43 -o lO 56 25-0 II I 42-4 Remarques. Faible. Faible, Observation douteuse Observation douteuse Observation douteuse 19 Juillet. I 2 3 4 5 6 7 8 9 10 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham 31 36 42 46 51 I 50-5 33.2 o'4 33-5 53-5 288 56-6 Remarques. Observation douteuse 10 II 50*5 10 16 32*5 10 22 2-4 10 26 337 10 32 247 10 36 35-1 10 41 46 10 10 51 59-9 37'5 59-4 II 2 3-3 Observation douteuse ou 14.7. Extremement faible. No. 1 2 3 4 5 6 7 8 9 10 20 Juillet. 9 31 43-5 9 41 58-2 9 51 56-4 10 1 56-5 La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham 10 31 577 La Canche Wrotham 10 41 58*3 La Canche Wrotham La Canche Wrotham 10 II 57-5 10 22 4*5 10 51 57 9 Remarques, incertajne. incertaine. No. I 3 4 5 6 7 10 21 Juillet. La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham La Canche Wrotham 9 36 36*0 9 42 7"6 9 46 389 6 39-8 12 o*4 26 38-2 32 1-9 8^ 36 47'9 42 0-9 10 46 41-8 10 52 2-3 21-5 ri Remarques. Faible. i'^'"^ Explosion. 2e i^'^* Explosion. I'""* Explosion. 2e i*""^ Explosion 2* for determining the difference of meridians, &e. 93 M. Largeteau's observations at Fairlight continued. 22 Juillet. No. b. m. 8. Remarques. La Canche 9 26 35-3 Wrotham 9 32 8-9 La Canche 9 36 39-8 Wrotham 9 42 6-9 La Canche 9 46 42-4 3 Wrotham La Canche 9 52 «-5 4 Wrotham 10 2 97 La Canche 10 6 V7 5 Wrotham 10 12 07 Douteuse La Canche 10 16 377 6 r 1-8 i«'* Explosion 1 Wrotham 10 22< 8-0 2^ lobs, incertaine. 3" J La Canche 10 26 47 9 7 Wrotham 10 32 1 27 9-1 I- Explosion |p^^.^^^^^^^ 8 La Canche 10 36 (;9-o Douteuse, Wrotham La Canche 10 46 ^7*4 9 Wrotham La Canche 10 56 37-8 Tres douteuse. Wrotham II 2 27 VI. Observations made at the top of the Royal Observatory, Greenwich, on the rockets at PFrotham. July 11, 1825. The blue light and all the rockets were this evening distinctly seen by the naked eye. The observations were made with telescopes, by three observers, with the same chronometer. The chronometer was compared with the transit clock both before and after observation. The blue light appeared about 9^ 21°* 25'. Rockets. I 2 3 4 5 6 7 8 9 10 App* Time I. 9^310.54.48 9 41 4925 9 SI 4575 10 I 47.5 10 21 46.75 10 31 46.8 10 51 45.8 11 I 50.4 - IL 54.3' 49.4 46.2 47.8 45.8 47-1 47.2 490 46.3 50.5 - III. - - 54.28 - - 49-2 - - 45-8 - - 47-4 - - 45-4 Absent. - - 47-3 - - 48.4 - - 46.2 - - 50.6 Mean* 54-30* 49.28 45.92 47.56 45.60 46.92 47.10 48.70 46 10 50.50 Chronometer Clock. Comparison before - - gh ^^.m 16'' 12"" 22».o6 after - - II 14 18 31 44.67 *» Mean Error and Rate of Sidereal Clock. Mean of transits of 5 * ' I Corresponding mean error. Rate. i6'» 24m I 48.36' — 0.02 Chronometer fast i" 17.97*. The loss of the fifth observation in column I , was occasioned by some accidental derangement of the telescope. The loss of the eighth was occasioned by the rocket passing through the field of view before explosion. Observations 9 and jo, in column i, were made with the naked eye. • In taking the mean of the three observations, those marked (: : ) doubtful, are not considered. *• The transit observations employed throughout are reduced by the same system of corrections, and mean right ascensions, as those used at the observatory of Paris for that purpose ; so that no error in the results, from a difference of catalogues or corrections, is introduced. 94 . Mr. Herschel's account of a series of observations July 12. All the signals, the blue light excepted, were this evening visible to the naked eye ; the blue light could not be seen at all :* the times of the explosions w^ere this even- ing all observed with telescopes. Rockets. App* Time. I II. Mean. : I 2 3 4 5 : 6 7 8 9 lO 9631 50' 41 50.75 51 50.0 10 1 51.5 II 51.8 21 53.0 31 51.0 41 51.2 51 48.0 11 I 49.8 9»'3i'"49.8» 41 50.6 51 50.0 10 I 51.S II 52.2 21 52.8 31 51.0 41 51-3 51 48.0 11 I 49.7 o o a bo G 49.90" 50.67 50.00 51.50 52.00 52.90 51.00 51.25 48.C0 4975 Chronometer. Comparison before After 9" 11° II 12 Clock. 16* 32" 19.94' »8 33 39'8o Mean Error and Rate of Transit Clock. Mean of 5 • ' I Corresponding error. I Rate. 16" 24"" I 48.27* I —0.08 From mean comparison on nth, to ditto on 12th, chronometer gained 1.02'. Chronometer fast i" 18.99'. Rockets I and 6 exploded twice, at an interval of about three seconds. The first explosion, in each case, was the one observed ; the second, not being expected, was lost. • None was fired. (H.) for determining the difference of meridians , &c. 95 July 13th. All the signals were visible to the naked eye. Rockets. App' Time I. II. III. Mean. I 2 3 4 S 6 7 8 9 10 9" 31-55.8' 9 51 55-75 10 I 55.0 II 57.4 21 57.2 31 56.6 41 56.0 51 55.8 9^31- 55.6 » 51 56.0 10 I 55.2 " 57-3 21 57.0 31 56.6 41 56.0 51 55.6 11 I 56.2 55.6' 55.2 S4.8 57.6 57.0 56.5 5S.8 55.3 56.2 55.67. 55-87 55.0 57-43 57-07 56-57 55-93 55-57 56.2 Comparison. Before - After - Chronometer. 9'' 16" II 13 16'' 41" 16.63' 18 38 35-75 Mean Error and Rate of Sidereal Clock. Mean of 6 * » 16'' 40" Mean error corresponding. 48-39' Mean rate. + 0.14 Comparison 12th to ditto 13th. Chronometer, + 0.87. Chronometer fast 1° 19.86*. The 2d rocket was lost by all the observers : it did not appear till some seconds after the time specified; and when it did appear it exploded immediately. It exploded about 9'' 42" 22*. The loth rocket in column I. was lost by a derangement of the telescope. The third observation, column III. is doubtful to half a second. 96 Mr. Herschel's account of a series of observations July 14. Rockets. I 2 3 4 5 6 7 8 9 ID App* Time I. 9" 31' 42 51 10 I 12 22 31 42 52 2 II >59.o» 0.7 59.0 58.8 3-4 3-2 59-4 2.4 0.3 1.8 II. 59.2" 0.4 59.0 59-4 3-3 31 59.2 2-3 0.5 2.0 III. Mean. 59.10- 0.55 59.00 59.40 3-35 3-15 59-30 2.35 0.5 1.9 Comparison of Chronometer and Clock. Chronometer Before After II" 15 Clock. i6'»40"' 11.87' 18 44 32.13 Mean Error, and Rate of Sidereal Clock. Mean of 7 * ' Mean error corresponding. i6»'2i'» 48.25' Mean rate. — 0.16 Comparison 13th to ditto 14th + 0.38. Chronometer fast i" 20.24". July 15th. The third, fourth, and last rockets disappeared without any explosion. In the third column something like an explosion was noted at the beginning of the ascent of the third rocket, but no dependance can be placed on it. Rockets. App* Time. I. II. - III. Mean. I 2 3 4 1 7 8 9 10 9>»32'" 8.68 42 8.8 - - 8.5. - - 8.4s 8.5' 8.93 9.20 8.03 II. 2 9-23 9.07 - - 9.0 - - 9-0 ::lo 2 3.0 - - 9.2 - - 8.0 10 12 9.4 22 8.1 32 10.9 42 9-3 52 9.2 - - 9.0 - - 8.0 - - II. 2 - - 9.2 - - - 9.0 - - 11.5 - - 9.2 - - 9.0 Comparison of Chronometer and Clock. Chronometer. Before After 91*24" II 10 Clock. i6'>5^'° 9.80' 18 43 27.04 Mean of 6 • " iGh o Mean Error, and Rate of Sidereal Clock. Mean error corresponding. 47.92- Mean rate. — 0.30 Comparison 14th to ditto 15th + 0.47 Chronometer fast i" 20.71s. for determining the difference of meridia?is, &c, 97 July 16. The third rocket disappeared without explosion. ckets. App*Time. I. I 9'»32°'i7.os 2 3 4 42 15.6 10 2 16.8 5 12 16.4 6 22 18.0 7 32 14.9 8 42 21.0 9 52 15.8 10 II 2 15.2 II. III. Mean. 16.9s 15.6 17.2 16.3 17.9 14.8 21.0 15.2 15.1 16.98 i6.93« 15.4 15-53 17.1 17.03 I6.S 16.40 18.3 18.07 I5.I 14-93 21.0 21.0 15.4 »5.47 155 15.27 Comparison of Chronometer and Clock. -- Chronometer. Before 9^18"' After II 12 Clock. i6'» 55" 5.29s 18 49 24.06 Mean Error and Rate of Sidereal Clo Mean of 5 * » Mean error corresponding. 16.6 47.60* ck. Mean rate. - o.33« Comparison from 15th to i6th — 0.31. Chronometer fast i" 20,408. MDCCCXXVI. o 98 Mr, Herschel's account of a series of observations July 17th. The loss of observation 1, in columns I. and III. was occasioned by the observers mistaking the mi- nute. It was however very accurately taken by the second observer. Rockets. App* Time I. II. - III. Mean. I 9'' 32" 20.18 20. i» 2 9*42'"20.0» 42 19.9 :: _fc _•» ip.18 19.95 3 52 20.8 - - 21.3 - - 21.3 21.13 4 10 2 21.4 - - 21.4 - - 21.4 21.40 5 12 19.8 - - >9-3 - - 19-2 1943 6 22 22.9 - - 22.8 - - 22.9 22.87 7 32 24.8 - - 24.8 - - 24.8 24.8 8 42 25.0 - - 25.0 - - 25.0 25.0 9 - - :: 10 52 16.0 — 10 II 2 22.5 - - 22.6 - - 22.6 22.57 Comparison of Chronometer and Clock. Chronometer. Before 9'* 21°' After II 11 Clock. 17' 3.68* 18 52 21.72 Mean Error and Rate of Sidereal Clock. Mean of 7 ♦ s j Mean error. 15" 30° 47-56' Mean rate. — 0.06 Comparison from 16th to 17th — 1.40. Chronometer fast i*" 19.008 The ninth rocket exploded the moment it began to ascend; the time noted cannot be depended on. for determining the djffereyice of meridians, &c. 99 July 18th. The first, seventh, ninth, and tenth rockets could not be observed ; one or tv^^o exploded without ascend- ing ; the remainder did not explode at all. Rockets. App' Time I. II. - III. Mean. I — 2 p** 42" 29. IS - - 29.0' - - 29.1' 29-07' 3 - 52 32-1 - - 32.3 - - 32.2 32.20 4 lO 2 33.3 - - 33-0 - - 33-2 33-»7 5 - 12 31.1 - - 31.0 - - 31.6 31-23 6 - 22 29.8 - - 29.6 - - 29.7 29.70 7 — 8 - 42 29.9 - - 30.0 - - 29.9 29.93 9 — 10 — Comparison of Chronometer and Clock. Chronometer. Before 9* 37" After II II Clock. i7>»22°' 3.55' 18 56 18 95 Mean Error and Rate of Sidereal Clock. Mean of 6 ♦* i6''o° Mean error. 47- 30* Mean rate. — 0.26* Comparison from the 17th to i8th — 0.93. Chronometer fast i" 18.07'. 100 Mr. Herschel's account of a series of observations July 19th. The fifth rocket could not be observed. Rockets. App* Time I. II. - III. Mean. I 2 3 4 5 6 7 8 9 10 9i»32»43.i' - 42 41.0 - 52 34-1 10 2 36.9 - 22 42.9 - 33 4.8 - 42 40.1 - 52 40.0 ::ii 2 43.3 - - 43 -o" - - 40.9 - - 43-0" - - 41.0 43^03" 40.97 34-13 36.9 42.9 4^75 40.1 39^97 43^7 - - 34-1 - - 36.9 - - 4^-9 - - 40.0 - - 40.0 :: -43.1 - - 34-2 - - 36-9 - - 42.9 - - 4-7 - - 40.2 - - 39-9 - -43-7 Comparison of Chronometer and Clock. Chronometer. Before 8" 48-" After II 10 Clock. 16*" 36"" 53.84' 18 59 17.02 Mean Error and Rate of Sidereal Clock. Mean of 3*' I Mean error. | Mean rate. 1 6*' 50"" 47.i6« — 0.19* Comparison from i8th to 19th — 1.81 Chronometer fast x™ 16.268 Observation 10 in columns i and 2 doubtful to half a second. for determining the difference of meridians , &c. lois. July 20. The rockets this evening were miserably bad; five only were observed ; the eighth however might have been a good one ; it was lost by all the observers looking: for it too late. Rockets. App' Time I. - - - n. - - - III. Mean. I 2 3 4 5 6 7 8 9 < ^h j2>n 36.6s 52 56.2 10 22 45-7 36.73 - - 56.0 - - 45-8 10 32 53.0 36.93 - -56.1 10 12 39.2 - 22 46.1 - - 53-> 36.73' 56.1 39-2 45-87 53-05 lO Comparisons of Chronometer and Clock. Chronometer. Clock. Before 9'' 6" le** 58" 53.06s After II 10 1 19 3 »3-34 Mean Error and Rate of Sidereal Clock. Mean of 5 • ^ I Mean error. I Mean rate iji* 40" 47.228 -^0.03" Comparison from 19th to 20th, + 0.35 Chronometer fast i"* 16.618 102 Mr. Herschel's account of a series of observations July 21. The rockets much worse this evening than they were last. Only one out of the whole number mounted at all. All the others were seen, but nothing was sufficiently definite to admit of being noted. * Rockets 1 2 3 4 S 6 7 8 9 lO App* Time I 9'' 42'" 48.88 II. 48.8' - III. - - 48.8' Mean. 48.8» Comparisons of Chronometer and Clock. Clock. !»» 9n> 50.88* Chronometer. Before 9'' 13"" After II 10 19 7 9.93 Mean Error and Rate of Sidereal Clock. I •». Error. Rate. i;"* 26"". 47-37 + 0.20' Comparisons from 20 to 21, +1.02 Chronometer fast i™ 17.63' * It is much to be regretted that some attempt at least to note them was not made. Had it been done, this night's result, which is now dependent on a single signal, might perhaps (as they were for the most part tolerably well observed at Wrotham), have been placed nearly on the same footing with the rest. H.) X for determining the difference of meridians y ^c. 103 July 22. Rockets extremely bad ; four only could be observed. Rockets. App»Time I. - - - II. - - - III. Mean. I 2 3 4 1 7 9»'32'" 51. 2S - 42 49-9 - 52 51-4 51-35' - - 49.8 - - 5'-3 10 2 52.4 5i.4« 49.6 51-3 - - 52-4 51.32. 49-77 5«-33 52.4 8 9 10 — Comparisons of Chronometer and Clock. Chronometer. Clock. Before 9* 23" I 17^ 23™ 48* After II II 19 12 5.59 Mean Error and Rate of Sidereal Clock. Mean of 5*'. 15^ 47^ Mean error. 47-57' Mean rate. + 0.21 Comparisons from 21 to 22, + 0.32. Chronometer fast 1™ 17.95* The means of the Comparisons, with the true Sidereal Time corresponding. July II 12 »3 H 15 16 17 18 19 20 21 22 Chron. lo'^4m 30' 10 II 30 ID 14 30 10 15 O ID 17 10 15 10 16 10 24 9 59 10 8 10 II 10 17 o o o o o o 30 o Clock. 171122™ 3.36* 17 32 59.87 17 39 56.19 17 42 22.00 17 50 18.42 17 52 14.67 17 57 12.70 18 9 11.25 17 48 18 I 5-43 3.20 18 8 30.405 18 17 56.79 True Sidereal Time. 7'»2i™ i5.o» 7 32 11.60 39 41 49 5» 56 8 47 o 7 17 7.80 33-75 30.52 27.09 25.14 23-97 18.27 15.98 42.03 9.20 104 Mr. Herschel's account of a series of observations True Sidereal Time of the explosions. r July II. Rockets. I 2 3 4 5 6 7 8 9 lo True Time. i6''48^ -58 17 18 8 18 28 38 48 58 8 18 13.3928 30.54 28.82 32.11 31-79 34.85 36.56 39.80 38.84 44.8 July 12. Rockets. I 2 3 4 5 6 7 8 9 10 True Time. 16^52™ 24.98s 17 2 27.38 28.27 31.51 33.66 36.21 35.93 37.82 36.19 39-59 18 12 22 32 42 52 2 12 22 July 13. Rockets. I 2 3 4 5 6 7 8 9 10 True Time. i6'> 56" 26.45= 17 18 16 26 36 46 56 6 16 26 29.95 30.73 34.81 36.09 37.33 38.23 39.50 41.77 July 14. July 15 July 16. Rockets. True Time. Rockets. True Time. Rockets. True Time. I lyh Qin 26. 1 OS I 17'' 4'n 31.64* I lyh gm 37.06* 2 — 10 29.20 2 — 14 33.72 2 — 18 37.34 3 20 29.30 3 3 4 — 30 31.34 4 4 — 38 42.03 5 — 40 36.94 5 — 44 39.04 5 — 48 43.04 6 - 50 38.39 6 — 54 39-39 6 — 58 46-36 7 18 0 36.00 7 18 4 44.21 7 18 8 44.95 8 — 10 40.87 8 — 14 43.88 8 — 18 52.58 9 — 20 40.66 9 — 24 45.35 9 — 28 48.68 10 — 30 43.71 10 10 — 38 50.12 July 17. July 18. July 19. Rockets. True Time. Rockets. True Time. Rockets. True Time. I i7'»i2ro 38.098 I I 17** 20"* 56.91* 2 — 22 39.58 2 I7h jgm 46.25' 2 — 30 56.55 3 — 32 44.40 3 — 36 51.02 3 — 40 51.34 4 — 42 44.30 4 — 46 53.62 4 — 50 55.77 5 — 52 43-96 5 — 56 53.31 5 6 18 2 49.06 6 18 6 53.42 6 18 II 5.09 7 — 12 52.63 7 7 — - 21 28.65 8 — 22 52.48 8 18 26 57.05 8 - 31 5.58 9 10 — 42 55.29 9 10 9 - 41 7.1 1 — 51 12.50 10 July 20. Rockets. True Time. July 21. Rockets. True Time. July 22. Rockets. True Time. 1 2 3 4 5 6 7 8 9 10 1 7'' 24"! 46.90* 17 45 9.60 18 4 55.95 — 15 4.28 — 25 13.12 I 2 3 4 5 6 7 8 9 10 I7*»38m 56.10* I 2 3 4 S 6 7 8 9 10 1 I 7^32°' 53.27* - 42 53.36 - 52 56.56 8 2 59.28 for determining the difference of meridians, ^c. 105 Statement of the method of combining and calculating the Obser- vations, and obtaining the Rates of the chronometers. Previous to stating the result of these observations, it will not be irrelevant to explain the method pursued in reducing them, and the principles on which the calculation has been made ; and it may be here remarked, that the brevity and facility of the computations which will appear to be required for this purpose, is not the least recommendation of the method itself. Suppose A and Z to be the two extreme points whose difference of longitudes is to be determined, and at each of which the true sidereal time is supposed to be known by transits of well determined stars and registered by exact clocks, or carefully compared chronometers. Intermediate between these, suppose two, or any number of stations, B, C, &c. chosen, at each of which are placed observers fur- nished with telescopes and good chronometers ; and again, intermediate between these, and in the order A, a, B, 6, C, c, Z, let posts or stations a, b, c, be selected, at which signals are made, by the explosion of gunpowder, the discharge of rockets, the extinction of lamps, or otherwise, at regular concerted times, and so arranged that the signals at a shall be visible from both A and B ; those at b from both B and C ; and those at c from B and Z. Now let a signal be made at a, and observed both from A and B, and the moment of its happening noted at A by the sidereal clock, and at B by the MDCCCXXVI. P 106 Mr, Herschel's account of a series of observations chronometer ; then, if the observations were perfect, the difference of the clock at A, and the chronometer at B, would become exactly known. Let this be denoted by A — B. A short time after, let a signal be made at 6, and observed by the chronometers at B and C, whose difference (which we will in like manner denote by B — C,) becomes thus precisely known at the time of making the signal. In the same manner may the difference C — Z of the chronometer at C and the sidereal clock at Z be known at the moment of explosion of a signal at c ; and so on, if there be more intermediate stations. Now, the clocks at A and Z being all along supposed to keep strict sidereal time, if the watches at B, C, did the same, it is manifest that the difference between any two of them determined at one moment would be the same at every other ; and therefore the intervals elapsed between the signals would be out of the question, and the observations might all be regarded as simultaneous ; so that the sum of the differences (A — B) + (B — C)+ (C — -Z) =A — Z would express strictly the difference of the true sidereal times at the extreme points, /. e, their difference of longitudes ex- pressed in time, without any further calculation or reduction. It is equally evident that, whatever be the rates of the watches, if the intervals elapsed between the signals were infinitely small, so as to reduce their gain or loss in these times to nothing, the same would hold good. Since this however cannot be the case, it is obvious that the difference of longitudes so obtained will be affected by the rates of the watches and the intervals of the signals, which must accord- for determining the difference of meridians ^ &c. 107 ingly be allowed for. Now, as the intervals at which the signals are made at the successive stations are small (only five minutes), the gain or loss of the watches used may be calculated for such small times to great nicety ; and, if the watches were regulated to sidereal time, and of any ordinary degree of goodness, the correction on this account would be almost insensible ; or, if regulated, as is generally the case, to mean time, the reduction from mean to sidereal time only need be applied, neglecting the deviation of the rates from strict mean time. The calculation then becomes of extreme simplicity ; for since the watches have equal rates, we have no occasion to apply aiiy correction to their observed dif- ferences ; and it will suffice to apply to the uncorrected value of A (= A — Z, or) ^^ (A —B) + (B' — C) + (C - Z") the mere reduction from mean to sidereal time for the in- terval elapsed between the first and last signal ; or in other words (regarding the whole operation as a species of tele- graphing), for the time the message has occupied in its trans- mission from one observatory to the other.* For example. On the 19th, a signal was made at Mont Javoult, and noted at Paris to have happened at 18^ 39"" 5^' -5 true sidereal time at Paris, and at Lignieres at 10^ 49°* 4i'.o by the Lignieres Chronometer. About 5°* after this, a signal made at La Canche was observed at Lignieres to happen at .10" 54° 53'-s, and at Fairlight at 10^ 46" sT-S by the Fair- light chronometer. Finally, a third signal was made about 5" later still at Wrotham, and observed at 10^ 51°" 59^.4 by • Might not telegraphs be employed to ascertain the difference of longitudes of the stations between which they are established ? 108 Mr. Herschel's account of a series of observations the Fairlight chronometer, and at 18^ 41"" 7M1 true sidereal time at Greenwich. The calculation then stands thus + A = +i8 39 52 '50. — B = — 10 4941-00 + B'=+io 54 53-20 — €'=— 10 4637-50 + C"=+io 51 59-40 — Z"=:— 18 41 7-11 B' — B rz + o 5 i2'2o C"— C'= + o 5 21-90 Sum o 10 34-10 Sum = +38" i44°i65s-io —^S^ i36"858.6i r: o'' 8° 79*-49 or rso" 9" 198.49 the uncorrected value of A Reduction from mean to ^ Sid. T. for an interval y= + 1*73 of io"» 34»-io . . J — — — — o 9 21-22 r= A the corrected difference of longitudes. Such is the result of the transmission of a single signal along the line, and such the whole calculation required to deduce it. It is chosen at random from among the observa- tions, yet is probably entitled to at least as much confidence as any value hitherto previously obtained ; a circumstance which sets the excellence of this method in a very strong light. Such would be the process of calculation in the simplest state of the data, viz. when the signals are seen along the whole line without a failure, so that each message so trans- mitted arrives at its destination and gives a complete result. But this (in the present instance at least) has not been always, or'generally the case. It has much more commonly happened that a signal made at one station (a for instance, has not been simultaneously observed, or not observed at all, at A and at B, while the other signals, at 6, c, &c. have been regularly seen and registered. In every such case (of which endless combi- nations may occur) a link of the chain fails, and no result can be obtained from this series of observations taken singly. A very slight consideration will suffice to show that were we for determining the difference of meridians , &c, 109 to reject all such broken series, the observations of a whole night might easily be thrown away, though capable of affording a result quite as good as any other. Such a case actually occurs in the observations of the 18th, where no complete transmission of any one signal from end to end of the line took place, yet the mean result of that night's obser- vations deviates less than two-tenths of a second from the result finally adopted as the truth. The most advantageous way of employing such a broken series of observations as we have described is not at once obvious. It may depend on circumstances too nice for cal- culation, and which can be felt only by the observers them- selves. The fairest however, and that which by employing all the observations according to one uniform rule leaves nothing to partiality, seems to me to be the following. Let A be the time marked by the sidereal clock at the first extreme station A, then calling E the time marked by the same clock at any assumed arbitrary epoch, A — E will denote the sidereal time elapsed since that epoch. Call j3 the rate or sidereal time of the chronometer at the 2d station (B), /3 being supposed negative when the chronometer loses, (as for instance when it shows mean time). At the same moment that the clock at A marks A, let this chronometer mark B, then, since /3(A — E) is the quantity it has gained, since the epochs, B — jG (A — E) must be the time it would have indi- cated, if instead of gaining or losing, it had kept true sidereal time since the epoch. Consequently (the clock being sup- posed to have no rate) A— | B— /3 (A— E) jor A— B+ iQ(A-E) will be the difference of the clock and chronometer reduced jio Mr. Herschel's account of a series of observations to this epoch, i. e. the difFerence they would have indicated if instead of comparing them at the time A, they had been compared at the time E. Every signal simultaneously observed at A and B, gives a direct comparison of the clock and chronometer ; but it is only when thus reduced to a fixed epoch that these compa- risons become comparable inter se ; but when so reduced their mean may be taken, and is of course preferable to the fesult of any single comparison. Hence if we put P = mean of all the ( A — B) + /3 x mean of all the (A - E) P will express the difference of the clock and chronometer at the epoch more probably than any of the individual values derived from single observations. It follows therefore that at any other sidereal time A', the time indicated by the chronometer at B, (or B') may be cal- culated from the expression B'= (A'^P) + /3 (A'— E) (a) more probably than it can be derived from any single actual observation. This equation gives A'= ^^^^j^=^ = B' -f P — ^ (P + B' — E) neglecting squares and higher powers of jS, whence the time by the clock at A becomes known at any instant in terms of that shown by the watch at B. Now let a signal be made between B and C, and noted to happen at the moment marked B' by the watch at B, and C by that at C. Let )3 and y denote their respective rates on sidereal time ; then since B' — jS (A'— E) and C— y (A'— -E) are the times they would have marked had they kept strict for determining the difference of meridians , &c. iii sidereal time since the epoch, their difference reduced to the fixed epoch will be (B'— C')-(;3-y)(A'_E) in which, substituting for A its value above found, we get (B'_C')-(/3-y)(P + B'-E) neglecting powers and products of jS and y. Putting then Q=:mean of all the{B*-- C)-(3'-r/)—meanofall the (P+B'— E) we get the most probable value of the difference of the chronometers at the epoch which can be obtained from any number of such comparisons. Finally, if we make a comparison at any time A" (Paris Sid. T. ) between the watch at C and the clock at z, and call their indications at that moment C" and Z", their apparent difference will beC — Z", and their difference reduced to the epoch will be (C— Z") — y(A'— E). But Q being the most probable difference between the chro- nometers B and C at the epoch, and (jS — y) the difference of their rates Q + i^-Y){A"-E) will be their difference at any other moment A"; hence B''-~ C'= Q + (/3 - y) (A"-- E). But by the equation (a:) since B" and A" are correspond- ing times, we have B"=A"-P-|-^(A''— E). Consequently substituting this for B" we get C'= A"-,P — Q + y ( A"-E) whence A"= P + Q + C"— y { A"— E) = P + Q + C"-y (P + Q + C"-E) neglecting the square and higher powers of y : 112 Mr, Herschel's account of a series of observations Consequently, still neglecting the same things we get C— Z"— y {P+Q+C— E} for the difference of the timekeepers C and Z reduced to the epoch, and putting R= mean of all the (C - Z") - y.mean of all the (P+Q+C— E) R will be their most probable difference reduced to the fixed epoch. P, Q, and R, being thus obtained, we must obviously have for the correct difference of longitudes, A = P + Q+R. Now, substituting for P, Q, R, their values, this gives A=mean of (A — B) + mean of ( B' — C) + mean of(C' — Z") -{-^.mean of {A — E) + {y^P).mean of {P + B'— E) — y.mean 0/ (P + Q + C" — E) that is, reducing, A =zmean of (A— B) + mean o/(B'— C) + mean o/(C"— Z") + (3. mean of A-\' {y — fi), mean ofB' — y, mean of C _P/3_Qy. This value of A is however susceptible of still further reduction by substituting for P and Q their values ; which if done, and the powers and products of (3 and y neglected, as has all along been done, we get A = mean of {A — B) + mean o/(B'— C) + mean of (C'^Z") + ^.mean of A + (y — jS ) mean of B'— y. mean of C" — /3 . mean of (A — B) — y. mean of (B' — C) that is, finally (since the numbers of the observations of A and of B are necessarily equal, and therefore the mean of the values of A — B is equal to the mean of A — the mean for determining the difference of meridians, &c. lis of B, and so for the rest) reducing and striking out all the terms which desti*oy each other. A = mean of A — mean ofB-{- mean ofB' — mean of C •{• + mean of C" — mean of Z" + (2 { mean of B—mean of BI-^- yimean ofC — mean of C\ or simply, denoting by A, B, A', B', &c. no longer the indi- vidual observed times (to which there will be no occasion again to refer) but the means of all those which have cor- responding observations. A = A — B+B'— C+ C — Z" + i3(B-B')+y(C~C"( This expression is, as it obviously ought to be, independent of the arbitrary epoch E, which may be assumed any number of hours or days before or after the observations. The first line of this value of A may be regarded as an approximate one ; the second as a correction depending on the rates of the watches ; and it is clear that the several portions of which this correction consists are the respective gains of the chronometers on Sid. T. during the mean amounts of the delay of the message between the several stations, taking the expression in its algebraical sense, where a negative delay corresponds to an anticipation. If all the signals succeeded, the coefficients of jS and y would be each o** 5", and the amount of the correction would be ( jQ + 7 ) •-|-T= ^^ • It would therefore require no less a deviation of one of the chronometers from its assumed rate than 29^" per diem, or of both of them i4j, and the same way, to produce an uncertainty in the result to the amount of a tenth of a second; deviations incompatible with the MDCCCXXVI. Q 114 Mr. Herschel's account of a series of observations character of ordinary good watches, not to speak of chro- nometers. The worst case that can happen is where the first signal only at a gives corresponding observations at the stations adjacent, the last only at 6, the first again only at c, and so on. In this case the coefficients of /3 and 7 would each equal the whole interval between the first and last signal at each post, or (in the present case) 1^ so"". The correction here would be ^2 X 24 — 16 In this extreme case, the sum of the deviations of both watches from their assumed rates, need only amount to i'.6 to produce an uncertainty of a tenth of a second in the result ; and though such a case as here supposed is in the last degree improbable, yet as a certain approach to it is not unlikely, it may be of use to show how the rates of the watches, if not otherwise known, may be obtained, or if known, verified, by the observations themselves. If we consider the observations on two successive nights, at two of the extreme stations, A and B for instance, calling A and B the means of the simultaneous observations on the first night, and A^ B^ on the second, we have, assuming for an epoch some time E = any number of days before either of the night's observations, b^r- P = A— .B + iG(A — E) But since this is generally true, if the observations be made in sufficient number on both nights to destroy their indivi- dual errors in the mean result, we must also have P = A,-B,+ /3(A,-E) equating which we get for determining the difference of meridians, &c. 115 A — B — /3(A — E)=A,— B, — ^(A, — E) whence we find , , „ , , ^ „, ^ (A, — B,) — (A — B) H — A, — A In this formula it is to be observed that A, and B^ are each greater than 24 hours ; but as timekeepers only register excesses above 12 hours and its multiples, if we wish' to denote by A^ and B^ the mere readings off of the time- keepers, we must put 24*^ + A^ and 24^ + B, for A^ and B^ if the interval be one day ; 48^ + A, and 48^ + B, if two days, and so on, so that (n being the number of days elapsed) ^^ ^^* — 5 = (A.-B,)-(A-B) f^ n X 24*+ A^ — A In like manner may the rate 2o'-6, which produces a correction of — o'-i7, or nearly two-tenths of a second in the result of that night's obser- vations. If we examine the individual observations of both nights, on which this rate depends, we shall find no satisfaction, though they tend to confirm the suspicion of a derangement 118 Mr. Herschel's account of a series of observations in the intervening day, by indicating rather a gain, than a loss on mean time ; — but the unavoidable errors of observa- tion vv^ill not permit the deduction of a rate from such short intervals as those elapsed during the observations of a single night. How^ever, we may be relieved from the disagreeable ne- cessity of rejecting the night's observations on this score, by reflecting, that all observations are liable to some errors ; that if we reject this on account of a suspected error of two tenths of a second, arising from the fault of a chronometer, we certainly should not be warrantable in retaining the re- sult of the observations of the 21st, where the whole night's work rests on a single signal, and on the transit of a single star observed at Greenwich, and where an error to the ex- tent of nearly half a second, from both causes united, may very fairly be presumed. We may be relieved, I say, from the necessity of rejecting observations where there are as- suredly none to spare, by remarking that, according to any fair estimation of the weight of each night's result from the number of observations, the most suspicious result, that of the 21st, is precisely that which holds the lowest rank — and that whether we retain or reject those of the two nights in question, the ultimate result will (as will hereafter appear), be unaffected to the extent of more than three-hundredths of a second. for determining the difference of meridians^ &c. Actual Calculation and Results. Computation of the observations of the i8th. 1st Combination. All the observers taken jointly. 119 ( — 6 i8'>i5'"4o'-37 18 45 44-13 io''29°'34'*4 10 49 32 '8 10 59 33 -6 Mean. Mean. 18 32 21 -88 10 46 13-6 A — B = B'— C'= C" — Z" = 7 46 8-28 o 8 22 '43 7 54 3071 -7 45 4-31 o 9 26*40 --4-82 — 0*17 O'CO 9"54'"52'"o 10 14 54 'O Mean. 10 4 53 -o B~ B'= C- C"= 9h46»29'75 10 6 31 '40 Mean. 9 56 30-57 + 41 20 '60 — II 57-56 + 29 23 -04 Gain of mean on 7 g Sid. Time - I -4-»2 C" 9'»4i' 9 5» 10 I 10 II 10 21 10 41 Z' '46s -2 49-6 50-3 48-6 46-9 47-2 Mean. 10 8 28*13 i7'»26'"46'-25 17 36 51 -02 17 46 53 -62 17 56 53-31 18 6 53 -42 18 26 57*05 Mean. »7 S3 32-44 Gain on M. T. of B— o -17 of C — o -00 I o 9 21 -41 1= Corrected difference of Longitudes. Computation of the observations of the 19th. 1st Combination. All the observers taken jointly. A r- i7«»29'"29'-6 18 Z9 52-5 18 49 43-4 B 9" 39'"3o'-4 10 49 41 -I 10 59 30-4 9° 44"49'-4 9 54 49 '9 10 34 49 -7 10 54 53 -4 Mean. 18 19 41 •83 A-B = B'— C'n C"— .Z" = Mean. 10 29 33-93 +7 50 7 '9'=^ + 8 16-II +7 58 24-01 —7 49 275 9 21 -26 + 0-33 — 0-02 0-00 Mean. 10 17 20 -60 B — B'= C'-C"= 9''36 33"io 9 46 36 •(>$ 10 26 33 -70 10 46 37-55 Mean. 10 9 4-49 + 12 13-33 — 14 13-02 I— I 59-69 Gain of mean on T Sid. T. - - I + °'33 C" Z" 9" 42'"o«-45 9 5» 53-65 10 I 56-50 10 22 2*45 10 32 24-75 10 41 59'8o 10 51 11 2 59-60 3-40 i7''3o'n56'-55 ij 40 5t -34 17 50 55 '77 18 II 5*09 18 21 18 31 18 41 18 51 28 -65 5.58 7-11 12 -50 Mean. 10 23 17-57 Mean. 18 12 20-32 Gain of B on M. T. — 0-02 of C O'oo 0921 •57J=: Corrected difference of Longitudes. 120 Mr. Herschel's account of a series of observations Calculation of the observations of the 2 1 st. 1st. Combination. All the observers jointly. A 17 47 32*10 18 7 40*95 18 17 30*30 »8 37 4075 18 57 43*90 -A. B 9^39°24s*7o 9 49 3270 10 9 38 .60 10 19 26-40 10 39 33 *20 10 59 33*30 B' 9''54"'5o'*4o 10 4 53-10 10 14 51 '20 10 34 49 -60 10 44 59 .40 11 4 51 *8o 9»'46>»38''*95 9 56 4'- 50 10 6 39* 80 lo 26 38* 25 10 36 47* 90 10 56 41- 10 C" 9h 42" in ■^ — ^ Z" 17'' 38m56s-io Mean. 18 14 15*18 A — B: B'— C: C'-Z"= Mean. 10 16 If -49 7 58 3*69 8 11*33 Mean. 10 26 32-58 B-B' = C'~C" = Mean. 10 18 21 '25 — o 10 21 -09 +0 36 13-55 Mean. 9 42 77 Mean. 17 38 56 -lo Gain of Bon M. T.n + 0*0 1 C . . . —0*03 8 6 15 *02 -7 56 48-40 +0 25 52-46 Gain of mean on Sid. Time. 9 26 *62 —4-54 +0 *OI —0*03 }- 4*54 o 9 22.06 Corrected difference of Longitudes. Calculation of the observations of the asd. 1st. Combination. All the observers jointly. A J . * '^ ' B' f- ^ nt \ C" , A '7« 1\ , 17" 3i™i28*i5 17 51 18 -70 9'»29™i8'*6 9 49 21 -9 9 59 17-1 10 9 21 -7 10 19 41 .7 10 29 28 .4 10 49 23 .0 9''44"5o"5o 9 54 53-50 9''36™39s-8o 9 46 42 -45 9 56 42-50 10 6 57*85 10 16 37-50 10 26 48 .05 10 36 47 -00 10 46 37.15 10 56 37.90 9'»32°' 8^*95 9 42 6 *95 9 52 8-55 1029 -90 i7''32'"53'*27 17 42 53.36 i8 1 15-65 18 11 21 -70 18 21 43 -60 18 31 31 -80 18 51 29-80 10 4 53 *20 lo 15 8 -60 10 24 48 *30 10 34 58*70 10 44 57 *6o 10 54 47.70 11 4 48 .80 17 52 56.56 18 2 59.28 Mean. 18 11 24-77 Mean. 10 9 24*63 8 2 0*14 8 io*74 Mean. 10 24 54-10 B-B'= C'--C"= Gain of Mean SiH Time Mean. 10 16 43-36 — 15 29-47 + 29 34*78 Mean. 9 47 8*58 Mean. 17 47 55 '62 A — B=: B'- C = Gain of B on M. T. +0-01 C . . . — 0-03 C— Z"= 8 10 10*88 -8 0 47 -04 + H 5 -31 °"l-2-3i 9 23 -84 -2*31 + 0 -oi -3 03 0 9 21 -51 r= Corrected d lifference of Lo ngitudes. for determining the difference of meridians ^ &c. Calculation of the observations of the i8th. 2d Combination. Capt. Sabine. Mr. Herschel. i»i A , '' i8*i5™4os'37 35 4»-i3 45 44 '^3 , B Io'*2 9ni34S'4 49 32 '8 59 33-6 Mean =: 18 32 21 -88 A — B = B'— C'= C*— Z" = Mean = 10 46 13 '6 7 46 0 8 8-28 22-45 7 54 -7 45 30-73 4 "34 9 26 -39 —4-82 — 0-17 •01 B' 9'' 54™ 52' 10 14 54 Mean = 10 4 53 C 9'i46'n29'-7 10 6 31 '4 Mean — 9 56 30-55 B - B' = -f C — C'=: — (B — B') + (C'-C")=: Gain of mean 7 g iSid.Timej-~4"a2 C 9''4i'n46s-o 51 49-5 10 1 50 '3 II 48.6 21 47 .0 41. 47 '2 Mean = 10 8 28 -1 Z" I ^h 26ni 469-25 18 36 46 56 6 26 51 -02 53-62 S3 '3^ 53 '42 57-05 Mean = . . 17 53 32*44 41 20 -60 Gain on M.T.-o- 1 7 *^ 57 -SSGainonM-T.-o-oi 29 23 -05 o 9 21 -39 z: The corrected difference of Longitudes Calculation of the observations of the 19th. 2nd Combination. Observations of Capt. Sabine and Mr. Herschel. A ' i7*29™293-6 18 39. 52*5 18 49 43*4 C ^ B B' , A. C C" , A '7." 9^39'"3o**4 10 49 41 -2 10 59 30 -o 9 54™5o**o 10 34 49-6 10 54 53 -6 9'»46m33s-8 10 26 33 -7 10 46 37 -6 9'' 42n» OS-5 9 51 53'^ 10 I 56-4 10 22 2 -5 10 32 24-8 10 41 S9'7 10 51 59*8 11 2 3-5 i 7** 30^568-55 17 40 51 -34 17 50 55-77 1 8 II 5-09 18 21 28-65 1831 5-58 18 41 7 -u 18 51 12 -50 Mean. 18 19 41-83 A-.B=: B' - C'= Mean. 10 29 33 -87 + 7 50 7 '9^ -f 0 8 16-04 Mean. 10 28 11 -07 B — B' = + C — C" = - Gain of mear Mean. 10 19 55-03 6 1 22 - 8 0 3 22- 6 Mean. 10 23 17-63 Gain of B on ^ C Mean. 18 12 20*32 /I.T. = 0.00 O'OO C— Z' = + 7 58 24-00 — 7 49 2 -eg 0 I 59- 8 l)= + o-33 9 21 -31 + 0-33 -f 0 -00 — 0 -oo 0 9 21 -64 Corrected diffe rence of Longi tudes. MDCCCXXVI. R 122 Mr. Herschel's account of a series of observations Calculation of the observations of the 21st. 2d Combination. Observations of Capt. Sabine and Mr. Herschel. A , — - 17 47 32-10 17 7 40*95 18 17 30*30 »8 37 4075 18 57 43 -90 Mean. 18 14 15 '18 A — B = B'— C' = C' — Z'z: i39™24''-8 49 32-8 38-4 10 19 26*4 »0 39 33 -2 10 59 33-2 Mean. 10 16 II '47 7 58 3 7» 8 II 36 8 6 1 5 -07 -7 56 48 -40 9 26 67 — 4'54 O'OI + 0-03 o 9 22 '15 B' 9" 54'"5o''-4 10 4 53-2 10 14 51 '2 10 34 49-6 10 44 59-4 u 4 52 'o Mean. 10 26 32 '63 B — B' = C — C"= 9^ 46'°398'o 9 56 41 '5 10 6 39 -8 lo 26 38 '3 10 36 47 '9 10 56 41 •! Mean. ID 18 21 '27 — o 10 21 '16 +0 36 13 'S7 + 0 25 Gain of mean on 7 Sid. T. - j - 52-41 4*54 C" r— 9'' 42° 7^7 Mean. 9 42 77 i7>»38'"56*-io Mean. 17 38 56-10 Gain of B on meanT. — o -o i ofC - - +o- 3 Corrected difference of Longitudes. Calculation of the observations of the 22d. 2d Combination. Observations of Capt. Sabine and Mr. Herschel. 17*31n>I2*-I5 17 51 18 -70 18 I 15 -65 18 II 21 -70 18 21 43 -60 18 31 31 -So Mean. »8 4 43 -93 A — B = B'— C = C-Z" = ^ B 9'»29'°i8s 6 9 49 22 -o 9 59 «7 -2 10 9 32 -O 10 19 41 -6 10 29 28-6 Mean. 10 2 45 -00 8 0 I 58 -93 8 10 -86 8 8 10 9 -79 0 46 -95 9 22 '84 I -22 — o -03 + o -03 O 9 21 '62 B' 9»'44"5o^-8 9 54 53 -6 10 4 53 -2 10 15 8 -8 10 24 48 '4 10 34 58 '8 10 44 57 -6 10 54 48 -o 11 4 48 -8 Mean. 10 24 54 -22 B — B' =z C— C" = C 9h 36"39'-8 9 46 42 -5 9 56 42 -5 10 6 58 -o 10 16 37-3 10 26 48 -2 10 36 47 -o 10 46 36-9 10 56 38 -o Mean. 10 16 43 •36 — 22 9-2 + 29 34 7 + 7 25 -5 Gain on Sid. T. — i -22 9" 32'" 9»-o 9 42 7 -o 9 52 8*6 10 2 10 'I Mean. 9 47 8-67 •7''32'"53"*27 17 42 53 .36 17 52 56 -56 18 2 59 -28 Mean. 17 47 55 -62 Gain of B on M. T. — 0*03 of C - - + o-oj = Corrected difference of Longitudes. Jor determining the difference of meridians ^ ^c. 123 Calculation of the observations of the 18th. sd Combination. Capt. Sabine (for Col. Bonne) — M. Largeteau. i\ f— 18* i5'°40''37 35 41 -13 45 44 •»3 Mean. 18 32 21 -88 A — B = B' — C'= c— z*= A = I o** 2 9"' 3 4s '4 49 32 -8 59 33 -6 B' I — -A.- c 9"54™52*'o Mean. 10 46 13 '6 7 46 8 -28 O 8 22 '20 7 54 30 -48 -7 45 4 -41 o 9 26 -07 — 4-68 — o -ai O '02 o 9 21 •16 Mean. 9 54 52 'o B — B' = e— C-= 9'» 46'n29**8 Mean. 9 46 29 '8 051 21 '6 -o 22 47 7 Gain of mean on Sid. T. o 28 33 -9 }=-4 68 C" ,, 9*'4i«n46s-4 5» 49 V 10 21 46 '8 41 47-2 Mean. 10 9 17 '52 > Z" i7»«26">46»*25 36 51 -02 18 6 53 -42 26 57 -05 Mean. 17 54 21 -93 Gainof BonM.T.r:— o '21 of C - - — O '02 The corrected difference of Longitudes. Calculation of the observations of the 19th. 3d Combination. Col. Bonne and M. Largeteau. A , i8*'39"52s-5 18 4^ 43 -4 Mean. 18 44 47 -95 A — B = B' — C'= C — Z"=- N io'»49™4is o 10 59 30 -8 Mean. 10 54 35 -90 7 50 12 -05 8 16 -08 7 58 28-13 7 49 2 *8o 9 25-33 — 378 + 0-04 — o-oi B' 9'*44"49^-4 9 54 49*8 10 34 49-8 10 54 53-2 Mean. 10 17 20 '55 > C 9*" 36'"33'*2 9 46 33 -5 10 26 33 '7 10 46 37 -5 Mean. 10 9 4-47 B — B'= + o 37 15-35 C— C" = — o 14 13-05 + o 23 2-3 Gain of mean 7 g on Sid. Time 3 ^ ' C" 9'' 42" 9 51 10 I 10 22 10 32 10 41 10 51 11 2 ' 03-4 53-5 56-6 2*4 247 59-9 59*4 3-3 Mean. 10 23 17 -52 i7i'3o«'56g-55 17 40 51 -34 '7 50 55 77 1 8 1 1 5 '09 18 21 18 31 18 41 18 51 28-65 5-58 7-11 12 -50 Mean. 18 12 20-32 Gain of B on M.T. = + o 04 C - - — o-oi o 9 21 -58 ICorrected difference of Long itudes. 124 Mr. Herschel's account of a series of observations Calculation of the observations of the 21st. 3d Combination. Observations of Col. Bonne and M. Largeteau. A i7*'37°'23S'io 17 47 32 'lO 18 7 40-95 18 57 43 '90 Mean. 18 7 35 -oi A — B=: B'~C'= C— Z" = B 9'» 39"'24S'6 9 49 32 -6 10 9 38 -8 10 59 33 -4 Mean. 10 9 32 '35 7 58 2 '66 8 1 1 -45 8 6 14 '11 -7 56 48 -40 9 25 '71 -3 iS — o '04 +0 -04 o 9 22 '57 B' , io''34™49S'6 10 44 59 -4 Mean. 10 39 54-50 B- B' = C- C" = I0''26"'38s-2 10 36 47 '9 Mean. 10 31 43 -05 — 30 22 '2 + 49 35 -3 + 19 13 I Gain of mean on i Sid. T. - - > 3 -15 C" 9'>42>7 TJ' i7''38"s6'"io Mean. 9 42 7 7 Mean. 17 38 56-10 Gain of B on meanT.— o -04 of C - - + o -04 'OSDfiSTo'-fl'h ' Corrected diflference of Longitudes. Calculation of the observations of the ssd. sd. Combination. Col. Bonne and M. Largeteau. A _ .-A- n E' ^ '^' C" r—^ 9i»32'°8"-9 9 42 6-9 9 52 8-5 10 29-7 '' >, Z" i7'»5i°'i8*-7o 18 I 15*65 18 II 21-70 18 21 43-60 18 31 31-80 18 51 29-80 9''49"2i-8 9 59 »7 -o 10 9 21 '4 10 19 41 -8 10 29 28 '2 10 49 23 -0 9»'44"5os-2 9 54 S3 -4 10 15 8 -4 10 24 48 '2 10 34 58 -6 10 54 47 -4 11 4 48 -8 9*'36™39''8 9 46 42 .4 10 657. 10 16 "^7 7 10 26 47 -9 10 46 37 -4 10 56 37-8 i7*'32"'53«-27 •7 42 S3 -36 17 52 56 -56 18 2 59 -28 Mean. 18 18 6-88 A — B = B — C'= Mean. 10 16 5 '53 8 2 i-3S 8 10 -61 Mean. 10 24 53 -57 B — B' = C— C" = Gain of mean Sid T Mean. 10 16 42 -96 — « 48-1 + 29 34 -5 Mean. 9 47 8 -50 Gain of B on ^i ofC Mean. 17 47 55-62 T. =-0-01 - +0-02 C— Z"= 8 10 11 -96 -8 0 47 -12 4- 20 46-4 S=-3-4o 9 24 -84 — • 3 '4° — 0 -01 + 0 -02 0 9 21 -45 = Corrected d lifFerence of Lo ngitudes. . . j' for determining the difference of meridians , &c. 125 In appreciating the weights to be attrihuted tp; these several results, it is obvious that the numbers of corresponding observations at each pair of stations, and of transits at the observatories, as it essentially influences the probable accu- racy of the mean comparison of their timekeepers must be the elements of all fair estimations. If corresponding ob- servations at any station be wanting, the weight is evidently r\othing; so that calling x,y, z, the numbers of correspond- ing observations at A and B, at B and G, and at C and Z M respectively, x xyxz must necessarily be a multiplier of the function expressing the joint weight of the whole. But if the number of observations at any one station, or at all, be j.,,^,, infinitely multiplied, the weight is clearly not infinite. If at all the stations, it would afford only such a degree of evi- dence as a perfect comparison of the clocks would give, which is but a relative certainty, after all, and may be denoted by unity. In like manner, if the observations at any one pair of stations be infinitely multiplied, the result is still open to all the errors of imperfect observations at the rest, so that unity will in like manner be the maximum of the coefficient depending on any separate set. The function ja y z is the simplest which satisfies these conditions, each factor vanishing when its variable is 0, and becoming unity when infinite. The same reasoning applies to the transit observa- tions by which the clocks are compared with the stars, so that calling T and t the number of transit observations taken at each, by which the clock's errors are obtained, the function expressive of the weight of any night's observations will be 126 Mr, Herschel's account of a series of observations , &c. T X V z t W = T + I ^ jr + 1 ^y + 1 ^ Z+ 1 ^^ + I * It would be needless refinement to enquire minutely how far this agrees with a strict calculation of probabilities. The result of the whole operation may then be briefly stated as follows : Day of Obs. A X y % T t W Wx(A— 9"'2l'') I8th. 9™ 2l'-4l 3 2 6 5 6 i-T.f-i-f-O-31 0-1271 19th. 9 21 '57 3 4 8 S 3 l.£.|.l.|.=0-30 01710 21 St. 9 22 06 6 6 1 4 1 l-.f-T^-i— 0-15 01590 22d. 9 21 -51 7 9 4 5 5 i-TV*-i-f-0-44 0*2244 Sum i-2o)o'68i5(o-568=:mean. 9 2» '535 9 2 1 '64 9 21 70 Most probable mean of the whole, so obtained - - - = g^2i*'^6S Mean, similarly taken, but rejecting the results of the 18th and 21st as liable to suspicion ------- Arithmetical mean of all the four results - - . Arithmetical mean of the results of the four nights, obtained by the 2d combination, or from Capt. Sabine's and Mr. Herschel' observations alone ------- Arithmetical mean of the 3d combination, or Col. Bonne's and "I „ ,1 '60 M. Largeteau's observations taken separately - - . J On the whole then, 9*" 21 "'6 may be assumed as a result not very likely to be altered a whole tenth of a second, and very unlikely to be altered to twice that extent, by future determinations. J. F. W. HERSCHEL, Xx>ndon, November 2, 1825, C 127 3 IX. Observations on the poison of the common toad. By John Davy, M. D. F. R. S, Read December 22, 1825. Xn every country in which this animal is found, it is con- sidered poisonous by the common people ; and the opinion may be traced back to a very remote antiquity. Of late years the notion has been rejected by the professed naturalist, and placed in the number of vulgar prejudices. Thus, M. CuviER speaking of the common toad, remarks: " Ce sont des animaux d'une forme hideuse, d6goutante, que Ton accuse mal-a-propos d'etre venimeux par leur salive, leur morsure leur urine, et meme par Thumeur qu'il transpirent." In this, as in some other instances, the common and long received opinion is w^ell founded, and that of the philosopher hastily and erroneously formed. The poison of the common toad, I find, is seated chiefly in the integuments, in follicles in the cutis vera, beneath the cuticle and the coloured rete mucosum. These follicles are largest and most numerous near the shoulders, and about the neck of the animal ; yet they are very generally distri- buted, and even on the extremities. Pressure being applied to the skin, a yellowish thick fluid exudes, and occasionally spurts to a considerable distance. It may be collected with ease in sufficient quantity for examination. It possesses, I • Le regne animal distribue d'apres son organisation ; torn, il p. 94. Paris, 181 7. 128 Dr. Davy's observations on the have ascertained, the following properties. The greater part of it is soluble in alcohol and water. The aqueous solution is slightly viscid, and does not pass readily through a common philter. It is not precipitated by acetate of lead ; and its transparency is very slightly impaired by corrosive sublimate. The substance obtained by evaporation, both from the aqueous and alcoholic solution, is light yellow, and transparent ; has a faint and peculiar smell different from that of the toad, and it is slightly bitter, and very acrid, acting on the tongue like the extract of aconite prepared in vacuo, and even occasioning a smarting sensation when applied to the skin of the hand, and its effect lasts two or three hours. When heated, it readily melts, burns with a bright flame, and does not emit an ammoniacal odour. It is neither acid or alkaline, judging from its not changing the colour of litmus or turmeric paper. Caustic ammonia dis- solves it ; the solution remains acrid. Nitric acid also dissolves it ; the solution is of a purple colour ; neutralized by an alkali it is less acrid, as if partially decomposed. The small portion of the fluid, not soluble either in water or alcohol, and to which it owes its consistence, is probably a variety of albumen ; and its appearance when burning would seem to warrant this idea. Though this fluid of the toad is more acrid than the poisoi> of the most venemous snakes, I do not find that it has any in-v jurious, and much less fatal effect, when absorbed and carried into the circulation. A chicken punctured with a lancet dipped in it, received no inj ury : and in confirmation of this statement I may remark, that though, as already observed, it abounds chiefly in the integuments, it is not confined to poison of the common toad. 129 them ; 1 have detected it in a notable quantity in the bile, in a minute quantity in the viscid fluid lubricating the tongue, and also in the urine, and even in the blood. Reflecting on the use w^hich this fluid may.be of to the toad, it has occurred to me that it may answer two purposes, and these of importance to this abhorred but innocent reptile. As the external surface of the skin is smeared with this " sweltered venom '' (the very appropriate epithet given it by our great dramatic poet), it must serve to defend it against the attacks of carnivorous animals : " a toad to eat " is a proverbial expression well known ; and the facts adduced show its propriety and force. I may here add, that nature has given this animal an additional security against attack, in providing it with integuments of great thickness, and strength, and hardness ; which last-mentioned quality is imparted by a layer of cutis almost analogous to bone, immediately under the rete mucosum, abounding in phosphate and carbonate of lime, and carbonate of magnesia, semi-transparent, and yet so firm that it is not easily cut. As the fluid contains a substance which is very inflamma- ble, and as it may be considered excrementitious, though the blood is very slightly impregnated with it, it may serve to separate a portion of carbon from the blood ; and thus in its formation be auxiliary to the function of the lungs. In sup- port of this idea, I may remark, that I find the pulmonary arteries of the toad are each divided into two branches, one of which goes to its respective lung, and the other, very little smaller, to the cutis, between the head and shoulder, on each side, and is extensively ramified where the largest MDCCCXXVI. S 130 Dr. Davy's observations on the venom-follicles are situated, and where there is a plexus of veins of great size, as if intended for a reservoir of blood. This last-mentioned peculiarity of structure, and the situa- tion of it, corresponding to the site of the gills of the tadpole, would seem to indicate, that the sub-cutaneous distribution of the second branch of the pulmonary artery, may aid the lungs farther in their office by bringing the blood to the surface to be acted on by atmospheric air. I have endeavoured to ascertain if there is any direct com- munication by spiracula through the integuments. The results I have obtained have been negative. I have intro- duced air through a small incision, by means of a forcing syringe, under the loose skin, also into the cavity of the abdomen, and into the lungs by the superior glottis. The air has been very much compressed under water, yet it has been completely confined, not the smallest bubble having been forced through the skin, or the lungs. When dried, the skin of the toad exhibits two kinds of pores ; one kind, few in number, confined to the two tube- rosities over the shoulders, sufficiently large to admit a hog's bristle ; the other kind, very numerous, scattered over the whole surface, and very minute. They are both of them best seen by holding the skin between the eye and a strong light; the smallest appears as luminous points of a yellow hue ; the largest as indistinct circles. Both are covered externally with transparent cuticle, and internally by a deli- cate surface of cellular tissue ; some of the largest are also covered with rete mucosum ; the smallest appears to be destitute of this membrane. poison of the common toad. 131 Whether these apparent pores are the medium of com- municating between the blood in the sub-cutaneous capillary vessels, and the atmosphere ; or, whether they are merely the cutaneous apparatus of secretion and exudation, it is difficult to determine ; it is not improbable th^t they perform both functions. Corfu, September 15 th, 18*5. C 132 3 X. On the magnetizing power of the more refrangible solar rays. By Mrs, M. Somerville. Communicated by W, Somerville, M. D. F. R, S, Feb, 2. 1836. Read February 2, 1826. Xn the year 1813, Professor Morichini of Rome discovered that steel, exposed to the violet rays of the solar spectrum, becomes magnetic. His experiments were repeated by Pro- fessor CoNFiGLiACHi at Pavia, and also by Mons. Berard, at Montpellier, without success. I am not aware of any one having attempted them in this country, perhaps from the belief that experiments which had sometimes failed in Italy, were not likely to succeed in our more northern climate. The unusual clearness of the weather last summer, however, induced me to try what could be accomplished in this country. Accordingly, in the month of July, an equi- angular prism of flint glass, the three sides of which were each 1,4 by 1,1 inches, was fixed in a slit made to receive it in a window-shutter : by this prism a coloured spectrum was thrown on an opposite panel, at the distance of about five feet. I used for the subject of experiment, a very slender sewing needle an inch long, having previously ascertained that it was quite free from magnetism, by repeated exposure of both ends of it to the north and south pole of a very sen- sible magnetic needle, when it was found equally to attract either pole in every instance. The magnetic needle employed as a test in this experiment, is made of a sewing needle mag- Mrs, M. SoMERViLLE on the magnetizing power, &c, 133 netised, and run through a small piece of cork, into which a conical cap of glass is inserted ; the whole traverses on the point of a needle fixed perpendicularly in a stand. I had no information at this time of the manner in which Professor Morichini had conducted his experiments ; but it occurred to me that it was not likely that if the whole of the needle were equally exposed to the violet rays, the same influence should, at the same time, produce a south pole at one end of it, and a north pole at the other. I therefore covered half of the needle with paper, and fixed it to the panel with wax, between ten and eleven in the morning, in such a position that the uncovered part of it should be exposed to the violet rays. The needle was placed in a vertical plane, nearly perpendicular to the magnetic meridian, and inclined to the horizon. As I had not a heliostat, it was neces- sary to move the needle in a direction parallel to itself, to keep the exposed portion of it constantly in the violet ray. The sun was bright at the time, and in less than two hours I had the gratification to find that the end of the needle which had been exposed to the violet rays attracted the south pole of the magnetic needle, and repelled the north pole. It had been previously ascertained that there was no iron near to disturb the results. The experiment was also repeated on the same day, under precisely similar circum- stances, with the view of detecting any source of error that might have escaped observation in a first attempt ; but the result was the same as in the first. The season was so favourable that it afforded me daily opportunity of repeating the experiments, varying the size of the needles, always taking especial care to ascertain that 134 Mrs. M. SoMERViLLE on the magnetizing power they were free from magnetism. The needles were placed in various directions in the plane of the magnetic meridian^ sometimes in the angle of the dip, sometimes perpendicular to the magnetic meridian, and also at various angles with regard to it. In some cases the heads of the needles were exposed in place of the points, to the violet rays. Perhaps it might have been expected that the influence would have been greater in those instances in which the needles were placed in the plane of the magnetic meridian, and at the angle of the dip ; and, consequently, polarity might have been expected to take place in a shorter time under these circumstances ; yet in fact there seemed to be no difference ; most of the needles became magnetic, some in longer, others in shorter periods, varying from about half an hour to four hours, but depending on circumstances which I have not yet been able to detect, further than that a number of results induced me to believe, that the experiments were more suc- cessful from ten to twelve, or one o'clock, than later in the day. The portion of the needle exposed was almost always a north pole, whether it pointed upwards or downwards. In a few instances in which the contrary occurred, it may possi- bly have arisen from some previous disposition in the needle to magnetism, too shght to be observed. The distance of the needle from the prism was frequently varied by fixing the needle to the wooden pole of a fire- screen, but without material variation in the effect. I found it unnecessary to darken the room ; it was sufficient to place the prism so as throw the spectrum on any place out of the sun's rays. My next object was to endeavour to ascertain whether any of the more refrangible solar rays, 135 other of the more refrangible rays had the same property as the violet. A set of needles carefully examined as before, were therefore subjected to the different rays of the solar spec- trum ; the needles exposed to blue and green rays, sometimes acquired the magnetic property, though less frequently, and requiring longer exposure than when the violet rays were used; but the magnetism seemed to be equally strong in these as in the examples of the violet rays. The part exposed became a north pole. The indigo rays succeeded almost as well as the violet. Pieces of clock and watch spring were next tried, under the idea that they might, possibly from their blue colour, be more susceptible of magnetic influence, and it was the case; their greater extent of surface however, or their softness, may have contributed to this susceptibility. The pieces of spring were from tv*^o to three inches long, and from the eighth to the half of an inch broad. It was difficult to procure watch and clock spring free from magnetism ; it even hap- pened on one occasion, that although the roll of spring was neutral, the pieces into which it was cut became magnetic ; in one instance the pieces were heated so as to deprive them of magnetism and colour; they then required longer expo- sure to the rays in order to acquire polarity. Large bodkins were exposed to the violet rays without effect, the mass per- haps being too great. When needles already magnetic were tried, their magnetism was increased. Dr. Wollaston was so kind as to lend me a very large lens, having its centre covered with paper, which he had used in his investigations respecting the chemical rays. The lens concentrated the violet rays, and produced a magnetic effect in a shorter time 1S6 Mrs. M. SoMERViLLE on the magnetizing power than the prism ; but the rapid motion of the sun made it difficult to keep the needle in the focus. The effect was pro- duced with equal facility by throwing the spectrum on the floor of the room ; but success could not always be depended upon even when the weather seemed most favourable. I now made the following experiments with blue glass. Three needles free from magnetism, having one half covered with paper, were laid horizontally on the stone outside of a south window, under a dark blue glass coloured by cobalt, in a very hot sun ; after remaining in this position between three and four hours, they were found to have become feebly magnetic, the uncovered part being a north pole. On exa- mining these needles the following day, they had lost their magnetism, a circumstance which had not before occurred, though it was observed sometimes to take place afterwards, as the force of the sun diminished from the advance of the season. There was no iron near, and the magnetic needle when placed on various parts of the stone, showed no mag- netic influence in it. Next day the experiment was repeated with this difference, that the needles were left exposed to the sun, under the blue glass, six hours ; and then the needles had not only acquired very sensible magnetism, but still retain it, at the distance of nearly six months. Pieces of clock spring, which had been heated as formerly mentioned, also became magnetic under the blue glass. I was desirous of ascertaining whether this kind of glass suffered the chemical rays to pass, and thereby occasion these changes in the steel, therefore I employed a liquid hold- ing muriate of silver in suspension, as a test, in the following manner: a piece of writing paper dipped in the liquid was of the more refrangible solar rays. 137 cut into two equal parts, of which one was placed under the blue glass, and the other under a white glass, as nearly at the same time as possible ; but the one did not become black sooner than the other ; nor on comparing them could any difference be perceived in intensity of colour, both having been equally exposed to the chemical rays. The experiment was repeated with the same result. On the 26th of August, the thermometer at noon being es"", two neutral pieces of clock spring were exposed to the sun, one under a thicker piece of the same blue glass, as in the former experiment, and the other under green glass ; both acquired polarity. 31st of August, the thermometer at noon 68®. Having thus succeeded in producing magnetism under the circum- stances described, I next tried the effect of exposing neutral pieces of clock spring to the sun, enveloped in violet and green silk. The half of each was covered with paper as before, and the pieces of spring then wrapped, one in green,- and the other in violet-coloured ribbon, were fixed to the inside of a pane of glass in a window, where they were left exposed to the sun all day ; in the evening both had become magnetic, although they were two of the pieces of spring already said to have acquired polarity more slowly from having been heated ; and as before, the parts exposed to the sun under the ribbon were north poles. To learn if heat had any share in producing magnetism jn this case, I exposed three pieces of the same steel to a bright sunshine, on the 1st of September, the thermometer at noon being at 70° : one half of each was covered with paper, but MDCCCXXVI. T Xy 158 Mrs. M. Somerville on the magnetizing power the Mher half had neither glass nor ribbon over it ; and althoiagh the heat was greater than on the preceding day, no itiagnetism was produced. On the 2d of September, thermometer at noon 68**, a ^iece of neutral white steel acquired polarity from exposure to the sun, enveloped in green ribbon, one half being covered with paper as before. Oh the 3d of Septertiber, thermometer at noon 68°, two pieces of neutral spring became magnetic, one exposed in a violet-coloured ribbon, and the other in blue glass, while a similar piece of spring was in no way affected by exposure to white light : the half of each was covered with paper. ?' September the 4th, thermometer at noon 68**, five large seiwirtg needles, two inches long, were exposed to the sun's rays, one in blue glass, one in green glass, one in violet ribbon, one in green ribbon, and one in white light ; the half of each was covered with paper. Of all these two only became magnetic, namely, those in the blue glass, and in the violet ribbon. ' 'On the 2oth of September, thermometer at 69^*^ I placed pieces of steel enveloped in violet and green ribbon, and Under glass of various colours, in different positions with regard to the magnetic meridian and dip. Several acquired polarity, the uncovered part being the north pole. A piece of steel became more strongly magnetic than usual, exposed in green ribbon, the position of which had been perpendicular tb t!he horizon, and nearly in the magnetic meridian. For Sdme time I still obtained similar results, though the mag- netism became more feeble as the season advanced, from the of the more refrangible solar rays. isd diminished force of the sun, in consequence of which further experiments were deferred till the return of summer shall afford me an opportunity of continuing them. From the results which have been stated, I am induced to believe that the more refrangible rays of the solar spectrum have a magnetic influence even in this country. "^^ [[ 140 3 XL On the mutual action of sulphuric acid and naphthaline, and on a new acid produced. By M. Faraday, F. R. S. Cor- responding Member of the Royal Academy of Sciences y ^c. &c. Communicated January 12, 1826. Read February 16, 1826. In a Paper on new compounds of carbon and hydrogen, lately honoured by the Royal Society with a place in the Philoso- phical Transactions, I had occasion briefly to notice, the peculiar action exerted on certain of those compounds by sulphuric acid. During my attempts to ascertain more minutely the general nature of this action, I was led to sus- pect the occasional combination of the hydro-carbonaceous matter with the acid, and even its entrance into the constitu- tion of the salts, which the acid afterwards formed with bases. Although this opinion proved incorrect, relative to the pecu- liar hydro-carbons forming the subject of that Paper, yet it led to experiments upon analogous bodies, and amongst others, upon naphthaline, which terminated in the production of the new acid body and salts now to be described. Some of the results obtained by the use of the oil gas products are very peculiar. If, when completed, I find them sufficiently interesting, I shall think it my duty to place them before the Royal Society, as explicatory of that action of sulphuric acid which was briefly noticed in my last Paper. Most authors who have had occasion to describe naph- thaline, have noticed its habitudes with sulphuric acid. Afr. Faraday on the mutual action of sulphuric acidy ^c. 141 Mr. Brands, several years since,* stated that naphthaline dissolved in heated sulphuric acid " in considerable abund- ance, forming a deep violet coloured solution, which bears diluting with water without decomposition. The alkalies produce in this solution a white flaky precipitate, and if diluted the mixture becomes curiously opalescent, in conse- quence of the separation of numerous small flakes." The precipitate by alkali was probably one of the salts to be hereafter described. Dr. KiDD observes, -f that " it blackens sulphuric acid when boiled with it ; the addition of water to the mixture having no -other effect than to dilute the colour, neither does any precipitation take place upon saturating the acid with am- monia.'' Mr. Chamberlain states, J that sulphuric acid probably decomposes naphthaline, for that it holds but a very small quantity in solution. The true interpretation of these facts and statements will be readily deduced from the following experimental details. 1. Production and properties of the new acid formed from sulphuric acid and naphthaline. Naphthaline, which had been almost entirely freed from naphtha by repeated sublimation and pressure, was pulve- rised ; about one part with three or four parts by weight of cold sulphuric acid were put into a bottle, well shaken, and left for 36 hours. The mixture then contained a tenacious * Quarterly Journal of Science , viii. 289, 18 19. f Philosophical Transactions, 1 821, p. 216. J Annals of Philosophy, N. S. vi. p. 136, 1823. 142 Mr. Faraday on the mutual action of sulphuric acid deep red fluid, and a crystalline solid ; it had no odour of sulphurous acid. Water being added, all the liquid and part of the solid was dissolved ; a few fragments of naphthaline were left, but the greater part was retained in solution. The diluted fluid being filtered was of a light brown tint, trans- parent, and of an acid and bitter taste. ^^ For the purpose of combining as much naphthaline as possible with the sulphuric acid, 700 grains, with 520 grains of oil of vitriol were warmed in a Florence flask until entirely fluid, and were well shaken for about 30 minutes. The mixture was red ; and the flask being covered up and left to cool, was found after some hours to contain, at the bottom, a little brownish fluid, strongly acid, the rest of the contents having solidified into a highly crystalline mass. The cake was removed, and its lower surface having been cleaned, it was put into another Florence flask with 300 grains more of naphthaline, the whole melted and well shaken toge- ther, by which a uniform mixture was obtained ; but opaque and dingy in colour. It was now poured into glass tubes, in which it could be retained and examined without contact of air. In these the substance was observed to divide into two portions, which could easily be distinguished from each other, whilst both were retained in the fluid state. The heavier portion was in the largest quantity ; it was of a deep red colour, opaque in tubes half an inch in diameter, but in small tubes could be seen through by a candle, or sun light, and appeared perfectly clear. The upper portion was also of a deep red colour, but clear, and far more transparent than the lower : the line of separation very defined. On cooling the tubes, the lighter substance first sofidified, and after some and naphthaline, and on a new acid produced. 14S time the heavier substance also became solid. In this state, whilst in the tube, they could with great difficulty be distin- guished from each other. These two substances were separated, and being put into tubes, were further purified by being left in a state of repose at temperatures above their fusing points, so as to allow of separation ; and when cold, the lower part of the lighter substance, and the upper, as well as the lower part of the heavier substance, were set aside for further purification. The heavier substance was a red crystalline solid, soft to the nail like a mixture of wax and oil. Its specific gravity was from 1.3 to 1.4, varying in different specimens ; its taste sour, bitter, and somewhat metallic. When heated in a tube, it fused, forming as before a clear but deep red fluid. Further heat decomposed it, naphthaline, sulphurous acid, charcoal, &c. being produced. When heated in the air it burnt with much flame. Exposed to air it attracted moisture rapidly, became brown and damp upon the surface, and developed a coat of naphthaline. It dissolved entirely in alcohol, forming a brown solution. When rubbed in water a portion of naph- thaline separated, amounting to 27 per cent, and a brown acid solution was obtained. This was found by experiments to contain a peculiar acid mixed with a little free sulphuric acid, and it may conveniently be called the impure acid. The lighter substance was much harder than the former, and more distinctly crystalline. It was of a dull red colour, easily broken down in a mortar, the powder being nearly white, and adhesive like naphthaline. It was highly sapid, being acid, bitter, and astringent. When heated in a tube it melted, forming a clear red fluid, from which by a continued 144 Mr. Faraday on the mutual action of heat much colourless naphthaline sublimed, and a black acid substance was left, which at a high temperature gave sul- phurous acid and charcoal. "When heated in the air it took fire and burnt like naphthaline. Being rubbed in a mortar with water, a very large portion of it proved to be insoluble ;^ this was naphthaline ; and on filtration the solution contained the peculiar acid found to exist in the heavier substance , con- taminated with very little sulphuric acid. More minute examination proved that this lighter substance in its fluid state was a solution of a small quantity of the dry peculiar acid in naphthaline ; and that the heavier substance was an union of the peculiar acid in large quantity with water, free sulphuric acid, and naphthaline. It was easy by diminishing the proportion of naphthaline to make the whole of it soluble, so that when water was added to the first result of the experiment, nothing separated; and the solution was found to contain sulphuric acid with the pecuhar acid. But reversing the proportions, no excess of naphthaline was competent, at least in several hours, to cause the entire disappearance of the sulphuric acid. When the experiment was carefully made with pure naphthaline, and either at common, or slightly elevated temperatures, no sulphurous acid appeared to be formed, and the action seemed to consist in a simple union of the concentrated acid and the hydro-carbon. Hence it appears, that when concentrated sulphuric acid and naphthaline are brought into contact at common, or mo- derately elevated temperatures, a peculiar compound of sul- phuric acid with the elements of the naphthaline is produced, which possesses acid properties ; and as this exists in large and naphthaline y and on a new acid produced, 145 quantity in the heavier of the bodies above described, that product may conveniently be called the impure solid acid. The experiments made v^^ith it, and the mode of obtaining the pure acid from it, are now to be described. Upon applying heat and agitation to a mixture of one volume of v^ater, and five volumes of impure solid acid, the v^^ater was taken up to the exclusion of nearly the whole of the free naphthaline present ; the latter separating in a co- lourless state from the red hydrated acid beneath it. As the temperature of the acid diminished, crystallization in tufts commenced here and there, and ultimately the whole became a brownish yellow sohd. A sufficient addition of water dis- solved nearly the whole of this hydrated acid, a few flakes only of naphthaline separating. A portion of the impure acid in solution was evaporated at a moderate temperature ; when concentrated, it gradually assumed a light brown tint. In this state it became solid on cooling, of the hardness of cheese, and was very deliquescent. By further heat it melted, then fumed, charred, &c. and gave evidence of the abundant presence of carbonaceous matter. Some of the impure acid in solution was neutralized by potash, during which no naphthaline or other substance separated. The solution being concentrated until ready to yield a film on its surface, was set aside whilst hot to crys- tallize : after some hours the solution was filled with minute silky crystals, in tufts, which gave the whole, when stirred, not the appearance of mixed solid salt and liquid, but that of a very strong solution of soap. The agitation also caused the sudden solidification of so much more salt, that the whole MDCCCXXVI. U 146 Mr. Faraday on the mutual action of sulphuric acid became solid, and felt like a piece of soft soap. The salt when dried had no resemblance to sulphate of potash. When heated in the air, it burnt with a dense flame, leaving com- mon sulphate of potash, mixed with some sulphuret of potassum, resulting from the action of the carbon, &c. upon the salt. Some of the dry salt was digested in alcohol to separate common sulphate of potash. The solution being filtered and evaporated, gave a white salt soluble in water and alco- hol, crystaUine, neutral, burning in the air with much flame, and leaving sulphate of potash. It was not precipitated by nitrate of lead, muriate of baryta, or nitrate of silver. It was now evident that an acid had been formed peculiar in its nature and composition, and producing with bases peculiar salts. In consequence of the solubility of its barytic salt, the following process for the preparation of the pure acid was adopted. A specimen of native carbonate of baryta was selected, and its purity ascertained. It was then pulverized, and rubbed in successive portions with a quantity of the impure acid in solution, until the latter was perfectly neutralized, during which the slight colour of the acid was entirely removed. The solution was found to contain the peculiar barytic salt. Water added to the solid matter dissolved out more of the salt ; and ultimately only carbonate and sulphate of baryta, mixed with a little of another barytic salt, remained. The latter salt being much less soluble in water than the former, was not removed so readily by lixiviation, and was generally found to be almost entirely taken up by the last portions of water applied with heat. \)\ih ^^d naphthaline, and on a new acid produced. 147 The barytic salt in solution was now very carefully de- composed, by successive additions of sulphuric acid, until all the baryta was separated, no excess of sulphuric acid being permitted. Being filtered, a pure aqueous solution of the peculiar acid was obtained. It powerfully reddened litmus paper, and had a bitter acid taste. Being evaporated to a certain degree, a portion of it was subjected to the continued action of heat ; when very concentrated it began to assume a brown colour, and on cooling became thick, and ultimately solid, and was very deliquescent. By renewed heat it melted, then began to fume, charred, but did not flame ; and ulti- mately gave sulphuric and sulphurous acid vapours, and left charcoal. Another portion of the unchanged strong acid solution was placed over sulphuric acid in an exhausted receiver. In some hours it had by concentration become a soft white solid, apparently dry ; and after a longer period was hard and brittle. In this state it was deliquescent in the air, but in close vessels underwent no change in several months. Its taste was bitter, acid, and accompanied by an after metallic flavour, like that of cupreous salts. When heated in a tube at temperatures below 212°, it melted without any other change, and on being allowed to cool, crystaUized from centres, the whole ultimately becoming solid. When more highly heated, water at first passed off, and the acid assumed a slight red tint ; but no sulphurous acid was as yet pro- duced, nor any charring occasioned ; and a portion being dissolved and tested by muriate of baryta, gave but a very minute trace of free sulphuric acid. In this state it was probably anhydrous. Further heat caused a little naphthaline 1 48 Mr, Faraday on the mutual action of sulphuric acid to rise, the red colour became deep brown, and then a sudden action commenced at the bottom of the tube, which spread over the whole, and the acid became black and opaque. Continuing the heat, naphthahne, sulphurous acid, and char- coal were evolved ; but even after some time the residuum examined by water and carbonate of baryta, was found to contain a portion of the peculiar acid undecomposed, unless the temperature had been raised to redness. These facts establish the peculiarity of this acid, and dis- tinguish it from all others. In its solid state it is generally a hydrate containing much combustible matter. It is readily soluble in water and alcohol, and its solutions forms neutral salts with bases, all of which are soluble in water, most of them in alcohol, and all combustible, leaving sulphates or sulphurets according to circumstances. It dissolves in naph- thaline, oil of turpentine, and olive oil, in greater or smaller quantities, according as it contains less or more water. As a hydrate, when it is almost insoluble in naphthaline, it resembles the heavier substance obtained as before described, by the action of sulphuric acid on naphthaline, and which is the solid hydrated acid, containing a little naphthaline, and some free sulphuric acid ; whilst the lighter substance is a solution of the dry acid in naphthaline ; the water present in the oil of vitriol originally used being sufficient to cause a separation of a part, but not of the whole. 2. Salts formed by the peculiar acid with bases. These compounds may be formed, either by acting on the bases or their carbonates by the pure acid, obtained as already described; or the impure acid in solution may be used. and naphthaline, and on a new acid produced. 149 the salts resulting being afterwards freed from sulphates, by solution in alcohol. It is however proper to mention that another acid, composed of the same elements, is at the same time formed with the acid in question, in small, but variable proportions. The impure acid used, therefore, should be examined as to the presence of this body, in the way to be directed when speaking of the barytic salts ; and such specimens as contain very little or none of it should be selected. Potash forms with the acid a neutral salt, soluble in water and alcohol, forming colourless solutions. These yield either transparent or white pearly crystals, which are soft, slightly fragile, feel slippery between the fingers, do not alter by exposure to air, and are bitter and saline to the taste. They are not very soluble in water ; but they undergo no change by repeated solutions and crystallizations, or by long conti- nued ebullition. The solutions frequently yield the salt in acicular tufts, and they often vegetate, as it were, by spon- taneous evaporation, the salt creeping over the sides of the vessel, and running to a great distance in very beautiful forms. The solid salt heated in a tube gave off a little water, then some naphthaline ; after that a little carbonic and sulphurous acid gases arose, and a black ash remained, con- taining carbon, sulphate of potash, and sulphuret of potas- sium. When the salt was heated on platinum foil, in the air, it burnt with a dense flame, leaving a slightly alkaline sulphate of potash. Soda yields a salt, in most properties resembling that of potash ; crystalline, white, pearly, and unaltered in the air. 150 Mr. Faraday on the mutual action of sulphuric acid I thought that, in it, the metallic taste which frequently occurred with this acid and its compounds was very decided. The action of heat was the same as before. Ammonia formed a neutral salt imperfectly crystalline, not deliquescent, but drying in the atmosphere. Its taste was saline and cooling. It was readily soluble in water and alcohol. When heated on platinum foil it fused, blackened, burnt with flame, and left a carbonaceous acid sulphate of ammonia, which by further heat was entirely dissipated. Its general habits were those ' of ammoniacal salts. When its solutions, though previously rendered alkaline, were evapo- rated to dryness at common temperatures, and exposed to air, the salt became strongly acid to litmus paper. This however is a property common to all soluble ammoniacal salts, I believe, without exception. Baryta. It is easy by rubbing carbonate of baryta with solution of the impure acid, to obtain a perfectly neutral solution, in which the salt of baryta, containing the acid already described, is very nearly pure. There is in all cases an undissolved portion, which being washed repeatedly in small quantities of hot water, yields to the first portions a salt, the same as that in the solution. As the washings proceed, it is found, that the salt obtained does not burn with so much flame on platina foil, as that at first separated ; and the fifth or sixth washing will perhaps separate only a little of a salt, which when heated in the air, in small quantities, burns without flame in the manner of tinder. Hence it is evident that there are two compounds of baryta, which as they are both soluble in water, both neutral, and both combustible, and naphthaline y and on a new acid produced. 151 leaving sulphate of baryta, differ probably only in the quan- tity of combustible matter present, or its mode of combina- tion in the acid. It is this circumstance, of the formation of a second salt in small but variable quantities With, the first, which must be guarded against, as before mentioned, in the preparation of salts from the impure acid. It varies in quantity according to the proportions of materials, and the heat employed ; and I have thought that, when the naphthaline has been in large quantity, and the temperature low% the smallest quantity is produced. When the impure acid is used for the preparation of the salts now under description, a small portion of it should be examined by carbonate of baryta, as above, and rejected, if it furnish an important quantity of the flameless salt. These bodies may be distinguished from each other provi- sionally, as the flaming and the glowing salts of baryta, from their appearances when heated in the air. The latter is more distinctly crystaUine than the former, and much less soluble, which enabled me by careful and repeated crystallizations, to obtain both in their pure states. The flaming salt (that corresponding to the acid now under description ) when obtained by the slow evaporation of the saturated solution, formed tufts, which were imperfectly crystalline. When drops were allowed to evaporate on a glass plate, the crystalline character was also perceived ; but when the salt was deposited rapidly from its hot saturated solution, it appeared in the form of a soft granular mass. When dry, it was white and soft, not changing in the atmo- sphere. It was readily soluble in water and alcohol, but was 152 Mr. Faraday on the mutual action of sulphuric acid not affected by ether. Its taste was decidedly bitter. When heated in the air on platinum foil it burnt with a bright smoky flame, like naphthaline, sending flocculi of carbon into the atmosphere, and leaving a mixture of charcoal, sulphuret of barium, and sulphate of baryta. After being heated to 212° for some time, the salt appeared to be perfectly dry, and in that state was but very slightly hygrometric. When heated in a tube naphthaline was evolved ; but the substance could be retained for hours at a temperature of 500° F. before a sensible portion of naphtha- line had separated : a proof of the strength of the affinity by which. the hydro-carbon was held in combination. When a higher temperature was applied, the naphthaline, after being driven off, was followed by a little sulphurous acid, a small portion of tarry matter, and a carbonaceous sulphate and sulphuret were left. This salt was not affected by moderately strong nitric or nitro-muriatic acid, even when boiled with them ; and no precipitation of sulphate took place. When the acids were very strong, peculiar and complicated results were obtained. When put into an atmosphere of chlorine, at common tem- peratures, it was not at all affected by it. Heat being applied, an action between the naphthaline evolved, and chlorine, such as might be expected, took place. When a strong solution of the pure acid was poured into a strong solution of muriate of baryta, a precipitate was formed, in consequence of the production of this salt. It was re-dissolved by the addition of water. The fact indicates that the affinity of this acid for baryta is stronger than that of muriatic acid. and naphthaline, and on a new acid produced. 15s The second, or glowing salt of baryta, was obtained in small crystalline groups. The crystals were prismatic, colourless, and transparent : they were almost tasteless, and by no means so soluble either in hot or cold water as the former salts. They were soluble in alcohol, and the solutions were perfectly neutral. When heated on platinum foil they gave but very little flame, burning more like tinder, and leaving a carbonaceous mixture of sulphuret and sulphate. When heated in a tube they gave off a small quantity of naphtha- line, some empyreumatic fumes, with a little sulphurous acid, and left the usual product. This salt seemed formed in largest quantity when one volume of naphthaline and two volumes of sulphuric acid were shaken together, at a temperature as high as it could be without charring the substances. The tint, at first red, became olive green ; some sulphurous acid was evolved, and the whole would ultimately have become black and charred, had it not been cooled before it had proceeded thus far, and immediately dissolved in water. A solution was obtained, which though dark itself, yielded, when rubbed with carbonate of baryta, colourless liquids; and these when evaporate^ furnished a barytic salt, burning without much flame, but which was not so crystalline as former specimens. No attempt to form the glowing salt from the flaming salt by solution of caustic baryta, succeeded. Strontia. The compound of this earth with the acid already described very much resembled the flaming salt of baryta. When dry it was white, but not distinctly crystalline ; it was soluble in water and alcohol ; not alterable in the air, but MDCCCXXVI. X 154 Mr. Faraday on the mutual action of sulphuric acid when heated burnt with a bright flame, without any red tinge, and left a result of the usual kind. Lime gave a white salt of a bitter taste, slightly soluble in water, soluble in alcohol, the solutions yielding imperfect crystalline forms on evaporation: it burnt with flame; and both in the air and in tubes, when heated, gave results similar to those of the former salts. Magnesia formed a white salt with a moderately bitter taste ; crystallizing in favourable circumstances, burning with flame, and giving such results by the action of heat as might be expected. Iron. The metal was acted upon by the acid, hydrogen being evolved. The moist protoxide being dissolved in the acid gave a neutral salt capable of crystallization. This by exposure to air slowly acquired oxygen, and a portion of per-salt was found. Zinc was readily acted upon by the acid, hydrogen evolved, and a salt formed. The same salt resulted from the action of the acid upon the moist oxide. It was mode- rately soluble in hot water, the solution on cooling affording an abundant crop of acicular crystals. The salt was white and unchangeable in the air ; its taste bitter. It burnt with flame, and gave the usual results by heat. Lead. The salt of this metal was white, solid, crystalline, and soluble in water and alcohol. It had a bitter metallic taste, with very little sweetness. The results by heat were such as might be expected. Manganese. The protoxide of this metal formed a neutral crystalline salt with the acid. It had a slightly austere taste. and naphthaline, and on a new acid produced. 165 was soluble in water and alcohol, and was decomposed by heat, with the general appearances already described. Copper. Hydrated per-oxide of copper formed an acid salt with the acid, and the solution evaporated in the air left radiated crystalline films. The dry salt when heated fused, burnt with flame, and exhibited the usual appear- ances. Nickel. The salt of this metal was made from the moist carbonate. It was soluble, crystalline, of a green colour, and decomposed by heat in the usual manner. In one instance an insoluble sub-salt was formed. Silver. Moist carbonate of silver dissolved readily in the acid, and a solution, almost neutral, was quickly obtained. It was of a brown colour, and a powerful metallic taste. By evaporation it gave a splendent, white, crystalline salt ; not changing in the air except when heated ; but then, burning with flame and ultimately leaving pure silver. When the solution of the salt was boiled for some time, a black insolu- ble matter was thrown down, and a solution obtained, which by evaporation gave abundance of a yellow crystalline salt. The changes which took place during the action of heat in the moist way were not minutely examined. Mercury. Moist proto-carbonate of mercury dissolved in the acid forming a salt not quite neutral, crystallizing feebly in the air, white, of a metallic taste, not deliquescent, and decomposed with various phenomena by heat. By re-solution in water or alcohol, and heat, a sub-salt of a yellow colour was formed. The moist hydrated per-oxide of mercury also dissolved in the acid, forming an acid solution, which by evaporation i'56 Mr, Farad aV on the Mui'Ual action of sulphuric acid gSlv'fe ^ yellowish deliquescent salt, decdiflposed by heat, burning in the air, and entirely volatile. 3. Analysis of the acid and salts^. When solution of the pure acid was subjected to the Voltaic battery, oxygen and hydrogen gases Were evolved in thdr pure state : no solid matter separated, but the solutibh became of a deep yellow colour at the positive pole, occa- sioned by the evolution of fre6 sulphuric acid,' which re-acted upon the hydro-carbon. A solution of the bai^tic salts gave similar results. ■ The analytical experiments upon the composition of this acid and its salts were made principally with the compound of baryta. This was found to be very constant in composi- tion, could be obtained anhydrous at moderate temperatures, and yet sustained a high temperature before it suffered any change. A portion of the piite salt was prepared and dried for some hours on the sand bath, at a'tempei'ature aboiit 212°. Known weights were then heatied in a platinum crucible fo dissipate and burn off the combustible matter; and the residuum being moistened with sulphuric acid to decompose any sulphuret of barium formed, was heated to convert it int6 a fiiire sulphate of baryta. The results obtained were very constant, and amounted to 41.714 of sulphate of baryta per cent, of salt used, equivalent to 27.57 baryta per cent. Other portions of the salt were decomposed by being heated in a flask with strong nitro-muriatic acid, so as to liberate the sulphuric acid from the carbon and hydrogen pi-esent, and yet retain it in the state of acid. Muriate of and naphtfhaline, und on a new acid produced. 157 baryta was then added, the whole evaporated to dryness, heated red-hot, washed with dilute muriatic acid to remove the baryta uncombined with sulphuric acid, and the sulphate collected, dried, and weighed. The results were inconstant; but the sulphate of baryta obtained, always much surpassed that furnished by the former method. Judging from this circumstance that the jsulphuric acid in the salt was more than an equivalent for the baryta present, many processes were devised for the determination of its quantity, but were rejected in consequence of difficulties and imperfections, [aris- ing, principally, from the presence and action of so much carbonaceous matter. The following was ultimately adopted. A quantity of per-oxide of copper was prepared by heating copper plates in air and scaHng them. A sufficient quantity of pure muriatic and nitric acids were provided, and also a specimen of pure native carbonate of baryta. Seven grains of the salt to be examined were then mixed with seven grains of the pulverized carbonate of baryta, and afterwards witii 312 grains of the oxide of copper. The mixture being, put into a glass tube was successively heated throughout its Onass, the gas liberated being passed through a mixture of baryta water and solution of muriate of baryta. It was found that no sulphurous or sulphuric acids came off', or indeed sulphur in any state. The contents of the tube were then dissolved in an excess of nitric and muriatic acids, above that required to take up all that was soluble ; and a little solution of muriate of baryta was added for the sake of greater certainty. A portion of sulphate of baryta remained undis- solved, equivalent to the sulphuric acid of the salt experi- mented upon, with that containedaccidentally in the oxide of 158 Mr, Faraday on the mutual action of sulphuric acid copper acids, &c. This sulphate was collected, washed, dried and weighed. Similar quantities of the carbonate of baryta and oxide of copper were then dissolved in as much of the nitric and muriatic acids as was used in the former experi- ment ; and the washings and other operations being repeated exactly in the same way, the quantity of sulphate of baryta occasioned by the presence of sulphuric acid in the oxide, acids, &c. was determined. This, deducted from the weight afforded in the first experiments, gave the quantity produced from the sulphuric acid actually existing in the salt. Expe- riments so conducted gave very uniform results. The mean of many, indicated 8.9 grains of sulphate of baryta for 10 grains of salt used, or 89 grains per cent, equivalent to SO. 17 of sulphuric acid for every 100 of salt decomposed. In the analytical experiments, relative to the quantity of carbon and hydrogen contained in the salt, a given weight of the substance being mixed with per-oxide of copper, was heated in a green glass tube. The apparatus used consisted of Mr. Cooper's lamp furnace, with Dr. Prout's mercurial trough ; and all the precautions that could be taken, and which are now well known, were adopted for the purpose of obtaining accurate results. When operated upon in this way, the only substances evolved from the salt, were car- bonic acid and water. As an instance of the results, s-S grains of the salt aflforded 11.74 cubic inches of carbonic acid gas, and 0.9 of a grain of water. The mean of several experiments gave 32.93 cubic inches of carbonic acid gas, and 2.589 grains of water, for every 10 grains of salt decomposed. On these data, 100 grains of the salt would yield 329.3 and naphthaline, and on a new acid produced. 159 cubic inches of carbonic acid, or 153.46 grains, equivalent to 41.9 grains of carbon, and 25.89 grains of water, equivalent to 2.877 grains of hydrogen. Hence 100 grains of the salt yielded Baryta - - 27.57 - - 78 Sulphuric acid - 30.17 - - 85.35 Carbon - - 41.90 - 118.54 Hydrogen - 2,877 - - 8.13 102.517 In the second numerical column the experimental results are repeated, but increased, that baryta might be taken in the quantity representing one proportional, hydrogen being unity: and it will be seen that they do not differ far from the follow- ing theoretical statement. Baryta - 1 proportional - 78 Sulphuric acid 2 ditto - - - 80 Carbon - 20 ditto - - 120 Hydrogen - 8 ditto - - 8 The quantity of sulphuric acid differs most importantly from the theoretical statement, and it probably is that element of the salt, in the determination of which most errors are involved. The quantity of oxide of copper and of acids required to be used in that part of the analysis, may have introduced errors, affecting the small quantity of salt em- ployed, which when multiplied, as in the deduction of the numbers above relative to 100 parts, may have created an error of that amount. As there is no reason to suppose that during the combina- tion of the acid with the baryta any change in its proportions i6o Mr, Faraday on the mutual action of sulphuric acid takes place, the results above, minus the baryta, will repre* sent its composition : from which it would appear, that one proportional of the acid consists of two proportionals of sul- phuric acid, twenty of carbon, and eight of hydrogen ; these constituents forming an acid equivalent in saturating power to one proportional of other acids. Hence it would seem, that half the sulphuric acid present, at least when in combi- nation, is neutralized by the hydro-carbon ; or, to speak in more general terms, that the hydro-carbon has diminished the saturating power of the sulphuric acid to one half. This very curious and interesting fact in chemical affinity was however made known to me by Mr. Hennell of Apothecaries' Hall, as occurring in some other compounds of sulphuric acid and hydro-carbon, before I had completed the analysis of the present acid and salts ; and a similar circumstance is known with regard to muriatic acid, in the curious com- pound discovered by M. Kind, which it forms with oil of turpentine. Mr. Hennell is I believe on the point of offering an account of his experiments to the Royal Society, and as regards date they precede mine. It may be observed, that the existence of sulphuric acid in the new compounds, is assumed, rather than proved ; and that the non-appearance of sulphurous acid, when sulphuric acid and naphthaline act on each other, is not conclusive as to the non-reaction of the bodies. It is possible that part of the hydrogen of the naphthaline may take oxygen from one of the proportions of the sulphuric acid, leaving the hypo- sulphuric acid of Welter and Gay Lussac, which with the hydro-carbon may constitute the new acid. I have not time at present to pursue these refinements of the subject, or to and naphthaline y and on a new acid produced. 161 repeat the analyses which have been made of naphthahne, and which would throw light upon the question. Such a view would account for a part of the overplus in weight, but not for the excess of the sulphuric acid obtained, above two proportionals. The glowing salt of baryta was now analysed by a process similar to that adopted for the flaming salt. The specimen operated upon was pure, and in a distinctly crystalline state. It had been heated to about 440° F. for three hours in a metallic bath. Ten grains of this salt exposed to air for 40 hours increased only 0.08 of a grain in weight. These when converted into sulphate of baryta by heat and sulphuric acid, gave 4.24 grains. Seven grains by carbonate of baryta, oxide of copper, heat, &c. gave 6.02 grains of sulphate of baryta : hence 10 grains of the salt would have afforded 8.6 grains of the sulphate equivalent to 2.915 grains of sulphuric acid. Five grains when heated with oxide of copper gave 16.68 cubic inches of carbonic acid gas, equal to 7.772 grains, and equivalent to 2.12 grains of carbon. The water formed amounted to 1.2 grains equivalent to 0.133 of a grain of hydrogen. From these data, 100 grains of the salt would appear to furnish Baryta - 28.03 - 78 or 1 proportional. Sulphuric acid 29.13 - 81.41 nearly two proportionals. Carbon - 42.40 - 118. approaching to 20 ditto. Hydrogen 2.66 - 7.4 or 7.4 proportionals. 102.22 results not far different from those obtained with the former salt. MDCCCXXVI. Y i62 Mr. Faraday on the mutual action of sulphuric acid, &c. I have not yet obtained sufficient quantities of this salt in a decidedly crystalline state to enable me satisfactorily to account for the difference between it and the flaming salt. Attempts were made to form similar compounds with other acids than the sulphuric. Glacial phosphoric acid was heated and shaken in naphthaline, but without any particular results. A little water was then used with another portion of the materials, to bring the phosphoric acid into solution, but no decided combination could be obtained. Muriatic acid gas was brought into contact with naphthaline in various states, and at various temperatures, but no union could be effected either of the substances or their elements. Very strong solution of potash was also heated with naph- thaline, and then neutralized by sulphuric acid; nothing more however than common sulphate of potash resulted. As the appropriation of a name to this acid will much facilitate future reference and description, I may perhaps be allowed to suggest that of sulpho-naphthalic acid, which suffi- ciently indicates its source and nature without the inconve- nience of involving theoretical views. Royal Institution, January lo, i8z6. c 163 : XII. On the nervous circle which connects the voluntary muscles with the brain. By Charles Bell, Esq. Communicated by the President, January 25, 1826. Read February 16, 1826. JLn the Papers which I have had the honour of addressing to the Society^on the arrangement of the nerves of the human body, I have proceeded upon a comparison of the nerves of the spinal marrow^ with the nerves of the en- cephalon. It was shown that the former were compounded of fila- ments possessing different powers, and that each nerve, having several properties or endowments collected within itself, proceeded to its destination without intricacy. Unless we had discovered the composition of the roots of these nerves, we should have continued to suppose that one nerve was simple in its structure, and yet capable of bestow- ing the very different properties of motion and sensation. But having satisfied myself that the roots of the spinal nerves had distinct powers, I followed up the columns of the spinal marrow ; and with a knowledge of the composition of these nerves as a key, I examined the different properties of the nerves of the encephalon. Here, in the head, the nerves arise simply, and diverge to their destinations without the close compact or union which the spinal nerves form ; and accordingly, the anatomy of these nerves of the brain affords satisfactory proof of their uses or functions. I am about to 164 Mr. Bell on the nervous circle which connects show that every muscle has two nerves, of different proper- ties, supplied to it. This I could not have ascertained by examination of the spinal nerves alone, because of the inti- mate union of all their fibres ; I had recourse therefore to the nerves of the head. By prosecuting those enquiries, which led to the distinction of the different classes of nerves, I hope now to demonstrate — that where nerves of different functions take their origin apart and run a different course : two nerves must unite in the muscles, in order to perfect the relations betwixt the brain and these muscles. It may be in the recollection of the Society, that my first Paper showed the difference of the nerves of the face ; by dividing one nerve, sensation was destroyed, whilst motion remained ; and by dividing the other, motion was stopped, whilst sensibility remained entire. Other parts of the nervous system since that time have engaged my attention ; and it is only now that I am able to make full use of the facts announced in my first Paper, which were indeed expected to lead to further improvement of our knowledge of the animal oeconomy . When I distinguished the two classes of nerves going to the muscles of the face, and divided the motor nerve, and when the muscles were de- prived of motion by this experiment, the natural question suggested itself — of what use are the nerves that remain entire ? For a time I believed that the fifth nerve, which is the sensitive nerve of the head and face, did not terminate in the substance of the muscles, but only passed through them to the .skin; and I was the more inclined to this befief on ob- serving, that the muscular parts when exposed in surgical the voluntary muscles with the brain, 165 operations did not possess that exquisite sensibility which the profusion of the sensitive nerves w^ould imply, or which the skin really possesses. Still dissection did not authorise this conclusion. I traced the sensitive nerves into the substance of the muscles : I found that the fifth pair was distributed more profusely to the muscles than to the skin ; and that estimating all the nerves given to the muscles, the greater proportion belonged to the fifth or sensitive nerve, and the smaller proportion to the seventh or motor nerve. On referring to the best authorities, as Meckel,* and my excellent preceptor Monro, the extre- mities of the fifth were described by them as going into the muscles, so that of this fact there cannot be a doubt. Having in a former Paper demonstrated that the portio dura of the seventh nerve was the motor of the face, and that it run distinct from the sensitive nerve, the fifth, and observing that they joined at their extremities, or plunged together into the muscles, I was nevertheless unwilling to draw a con- clusion from a single instance ; and therefore cast about for other examples of the distribution of the muscular nerves. It was easy to find motor nerves in combination with sensitive nerves, for all the spinal nerves are. thus composed; but we wanted a muscular nerve clear in its course, to see what alliance it would form in its ultimate distribution in the muscle. I found in the lower maxillary nerve the example I required. The fifth pair, from which this lower maxillary nerve comes, as I have elsewhere explained, is a compound nerve; that is to say, it is composed of a nerve of sensation, and a ♦ Meckel de quinto pare nervorum cerebri. 166 Mr, Bell on the nervous circle which connects nerve of motion. It arises in two roots, one of these is the muscular nerve, the other the sensible nerve ; on this last division the Gasserian ganglion is formed. But we can trace the motor nerve clear of the ganglion and onward in its course to the muscles of the jaws, and so it enters the tem- poral masseter pterygoid and buccinator muscles. If all that is necessary to the action of a muscle be a nerve to excite to contraction, these branches should have been unaccompanied ; but on the contrary, I found that before these motor nerves entered the several muscles, they were joined by branches of the nerves which came through the Gasserian ganglion, and which were sensitive nerves. I found the same result on tracing motor nerves into the orbit, and that the sensitive division of the fifth pair of nerves was transmitted to the muscles of the eye, although these muscles were supplied by the third, fourth, and sixth nerves. A circumstance observed on minute dissection remained unexplained, — when motor nerves are proceeding to several muscles they form a plexus ; that is, an interlacement and exchange of fibres takes place. The muscles have no connection with each other, they are combined by the nerves ; but these nerves, instead of passing betwixt the muscles, interchange their fibres before their dis- tribution to them, and by this means combine the muscles into classes. The question therefore may thus be stated : why are nerves, whose office it is to convey sensation, pro- fusely given to muscles in addition to those motor nerves which are given to excite their motions ? and why do both classes of muscular nerves form plexus ? To solve this question, we must determine whether muscles the voluntary muscles with the brain, 167 have any other purpose to serve than merely to contract under the impulse of the motor nerves. For if they have a reflective influence, and if their condition is to be felt or perceived, it v^ill presently appear that the motor nerves are not suitable internuncii betwixt them and the sensorium. / shall first enquire, if it be necessary to the governance of the muscular frame, that there be a consciousness of the state or degree of action of the muscles ^ That vv^e have a sense of the condi- tion of the muscles, appears from this : that we feel the effects of over exertion and weariness, and are excruciated by spasms, and feel the irksomeness of continued position. We possess a power of weighing in the hand: — what is this but estimating the muscular force ? We are sensible of the most minute changes of muscular exertion, by which we know the position of the body and limbs, when there is no other means of knowledge open to us. If a rope-dancer measures his steps by the eye, yet on the other hand a blind man can balance his, body. In standing, walking, and running, every effort of the voluntary power, which gives motion to the body, is directed by a sense of the condition of the muscles, and without this sense we could not regulate their actions. If it were necessary to enlarge on this subject, it would be easy to prove that the muscular exertions of the hand, the eye, the ear, and the tongue, are felt and estimated when we have perception through these organs of sense ; and that without a sense of the actions of the muscular frame, a very principal inlet to knowledge would be cut off! If it be granted, that there must be a sense of the condition of the muscle, we have next to show that a motor nerve is 1^8 Mr, Bell on the nervous circle which connects not a conductor towards the brain, and that it cannot perform the office of a sensitive nerve. Without attempting to determine the cause, whether de- pending on the structure of the nervous cord, or the nature, or the source of the fluid contained, a pure or simple nerve has the influence propagated along it in one direction only, and not backwards and forwards ; it has no reflected opera- tion or power retrograde ; it does not both act from and to the sensorium. Indeed reason without experience would lead us to con- clude, that whatever may be the state, or the nature of the activity of a motor nerve during exertion, it supposes an energy proceeding from the brain towards the muscles, and precludes the activity of the same nerve in the opposite direction at the same moment. It does not seem possible therefore that a motor nerve can be the means of communi- cating the condition of the muscles to the brain. Expose the two nerves of a muscle ; irritate one of them, and the muscle will act ; irritate the other, and the muscle remains at rest. Cut across the nerve which had the power of exciting the musclfe, and stimulate the one which is undi- vided— the animal will give indication of pain ; but although the nerve be injured so as to cause universal agitation, the muscle with which it is directly connected does not move. Both nerves being cut across, we shall still find that by exciting one nerve the muscle is made to act, even days after the nerve has been divided; but the other nerve has no influence at all. Anatomy forbids us to hope that the experiment will be the voluntary muscles with the brain. 169 as decisive when we apply the irritants to the extremities of the divided nerves which are connected with the brain ; for all the muscular nerves receive more or less minute filaments of sensitive nerves, and these we can trace into them by the knife, and consequently, they will indicate a certain degree of sensibility when hurt. To expose these nerves near their origins, and before any filament of a sensitive nerve mingles with them, requires the operator to cut deep, to break up the bones, and to divide the blood-vessels. All such experiments are much better omitted ; they never can lead to satisfactory conclusions. Experience on the human subject most abundantly illus- trates these facts. For example : — a patient of mine having, by a tumour pressing the nerves of the orbit, lost the sensi- bility of the eye and eye-lids, she retained the motion of the eye-lids by the portio dura coming round externally and escaping the pressure which injured the other nerves. Here the course of sensibility backwards to the brain was cut off, while the course of volition was free ; she could not tell whether the eye-lid was open or shut, but being asked to shut the eye which was already closed, she acted with the orbicular muscle and puckered the eye-lids. When I touched the eye there was no winking, because the sensitive fifth pair had lost its power, although she could command the motion by voluntary exertion. In another instance, when the eye was insensible, touching the eye gave rise to a blush of redness and to inflammation, because the part was excited, but the muscles were not called into action : the relations which connect the sensibility of the eye with the motions of the eye and eyelid are established MDCCCXXVI. Z i7o Mr, Bell on the nervous circle which connects in the roots of the fifth and seventh in the brain ; the loss of function of the fifth nerve therefore interrupted the circle. Here too the motor nerve of the eye-lid was perfect, and the eye-lid readily acted under the influence of the will, but when the eye-lid was touched or pricked it communicated no sen- sation. Is this insensibility of a motor nerve owing to the course of its influence being from the brain, and not towards it ? When the nostril had lost its sensibility from an affection of the fifth pair, we could not excite sneezing ; when the tongue and cheek had lost sensibility, the morsel was per- mitted to remain between the tongue and the cheek until it was offensive, although the motions both of the tongue and the cheek were perfect. All these phenomena correspond with the experiments on animals. Now it appears the muscle has a nerve in addition to the motor nerve, which being necessary to its perfect function, equally deserves the name of muscular. This nerve however has no direct power over the muscle, but circuitously through the brain, and by exciting sensation it may become a cause of action. Between the brain and the muscles there is a circle of nerves ; one nerve conveys the influence from the brain to the muscle, another gives the sense of the condition of the muscle to the brain. If the circle be broken by the division of the motor nerve, motion ceases ; if it be broken by the division of the other nerve, there is no longer a sense of the condition of the muscle, and therefore no regulation of its activity.* * Thus led to conclude that there is motion in a circle, we nevertheless cannot adopt the hypothesis of circulating fluids. That a fluid does not proceed from the brain, we may learn from this ; that on touching the end of a motor nerve which the voluntary muscles with the brain. 171 We have noticed, that there is a plexus formed both on the nerves which convey the will to the muscles, and on the nerves which give the sense of the condition of the muscles. The reason of this I apprehend to be that the nerves must correspond with the muscles, and consequently with one another. If the motor nerve has to arrange the action of several muscles so as to produce a variety of motions, the combinations must be formed by the interchange of filaments among the nerves before they enter the muscles, as there is no connection between the muscles themselves. As the various combinations of the muscles have a relation with the motor nerves, the same relations must be established by those nerves which convey the impression of their combina- tions, and a similar plexus or interchange of filaments there- fore characterizes both. We have seen that the returning muscular nerves are associated with the nerves of sensibility to the skin, but they are probably very distinct in their endowments, since there is a great difference between conveying the sense of external impressions, and that of muscular action. In surgical operations the fact is forced upon our attention that the pain of cutting the skin is exquisite, compared with that of the muscles ; but we must remember that pain is a modification of the endowment of a nerve, serving as a guard to the surface, and to the deeper parts consequently. This has been some days separated from the brain, the muscle is excited as when the nerve was first divided. The property, however it may be defined, is therefore in the nerve. Our language might perhaps be made more precise if we used terms which implied the course of nervous influence, whether from or towards the brain ; but it will be difficult to express this without the aid of hypothesis. 172 Mr. Bell on the nervous circle which connects is further exemplified in the sensibility of the skin to heat ; whilst, on the contrary, a muscle touched with a hot or cold sponge during an operation, gives no token of the change of temperature but by the degree of pain. Many of the nerves which perform the most delicate ope- rations in the oeconomy , are not more sensible to pain than the common texture of the frame. The lower degree of sen- sibility to pain possessed by the muscles, and their insensi- bility to heat, is no argument against their having nerves which are alive to the most minute changes of action in their fibres. When the anatomist shall find both the portio dura of the seventh and the fifth going to the integuments of the head and face, he may naturally ask, why are there two nerves to the surface ? and he will probably reflect, that although the principal office of the nerves of the skin is to convey impres- sion to the sensorium, yet the influence of the mind is con- veyed to the surface. The condition of the mind in passion, for example, is as forcibly communicated to the skin as to the muscles themselves ; and therefore if a branch of the fifth be necessary to convey sensation from the surface to the sensorium, the seventh is necessary to the change of vascular action, and to the condition of the pores when affected by a cause proceeding from within, outwards. I feel a hesitation when I reason upon any other ground than on the facts of anatomy. Experiments are more apt to be misinterpreted ; and the very circumstance of a motor and the voluntary muscles with the brain. 1 73 sensitive nerve being generally combined together, affords a pregnant source of error. It is natural to suppose that the galvanic influence might be brought to bear on this subject ; but I may be permitted to suggest to any one who pursues it in this way, that it will be necessary to distinguish the effects produced by the nerve as a mere conductor, and when performing its living functions. The nerve, dead or alive, may convey the galvanic power like a wet cord; but if the nerve be in possession of its living property, a great deal will depend on the direction in which the galvanic fluid is transmitted. If it be transmitted against the course of the nervous influence, it will reach the muscles and act feebly, but the power of the nerve will not be exer- cised upon the muscles ; but if it be transmitted in the proper course towards the muscles the nerve itself will be excited, and its power propagated so as to produce violent action in the corresponding muscles. C 174 3 XIII. On the constitution o^ the atmosphere. By John Dalton, Esq. F, R. S. &c. Communicated January 12, 1826. Read February 24, 1826. 1 HE fact discovered by Boyle and Marriotte, that the space occupied by air is in the inverse ratio of the pressure, is one of great importance in the doctrine of elastic fluids. It may probably not be mathematically true in extreme cases ; but in those where the condensations and rarefactions do not exceed 50 or 100 times, there is reason to believe the above ratio is a very near approximation to the truth. Sir Isaac Newton has shown in the 23d prop, book ii. of the Principia, that if homogeneous particles of matter were endued with a power of repulsion in the inverse ratio of their central distances, collectively they would form an elastic fluid agreeing with atmospheric air in its mechanical proper- ties. He does not infer from this demonstration that elastic fluids must necessarily consist of such particles ; and his argument requires that the repulsive power of each particle terminate, or very nearly so, in the adjacent particles. From the scholium to this proposition, Newton was evidently aware of the difficulty of conceiving how the repulsive action of such particles could terminate so abruptly as his supposition demands ; but in order to show that such cases exist in nature, he finds a parallel one in magnetism. Whatever we may think of the constitution of an elastic fluid, it is clear, that for the purpose of ascertaining its mecha- Mr. Dalton on the constitution of the atmosphere, 1 75 nical effects, we may safely adopt the above hypothesis within the fore-mentioned limits of condensation and rarefaction. The existence of elastic fluids totally different from atmo- spheric air in their chemical nature, but agreeing with it in mechanical properties, was unknown in Newton's time. Such fluids are now known to exist ; they may be mixed together, and, in case no obvious chemical action ensues, they are found to occupy the same space after as before mixture, and in due time to be uniformly diffused through the space the mixture occupies, whatever may be the difference of their volumes and specific gravities : and such mixtures have all the mechanical properties of simple elastic fluids, as the atmosphere itself evinces, which is a mixture of at least four such elastic fluids. Whether the uniform diffusion of elastic fluids through each other is occasioned by the repulsion of the elementary particles of the same kind, which appears to force them through most bodies, as well solid and liquid as aerial, except glass and the metals ; or whether it is caused by attraction or chemical affinity, may be doubted. Difficulties attend both views. I have long been inclined to adopt the former notion as most consistent with the phenomena. According to this view the particles of any elastic fluid (A) are endued with repulsion to each other by the Newtonian law above stated ; also those of any other (B) repel each other in like manner ; but the particles of (A) do not repel those of (B), or rather are inelastic in regard to them. Such mixture must evidently possess the mechanical law of condensation which the atmosphere possesses, and which Newton's imaginary homogeneous fluid possesses. 176 Mr. Dalton on the constitution of the atmosphere. All our ordinary experiments are limited to given volumes of gases which are considered of equal densities and tempe- ratures throughout the volumes ; but this is not the case when the volume is large, and extended in a direction per- pendicular to the horizon ; such, for instance, as a cylindrical column of the atmosphere of the altitude of several miles. The density in such vertical columns diminishes nearly in geometrical progression to equal intervals of ascent, and the temperature diminishes nearly in arithmetical progression, or in direct proportion to the ascent. When we observe the diffusion of two gases (A) and (B) through each other in small limited volumes, such as in our ordinary experiments, we may ascribe it on the one hand to the mutual attraction of the particles of (A) and (B); or on the other, to the repulsion of the particles of (A) for each other, and their non-repulsion of those of (B); and vice versa. The effect would seem to be precisely the same on both views. But it is not so when we consider a vertical atmo- spherical column of mixed gases. Here the two views display their difference in a striking manner. An exposition of the results of two indefinitely long per- pendicular columns of any given gases (A) and (B) being mixed together, having never yet been laid before the philo- sophical public according to either opinion, I apprehend it may be of service to the advancement of knowledge on this interesting subject to draw attention to the following con- siderations. Let A and B be two equal cylindrical tubes placed in contact and perpendicular to the horizon, of indefinite length, closed at the bottom and open at the top. Let the tube A have Mr. Dalton on the constitution of the atmosphere. 177 an atmosphere of hydrogen gas in it, so as that it would support the mercury in the barometer at go inches. Let the tube B have an atmosphere of carbonic acid gas also capable of supporting 30 inches of mercury. Now supposing it pos- sible for the atmosphere to be for a few moments of uniform density throughout the column, and that density the same as at the surface of the earth, the height of the hydrogen atmosphere would be about 66 miles, and that of the carbonic acid about 3.3 miles ; or the heights would be in the ratio of so to 1 nearly. Afterwards, when the atmospheres were expanded to their natural extent, equal elasticities of the two gases would also be at altitudes as 20 to 1 ; that is, if at two miles of elevation the carbonic acid atmosphere supported 15 inches of mercury, that of hydrogen would support the same at 40 miles elevation. These are positions too obvious to be insisted upon. Conceiving now the atmospheres to have acquired their perfect equilibrium, or to be at rest in the respective columns, let numerous air-tight horizontal partitions be imagined across both tubes at equal intervals •from the ground upwards. These intervals may be either small, as a foot, or larger, as a mile, as may suit our purpose. Let now a communication be opened between each two horizontal portions of the tubes, either by a perforation or a small tube, as represented in the annexed figure, ati, s, 3,4, &c. Then it is well known that the two gases would inter- mix, and finally obtain such equilibrium, that one half of the gas at first in each division would pass into the opposite division, and the other half remain where it was. Hence, the whole weight of gases in each whole tube would be still the MDCCCXXVI. 2 A 1 78 Mr. Dalton on the constitution of the atmosphere. same as before, namely, 30 inches of mercury ; half of which in each tube would be carbonic acid, and the other half hydrogen. Very great differences would be found in the proportions of the two gases in ascending, viewing them either in regard to volume or to weight. In the lowest division, or No. 1 , we should find equal volumes of carbonic acid and hydrogen. At the height of two miles, we should find about one volume of carbonic acid mixed with two of hydrogen ; at the height of four miles, the carbonic acid would be to the hydrogen as one to four, nearly ; and at the height of 40 miles, there would probably be no carbonic acid at all in either tube, but the hydrogen would there be of one half the density it was in No. 1. Above this, or above the limits of the carbonic acid atmosphere, wherever it might be, there would be nothing but hydrogen gas in each tube up to the limits of the hydro- gen atmosphere. The Hmits of the atmosphere having been mentioned, it may be proper to observe, that on the hypothesis of the density of any atmosphere diminishing in geometrical pro- gression to intervals of ascent in arithmetical progression, every atmosphere must be unlimited, or of infinite extent. But if any atmosphere is constituted of particles on the New- tonian hypothesis, it is obvious that such atmosphere must have a limit ; this limit will exist where the repulsion of two particles becomes equal to the weight of one of them. We have no data from which to determine the absolute height above the surface of the earth to which any one atmosphere can ascend ; but we can form a pretty accurate comparison of the relative heights to which two atmospheres Mr. Dalton on the constitution of the atmosphere. 179 would ascend, especially if the relative weights of their atoms be known. For instance ; we know that the diameter of an elastic particle of carbonic acid is nearly, or exactly, the same as that of a particle of hydrogen under the same pressure ; also that their weights are as 20 to 1. At two miles elevation, the elasticity of an atmosphere of carbonic acid gas is diminished one half ; and- at 40 miles elevation, that of hydrogen is diminished one half. Now^ let it be supposed that at 30 miles elevation the carbonic acid atmosphere ceases to exist, or ter- minates, at which elevation its elasticity must be according to the geometrical progression, nearly ^^qqq ; then, by the same law, the elasticity of the hydrogen atmosphere must be 33300 at the height of 1 5 x 40 == 600 miles ; also the diameters of the particles of the two gases are still equal at those eleva- tions, because they vary as the cube roots of the elasticities inversely ; that is, if the diameters of the particles of carbonic acid and hydrogen at the surface of the earth be denoted by 1, that of carbonic acid at 30 miles will be represented by ^v/iJooo", and that of hydrogen at 600 miles elevation will also be V 3 3000 . But by hypothesis, this distance is capable of supporting a weight as 20 (namely the weight of one atom of carbonic acid) ; the hydrogen atmosphere therefore must be further elevated till it is capable of supporting a weight only as 1 (namely, the weight of an atom of hydro- gen) ; this will take place when the elasticity is still further diminished in the ratio of the cube of 20 to the cube of 1, or 8000 to 1. Hence, we shall have to extend the atmosphere about 13 X 40 = 520 miles further before it can terminate, or to the height of 1 120 miles. In this estimate we have not i8o Mr, D ALTON on the constitution of the atmosphere taken into consideration the variable force of gravity. At the height of 1400 miles the force of gravity is reduced one half, nearly ; on this account the elevation of the hydrogen atmo- sphere will be increased between 1 and 2 hundred miles more, so as to make it amount to twelve or thirteen hundred miles. The variation of temperature in ascending does not materially affect our views. vii^i^Him Thus it appears that upon the assumption ,we have made, the hydrogen atmosphere must be 40 times the altitude of the carbonic acid atmosphere. If we had assumed the utmost height of the carbonic acid atmosphere less than 30 miles, the disproportion of the two heights would have been still greater ; and if more than 30 miles, it would have been less ; but in this case the absolute difference would be greater. If it be true that atmospheres have limits, or certain degrees of rarefaction beyond which they cannot be extended, it will produce certain modifications in the mixtures of the two gases in our tubes A and B, which will now require con- sideration. Suppose the cell 1000 to be that at the summit of the hydrogen column A, or where the hydrogen atmosphere terminated before any communication was made with the column B. Then, on opening the communication of that cell with the corresponding one of B, one half of the gass would flow out as usual ; but the two cells, instead of being filled with the dilated gas, would only be half filled with it. The gas would fill the lower half of each cell, pressing upon the lower partition, and the upper half would exist as a void. The same remark would apply, but in a less degree, to the inferior cells 999, 998, &c. and it would not be till a descent Mr. Dalton on the constitution of the atmosphere. 181 of 40 miles that the gas of one cell would be adequate to fill two cells, making the density in each the same as that in No. 1000 before the communication. In all that interval of 40 miles the continuity of the atmosphere would be inter- rupted, each cell having a partial void, and the partition having a pressure on it from above, and none beneath. In like manner it might be shown that the carbonic acid atmo- sphere, were it alone, and subsequently made to communicate with empty cells, would be two miles below the summit of the atmosphere before one cell of gas could fill two cells.* After a complete equilibrium of intercourse had taken place between every two adjacent cells, let us next conceive all the horizontal partitions to be withdrawn from the two tubes, and consider what results will ensue. It is evident the descent of the upper part of the hydrogen column in each tube would be immediate, as there would be vacuous places to fill up in it. The same would take place with the carbonic acid column ; but the great body or weight of the mixed atmospheres would remain unchanged, except a slight condensation. The column of hydrogen in each tube would support 1 5 inches of mercury, and would in all respects resemble the upper half of the first column. A, of hydrogen gas, that supported 30 inches, excepting a slight difference occasioned by distance from the earth and temperature ; and the same may be observed of the carbonic acid column in each tube. But would this constitution of the mixture be • Query, might not the absolute height of an atmosphere of carbonic acid gas (or any other) be found, by perfectly exhausting a tall receiver, then letting in a small given portion of the gas, and finding by some chemical test that the gas existed in the lower but not in the upper portion of the receiver ? i82 ikfr. D ALTON on the constitution of the atmosphere. permanent ? Would a mixed atmosphere, which in fact as a whole, consisted of equal weights of carbonic acid and hydro- gen, continue to exhibit at the surface of the earth equal volumes only in mixture ? Or, on the other hand, would not the whole be wrought up in due time into one uniform com- position in all its extent, of 20 volumes of hydrogen with one of carbonic acid, as many suppose to be the nature of the earth's atmosphere with regard to its component parts ? Before these questions are discussed we shall put the case in a different form : suppose a mixture of 20 volumes of hydrogen and one volume of carbonic acid (that is equal weights of each ) , were put into a large reservoir under the constant pressure of 30 inches of mercury, and from this reservoir were passed by means of a stop-cock into the inde- finite perpendicular tube. A, perfectly void, till such time as the equilibrium between the reservoir and the tube was established : query, what would be the final arrangement of the two gases in the tube ? I believe it will be allowed by all, that the final arrangement of the mixture of gases will be precisely, the same in this case as in the one previously stated, whatever that arrangement may be. Now I apprehend it is demonstrable, from what we know of the nature of mixed gases, that each of the two gases would be disposed just the same as if the other was not present. They would be mixed in equal volumes at the earth's surface ; the carbonic acid would rapidly diminish in density in ascending, and terminate perhaps at 28 or 30 miles of elevation ; the hydrogen would slowly diminish in den- sity, and terminate perhaps at 11 or 12 hundred miles of elevation. Mr. Dalton on the constitution of the atmosphere, 183 The arguments in support of this notion may be derived from the following facts : 1st. When two gases, not having a manifest chemical action upon each other, are put into a vessel of small limited capacity, they are found in a short time to be uniformly diffused through the capacity of the vessel, whatever be their proportions. 2d. Let a bottle, having its air exhausted, be half filled with water, and the other half with a mixture of equal volumes of two gases, suppose hydrogen and carbonic acid ; then let an air-tight stopper be applied, and the contents of the bottle be duly agitated. The carbonic acid will be found equally diffused through the whole capacity of the bottle, the same in the water as out of it ; but the hydrogen in the water will only be ■— or /^ of the density of that above the water. In this case each gas will be arranged, both within and without the water, precisely the same as if it was the only gas present. And if a third gas could afterwards be introduced into the bottle in hke manner, it would take its place in and out of the water independently of the other two ; and so on with any number. No pressure of any one gas on the surface of the water can confine another gas in the water ; it must be a pressure arising from the same gas. 3d. If a portion of ether, alcohol, &c. be put into a bottle, and it be close corked, the vapour will ascend and fill the bottle, whatever air be present ; its quantity and force will be the same whether there be any air, or none, being entirely regulated by the temperature. From these three facts, but more especially from the two last, it appears to me as completely demonstrated as any 184 Mr. Dalton on the constitution of the atmosphere, physical principle, that whenever two or more such gases or vapours as we have been describing are put together, either into a limited or unlimited space, they will finally be arranged each as if it occupied the whole space, and the others were not present ; the nature of the fluids and gravi- tation being the only efficacious agents. We may now apply this doctrine in considering the earth's atmosphere, on the supposition of its being in a quiescent state. The gases constituting it are azotic and oxygenous chiefly, a very small proportion of carbonic acid, and a small proportion of aqueous vapour. If we assume the weight of the atmosphere = 30 inches of mercury, and neglect the carbonic acid and aqueous vapour as inconsiderable in weight, we shall have ^^ of 30 = 6.3 inches for the weight of the oxygenous atmosphere, and -^-^ of 30 = 23.7 inches for the weight of the azotic atmosphere. For the weights of the whole atmospheres on this view are proportional to the vo- lumes found at the surface of the earth, and totally inde- pendent of their specific gravities. The weight of the aqueous vapour atmosphere is variable, and may be on an average = ,4f of an inch of mercury, and that of carbonic acid = .03 of an inch of mercury. The limit of altitude in a full atmosphere (of 30 inches mercury ) of oxygen gas being assumed at 45 miles, that of an atmosphere of the same gas of 6.3 inches of mercury will be found by calculation on the above principles to be about 38 miles, the atom of oxygen being 7 ; and that of azotic gas of 23.7 inches weight will be found 54 miles, if the atom of azote be taken as 5 ; but if the atom of azote be double this weight, as is supposed by many, but I think without Mr. D ALTON on the constitution of the atmosphere. 185 sufficient reason, then the height of the azotic atmosphere will be only 44 miles. The very fine and attenuated carbonic acid atmosphere must ascend to the height of 10 miles, if a full atmosphere of this gas ascend to 30 miles ; and that of steam or aqueous vapour to the height of 50 miles, allowing the specific gravity of steam to be .625, and the weight of its atom to be 8. It may be worth while to contrast this view of the consti- tution of the atmosphere with the only other one, as far as I know, that has been entertained. According to one view. 1. The volumes of each gas found at the surface of the earth are proportional to the whole weights of the respective atmo- spheres. Weight of atmosphere. Azote - = ^ = 79 Oxygen - — loo 21 Aqueous vap. = -^ — 1.33 Carbonic acid — ~ = .10 101.43 According to the other view. 1. The volume of each gas found at the surface of the earth multiplied by its specific gravity J is proportional to the whole weight of the respective atmosphere. sp. gr. Weight of atmosphere. Azote - = ^ X .97 = 16.6 Oxygen =r^xi.ii = 23.3 Aque. va. = -i- X .625 = 0.83 Car. acid =i~-x 1.53 = 0.15 100.88* * In order to show the ratios more completely we have assumed the two compound atmospheres differing a little in the total weights. MDCCCXXVI. sB iS6 Mr. Dalton on the constitution of the atmosphere. According to one view. 2. The altitude of each atmo- sphere differs from that of every other, and the proportions of each in the compound atmo- sphere gradually vary in the ascent. 3. When two atmospheres are mixed, they take their places according to their specific gra- vity, not in separate strata, but intermixedly. There is however a separate stratum of the speci- fically lighter atmosphere at the summit over the other. According to the other view. 2. The altitude of each atmo- sphere is the same, and the pro- portion of each in the compound atmosphere is the same at all elevations. 3. When two atmospheres are mixed, they continue so, without the heavier manifesting any dis- position to separate and descend from the lighter. All that we have said hitherto has been relating to quiescent atmospheres, or such as are in a state of perfect equilibrium. How the case would be with regard to the earth's atmo- sphere, such as it actually is, in a state of continual motion and agitation greater or less in all its parts, it is not very easy to ascertain ; and it is besides rather a question to be decided by experiment and observation than by any theory. I have a series of observations made on this subject ; but as they will require to be submitted in a considerable detail, I shall reserve them as a sequel to this essay on some future occasion. Mr. D ALTON on the constitution of the atmosphere, *i87 -*- lOOO — 999 =j= 998 = = 997 = = 6 5 — ^ — 3 r -j- 1 B From the Press of W. NICOL, Cleveland-row, St, James's. 0 Pfay»ic»J If Applied S^ PLEASE DO NOT REMOVE CARDS OR SLIPS FROM THIS POCKET UNIVERSITY OF TORONTO LIBRARY