f= a Ndechet. seeh?? nplotedet. sagen pemet Ale adel ee ees he Re aegeaat seb ah bar hs abe ) Leet pays SINT 11 eet et Teehe bet PTHSREPND Se. tears eed. aap ones a Sorthales ey eprerniat OM Era Selstatets ( saheeretg te eh eat eh at ‘i Hs : i + he il ion Hea | tle aga ts ied Marna i hike % ee ti fey wake g Ie rm) ii deaace - arate ah eas) hy Metall Cera i ey Hk S2z4__—C, : & we/ Cas AMERICAN ACADEMY ARTS AND SCIENCES. NEW SERIES. VOLox.— PARTI. CAMBRIDGE AND BOSTON: WELCH AND BIGELOW. METCALF AND DAKIN. 1868. . CM hk CAN A CAD EM OF ARTS AND SCIENCES. NEW SERIES. VOL, X.-PART. VW. LIBRARY NEW YORK BOTANICAL GARDEN CAMBRIDGE AND BOSTON: WELCH AND BIGELOW. METCALF AND DAKIN. 1868. CONPENTS OF PART 1: F PAGE I. Catalogue of Auroras observed, mostly at Cambridge, Mass., since the year 1838. By JoserH Loverine. : : : : 5 : PN Une : - 4 Pid ii II. On the Periodicity of the Aurora Borealis. By Josepn Lovertne. : 5 oe OFFICERS OF THE AMERICAN ACADEMY, FOR THE YEAR BEGINNING MAY, 1867. President. ASA GRAY. Vice-President. GEORGE T. WILLIAM B. ROGERS. CHAUNCEY WRIGHT. JOHN C. LEE. FRANK H. STORER. STANDING JOSEPH LOVERING, JOSIAH P. COOKE, WOLCOTT GIBBS, WILLIAM B. ROGERS, FRANK H. STORER, . JOSEPH WINLOCK, MORRILL WYMAN. JOSEPH LOVERING, CHARLES W. ELIOT, JEFFRIES WYMAN. JOHN BACON, JOHN B. HENCK, CHARLES PICKERING. . ASA GRAY, ex-officio. JOHN C. LEE, “ y THOMAS T. BOUVE. CHARLES E. WARE, . CHARLES J. SPRAGUE. Class 1. JOHN B. HENCK, THOMAS HILL, JOSEPH LOVERING. BIGELOW. Corresponding Secretary. Recording Secretary. Treasurer. Librarian and Cabinet-Keeper. COMMITTEES. Rumford Committee. | ~ Committee of Publication. ) - Committee on the Library. Auditing Commitiee. fommittee of Finance. Councit. Class 2. LOUIS AGASSIZ, CHARLES PICKERING, JEFFRIES WYMAN. Class 3. GEORGE E. ELLIS, ANDREW P. PEABODY, ROBERT C. WINTHROP. ———— = A / AUG 7 = 1993! urn MEMOIRS OF THE AMERICAN LIBRARY NEW york BOTANICAL GARDEN ACADEMY. Ie Catalogue * of Auroras observed, mostly at Cambridge, after the year 1838. » By JOSEPH LOVERING, HOLLIS PROFESSOR OF MATHEMATICS AND NATURAL PHILOSOPHY IN HARVARD COLLEGE. Cambridge, 1888. “1 Feb. 21. Brilliant Aurora. A light began to appear in the north at 8": large streamers crossed the heavens. At 10%, they were ar- ranged in vertical arcs, streaming up nearly to the zenith and concentrating in the northern horizon. Afterwards, their upper extremities assumed the color of brilliant scarlet. At 11%, the streamers were agitated, the light faded and flashed up again, instantaneously, during half an hour. Soon after this, the Aurora| faded out, and at 12 was wholly invisible, ex- cept as a bank of diffuse light in the north. , Feb. 22. A few streamers in the evening. « 623. At 10°, a few faint patches of light scattered over the heavens. 1839. *4 Jan. 11. Beautiful Aurora at 10°. * 5 Sept. 3. A magnificent display of Aurora. At the end of twilight, several columns of brilliant scarlet light had started from the northern horizon, and at 8" had nearly reached the zenith, streamers also ascending now from the east and south. In half an hour the whole firmament was flooded with light. Soon.after | 9, a corona was formed, in the direction of! the resultant of the earth’s magnetism at this | place. The columns then broke, and attempted to form again with partial success. At 10", the heavens were covered with a brush of light. Dorchester, 1839. 6 Sept. 1. Aurora Borealis, altitude 4°, steady, | © bo all apex E. of N. 5°, 72 45". Arch lower at 9® 7 Sept. 3. Aurora, ' 8 “ 28. Faint N. Aurora, altitude about 2°, with wane and dark below; at 9" 30™, strong steady light, altitude 15° to 20°, wane. 9 Oct. 22. Aurora during night. 10 Dee. 21. 7° 0™. Aurora, dark wane clouds be- low, white, steady, low, say 5°. Strong Au- rora, dark below, apex about 7° east of north. Aurora active at 8" 35™. Aurora low and steady. Arch well defined, steady. A few dark wane clouds above the arch. Aurora faint and low. Strong light among wane clouds. Wane, bright auroral arch quiet, wane rising at N. Cambridge, 1840. 11 Feb. 6. Auroraat altitude of 2°, diffused white light, steady, with long, low, dark wane clouds. 12 “ %, Low, faint Aurora, altitude 3°, with long, dark, pointed wane. 13 Mar. 22. Aurora Borealis, white diffused light, apex at 4°, with wane across. ; 14 “ 29, Aurora, dark wane below. *15 Apr, 24. Slight Aurora. 16 May 1. Aurora, height of arch 3° at N. Broken and active, with dark wane and de- tached nebula. “ 28. Remarkable Aurora. An arch was formed at 9°15™ P. M., running, as nearly as could be ascertained, at right angles to the magnetic meridian. A crown began to form at 11". Its position was referred to a Corone Rorealis, which was then upon the meridian. * Those marked with an asterisk were observed by myself: the others by the late W. C. Bond or G. P. Bond of the Harvard Observatory, being copied from its records by permission of the Director, Joseph Winlock. VOle X. 2 AURORAS OBSERVED AT CAMBRIDGE As it was at about the same altitude as the star, viz., 74° 52’, and to the east of the merid- ian, it could not have been far from the mag- netic pole of Dip. Shortly afterwards, the arch was broken up and the northern sky covered with pulsations of light. *18 May 29. Brilliant Aurora. The auroral arch was first seen at 9" §™ P. M., extending from a point nearly east to within a few degrees of the western horizon. The light was intense. The apex of the arch was situated, at first 20°, and at 9° 18" about 30°, south of the zenith. After this time the light broke and scattered, flying from east to west. This arch was en- tirely detached from the main body of the Aurora, and resembled a streamer. In the north there was a diffused light, but very bright and swift flashes toward the zenith. At 10" 35™, a large meteor was seen in the north, 20° high, descending towards the northwest. 19 June 21. Faint Aurora at 12" 0". *20 & 26. About 9212" P.M., an Aurora was seen in the north, of a white diffused light. At,1£> 56™, the Aurora assumed a dull appear- ance, with dark wane intermixed. At 1" 86™, the Aurora became more active, and some streamers were seen. The magnetometer was slightly affected at this time. *21 July 4. Between 12" 4™ and 12" 10", bright diffused Northern Lights : occasionally, long streamers: wane clouds near the Northern horizon: magnetometer quiet. *22 July 29. At S*® 21™, an auroral arch was formed, about 7° above the horizon, and very motionless. At 9" 40™, it began to move toward the zenith, and rose to the altitude of 30°. At 10% 30™, the Aurora bad disappeared. The light was dull during the whole time. *23 Aug. 19. A steady auroral arch was observed. It was double, and the altitude of its apex at 10° 30™ was 7° or 8°. Its color was dull white. This Aurora continued till 10? 36™, and at 10 47™ the Northern Lights had disappeared. *24 “ 28, An auroral arch appeared, running from east to west, of intense brightness and diffused, but without streamers. Its apex was nearly on the meridian, and at 9" 6™ its alti- | tude was about 45°. At 9" 56™, streamers shot up, 60° from the horizon: the altitude of its highest part was about 76° 49/, as found from | its place among the stars. on B . I | oi Aug. 31. Aurora, bright arch 4°, at 13°. 26 . Sept. 21. Strong Aurora with streamers, at 12". *27 Oct. 22. Between 8" and 9%, an Aurora ofa #28 steady blue light was first perceived : it af- terwards grew whiter and brighter. The alti- tude was 3°, with wane clouds below. At 11" 56", the Aurora was low. Noy. 30. At 10", an Aurora was seen of white diffused light. No regular arch was formed. The magnetometer was quiet. 1841. Jan. 14. Aurora, low wane, at 10" P. M. “ 27. Aurora, low and faint, at 9° 307. Feb. 22 Aurora, masses of white light, chiefly E. of N., at 8" 20% extending from eastern hor- izon to, zenith and passing to the south. « 23. Aurora low at N. by E. Streamer. Mar, 12. Auroral arch, altitude of apex about 5°, direction north by 10° east, steady, at 8" P. M. “ 14. Strong Aurora, wane below, masses of white light, detached above, at 7". “ 15. Dull Aurora with wane. “ 16. Pale Aurora, low, clear. “ 20. Slight Aurora, with wane at north. “ 21. Faint Aurora, with dark wane clouds. April 11. Aurora low, with wane. “ 14. Strong Aurora, with wane intermixed. “ 16. Aurora low, at 2° P. M, “ 18. Brilliant Aurora, streamers, 5° to 6°. “ 19. Aurora, decided arch with faint streamers, at 9 0™. May 8. Aurora, slight. P. M. July 141. Aurora, faint and low at 9° P. M. “ 19. Bright Aurora blended with wane, broken double arch, at 95 30™ P. M. Sept. 3. Midnight auroral arch, height about 5°, steady. “ 25. Masses of auroral clouds, at 8" an arch and streamers in N. N. W. , ‘© 26. Red auroral cloud at N. W. Oct. 14. Aurora at 10" P. M., low, ill-defined, with wane. 15. Slight Aurora, at 11> 30. 19. Aurora. ‘ 21. Aurora, diffused light, steady, and wane clouds low in North, at 9" P. M. Nov. 18. At 8° 20™, a very beautiful Aurora was seen. The period of greatest bright- ness was 851™ At 8* 26™, the Aurora had neatly vanished, leaving only faint traces of columns. At 92 6, there was observed in the north a large bright arch of light, mov- . 55 *56 *66 *70 AURORAS OBSERVED AT” CAMBRIDGE. 3 ing slowly westward, and also small drifting spots of bright light near the horizon. At 92 16™, the illumination extended from the northern horizon up to 30° of altitude. At 1i® 36™, the Aurora was shining brightly. Dec. 21. Faint*traces of Aurora, at 115 30™. “« 94. At 6> 36™, delicate shoots of Aurora were visible nearly up to the zenith. At 6" 46™, the Aurora disappeared near Capella, At 62 48", it disappeared from the zenith, and shone again in Auriga. At 6" 52™, no trace of the Aurora could be seen. The magnetometers were dis- turbed. but grew brighter in the zenith. 1842. Jan. 4. Between 6" 21™ and 6" 51™,an Aurora was seen in the northeast and northwest. « —§. About 6° 36", an auroral arch was visible in the northeast, at the altitude of 8°; but it soon died away. “« 4. At 10° 20", an arch of Aurora, 12° high, was seen in the north, northwest. The same arch, with another resting upon it, at an altitude of 20°, was visible at 10" 10™: at 10® 40", the upper arch was partly broken: at 10” 45™, a similar appearance was presented in the southeast. In both these arches, stars were visible, though not elsewhere, as it was cloudy. « 9. At 9" 21™, a light appeared, shining through the clouds in the north. “ 11,. Aurora Borealis at midnight, height 5° to 7°, bright, with wane clouds. “ 412. Faint Aurora Borealis, with cirri and wane, at 6" 30™. “ 15. Aurora Borealis, strong, well defined | arch at 9%. At 12", diffused light, low, at north, Jan. 15. A diffused arch was visible in the northwest, whose apex was from 10° to 12° high. At 9>26™, the arch was bright. Feb. 11, Aurora low (3°), diffused, brighter on the easterly part, at 7" P. M. Feb. 11. A slight Aurora was observed. Mar. 23. Aurora. P.M. Apr.10. Aurora, bright and steady, height about 3°, at 9" & 42. Auroral arch, bright, steady, altitude of apex from 7° to 10°. Aug. 8. At 2" 36™, an auroral light was seen in the north. Sept. 28. Aurora, low and diffused, with wane at north. Noy. 21. Bright Aurora. 93 100 101 102 Noy. 28. Aurora low in north, at 11" P. M. Dec. 27. Aurora among broken clouds, at 10" 1m Es ve 1843, Aug. 8. Strong and lively Aurora, with merry dancers, at 10" P. M. Sept. 27. Bright auroral arch, apex 5° N. by E. Oct. 14. Strong auroral arch 5°, apex north, at 6 30". More diffused at 7% Noy. 15. Slight Aurora at 5" A, M. 1844, Mar. 25. Aurora. April 5. A well defined auroral arch at 9", a very rare phenomenon of late, altitude of apex 8° to 5°, bore north by 5° E, at 10”. “ 17. Aurora, low at north with wane. May 7. Northern Lights and merry dancers, at 10° P. M. : “ §. Aurora again, low, at 9n P. M. Oct. 20. Bright auroral arch, apex due north, altitude about 4°. Dec. 14. Aurora. 1845. Jan. 9. Brilliant Aurora. April13. Masses of northern light at 10°. « 30. Auroral light.through clouds. Sept. 24. Northern light. « 25, Aurora. Oct. 21. Strong auroral light. Dec. 3. Aurora. “« 5. Aurora, low and diffused. 1846. Jan. 28. Very strong Aurora, apex E. of N. 8°, altitude 10°, Feb. 26. Aurora dancing. Apr. 15. Northern Lights 10°, brightest in N. E., shooters. “ 16. Aurora. May 4. Aurora shooting, faint. July 14. Northern Lights. « Aug. 11. Bright Aurora, with streamers, 8"-9". 24, Splendid Aurora. Sept. 10. Auroral light formed at 8 P. M. an arch of 10° in breadth, to the N. E. The interior of the arch was darker, or a deeper blue, than the rest of the sky, the lower edge of _ the arch cut « Urse Majoris on the west, and a Persei to the eastward. At 8> 20™, it was quite bright at times, masses of cloudy light. It faded rather suddenly, and the peculiar wane clouds, which usually accompany the Aurora Borealis, appeared scattered over the north, at about 5° to 10° above the horizon. 103 Sept.11. Aurora. 104 “ 22. Aurora from 8» to 9" in the evening. 105 “ 23. Aurora, low. 106 Oct. 7. Very brilliant and active Aurora. The night of the 7-8 was remarkable for its beauty and the fine display of Northern Lights. The formation of cloud in immediate connec- tion with the Aurora was watched with great interest. The apparent process was this. From the strong light of the arch, whose apex was high, and the inner part deep red, the streamers shot upward, and then formed in succession. WVapory light very faint, stronger light in mass. From this, or in the same direc- tion, was gradually formed cirrus and cumulus, from which the moonlight was strongly re- flected, and of steady outline. The usual dark wane clouds were formed below. 107. “ 19. Aurora with wane. 108 “ 21. Aurora at 10° P. M. 109 Dec. 9. Bright auroral arch 10°. in the N. W. Streamers 1847. 110 Feb. 6. Auroral light with wane clouds. 111 Mar. 8. Northern Lights at 9" P. M. 112 “ 19. At evening auroral arch 10°, apex 3° east of north, increased to one of the most lively and brilliant displays on record. 113 Apr. 17. Northern Lights strong, between dark cumulus. 114 “ 16. Aurora at 95, P. M., low. 115 May 15. Auroral arch, altitude 5°, at 9" P. M. 116 Aug. 3. Aurora 5°, 11" to 12", broken by 1°. 117 “ 21. About midnight a splendid Aurora, colored deeply with red. 118 Sept. 29. A splendid auroral display at 8 to 9" P. M. Some masses looking like the spec- trum of a prism, others of a brilliant red or rose color. One remained stationary for an hour in the S. E., at an altitude of 30°. 1848. 119 Jan. 28. Strong Aurora, with deep red light, but interrupted by clouds, at 8" 30™ P. M. 120 Feb. 24. Auroral light, strong. Several bril- lant displays of Northern Lights this month. 121 Mar. 8. Aurora low and diffused, at 9" P. M. 122 “ 22. Aurora. 123 “ 24, Aurora. | 132 At 9%, a fine, steady, well- | AURORAS OBSERVED AT CAMBRIDGE. defined arch. At 10" 30", merry dancers, bril- liant, casting strong shadows. 124 Mar. 25. Slight Aurora, low’ and diffused. 125 Apr. 5. Brilliant, active Aurora, at 11" 4. 126 “ 6. Aurora at 9° P.M. Extensive and diffused at 10" 30™,—* 127. “ 15. Aurora, brilliant arch and streamers at 9° P. M. 128 May 25. Aurora. A beam shot from a cloud near the horizon to Polaris ; exactly in direc- tion, a little short in distance. 129 “ 31. Aurora. 130 July 11. Splendid Aurora up to zenith ex- tending to the south and east. At 10", fine. Oct. 6. At 9° P.M., a very curious and re- markable ridge of light resembling a comet’s tail, or a light thin cloud, seen in the N., extending from the horizon up to the zenih, moving slowly off to the southward, at the rate of about a degree a minute, retain- ing its curved appearance as when first no- ticed. Supposed it to be auroral light. «« 25. Bright Aurora diffused with wane. Nov.17. Bright Aurora shining through the clouds, like moonlight. 151 133 134 ‘ 21. Aurora. | 135° <* 22, Aurora. : 136 Dec. 23. Northern light, diffused, altitude 10°. 1849. ‘ Feb. 19. Aurora from 105 to 12%. At mid- night, quite bright arch, apex 15°, broken at N. W., colored red. 137 138 Mar.17. Strong Aurora. 139 May 12. Aurora from 9" to 10" P. M., altitude 7°, broken arch. 140 July 13. Aurora from 9" to 10% P. M., slight auroral arch. 1850. 141 Mar. 4. Strong Aurora, also the same on the two preceding nights. 142 11 ~‘Aurora,at/9"P> M. 143 “ 31. Bright»Aurora with clouds floating in the north. 144 April 2. Slight Aurora during night. 145 <‘ 6. Aurora at 9° P. M., a fine arch with streamers, and very bright patches and cirro- stratus clouds below and among. 146 ‘“ %. Aurora with streamers and clouds. 147 May 3. Fine auroral arch at 9° P. M. 148 “ 1%. Fine Aurora from 14° to 15>. AURORAS OBSERVED AT CAMBRIDGE. 149 July11. Bright and active Aurora at 9" and 105 P. M., shooting to the zenith. 150 “ 12. Aurora midst clouds, streamers. 151 Aug.10. Aurora, about 3° high. At 11 15", curious appearance of the clouds, stretching from east to west exactly. Aurora bright. 152 “29-30. Faint Aurora from 9" to 10" P. M. 153 Dec. 27. Aurora. 1851. 154 Feb. 5. Bright Aurora. 155 “ 18. Bright Aurora. 156 Mar.29. Aurora. 157 May 24. Aurora, low’and diffused. 158 June 5. Strong Northern Lights with stream- ers, at 9 P. M. ; 159 . “* 27. Slight Aurora. 160 July 26. Strong, irregular Aurora, very bright, from 9* to 104. 161 Aug. 29. Aurora, low arch, full North, 9° P.M. 162 Sept. 4. A brilliant Auroragwith streamers, and drifting light, at 2" A.M. At 2" 30™, an , arch was formed to the southward, apex E. of S., about 40° high; the flashes on this side resembled what is called ‘‘ heat lightning.” To the N. N. W., and N. E. there was fre- quently rosy and green light. I have not seen a more brilliant display ; the wind was unsteady from the N. 163‘ 6. Auroral arch at evening until 115 apex N. to N. N.E., bright moonlight. 164 Sept. 7. At7>15™ P. M. Strong auroral arch 7°, streamers, and rose-light flashing, &c. until 7° 21™, then subsided with occasional streamers and diffused light. At4™ A. M. “i the 7th, Mr. Andrew Wyeth reports a bril-| liant Aurora covering the heavens, never! saw the like before. 165 Oct. 2. 166 A fine auroral arch at 9" P. M., apex | N. by E., about 12° high, clear bright moon- light, the arch steady, with*long cirro-stratus clouds below. « 20, Fine Aurora commenced at 7" P. M., | during twilight, with a well defined arch, its apex a few degrees E. of N., and altitude | about 15°. At 7", broken rolling billows, va- | rying every minute, streamer of white light, | very dark below ; at 8° 57™, a dark cloud be- | low fringed above with white light, and above it a regular arch, no streamer; at 9°10™ 305, a long narrow streamer at E. N. E. just bisected by Aldebaran; at 9°12” 55, it had moved about 5 one degree northwardly; this was a singular streamer and well adapted to show parallax, if observed elsewhere N. or S; at 9" 18™ short streamers from N. E. to N. W., rising from dark cloud below ; at 9" 20™ 355, a double arch, below steady, the one above has, streamers ; at 12}, diffused light, dark below apex of arch in the north. 167 Oct. 23. At evening till midnight, bright Aurora. At 6" 30™ well defined, regular arch ; then very strong light, radiating, fine, like iron at white heat, not streamers, but strong short rays or spikes. 168 Noy. 15. Low auroral arch, 3° high, apex 1° or 2° E. of N. Arch continuous and well defined, at 9" P. M. 169 Dec. 29. A very bright auroral arch at 6%, 5° in width, stretched across the north from N. E. to N. W., highest point about 30°. A smaller one, within this, having an alti- tude at highest point of about 15°, was seen. The space between these appeared quite dark, and also that within the small circle. *« 30. Aurora at 42 A. M. confined low in the north horizon, diffused sheets of light are continually rushing to the zenith, van- ishing before they reach the altitude of 25°. 1852. 171 Jan. 19. Bright Aurora at night. 172 Feb. 18. Bright Aurora. 173 “ 19. Aurora of extraordinary brilliancy commenced at evening twilight. Between 10" and 11", corona was in Dec. of Mars, and as nearly as possible in the meridian. 174 “ 20. The Aurora yet visible at 6, and pretty surely seen after sunrise at 6° 58™. 175 ‘ 26. Evening. Aurora. 176 April 10. Aurora below the clouds, at 95 10™. 177 May 18. Fine steady auroral arch during the evening till midnight. : 178 “ 19. Bright and strong Aurora, with considerable activity. 170 179 ‘* 20. Aurora bright, with streamers. 180 ‘ 21. Aurora low and diffused at 10%. 181 June 15-16. Aurora, arch, and streamers. 182 July 5. Aurora, from 9" to 10™ P. M.., inter- rupted by cirro-stratus clouds, some stream- ers, to the N. E. red light. 183“ 6. Slight Aurora, brighter at 10°. 184 ‘* %, Auroral arch. iy ee. 8. Aurora, low and faint. 186 ‘ 9. Bright Aurora over thunder clouds. 6 from 9" to 10%. with streamers. flashing of auroral light though the clouds. 187 July 10. NSS SEE BUCH) AS sabe LOD Feels 191 Aug. 14. 192 Sept. 2. OS tere a:, 194 Sept. 5. ulsysy, | WU a 196 ‘ 12. LOT, ae: 198) §oawite 199 US: 2007 Fee! 201 Oct. 5. 202 “ 9. 743) | 5 alah the clouds. 204 Nov. 10. confined to an altitude of 10°. | through the openings of clouds, in evening. | 205 © 11. 206 “ 12. 207 “ 15. 208 “ 16. 209 Jan. 9. 210 « 211 Feb. 1. 212 “ 14. 213 Mar. 8. 214. “« B39) 215 “ 18. 216 April 5. along the northern horizon. with wane cloud. Aurora, from 9" to 10% P. M. 2 #69. 218 May 2. Pale gs 220 * 5. 221 June 1. D2 SENG: 223) Son “9. PE BG aN 225 July 12. streamers, at 10" P. M. 226 Sept. 1. Ppa UC 30. Aurora bright and broken, at 10" P.M. 2. AURORAS OBSERVED AT CAMBRIDGE. Brilliant Aurora. Diffused Aurora. Auroral arch 5°, well defined. Aurora faint. Aurora, 3° to 5° high. Auroral arch, 6°. Aurora with streamers. ' Aurora, with merry dancers. Auroral arch, 3°. Bright Aurora between . clouds, Auroral arch. Aurora low and diffused, at 10" P.M. Bright auroral arch, 3°, streamers. Fine Aurora from 7° to 95 P. M., Aurora, P. M. Between 7" and 8, R. F. B. saw the Indications of auroral light through An Aurora, low, with streamers, | Strong Aurora with streamers seen Aurora. Aurora, at 9" P. M. | Aurora, at 95 P. M. 1853. Faint Aurora at 10" P. M. Aurora low and bright, at 9" P. M. Brilliant Aurora, P. M. Aurora, at 105 30™ P. M. Faint Aurora. Aurora in the evening. Bright Aurora with wane cloud, Slight Aurora, P. M. Bright and active Aurora, P. M. Dull Aurora. Dull Aurora. Aurora at 10" P. M., fine arch. Slight Aurora from 9" to 10" P. M., Auroral arch, diffused, 10" P. M. Active Aurora, broken arch and At evening, an Aurora. Soon after sunset, a bright Aurora| 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 | 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 was visible, with streamers reaching nearly to the zenith, brightest from 8" to 11”. Sept. 8. Aurora through clouds. ‘© 4, Slight Aurora, P. M. Oct. 31. Aurora low and diffused, P. M. Nov. 2. Aurora low but pretty, P. M. Dec. 24. First Aurora this month. 1854, Jan. 2. At evening, a double arch, Aurora remarkably well defined. Qi DEY. Bright auroral arch, altitude 7°. «« 28. Bright Aurora, at evening. Feb. 4. Strong and active Aurora, at 9-10". «16. Bright Aurora, broken, at 9° P. M. ‘© 27. Strong Aurora, with bright flashes. Mar. 16. Long bright beams of Aurora. ‘« 21. Aurorain evening, low and diffused. «« 28. Aurora, long beams of light. «29. Aurora in masses, at 9" P. M. April 20. Faint Aurora, at 9° P. M. ¢ ¥1. Strong Aurora, bright beams at 9". «23. Bright Aurora, at 9" P. M. May 1. Aurora at evening. «15. Aurora seen through broken clouds. “« 16. Aurora in streamers, at 9° P. M. “19, Aurora low and faint, 9"-10" P. M. June 12." Active and bright Aurora, very changeable, undulating to the westward, appearing to shoot this side of some cirro- stratus clouds, at 95-105 P. M. 13. Aurora, fine evening. July 10. Aurora. Sept-13. Aurora in the evening, streamers and wane cloud. “« 21. Aurora in the evening. ‘« 26. Bright auroral double arch, stream- ers below, at 8° 50™. « 24%. Streamers low, at 98 15™ P.M. Oct. 18. Bright Aurora from 9" to 11" P. M. Nov. 20. Aurora at 10° P. M. * 1855. Jan. 10. Aurora, at 9 P. M., low. Feb. 5. Diffused Aurora, at 9" P. M. mie 6. A bright well defined auroral arch, altitude of apex 6°, at 10" 30™. «12. Aurora amid cirro-stratus, at 9°. Mar. 12. Very bright Aurora, extremely ac- tive, double arch, dark below, colored light, most brilliant from 7 to 8 o’clock. By 10 o’clock it had subsided to a few streamers and diffused light, with something resem_ bling cirro-stratus clouds low at the north. AURORAS OBSERVED AT CAMBRIDGE. ‘264 Apr. 7. Aurora. 265 “ 9, Aurora in the evening. 266 “ 12. Fine auroral arch, apex 5°, broke into streamers at 10" P. M., dark below, clear. 267 “ 14. Auroral stréamers, faint, without arch, at 9° P. M. 268 Sept. 10. Bright Aurora, between wane clouds, near the horizon, 269 “ 17. Slight Aurora. 270 Oct. 9. Aurora, 271 Nov. 29. Aurora, from 6" to 84 P. M. 1856. 272 Mar. 30. Low diffused Aurora, at 9" P. M. 273 Apr. 22. A bright Aurora at 9" P, M., double arch at 9" 2", P. M., the exterior of the up- per limb just touched « Cephei and « Lyrae. 274 Aug. 22. Bright Aurora, 3° high, some stream- ers, ab 9" P. M. 275 “ 931. A rare exhibition of auroral light at 10° P. M. First, a regular arch of light, faint and the apex 20° high. Below this arch, broken masses of light, in form resembling cix- ro-stratus clouds, without streamers, the light steady, or changing its form slowly. One would suppose them to be cirro-stratus clouds, but that the stars Capella ete. shone with undiminished splendor though them. 276 Oct. 4. Bright Northern Lights, streamers, broken arch 5°, 277 Nov. 20. Aurora low at 11° P. M., none at 7°, 8) and 9*, 1857. 278 Feb. 26. At evening, Aurora for the first time, height of apex 4°, arched. 279 Sept. 7. Aurora in the evening, low arch 3°. 280 “ . 8. Aurora low, at evening. 281 “ 10. Bright Aurora, streamers rising from a bank of cirro-stratus clouds. 282 ,Nov. 9. Aurora, low and diffused. 283 “ 17. Aurora. 284 Dec. 18. Patches of Aurora forming and dis- solving rapidly. 285 “ 20. Bright Aurora in the evening. 1858. Bright Aurora, active. Some traces of Aurora at evening. Aurora very bright and active, gh, Aurora at evening, irregular arch, | 286. Jan. 8. 4s fe Ma IO 288 Feb. 16. 289 Mar. 13. dark below. 7 290 April10. Active Aurora, apex 10°, dark in- tervening clouds, at 9° P.M. 291 ‘* 11. Aurora at night. 292 ‘' 14, Diffused Aurora, at 9" P. M. 293 ‘ 15, Hvening, Aurora diffused, 294 May %. Strong Aurora between the clouds, at 92 P. M. 295 July 1. Aurora at 9"P. M., radiating. 296 ‘ 65. Aurora low. 297 Aug.30. Aurora bright, in the evening. 298 39“ 31. A bright Aurora, a strong beam of light from 9" to 10", N. N. EL 299 Sept. 1. Low auroral arch, about 5°, no streamers. 300 ‘' 7. Bright auroral arch, apex having altitude of 10°, somewhat diffused, with short streamers, dark cirro-stratus clouds below. 301 ‘* 8. Low diffused auroral light. 302 ‘ 9. A faint trace of Aurora, at 9° P. M, 303 ‘12. Bright but low auroral arch. 304 ‘14, Auroral arch, low. 305 Oct. 2. Aurora, low and bright. 306 ‘ 4, At evening, Aurora, in clouds. 307. ‘* §8. Auroral arch, faded before 10" P. M., altitude about 15°, well defined. 308 “ 9. Aurora, evening, cir. stratus below. 3809 ‘10. Auroralow and diffused, with clouds. 310 ‘27. Brilliant Aurora, noble arch. No co- rona, streamers of deep red, at 8" P. M. 311 ‘31. Aurora, diffused, bright all evening., 312 Noy. 1. Traces of Aurora at evening. 313 “ 10. Slight Aurora. 314 Dec. 1. Faint Aurora at evening. 315 “ 24. Auroral streamers, at 8 P. M. 1859, 816 Feb. 22. Fine Aurora, deeply rose tinted, soon disappeared and the sky clouded over. 317 ‘* 23. Slight Aurora. 318 Apr.29. Bright Aurora, the arches being perfectly formed, streamers and flashes of licht beyond the zenith. Lasted till late. 319 July 28. Bright Aurora in the evening. 320 Aug. 28. Fine Aurora, perfect arch at the south, with rose-colored streamers at the east 321 “ 29. The telegraph worked by the Aurora this evening, on the line between Boston and Portland, for two hours, with a power equal to 75 or 100 of Grove’s cups. 322 Sept.2. Aurora of an exquisite rose color at 3" A. M., in the east and south. At 9" P. M Aurora very active. fine double arch at the north. 323 Sept. 24. Aurora, at 9" P. M. 324 © 27. Slight Aurora. 325“ 28. Aurora, very fine from 9" to 11”. Aurora dimly visible through the, 326 Oct. 1. clouds, at 9° P. M. from 6" to 7° P. M. 328 ©“ 18. Aurora, at 9° P. M. From 10* to 11" P. M., | *351 June 7. 352 Sept. 20. AG ea AURORAS OBSERVED AT CAMBBIDGE. 1864. Aurora. Aurora visible in early twilight band about 7° wide extended from W.N. W. across. the zenith to B.S. E. At 7 20™, two arches, the highest 15° above N. ; horizon, connected by streamers. 327 “ 12. Remarkable auroral arch in south |*353 Noy, 19, 329 ** 20. Active Aurora, early in the evening. | *354 Jan. 8. 330 * 21. Aurora, at 9" P. M. 1*355 331 Dec. 14. Fine Aurora seen yesterday morn-|*856 “ 27. ing between 5 and 6 o’clock. 1860. 332) Jan. fd. 333 Mar. 27. 384 Apr. 13. ter in the evening. Sone ay Arora: at O°b. Ms 336 May 11. 337 “ 23. Slight Aurora, at 9® P. M. 338 July 19. Active Aurora, at 9" P. M. 339 Sept. 6. Aurora. 340 Oct.11. Active Aurora, at 8° P. M. 341 Nov. 4. Brilliant auroral arch, at 98 P. M. 342 Dec.15. Fine rosy Aurora, from 8 to 9°. 1861. ‘ 343 Jan. 13. Slight Aurora. "344 +‘ 22. Aurora, at 98 P.M. Red. 345 ‘“ 9381. Aurora, at 9° P. M. 346 Feb. 27. Aurora, at 85 P. M. 347 Mar. 9. Aurora, at 95 P. M. 348 Apr. 8. Aurora, at 9" P. M. 349 Aug. 4. Aurora. 1863. 350 Apr. 9. Fine auroral display. At precisely | 9° P. M., a remarkable: and very bright|*379 March 19. band from near the horizon, on either side,|*380 “ 24. passed exactly through our zenith and|*381 April 13. It moved slowly to "382 “ 17. thesouth. Observed at Newburyport at the J. H.S. saw the same, or nearly within 4° of Arcturus. same time. the same band, reform about 12" 20”. Fine rosy Aurora, from 8* to 9%. Very brilliant Aurora, of a rich red. +361 Aurora at 9° P. M.; very active la-| Aurora last night, in the horizon. *35T Feb. 16. | *358 Mar: “5: |*359 AG: | *360 F362) ecole |*363 May 3. 364 “ 14. *365 June 15. (*366 July 12. *367T Sept. 6. (#368) 0 (12. |*369 Oct. 3. *370 4, | *371 May 2. | “372. #373 ON. |*374 July 28. *375 Sept. 21. #376 «23. FSU la 20: sety (tee CR Plit yates way evening. *384 May 12. Aurora. 1866. Slight Aurora, at 9°. Aurora, from 6" to 10°. Slight Aurora. Low arch, at 9". Aurora, at 105. Aurora from 9* to 12", brilliant in N- Arch from east to west, at 11". Slight Aurora in north. Slight Aurora in north. Aurora, at 10° 30™. Aurora, at 10%. Aurora low in the north, at 11" 30”. Aurora from 11* to 12%. Slight Aurora, at 10". Aurora, at 10. Aurora, feeble and low. Aurora, feeble and low. 1867. Slight Aurora. Slight Aurora. Aurora. Bright at 10°. Aurora. Bright Aurora. Aurora. Slight Aurora. Aurora. 1868. Slight Aurora, at 10°, Slight Aurora, at 10". Bright Aurora, at 11°. ’ Slight Aurora, at 10" 30™. Aurora in the north during the Arch low. About 10*, streamers. Aurora at 11". TT On the Periodicity of the Aurora Borealis. BY JOSEPH LOVERING, HOLLIS PROFESSOR OF MATHEMATICS AND NATURAL PHILOSOPHY IN HARVARD COLLEGE. Communicated, December 6, 1864. Tue object of this memoir is to present a catalogue of auroras from the earliest observed down to the present epoch, and upon this catalogue, as a foundation, to recon- struct the laws of periodicity of the phenomenon. For the observations prior to 1750, Tam indebted, principally, to Mairan’s first and second catalogues; the latter itself being compiled, for the most part, from numerous smaller catalogues existing in his day. I have introduced, however, many additional observations in high latitudes, ruled out by Mairan, in accordance with the plan of his work; as well as some old auroras brought to light by the investigations of Quetelet, Boguslawski, and Chasles, or by my own researches. For the last century I have used the following materials: 390 auroras observed at Cambridge, Mass., between 1742 and 1793 by Winthrop or Wigglesworth ; 316 auroras observed at the same place, between 1840 and 1864, by W. C. Bond or G. P. Bond or myself; 36 auroras observed at Boston, Mass., between 1818 and 1840, by Hale; 198 auroras observed at Salem, Mass., between 1786 and 1820, by Holyoke :—all published first by myself. I have also compiled, from their original places of publication, 212 auroras observed at Worcester, Mass., between 1839 and 1862, by Woodward, Chandler, or Bemis; 160 auroras observed at Providence, R. I, between 1832 and 1860, by Cas- well; 74 auroras observed at Burlington, Vt. in 1852 and 1853, by Thompson; 89 1 Mairan’s first catalogue consists of 229 auroras. His second catalogue of 2137 observed auroras, of which 1441 are inde pendent of each other, comprises Frobes’s catalogue of 796 auroras observed between 583 and 1739. To these are added Delisle’s catalogue of 233 auroras observed at St. Petersburg between 1726 and 1736; Celsius’s catalogue of 384 auroras observed in Sweden between 1716 and 1732; Kirch’s catalogue of 106 auroras observed at Berlin between 1707 and 1735 ; Weidler’s catalogue of 91 auroras observed at Witiemberg between 1730 and 1751; the catalogue of Zanotti and Beccari which contains 88 aurorss, observed in Italy between 1727 and 1751; Short’s catalogue of 148 ancient auroras ; Kirch’s catalogue of 89 auroras observed between 1549 and 1657 ; and 202 auroras compiled by Mairan himself from the Transactions of the Royal Society of London. VOL. X. 2 10 ON THE PERIODICITY OF THE AURORA BOREALIS. auroras observed at St. Martin, Canada, in 1853 and 1854, by Smallwood ; 53 auroras ob- served at Wilmington, Del. between 1827 and 1833, by Gibbon ; 218 auroras observed at Newberry, Vt., between 1830 and 1862, by Johnson; 389 auroras observed at Toronto, Canada, 169 at Quebec, 107 at London, Canada, 151 at Newfoundland, between 1848 and 1851, by Lefroy, &c.;+ 84 auroras observed at Jena, Germany, between 1770 and 1796, by Zeissing ; 341 auroras observed at Stockholm, Sweden, between 1783 and 1792, by Nicander; 942 auroras observed at St. Petersburg, between 1736 and 1861, by va- rious Russian meteorologists ; 231 auroras observed at Brussels, Belgium, between 1778 and 1851, by Mann, Quetelet, &c.; 634 auroras observed at Upsal, Sweden, between 1732 and 1762, by Celsius, Ferner, or Bergman; 225 auroras observed at Berlin, Prussia, between 1735 and 1789, by Beguelin; 108 auroras observed in Paris, France, between 1784 and 1842, by Cassini or Bouvard; 175 auroras observed at_Montmorenci or Laon, France, between 1771 and 1805, by Cotte; 81 auroras observed at Spydberg, &e., Norway, between 1784 and 1787, by Wilse; 240 auroras observed at Sagan, Prussia, between 1781 and 1792, by Preuss; 288 auroras observed in Scandinavia, &e., between 1837 and 1840, by Lottin, Thomas, &c.; 216 auroras observed at Mannheim, Germany, between 1781 and 1792, by Hemmer; 48 auroras observed at Copenhagen, Den- mark, between 1782 and 1788, by Bugge; 54 auroras observed at Ratisbon, Germany, by Heinrich, and 47 auroras observed at Prague, Austria, by Strnad, between 1781 and 1791. With these I have united Loomis’s catalogue of 813 auroras observed at New Haven, Conn., between 1763 and 1854, by Stiles or Herrick ; Hough’s catalogue of 1205 auroras observed in the State of New York, between 1826 and 1851; Leche’s catalogue of 119 auroras observed at Abo, Finland, between 1749 and 1762;? Argelander’s catalogue of 163 auroras observed at Abo, between 1825 and 1831, and at Helsingfors, between 1832 and 1837; Hallstrém’s catalogue of 682 auroras observed at Abo, between 1748 and 1828, and at Helsingfors, between 1829 and 1843; Block’s catalogue of 430 auroras observed at Gothaab, Greenland, between 1841 and 1846; Noodt’s catalogue of 91 auroras observed at Hammerfest, Norway, between 1850 and 1861; Dalton’s catalogue of 250 auroras observed at Kendall or Keswick, England, between 1786 and 1793, and his catalogue of 185 auroras observed in Great Britain and Ireland, between 1794 and 1834; Huxham’s catalogue of 120 auroras observed at Plymouth, England, between 1728 and 1748; Broun’s catalogue of 184 auroras observed at Makerstoun, Scotland, between 1843 and 1849; Stevenson's catalogue of 238 auroras observed at Dunse, North Britain, between 1838 and 1847 ;° Hansteen’s 1 Phil. Mag., Fourth Series, IV. 61-63. 2 Svenska Vetensk. Acad. XXIV. 267. 3 Proc. Royal Society, London, VI. 291. Phil. Mag., Fourth Series, VI. 21. ON THE PERIODICITY OF THE AURORA BOREALIS. ii catalogue of 534 auroras observed at Christiania, Norway, between 1837 and 1853 ; Rudolph’s catalogue of 185 auroras observed at Jakobshavn, Greenland, between 1840 and 1851; Hisenlohr’s catalogue of 87 auroras observed at Carlsruhe, Germany, between 1779 and 1831; and Cotte’s catalogue of 231 auroras observed at Franeker, Holland, between 1771 and 1781, by Van Swinden. Much assistance has been found in Force’s notices of auroras published in the Smithsonian Contributions. No great use could be made of Boué’s learned catalogue on account of the confusion of o/d and new style, the substitution of the number of auroras in a month for the day of the month, and other numerous inaccuracies in the compilation and printing of this catalogue. It is not necessary to refer to the general catalogues or tables of Arago, Quetelet, Kiamtz,? Muncke, Bertholon, Reuss, or to the Collection Académique. as they contain little not derived from older sources already enumerated. I have also made a laborious examination of the publications of the English, Swedish, French, German, Russian, Austrian, and Italian Academies, and of the Journals of those countries,and have collected from these and other sources, as travels, Arctic voyages, histories, &c., numerous examples of auroras which have entered into no former catalocue. The name of the country where an aurora is observed, when known, is printed in #alics. The name of the observer is added if possible, and also that of the author of the printed record, with such other authorities and references as may be convenient for the student. An attempt has also been made to reduce the date of each observation, when given in o/d style, to the Gregorian reckoning. But this task is beset with great difficulties. In 1780 Van Swinden’ submitted to the Royal Academy of Sciences of Paris the prospectus of a “Plan d’un Traité sur PAurore Boréale, pour servir de suite & celui de M. de Mairan.” Van Swinden informs the public that it was within his power to insert many auroras which Mairan had overlooked, — partly drawn from printed books, but especially derived from two manuscript collections which had been given to him, — the first of 170 auroras observed at Breda by Eckhard, between 1719 and 1740, for which he was indebted to the son of the observer (of these auroras there are 64 which are not found in the catalogue of Mairan); and the second of 64 auroras observed in North Holland, between 1741 and 1749, which Van Swinden received from Engelman. Van Swinden also promised some observations on auroras made during a maritime voyage, in 1741, which he had in manuscript. He also proposed to extend Mairan’s catalogue from 1751 to 1778, by adding printed and manuscript 1 Sur la Physique du Globe, par Quetelet. 2 Lehrbuch der Meteorologie, III. 468. % Rozier, Observations sur la Physique, XV. 128-134. 12 ON THE PERIODICITY OF THE AURORA BOREALIS. observations, partly made by himself and partly obtained from his brother, at La Haye, and by Engelman, at Amsterdam. Van Swinden lived until 1823, and yet, to the grief of science, he does not appear to have carried his plan into successful execution. In regard to Mairan’s chronology Van Swinden offers the following criticism : — “Le troisitme objet qui nous occupera sera de rectifier les erreurs qu'il nous pardit que de Mairan a commis. Nous ne prétendons pas rabaisser par-la le mérite de ce savant illustre : il est bien plus aisé de rectifier quelques inad- vertances, que de débrouiller un chaos de plus de deux mille observations. Ces erreurs proviennent toutes d’une seule source: de la reduction de l’ancien style au nouveau. La table donnée par M. Frobés sert de base a celle de M. de Mairan. Or M. de Mairan a cru (p. 468) que M. Frobés s'est servi de I’ ancien style, tant avant qu’ aprés la reforma- tion du Calendrier: et en conséquence il a avancé toutes les dates, qui se trouvent dans la table du physicien allemand de onze jours pour ce siécle, et & proportion pour les sitcles précédens. Mais on peut prouver tant par toute la contex- ture de la table de M. Frobés que par ses propres paroles (page 35 de son ouvrage') qu’il a employé le nouveau style au moins la plupart du temps et pour les observations d’ Allemagne, pays dans les Etats Protestants tuquel on sait que le nouveau style est en usage depuis le commencement de ce siécle. Cette inadvertance de M. de wiairan I’a conduit a deux erreurs essentielles: la premitre, que les dates des aurores boréales, mentionnées par M. Frobés, et tirées de son ouvrage par M. de Mairan, se trouvent, pour ce siécle, trop avancées de onze jours. La seconde, qu’on trouve souvent un double emploi de la méme aurore boréale, si elle se trouve citée par M. Frobés et par quelqu’ av're auteur. Par ex- ample, l’'aurore boréale du 16 d’Octobre 1719, se trouve au 16 de ce mois, suivant l’observation de M. Kirch; et l'on en trouve une autre au 27 du méme mois, qui est celle que M. Frobés a rapportée au 16, et qui M. de Mairan a placée au 27 par le changement de style. Voila done une seule aurore boréale réellement employée deux fois. Nous nous trou- vons done obligés de refondre entitre’ment la Table chronologique et d’y mettre toute l’exactitude dont nous serons capables.” This is the passage in Mairan’s treatise to which Van Swinden refers : — « M. Frobés et la plupart des Auteurs ou il a puisé, ayant suivi l’'ancien style dans leur dates, tant avant qu’ aprés la reformation du calendrier, j’ai été obligé de ramener au nouveau ‘outes celles que M. Frobes n'y a pas ramenées: et cela non seulement pour la commodité du plus grand nombre des Lecteurs, mais surtout, parce que le nouveau style est conforme 4 l'état du Ciel, et que l’ancien ne l’est pas, et s’en écarte considérablement, depuis le 1V™e siécle.*” It appears from the sentence I have partly italicised that Van Swinden is mistaken when he says that Mairan has advanced ai/ the dates given by Frobes, as if they had been given by the latter in old style? In many cases Frobes has specified the style which he adopts, and it is sometimes according to the Julian and at other times accord- ing to the Gregorian calendar: and in these plain cases Mairan has committed no error. Moreover, in Maraldi’s observations, where the style is not specified, but where it must 1 Van Swinden probably alludes here to the following passage of Frobes, found not on page 35, but on page 95. “‘ Studio Suecicas et Germanicas luminis borei observationes ab invicem disjungimus: siquidem ipsarum tempora, propter styli seu calendarii diversita- tem, haud omnino congruunt. Facta autem styli utriusque comparatione, quoties phenomena Suecica cum reliquis coinciderint explorari hand difficulter poterit. Ceterum observari quoque hic meretur ea phenomena que Decembr. m. d. XXL. et seq. in Snecia contingunt, apud eos qui stylo novo seu calendario emendato utuntur ad annum proxime sequentem referri oportere. 2 Traité Physique et Historique de l’Aurore Boréale, p. 468. See, also, pp. 188, 189. 3 Nova et antiqua Luminis atque Aurore Borealis Spectacula, pp. 57, 58, 71-94, 95-98, and 100-118. . ON THE PERIODICITY OF THE AURORA BOREALIS. 13 have been known to Mairan, no change has been made, as in the auroras of April 11, 12, and 13, of Dec. 15 and 16, 1716; of April 6, 9, 10, and 11, 1717; of Feb. 6 and 10, of Nov. 29, 1720; of Feb. 17, 23, and 28, 1721.1. In other cases there is no doubt that Mairan has occasionally been led into error by advancing dates already expressed in the new style. No copy of Frobes’s book could be found in this country, and I did not succeed in obtaining a copy from Europe until the printing of my own catalogue had proceeded too far to allow me to introduce any changes. It is to be understood, there- fore, that the dates here attached to Frobes’s auroras are the same as those adopted by Mairan, unless it is specially stated to the contrary. Although the catalogue of auroras, which I now present to the public, comprises nearly 10,000 independent auroras, and more than 50,000 observations, I do not claim that it has exhausted the supply. On the contrary, I can myself point out some of its deficiencies. It is well known that Musschenbroek observed the aurora during 29 years at Utrecht and Leyden, and collected a catalogue of 720 auroras. In one of his works” he has arranged these auroras according to the months in which they ap- peared; but the individual observations, so far as I am aware, have never been pub- lished. A laborious meteorologist® of the last century has stated that he possessed in manuscript the observations of Musschenbroek, and that he intended to publish them with others in a third volume of Memoirs; which, however, never appeared. As Musschenbroek has classified his auroras according to the months of the year, they are available in the study of the annual changes of the aurora; it is to be regretted that they cannot also be used in the investigation of those fluctuations which observe longer periods. Of the different countries which have contributed to swell the grand capital of auroral observations, Russia, always devoted to meteorology and the physics of the globe, stands foremost ; an almost uninterrupted series of auroras having been regularly observed and published at St. Petersburg, since the foundation of the Imperial Academy of Sciences in 1726. Not finding the published record of auroras for St. Petersburg so complete in recent years as formerly, I wrote to M. Kupffer, Director of the Central Physical Observatory of Russia, requesting to be furnished with full materials. In reply to my inguiries I received from Kupffer a table, which contains, as he says, the auroras observed in Russia between the years 1841 and 1861 inclusive* Kupffer remarks that the aurora borealis always announces its presence by very strong oscillations of the magnetic needle, which 1 Frobes, Nova et Aniiqua Luminis atque Aurore Borealis Spectacula, pp. 79, 81, 89, and 90. 2 Cours de Physique, 2489. 3 Cotte’s Mémoires sur la Météorologie, I. 366 and II. 169. Also, Journ. de Phys. LXX. 168 and LX XIU. 153. * It is incorporated in my Yearly and Monthly Table for St. Petersburg, pp. 186, 187 of this Memoir. 14 ON THE PERIODICITY OF THE AURORA BOREALIS. it is impossible to confound with the irregular oscillations by which it is sometimes affected, and in the recurrence of which Sabine has discovered a striking periodicity. These strong and irregular disturbances are repeated over the whole line of Magnetic Observatories from St. Petersburg to Nertchinsk, so that a table, derived from the registers of St. Petersburg, is likewise adapted to the other observatories. In many localities the heavens may be shut in by clouds and the auroras not visible, when their presence is suspected from the oscillations of the needle. Ideler, in his “ Meteorologia Veterum Greecorum et Romanorum, p. 49, devotes a few pages to the investigation of “Aurore borealis apud veteres vestigia.” Ideler makes the following criticism upon the supposed allusions of Aristotle to the aurora: “ Aristoteles describit phenomena, que xaouara, Bodivove, kat aluaradn xpayaTa vocat. Quale intelligendum sit pheno- menon, re vera dictu est difficillimum. Itaque, priusquam de ipso agimus, quantum fieri potest accuratam descriptionem ex ipsius verbis eruere conemur. Phenomena non nisi nocte serena cerni, incensionem flamme ardori similem esse, com- parari posse splendorem cum flamma per fumum visa, dicit; denique non longo temporis spatio in ceelo remanere. Colo- res gigni refractione luminis in crassiore aére censet, exemplum afferens rubicundum stellarum orientium et occidentium colorem, potissimum vero eminere puniceum et purpureum, quia cwruleus cum atro confundatur et vix discerni queat. Multi de aliis rebus cogitaverunt, nos non dubitamus quin auroras boreales intellexerit Aristoteles (quarum fortasse nul- lam suis ipse oculis conspexit) imprimis verbis commoti: Omnino in tenebris albus color tot precbet varictates, ut flammam per fumum adspicere tibi videaris: qu ad borealis aurore speciem proxime accedunt. Difficultates tamen remanent plures; prior, cur Aristoteles non dixerit, ejus modi phenomena in boreali tantum plaga oriri, immo in libro de mundo (si omnino illius auctor est, qua in re video dissentire grammaticos) dicat id rarissime tantum versus meridiem et septemtriones oriri ; altera deinde in verbis: Interdiu Sol cohibet, noctu vero, excepto uno colore puniceo, reliqui propter eundem fere cali colo- rem non apparent, cum tamen boreales aurorz omnes prismaticos colores prebeant.” * Ideler quotes the following lines from Lucan’s Pharsalia, I. 526 : — “ Jenota obscure viderunt sidera noctes Ardentemque polum flammis, czloque volantes Obliquas per inane faces, crinenque tremendi Sideris, et terris mutantem regna cometen. He also adduces the following passage from Tacitus :? — “ Sonum insuper audiri, formas deorum et radios capitis adspici persuasio adjicit.” The lines quoted in the Annals of Philosophy, IX. 250, do not appear to me to refer to the aurora. Armorum sonitum toto Germania celo Audiit$ 1 See Aristotle’s Meteorol., Lib. I. Cap. 5. Also, Ideler’s Aristotelis Meteorologicorum Libri, I. 374 and II. 330. 2 Germania, Cap. XLV. 8 Virgil, Georgic. I. 474. ON THE PERIODICITY OF THE AURORA BOREALIS. 15 Milman? makes the following allusion to the aurora which appeared in the summer of 167 B. C.: — “ The doom of the city had not been without its portent. Early in the year the heavens had been ablaze with what appeared horsemen in cloth of gold, tilting at each other, with the flash of swords and bucklers. The wild tumult in the PP’ 8 'S sky lasted for forty nights.” Milman draws his description from this passage in Maccabees : — “ And then it happened that through all the city, for the space almost of forty days, there were seen horsemen running in the air, in cloth of gold, and armed with lances, like a band of soldiers.; And troops of horsemen in array, encounter- ing and running one against another, with shaking of shields, and multitude of pikes, and drawing of swords, and casting of darts, amu glittering of golden ornaments and harness of all sorts.” ? Milman adds, in a note: — © Jn my younger days I described an Aurora Borealis, I had myself seen it, in lines which might seem to be, but were not, taken from the book of Maccabees. “ Forth springs an arch, O’erspanning with its erystal pathway pure The starry sky: as though for Gods to march, With show of heavenly warfare daunting earth, To that wild revel of the northern clouds: They now with broad and bannery light distinct Stream in their restless waverings to and fro, .. . Anon like slender lances bright start up, And cross and clash, with hurtle and with flash Tilting their airy tournament. Samor, Book III. p. 42.” Milman also alludes to this passage in Humboldt’s Cosmos:? “Mit nicht geringer Wahrscheinlichkeit kann man yermuthen, dass das merkwiirdige von der Erde pyramidal aufstei- gende Licht, welches man auf der Hochebene von Mexico 1509, vierzig Nachte lang, am ostlichen Himmel beobachtete und dessen Erwihnung ich in einem alt-aztekischen Manuscripte der Kénigliche Pariser Bibliothek, im Codex Telleriano- Remensis, aufzefunden, das Thierkreislicht war.” In the book of Job,‘ an early allusion is supposed to have been made to the aurora borealis : “ And now men see not the bright light which is in the clouds: but the wind passeth and cleanseth them. Fair weather cometh out of the north: with God is terrible majesty.” i History of the Jews. Third Edition, I. p. 461. 2 Second of Maccabees. V. 2d and 3d verses. ® Kosmos, I. 145. See also Plutarch’s Lives, III. 124. Marius. * Job XXXVII. 21 and 22. 16 ON THE PERIODICITY OF THE AURORA BOREALIS, Dr. G. R. Noyes translates these verses thus : “ Men cannot look upon the light, When it is bright in the skies, When the wind hath passed over them and made them clear, And a golden brightness cometh from the sky, — But with God is terrible majesty.” On this passage Dr. Noyes has made these comments in a note: “And a golden brightness : literally gold ;—from the sky: northern lights, or aurora borealis, to be referred to. But it literally, from the North. Hence some have supposed the is more probable that the Northern, or upper hemisphere, stands for the whole firmament here, as in Chap. xxvi. 7. I suppose the reference is to the dazzling brightness reflected from the skies when the sun is in the meridian. ‘The light, mentioned without any special application, seems naturally to refer to the light of the sun. This light also dazzles the eye more than that of the aurora borealis.” GENERAL CATALOGUE OF AURORAS. 502, Obsequens,} Lycosthenes,? and Frobes.? 465. Livy, Obsequens, Frytschius,* Frobes. “ __ Lycosihenes, Chasles,° Boguslawski. 463. Livy, Obsequens, and Lycosthenes. « _ Frobes, Chasles, and Boguslawski. 461. Obsequens, Lycosthenes, Frobes,® and Chasles. 460. Lycosthenes, Chasles, Boguslawski.” 443. Athens. Nihusius,® Frobes. 394. Pliny,® Calvisius, Frobes. 350. Frytschius," Frobes, Chasles, Lycosthenes. 334. Hyypt. Lycosthenes, Frobes,” and Chasles. 237. Thuscia. Lycosthenes, Frobes, and Chasles. | 223. Thuscia. Obsequens and Lycosthenes. ce Frytschius, Frobes, Chasles, and Bogusl. 217. Rome, Sicily, Preneste. Obsequens. “ce Livy, Lycosthenes, and Frobes. 1 De Prodigiis, Cap. IX. 2 Prodigio1um ac Ostentorum Chronicon, p. 70. 3 Nova et antiqua Luminis atque Aurore Borealis Spectacula. + Catalogus Prodigiorum. 5 Compt. Rend., XII. 499. Nouy. Mém. del’Acad. Brux., XV. ® Boguslawski says they were in the years 463, 461, and 460. 7 Pogg. Ann. Bd. XC. Erginzungsband IV. p. 62. Livy, III. Boguslawski says it was in the year 458. ® De Divinatione Sacra et Profana, Lib. VII. Cap. VII. ® Historia Nat. Mundi, Lib. II. Cap. XX VII. Opus Chronologicum. Pliny, Historia Nat. Mundi, Lib. II. Cap. XX VII. 2 Vincentius, Speculum Naturale (7), Lib. V. Cap. LV. 15 He quotes Cassiodorus. Boguslawski gives the year 236. 1* Boguslawski gives the year 214. B. C. 208. Lycosthenes,’® Chasles, and Boguslawski. 204. Setia. Livy and Obsequens. Cs Lycosthenes, Peucer,!® and Frobes. 203. Anagnia. Livy, Obsequens, Peucer, Frobes. « —— Lycosthenes, Chasles, and Boguslawski. 202. Nihusius and Frobes. 200. Lueania. Obsequens and Lycosthenes.” Frobes, Chasles, and Boguslawski. 175. Gabii. Livy and Obsequens. Lycosthenes and Boguslawski. Lanuvium. Livy, Obsequens, and Frobes. Lycosthenes and Boguslawski. Anagnia. Obsequens and Lycosthenes. Peucer, Frobes, and Boguslawski. 168. Seneca, Lycosthenes, and Frobes.1® 167. Lavinium. Obsequens, Lycosthenes, and Frobes. 166. Lanuvium. Obsequens and Lycosthenes. Frobes and Boguslaw=ki. ? Capua. Formia. Obsequens. Lycosthenes, Frobes, and Boguslawski.” Anagnia. Obsequens and Lycosthenes. Frobes and Boguslawski. 136. Pre@neste. Obsequens, Lycosthenes, Peucer. 18 He quotes Diodorus Siculus, VII. 161. torice, Lib. XVI. 16 Commentarius de Precipuis Divinationum Generibus, p. 345. 17 Boguslawski gives the year 197. 18 Maccab. Bk. II., Ch. 5, verses 2 and 3. Journ., XLVIT. 148. 19 Bogvslawski gives the year 160. Bibliothece His- Edin. New Phil. \ ON THE PERIODICITY OF THE AURORA BOREALIS. ET 136. B. C. Nihusius, Frobes, and Boguslawski. 133. Nihusius and Frobes. 128. Obsequens, Lycosthenes, Frobes. 113. Obsequens, Lycosthenes, and Frobes.t 103. Ameria. Obsequens and Lycosthenes. “ — Tudertum. Frobes and Boguslawski? 94.? Vesta. Obsequens and Lycosthenes. “ — Frobes and Boguslawski. 93. Vulsinwm. - Lycosthenes. “ — Frobes and Boguslawski. 92. Obsequens and Lycosthenes. “ Frobes and Boguslawski. 63. Obsequens, Lycosthenes, Frobes, Boguslawski. 17.? Obsequens, Lycosthenes, and Frobes. 14. A.D. Seneca,® Frobes. “ — Lycosthenes, Wolffius.* 20.? Seneca, Frobes.° 27.? Fincelius, Liebknecht,® and Frobes. 31.? Seneca,’ Frobes. 50. Lycosthenes, Frobes. 65. April 8. Jerusalem. Lycosthenes, Frobes.® 72. May 21. Chasles.? [ Doubtful. ] 162. Lycosthenes and Chasles. 196. Lycosthenes and Frobes. 384. Lycosthenes and Frobes. 894. Pilgram.” [Probably a comet. ] 397.? Pilgram. 400. Lycosthenes and Frytschius. “© Frobes and Chasles. 402. Frytschius and Frobes. 412.? Lycosthenes and Chasles. 450. Pilgram. 451. Pilgram. 454, Lycosthenes, Frytschius, and Frobes. “« — Pilgram, Chasles, and Boguslawski. 462.? Lycosthenes and Frobes. 1 Pliny, Historia Nat. Mundi. Lib, II. Cap. X XXIII. 2 Pliny, Historia Nat. Lib. II. Cap. LVIII. (B. says 102.) 8 Naturales Queestiones. Lib. I. Cap. 1. 4 Lection. Memorab. Cent. XIV. p. 14. 6 Tt is doubtful whether this was an aurora. 6 Pharus sive de Prodigiis Ignis Czelest. p. 11. 7 Sub Tiberio Ceesare cohortes in auxilinm Ostiensis coloniae cucurrerunt tanquam conflagrantis. Quest. Nat. I. 15. The same mistake was made at Copenhagen in 1731, and a hundred years later at Konigsberg. It was again repeated at New Orleans in 1839, and in London in 1847. (See note 5, p. 20, right col.) 8 He quotes Josephus, De Bello. Lib. VII. Cap. 12. ® Chasles quotes from Lycosthenes, but Boguslawski says he cannot find the passage. 10 Untersuchungen iiberd. Wahrscheinliche d. Wetterkunde &e. VOL. X. 3 480. 488. O01. O41. 552. 555.7 556.? 560. 563. 770. XXXII. p. 299. Pilgram. Berlin. Pilgram. Aug. 22. Edessa? Frobes, Mairan, Pilgram. Pilgram. Pilgram. Lycosthenes and Boguslawski. Lycosthenes and Boguslawski.? Berlin. Pilgram. Gregory,’ Quetelet,’ and Boguslawski. Frytschius, Tylkowsky,® and Frobes. Pilgram. Lycosthenes, Frobes, and Chasles. Italy. Frytschius, Lycosthenes. Frobes, Pilgram and Chasles. Pilgram. Paris. Gregory. Lycosthenes. Frobes, Pilgram and Perrey.® Pilgram and Perrey. Feb. 4. Frobes, Mairan,? Pilgram, Acad. Coll.” Gregory, Frobes and Bertholon.™ July. Gregory, Mairan, and Pilgram. Sept. 2. Gregory, Mairan, and Pilgram. “ a. Gregory, Mairan, and Pilgram. “ x. Gregory, Mairan, and Pilgram. Gregory ? Frytschius and Frobes. Rome. Tylkowsky, Liebknecht,” Frobes. Pilgram. ; Lycosthenes, Frobes, and Chasles. Pilgram. France. Frytschius and Frobes. Frytschius and Frobes. Rome. Frytschius, Lycosthenes, Frobes. Pilgram. Pilgram. Pilgram. Pilgram. 1 Traité Physique et Historique de 1’Aurore Boreale, p. 180, | Mairan places this aurora in the year 502. 2 Annals of Philosophy, IX. 250. Matthews, p. 101. 3 He quotes Sigebertus in Chronicon ab anno 381 ad 1113. 4 Gregorius Turonensis Historia Francorum. Lib. LV. Cap. 5 Mém. de l’Acad. Bruxelles, XV. 22. 6 Physica Curiosa, P. IIT. p. 246. 7 Frobes describes a strange light seen this year, but it was not probably an aurora. 8 Compt. Rend. XIV. p. 69. 9 Mairan quotes Gregoire de Tours. Hist. de France, Liy. VI. From the description it appears to have been a meteor. 10 Collection Academique, P. Etrang. VI. 507. M1 Encyclopedique Methodique — Physique I. 341. 12 Pharus sive de Prodigiis Ignis Ceelest, p. 32. ON THE PERIODICITY OF 778. Lycosthenes and Frobes. © Mairan, Pilgram, and Acad. Coll. 786. Dee. Quetelet,’ and Boguslawski. 800. Frytschius and Frobes. 803.? Lycosthenes, Frobes, and Chasles. 806. Ado, Frobes, and Pilgram. 807. Mar. 3. Bouquet, Pilgram, and Quetelet. 808. Feb. 2. Lycosthenes, Frobes, Mairan,? and a “ 2. Academical Collection. 808.? Aug. 14, Academical Collection. 827. Bouquet, Pilgram, and Quetelet. 828. Pilgram. 836. Pertz® and Quetelet. 859. Feb. Bouquet, Quetelet, and Boguslawski. “Mar. 30. —-Pertz, Quetelet, and Boguslawski. 840. April 2. Bouquet, Pertz, and Pilgram. és .“ 2. Quetelet and Boguslawski. 842.. Mar. Bouquet, Pertz, Quetelet, Bocusl. oC Mar.18. Pertz, Bouquet, Quetelet, Bogusl. a May 6. Pertz, Bouquet, Quetelet, Bogusl. € x. Rome. Tylkowsky. Frobes. 848. Dec. 2. Pertz, Bouquet, Quetelet, Bogusl. 849. Jan. 2. Pertz, Bouquet, Quetelet, Bogusl. 855. Oct.17. Pilgram. 859. Aug. Leibnitz,* Frobes, Mairan, Pilgram. “ Sept. Leibnitz, Frobes, Mairan, Pilgram. co Oct: Leibnitz, Frobes, Mairan,' Pilgram. 861. Mar. 10. Bouquet, Pertz, Quetelet, Bogusl. 869. Pilgram. 870. Bouquet,? Quetelet, Pilgram, Boguslawski. 871. Aug. 14.7 Lycosthenes, Frytschius, Frobes. “ “14, Mairan, Chasles, Boguslawski. Si Bouquet, Quetelet, and Boguslawski. 918 “Feb. 7. Bouquet, Duchesne,® Quetelet, Bogusl. 919. Feb. 7. Pertz, Quetelet, and Boguslawski. 927. March. Quetelet® and Boguslawski. 930. Feb.19. France. Lycosthenes, Mairan, Frobes. 1 He quotes Bouquet. TIL. 139 et V. 72. 2 Mairan thinks it uncertain whether this appearance was in 808 or 809. Traité, p. 190. 5 Quetelet quotes his Monumenta Germaniz Historicx, IT. 226. + Miscellanea Berolinensia ad Incrementum Scient. I. 137. 5 Mairan quotes the Annals of St. Bertin for the Luminous Phenomena of this year. Boguslawski ranks them as star- showers. ® Pendant plusieurs nuits le ciel est rouge comme du sang : 7 This is the date to which Mairan reduces IV. Idus aie 8 Historie Francorum Scriptores. III. 474. ® He quotes Reiffenberg. Mém. de 1’Acad. Brux. VIL. 63. Recueil des Historiens des Gaules., &e, AURORA BOREALIS. 930, Feb.19. Acad. Coll. Chasles, Boguslawski. 937. Feb. 14. Bouquet, Duchesne, Pertz, Quetelet. 940.? Dee. Bouquet, Quetelet and Boguslawski. 956. Sept. 7. Frobes,) Mairan and Acad. Coll. 970. Lycosthenes, Pilgram, and Boguslawski.? 978. Oct. 28. Frytschius, Frobes, Mairan,’ and P. 979. Noy. 2. Lycosthenes, Wolffius, and Frobes. Zahn, Mairan,* Acad. Coll. and Quetelet. 992. - Oct. 21. Pilgram. « Dee. Calyisius and Mairan. 993. Jan. 6. Short® and Mairan. és Dec. 26.8 Leibnitz, Frobes, Mairan, Pilgram. 998. Dec. 19. Lycosthenes, Frobes, Mairan, Acad. 1014. Noy. 2. Frytschius, Frobes, Mairan, Acad. “ Dec. 29. Boué,’? and Acad. Coll. 1039. April12. Lycosthenes, Frobes, Mairan. KC Pilgram, Acad. Coll. and Chasles.® 1041. Frytschius and Frobes. 1093. Jan. 13. Pilgram. 1095. Feb. 24. Godin,? Mairan, and Pilgram. 1096. Mar. 9. Wolffius, Frobes,!° and Mairan. C “ 9. Pilgram and Acad. Coll. 1098. Sept. 29. Ingram™ and Pilgram.? “ Oct. 38. Lycosthenes, Frobes, Mairan, Acad. 1099. Mar. 2. Lycosthenes, Frobes, Mairan, Acad. 1104. Frytschius, Lycosthenes, Frobes. 1105. Dee. 29. Short, Mairan, and Acad. Coll. 1106. Feb. 19.” Jtaly. Lycosthenes, Frobes, Mairan. £ « 19, Pilgram, Acad. Coll. and Quetelet. 1114. Frytschius and Frobes. (Doubtful.) 1115. April 24. Lycosthenes, Frobes, Mairan, Acad. 1116.2 Lycosthenes, Frobes, Pilgram, and Chasles. 1117. Feb. 22.1 Liege. Lycosthenes and Frobes. 1 Baluzius. Chronic. Floriar. p. 305. 2 This is the appearance which Frobes assigns to the year 971. 3 Mairan (p. 191.), quotes Le Chronique Hirsaugiense de l’Abbe Trithéme. The date here given is probably in old style. * Mairan quotes the Chronique de Liechtenaw. (Urspergen- sis.) The original date is V. Kal. Noy. ® A General Chronological History of the Air, Weather, etc. II. 178. ® Probably Old Style. 7 Sitzungsberichte der Kaiserl. Akad. Wien. XXII. 13. ® Boguslawski is probably correct in not regarding this as an aurora. ® Mém. de l’Acad. Paris, 1723, p. 296. in old style. 19 In Chronico Urspergens. (Liechtenaw,) pp. 240 et 245. 11 The Saxon Chronicle. pp. 317-8. 2 This was a star-shower and not an aurora. 18 We may doubt with Boguslawski whether this was an aurora. 14 In Chronico Urspergens. (Liechtenaw,) p. 274. The date is probably ON THE PERIODICITY OF THE AURORA BOREALIS. 1117. Feb. 22. Mairan, Pilgram, and Acad. Coll. s Nov. «x. Short. S Dee. «x. Short. « «16. Ingram. [Saxon Chronicle. p. 338.] 1117. Dee. 26. Palestine. Lycosthenes and Frobes.1 ce Mairan, Acad. Coll. Chasles, Boguslawski. 1118. Jan. 13. Pilgram. f Dec. 19. Lycosthenes, Mairan,? and Bouéd. 1120. Leodium. Lycosthenes, Frytschius, Frobes. 1122. Dee. 7. Ingram. 1132. Jan. 11. Ingram. 1150. Pilgram. 1157. Lycosthenes, Frobes, and Pilgram. & Chasles and Boguslawski. 1180. Pilgram. 1188. Dee. 20. Canterbury Gervasius. 1192. Pilgram. 1193. Jan Short. ARG) iy Short. fc 7 Nove Short. 1200. Aug. 19. Baluzius,* Frobes, Mairan, Acad. 1203. April 1. Pilgram, Pfaff, Boguslawski. 1204. Pilgram. 1251. Frobes.® 1262. Pilgram. 1269. Dee. 13. lLycosthenes, Cromerus,’ Frobes. « «“ 13. Mairan, Acad. Coll. Boguslawski. 1280. Frytschius and Frobes. 1307. Mar. 6. Lycosthenes, Frobes, and Mairan. «“ 0 6. Acad. Coll. Chasles, Boguslawski. 1309. ? Lycosthenes, Chasles, and Bogusl. 1325. May 30. Florence. Frobes, Mairan, Acad. 1351. Dee. Lycosthenes, Frobes,’ and Pilgram. OLE 2 nee Chasles and Boguslawski. 1352. Oct. 30. Franciscus, Frobes, Mairan, Acad. 1353. Aug. 19. Franciscus, Frobes, and Mairan. = co: 19. Pilgram and Acad. Coll. 1354. Mar. 9. Lycosthenes, Franciscus Frobes. 1 Compt. Rend. VII. 709. 2 Mairan quotes this example from Lycosthenes, but it is probably the same as the aurora of Dec. 26, 1117. Traité &c., p. 192. 3 Splendor magnus visus est in Cantuarid nocte media XIII. Kal. Jan. Twysden’s Decem. Scriptores. I. 1538. * Miscellan. Chronicon Cremonense. Lib. IT. 307. 5 Wiirtemberg Jahrbuch fur. Vaterland. Geschichte. 1850. I. 80. 6 Mairan does not rank this among the auroras. 7 De Rebus Gestis Polon. Lib. IX. This is the same aurora as Boué ascribes to Dee. 6. 8 Franciscus. Der Wunderreiche Ueberzug unsrer Nieder- Welt &e. % See Traité de l’Aurore Boreale par Mairan, p. 183. 19 1554, Mar. 9. Mairan and Acad. Coll. 1361. Dec. 12. Pilgram. 1375. Frytschius, Lycosthenes, and Frobes. % Chasles and Boguslawski. 1399. Pilgram. 1437. Mar. 16. Pilgram. 1446. Feb. 5. Lenzburg, &c. Lycosthenes, Frobes. cs “5. Mairan, Acad. Coll. and Boguslawski. 1461. July 23. Mairan? and Pilgram. 1465. Nov. 18. Mairan and Pilgram. 1499. May 30. Lucerne, Switz., Lycosthenes. s “ 30. Frobes, Mairan, and Acad. Coll. 1514. Jan. 22.2 Lycosthenes, Frobes, Mairan, Acad. 1518. Jan. 3. Saxony. Lycosthenes. < “© 3. +Frobes, Mairan, and Acad. Coll. 1518. =. Cromerus and Frobes. 1520. Sept.13. Vienna and Erfurt. Lycosthenes. * oo Frobes, Mairan, Pilgram, Acad. Coll. Bogusl. xe Dec. 2. Frobes, Mairan, and Acad. Coll.® 1527.6 Aug. 11. Boué. “ Oct. 20. Westrich. Lycosthenes, Frobes. & « 20. Mairan, Pilgram,’ and Acad. Coll. a: Dec. 11. Boué. 1529. a. Ulyxibona. [Lisbon 2] Nihusius, Frobes. & Jan. 18. Germany. Lycosthenes, Meurerus. « Frobes, Mairan, Acad. Coll. Boguslawski. Lisbon, Portugal. Lycosthenes. = Frobes and Boguslawski. Innspruck. Lycosthenes, Frobes,’ Pilgram. June 12. Schleswig, Holstein. Lycosthenes. = Finceleus, Frobes,® Mairan, and Acad. Coll. 1535. May 26. Lausitz. Lycosthenes, Frobes. 3 s 26. Mairan, Acad. Coll. Boguslawski. o xz. Weimar. Lycosthenes, Nihusius, Frobes. 1 On this phenomenon Frobes remarks : “ Dubium equidem, nisi fallor, propter ipsius narrationis conditionem, videtur, de- beantne pro Aurora Boreali, an pro Tempestate quidam sonora et fulgurante haberi, quorum hie mentio sit, nocturna cwli spec- tacula.” 2 This date, probably in old style, is from the Chronique de Lonis XI., p. 12. 8 This was not probably an aurora. * Weidler. Commentat. de Aurora Boreali, p. 64. 5 Urstisius Annal. Bas. Lib. VII. C. 9. and Wagner. Historia Nat. Helvetie Curiosa., p. 363. 6 Bjusmodi visa (acies in clo dimicantes) scribit Melanca- thon in Germania ab anno 1524 ad 1548 saepissime spectata. Tylkowsky. Physica Curiosa. P. IIL, p. 176. 7 In Pilgram and the Acad. Coll. the date is Oct. 11. 8 Fincelius. De Miraculis. Jonston. Thaumatographia Natur. Class III. Cap. 12. ® Teubner. De Armorum Militumque Simulacris, &e. ! ON THE PERIODICITY OF THE AURORA BOREALIS. Spain. Fincelius, Lycosthenes. Frobes, Mairan, and Acad. Coll. Italy. Fincelius, Lycosthenes, &c. Frobes, Mairan and Acad. Coll. Lycosthenes, Frobes,’ Pilgram. Germany. Lycosthenes, &e. Frobes, Mairan, and Acad. Coll. Wurtemberg. Lycosthenes, Wolffius. | Frobes and Boguslawski.* Pfortzheim. Lycosthenes, Frobes. Mairan, Acad. Coll, Boguslawski. Saxony. Lycosthenes, Boguslawski. Poland. Lycosthenes, Franciscus, &e. Frobes, Mairan, and Acad. Coll. Meissen. ycosthenes, Frobes. Mairan, Acad. Coll. Boguslawski. Fincelius, Franciscus, Liebknecht. Helvetia. Lycosthenes, Fincelius, Frobes, Mairan, and Acad. Coll. Saxony. Lycosthenes, Fincelius. Frobes, Mairan, and Acad. Coll. Saxony. Decimator,* Milichius.® Frobes, Mairan, and Acad. Coll. Padua. Toaldo.® Kirch, Mairan, and Acad. Coll. Lisbon, Lycosthenes, Frobes. Mairan, Acad. Coll. Boguslawski. Kirch, Mairan, and Acad. Coll. Wittemberg. Eberus,’ Schmidt. a Frobes, Fincelius, Mairan, and Acad. Coll. 1536. Feb. 16. “ “ 1 6. 1537e) Heb: 10: Gs “ 10. 1538. Germany. toate Jan. -os “ “ 38. 1542. 1543. May 13. “ NDE 1545. Feb. zx. ec April 7. “ “ ie 1546. Feb. 19. “ “ 19. “Hungary. 1547. July 31. “ “ 3 1 é ce Oct. 10. “ “ 10. 1548. Nov. 15. “ “ 15. 1549. April. « Sept. 30. 1551. Feb. 6. “ “ 6. 35 Sept. 11. ce Oct AF 1554. Feb. 10. “ “ 10. crn Ages (2h “ “ Dr « Aug. 14. ee Aug. 21. 1555. Mar. '22. “ “ POF < Sept) 2: W55Orm can. e208 “ “ 20. “. Sept. 14. “ “ 1 4, Chalons. Lycosthenes, Frytschius. Frobes, Mairan, and Acad. Coll. Bohemia. ¥rytschius, Lycosthenes. Mairan, Pilgram, and Boguslawski. Stolpen. Lycosthenes, Fincelius, B. Kirch, Mairan, and Acad. Coll. Thuringen. Lycosthenes, Frobes. Mairan, Acad. Coll. Boguslawski. Kirch, Mairan, and Acad. Coll. Bavaria. Lycosthenes, Frobes. Mairan. Acad, Coll. Boguslawski. Ciistrin. Fincelius and Lycosth. Mairan, Pilgram. Acad. Coll. B. 1 Maiolus. Dierum Canicularium, Colloq., I. 32. 2 Cardan. De Demon. 8 Schmidt. In Chron. Cygn., 11.337. Lehmann. In Chron. Misn., p. 399. * Epit. Meteor., p. 27. 5 Commentar. in Plinium. p. 209. § Rozier. Journ. de Phys., &c., XXIV. 7-8. 7 Calendario Histor., &e. pagum Teucheln. Multi crederent ardere vicinum “ in 1557. 7 Rivander. Mar. 26. 26. Dec. 4. “ 4, Feb. 11. ian 13 Voigtland. Lehmann. Frobes, Mairan, and Acad. Coll. Jtaly. _Franciscus. Frobes, Mairan, and Acad. Coll. London. Halley, Pilgram. Bohemia and Saxony. Thompson,’ Boguslawski. April 19. Jans 6? Germany. Jan. 6.5 “ wie Mar. 8. Sy iS? Jan. 23. Feb. 4. Feb. 27. Sept. 9. Oct. 16. and Acad. Coll. - Zurich. Wolf. Zurich. Wolf. Zurich. Wolf. Zurich. Wolf. Zurich. Wolf. Zurich. Wolf. Zurich. Wolf. Zurich. Wolf. Zurich. Wolf. Kirch, Mairan, Moestlin,® Acad. Coll. Baknang, Wurtemberg. Moestlin, F’s. Mairan, Pilgram, and Acad. Coll. Wurtemberg. Moestlin, Frobes, M’n. Halley, Pilgram, and Acad. Coll. Wurtemberg. Moestlin, Frobes, M’n. Halley, Pilgram, and Acad. Coll. 1 This is given erroneously by Mairan as March 15. 2 Scheuchzer. Biblioth. Scrip. Hist. Nat. p. 75. 8 Rerum Anglicarum et Hybernicarum Annales, p. 263. 4 A General Chronicle of England, p. 678. - 5 Mairan quotes this aurora from Frobes, as upon Sept. 28. ® Consideratio et Observatio comete aetherei, &c. 21 1580. Sept. 5. Boud. 1591. 1 Erklarung der Land-Tafel von Preussen. Be ()s “20, Ocitalt “ lve Feb. 26. 26. April 12. 14. SiG: Sept. 5. Oct. 24. Nov. 18. cA: Mar. 16. Gs 17. 5 its}. gilts), April 10. “ “ “ it3 Noy. “ Sept. Oct. Feb. Dee. Jan. Mar. 6 12. 8. Sk April 12. Mar. 30. He 7: Mar. 23. 30. April 12. 12. 12. 29. 5 bo S b 1% 13. 5. . 14. 15. 16. 16. Wurtemberg. Moestlin, Frobes, M’n. Halley, Kirch, Pilgram, Acad. Coll. Wurtemberg. Moestlin, Frobes, M’n. Halley, Pilgram, and Acad. Coll. Kirch and Mairan. Zurich. Wolf. Halley, Mairan, Moestlin, Pilgram. Wurtemberg. Moestlin, Frobes, M’n. Halley, Pilgram, and Acad. Coll. Germany. Frobes, Kirch, Mairan. Wurtemberg. Moestlin, Frobes, M’n. Halley, Pilgram, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Brabant. Frobes, Mairan, Acad. C. Zurich. Wolf, Kirch, Mairan, Acad. Kirch, Mairan, and Acad. Coll. Zurich. Wolf. Kirch, Mairan, and Acad. Coll. Kireh, Mairan, and Acad. Coll. Zurich. Wolf. Meissen. Lehmann. Frobes, Kirch, Mairan, Acad. Coll. Kirch, Mairan, and Acad. Coll. Prussia. Hennenberger.? Frobes, Kirch, Mairan, Acad. Coll. Zurich. Wolf, Kirch, Mairan, Acad. Kirch and Mairan. Zurich. Wolf. Kirch, Mairan and Acad. Coll. Zurich. Wolf. Zurich. Wolf, Kirch, Mairan, A. C. Kirch, Mairan and Acad. Coll. Zurich. Wolf. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Brandenberg. F robes.” Kirch, Mairan, and Acad. Coll. Upsal. Celsius, Frobes, M’n., A. C. Hondorff, Frobes, Mairan, A. C. Hondorff, Frobes, Mairan, A. C. Hondorff, Frobes, Mairan, A. C. Kireh, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. * Berne. Wolf. Zurich. Wolf. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. 2 Hondorfli Calendarium Sanctorum, &c., p, 102. 1592. Mar. 1593. Oct. “ “ “ “ “ “ “ “ “ “ “ “ 1596. April 1600. Dee 1602. June 1603, Sept. “ Noy. 1605.? Nov. “ “ se Dec. 1606. Sept. “ “ 1607. Nov 1608. Nov. “ “ 1609. Mar. “ “ “ “ 1612, Aug. 1614. July 1615. Oct. 1621. Feb. “ Mar. “ Sept. “ “ se Sept. “ “ x Oct. 1622. Jan. “ June 1623. Jan. “ “ 12. 12. 22. 22. 13. 24. 10. 12. 16. ON THE PERIODICITY OF THE AURORA BOREALIS. Frobes, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kireh, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Schmidt, Lehmann, F., M., A. C. Schmidt, Frobes, Mairan, and Acad. Zurich. Wagner,’ Frobes, Mairan. Zurich. Wagner, Frobes, Mairan, Zurich. Wolf. [Acad. Coll. Mayence. Serrarius.? Schmidt, F. Paris. Mairan, Pilgram, and Acad. Mayence. Serrarius. Pilgram. Frobes, Mairan, and Acad. Coll. Frobes,® Mairan, and Acad. Coll. Serrarius,® Frobes, Mairan, Acad. Kauffbeuren, Suabia. Bernegger. Frobes, Mairan,’ and Acad. Coll. Leuwarden. Nihusius. Frobes. Academy’s Collection. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Basle. Wagner, F’s., M. and A. C. Paris. La Motte le Vayer, Mairan, Acad. Coll. {and Pilgram. Kirch and Mairan. Zurich. Wolf. Neuchatel® Pilgram. Liebknecht, Frobes, Kirch, Mairan, France. Gassendi.’ [Thompson, A.C. Frobes, Mairan,” and Acad. Coll. Zurich.? Wolf. Kirch, Mairan, and Acad. Coll. Zurich. Wolf. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. 1 E Snizeri Chron. Helvet., p. 125. 2 Epistole ad John Kepler, &e., p. 350. 8 Journal du Regne de Henry IV. de P. de l’Etoile, IT. 88. * Mairan takes both these dates from Frobes unchanged. 5 Frobes quotes, ‘ Le Mercure Frangois, &c., p. 82. ® Acta Erudit. Leipsic, 1719, p. 8. 7 Mairan and Pilgram assign this aurora to Noy., 1607. Traité &c. p. 201. 8 Bull. de l’Acad. Brux. V., 283. © Oeuvres, II. 108. 19 Mairan places this aurora on Sept. 21. that this and the preceding record refer to the same aurora. 1623. “ 1625. “ “ “ “ 1626. “ “ “ Frobes intimates 1628. iW 18. 13. 17. 17. 1h ff 12. 16. 26. 29. 30. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Joach im, Bohemia. Frobes, M.,A.C. Lehmann. Frobes, Mairan, and Germany. Kepler [ Acad. Coll. Kirch, Mairan, and Acad. Coll. Joachim. Lehmann, F., M., A. C. Anhalt. Frobes, Mairan, Acad. Coll. Holland. Franciscus. Frobes,? Mairan, and Acad. Coll. Mairan, Short, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Mairan, Short, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Mairan, Short, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kireh, Mairan, and Acad. Coll. Joachim, Bohemia. Lehmann. Frobes, Mairan, and Acad. Coll. Joachim. Lehmann. Frobes, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. ~ Pfaff. Boguslawski.2 Boué. Pfaff. Boguslawski. Boué. Mairan, Short, and Acad. Coll. Mairan, Short, and Acad. Coll. Mairan, Short, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch and Mairan. Meissen. Jonston.t Frobes. Zurich. Wagner. Frobes. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Mairan, Short, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Mairan, Short, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Mairan, Short, and Acad. Coll. Kirch, Mairan, and Acad. Coll. 1 Thompson’s Meteorology, p. 350. 2 Baudartius, Historia Eccles. et Polit. Lib. XVI. 8 Wiirtemberg Jahrbuch fur 1850. I. # Thaumatographia Naturalis, &c. 1630. Feb. “ “ “ “ “ “ « June “ “ 1732. Nov 1633. May « June « Dec. “ “ 1634. Jan “ “ « Feb “ “ “ “ 1637. Aug. “ “ 1638. Jan. “ “ 1640. Jan. 1643. Nov “ “ 1644. Mar. 1645. April “ “ 1646. Nov “ “ 1650.? Jan 1654. Mar. o “ 1655. July “ “ 1757. Jan. «April “ “ 1660. Dee. 1661. Jan “ “ oe April 1662. Dee. “ “ 1663. Nov. 15. 15. 9. ON THE PERIODICITY OF THE AURORA BOREALIS. Joachim. Lehmann. Frobes, Mairan, and Acad. Coll. Spitzbergen. Boué, Mairan, Acad. Tubingen. Schickard, Frobes, Kirch. Pfaff, Boguslawski, Boué. Plaff, Boguslawski, Boué. [bow. Paris. Godin. Copenhagen. Horre- Lehmann, Frobes, M., and A. C. Lehmann, Frobes, M., and A. C. Spitzbergen. Zorgdrager. Frobes and Mairan. Acad. Coll. Spitzbergen. Zorgdrager. Frobes, Mairan, and Acad. Coll. Spitzbergen. Zorgdrager. Frobes, Mairan, and Acad. Coll. Wolckenstein. Lehmann. Frobes. M. Meissen and Bohemia. Lehmann. Frobes, Mairan, and Acad. Coll. Meissen and Bohemia. Lehmann. Frobes, Mairan, and Acad. Coll. Lehmann, Frobes, Mairan, and Boguslawski.? Boué. [Acad. Coll. Saxony. Franciscus, Lehmann, F. Annaberg, Saxony. Lehmann, F. Dunckelspield. Franciscus. Frobes, Mairan, and Acad. Coll. Silesia. Franciscus. Frobes, Mairan, and Acad. Coll. Basle. Wagner. Frobes, Mairan, and Acad. Coll. Leipsic. Franciscus. Frobes,4 Mairan, and Acad. Coll. Poland. ‘Tylkowsky. Frobes, Mairan, and Acad. Coll. Kirch, Mairan, and Acad. Coll. Meissen. Lehmann. Frobes, Mairan, and Acad. Coll. Hungary. Lehmann. F robes. Glarus and Vadisvilla. Wagner.® Frobes, Mairan, and Acad. Coll. Prussia. Schulzius. Franciscus. Frobes, Mairan, and Acad. Coll. Scheibenberg. Lehmann. Frobes, Mairan, and Acad. Coll. Scheibenberg. Lehmann. 1 Encye. Method. I. 453. 2 De Piscatu Groenland, Leipsic, 1723, p. 320. ® Schles. Chron., Noy. 12, 1841. 4 Limner. De Nundin. Lips. Relat. 5 This was probably a meteor. 1663. Noy. 1664. April “ “ 1665. April “ “ oe Aug. 1666. Jan. “ “ 1671. Nov “ “ 1672. Jan. “ “ 1676? Feb. sé Mar. 1677. Novy. “ “ Dec. “ “ 1680. Sept. “ “ 1682. Nov “ “ fs Dec “ “ 1683. Jan sf Aug. “ce “ 1684. Mar “ “ ke Nov “ “ 1685. April 1686. Feb. “ “ & June “« July “ Oct. 1687.2° Denmark. Horrebow. 9. 18. 18. 18. 18. 23. dl. dl. 29. 29. 19% 29. 29. 23 Frobes, Mairan, and Acad. Coll. Scheibenberg. Lehmann. Frobes, Mairan, and Acad. Coll. Baltic Sea. Scheffer. Franciscus. Frobes, Mairan, and Acad. Coll. Upsal. Celsius. Frobes, Mairan,} Scheibenberg. Lehmann. [A. Coll. Frobes, Mairan, and Acad. Coll. Bischofszell, Switz. Wagner. Frobes, Mairan, and Acad. Coll. Cracow. Cromerus. Frobes, Mairan,? and Acad. Coll. Zurich. Frobes, Mairan, Acad. C. Zurich. Frobes, Mairan, Acad. Coll. Rostock. Franciscus. Frobes, Mairan, and Acad. Coll. Annaberg, Saxony. Lehmann. Frobes, Mairan, and Acad. Coll. Chemnitz. Lehmann. Frobes, Mairan and Acad. Coll. Dantzig. Wevelius.® Frobes, Mairan, and Acad. Coll. Meissen.?, Waldschmidt. Lehmann. Frobes, Mairan, and Acad. Coll. Frobes, Mairan, and Acad. Coll. Germany. Weigelius,> Lehmann. Frobes, Mairan, and Acad. Coll. Meissen. Lehmann.® Frobes, Mairan, and Acad. Coll. Meissen. Lehmann. Frobes, Mairan, and Acad. Coll. Lehmann, Frobes, Mairan, A. C. Mittelheim. Moeren.’ Frobes. Mairan, Pilgram, and Acad. Coll. Mairan, Short, and Acad. Coll. Mairan, Short, and Acad. Coll. Meissen. Vulpius. Guettner.® Frobes, Mairan, and Acad. Coll. Pilgram, Mairan. 1 Acta Lit. Suecia. II. 50. 2 Mairan understands Frobes as meaning Jan. 1673. 3 Acta Erudit. Leipsic, 1682, p. 391 et 1685, p. 141. # Diss. Meteori Ignei in Aere nuper conspecti, &c. 5 Von der Wiirkung des Gemiiths, &c. 6 This and the supposed aurora of Nov. 23 were probably meteors. 7 Miscell. Curiosa. 1686. VII. 215. ? 8 Acta Erudita et Curiosa. XX. 716. ® Cassini states that the aurora appeared at the end of June and continued till July 10. Eneye. Method. — Physique, I. 352. Also Traité &c. par Mairan, pp. 35 et 203. ON THE PERIODICITY OF 1690. Oct. Short and Mairan. - Novy. Short and Mairan. se Dec. Short and Mairan. 1692. April 12. Frobes, Mairan, and Acad. Coll. « May 22. Lehmann, Frobes,’ Mairan, Acad. “ Sept. 14. Breslau. Grebner.? Frobes. 1693. Nov. 10. Lehmann and Frobes. a « 10. Mairan and Acad. Coll. u Nov. 22. Breslau. Grebner, Frobes, Mairan, 1694. Mar. 31. Breslau. Grebner, Frobes, Mairan, < April 4. Breslau. Grebner, Frobes, Mairan, 1665. Oct. 5. Breslau. Grebner, Frobes, Mairan, ce « 12. Breslau. Grebner, Frobes, Mairan, ~ « 31. Breslau. Grebner, Frobes, Mairan, < Noy. 20. Breslau. Grebner, Frobes, Mairan, 1696. May 12. Breslau. Grebner, Frobes, Mairan, “ Sept. 26. Breslau. Grebner, Frobes, Mairan, ~ Nov. 6. Breslau. Grebner, Frobes, Mairan, x “« 18. Breslau. Grebner, Frobes, Mairan, 1697. Aug. 18. Meissen and Holstein. Lehmann. = < 18. Frobes, Mairan, and Acad. Coll. 1698. Feb. 24. Breslau. Grebner, Frobes, Mairan, = “ 26. Breslau. Grebner, Frobes, Mairan, « May 18. Frobes, Mairan, and Acad. Coll. = Sept. 30. Rossa.°? Lehmann, Mairan, Frobes, ts Noy. 15. Breslau. Grebner, Frobes, Mairan, | ~ “ 27. Breslau. Grebner, Frobes, Mairan, | “ Dec. 7. Breslau. Grebner, Frobes, Mairan, | ec « 23. Breslau. Grebner, Frobes, Mairan, | cS « 28. Breslau. Grebner, Frobes, Mairan, | < Jan. Breslau. Grebner, Frobes, Mairan, | = Feb. 17. Breslau. Grebner, Frobes, Mairan, 1699. Feb. 23. Breslau. Grebner, Frobes, Mairan, “ c: 25. Breslau. Grebner, Frobes, Mairan, | «April 17. Breslau. Grebner, Frobes, Mairan, | = Ee 20. Breslau. Grebner, Frobes, Mairan, | < “ 21. Breslau. Grebner, Frobes, Mairan, - cS 28. Breslau. Grebner, Frobes, Mairan, « June 18. Breslau. Grebner, Frobes, Mairan, Mairan places this by mistake on March 22. Traite &c., p. 471. 2 In Diario Meteorol. Wratislav. p. 7, &c. In regard to the numerous observations of supposed auroras recorded by Grebner, between 1692 and 1700, Frobes remarks: “ Dubium est, fateor, noctemne insigniter serenam (qui siderea vocari passim hic solet) an luminis borealis spectaculum aliquod noctis sublustris vocabulo auctor significaverit. Sed nolui tamen interim quamquam dubias observationes hasce prorsus omittere> ne scilicet curatius hoc | quicquid rei est, explorandi ansam mihi atque aliis denegasse videar,” p.62. Acad. Coll. is omitted for want of room on Greb- ner’s dates, and on Sept. 30. 3 Near Freiburg. THE AURORA BOREALIS. 1699. June 26. Breslau. Grebner, Frobes, Mairan, «July 23. Breslau. Grebner, Frobes, Mairan, « July 26. Breslau. Grebner, Frobes, Mairan, « Aug. 14. Breslau. Grebner, Frobes, Mairan, « “ 19. Breslau. Grebner, Frobes, Mairan, - “ “ 21. Breslau. Grebner, Frobes, Mairan, S “« 22. Breslau. Grebner, Frobes, Mairan, . “« 24, Breslau. Grebner, Frobes, Mairan, S “« 26. Breslau. Grebner, Frobes, Mairan, CS “ 27. Breslau. Grebner, Frobes, Mairan, “ Sept. 16. reslaw. Grebner, Frobes, Mairan, = “ 17. Breslau. Grebner, Frobes, Mairan, - “ 18. Breslau. Grebner, Frobes, Mairan, = “ 19. Breslau. Grebner, Frobes, Mairan, “ “ 21. Breslau. Grebner, Frobes, Mairan, =e “ 22. Breslau. Grebner, Frobes, Mairan, « 24. Breslau. Grebner, Frobes, Mairan, “ Oct. 9. Breslau. Grebner, Frobes, Mairan, “ “ 18. Breslau. Grebner, Frobes, Mairan, « “ 21. Breslau. Grebner, Frobes, Mairan, = « 22. Breslau. Grebner, Frobes, Mairan, ee « 24, Breslau. Grebner, Frobes, Mairan, “ Noy. 10. Breslau.- Grebner, Frobes, Mairan, = “ 15. Breslau. Grebner, Frobes, Mairan, “ “ 18. Breslau. Grebner, Frobes, Mairan, = “ 21. Breslau. Grebner, Frobes, Mairan, = «“ 23. Breslau. Grebner, Frobes, Mairan, = «“ 24. Breslau. Grebner, Frobes, Mairan, “ Dee. 14. Breslau. Grebner, Frobes, Mairan, aS “ 15. Breslau. Grebner, Frobes, Mairan, “ 17. Breslau. Grebner, Frobes, Mairan,? 1701. Valencia, Spain. Rico.* 1702. May 29. Abo, Finland. Jechonius.* = « 29. Frobes and Mairan. 1704. Pilgram. 1Between 1700 and 1751, the Collection Academique appears to be merely a transcript from Mairan’s catalogue of auroras, with occasionally an accidental error, mostly omissions. The auroras of Noy. x.1709, and March x. 1711, are given as Noy. 11 and March 11. The auroras of April 11, 1716, April 10 and 11, 1717, of Oct. 11, 1718, of Feb. 11, 1719, of Feb. 11 and April 11, 1720, of Feb. 11, 1721, of Jan. 17, 1724, are all omitted. The auroras of May 1 and 3, 1728, are given as the aurora of May 13. An aurora on May 26, 1737, is interpolated, and the auroras of Noy. 26 and 30 of that year are omitted. The auroras which belong to March and April, 1741, are repeated for 1742, and the actual auroras of | March, 1742, are omitted. Since the date of Mairan’s catalogue, | auroras are given for Feb. 4, 1759, at Berlin and Freybourg, and for Feb. 8, 1759, at Paris. 2 Mem. de l’Acad. Cience. Madrid. III. 77. 3 In dem Unyorgreiflichen Bedencken iiber das Zu Abau in Finland—am Himmel wahrgenomene Wander-und Feuer-Zei- chen. ON THE PERIODICITY OF THE AURORA BOREALIS. 25 1704. Dec. 28. Frobes and Mairan. 1706. Sept. or Oct. Barret. 1707. Feb. 1. Copenhagen. Roemer. Mairan.? “2. Copenhagen. Roemer. Boué. « 12. Frobes and Mairan. © ; Mar. 1. Copenhagen. Roemer.’ Mairan. 6. Berlin. Kirch* Schomberg. Seidelius.° 17. Frobes and Mairan. 18. Frobes and Mairan. 20. Frobes and Mairan. 31. Upminster. Derham. Jreland. Neve.® . 16. Frobes and Mairan. 18. Frobes and Mairan. 21. Berlin. Kirech. Mairan. 27. Frobes and Mairan. 29. Berlin. Kirch. Mairan. . 24. Frobes and Mairan. 27. Berlin. Kirch. Ireland. Neve! 27. Mairan and Thompson. 1708. . 20. London. Halley.2 Mairan. 21. London. Halley.® . 15. North Sea, 66° Lat. Mairan.” 22. Frobes and Mairan. 1709. Oct. 18. Frobes and Mairan. Noy. «x. Frobes and Mairan. Dec. 19. Frobes and Mairan. 1710. Sept. 17. Paris, Vienna, and Pekin.™ Nov. 26. Giessen. Liebknecht. Mairan.” “« 26. Leipsic.. Pilgram. Dec. 7. Frobes and Mairan. Ui ¢(ilj le Mar. x. Giessen. Pilgram. Frobes and Mairan. 1714. Oct. 15. Frobes and Mairan. 1 Phil. Trans., XX VI. 310. 2 Miscell. Berolin., I. 127-131. 8 Thid., 131. 4 Tbid., 132. 5 Tbid., 129. 6 Phil. Trans., XX VI. 310. 7 Ibid. 8 Phil. Trans., XXIX. 419. ® Tbid. 10 Bruyn’s Voyages, V. 299. 11 Boué quotes Frobes. 13 Acta Erud., 1711. VOL. X. 4 Mar. 15. 26: O29: Mar. 2 BOREALIS. Bill Celsius and Mairan. Between Oola and Kilduin. Celsius and Mairan. Between Cola and Kilduin. Between Cola and Kilduin. Kilduin. Croyere. Kilduin. Croyere. Celsius, Frobes, and Mairan. Kilduin. Croyere. Between Kilduin and Cola. Celsius, Frobes, and Mairan. Between Kildwin and Cola. Celsius, Frobes, and Mairan. Croyere. Croyere. Croyere. Croyere. Croyere. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles, Mairan. Cola. Croyere. Cola. Croyere. Cola. Croyere. 1728. Sweden. Celsius, Frobes, and Mairan. Italy. Beecari. Mairan. Salem. Felt. Frobes and Mairan. St. Petersburg. Kraft. The Delisles, Mairan. Sweden. Celsius. Mairan. Utrecht. Musschenbroek.* Mairan, Pilgram. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes, Mairan, Pilgram. Sweden. Celsius. Frobes and Mairan. Utrecht. Musschenbroek. Sweden. Celsius. Frobes, Mairan, Pilgram. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. Utrecht. Musschenbroek. St. Petersburg. Kraft. The Delisles. Berlin. Kirch. Pilgram. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Celsius, Frobes, and Mairan. Celsius, Frobes, and Mairan. St. Petersburg. Kraft. The Delisles. Mairan and Pilgram. St. Petersburg. Kraft. The Delisles, Mairan. St. Petersburg. Kraft. The Delisles, Mairan. St. Petersburg. Kraft. The Delisles, Mairan. 1 Hist. of Salem, II. 2 Tab. Met., 1728. Be ON THE PERIODICITY OF THE Mar. 8. Plymouth, Eng- Huxham Short. « 9, St. Petersburg. Kraft. The Delisles, Mairan. “ 10. St. Petersburg. Kratt. The Delisles. “ 10. Sweden. Celsius. Frobes and Mairan. “ 14, Sweden. Celsius. Frobes and Mairan. “ 90. Utrecht. Musschenbroek. Mairan. « 20. Celsius, Frobes, and Pilgram. “ 26. Frobes and Mairan. “ 927. St. Petersburg. Kraft. The Delisles. “ 27. Frobes and Mairan. “ 98, Sweden. Celsius, Frobes, and Mairan. « 28. Upsal. Burman.’ « 29. Frobes and Mairan. “ 30. Utrecht. Musschenbroek. « 30. Mairan and Pilgram. “ 31. Bologna. Zanotti. Mairan. “ $81. Mairan and Phil. Trans. April 2. St. Petersburg. Kraft. The Delisles. Short. a 2. Berlin. Kirch. Utrecht. Musschenbroek. Plymouth. Tuxham. Jtaly. Zanotti. Celsius, Frobes, Mairan, and Pilgram. St. Petersburg. Kraft. The Delisles. Plymouth. Wuxham. Short. Sweden. Celsius. Frobes and Mairan. Frobes, Mairan, and Phil. Trans. Sweden. Celsius. Frobes and Mairan. Utrecht. Musschenbroek. Jtaly. Beccari. Mairan and Pilgram. “ 12. Utrecht. Musschenbroek. « 12. Mairan and Pilgram. « 15. Mairan and Phil. Trans. Fit rita Bad cROh RS Oo 9 May 1. St. Petersburg. Kraft. The Delisles, Mairan. | s 3. Berlin. Kirch. Mairan. « 30. Italy. Beccari. Mairan. June 7. Frobes and Mairan. “ 95. Berlin. Kirech. Celsius and Frobes. 3. Mairan. Pilgram. July 1. Mairan and Phil. Trans. 3. Mairan. Pilgram. “ 13. Italy. Beccari. Berlin. Kirch: “ 13. Plymouth. Huxham. Phil. Trans. Mairan. Pilgram. “ = 15. Plymouth. Wuxham. Pilgram. Aug. 2. Plymouth. Huxham. « 2. Phil. Trans. and Pilgram. Mairan. “ 25. St. Petersburg. Kraft. The Delisles, Mairan. 1 Amer. Journ., XX XIII. 298. 2 Acta Lit. Suecix, II. 513. Aug. 27. “28: Ca Ploy Ca Va Cee & 10) < 30: Sie Sis « 31 — Ae NSH 5 ee bs « 626. “ D7, LHP PE SZ: S20: < 25. ae atth 30: “ 30 RO SS re ieee ten eo) (RO ROR) ke “ 1 “ 1 “ 1 “ 1 2s Ce ily a ol3. sy ley 1 Comm AURORA BOREALIS. Kilduin. Croyere. Plymouth. uxham. Sweden. Celsius. Frobes and Mairan. Plymouth. Wuxham. Short and Mairan. Upsal. Burman. Celsius, Frobes,and Pilgram. Berlin. Yireh. Mairan. Sweden. Celsius. Frobes. Utrecht. _Musschenbroek. Upsal. Burman. Celsius. Frobes, Mairan, and Pilgram. Kilduin. Croyere. Jpsal. Burman. Frobes and Mairan. Mairan and Phil. Trans. Sweden. Celsius. Frobes and Mairan. Upsal. Burman. Frobes and Mairan. Pilgram. Cola. Croyere. St. Petersburg. Kraft. The Delisles. Italy. Bececari. Berlin. KWirch. Mairan. St. Petersburg. Maier.’ Mairan. Frobes and Pilgram. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes. Mairan and Phil. Trans. Utrecht. Musschenbroek. Sweden. Celsius. Frobes. Mairan, Pilgram, and Phil. Trans. Italy. Beceari. Berlin. Kirch. Mairan. Zurich. Scheuchzer? Mairan. Sweden. Celsius. Frobes. Phil. Trans. and Pilgram, Cola. Croyere. Frobes and Mairan. Mairan and Phil. Trans. Cola. Croyere. St. Petersburg. Kraft. The Delisles. Utrecht. _Musschenbroek. Mairan. Frobes and Pilgram. St. Petersburg. Kraft. The Delisles. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. Plymouth. Huxham. Utrecht. Musschenbroek. Mairan. Upsal. Burman. Celsius. Frobes, Short, and Pilgram. Salem. Felt. Celsius and Mairan. . Petrop., IV. 121. 2 Acta Acad. Nat. Curios., II. 51, Appendix. ON THE PERIODICITY OF THE AURORA BOREALIS. prey Oct. 17. Celsius and Mairan. | Dec. 14. Frobes and Mairan. “ 18. Cola. Croyere. Mairan and Phil. Trans.) “ 15. Cola. Croyere. “ 19. Cola. Croyere. Mairan and Phil. Trans.) “ 27. Cola. Croyere. “ 24. Redbridge. Derham. Mairan. “ 31. Sweden. Celsius. Frobes and Mairan. “« 24. Sweden. Celsius. Frobes and Pilgram. « 25, St. Petersburg. Kraft. The Delisles. 1729. “ 25, Plymouth. Huxham. Short. Jan. 14. Sweden. Celsius. Frobes and Mairan. “25. Mairan. Pilgram. “ 15. Cola. Croyere. “ 26. Plymouth. Huxham. “ 17. Plymouth. WHuxham. Short. “ 26. Cola. Croyere. Phil. Trans. and Mairan. | « 17, (Celsius, Frobes, and Mairan. “ 27. St. Petersburg. Kraft. The Delisles. Mairan. « 17, Pilgram and Phil. Trans. “ 29. Utrecht. Musschenbroek. | “ 18, Celsius and Mairan. “ 29. Cola. Croyere. Mairan. _ 19. Between Cola and Kilduin. Croyere. “ 29. Pilgram and Phil. Trans. “ 90. Frobes and Mairan. “ 30. St. Petersburg. Kraft. The Delisles. cc OUN UihieohesreandeNtaeane « 30. Italy. Beccari. «& 25, Plymouth. Huxham. “ 30. Utrecht. Musschenbroek. |“ 28, Kilduin. Croyere. « 30. Mairan, Pilgram, and Phil. Trans. Feb. 2. Sweden. Celsius. Frobes and Mairan. “« 31. Cola. Croyere. « 3, Kildwin. Croyere. Nov. 2. St. Petersburg. Kraft. The Delisles. “ 3. Sweden. Celsius. robes and Mairan. “« 2. Plymouth. Huxham. Utrecht. Musschenbroek. « 7, Between Kildwin and Cola. Croyere. « 2. Celsius, Frobes, and Mairan. “ 11. Celsius and Mairan. « 2. Pilgram and Phil. Trans. |« 16 Celsius, Frobes, and Mairan. «3. Mairan and Phil. Trans. | © 17. Cola. Croyere. Frobes and Mairan. A: Mairan. Pilgram. « 923. Cola. Croyere. « 5. Upsal. Burman. Celsius. “ 25. Sweden. Celsius. Frobes and Mairan. « 5. Frobes and Mairan. “ 927. Sweden. Celsius. Frobes and Mairan. “« 7. St. Petersburg. Kraft. The Delisles. Mairan.| « 98, Sweden. Celsius. Frobes and Mairan. « 8. Celsius, Frobes, and Mairan. |Mar. 2. Celsius, Frobes, and Mairan. “ 12. Berlin. Kirch. Mairan. “ 15. Sweden. Celsius. Frobes and Mairan. “ 13. Berlin. Kirch. Mairan. “ 16. Sweden. Celsius. Frobes and Mairan. “ 15. Cola. Croyere. “ 25. Sweden. Celsius. Frobes and Mairan. “ 16. Cola. Croyere. “ 27. Celsius, Frobes, and Mairan. “ 22. Cola. Croyere. “ 28. Sweden. Celsius. Frobes and Mairan. “ 22. Sweden. Celsius. Frobes and Mairan. “ 30. Sweden. Celsius. Frobes and Mairan. “ 23. Utrecht. Musschenbroek. Mairan. Apr. 6. Sweden. Celsius. Frobes and Mairan. «“ 23. Sweden. Celsius.2 Frobes. “ 19. Frobes and Mairan. “ 23. Pilgram and Phil. Trans. “22. Plymouth. WHuxham. Mairan and Short. “ 27. Cola. Croyere. “ 24, Sweden. Celsius. Frobes and Mairan. “ 29. Cola. Croyere. “ 27. Sweden. Celsius. Frobes and Mairan. Dec. 2. Italy. Beccari. Mairan. “ 928. Sweden. Celsius. Frobes and Mairan. “« 3. St. Petersburg. Kraft. The Delisles. “ 30. Frobes and Mairan. « 3. Plymouth. Huxham. Mairan and Short. |May 1. Celsius, Frobes, and Mairan. «4, Frobes and Mairan. « 2. St. Petersburg. Kraft. The Delisles. Mairan. “ 7. Cola. Croyere. « 2. Plymouth. Huxham. Sweden. Celsius. Frobes. “ 10. Cola. Croyere. “ 17. Plymouth. Huxham. Mairan and Short. « 22. Celsius, Frobes, and Mairan. 1 Phil. Trans., XXXVI. 137. i # ese a See 2 Boné quotes Celsius for October 11 and 24; but Mairan NASM ee does not mention these days. “ 29. St. Petersburg. Kraft. Frobes. VOL. X. 5 ON THE PERIODICITY OF THE AURORA BOREALIS. Paris? Mairan. Pilgram. Frobes and Mairan. Paris? Mairan. Frobes. Paris? Mairan. Frobes. Berlin. Kirch. Mairan. St. Petersburg. The Delisles. Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Sweden. Celsius. Frobes and Mairan. Oustiong. Croyere. Sweden. Celsius. Paris. Mairan. Frobes. Frobes, Mairan, and Pilgram. St. Petersburg. Kraft. The Delisles. Mairan. St. Petersburg. Kraft. The Delisles. Paris. Mairan. Pilgram. Sweden. Celsius. Frobes. Plymouth. WHuxham. Mairan and Short. Berlin. YKirch. Mairan. Sweden. Celsius. Mairan. Frobes and Mairan. Berlin. Kirch. Sweden. Celsius. Paris. Mairan. Frobes and Pilgram. Frobes and Mairan. Phil. Trans. Mairan. Berlin. Kirch. Mairan. Sweden. Celsius. Frobes. Sweden. Celsius. Frobes and Mairan. Plymouth. Wuxham. Short. Paris. Cassini. Mairan.? St. Petersburg. Kraft. The Delisles. Plymouth. WHuxham. Phil. Trans. Berlin. Kirch. Paris. Mairan. Pilgram. Sweden. Celsius. Frobes and Short. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Berlin. Kirch. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. 1730. Wittemberg. Weidler. Mairan. Sweden. Celsius. Frobes. Mairan, Pilgram, and Phil.Trans. St. Petersburg. Kraft. The Delisles. 1 Acta Lit. Suecie, IT. 611. 2 Mém. de l’Acad. 1729, p. 321. |Jan. 16. Sweden. Celsius. Frobes and Mairan. “ 17. Sweden. Celsius. Frobes and Mairan. “ 26. Sweden. Celsius. Frobes and Mairan. Feb. 3. Sweden. Celsius. Frobes and Mairan. “4. Paris. Mairan. Pilgram. «7. Frobes and Mairan. “« 9. Sweden. Celsius. Frobes and Mairan. “ 10. Sweden. Celsius. Frobes and Mairan. “ 15. St. Petersburg. Kraft. The Delisles. Mairan. “ 15. Geneva. Cramer. Jtaly. Beccari. “ 15. Sweden. Celsius.2 Frobes and Pilgram. « 16. Berlin. (Kireh. Mairan. “ 16. Betw’n Schleusselb’g & St. Petersb’g. Croyere. “ 16. Sweden. Celsius. Frobes. “ 18. Frobes and Mairan. “ 27. Sweden. Celsius. Frobes and Mairan. Mar. 2. Berlin. Kirch. Mairan. 2. Sweden. Celsius. Frobes. 3. Italy. Beccari. Mairan. 6. St. Petersburg. Kraft. The Delisles. “« 6. Plymouth. Huxham. Abo. Spiring.* 6. Paris. Bouillet* Italy. Beccari. 6. Celsius, Frobes, Mairan, and Pilgram. 6. Short and Phil. Trans. “« 9. Sweden. Celsius. Frobes and Mairan. “« 10. St. Petersburg. Kraft. The Delisles. Mairan. “ 11. Bologna. Zanotti2 Mairan. “ 13. St. Petersburg. Kraft. The Delisles. Mairan. “ 13. Bologna. Zanotti and Beccari. “« 15. St. Petersburg. Kraft. The Delisles. Mairan. “ 15. Abo. Spoéring. Celsius and Frobes. “« 16. St. Petersburg. VKraft. The Delisles. “ 16. Mairan and Thompson. “ 17. Frobes and Mairan. “ 18. St. Petersburg. Kraft. The Delisles. “ 18. Bologna. Zanotti. Frobes and Mairan. “ 20. Plymouth. Huxham. Mairan and Short. “ 21. Bologna. Zanotti. Mairan. “ 22. Sweden. Celsius. Frobes. “ 22. Abo. Sporing. Mairan. “ 28. Boué and Mairan.® Apr. x. Phil. Trans. Mairan. “ 7. St. Petersburg. Kraft. The Delisles. Mairan. 1 Phil. Trans. XXXVI. 279. 2 Acta Lit. Suecie, III. A. 106. 8 Acta Lit. Suecix, III. A. 109. * Mém. de l’Acad. 1730. 5 Comm. Bonon. II. Pt. III. 489. 6 Not in any special catalogue. oa ON THE PERIODICITY OF THE AURORA BOREALIS. 35 St. Petersburg. Kraft. The Delisles. Mairan. | Sept.17. 20. Plymouth. Huxham. Berlin. Kirch. Paris. Mairan. Frobes, Pilgram, and Short. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Abo. Spiring. Celsius and Frobes. St. Petersburg. Kraft. The Delisles. Mairan. Jtaly. Beecari. Paris. Mairan. Pilgram. St. Petersburg. Kraft. The Delisles. Mairan. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Spéring. Celsius, Frobes, and Mairan. Abo. Celsius, Frobes, and Mairan. Sweden. Celsius. Frobes and Mairan. Berlin. Yirch. Mairan. St. Petersburg. Kraft. The Delisles. Paris. Mairan. Frobes and Pilgram. Bologna. Zanotti and Beccari. Wittemberg. Weidler. Frobes and Mairan. Frobes and Mairan. Frobes and Mairan. Sweden. Celsius. Abo. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Abo. Spéring. Celsius and Frobes. Sweden. Celsius. Frobes and Mairan. Abo. Spring. Sweden. Celsius. Frobes and Mairan. Abo. Sporing. Celsius, Frobes, and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Abo. Sporing. Sweden. Celsius. Frobes and Mairan. St. Petersburg, Kraft. The Delisles. Mairan. Frobes and Thompson. Sweden. Celsius. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Plymouth. Huxham. Short. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes. Mairan and Phil. Trans. Jtaly. Beccari. Mairan. Sweden. Celsius. Frobes. St. Petersburg. Kraft. The Delisles. Mairan. St. Petersburg. Kraft. The Delisles. Frobes and Mairan. Spéring. Célsius, Frobes, and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. 11. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Paris. Mairan. Pilgram. Sweden. Celsius. Frobes. Sweden. Celsius. Frobes and Mairan. Berlin. Yirch. Mairan. Sweden. Celsius. Frobes. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Pilgram. Sweden. Celsius. Frobes and Mairan. Huxham. Plymouth. Sweden. Celsius. Frobes, Mairan, Short, and Pilgram. Huxham. Plymouth. Short. Sweden. Celsius. Frobes and Mairan. Plymouth. Huxham. Wittemberg. Weidler. Paris. Mairan. Abo. Spring. Sweden. Celsius. F robes and Pilgram. Berlin. Kirch. Abo. Spring. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Pilgram. Wittemberg. Weidler. Paris. Mairan, Abo. Spéring. Celsius and Frobes. Berlin. Yirch. Paris. Mairan. Abo. Spéring. Frobes. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Abo. Spoéring. Pilgram. Boué. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Mairan and Pilgram. Berlin. YKirch. Celsius and Frobes. Frobes and Mairan. St. Petersburg. Kraft. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Pilgram. Mairan and Pilgram. Frobes and Mairan. Paris. Mairan. Berlin. Kirch. St. Petersburg. Kraft. The Delisles. Cambridge, Mass. Winthrop and Greenwood.* Salem. Felt. Philadelphia. Kahn.? Annapolis, Maryland. Lewis. Sweden. Celsius. Frobes and Thompson. Berlin. Yirch. Mairan. 1 Phil. Trans., XXXVILI., 55. 2 Svenska Vetensk. Acad. Handl, XIII. 145. “ “ 9, “« 10. Com IO se es cy Me 18. ils) Oe PALS 22s C75) SE « ~30: “ i x. Dec. 2. C3 8. C3 9. cas “ 14, Ca ales sc 25t a 2905 & 268 Ko 28e Jan. 2. « of “ 2. «10; a> 20: Feb. 4. « 10. See: < 28: Mar. 1. < as f Ze « Ze 1 Or 4. ON THE PERIODICITY OF THE AURORA BOREALIS. Sweden. Celsius. Frobes and Pilgram. Sweden. Celsius. Frobes and Mairan. Abo. Spéring. Pilgram. St. Petersburg. Kraft. The Delisles. Berlin. Kirch. Phil. Trans. Sweden. Celsius. Frobes and Mairan. Phil. Trans. and Mairan. St. Petersburg. Kraft. The Delisles. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. | Celsius, Frobes, and Mairan. Abo. Sporing. Celsius, Frobes, and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Frobes and Mairan. Abo. Spéring. Celsius, Frobes, and Mairan. Sweden. Celsius. Frobes and Mairan. Boué quotes from Celsius. Frobes and Mairan. Sweden. Celsius. Frobes, and Mairan. Ttaly. Beeeari. Mairan. ? Abo. Spéring. Celsius, Frobes, and Mairan. Frobes and Mairan. Abo. Spéring. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Celsius and Mairan. Abo. Spéring. Celsius, Frobes, and Mairan. Frobes and Mairan. Abo. Spring. Celsius, Frobes, and Mairan? Frobes and Mairan. Frobes and Mairan. 1731. St. Petersburg. Kraft. Berlin. Kirch. Mairan. Sweden. Celsius. Frobes. St. Petersburg. Kraft. The Delisles. Mairan. The Delisles. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Bologna. Zanotti and Beccari. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Plymouth. Wuxham. Short. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. See Traite, &c., par Mairan, p. 495. 2 Acta Lit. Suecie, III. B. 44. | Mar. NNER RR POO wwNyws Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Sweden. Celsius. Frobes and Phil. Trans. St. Petersburg. The Delisles. Mairan. St. Petersburg? Kraft. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Sweden. Celsius. Frobes and Phil. Trans. St. Petersburg. Kraft. The Delisles. Mairan. Boué. Mairan and Short. Plymouth. Huxham. Phil. Trans. and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Plymouth. WHuxham. Short. Sweden. Celsius. Frobes and Mairan. Wittemberg. Weidler. Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Sweden. Celsius. -Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Wittemberg. Weidler. Sweden. Celsius. Frobes and Mairan. Plymouth. Huxham. Sweden. Celsius. Frobes and Mairan. Plymowh. Wuxham. Short and Mairan. St. Petersburg. Kraft. The Delisles. Berlin. Kirch. Mairan. Sweden. Celsius. Frobes and Pilgram. Paris? Mairan. Celsius and Pilgram. Wittemberg. Weidler. Paris? Mairan. Pilgram. Paris? Mairan. Pilgram. Paris? Mairan. Pilgram. Sweden. Celsius. Frobes. Phil. Trans. and Mairan. Phil. Trans. and Mairan. St. Petersburg. Kraft. The Delisles. Wittemberg. Weidler. Mairan. Philadelphia. Breintnal. Kahn and Pilgram. St. Petersburg. Kraft. The Delisles. Berlin. Kirch. Pilgram and Phil. Trans. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Berlin. (Kirch. Wittemberg. Weidler. Sweden. Celsius. Frobes and Mairan. Pilgram and Phil. Trans. Pilgram. ; St. Petersburg. Kraft. The Delisles. Berlin. Kirch. Wittemberg. Weidler. ON THE PERIODICITY OF THE AURORA BOREALIS. Sweden. Celsius. Frobes and Mairan. Pilgram and Phil. Trans. Plymouth. Huxham. Wittemberg. Weidler. St. Petersburg. (Kraft. The Delisles. Italy. Beceari. Berlin. Kirch. Sweden. Celsius. Frobes. Mairan, Pilgram, and Phil. Trans. Wittemberg. Weidler. Mairan and Phil. Trans. Sweden. Celsius. Frobes and Mairan. Wittemberg. Weidler. Berlin. Kirch. Sweden. Celsius. Frobes and Mairan. Pilgram and Phil. Trans. Mairan? and Pilgram. Paris. Mairan. Pilgram. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Sweden. Celsius. Frobes and Mairan. Phil. Trans and Mairan. Celsius, Frobes, and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Phil. Trans. and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. . Mairan. Pilgram. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Mairan. Pilgram. St. Petersburg. Kraft. The Delisles. Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Sweden. Celsius. Frobes and Mairan. Plymouth. Huxham. Short. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. 1732. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Sweden. Sweden. Sweden. Celsius.? Celsius. Celsius. Mairan.® Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Wittemberg. Weidler. Mairan. 1 Mém. del’Acad. 1731, p. 385. 2 Acta Lit. Suecie, III. B. 44. 8 Compare pp. 492 and 544, of Traité par Mairan. Jan. 26. 27. 28. 28. 29. 29. 29. 30. 30. =I (oh) Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes. Paris. Mairan. Plymouth. Huxham. Short. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Wittemberg. Weidler. Mairan. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. Plymouth. Huxham. Short. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Frobes and Mairan. Frobes and Mairan. St. Petersburg. The Delisles, Berlin. Kirch. Mairan. Sweden. Celsius. Frobes. Ttaly. Beceari. Mairan. Sweden. Celsius. Frobes and Mairan. St. Petersburg. The Delisles. Mairan. St. Petersburg. The Delisles. Berlin. Kirch. Phil. Trans. Wittemberg. Weidler. Mairan. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. St. Petersburg. The Delisles. Mairan. St. Petersburg. The Delisles. Mairan. St. Petersburg. The Delisles. Mairan. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. Mairan. Frobes and Mairan. The Delisles. Berlin. Kirch. Phil. Trans. Sweden. Celsius. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes. Paris. Mairan. St. Petersburg. The Delisles. Italy. Beccari. Mairan. Sweden. Celsius. Frobes. St. Petersburg. The Delisles. Sweden. Celsius. Frobes and Mairan. . de l’Acad. 1733, p. 478. 38 Mar. 26. 20. ON THE PERIODICITY Paris? Mairan. Frobes. Sweden. Celsius. Frobes and Mairan. St. Petersburg. The Delisles. Berlin. Kirch. Paris? Mairan. Sweden. Celsius. Frobes. St. Petersburg. The Delisles. Sweden. Celsius. Frobes and Mairan. St. Petersburg. The Delisles. Sweden. Celsius. Frobes and Mairan. St. Petersburg. The Delisles. Celsius. Mairan. Sweden. Celsius. Frobes and Mairan. St. Petersburg. The Delisles. Paris. Mairan. St. Petersburg. The Delisles. Mairan. Paris. Mairan. Paris. Mairan. Sweden. Celsius. Frobes. Sweden. Celsius. Paris. Mairan. Frobes Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Sweden. Celsius. Frobes and Mairan. Berlin. YKirch. Mairan and Phil. Trans. Paris. Mairan. Paris. Mairan. Paris. Mairan. Paris. Mairan. Paris. Mairan. Paris. Mairan. Frobes and Mairan. Paris. Mairan. Frobes. Paris. Mairan. Ttaly. Beccari. Mairan. St. Petersburg. The Delisles. Mairan. Meudon. Mairan. Wittemberg. Weidler. Berlin. Kirch. Sweden. Celsius. Phil. Trans. Paris. Mairan. F robes. Celsius, Frobes, and Mairan. St. Petersburg. Kraft. Paris. Du Fay. -Mairan. St. Petersburg. The Delisles. Paris. Buache. Mairan and Thompson. Paris. Mairan. Berlin. Kirch. Breuillepont. Frobes and Phil. Trans. Breuillepont. Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Ttaly. Veratti+ St. Petersburg. The Delisles. Breuillepont. Mairan. Frobes. St. Petersburg. The Delisles. Mairan. 1 Comm. Bonon. II. Pt. III. 493. Sept. 20. “ “ “ OF THE AURORA BOREALIS. Breuillepont. Mairan. Frobes. St. Petersburg. Kraft. Breuillepont. Mairan. Frobes and Mairan. Frobes and Mairan. Frobes and Mairan. St. Petersburg. The Delisles. Paris. Mairan. Frobes. St. Petersburg. The Delisles. Berlin. Kirch. Mairan. St. Petersburg. The Delisles. Mairan. Paris. Mairan. Paris. Mairan. Paris. Mairan. St. Petersburg. The Delisles. Berlin. YKirch. Paris. Mairan Sweden. Celsius. Frobes. Paris. Mairan. St. Petersburg. The Delisles. Mairan. St. Petersburg. The Delisles. Mairan. Paris. Mairan. Paris. Mairan. Frobes. Paris. Mairan. Paris. Mairan. St. Petersburg. The Delisles. Paris. Mairan St. Petersburg. The Delisles. Mairan. Paris. Mairan. Berlin. (Kirch. Paris. Mairan. Sweden. Celsius. Frobes. Wittemberg. Weidler. Paris. Berlin. Yirch. Phil. Trans. Sweden. Celsius. Frobes. Paris. Mairan. St. Petersburg. The Delisles. Paris. Mairan, St. Petersburg. The Delisles. Paris? Mairan. St. Petersburg. The Delisles. Mairan. St. Petersburg. The Delisles. Mairan. St. Petersburg. The Delisles. Paris. Mairan. Mairan. Paris. Mairan. St. Petersburg. Kraft. The Delisles. Puris. Mairan. Sweden. Celsius. Mairan. St. Petersburg. The Delisles. Berlin. Kirch. Frobes and Thompson. Copenhagen. Uorrebow. Mairan. St. Petersburg. The Delisles. Frobes. Mairan. St. Petersburg. Kraft. The Delisles. Mairan. St. Petersburg. The Delisles. Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Italy. Beccari. Frobes and Mairan. St. Petersburg. The Delisles. Mairan. Nov. 22. “ 94, Dec. 7 a 10: So 13: “« 13. = t6: co LS © 19: Jan. 12 IE wake Feb. 13. I «16: Mar. 2. its 8. “ 5. eh - « 22. & 25; Apr. 1. “ i is “ 3: « 133. SPL Gs May 6. a 9: cos tA: < 16: « 16. 18s 205 Gs Oe Gy ans ate Ci PPh. Feb. 6. (73 Hie Gs ANB CcoaGe Cie es Ge NG eco Pilaie « 18. cK 20: «20: Ol « 98. Mar. 1. Gs aly, Gr Bi), 30) Apr. 3. “ 52 41 Plymouth. Wuxham. Mairan and Short. Bloomsburg. Celsius. Mairan, Short, and Phil. Trans. London. Celsius. Mairan and Phil. Trans. St. Petersburg. The Delisles. Mairan. Short. St. Petersburg. The Delisles. Mairan. Lincopie. Sparschuch. Lincopice. Sparsehuch. Wittemberg. Weidler. St. Petersburg. Kraft. Lincopie. Sparschuch. Wittemberg. Weidler. Frobes and Mairan. St. Petersburg. The Delisles. Frobes and Mairan. Frobes and Mairan. St. Petersburg. Kraft. The Delisles. Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Peterborough. Neve Edinburg. Short. Mairan and Phil. Trans. Mairan. The Delisles. Frobes and Mairan. Mairan. 1736. St. Petersburg. Kraft. The Delisles. Mairan. Celsius. Mairan and Phil. Trans. Plymouth. Huxham. Plymouth. Wuxham. St. Petersburg. The Delisles. Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Plymouth. Huxham. Lincopie. Sparschuch*® St. Petersburg. Kraft. The Delisles. Frobes, Mairan, and Phil. Trans. Plymouth. Huxham. Lineopie. Sparschuch. Cambridge, Eng. Celsius. Mairan and Phil. Trans. St. Petersburg. The Delisles. Plymouth. Huxham. tialy. Beccari. Mairan. St Petersburg. The Delisles. Lincopie. Sparschuch, Mairan.* St. Petersburg. Kraft. Mairan. Mairan. The Delisles. 1 Phil. Trans, XL. 53. 2 At Utrecht, 62 auroras were observed in this year. not given. Dates See letter of Musschenbroek to Du Fay. Mém. de VP Acad. 1736, p. 504. 3 Acta Lit. Sueciw, IV. 249. * See his general catalogue, p. 545 of Traité &e. Boué ascribes the observation incorrectly to the Delisles. OF THE PERIODICITY OF THE AURORA BOREALIS. Lincopie. Sparschuch. Apr. 5. Wittemberg. Weidler. Mairan. “ 14. St. Petersburg. The Delisles. “ 14. Lincopie. Sparschuch. London. Celsius. “14, Mairan and Phil. Trans. May 4. Jtaly. Beccari. Mairan. July 7. Jtaly. Beccari. Mairan. « 8. Italy. Beccari. Mairan. Aug.13. St. Petersburg. Kraft. The Delisles. Mairan. « 15. St. Petersburg. The Delisles. Mairan. « 20. St. Petersburg. The Delisles. Mairan. “« 25. Plymouth. TWuxham. “ 29. Plymouth. Wuxham. Sept. 3. Wittemberg. Weidler. Mairan. « 4, Wittemberg. Weidler. Mairan. “ 4, Lincopie. Sparschuch. « 5. St. Petersburg. Kraft. The Delisles. Mairan. “« 5. Plymouth. Huxham. Phil. Trans. “ = 9. Plymouth. WHuxham. “ 13. St. Petersburg. The Delisles. Mairan. “ 17. Upsal. Wallerius.t « 24. Upsal. Wallerius. « 925. Upsal. Wallerius. Phil. Trans. “ 25. Italy. Beccari. Mairan and Short. « 26. St. Petersburg. Kraft. The Delisles. Mairan. | “ 27. Upsal. Wallerius. « 29, Lincopie. Sparschuch. « 29-30. Upsal. Wallerius. « 30. Italy. Beccari. Mairan. Oct. 1. Upsal. Wallerius. J/t. Kittis. Celsius.’ « 2. Mt. Kittis. Celsius. “« 3. Mt. Kittis. Celsius. Upsal. Wallerius. « 4, Mt. Kittis. Celsius. « 5. Upsal. Wallerius. “« 6. Mt. Kittis. Celsius. « 7-8. Upsal. Wallerius. “« 7, Mt. Kittis. Celsius. Mairan. 7. The 8. 8. 10. ie PAVE 22. CA. “ 95 no ce 1 Acta Lit. Suecie, IV. 220. Plymouth. Huxham. Short. Plymouth. WHuxham. Short. Mt. Kittis. Celsius. Mairan. Wittemberg. Weidler. Mairan. Upsal. Wallerius. Frobes and Mairan. Upsal. Wallerius. Lincopic. Sparschuch. Tremblay. Du Fay. Wittemberg. Weidler. Frobes and Mairan. 2 Acta Lit. Suecia, LV. 254. 8 Mém. de l’Acad. 1736, p. 505. Oct. 26. Oe i fp «27. VB: Cie ie <6. 529: 29° co 505 Nov. 7. “ eS: “ 9. ce! 7/8 i ONG: Eg: « 719. 2A: “ D4. 42D: “ x. Dec. 1. “ 3. « 10: cD: <) 8: Salis. “ 19. “< 22. cae Pye 2 Seas “ 95 tos Jan “ 9, 7 AE G ilee Lincopie. Sparschuch. Wittemberg. Weidler. Frobes, Mairan, and Phil. Trans. Upsal. Wallerius. Mt. Kittis. Frobes, Mairan, and Phil. Trans. Mt. Kittis. Celsius. Frobes, Mairan, and Phil. Trans. Frobes and Mairan. Plymouth. Wuxham. Mairan and Short. Mairan and Short. Mairan and Short. St. Petersburg. Kraft. The Delisles. Mairan. Plymouth. Wuxbam. Mairan and Short. St. Petersburg. The Delisles. Plymouth. Wuxham. Short. Plymouth. Huxham. Lineopie. Sparschuch. Edinburg. Short Frobes and Mairan. Celsius. Mairan. Lincopie. Sparschuch. Mairan. St. Petersburg. Kraft. The Delisles. Mairan. Upsal. Wallerius. Mt. Kittis. Celsius. Mt. Kittis. Celsius. Tornea. Celsius. Ofwer-Tornea. Maupertius.* Upsal. Wallerius. Tornea. Celsius. Tornea. Celsius. Thompson. Paris. De Fouchy. Boué. Tornea. Celsius. Tornea. Celsius. Tornea. Celsius. Tornea. Celsius. 1737. Italy. Beceari. Yornea. Celsius. Mairan. Tornea. Celsius. St. Petersburg. The Delisles. Mairan. Tornea. Celsius. Tornea. Celsius. Tornea. Celsius. Tornea. Celsius. Tornea. Celsius. Mairan. Phil. Trans. Salem. Holyoke.® Philadelphia. Breintnal.* Kahn. Tornea. Celsius. Upsal. Wallerius. Tornea. Celsius. 1 Phil. Trans. XLI. Pt. I. 368. 2 Oeuvres, III. 157. 3 Felt’s Salem, II. 137. * Phil. Trans., XLI. Pt. I. 359. “ “ 10. ali le 22. 24. June 3. 30. 20. 21. 21. 21. 22. 22. 23. 23. 23. OF THE PERIODICITY OF THE AURORA BOREALIS. 45 Tornea. Celsius. Tornea. Celsius. ; Upsal. Wallerius. Lincopie. Sparschuch.t Tornea. Celsius. Upsal. Wallerius. Tornea. ftaly. Beccari. Mairan. Upsal. Wallerius. Tornea. Lincopie. Sparschuch. Lincopie. Sparschuch. Tornea. Lineopie. Sparschuch. Tornea. Celsius. Tornea. Celsius. Tornea. Celsius. Kiemi. Celsius. Kiemi. Celsius. Tornea. Celsius. Upsal. Wallerius. Tornea. Celsius. Tornea. Celsius. Tornea. Celsius. Plymouth. Wuxham. Mairan and Short. Mairan, Short, and Phil. Trans. St. Petersburg. Kraft. The Delisles. Mairan.* Celsius. Celsius. Celsius. Wittemberg. Weidler. Mairan. Plymouth. Wuxham. Short. Wittemberg. Weidler. Mairan. Mt. Kittis. Celsius. Mt. Kitiis. Celsius. Mt. Kittis. Celsius. Mt. Kittis. Celsius. Wittemberg. Weidler. St. Petersburg. Kratt. St. Petersburg. Kraft. Tornea. Celsius. St. Petersburg. Kraft. Italy. Beecari. Mairan. Italy. Beceari. Mairan. Plymouth. Huxham. Phil. Trans. Wittemberg. Weidler. Mairan and Short. Italy. Beceari. Plymouth. Huxhem. Short. Wittemberg. Weidler. Mairan and Phil. Trans. Plymouth. Tuxham. Mairan and Short. Philadelphia, &c. Kahn. Phil. Trans. Plymouth. Huxham. Wittemberg. Weidler. St. Petersburg. Kraft. The Delisles. Mairan, Short, and Phil. Trans. Mairan. The Delisles. Mairan. The Delisles. Mairan. The Delisles. Mairan. 1 Acta Lit. Suecix, IV. 437. 2 Comm. Petrop. IX. 359. 3 Penn. Gazette. Aug. 24. tO 2D: ae O153 Sept. 4. ae Fats 5 2: Cn a. oe (- = 128: RS <> 30: Oct a: “ De Soe Deve « 24, 2: 26 Noy. 6. Cale Cee ees 2b: TSO: Dee. 12. Gs «16: c* 3163 «99: 20: aL C22: oo 283 Jan. 25. Feb. 12. me liGs 19: Mar. 8. <8: “< 19. ce Ar Apr. 10. e163 July 11. St. Petersburg. Kraft. The Delisles. Mairan. Italy. Beccari. Mairan. St. Petersburg. Kraft. The Delisles. St. Petersburg. Kraft. The Delisles. Mairan. Mairan and Phil. Trans. St. Petersburg. Kraft. The Delisles. Mairan. Lincopie. Sparschuch. Frobes and Mairan. Lincopie. Sparschuch. Mairan, Short, and Phil. Trans. Lincopie. Sparschuch. Mairan. Phil. Trans. and Short. Mairan, Short, and Phil. Trans. Mairan, Short, and Phil. Trans. Mairan and Phil. Trans. St! Petersburg. Kraft. The Delisles. Mairan. Mairan and Phil. Trans. Mairan and Phil. Trans. Mairan.* Boué. Lincopie. Sparschuch. Lincopie. Sparschuch. Lincopie. Sparschuch. Plymouth. Huxham. Plymouth. Huxham. Wittemberg. Weidler. Mairan and Phil. Trans. Lincopie. Sparschuch. Bologna. Zanotti and Beceari.t Plymouth. Huxham. Wittemberg. Weidler. Frobes, Mairan, Thompson, and Phil. Trans. Montpelier. Plantade. Siberia. Gmelin.? Mairan and Phil. Trans. Italy. Beccari. Italy. Beceari. Italy. Beccari. Mairan. Mairan. Mairan. Frobes and Mairan. 1738. Plymouth. Huxham. St. Petersburg. Kraft? Italy. Beccari. Mairan and Short. Lincopie. Sparschuch. Mairan.* Mairan, Short, and Phil. Trans. Mairan.* Lincopie. Sparschuch. Mairan, Short, and Phil. Trans. Plymouth. Huxham. Ttaly. Beccari. Mairan. Mairan. 1 Comm. Bonon. IT. Pt. I. 476. 2 Comm. Petrop. XI. 252. 8 Ibid. XT. 244. * Mairan gives an aurora on these dates in his general cata- logue (Traité, p. 545), but not in any special one. 28: « 10: “ 15 ST cD: PE Jan. 2. “ 4. Ge Ee eds Son: 30: Feb. z. “ iS “ 9, “ 15 CS Estee NE 27: Mar. 5. “ 6. “ 6. “ he “ 8. ae (05 “« 10. alk a es 1 Mém 256. OF THE PERIODICITY OF THE AURORA BOREALIS. Italy. Beeeari. Mairan. St. Petersburg. Kraft. St. Petersburg. Kraft. St. Petersburg. Kraft. St. Petersburg. Kraft. Lincopie. Sparschuch. Lincopie. Sparschuch. Plymouth. Wuxham. Plymouth. Huxham. Lincopie. Sparschuch. Plymouth. Huxham. Plymouth. Wuxham. Lincopie. Sparschuch. St. Petersburg. (Kraft. Lincopie. Sparschuch. Wittemberg. Weidler. Mairan. St. Petersburg. (Kratt. Lincopie. Sparschuch. Lincopie. Sparschuch. Lincopie. Sparschuch. Lincopie. Sparschuch. Lincopie. Sparschuch. Lincopie. Sparschuch. Lincopie. Sparschuch. 1739. Lincopie. Sparschuch. Lineopie. Sparschuch. Mairan and Short. Frobes and Mairan. Upsal. Celsius. St. Petersburg. (Kraft. Frobes and Mairan. St. Petersburg. Kraft. Upsal. Celsius. Mairan, Short, and Phil. Trans. Frobes and Mairan. Upsal. Celsius. St. Petersburg. Katt. Wittemberg. Weidler. Upsal. Celsius. Upsal. Celsius. Mairan and Phil. Trans. Plymouth. Wuxham. Short. Mairan and Phil. Trans. St. Petersburg. Kraft. Bologna. Zanotti and Beccari. Frobes and Mairan. St. Petersburg. Kraft. Plymouth. Huxham. Upsal. Celsius. . Etrang. Paris, IV. 137. Svenska Vetensk. Acad. I. 2 Comm. Petrop. XI. 255. Frobes and Mairan. Mar. 12. Ly Pd Soaps: Sei sy ae. Zs eT. Cae Oe 5 2 «29; S20. ce OU: Apr. 1. “ 4, “ 5. “ 9, SLO: Ge Tallt) Soe lO: 20% Ea ave May 1 “ Aug. ake J lek ce ii be e238: coa0s Koes Sept. 5. “ 6. “ 7 ie “ S: “ 9, “« 93 O14. Apr. 2. . 2. « 30. June. 7. « 13. = °30. ay A Sept. 8. oy als Oct * 1: « 3. Noy. 10. Dec. 2. “ x. “ x. . Le - x. “ 6. ON THE PERIODICITY OF THE AURORA BOREALIS. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Wittemberg. Weidler. Mairan. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Cambridge. Winthop. Lovering. Upsal. Celsius. St. Petersburg. Kraft. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. 1744. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Wittemburg. Weidler. Mairan. Plymouth. THuxham. Upsal. Celsius. London. Mairan and Phil. Trans. Upsal. Celsius. South America. At Cusco 12° S. Lat. Boué.?| Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Italy. Beceari. Mairan. Upsal. Celsius. Mairan and Phil. Trans. Mairan and Phil. Trans. Mairan and Phil. Trans. Mairan and Phil. Trans. Mairan and Phil. Trans. Tubingen. Kraft. 1 Svenska Vetensk. Acad. VI. 18. 2 Mém. de l’Acad. 1747. p17. 8 N. Comm. Petrop. I. 144. VOL. X. Dee. 25. “ “ 28. 81. 49 Plymouth. Huxham. Upsal. Celsius. Upsal. Celsius. 1745. Upsal. Celsius. Plymouth. Huxham. Wittemberg. Weidler. Mairan. Upsal. Celsius? Upsal. Celsius. Stuttgart. Du Vernoi.? Upsal. Celsius. Upsal. Celsius. Plymouth. Huxham. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Tubingen. Kraft. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Jtaly. Beccari. Mairan. Ttaly. Beecari. Mairan. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. 1746. Tubingen. Kraft. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. Stuttgart. Du Vernoi. Upsal. Celsius. Upsal. Celsius. Tubingen? Kraft. Upsal. Celsius. Upsal. Celsius. Upsal. Celsius. 1 Svenska Vetensk. Acad. VII. 72. 2N. Comm. Petrop. I. 144. 8 Svenska Vetensk. Acad. VIII. 155. Feb. 15 elo. PAO). iG HIle GBP “ 624, 2G: Mar. 5. “ 9, <0: se) =; ce 12; GP ase AS <0: D5 LF PA) Apr. 12. June 12. Go IY co 15. July 4. Aug. 4. Sept.15. ley SPAR 23; 25. 2G: Oct. 12. CD: 20: BPA G3 y apiile as Es C3 PH Jan. 4. Stuttgart. Upsal. Upsal. Upsal. Upsal. Upsal. Cambridge. Stuttgart. Stuttgart. Tubingen. Steinebrunn. Stuttgart. Gottingen. Tubingen. Upsal. Upsal. Upsal. Upsal. Gottingen. Cambridge. Gottingen. Plymouth. Upsal. Upsal. Upsal. Upsal. Upsal. Upsal. Upsal. Steinebrunn. Upsal. Italy. Steinebrunn. Cambridge. Steinebrunn. Cambridge. Upsal. Upsal. Upsal. Upsal. Cambridge. Near Philadelphia. Upsal. Upsal. Wittemberg. Weidler. Stuttgart. Beccari. Ferner. Ferner. Ferner. Ferner. Ferner. Winthrop. Volzius. Volzius. Kraft. Bischoff. Volzius. Hollmann. Kraft. Ferner. Ferner. Ferner. Ferner. Hollmann. Winthrop. Hollmann. Huxham. Ferner. Ferner. Ferner. Ferner. Ferner. Ferner. Ferner. Bischoff. Ferner.t Lovering. Lovering. Mairan. Bischoff. Winthrop. Lovering. Bischoff.” Winthrop. Lovering. Ferner. Plymouth. Huxham. Ferner. Ferner. Ferner. Winthrop. Lovering. Kalm. Ferner. Ferner. Mairan. Volzius. 1749. Volzius. 1 Auroras were seen at Upsal on two other days in October. 2 Auroras were seen at Upsal six times in November. 52 ON THE PERIODICITY OF THE AURORA BOREALIS. Jan. 31. Stuttgart. Volzius. Feb. 1. Stuttgart. Volzius. “9. Upsal. Ferner. “10. Upsal. Ferner. “ 11. Upsal. Ferner. “ 13. Stuttgart. Volzius. “ 15. Near Philadelphia. Kalm. “ 16. Cambridge. Winthrop. Lovering. «“ 23. Upsal. Ferner. “ 27. Stuttgart. Volzius. Mar. 9. Cambridge. Winthrop. Lovering. “9. Upsal. Ferner. “ 10. Upsal. Ferner. “ 11. Upsal. Ferner. Wargentin.? «12. ‘Upsat. Werner. | * “ 13. Upsal. Ferner. “ 18. Upsal. Ferner. «20. Upsal. Ferner. “ 21. Upsal. Ferner. Stuttgart. Volzius. “ 21. Steinebrunn. Bischoff. “ 22. Upsal. Ferner. “ 23. Upsal. Ferner. “ 28. Stuttgart. Volzius. “ 29. Stuttgart. Volzius. Apr. 1. Stuttgart. Volzius. « 3. Stuttgart. Volzius. « 5. Upsal. Ferner. “ 5. Cambridge. Winthrop. Lovering. “ . ~Upsal. Ferner. “ 10. Gottingen. Hollmann. “ 11. Stuttgart. Volzius. “ 12. Gottingen. Hollmann. “ 13. Upsal. Wargentin. “ 18. Upsal. Ferner. Stuttgart. Volzius. “ 18. Cambridge. Winthrop. Lovering. “ 20. Stuttgart. Volzius. “ 25. Stuttgart. Volzius. “ 27. Stuttgart. Volzius. May 10. Gottingen. Hollmann. “ 11. Cambridge. Winthrop. Lovering. “ 14? Stuttgart. Volzius. June 7. Cambridge. Winthrop. Lovering. July 21. Canada. Kal. Aug.16. QOpsal. Ferner. Sept. 4. Upsal. Ferner. « 5. Upsal. Ferner. «7. ~Upsgl. Ferner. 1 Svenska Vetensk. Acad. XIII. 215. 2 Acad. Coil. Etrang. Dijon. XI. 191. Svenska Vetensk. Acad. XI. 57. Sept.13. Cambridge. Winthrop. Lovering. “ 17. Italy. Beccari. Mairan. « 22. Italy. Beccari. Mairan. “ 22. Leipsic. Heinsio1 Gottingen. Hollmann. Oct. 3. Tubingen. Kraft. Steinebrunn. Bischoff. «8. Upsal. Ferner. Jtaly. Beccari. Mairan. “ 10. Upsal. Ferner. “11. Upsal. Ferner. “ 18. Cambridge. Winthrop. Lovering. “ 18. Upsal. Ferner. “27. Upsal. Ferner. Noy. 6. Cambridge. Winthrop. Lovering. «6. Upsal. Ferner. “ 9. Cambridge. Winthrop. Lovering. “ 28. Upsal. Ferner. Dec. 7. Upsal. Ferner. «12. Upsal. Ferner. “ 17. Upsal. Ferner. 1750. Upsal. Ferner. Upsal. Ferner. Cambridge. Winthrop. Lovering. Cambridge. Winthrop. Lovering. Wittemberg. Weidler. Mairan. Tooting. Miles. Baker. Reuss. Leipsic. Heinsio. Upsal. Ferner.® Ttaly. Beccari. Mairan. Wittemberg. Weidler. Thompson. Chelsea. Martyn.A Paris. Fouchi.' Cambridge. Winthrop. Lovering. Wittemberg. Weidler. Mairan. Gottingen. Hollman. Italy. Beccari. Mairan. Upsal. Ferner. « 10. Upsal. Ferner. Gottingen. Hollmann. “ 14. Tubingen. Kraft.6 Steinebrunn. Bischoff. “ 26. Upsal. Ferner. Plymouth. Uuxham. “« 26. Mairan, Reuss, and Phil. Trans. “ 27. Upsal. Ferner. Thompson. “ 27. Cambridge. Winthrop. Lovering. “ 27. Wittemberg. Weidler. Mairan. Reuss. atte al Al a np SO Fe Con co! coe 1 N. Comm. Petrop. IV. 477. 2 Phil. Trans. XLVI. 346 & 399, where it is accidentally put down for Jan. 25, 1751, though the communication bears an earlier date. 8 Svenska Vetensk. Acad. XTV. 255. * Phil. Trans. XLVI. 319. 5 Encyc. Method. I. 353. ® N. Comm. Petrop. V. 403. “ 7. Mar. 4. “ 4, “ 7 “ 9, J 1h [ Salle eee 4. “ 15 Apr. 3. “ 8. “ a “ 9, “ 9, 4, “« 14, “ 30. aii): « 30. May 1. “ oe 6 19, July 26. “. 96. 6 28% Aug.10. «16: sae 1743 “ 24, “ 24. “26. & 26. « 26. « DF. i929. Sept. 4. “ 6. i Ppp en) Dae Oct. 12. «20: Noy. 2. “ 4, “ Ds ON THE PERIODICITY OF THE AURORA BOREALIS. Philadelphia. Kalm. Chelsea. Martyn Plymouth. Huxham. The Hague. Gabry.’ Cambridge. Winthrop. Lovyering. Upsal. Ferner. Gottingen. Hollmann. Upsal. Ferner. Upsal. Ferner. Cambridge. Winthrop. Lovering. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Steinebrunn. Bischoff. Ttaly. Beccari. Mairan.® Cambridge. Winthrop. Lovering. Upsal. Ferner. Cambridge. Winthrop. Lovering. Upsal. Ferner. Cambridge. Winthrop. Lovering. Philadelphia. Kahn. Cambridge. Winthop. Lovering. Philadelphia. Kalm. Stockholm. Ekeberg.* South Carolina, U. 8. Cambridge. Winthrop. Lovering. Wittemberg. Weidler. Mairan. Tubingen. Kraft. Steinebrunn. Bischoff. Cambridge. Winthrop. Lovering. Leipsie. Heinsio. Cambridge. Winthrop. Lovering. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Gottingen. Hollmann. Wittemberg. Weidler. Mairan. Cambridge. Winthrop. Lovering. Bologna. Zanotti and Beccari. Mairan. Reyger. Boué.® Reuss. Italy. Beccari. Mairan. Upsal. Ferner. Cambridge. Winthrop. Lovering. Tubingen. Kraft. Upsal. Ferner. Letpsic. Heinsio. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Cambridge. Winthrop. Lovering. Cambridge. Winthrop. Loyering. Upsal. Ferner. Gottingen. Hollmann. 1 Phil. Trans. XLVI. 345. 2 Phil. Trans. XLVII. 39. 3 In his general catalogue, it is April 13. Traité &c. p. 546. * Acad. Coll. Etrang. Dijon. XI. 191. © Gent. Mag. XX. 428. 6 Nat. Gesell. Danzig. Abh. III. 258, Nov. 6. 20: Dec. 14. cc 195 a PSs Sailr Jan. 8. hits Feb. 11 es Sale). CLs CRs Cay pyle Mar. 17 Apr. 2. “ A. June 10. PN Aug. 19 Sept. 14. ec 22: « 26. fe ile «30: Oct. 22. BE « 27. abe “ 80. Noy. Dec “ “ 9, CLO! Gs atile Si aS 5 ETO: “ 25) Jan. 9. 53 Upsal. Ferner. Tubingen. Kraft. Italy. Beccari. Mairan. Gottingen. Wollmann. Gottingen. Hollmann. Upsal. Ferner. 1751. Steinebrunn. Bischoff. Tubingen. Kraft. Gottingen. Hollmann. Cambridge. Winthrop. Lovering. Wittemberg. Weidler. Mairan. Cambridge. Winthrop. Lovering. Steinebrunn. Bischoff. Cambridge. Winthrop. Lovering. Upsal. Ferner? Cambridge. Winthrop. Lovering. Upsal. Ferner. Tubingen. Kraft. Cambridge. Winthrop. Lovering. Italy. Beccari. Mairan. Tubingen. Kraft. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Tubingen. Kraft. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Thompson.° Steinebrunn. Bischofl. Tubingen. Kraft. 1752. Upsal. Ferner. 1 N. Comm. Petrop. V. 405. 2 Syenska Vetensk. Acad. XV. 175. 8 Annals of Phil. 1814. IV. 427. ON THE PERIODICITY OF THE AURORA BOREALIS. Jan. 13. Upsal. Ferner.’ “15. Upsal. Ferner. “ 16. Upsal. Ferner. “ 19. Cambridge. Winthrop. Lovering. “ 19. Upsal. Ferner. « 920, Upsal. Ferner. « 21. Upsal. Ferner. ‘© 22. Upsal. Ferner. « 29, Steinebrunn. Bischoff. Feb. 10. Upsal. Ferner. “ 12. Upsal. Ferner. “ 16. Upsal. Ferner. “ 17. Upsal. Ferner. “ 18. Upsal. Ferner. Mar. 4. Upsal. Ferner. “: 7. Upsal. Ferner. « 8. Upsal. Ferner. Tubingen. Kraft. “ 8. Gottingen. WHollmann. “ 10. Upsal. Ferner. “ 11. Upsal. Ferner. Fubingen. _ Kraft. “12. Upsal. Ferner. “ 13. Upsal. Ferner. “ 16. Upsal. Ferner. « 17. Upsal. Ferner. Tubingen. Kraft. “ 18. Upsal. Ferner. « 27. Upsal. Ferner. May 17. Steinebrunn. Bischoff. “ 24, Tubingen. Kraft. « 98. Stattgart. Volzius.? July 27. Tubingen. Kraft. Aug. 1. Tubingen. Kraft. “ 11. Tubingen. Kraft. “ = 12. Tubingen. Kraft. “ 13. Tubingen. Kraft. « 15. Stuttgart. Volzius. Steinebrunn. Bischoff. Sept. 3. Tubingen. Kraft. “8. Upsal. Ferner. “ 27. Upsal. Ferner. Oct. 2. Upsal. Ferner. « 3. Upsal. Ferner. Gottingen. Hollman. & 5. Upsal. Ferner. “ 6. Gottingen. Hollmann. se 7. Upsal. Ferner. Gottingen. Hollmann. “12. Upsal. Ferner. “ 12. Cambridge. Winthrop. Lovering. “ 13. Gottingen. Hollmann. “ 14. Upsal. Ferner. 1 Svenska Vetensk. Acad. XVI. 290. 2 N. Comm. Petrop. V. 410. Oct. 24. Nov. 2. “ B. “« 10. BA hi ls « 28. Dec. 4. “ 5. “ 6. “ “ 95 Feb. 23. 26: Gy ete Mar.) “ AE “ 9, ae i kil 12; KO OD: Apr. 2. “ 3. « 10: as alate “ 1 2} “14. «< 20. « 30. is B10) Aug. 17. 23s Sept. 1. “ 2 “ 3. 1D: « 929. « 30. Nov. 25. Stuttgart. Volzius. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Tubingen. Kraft. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Tubingen. Kraft. 1753. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner? Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Gottingen. Hollmann. Upsal. Ferner. Cambridge. Winthrop. Lovering. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Gottingen. Hollmann. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. Upsal. Ferner. 1 Svenska Vetensk. Acad. XVI. 290. 2 The Gregorian Calendar was adopted in Sweden in 1753, the 17th of February being followed by the Ist of March. Therefore the dates commencing with March Ist are published here as given by Ferner. All the previous dates were reduced from OLD STYLE to new style. ON THE PERIODICITY OF THE AURORA BOREALIS. Dec. 15. Upsal. Ferner. “16. Upsal. Ferner. “ 18. Upsal. Ferner. « 27. Upsal. Ferner. “28. Upsal. Ferner. 1754. Jan. 12. Upsal. Ferner.” Feb. 8 Upsal. Ferner. “ 24. Upsal. Ferner. Mar.17. Upsal. Ferner. « 18. Upsal. Ferner. “20. Upsal. Ferner. “ 25. Upsal. Ferner. “ 26. Upsal. Ferner. Apr. 9. Upsal. Ferner. “10. Upsal. Ferner. Sept.23. Upsal. Ferner. Oct. 9. Upsal. Ferner. « 16. Upsal. Ferner. “27. The Hague. Gabry? Noy. 15. Upsal. Ferner. “ 16. Upsal. Ferner. « 17. Opsal. Ferner. Dec. 31. Upsal. Ferner. 1755. Jan. 30. At Sea, near Norway. Ekeberg.* Feb. 3. Upsal. Ferner.® « 5. Upsal. Ferner. “ 8. St. Petersburg. Braun®. Sept. 9. Upsal. Ferner. Oct. 5. Upsal. Ferner. “ 24, Upsal. Ferner. “ 30. Upsal. Ferner. Nov. 1. Upsal. Ferner. “28. Upsal. Ferner. “Dec. 31. Upsal. Ferner.7 1756.8 Feb. 18. Upsal. Ferner.? “ 19. Upsal. Ferner. Reuss and Boué. Reuss. 1 An aurora was seen at Constantinople in 1754. Phil. Trans. XLIX. 119. 2 Svenska Vetensk. Acad. XVI. 290. 8 Mém. de l’Acad. Sav. Etrang. III. 581. # Svenska Vetensk. Acad. XVIII. 61. 5 Svenska Vetensk. Acad. X VIII. 208. 6 N. Comm. Petrop. VII. 405. 7 Aurora Australis. 8 Once in Upsal in January. ® Svenska Vetensk. Acad. XTX. 231. Mar.28. Upsal. Ferner. Apr. 2. Upsal. Ferner. © 11. Upsal. “Werner: Sept. 1. Upsal. Ferner. “14. Upsal. Ferner. “ 15. Upsal. Ferner. - 22. St. Petersburg. Braun. “ 28. Upsal. Ferner. « 29. Upsal. Ferner. « 30. Upsal. Ferner. Oct. 20. Upsal. Ferner. “20; Upsal. Eerner. « 26. Upsal. Ferner. 1757. Jan. 5. St. Petersburg. Braun. Mar. 31. Rouen Bouin. Boué. Reuss. Aug.13. Cambridge. Winthrop. Lovering. Sept. 7. Cambridge. Winthrop. Lovering. “ 13. Cambridge. Winthrop. Lovering. “ 14. Cambridge. Winthrop. Lovering. “ 16. The Hague. Gabry. Boué.? Reuss. Noy. 12. Cambridge. Winthrop. Lovering. “ 12. Philadelphia. Bartram. Reuss. “ 13. Cambridge. Winthrop. Lovering. “ 18. London. Franklin. 1758. Jan. 8. Cambridge. Winthrop. Lovering. Mar.12. Cambridge. Winthrop. Lovering. “« 26. St. Petersburg. Braun.4 “ 31. Cambridge. Winthrop. Lovering. Apr. 1. Cambridge. Winthrop. Lovering. May 19. Spitzbergen. Martin.® June 2. Spitzbergen. Martin. “ 26. Spitebergen. Martin. “ 27. Spitzbergen. Martin. “ 28. Spitzbergen. Martin. 1759. Feb. 3. Upsal. Bergman.® « 4, Upsal. Bergman. Thompson. “4, Hernosand. Gisler. Boué. “« 15. Upsal. Bergman. Thompson. “ 15. Hernosand. Gisler. Boué. 1 Mém. de l’Acad. Sav. Etrang. IV. 242. 2 Mem. de l’Acad. Sav. Etrang. LV. 597. 3 Phil. Trans. LII. 474. * N. Comm. Petrop. IX. 418. 5 Svenska Vetensk. Acad. XIX. 315, 55 5 Nova Acta Sci. Upsal. I. 418 and Phil. Trans. LII. 479. 56 ON THE PERIODICITY OF THE AURORA BOREALIS. Feb. 18. Upsal. Bergman. “« 19. Upsal. Bergman. “ 20. Upsal. Bergman. Rouen. Bouin.’ Reuss. | Mar. 8. Cambridge. Winthrop. Lovering. “ 17. Upsal. Bergman. | “ 18. Upsal. Bergman. St. Petersburg. Braun.?| «“ 22. Upsal. Bergman. | “ 28. Upsal. Bergman. Apr. 5. Upsal. Bergman. “ 16. Upsal or Stockholm. Bergman. “ 22. St. Petersburg. Braun. Aug.16. Upsal. Bergman. “« 26. Upsal. Bergman. “ 27. Upsal. Bergman. “ 28. Upsal. Bergman. « 29. Upsal. Bergman.® Sept. 9. Cambridge. Winthrop. Lovering. « 10. Upsal. Bergman. “ 11. Upsal. Bergman. “ 11. Cambridge. Winthrop. Lovering. “ 12. Upsal. Bergman. “ 15. Upsal. Bergman. “ 16. Upsal. Bergman. Rouen. Bouin. Reuss.* “ 16. North Germany. Hartmann. Boué.® “ 18. Cambridge. Winthrop. Lovering. “ 19. Upsal. Bergman. « 20. Upsal. Bergman. “ 21. Upsal. Bergman. “ 22. Upsal. Bergman. «“ 23. Upsal. Bergman. « 24. Upsal. Bergman. Oct. 18. Upsal. Bergman. “ 15. Upsal. Bergman.® “ 31. St. Petersburg. Braun. “ 31. Cambridge. Winthrop. Lovering. Noy. 5. Upsal. Bergman. « 9. Upsal. Bergman. “ 15. Upsal. Bergman. “ 16. Upsal. Bergman. « 20. Upsal. Bergman. “ 21. Upsal. Bergman. «“ 22. Upsal. Bergman. « 27. Upsal. Bergman. “« 28. Upsal. Bergman.’ 1 Mem. de l’Acad. Say. Etrang. V. 103. 2 N. Comm. Petrop. X. 367. 8 This is in Phil. Trans. but not in Nova Acta Sci. Upsal. 4 Mém. de l’Acad. Say. Etrang. VI. 253. 5 Hamb. Mag. XXIV. 157. 6 This is in Phil. Trans. but not in Nova Acta Sci. Upsal. 7 This is in Nova Acta Sci. Upsal, but not in Phil. Trans. | Dec. 9. <0: “Fahl | * 12. eA: era: So: | « 16. Us" vilefs 19: eee 3 GE Jan. 10. “ 1 2 Sh ode “<8: “ 23; Feb. 8. Se Sati sc 12: oe ait 2S ils paths F « 620; Sih ile pp Mar. 5. “ 6. Cie i>: ey le « 16. “« 28. Apr. 2. “ 3. “ 6. “ 8: “ 9. Kc 0; « 1. 2. <4. SS eG: AG: 17. o sil7e Oct. 26. Berlin. Beguelin. Berlin. Beguelin. St. Petersburg. Euler2 Berlin. Beguelin. Berlin. Beguelin. St. Petersburg. Euler. St. Petersburg. Euler. Cambridge. Winthrop. Newport, R. I. Stiles. St. Petersburg. Euler. St. Petersburg. Euler. Berlin. Beguelin. Berlin. Beguelin. Cambridge. Winthrop. Newport, R. I. Stiles. St. Petersburg. Euler. Berlin. Beguelin. St. Petersburg. Euler. Jena. Zeissing. St. Petersburg. Euler. St. Petersburg. Euler. Berlin. Beguelin. St. Petersburg. Euler. Berlin. Beguelin. Cambridge. Winthrop. Berlin. Beguelin. Berlin. Beguelin. Cambridge. Winthrop. Berlin. Beguelin. Cambridge. Winthrop. Cambridge. Winthrop. Cambridge. Winthrop. Cambridge. Winthrop. Liibeck. Behn. Boué.? Jena. Zeissing. Jena. Zeissing. Cambridge. Winthrop. Lovering. Cambridge. Winthrop. Lovering. Jena. Zeissing. Beziers. Bertholon. Gottingen. Boué.* Cambridge. Winthrop. Lovering. Berlin. Beguelin. Cambridge. Winthrop. Lovering. Montmorenci. Cotte. Berlin. Beguelin. Lovering. Loomis. Lovering. Loomis. Berlin. Beguelin. Berlin. Beguelin. Berlin. Beguelin. Lovering. Lovering. Lovering. Lovering. Lovering. Lovering. Pekin. Amiot.* St. Petersburg. Euler. 1 N. Comm. Petrop. XV. 682. 2 Sitz. Bericht. Wien. XLV. 442. 8 Hannov. Mag. 1770, p.1217. * Kamtz. Lehrbuch der Met. III. 465. Liibeck. Behn. Boué. OF THE PERIODICITY OF Nov. 8. Liibeck. Behn. Boué.t « 24. St. Petersburg. Euler. “ 26. Liibeck. Behn. St. Petersburg. Euler. Dec. 17. Jena. Zeissing. “ 24. Jena. Zeissing. IGFAl Jan. 6. Berlin. Beguelin. “ 15. Berlin. Beguelin. “ 18. Berlin. Beguelin. “ 20. Berlin. Beguelin. “« 26. St. Petersburg. Euler.? Feb. 7. St. Petersburg. Euler. s 8. St. Petersburg. Euler. “ 9. Berlin. Beguelin. “ 10. Berlin. Beguelin. « 15. Berlin. Beguelin. “ 19. Cambridge. Winthrop. Lovering. « 19. Berlin. Beguelin. St. Petersburg. Euler. “19. Montmorenci. Paris. Franeker. Cotte.* « 20. Montmorenci. Cotte. Mar. 2. St. Petersburg. Euler. “ 13. St. Petersburg. Euler. Berlin. Beguelin. 183. Montmorenci. Franeker. Cotte. “ 14. St. Petersburg. Euler. “ 15. St. Petersburg. Euler. “ 16. St. Petersburg. Euler. “ 17. Cambridge. Winthrop. Lovering. “ 17. St. Petersburg. Euler. « 18. Cambridge. Winthrop. Lovering. «23. St. Petersburg. Euler. « 30. Paris. Boué. Apr. 2. SS. Petersburg. Euler. «4, Berlin. Beguelin. «5. Berlin. Beguelin. Montmorenct. Cotte. “ 15. Berlin. Beguelin. Montmorenci. Cotte. May 2. Berlin. Beguelin. “3. Berlin. Beguelin. “ 6? Berlin. Beguelin. Y 7. Berlin. Beguelin. . < 8. Berlin. Beguelin. “ 12. St. Petersburg. Euler. “ 12. Franeker. Cotte. Jena. Zeissing. “ 13. St. Petersburg. Euler. Franeker. Cotte. June 2. Cambridge. Winthrop. Lovering. “« 2. Liibeck. Behn. Boué. 1 In the Chateau de Saintes en Hainaut, three auroras were ob- served in 1770. Mém. de |’Acad. Brux. I. 554. 2 N. Comm. Petrop. XVI. 695. 8 Mém. de Met. I. THE July “ AURORA BOREALIS. June 12. 2: 12 os 12; 16. NG. 30. 61 Cambridge. Winthrop. St. Petersburg. Euler. Berlin. Beguelin. Berlin. Beguelin. St. Petersburg. Euler. Cambridge. Winthrop. Cambridge. Winthrop. Franeker. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. Cambridge. Winthrop. Cambridge. Winthrop. St. Petersburg. Euler. St. Petersburg. Euler. Cambridge. Winthrop. Franeker. Cotte. Berlin. Beguelin. St. Petersburg. Euler. St. Petersburg. Euler. Berlin. Beguelin. Franeker. Cotte. Cambridge. Winthrop. Lovering. St. Petersburg. Euler. St. Petersburg. Euler. Cambridge. Winthrop. Franeker. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. Cambridge. Winthrop. Cambridge. Winthrop. Berlin. Beguelin. Franeker. Cotte. Berlin, Beguelin. Cambridge. Winthrop. Franeker. Cotte. St. Petersburg. Euler. Lovering. Lovering. Lovering. Lovering. Lovering. Lovering. Berlin. Beguelin. Lovering. Lovering. Lovering. Lovering. 1772. Berlin. Beguelin. Berlin. Beguelin. Bradford, Mass. Williams. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler.? Bradford, Mass. Williams. Berlin. Beguelin. Franeker. Cotte. St. Petersburg. Euler. Marseilles. Cotte. St. Petersburg. Euler. 1 Amer. Phil. Soc. II. 118. 2 N. Comm. Petrop. XVII. 717, 2 OF THE PERIODICITY OF THE AURORA BOREALIS. Feb. 27. Cambridge. Winthrop. Lovering. Oct. 16. Franeker. Cotte. 27. Bradford, Mass. Williams. “« 20. Franeker. Cotte. Mar. 2. Franeker. Cotte. “ 23. Marseilles. Cotte. £ 8. Franeker. Cotte. «“ 27. Montmorenct and Marseilles. Cotte. 2% 5. Berlin. Beguelin. “ 27. Jena. Zeissing. % 6. DMontmorenci. Cotte. «27. Piedmont. Berando. Pilgram.) 10. St. Petersburg. Euler. “« 29. Franeker. Cotte. 11. - St. Petersburg. Euler. « 30. Franeker. Cotte. 13. St. Petersburg. Euler. Nov. 7. St. Petersburg. Euler. 16. St. Petersburg. Euler. « 24. Berlin. Beguelin. 17. St. Petersburg. Euler. “« 26. St. Petersburg. Euler. 19. St. Petersburg. Euler. “ 27. Berlin. Beguelin. 21. St. Petersburg. Euler. Dec. 2. St. Petersburg. Euler. 22. Berlin. Beguelin. “ 14. Bradford, Mass. Williams. 28. Berlin. Beguelin. Franeker. Cotte. “ 18. Berlin. Beguelin. 30. Berlin. Beguelin. “« 29. St. Petersburg. Euler. Apr. 3. Berlin. Beguelen. Franeker. Cotte. id 4. St. Petersburg. Euler. 1773. 12. Cambridge. Winthrop. Lovering. Jan. 4. St. Petersburg. Euler. 12. Bradford, Mass. Williams. “ 17. Cambridge. Winthrop. Lovering. « 14. St. Petersburg. Euler. “ 17. Newport, R. I. Stiles. Loomis. 15. St. Petersburg. Euler. “ 17, Berlin. Beguelin. 20. - Berlin. Beguelin. “ 18. Berlin. Beguelin. Franeker. Cotte. 22. St. Petersburg. Euler. “ 18. Newport, R. L Stiles. Loomis. “ 25. Berlin. Beguelin. “ 19. Cambridge. Winthrop. Lovering. “ 29. Franeker. Cotte. “ 19. Newport, R. I. Stiles. Loomis. June 14. Marseilles. Cotte. “ 19, Berlin. Beguelin. « 21. Franeker. Cotte. “ 21, Berlin. Beguelin. July 5. Cambridge. Winthrop. Lovering. “ 26. St. Petersburg. Euler. us 5. Bradford, Mass. Williams. “ 97, St. Petersburg. Euler. c 7. Cambridge. Winthrop. Lovering. “ 98. St. Petersburg. Euler. 4 8. Cambridge. Winthrop. Lovering. “ 29. St. Petersburg. Euler. € 8. Bradford, Mass. Williams. Feb. 7. St. Petersburg. Euler. : ge 8. Newport, R. J. Stiles. Loomis. “« 8. St. Petersburg. Euler. 25. Cambridge. Winthrop. Lovering. “ 10. St. Petersburg. Euler. « 25. Bradford, Mass. Williams. “12. St. Petersburg. Euler. « 25. Newport, R. I. Stiles. Loomis. 17. South Gatiade? Aug. 31. Berlin. Beguelin. Montmorenct. Cotte. | « 18, Fyaneker. Van Swinden. Sept. 4. Stockholm. Wilke. “ 18. Berlin. Beguelin2 « 20. Berlin. Beguelin. “ 20. Franeker. Van Swinden. 25. Franeker. Cotte. “ 20. Berlin. Beguelin. ‘ 27. Franeker. Cotte. Stockholm. Wilke. “ 91. Franeker. Wan Swinden. Oct. Cambridge. Winthrop. Lovering. “ 21. Berlin. Beguelin. : Bradford, Mass. Williams. « 92. Berlin. Beguelin. Montmorenci. Brussels. Franeker. Cotte.’ Mar. 4. St. Petersburg. Euler. St. Petersburg. Euler. Marseilles. Cotte.} « 12. Franeker. Cotte. Berlin. Beguelin. Brussels. Cotte. St. Petersburg. Euler. “ 43. Franeker. Cotte. Marseilles. Cotte. n 2 Dan eats et 1 Encye. Method. I. 348. Journ. de Say. 1773, p. 188. 1 Gilbert. Ann. XXIX. 420. 2 Kamtz. Lehrbuch der Met. III. 465. Mar.14. Berlin. Beguelin. “ 15. Cambridge. Winthrop. Lovering. “ 16. Franeker. Van Swinden. “ 21. Berlin. Beguelin, “ 23. Cambridge. Winthrop. Lovering. “ 23. St. Petersburg. Euler. Franeker. Cotte. “ 24, St. Petersburg. Euler. “ 26. Berlin. Beguelin. Liibeck. Behn. Boué. “ 26. Montmorenci and Franeker. Cotte. “ 27. St. Petersburg. Euler. April 1. St. Petersburg. Euler. “ 17. Franeker. Cotte. “ 20. Brussels. Cotte. “ 23. St. Petersburg. Euler. “ 27. Franeker. Cotte. “« 29. St. Petersburg. Euler. May 4. St. Petersburg. Euler. “ 5. St. Petersburg. Euler. “« 8. St. Petersburg. Euler. “ 11. Marseilles. Cotte. “ 13. Berlin. Beguelin. “ 17. Berlin. Beguelin. “ 18. Berlin. Beguelin. “ 19. Cambridge. Winthrop. Lovering. “ 19. Berlin. Beguelin. “ 23. Ltibeck. Behn. Boué. “ 24, Marseilles. Cotte. “ 26. Marseilles. Cotte. June 6. Cambridge. Winthrop. Lovering. « 6. Newport, R. I. Stiles. Loomis. “ 10. Cambridge. Winthrop. Lovering. “ 13. Cambridge. Winthrop. Lovyering. “ 14. Cambridge. Winthrop. Lovering. “ 17. Cambridge. Winthrop. Lovering. “ 24. Cambridge. Winthrop. Lovering. “ 24. Franeker. Cotte. July 12. Cambridge. Winthrop. Lovering. “ 17. Cambridge. Winthrop. Lovering. “ 17. Newport, R. I. Stiles. Loomis. “ 17. Bradford, Mass. Williams. Spain. Rico. “ 17. Franeker. Cotte. Reuss.? Paris. Wallot. “ 18. Cambridge. Winthrop. Lovering. “ 25. Cambridge. Winthrop. Lovering. “ 25 .Francker. Cotte. Aug.15. Cambridge. Winthrop. Lovering. “ 15. Breslau. Reuss.* “ 16. Breslau. Reuss. 1 Amer. Phil. Trans. II. 136. OF THE PERIODICITY OF THE AURORA BOREALIS. 2 Mem. de l’Acad. 1773, p. 6. 8 Repert. Comment. IV. 131. Aug.25. << 261 Sept. 1. U3 ald). “ 12 CSD: Ce lee Sa IE «22. 2A: ONG Oct. 7. “ 8. ce 2s « 16; Gale C20: 20: Cle HEE AS Be): role Nov. 1. “ Ff “ Ss cas Un ly Gay <2 Gs ag Dil C28: <0 4293 Dec. 13. Ga “ 15 “ 95 Jan. 9. CeO! Ge pale OPP Feb. 14. | Osi. Mar. 2. “ 3. “ se Cambridge. Winthrop. Lovering. St. Petersburg. Euler. Marseilles. Cotte. Montmorenci and Franeker. Franeker. Cotte. Berlin. Beguelin. Paris. Cotte. Pekin. St. Petersburg. Euler. Marseilles. Cotte. Marseilles. Cotte. Franeker. Cotte. Franeker. Cotte. St. Petersburg. Euler. Franeker. Cotte. Stockholm. Wilke. Franeker and Brussels. St. Petersburg. Euler. Cotte. Amyot. Cotte. Boué. 63 Monimorenci, Franeker, and Brussels. Cotte. Franeker. Cotte. Franeker. Cotte. Franeker. Cotte. Marseilles. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. Berlin. Beguelin. Berlin. Beguelin. Berlin. Beguelin. Franeker. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. Franeker. Cotte. St. Petersburg. Euler. Franeker and Marseilles. Cotte. St. Petersburg. Euler. — 1774, Newport, R. I. Stiles. Loomis. Franeker. Cotte. Franeker. Cotte. St. Petersburg. Euler.+ St. Petersburg. Euler. St. Petersburg. Euler. Cambridge. Winthrop. Lovering. Franeker. Cotte. Berlin. Newport, R. f. Stiles. Loomis. Beguelin. Franeker, Montmorenci, and Brussels. Cotte. 1 N. Comm. Petrop. XIX. 653. “ “ “ “ 30. June 4. OF THE PERIODICITY OF THE AURORA BOREALIS. Berlin. Beguelin. Cambridge. Winthrop. Lovering. Newport, R. I. Stiles. Loomis. Franeker. Cotte. Berlin. Beguelen. Franeker, Montmorenci and Brussels. Cotte. Newport, R. I. Stiles. Loomis. Franeker and Montmorenci. Cotte. Berlin. Beguelin. Franeker. Cotte. Franeker. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. Franeker. Cotte. St. Petersburg. Euler. Berlin. Beguelin. Berlin. Beguelin. Franeker. St. Petersburg. Euler. Berlin. Beguelin. St. Petersburg. Euler. Cambridge. Winthrop. Lovering. Berlin. Beguelin. Franeker. Cotte. Berlin. Beguelin. St. Petersburg. Euler. Franeker. Cotte. Berlin. Beguelin. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. Brussels. Cotte. St. Petersburg. Euler. Marseilles. Cotte. Marseilles. Cotte. Franeker and Brussels. | Cotte. St. Petersburg. Euler. Franeker and Marseilles. Stockholm. Wilke. Franeker. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. Cologne. Bildersael. Brussels. Cotte. St. Petersburg. Euler. Franeker. Cotte. Franeker. Cotte. Cambridge. Winthrop. Lovering. Liibeck. Behn. Boué. Liibeck. Behn. Boué. Liibeck. Behn. Boué. Cotte. Pilgram. Cotte. | Stockholm. Wilke. June 13. ccemlya July 9. «10: GIP Kai 13: als: eee. 20: oF PASE SO: Aug. 2. “ 3. C4: Le Oil 22s K 23: & (24. « 26. CPX C2: eee Sept. 1. cs “ 8. “ 9. fib ce 9: Ale 22. “ D4. « 25 12.6: LH) <3 S10: Oct. 1. “ 5. “ 6. “ 5. “ ae Bi I Gh als = WBE 2 VIG) mo le 0s SPAS CEE Marseilles. Cotte. Liibeck. Behn. Boué. Cambridge. Winthrop. Lovering. Marseilles. Cotte. Cambridge. Winthrop. Lovering. Cambridge. Winthrop. Lovering. Franeker. Van Swinden. Franeker. Van Swinden. Cotte.t Franeker. Van Swinden. Cotte. Cambridge. Winthrop. Lovering. Cambridge. Winthrop. Lovering. Franeker. Cotte. Franeker. Cotte. Cambridge. Winthrop. Lovering. Franeker. Cotte. Liibeck. Behn. Franeker and Marseilles. St. Petersburg. Euler. Marseilles. Cambridge. Marseilles. Marseilles. Franeker. Cotte. Cambridge. Winthrop. St. Petersburg. Euler. Franeker. Cotte. St. Petersburg. Euler. Cambridge. Winthrop. Franeker. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. Marseilles. Cotte. Marseilles. Cotte. St. Petersburg. Euler. Marseilles. Cotte. Berlin. Beguelin. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. Newport, R. Stiles. St. Petersburg. Euler. Berlin. Beguelin. St. Petersburg. Euler. St. Petersburg. Euler. Winthrop. Cotte. Cotte. Lovering. Loomis. Franeker. Cotte. St. Petersburg. Euler. Franeker. Cotte. St. Petersburg. Euler. Franeker. 1 Mém. de l’Acad. Say. Etrang. Paris. VIII. 394. Cotte. St. Petersburg. Lovering. Lovering. Boué. Euler. Cotte. * ON THE PERIODICITY OF THE AURORA BOREALIS. 65 Oct. 20. St. Petersburg. Euler. Mar.21. Franeker. Cotte. “ 28. St. Petersburg. Euler. “ 22. St. Petersburg. Euler. Nov. 3. Cambridge. Winthrop. Lovering. “24. St. Petersburg. Euler. “ 3. Franeker. Cotte. St. Petersburg. Euler. | “ 25. Cambridge. Winthrop. Lovering. « 5. Cambridge. Winthrop. Lovering. “ 26. Franeker. Cotte. “ 5. Franeker. Cotte. St. Petersburg. Euler. | “ 27. Franeker. Cotte. “« 7. St. Petersburg. Euler. “ 28. Franeker. Cotte. “11. Franeker. Cotte. “ 29. Franeker. Cotte. “ 24. St. Petersburg. Euler. “ 30. Franeker. Cotte. St. Petersburg. Euler. “« 26. St. Petersburg. Euler. |Apr. 1. St. Petersburg. Euler. Dec. 1. Franeker. Cotte. St. Petersburg. Euler. | “ 2. St. Petersburg. Euler. “ 1. Newport, R. I. Stiles. Loomis. « 4, Franeker. Cotte. « 4, Marseilles. Cotte. “ 13. Franeker. Cotte. “ 26. St. Petersburg. Euler. “ 15. Franeker. Cotte. «“ 28. St. Petersburg. Euler. “ 17. Franeker. Cotte. “ 18. Franeker. Cotte. 1775. “ 19. Franeker. Cotte. “ 20. Franeker. Cotte. Jan. 1. St. Petersburg. Euler.? « 23. St. Petersburg. Euler. “ is, £ 56. 5 aa a Franeker. Cotte. gor get edhe “ 21. Montmorencit and Franeker. Cotte Ra cite ey a cs 91. St. Petersburg. Euler. pe li 4 yee : v, ae St ia Euler. July 18. Cambridge. Winthrop. Lovering. = 23. raicber ea Sie Peterson Euler nye ee ee is ae ees. Cotte, P g- *| © 21. Franeker. Cotte. ce 95. Transker. Cotte. St. Petersburg. Eul ER Sea ‘ aa as Po 5 a ‘ g- tuuler. | « 927, St. Petersburg. ° Euler. _ 97, St. os wee ao fe Sept.15. Franeker. Cotte. es 28. Gan, a oe Feanaber Cotte a Ae aay a 59. Cities” Wastin Lorering 5 CaN. Montmorenci and Franeker. Cotte. & 29. Newport. R IE Stiles, Deane” Roel baa ho oe & 29, St. eis Mpler: 4c ae ee ae “ 23. Franeker. Cotte. i 5 . “« 24, St. Petersburg. Euler. Ae “= Pee, Cale h : “27. Franeker. Cotte. St. Petersburg. Euler. EN esha! peeops yp Levene: Oct. 138. St. Petersburg. Euler. « 4, Brussels. Cotte. e ““ 19. Franeker. Cotte. St. Petersburg. Euler oe rps a ey 3: 20, Bev deaae Cotte St rel Eul gp Se ei ei ; a re or ung. MUET- | Nov. 23. Franeker. Cotte. Be as ag Ona eeemaae Dec. 15. Franeker. Cotte. Berlin. Beguelin. “ 21. Franeker. Cotte. St. Petersburg. Euler. r “ 23. St. Petersburg. Euler. 1776 “ 28. Franeker. Cotte. : Mar.19. Franeker. Cotte. Jan.18. Berlin. Beguelin. “ 20. Franeker. Cotte. “ 18. St. Petersburg. Euler. “ 20. Franeker. Cotte. 1 All the St. Petersburg observations from Jan, 17,1772 to| « 91, Franeker. Cotte. Berlin. Beguelin. the bottom of page 64 should be corrected by subtracting 11 ikl, Saari (ORie. days from their respective dates: the error having originated in reducing to new style dates already corrected. 2 N. Comm. Petrop. XX. 643. VGOln x 9 1 Acta Sci. Acad. Petrop. 1777, Pt. 1, p. 384. ¢ Holland. Cotte. Montmorenci and Franeker. St. Petersburg. Euler. St. Petersburg. Euler. Holland. Cotte. Montmorenci and Holland. Cotte. St. Petersburg. Euler. Holland. Cotte. Berlin. Beguelin. Paris. Cotte. Jena. Zeissing. Detienne and Pingré. Reuss. Montmorencit and Franeker. Cotte. Amsterdam. Cotte. Cotte. Beguelin. St. Petersburg. Euler. Dighton, Mass. Stiles. Loomis. Montmorenci. Cotte. St. Petersburg. Euler. Franeker, Brussels, and Holland. Cotte. St. Petersburg. Euler. Montmorenci. Berlin. Franeker. Van Swinden. Cotte. St. Petersburg. Euler. Franeker. Van Swinden. Cotte. Franeker and Amsterdam. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. Franeker. Van Swinden. Amsterdam. Cotte. St. Petersburg. Euler. Berlin. Beguelin. Cambridge. Winthrop. Lovering. Franeker and Holland. Cotte. Berlin. Beguelen. Holland. Cotte. Brussels. Cotte. St. Petersburg. Euler. Berlin. Beguelin. Franeker. Van Swinden. Holland and Brussels. Cotte. St. Petersburg Euler. Berlin. Beguelin. Franeker. Van Swinden. St. Petersburg. Euler. Holland and Brussels. © Cotte. Cambridge. Winthrop. Lovering. Montmorenci. Cotte. St. Petersburg. Euler. Franeker. Van Swinden. Holland and Brussels. Cotte. Franeker. Van Swinden. St. Petersburg. Euler. Holland and Brussels. Cotte. Franeker. Van Swinden. Berlin. Beguelin. Franeker. Cotte. 66 ON THE PERIODICITY OF THE AURORA BOREALIS. Mar.. 9. St. Petersburg. Euler. Jan. 30. “ 18. Montmorenci. Cotte. Feb. 5. “ . 93. Franeker. Cotte. 2 5. “ 28. Montmorenci. Cotte. c 6. “« 928. St. Petersburg. Euler. £ 6. Apr. 8. Montmorenci, Franeker, and Brussels. Cotte.| “ ite “« 10. Brussels. Cotte. CLO: “ 18. Cambridge. Winthrop. Lovering. ty etic “ 19. Franeker. Cotte. S526: May 3. Brussels. Cotte. I ONS “ 21. Franeker. Cotte. fa G: “ 23. Brussels. Cotte. <> 26: “« 25. Brussels. Cotte. is June 6. Brussels. Cotte. Mar. 1. es 7. Brussels. Cotte. se 5. July 7. Franeker. Cotte. ee 5. Aug. 14. Montmorenci and Franeker. Cotte. £ 5. Sept. 3. St. Petersburg. Euler. se 6. se 4. Cambridge. Winthrop. Lovering. oe 9. ‘% 4. Franeker. Cotte. Os Ke 5. Cambridge. Winthrop. Lovering. Cae & 5. Franeker and Montmorenct. Cotte. ts 3 5. Berlin. Beguelin. St. Petersburg. Euler.| “ 12. &“ 6. Franeker. Cotte. ie G 8. St. Petersburg. Euler. STA. “3 9. St. Petersburg. Euler. 6 22, “ 12. Franeker. Cotte. S28; “ 16. Cambridge. Winthrop. Lovering. ce 28. “ 16. Montmorenci, Brussels,and Franeker. Cotte.| “ 29. “ 16. St. Petersburg. Euler. Bordeaux. Cotte.| “ 29. “« 19. St. Petersburg. Euler. “F) 2BE “ 22. Montmorenci and Brussels. Cotte. ee ail. “ 23. Franeker. Cotte. St. Petersburg. Euler.| Apr. 1. “ 24. Franeker. Cotte. se 4 «“ 25. Brussels. Cotte. KS 4 Oct. - 3. Franeker. Cotte. se 4 “ 6. St. Petersburg. Euler. c. a 7. St. Petersburg. Euler. SEM ther “ 27. Franeker. Cotte. ce 5 Nov. 16. Franeker. Cotte. Berlin. Beguelin. = 6. Dec. 16. Franeker. Cotte. Co 6. “ 7 1777. “« 7 . = 8 Jan. 13. Montmorenci. Cotte. a 3 “28. Cambridge. Winthrop. Lovering. a 8 « 28. Dighton, Mass. Stiles. Loomis. -: 9 “ 28. Franeker and Holland. Cotte. Feb. 1 9. “« 28. St. Petersburg. Euler. tS 1 Acta Sci. Acad. Petrop. 1777, Pt. 2, p. 395. 1 Journ . de Phys. IX. 272 and 275. Apr. 9. “ 9. «1. Ee 7 May 4. “ 5. SPS 8 PHI « 30. its 3 June 28. w= PASE July 27. baler af ( Aug. 6. “17. & 94. Se cediz ae & 30: Sept. 5. “ 6. “ 7. “ he “ ve “ 15 eA. 94 (24. « 24. Ts = 28. «30. Oct. 3. “ 3: ees. ge (5 “13; ee 22: 4. a: “ 95 Noy. 3. “ 8. SE “ 3. “ 3. ON THE PERIODICITY OF THE AURORA BOREALIS. 67 Holland and Brussels. Cotte. St. Petersburg. Euler. Cambridge. Winthrop. Lovering. St. Petersburg. Euler. Holland. Cotte. Franeker, Holland, Amsterdam, &c. Cotte. Spain. Larrea. Rico. Lewarden. Cotte. Franeker. Van Swinden. Cotte. Franeker. Van Swinden. Cotte. Cambridge. Winthrop. Lovering. Franeker. Cotte. Cambridge. Winthrop. Lovering. Portsmouth, N. H. Stiles. Loomis. Franeker. Cotte. Berlin. Beguelin. Franeker and Breda. Cotte. Montmorenci and Holland. Cotte. Franeker, Montmorenci, and Holland. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. St. Petersburg. Euler. Cambridge. Winthrop. Lovering. Paris. Detienne. Boué.t Franeker and Montmorenci. Cotte. St. Petersburg. Euler. Cambridge. Winthrop. Lovering. Portsmouth, N. H. Stiles. Loomis. Berlin. Beguelin. St. Petersburg. Euler. Franeker, Montmorenci, and Holland. Cotte. Perpignan. Cotte. Franeker. Cotte. St. Petersburg. Euler. Geneva. Deluc.? Cambridge. Winthrop. Lovering. Franeker. Van Swinden. Cotte. Franeker. Van Swinden. Cotte. Spain. Larrea. Rico. Franeker and Holland. Cotte. Montmorenci. Cotte. Franeker. Yan Swinden. Franeker. Van Swinden. Cotte. Cambridge. Winthrop. Lovering. Berlin. Beguelin. Jena. Zeissing. Franeker, Montmorenci, and Austria. Cotte. Vienna. Pilgram. Paris. Messier. Reuss.* Berlin. Beguelin. Jena. Zeissing. 1 Journ. de Phys. X. 231-3. 2 Bull. de l’Acad. Brux. 1842. Pt. 2. p. 6. 8 Mém. de l’Acad. 1770, p. 440. 3. Vienna. Pilgram. S 6. Holland. Cotte. 7. Franeker and Holland. Cotte. 2 9. Holland. Cotte. “ 21. Franeker and Holland. Cotte. “ 23. Holland. Cotte. “27. Cambridge. Winthrop. Lovering. « 27. Portsmouth, N. H. Stiles. Loomis. « 27. Jena. Zeissing. St. Petersburg. Euler. Reuss. “27. Franeker, Montmorenci, Holland, &c. Cotte. “ 27. Virginia. Madison.? : “ 28. Cambridge. Winthrop. Lovering. Holland. Cotte. Cambridge. Winthrop. Lovering. Portsmouth, N. H. Stiles. Loomis. Holland. Cotte. Berlin. Beguelin. Jena. Zeissing. Franeker, Montmorenci, &c. Cotte. Vienna. Pilgram. Beziers. Bertholon. Berlin. Schulze. Reuss.’ Vienna. Pilgram. Gurzelen. Spriingli. Wolf.4 Berlin. Beguelin. Vienna. Pilgram. Franeker, Montmorenci, and Holland. Cotte Holland. Cotte. Franeker and Holland, Cotte. a me PWS & wm go Go Go go go PO NO PO “ 21. Cambridge. Winthrop. Lovering. “ 27. Mannheim. Pilgram. “« 30. St. Petersburg. Euler. “ 31. Chinon. Cotte. 1778. Jan. 18. Cambridge. Winthrop. Lovering. “ 18. Franeker. Van Swinden.® “18. Copenhagen. Cotte. St. Petersburg. Euler.’ “« 19. Portsmouth, N. H. Stiles. Loomis. “ 19. Holland. Cotte. St. Petersburg. Euler. “« 20. Franeker. Van Swinden. Holland. Cotte. “« 20. St. Petersburg. Euler. “ 21. Franeker. Van Swinden. “ 21. Montmorenct and Holland. Cotte. « 921. St. Petersburg. Euler. 1 Acta Sci. Acad. Petrop. 1777, Hist. Pt. II. p. 71. 2 Amer. Phil. Trans. II. 123. 3 Mém. de l’Acad. Berlin. 1777, p. 106. # Mitt. Naturforsch. Gesell. Bern. 1855, p. 43. 5 Mém. de l’Acad. Brux. III. 449. & Acta Sci. Acad. Petrop. 1778, Pt. II. p. 358. ON THE PERIODICITY OF THE AURORA BOREALIS. Jan. 25. Vienna. Pilgram. |Apr. 21. Breda and Holland. Cotte. « 26. Franeker. Van Swinden. Holland. Cotte. “ 21. St. Petersburg. Euler. “ 27. Holland. Cotte. “ 23. Cambridge. Winthrop. - Lovering. Feb. 1. St. Petersburg. Euler. “23. Provence. Cotte. St. Petersburg. Euler. “ 15. Cambridge. Winthrop. Loyvering. | © 25. Isle d’Oleron. Cotte. “ 16. Chinon. Cotte. “ 26. Cambridge. Winthrop. Lovering. “ 17. Cambridge. Winthrop. Lovering. “« 26. Berlin. Beguelin. “ 17. Portsmouth, N. H. Stiles. Loomis. May 13. Cambridge. Winthrop. Lovering. “ 17. Chinon. Cotte. St. Petersburg. Euler. | “ 14. Franeker. Van Swinden. “ 18. St. Petersburg. Euler. | “ 14. Holland. Cotte. « 25. Jena. Zeissing. Havre. Dicquemare.’ Junel0. Franeker. Van Swinden. Cotte. “ @5. Montmorenci, Sc. Cotte. “ 11. Franeker. Van Swinden. Cotte. “ 25. Vienna. Pilgram. Franeker. Van Swinden. “ 14. Cambridge. Winthrop. Lovering. “ 25. St. Petersburg. Euler. |“ 26. Havre. Dicquemare. « 26. Holland, c. Cotte. “ 28. Cambridge. Winthrop. Lovering. « 28. St. Malo. Cotte. “ 28. Sinigaglia. De Toschi de Fagnaro.* Mar.10. Perpignan. Cotte. | “ 28. Franeker. Van Swinden. - Reuss. “ 15. Gurzelen. Spriingli. Wolf. “ 28. Montmorenci and Cadiz, &c.._ Cotte. “« 16. St. Petersburg. Euler. “ 28. Spain. Rico. “ 17. Cambridge. Winthrop. Lovering. July 3. Perpignan. Cotte. ‘ ome lve ziers. Bertholon. Havre. Diquemare.2 “ 7. Cambridge. Winthrop. Lovering. “ 17. Franeker and Holland. Van Swinden. “ 15. Franeker. Van Swinden. Cotte. “ 17. Montmorenci. Cotte. St. Petersburg. Euler.. “ 31. Cambridge. Winthrop. _Lovering. «“ 18. Montmorenci. Cotte. St. Petersburg. Euler. Aug.12. Franeker. Wan Swinden. “ 19. Holland. Cotte. te 22. Franeker and Holland. Cotte. « 22. Cambridge. Winthrop. Lovering. | “ 28. Breda. Cotte. Berlin. Beguelin. « 22. Berlin. Beguelin. “ 28. St. Petersburg. Euler. «“ 92, Franeker. Van Swinden. Sept. 1. St. Petersburg. Euler. « 22. Holland. Cotte. St. Petersburg. Euler. « 3. St. Petersburg. Euler. “ 24. Cambridge. Winthrop. Lovering. “ 11. Spain. Rico. « 25. Berlin. Beguelin. “ 12. St. Petersburg. Euler. “ 26. Franeker. Wan Swinden. “ 15. St. Petersburg. Euler. « 26. St. Petersburg. Euler. “ 15. Franeker. Wan Swinden. “ 26. Montmorenci and Holland, &c. Cotte. “ 17. Franeker. Van Swinden. “ 27. Franeker. Van Swinden. “ 17. Montmorenci. Cotte. St. Petersburg. Euler. “ 27. Holland. Cotte. “ 18. Copenhagen.and Holland. Cotte. “« 31. Berlin. Beguelin.* “ 18. Berlin. Beguelin. Apr.10. St. Petersburg. Euler. “ 19. Viviers. Cotte. “ 10. Copenhagen. Cotte. “ 20. Mur-de-Barez. Cotte. “ 14. Jena. Zeissing. “ 21. Franeker. Van Swinden. « 15. St. Petersburg. Euler. “ 21. Montmorenci, Holland, &c. Cotte. ' “ 17. Berlin. Beguelin. “ 21. Jena. Zeissing. St. Petersburg. Euler. “ 19, Berlin. Beguelin. « 22. Cambridge. Winthrop. Lovering. “« 20. Cambridge. Winthrop. Lovering. “ 22. New Haven. Stiles. Loomis. “ 22. Montmorenci, Bordeaux, &c. Cotte. SE ees RS « 22. Louvain. Chevalier.* St. Petersburg. Euler. 2 Journ. de Phys. XI. 420. “ 22. Jena. Zeissing. Bildersael. Pilgram. 8 Dicquemare saw auroras at Havre on the last days of* March and on the first ten days of April, 1778. Encyc. Method I. 347. 1 Journ. de Phys. X. 232. Mém. del’Acad. Berlin, 1779. p. 14- 2 Mém. de |’Acad. Brox. III. p. xxvi. Sept.23. sey 24. eas cna. eae Ley F «” 30. «30: Oct. 9. “4; “« 14, 14, «615. OS LDR ce Obs > 926; Sy C Noy. 20. cag: Dec. 3. “ 6. “ ae “ 8. “« 10. “7 alse % 74. Beals Sy hk ale Ce Are Jan. 6. “ 9, « 10. seraey Jan. 13. “4, GUS Feb. 4. ON THE PERIODICITY OF THE AURORA BOREALIS. 69 Copenhagen and Dijon. Cotte. Cambridge. Winthrop. Lovering. New Haven. Stiles. Loomis. Dijon, &e. Cotte. New Haven. Stiles. Loomis. , Holland. Cotte. St. Petersburg. Euler. Berlin. Beguelin. Holland. Cotte. Franeker. Van Swinden. Berlin. Beguelin. Montmorenci, Holland, &c. Cotte. Louvain. Chevalier. Holland. Cotte. Holland. Cotte. Franeker. Van Swinden. Cotte. Spain. Rico. Holland. Cotte. Holland. Cotte. St. Petersburg. Euler. Holland. Cotte. Bertholon.? St. Petersburg. Euler. Alland. Cotte. Franeker. Van Swinden. Cotte. St. Petersburg. Euler. Jena. Zeissing. St. Petersburg. Euler. Troies. Cotte. Holland. Cotte. Franeker. Van Swinden.’ Cotte. St. Petersburg. Euler. Montmorenci. Cotte. 1779. Brussels. Durondean.* Franeker. Cotte. ‘ Holland and Brussels. Cotte. Holland. Cotte. Franeker. Cotte. Saint Saturnin. Cotte. St. Petersburg. Euler.’ Franeker. Cotte. 1 Mem. Acad. Cienc. Madrid. ITI. 77. 2 Journ. de Phys. XI. 269. and XII. 359. 8 Van Swinden suspected auroras on Apr. 27, May 19, 26, and 28, June 12 and 14, Sept. 12 and 18, and Oct. 13 and 17, of this same year. There were twenty-three auroras at Brussels in this year. Mém. de l’Acad. Brux. III. Table. * Mem. de l’Acad. Brux. III. Appendix. 5 Acta. Sci. Acad. Petrop. 1779, Pt. IL. p. 414. Franeker and Holland. | Cotte. | 6. | « 7. St. Petersburg. Euler. 9 Holland, &c. Cotte. Brussels. Durondeau. | « 9. Spain. Rico. “ 10. Cambridge. Winthrop. Lovering. “ 10. Bordeaux. Cotte. Spain, Rico. “ 10. Berlin. Beguelin. Jena. Zeissing. “ 10. St. Petersburg. Euler. “ 11. Cambridge. Winthrop. Lovering. “ 11. Montmorenci, Holland, Sc. Cotte. “ 11. St. Petersburg. Euler. “ 11. Gurzelen, Spriingli. Wolf. “ 12. Franeker, Holland, &c. Cotte. “ 12. St. Petersburg. Euler. “ 13. Cambridge. Winthrop. Loyering. “ 13. Berlin. Beguelin. Beziers. Bertholon. “ 13. Holland, &c. Cotte. St. Petersburg. Euler. “ 13. Gurzelen. Spriingli. Wolf. “ 13. Jena. Zeissing. Vienna. Pilgram. “ 14. Marseilles, &c. Cotte. Jena. Zeissing. “ 15. Montmorenci. Cotte. St. Petersburg. Euler. “ 15. Jena. Zeissing. Spain. Rico. “ 15. Franeker and Copenhagen. Cotte. « 15. Berlin. Beguelin. Beziers. Bertholon. “ 16. Berlin. Beguelin. “ 18. Nanci. Cotte. “ 19. Dieppe. Cotte. “ 25. St. Petersburg. Euler. Mar. 2. Franeker. Cotte. «5. St. Petersburg. Euler. “ 13. St. Petersburg. Euler. « 14, St. Petersburg. Euler. « 14. Nanci, &e. Cotte. Vienna. Pilgram. “ 14. Spain. Rico? Gurzelen. Spriingli. Wolf. “ 15. St. Petersburg. Euler. “ 24. Franeker and Brussels. Cotte. “25. Montmorenci. Cotte. “ 25. Franeker, Holland, &c. Cotte. “ 25. St. Petersburg. Euler. “ 25. Jena. Zeissing. Brussels. Durondeau. “ 30. Copenhagen and Montmorenci.. Cotte. “ 31. Copenhagen. Cotte. Apr. 2. Nanci. Cotte. « 4. Franeker. Cotte. 5. Cambridge. Winthrop... Lovering. “ 7. Montmorenci. Cotte. 8. Brussels. Cotte. St. Petersburg. Euler. 1 Mem. Acad. Cienc. Madrid. III. 77. 2 Mem. Acad. Cienc. Madrid. III. 77. AURORA BOREALIS. Nanci. Cotte. Copenhagen. Cotte. St. Petersburg. St. Petersburg. Euler. Holland. Cotte. Franeker and Copenhagen. Holland. Cotte. St. Petersburg. Euler. Copenhagen. Cotte. St. Petersburg. Euler. Brussels. Cotte. Berlin. Beguelin. Jena. Montmorenci. Cotte. Gurzlen. Spriingli. Berlin. Beguelin. Jena. Zeissing.’ Beziers. Bertholon. Mezin. Cotte. Jena. Zeissing. Strasbourg. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. Franeker and Copenhagen. St. Petersburg. Euler. Nanci. Cotte. St. Petersburg. Euler. Montmorencit and Holland. Cotte. St. Petersburg. Euler. Franeker. Cotte. Copenhagen. Cotte. Brussels. Durondeau. St. Petersburg. Euler. Montmorenci. Cotte. Franeker and Holland, &c. Brussels. Durondeau. Franeker and Copenhagen. Cotte. Brussels. Durondeau. St. Petersburg. Euler. Perpignan. Cotte. Holland. Cotte. St. Petersburg. Euler. St. Petersburg. Euler. Euler. Cotte. Zeissing. Wolf. Marseilles, sc. Cotte. Cotte. Cotte. Saint Saturnin. Cotte. Isle @ Oleron. Cotte. Franeker, Holland, &c. Cotte. Montmorenci. Cotte. Spain. Rico.’ Brussels. Durondeau. Vienna. Pilgram. Berlin. Beguelin. Beziers. Bertholon. Lucon. Cotte. Holland, &c. Cotte. Brussels. Durondeau. Montmorenci and Livourne. Cotte. Berlin. Beguelin. Holland. Cotte. 1 The aurora was observed four times at Jena in October. ON THE PERIODICITY OF THE Franeker and Brussels. Cotte. Aug. 30. St. Petersburg. Euler. Sept. 2. Nanci. Cotte. Berlin. Beguelin. “ Ae Les Essarts. Cotte. « 8. Viviers. Cotte. St. Petersburg. Euler. «70: St. Petersburg. Euler. ae (ah St. Petersburg. Euler. ce ae Franeker. Cotte. Brussels. Durondeau. | « 14, Franeker and Holland. Cotte. ae Sis Copenhagen and Rome, &c. Cotte. a Wy fs St. Petersburg. Euler. ms ae: Brussels. Durondeau. Beziers. Bertholon.| « 18, Nanci. Cotte. « 418. Brussels. Cotte. « 48. Brussels. Cotte. “ 18, Berlin. Beguelin. “« 19, Berlin. Beguelin. “ 992. Berlin. Beguelin. “ 4, Berlin. Beguelin. « 98, Berlin. Beguelin. (St. Petersburg. Euler.) « 28, Montmorenci. Cotte. Berlin. Beguelin. | « 99, Berlin. Beguelin. Ock 3: Berlin. Beguelin. “ 3. Berlin. Beguelin. « ik Berlin. Beguelin. “ 9. Brussels. Cotte. co 1D Copenhagen. Cotte. De i Montmorenci. Cotte. Brussels. Durondeau.}| « 14, Franeker, Holland, &c. Cotte. mnie Brussels. Durondeau. Cees Lie Brussels. Cotte. ce a'72 Brussels. Cotte. 7a ly Isle @ Oleron. Cotte. FI aICY Isle d Oleron. Cotte. ic 1998 Montmorenci. Cotte. « 98. Isle d’ Oleron. Cotte. Nov. 3. Brussels. Durondeau. Bordeaux. Cotte. | « 7? Brussels. Durondeau. Bordeaux. Cotte. | « 8. Brussels. Cotte. « 9. Bordeaux. Cotte. « 9. Franeker and Nanci. Cotte. “« 9. Leyden. Cotte. “« 9. St. Petersburg. Euler. Ge IDs Rouen. Cotte. “« 492. Franeker. Cotte. “« +43. Brussels and Copenhagen. Cotte. By Ve Copenhagen. Cotte. Be Franeker. Cotte. Franeker, Holland, &e. Cotte. Montmorenct. Cotte. 2 Mem. Acad. Cienc. Madrid. III. 77. Noy. 18. Ceo. SLM MOM MUag ON THE PERIODICITY OF THE AURORA BOREALIS. Nanci. Cotte. St. Petersburg. Euler. Gurzelen. Spriingli. Wolf. St. Petersburg. Euler. Brussels. Durondeau. Vienna. Pilgram. Montmorenci. Cotte. Franeker and Holland. Cotte. Montmorenci. Cotte. Franeker and Holland. Cotte. Brussels. Durondeau. “ Franeker. Cotte. & . Jena. Zeissing. St. Petersburg. Kuler. CB) al Brussels. Durondeau. 1780. Feb. 5. St. Petersburg. Schroter and Euler.? “ 11. Franeker and Holland. Cotte. “ 15. St. Petersburg. Schréter and Euler. “22. Montmorenct. Cotte. “ 29. 5 St. Petersburg. Schréter and Euler. “ 29. All over Europe. Cotte. Spain. Rico.? “ 29. Jena. Zeissing: Beziers. Bertholon. “ 29. Turin® Morozzo. Vienna. Pilgram. “ 29. Padua. Toaldo. Reuss.* “29. Gurzelen. Spriingli. Wolf. “ 29. Geneva. Deluc.® Berne. Studer. “« 29. Turin. Morozzo.® Boué. Mar. 1. Perpignan. Cotte. “« 2. Pleskow. De Brekling.’” Reuss. Boué. &“ 2. New Haven. Stiles. Loomis. “« 2. St. Petersburg. Schréter, and Euler. “ 29. Montmorenci. Cotte. “« 30. New Haven. Stiles. Loomis. “ 30. Chinon. Cotte. “ 31. Chinon. Cotte. Apr. 4. Berlin. Beguelin. Us 6. Jena. Zeissing. “ 13. St. Petersburg. Schréter and Euler. May 8. D’Orbessan. Reuss and Boué.® Junel5. Montmorenct. Cotte. “ 23. New Haven. Stiles. Loomis. 1 Acta Sci. Acad. Petrop. 1780, p. 396. 2 Mem. Acad. Cienc. Madrid. III. 77. 8 Mém. de l’Acad. Toulouse. IT. 20. * Saggi Acad. di Padua. I. 78. 5 Mitt. Naturforsch. Gesell. Bern. 1855, p. 44. 68 Mém. de l’Acad. Turin. IT. 328. 7 Acta Sci. Acad. Petrop. 1780, p. 15. 8 Mém. de l’Acad. Toulouse. IT. 26. June 24, July 9. ay ta Cie re} 2G: GDh Cy OR. C28: BSS Xt). cs PH), Aug. 2. ON Sept. 2. “cc 3. “ 4, “ ff co 103 Ga all oh 228 G2, Pile Oct. 4. 3 6. « 10. «24. 28: <30! Bil Nov. 2. “ 4. 14. 19. “201 “ 20. © D1. COR, G28 O23: 2b: D5: sc" 125. e116; 71 New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. Geneva? Delue.’ Frankfort. Pilgram. Germany. Boeckman.? Spain. Rico. Jena. Zeissing. Reuss and Cotte. Italy. Volta. Bildersael. Pilgram. Gurzelen. Spriingli. Wolf. Berne. Studer. New Haven. Stiles. Loomis. Europe. Cotte. New Haven. Stiles. Loomis. St. Petersburg. Schréter and Euler. St. Petersburg. Schréter and Euler. St. Petersburg. Schroter and Euler. St. Petersburg. Schréter and Euler. St. Petersburg. Schréter and Euler. St. Petersburg. Schréter and Euler. St. Petersburg. Schréter and Euler. New Haven. Stiles. Loomis. Franeker and Montmorenci. Cotte. St. Petersburg. Schréter and Euler. Franeker and Montmorenci. Cotte. St. Petersburg. Schréter and Euler. Jena. Zeissing. Barbadoes. Blane. Boué.* St. Petersburg. Schréter and Euler. St. Petersburg. Schréter and Euler. New Haven. Stiles. Loomis. Francker, Geneva, &c. Cotte. New Haven. Stiles. Loomis Berlin. Cotte. Jena. Zeissing. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. St. Petersburg. Schroter and Euler. Franeker. Cotte. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. St. Petersburg. Schréter and Euler. New Haven. Stiles. Loomis. Gurzelen. Spriingli. Wolf. Berne. Studer. Franeker, La Rochelle, &c. Cotte. St. Petersburg. Euler. 1 Bull. de l’Acad. Brux. IX. Pt. II. 6, 2 Mém. de l’Acad. Berlin. 1780, p. 17. 3 Phil. Trans. LX XII. Pt. I. p. xv, 4 Roy. Soc. Edin. I. 34, Nov. “ 25. 26. 26. 27. 28. 29. . Los 19.” 19. 19. 25. 27. 30. 31. 20. 15. 15. 15. 15. 15. 15. 16. Feb. 21. Mar. 14. ON THE PERIODICITY OF THE AURORA BOREALIS. Vienna. Pilgram. Geneva. Deluc.* La Rochelle. Cotte. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. Berlin. Beguelin. St. Petersburg. Schréter and Euler. St. Petersburg. Schroter and Euler. New Haven. Stiles. Loomis. Trieste. Pilgram. Trieste. Pilgram. 1781. Trieste. Pilgram. Ipswich, Mass. Cutler.’ New Haven. Stiles. Loomis. St. Petersburg. Euler.® New Haven. Stiles. Loomis. Abbatias S. Zenonis.* St. Petersburg. Euler. St. Petersburg. Euler. Ipswich. Cutler. Mannheim. Hemmer. Pilgram. New Haven. Stiles. Loomis. Ipswich. Cutler. Munich. Tuebpauer. Padua. Toaldo. Ratisbon. Ueinrich. Vienna. Pilgram. Sagan. Preuss. Beziers. LDertholon. Montmorenct. Cotte.® Ipswich. Cutler. Peissenberg. Fischer and Schlégel. Mannheim. Hemmer. Montmorenct. Cotte. Ipswich, Mass. Cutler. New Haven. Stiles. Loomis. Beziers. Bertholon. Berlin. Mannheim. Hemmer. Ratisbon. Heinrich. Padua. Toaldo. Montmorencet. Mannheim. Hemmer. St. Petersburg. Euler. St. Petersburg. Euler. Beguelin. Cotte. Pilgram. 1 L’Institut. X. 341. 2 Mem. Amer. Acad. I. 337. 8 Acta Sci. Acad. Petrop. 1781. Pt. II. 409. * Observer unknown. Ephem. Soc. Met. Palat. I. 404. 5 Journ. des Savans. 1782, p. 163. Mar. 14. AS Galt 116: Gye icy 55205 « 20: CIDR Os sae Bois 6 Ds PE DI ie SORE 2s PPE C288 OO 28: “283 28. « 1283 “ 520% eo: 29: a DS) BIE Apr. 4. «RTS: Seals “ 14. “« 14, “« 15. “« 15. Die 222 yt 22s LE P25. a5: etic Mar. 6. “ ve ¢-S10! ct Ci les ce 165 <> 16; 20: “120! <2 520: <*20: S27): Ca Al son Pals =~ Pile CONTA 6 Ds De G21. Stil CPA Ce) EEE 83 Gothaab. Ginge. Sagan. Preus. Gothaab. Ginge. Salem. Holyoke. Lovering. Edsberg. Wilse. Copenhagen. Bugge. Edsberg. Wilse. Copenhagen. Bugge. Stockholm. Nicander. Salem. Holyoke. Lovering. Kendal. Dalton Edsberg. Wilse. Gottingen. Gatterer. Stockholm. Nicander. Berlin. Beguelin. Mannheim. Hemmer. Prague. Strnad. Prague. Strnad. Mannheim. Hemmer. Stockholm. Nicander. St. Petersburg. Euler. Stockholm. Nicander. Moscow. Stritter. Gothaab. Ginge. Stockholm. Nicander. Ronneburg. Dietmann. Gothaab. Ginge. Edsberg. Wise. Sagan. Preus. Mannheim. Hemmer. Gothaab. Ginge. Edsberg. Wilse. Paris. Cassini. St. Petersburg. Euler. Stockholm. Nicander. Mannheim. Hemmer. Sagan. Preus. Munich. Huebpauer. Buda, Bruna. Copenhagen. Bugge. Gothaab. Ginge. Peissenberg. Schwaiger. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Brussels. Mann.2 Paris. Cassini. Gothaab. Ginge. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. New Haven. Stiles. Edsberg. Wilse. Paris. Cassini. Mannheim. Hemmer. Brussels. Kendal. Dalton. Geneva. Senebier. Erfurt. Planer. Ratisbon. Heinrich. Stockholm. Nicander. Gottingen. Gatterer. St. Petersburg. Euler. Copenhagen Bugge. Peissenberg. Schwaiger. Berne. Studer. Rochelle. Seignette. Sutz. Spriingli. Boué.t Mannheim. Hemmer. Gothaab. Ginge. Loomis. Mann. 1 Sitz. Bericht. Wien. XLV. 445. 2 The observations at Brussels for 1787 do not appear to have been published in full either in the Mém. de Acad. Brux., or the Ephem. Soc. Met. Palat. There were thirty-three in all. Mém. de l’Acad. Brux. V. 457. bo bo bo tO POL Gat) DD bet fe pk eee le i i i i ee ee SHEOSGOHOOSOGOLONDDHONOTP PP PP YON a PPP PNyrpy! ON THE PERIODICITY OF THE AURORA BOREALIS. Munich. Wuebpauer. Sagan. Preus. Edsberg. Wilse. atisbon. Heinrich. Cambridge. Williams. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Stockholm. Nicander. Stoekholm. Nicander. Kendal. Dalton. Mannheim. Hemmer. Edsherg. Wilse. Copenhagen. Bugge. Montmorenci. Cotte. Mannheim. Hemmer. Stockholm. Nicander. Gothaab. Ginge. Rochelle. Seignette. Munich. Wuebpauer. Sagan. Preus. Cambridge. Williams. Jena. Zeissing. Gottingen. Gatterer. Copenhagen. Bugge. Erfurt. Planer. Edsberg. Wilse. Mannheim. Hemmer. Ratisbon. Weinrich. Sagan. Preus. Gothaab. Ginge. Stockholm. Nicander. Sagan. Preus. Gothaab. Ginge. Stockholm. Stockholm. Nicander. Sagan. Preus. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Uolyoke. Lovering. Stockholm. Nicander. St. Petersburg. Euler, Stockholm. Nicander. Sagan. Preuss. » Mannheim. Hemmer. Stockholm. Nicander. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Holyoke. Lovering. Stockholm. Nicander. Padua. Toaldo. Cambridge. Williams. . Salem. Holyoke. Lovering. Edsberg. Wilse. Stockholm. St. Petersburg. Euler. Rochelle. Seignette. Montmorenci. Erfurt. Planer. Kendal. Dalton. Padua. Toaldo. Sagan. Preus. Mannheim. Hemmer. Gottingen. Gatterer. Kendal. Dalton. Mannheim. Hemmer. Stockholm. Nicander. St. Petersburg. Euler. Copenhagen. Bugge. Copenhagen. Bugge. Rochelle. Seignette. Nicander. Nicander. Cotte. Rochelle. Seignette. “ Apr. 23. 26. May? 4. 10. 11. 12. 13. 13. 13. 13. 13. 13. 13. 13. 14. 14. 14. 15. 15. 15. 16. 16. 16. 16. 17. 17. 17. We 18. iS: 19. 21. Mannheim. Hemmer. Kendal. Dalton. Jena. Gottingen. Gatterer. Rochelle. Seignette. Ratisbon? Heinrich. Kendal. Dalton. Bologna. Matteucci. Prague. Strnad. Padua. Toaldo. Montmorenci. Cotte. Berne. Studer. Rome. Calandrelli. Buda. Bruna. Ratisbon. Heinrich. Sagan. Preus. Gottengen. Gatterer. Munich. Huebpauer, Stockholm. Nicander. Rochelle. Seignette. Paris. Cassini. Jena. Zeissing. Marseilles. Silvabella. Bologna. Matteucci. Gottingen. Gatterer. Prague. Strnad. Rochelle. Seignette. Paris. Cassini. Padua. Toaldo. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Rochelle. Seignette. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Holyoke. Lovering. Paris. Cassini. Kendal. Dalton. Cambridge. Williams. Kendal. Dalton. Salem. Wolyoke. Lovering. Rochelle. Seignette. Stockholm. Nicander. Rome. Calandrelli. Paris. Cassini. Kendal. Dalton. New Haven. Stiles. Loomis. Paris. Cassini. Erfurt. Planer. Mannheim. UWemmer. Montmorenci. Cotte. Rochelle. Seignette. New Haven. Stiles. Rochelle. Seignette. Prague. Strnad. Kendal. Dalton. Rochelle. Seignette. Cambridge. Williams. Paris. Cassini. Salem. Holyoke. Lovering. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Montmorenci. Cotte. Zeissing. Loomis. 1 An aurora was scen in Spain one day in this month. Mem. Acad. Cienc. Madrid. III. 77. ON THE PERIODICITY OF THE AURORA BOREALIS. Wigglesworth. Lovering. Williams. Stiles. Stiles. Williams. Hemmer. Rome. New Haven. Stiles. Loomis. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Erfurt. Planer. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Bologna. Matteucci. Mannheim. Hemmer. Padua. Toaldo. Rome. Calandrelli. Buda. Bruna. Sagan. Preus. Rochelle. Seignette. Lrfurt. Planer. Marseilles. Silvabella. Spain. Rico. Berne. Studer. Paris. Cassini. Berlin. Beguelin and Achard. Monimorenct. Cotte. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Bologna. Matteucci. Padua. Bologna. Matteucci. Salem. Holyoke. Lovering. Mannheim. Hemmer. Mannheim. Hemmer. Sagan. Salem. Holyoke. Lovering. Berlin. -Beguelin and Achard. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Uolyoke. Lovering. Ratisbon. Heinrich. Jena. Zeissing. Paris. Cassini. Kendal. Dalton. Gottingen. Gatterer. Berlin. Achard. Erfurt. Planer. Mount St. Gothard, Milan. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Holyoke. Lovering. Stockholm. Nicander. Paris. Salem. Holyoke. Lovering. Cambridge. Wigglesworth. Lovering. Cambridge. Williams. Salem. Holyoke. Lovering. Kendal. Dalton. Mannheim. Hemmer. Cambridge. Williams. Cambridge. Cambridge. New Haven. New Haven. Cambridge. Mannheim. Loomis. Loomis. Calandrelli. Toaldo. Preus. Cassini. Aug. 21. |) Sgueh SF 1Si0). Sept. 6. “ 6. “ 6. “ 6. “ 6. “ 6. “ re “ a(R “ ae “ 8. “ 9, C10: Ce ise Kas: Sess 19. 23. obs EL eos ily June? 3. “ 4, “ 5. aS 9: le De 2B: July 1. “ 2 “ oe ae “ 5. Sa. CHS “ 95 “ D5 ea 5195 SPE «22. LORE e526. OT, J pise SO: Dec. 8. Oe IGS “« 16, “« 90. Cae OH le Cog fODR Calg ES «93. CP 0 “ 24, « 25. « 26. “« 30. 89 St. Petersburg. Euler. Cambridge. Wigglesworth. Lovering. Salem. Wolyoke. Lovering. Spain. Rico. St. Petersburg. Euler. Jena. Moscow. Stritter. Rochelle. Geneva. Senebier. Delue. Marseilles. St. Jacques. Beziers. Bertholon. Padua. Toaldo. Rome. Calandrelli. Mannheim. Hemmer. Buda. Bruna. Sagan. Preus. Erfurt. Planer. Stockholm. Nicander. Kendal. Dalton. Sagan. Preus. Stockholm. Nicander. Geneva. Senebier. Sagan. Preus. Keswick. Dalton. Stockholm. Nicander. Sagan? Preus. Stockholm. Sagan. Preus. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. Sagan. Preus. Kendal. Dalton. Paris. Cassini. Kendal. Dalton. Stockholm. Nicander. Laon. Cotte. Geneva. Senebier. Kendal. Dalton. Erfurt. Planer. Sagan. Preus. Sagan? Preus. Stockholm. WNicander. Stockholm. Nicander. Sagan. Preus. Kendal. Dalton. Stockholm. WNicander. Stockholm. Nicander. Mannheim. Hemmer. Sagan? Preus. Kendal. Dalton. Kendal. Dalton. Stockholm. Nicander. Mannheim. Hemmer. Mannheim. Uemmer. Mannheim. Hemmer. Peissenberg. Schwaiger. Kendal. Dalton. Stockholm. Nicander. Sagan. Preus. Brussels. Paris. Cassini. Ratisbon. Berne. Studer. Stockholm. Nicander. Stockholm. Nicander. Stockholm. Nicander. Mannheim. Hemmer. Zeissing. Seignette. Nicander. Sagan. Preus. Kendal. Dalton. Mann. Heinrich. Kendal. Dalton: 1 Aurora Australis. Jan. 11. Cane Sif se 1 “24; 29. “« 30. Feb. 2. “ 6. SED; « “15: KD: “<~ HG: ths GOES caer “< 26: S52: sc 2G: « 28. Mar. 2. “ 3. “ 4, aE ale B uc: e145 ce aay “« 16. ee «20: Ke: 26: S26: OE DK Ti 67 le Di 5 OY. CRUE “27. Ce PL COT. So D7 cD. Ge «28. 28: 1 Mém 2 Nova ON THE PERIODICITY OF 1789. Stockholm. Nicander. Stockholm. Nicander. Sagan. Preus. Mannheim. UHemmer. Sagan? Preus. Sagan. Preus. Sagan. Preus. Kendal. Dalton. Stockholm. Nicander. Mannheim. Hemmer. Stockholm. Nicander. St. Petersburg. Euler. Cambridge. Wigglesworth. Lovering. New Haven. Stiles. Loomis. Berne. Studer. Stockholm. WNicander. Keswick. Dalton. Salem. Holyoke. Lovering. Stockholm. Nicander. Sagan. Preus. Kendal. Dalton. Stockholm. Nicander. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. Mannheim. Hemmer. Kendal. Dalton. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Stockholm. Nicander. Moscow. Stritter. Stockholm. Nicander. Moscow. Stritter. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. Kendal. Dalton. Spain. Rico. Brussels. Mann. Paris. Cassini. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Mannheim. WHemmer. Sagan? Preus. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Geneva. Senebier. Deluc. Berne. Studer. Brussels. Mann. Paris. Stockholm. Nicander. Marseilles. St. Jacques. Buda. Bruna. Mannheim. Hemmer. Rome. Jena. Zeissing. St. Petersburg. Euler.? Montmorenci. Cotte. Sutz. Spriingli. Ratisbon. Heinrich. Brussels. Mann. Sagan. Preus. Rochelle. Seignette. Sutz. Spriingli. Berne. Studer. Cassini. . de Acad. 1789. . Acta. Sci. Acad. Petrop. VII. 407. Ratisbon. Heinrich. Calandrelli. THE AURORA BOREALIS. Mar. 28. 29. 29. 29. 29. 30. 30. 31. Mannheim. Hemmer. St. Petersburg. Euler. Salem. Holyoke. Lovering. Kendal. Dalton. Brussels. Mann. Berlin. Achard. Sagan. Preus. Marseilles. St. Jacques. Berlin. Achard. Sagan. Preus. Brussels. Mann. Kendal. Dalton. New Haven. Stiles. Loomis. Sagan? Preus. Stockholm. Nicander. Brussels. Mann. St. Petersburg. Euler. Moscow. Stritter. Stockholm. Nicander. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Cambridge. Wigglesworth. Lovering. Stockholm. WNicander. Brussels. Mann. Stockholm. Nicandery Sagan? Preus. Stockholm. Nicander. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Stockholm. Nicander. Laon. Cotte. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. Sagan? Preus. Mannheim. Hemmer. Sagan? Preus. Kendal. Dalton. Brussels. Mann. Brussels. Mann. Mannheim. Uemmer. Salem. Holyoke. Lovering. Cambridge. Wigglesworth. Lovering. Salem. Wolyoke. Lovering. New Haven. Stiles. Loomis. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Ratisbon. Heinrich. Paris. Cassini. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. Rome. Calandrelli. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Brussels. Mann. Brussels. Mann. New Haven. Stiles. Loomis. Sagan. Preus. ON THE PERIODICITY OF THE AURORA BOREALIS. 91 Paris. Cassini. New Haven. Stiles. Loomis. Kendal. Dalton. Paris. Cassini. Ratisbon. Heinrich. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. New Haven. Stiles. Loomis. Ratisbon. Heinrich. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Salem. Holyoke. Lovering. Ratisbon. Heinrich. Salem. Holyoke. Lovering. Salem. Holyoke. Lovering. Salem. Holyoke. Lovering. Brussels. Mann. New Haven. Stiles. Loomis. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Brussels. Mann. New Haven. Stiles. Loomis. Brussels. Mann. Brussels. Mann. Salem. WHolyoke. Lovering. Brussels. Mann. Brussels. Mann. Paris. Cassini. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Zaon. Cotte. Salem. Holyoke. Lovering. Brussels. Mann. Keswick. Dalton. Stockholm. Nicander. Sagan. Preus. Kendal. Dalton. Paris. Cassini. Kendal. Dalton. Kendal. Dalton. Kendal. Dalton. Stockholm. Nicander. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. Kendal. Dalton. Kendal. Dalton. St. Petersburg. Euler. Peissenberg. Schwaiger. Sagan. Preus. Berne. Studer. Kendal. Dalton. Stockholm. Nicander. St. Petersburg. Euler. Stockholm. WNicander. Aug. 24. Cambridge. Wigglesworth. Lovering. « 24. Salem. Holyoke. Lovering. “ 24, Stockholm. Nicander. Paris. Cassini. “ 24. St. Petersburg. Euler. “ 25. Sagan? Preus. Ratisbon. Heinrich. « 25. Stockholm. Nicander. “ 25. Paris. Cassini. Kendal. Dalton. «“« 26. Stockholm. Nicander. “ 28. Stockholm. Nicander. « 29. Stockholm. Nicander. Sept. 9. Salem. Holyoke. Lovering. “ 10. Stockholm. Nicander. “ 12. Stockholm. Nicander. “ 13. Stockholm. Nicander. “ 14. Stockholm. Nicander. Kendal. Dalton. “ 15. Kendal. Dalton. “ 16. St. Petersburg. Euler. “ 17. Brussels. Mann. “ 20. Stockholm. Nicander. “ 20. Kendal. Dalton. Sagan. Preus. «21. Salem. Holyoke. Lovering. “21. Brussels. Mann. “ 22. Salem. Holyoke. Lovering. “ 23. Kendal. Dalton. “ 24. Sagan. Preus. “ 25. Sutz. Spriingli. Berne. Studer. “ 26. Kendal. Dalton. Falaise. Hervieu.2 «“ 26. Rochelle.- Seignette. Laon. Cotte. “ 26. Mannheim. Hemmer. “ 26. Peissenberg. Schwaiger. Berne. Studer. “ 26. Brussels. Mann. Paris. Cassini. “27.2 Stockholm. Nicander. Sagan? Preus. “ a. Falaise. Hervieu. Boué. Oct. 11.8 St. Petersburg. Euler. “ 12. Stockholm. Nicander. “ 13. Stockholm. Nicander. “ 16. Salem. Holyoke. Lovering. “18. Kendal. Dalton. St. Petersburg. Euler. “ 19. Cambridge. Wigglesworth. Lovering. « 19. Salem. Holyoke. Lovering. « 19. New Haven. Stiles. Loomis. “ 19. Kendal. Dalton. St. Petersburg. Euler. “ 19. Marseilles. St. Jacques. Moscow. Stritter. “ 20. Kendal. Dalton. St. Petersburg. Euler. “« 20. Jena. Zeissing. Moscow. Stritter. “ 20. Brussels. Mann. Paris. Cassini. 1 Encyc. Method. I. 368. 2 Journ. de Phys. XXXVI. 440. 5 An aurora was seen in Spain on one day of this month. ale il 6 743)5 Gi PBY e235 123. “ D4. 2: 6 CSI oy. 4. “ 6. “ 9, Cais Ch Cae: eo UA, AS “674. «4. « 18. « Wd: cee as alts Os © 420; Die BS OH 66922. 122. 245 «2D. se 65 is SO: “ x. Dec. 10. CS Ss ccm ATA eas S11); Cr USS SRLS. cc ealO: 20; ails “22. _ON THE PERIODICITY OF THE AURORA BOREALIS. Peissenberg. Schwaiger. Sagan. Preus. Holyoke. Lovering. Brussels. Mann. Cambridge. Wigglesworth. Lovering. Salem. Holyoke. Lovering. Kendal. Dalton. Stockholm. Nicander. St. Petersburg. Euler. Kendal. Dalton. Kendal. Dalton. Stockholm. Nicander. Kendal. Dalton. Peissenberg. Schwaiger. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Cambridge. Wigglesworth. Lovering. Salem. WHolyoke. Lovering. Hingham, Mass. Ware. Stockholm. Nicander. St. Petersburg. Euler. Salem. Moscow. Stritter. Kendal. Dalton. Kendal. Dalton. Cuba. Poey. Beziers. Betholon.1 Sagan. Preus. Rome. Calandrelli. Stockholm. Nicander. Stockholm. Nicander. Brussels. Mann. Sagan. Preus. Kendal. Dalton. Sagan. Preus. St. Petersburg. Euler. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Sagan. Preus. Kendal. Dalton. Kendal. Dalton. Stockholm. Nicander. Kendal. Dalton. Stockholm. WNicander. Kendal. Dalton. Stockholm. Nicander. Kendal. Dalton. St. Petersburg. Euler. Montmorenci. Cotte. Sagan. Preus. Salem. Holyoke. Lovering. Salem. Holyoke. Lovering. Sagan? Preus. Kendal. Dalton. Sagan? Preus. Sagan? Preus. Cambridge. Wigglesworth. Lovering. Sagan? Preus. Peissenberg. Schwaiger. ° Stockholm. Nicander. Mannheim. Hemmer. Sagan? Preus. 1 Encye. Method. I. 368. Dec. “ “ “ 23. 24. 26. 27. Stockholm. Nicander. New Haven. Stiles. Loomis. Paris. Cassini. Stockholm. Nicander. Stockholm. Nicander. 1790. Stockholm. Nicander. Sagan. Preus. Sagan. Preus. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Mannheim. Hemmer. Sagan. Preus. Stockholm. Nicander. Stockholm. Nicander. Laon. Cotte. Mannheim. Hemmer. Sagan. Preus. Jena. Zeissing. Prague. Strnad. Sagan. Preus. Kendal. Dalton. Stockholm. Nicander. Stockholm. WNicander. Kendal. Dalton. Stockholm. Nicander. Salem. Uolyoke. Lovering. Stockholm. Nicander. Sagan. Preus. Stockholm. Nicander. Salem. Holyoke. Lovering. Sagan. Preus. Stockholm. Nicander. Mannheim. Hemmer. Stockholm. Nicander. Sagan. Preus. Stockholm. Nicander. Brussels. Mann. Stockholm. Nicander. Mannheim. Hemmer. Stockholm. Nicander. Peissenberg. Schwaiger. Stockholm. Nicander. Brussels. Mann. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Sagan. Preus. Stockholm. Nicander. Stockholm. Nicander. Kendal. Dalton. Sagan. Preus. Stockholm. Nicander. atisbon. Heinrich. Sagan. Preus. Kendal. Dalton. Stockholm. Nicander. Mannheim. Wemmer. Kendal. Dalton. Stockholm. Nicander. Stockholm. WNicander. Kendal. Dalton. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Stockholm. Nicander. ON THE PERIODICITY OF THE AURORA BOREALIS. 93 Apr. 2. Mannheim. Hemmer. Stockholm. Nicander.|Sept. 6. New Haven. Stiles. Loomis. “3. Mannheim. Hemmer. Kendal. Dalton. “ 6. Stockholm. Nicander. “ 4, Mannheim. Hemmer. Kendal. Dalton. “ 7. Brussels. Mann. Kendal. Dalton. “ 4, Stockholm. Nicander. "95 Sagan: Breve: “5. Kendal. Dalton. “ 13. Stockholm. Nicander. “ 6. Mannheim. Hemmer. Kendal. Dalton. “ 16. St. Petersburg. Euler. “7. Kendal. Dalton. “ 19. St. Petersburg. Euler. “« 8. Mannheim. Hemmer. “ 24, Sagan. Preus. “« 9. Sagan. Preus. Kendal. Dalton. “ 30. Mannheim. Hemmer. Sagan. Preus. “ 9. Stockholm. Nicander. “ 30. Brussels. Mann. St. Petersburg. Euler. “ 10. Stockholm. Nicander. “ 30. Stockholm. Nicander. “ 11. Mannheim. Hemmer. Oct. 1. Mannheim. Hemmer. Stockholm, Nicander. “ 16. Stockholm. Nicander. Kendal. Dalton. «3. Stockholm. Nicander. “ 17. Stockholm. Nicander. Kendal. Dalton. “ 4, Sagan. Preus. St. Petersburg. Euler. “ 25. Stockholm. Nicander. “7. Pyschminsk, Siberia. Wermann.? “ 27. Stockholm. Nicander. “ 9. Mannheim. Hemmer. Kendal. Dalton. “ 30. Stockholm. Nicander. Brussels. Mann. “ 12. Stockholm. Nicander. May 1. Stockholm. Nicander. “ 14. Mannheim. TWemmer. “« 1. St. Petersburg. Euler.t “ 17. Stockholm. Nicander. «2. Stockholm. Nicander. “ 18. Keswick. Dalton. “3. Stockholm. Nicander. “ 380. Stockholm. Nicander. “ 6. Stockholm. Nicander. “ 31. Salem. Holyoke. Lovering. Kendal. Dalton. “ 10. Stockholm. Nicander. Noy. 1. Stockholm. Nicander. “ 11. Stockholm. Nicander. “« 4, Sagan. Preus. “ 12. Kendal. Dalton. “ 5. Sagan. Preus. “ 14. Kendal. Dalton. “ 6. Sagan. Preus. “ 16. Salem. Holyoke. Lovering. “ 7. Kendal. Dalton. “ 16. Sagan. Preus. Peissenberg. Schwaiger. | “ 8. Sagan. Preus. Kendal. Dalton. “ 16. Kendal. Dalton. Prague. Strnad. “ 9. Mannheim. Hemmer. “- 17. Salem. WHolyoke. Lovering. “ 9. Stockholm. Nicander. Kendal. Dalton. “ 18. Kendal. Dalton. “ 10. Salem. Holyoke. Lovering, “« 24. Brussels. Mann. “ 10. Kendal. Dalton. “ 30. Prague. Strnad. “ 11. Stockholm. Nicander. June 3. Salem. Holyoke. Lovering. Brussels. Mann.) “ 12. Sagan. Preus. Kendal. Dalton. “« 5. Brussels. Mann. “ 16. Kendal. Dalton. “« 8. Brussels. Mann. “ 17. Pyschminsh, Siberia. Hermann. “ 22. Petssenberg. Schwaiger. “ 26. Sagan. Preus. “ 25. Mannheim. Hemmer. “ 27. Kendal. Dalton. “ 30. Salem. Holyoke. Lovering. “ 28. Stockholm. Nicander. July 1. Salem. Holyoke. Lovering. “ 28. Pyschminsk. Hermann. Kendal. Dalton. «3. Salem. UHolyoke. Lovering. “ 29. Stockholm. Nicander. “« 3. New Haven. Stiles. Loomis. “ 30. Kendal. Dalton. “ 13. Jena. Zeissing. Dec. 9. Stockholm. Nicander. “ 16. New Haven. Stiles. Loomis. “ 10. Stockholm. Nicander. “ 16. Prague. Strnad. Sutz. Spriingli. “ 12. Stockholm. Nicander. Aug. 3. Mannheim. Hemmer. “ 25. Kendal. Dalton. “ 16. Salem. Holyoke. Lovering. “ 26. Stockholm. Nicander. “ 19. Berne. Studer. “ 26. Pyschminsk. Hermann. 1 Nova Acta. Sci. Acad. Petrop. VIII. 1 Ephem, Soc. Met. Palat. 1790. 2 Ephem. Soc. Met. Palat. 1790. 94 ON THE PERIODICITY OF THE AURORA BOREALIS. Dec. 28. Kendal. Dalton. . June10. Kendal. Dalton. « 30. Sagan. Preus. “« 19. Sagan. Preus. “ 26. Brussels. Mann. 1791. July 7. Mannheim. Hemmer. a Jan. 1. Stockholm. Nicander. “ 20. Brussels. Mann. « 6. Salem. Holyoke. Lovering. “ 22. Salem. Holyoke. Lovering. « 6. Kendal. Dalton. « 22. New Haven. Stiles. Loomis. « 6. Pyschminsk, Siberia. Hermann. “ 23. Salem. Holyoke. Lovering. « 6. Brussels. Mann. « 24. Salem. Holyoke. Lovering. « 6. Sagan. Preus. Stockholm. Nicander. “ 28. Salem. Holyoke. Lovering. « 7. Sagan. Preus. Stockholm. Nicander. Aug.15. Stockholm. Nicander. « 9. Sagan. Preus. “ 18. Mannheim. Hemmer. « 12. Salem. Holyoke. Lovering. “« 20. Mannheim. Hemmer. “ 12. Pyschminsk, Siberia. Hermann. Sept. 5. Stockholm. Nicander. Kendal. Dalton. “ 13. Pyschminsk, Siberia. Hermann. « 8. Kendal. Dalton. . “ 920. Mannheim. Hemmer. “ 11. Stockholm. Nicander. Kendal. Dalton. “« 25. Mannheim. Hemmer. “ 13. Kendal. Dalton. “ 28. Sagan. Preus. « 15. Mannheim. Hemmer. « 29. Sagan. Preus. “ 17. Pyschminsk, Siberia. Hermann. Feb. 21. Ratisbon. Heinrich. “ 19. Stockholm. Nicander. « 24, Sagan. Preus. “ 22. Stockholm. Nicander. «“ 25. Kendal. Dalton. “« 24. Stockholm. Nicander. «“« 27. Sagan. Preus. “ 27. Kendal. Dalton. Mar. 2. Sagan. Preus. « 28. Stockholm. Nicander. «“ 3, Kendal. Dalton. «“ 28. Brussels. Mann. Kendal. Dalton. « 5. Stockholm. Nicander. Kendal. Dalton. | “ 30. Stockholm. Nicander. “ %, Kendal. Dalton. Oct. 1. Stockholm. Nicander. « 20. Mannheim. Hemmer. “2. Munich. Imhof. « 922. Salem. Holyoke. Lovering. « 6. Sagan. Preus. « 26. Salem. Holyoke. Lovering. “ 15. Kendal. Dalton. « 26. Kendal. Dalton. : “ 19. Kendal. Dalton. « 99, Kendal. Dalton. “ 20. Kendal. Dalton. “ 31. Stockholm. Nicander. “ 21. Brussels. Mann. Apr. 1. Salem. Holyoke. Lovering. «“ 22. Brussels. Mann. Kendal. Dalton. «“ 1. Stockholm. Nicander. « 923. Sagan. Preus. Kendal. Dalton. “ 3. Kendal. Dalton. « 28. Prague. Strnad. « 4, Stockholm. Nicander. Uhleaborg. Julin. « 29. Stockholm. Nicander. Kendal. Dalton. « 5. Salem. Holyoke. Lovering. “ 31. Kendal. Dalton. “ 13. Mannheim. Hemmer. Nov. 3. Kendal. Dalton. « 18. Sagan. Preus. “ 4. Kendal. Dalton. « 20. Kendal. Dalton. « 5. Kendal. Dalton. “ 23. -Kendal. Dalton. “« 8. Mannheim. Hemmer. “« 25. Kendal. Dalton. “ 11. Kendal. Dalton. May 5. Padua. Toaldo and Chiminello. “ 14. Kendal. Dalton. “ 12. Kendal. Dalton. “ 16. Sagan. Preus. «“ 20. Kendal. Dalton. “ 17. Kendal. Dalton. “ 923. Brussels. Mann. “ 18. Brussels. Mann. Kendal. Dalton. «“ 96. Mannheim. Hemmer: * Brussels. Mann. “« 19. Sagan. Preus. Stockholm. Nicander. “ ; 1 1 Svenska Vetensk. Acad. XIV. 76, Voigt’s Mag. fr. Phys. 10. Baateeae XI. 3. p. 109. 1 Mem. Amer. Acad. II. 114. ON THE PERIODICITY OF THE AURORA BOREALIS. Kendal. Dalton. Stockholm. Nicander. Kendal. Dalton. Brussels. Mann. New Haven. Stiles. Loomis. Brussels. Mann. Kendal. Dalton. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Sagan. Preus. Brussels. Mann. Brussels. Mann. 1792. Kendal. Sagan. Kendal. Dalton. Sagan. Preus. Montreal Sagan. Preus. Brussels. Mann. Stockholm. Nicander. Kendal. Dalton. Stockholm. Nicander. Stockholm. Nicander. Stockholm. Nicander. Stockholm. Nicander. Stockholm. Nicander: Stockholm. Nicander. Kendal. Dalton. Mount St. Andex, Bavaria. Stockholm. Nicander. Kendal. Dalton. Sagan. Preus. Sagan. Preus. > Stockholm. Nicander. Sagan. Preus. Mannheim. Hemmer. Stockholm. Nicander. Mannheim. Hemmer. Kendal. Dalton. Isserstédt. Zeissing. Dalton. Preus. Kendal. Dalton. Kendal. Dalton. Hochholzer. Sagan. Preus. Stockholm. Nicander. Montmorenci. Cotte.? Sagan. Preus. Stockholm. Nicander. Kendal. Dalton. Sagan. Preus. Mannheim. Hemmer. Sagan. Preus. Kendal. Mannheim. Hemmer. Stockholm. Nicander. 1 Mém. Amer. Acad. IT. 115, 2 Journ. de Phys. XL, 450. Dalton. May “ 9, « 14, Saas Cee 20: C22. Serle June 2. << 30: July 7. Ce ats Less Cy A Aug. 2. “ 4, Pak cl li PRE iia Sept. 1. “ 6. “14 Se are “28: Oct.” 2. Cs Ip} en COTS: Us ilee “« 13. CSE “ 14, “ 14. “« 15. “ 16. Cle sco Ss e198 “« 23. “31. Nov. 7. «13; “ 14, OPrdiT. « 29. Dec, 2. 95 Stockholm. WNicander. Kendal. Dalton. Stockholm. Nicander. Brussels. Mann. Sagan. Preus. Sagan. Preus. Mannheim. Hemmer. Brussels. Mann. Montmorenct. Cotte. Brussels. Mann. Sagan. Preus. Kendal. Dalton. Salem. Holyoke. Lovering. Salem. Holyoke. Lovering. Salem. Holyoke. Lovering. Brussels. Mann. Mount St. Andex, Bavaria. Hochholzer. Kendal. Dalton. Mount St. Andex, Bavaria. Hochholzer. Kendal. Dalton. St. Petersburg. Euler2 Mannheim. Hemmer. Mannheim. Hemmer. Mannheim. Hemmer. Kendal. Dalton. Mannheim. UHemmer. Stockholm. WNicander. Kendal. Dalton. Salem. Holyoke. Lovering. New Haven. Stiles. Loomis. Kendal. Dalton. New Haven. Stiles. Loomis. Sagan. Preus. Isserstédt. Zeissing. St. Petersburg. Euler. Marseilles. St. Jacques. Brussels. Mann. Salem. Holyoke. Lovering. Sagan. Preus. Kendal. Dalton. Sagan. Preus. Sagan. Preus. Sagan. Preus. Sagan. Preus. Kendal. Dalton. Stockholm. Nicander. Kendal. Dalton. Kendal. Dalton. Stockholm. Nicander. Sagan. Preus. Sagan. Preus. Stockholm. Nicander. Kendal. Dalton. Moscow. Stritter.? 1 Nova Acta. Sci. Acad. Petrop. X. 505, 2 Nova Acta. Sci. Acad, Petrop, X. 505. 96 ON THE PERIODICITY OF THE AURORA BOREALIS. Dec. 7. Keswick. Dalton. “ 12. Padua. Toaldo and Chiminello. “ 13. Moscow. Stritter. “ 15. Salem. WHolyoke. Lovering. « 30. Sagan. Preus. 1793. Jan. 11. Kendal. Dalton. “ 12. Salem. Holyoke. Lovering. Kendal. Dalton. “ 18. Salem. Holyoke. Lovering. Kendal. Dalton. . “© 14, New Haven. Stiles. Loomis. “ 14, Pyschminsk, Mt. Oural, Siberia. Hermann. Feb. 8. Kendal. Dalton. « 12. Kendal. Dalton. “ 15. Kendal. Dalton. Thompson. Mar. 5. Kendal. Dalton. « 6. Kendal. Dalton. “ 13. Cambridge. Wigglesworth. Lovering. “ 13. Salem. Holyoke. Lovering. Kendal. Dalton. “ 30. Kendal. Dalton. Apr. 5. Kendal. Dalton. ae 9. Kendal. Dalton. “ 14. Kendal. Dalton. June 9. Montmorenci. Cotte.* Aug. 6. Salem. Holyoke. Lovering. “ 26. Montmorenct. Cotte. « 28. Salem. Wolyoke. Lovering. “« 928. St. Petersburg. Euler.’ Sept. 2. Salem. Holyoke. Lovyering. « 2. New Haven. Stiles. Loomis. “« 4, Cambridge. Wigglesworth. Lovering. Oct. 20. St. Petersburg. Euler. Noy. 8. Jsserstddt. Zeissing. 1794. Jan. 7. G. Britain or Ireland. Dalton.* “ 22. G. Britain or Ireland. Dalton. Mar. 8. G. Britain or Ireland. Dalton. « 99. G. Britain or Ireland. Dalton. Apr. 2. St. Petersburg. Euler.® « 3. St. Petersburg. Euler. « 30. Salem. Holyoke. Lovering. “ 30. Montmorenci. Cotte.® Noy.11. New Haven. Stiles. Loomis. Dec. 8. G. Britain or Ireland. Dalton. 1 Nova Acta Sci. Acad. Petrop. XI. 562. 2 Journ. de Phys. XLIII. 46, &e. 8 Nova Acta Sci. Acad. Petrop. XI. 562. 4 Met. Observ. and Essays, p. 218. 5 Nova Acta Sci. Acad. Petrop. XII. 524. 6 Journ. de Phys. XLIV. 297. Dec. 19. G. Britain or Ireland. Dalton. 1799. Mar.11. St. Petersburg. Euler.1 May 24. Salem. Holyoke. Lovering. Sept. 8. G. Britain or Ireland. Dalton. “ 14, G. Britain or Ireland. Dalton. Oct. 3. St. Petersburg. Euler. “ 14, Salem. Holyoke. Lovering. “ 18. G. Britain or Ireland. Dalton. 17962 Feb. 6. St. Petersburg. Euler. Apr. 6. Isserstddt. Zeissing. 1797. Jan. 22. G. Britain or Ireland. Dalton. Feb. 1. G. Britain or Ireland. Dalton. “ 10. St. Petersburg. Euler.® “ 18. G. Britain or Ireland. Dalton. “ 27. G. Britain or Ireland. Dalton. “ 28. G. Britain or Ireland. Dalton. Mar. 1. G. Britain or Ireland. Dalton. «“ 2. G. Britain or Ireland. Dalton. “ 10. G. Britain or Ireland. Dalton. Apr. 24. G. Britain or Ireland. Dalton. Nov.18. G. Britain or Ireland. Dalton. “ 21. G. Britain or Ireland. Dalton. “ 22. G. Britain or Ireland. Dalton. «“ 23. G. Britain or Ireland. Dalton. 1798. * Jan. 15. Montmorenct. Cotte. Feb. 10. Abo, Finland. Hiillstrém.* 1799. Jan. 22. St. Petersburg. Euler.® Feb. 10. Scotland. Graham. Boué.® “ 25. Eckwarden. Brandes.” July 23. Paris. Bouvard.® Sept. 3. G. Britain or Ireland. Dalton. “ .» 3. Paris. Bouvard. 1 Nova Acta Sci. Acad. Petrop. XIII. 582. 2 None in England or the United States of America this year. 8 Nova Acta Sci. Acad. Petrop. XIV. 795. * Gilbert Annal. XVIII. 74. 5 Nova Acta Sci. Acad. Petrop. XV. 563. 6 Trans. Roy. Soc. Edinb. V. 25. 7 Gilbert Annal. XXIV. 363. 8 Journ. de Phys. 29: PH). “ xr. Apr. 10. aloe 29: June 16. July 1. Sept.19. Se LOE 35 fe Dee. 13. Jan. 15. Mar. 19. SF «il Ge als) Apr. 12. G alge Aug. 23. Sept.11. ON THE PERIODICITY OF THE AURORA BOREALIS. G. Britain or Ireland. Dalton. 1800. G. Britain or Ireland. Dalton. G. Britain or Ireland. Dalton. G. Britain or Ireland. Dalton. 1801. G. Britain or Ireland. Dalton. G. Britain or Ireland. Dalton. G. Britain or Ireland. Dalton. G. Britain or Ireland. Dalton. Abo. Hiillstrém.1 Muncke? and Quetelet.* Abo. Hiillstrém. Muncke and Quetelet. Abo. Hiillstrém. Boué. Edinburgh. Brewster.* Muncke and Quetelet. 1802. Sweden. G. Britain or Ireland. Dalton. Sweden. Hiillstrém. Muncke and Quetelet. G. Britain or Ireland. Dalton. Sweden. Hiillstrém. Muncke and Quetelet. St. Petersburg. Euler.® Sweden. Hiillstrém. Boué. Sweden. Hiillstrém. Muncke and Quetelet. Sweden. Hiillstrém. Muncke and Quetelet. Salem. Holyoke. Lovering. New Haven. Dwight. Loomis. Schaageragt. Lat. 57.° Long. 8.° Muncke and Quetelet. G. Britain or Ireland. Dalton. G. Britain or Ireland. Dalton. Horner. 1803. New Haven. Dwight. Salem. Holyoke. Paris. Bouvard. New Haven. Leffingwell. Loomis. G. Britain or Ireland. Dalton. G. Britain or Ireland. Dalton. Salem. Holyoke. Lovering. G. Britain or Ireland. Dalton. Loomis. Lovering. 1 Gilbert. Ann. XVIII. 75. 2 Gehler. Physikal. Worterbuch. VII. 138 8 Nouveaux Mém. de l’Acad. Brux. XII. 61. # Edin. Journ. Sci. V. 74. 5 Mém. de l’Acad. St. Petersb. III. 346, VoL. X. 13 S Hiillstrém. Muncke and Quetelet. Cs OYE 22. © 22. 22. CIPD PPE S22 Noy. 5. «22% 1 Mém “ 4, Feb. 23. 628. Mar. 26. Apr. 30. May 27. 97 Salem. Holyoke. Lovering. G. Britain or Ireland. Dalton. Salem. Holyoke. Lovering. New Haven. Leffingwell. Loomis. G. Britain or Ireland. Dalton. G. Britain or Ireland. Dalton. 1804. G. Britain or Ireland. Dalton. Paris. Bouvard. Salem. Holyoke. Lovering. New Haven. Day. Loomis. G. Britain or Ireland. Dalton. G. Britain or Ireland. Dalton. Salem. Holyoke. Lovyering. New Haven. Day. Loomis. G. Britain or Ireland. Dalton. Salem. Holyoke. Lovyering. St. Petersburg. Inochodzow. Schnepfenthal.? Ausfeld. Muncke and Quetelet. St. Petersburg. Inochodzow. Paris. Bouvard. Berlin. Wrede. Halle. Gilbert.* Leipsic. Mollweide. London.* Paris. Lamark. Quetelet. Dorpat. Parrot.® Petersburg, Kinigsberg, Briigge, §c. Muncke. Salem. Holyoke. Lovering. G. Britain or Ireland. Dalton. G. Britain or Ireland. alton. 1805. St. Petersburg. Inochodzow. Carlisle. Pitt. Muncke. G. Britain or Ireland. Dalton. Salem. Holyoke. Lovering. G. Britain or Ireland. Dalton. Manchester. Muncke and Quetelet.® Carlisle. Pitt. Quetelet.’ G. Britain or Ireland. Dalton. Muncke.’ Quetelet. Quetelet. . de l’Acad. St. Petersb. III. 436. 2 Gilbert. Ann, XIX. 108. 8 Gilbert. Ann. XVIII. 252, XTX. 106. 4 Phil. Trans. 1805, Pt. I. Meteor. Journ. p. 21. 5 Edin. New Phil. Journ. [. 157. 6 Nicholson’s Journ. &c, X. 303. 7 Gilbert. Ann. XIX, 219. 8 Gehler. Physikal. Worterbuch, VII. 138. 98 May 28. Muncke. Quetelet. Aug.29. Milnegraden. Muncke. Quetelet. Sept.15. Salem. Holyoke. Lovering. “ 15. Mew Haven. Day. Loomis. PAN Muncke. Quetelet. 22. Muncke. Quetelet. “ 24. New Haven. Day. Loomis. “ 24. St. Petersburg. Inochodzow.? Paris. Bouvard. “24. G. Britain or Ireland. Dalton. Oct. 13. Muncke. Quetelet. “ 20. ——— Muncke. Quetelet. “ 22. ——— Muncke. Quetelet. Noy. 16. Muncke. Quetelet. “18. Salem. Holyoke. Lovering. ils Muncke. Quetelet. “« 19. ——— Muncke. Quetelet. “ 20. ——— Muncke. Quetelet. “« 25. —— Muncke. Quetelet. “ 26. —— Muncke. Quetelet. Dec. 26. ———— Muncke. Quetelet. 1806. Jan. 11. New Haven. Day. Loomis. Feb. 7. G. Britain or Ireland. Dalton. Mar.16. New Haven. Day. Loomis. Apr.13. Salem. Holyoke. Lovering. Aug. 9. St. Petersburg. Inochodzow. Sept.10. G. Britain or Ireland. Dalton. Oct. 2. Eckwarden. Brandes.® « 5. Salem. Holyoke. Lovering. Noy. 2. G. Britain or Ireland. Dalton. “ 2. Eckwarden. Brandes. Muncke and Quetelet. Dec. 22. Halle. Gilbert. Muncke. “ 22. Paris. Quetelet. 1807. Jan. 13. Halle. Gilbert. Muncke and Quetelet.5 Mar. 26. Border of Norway and Sweden. Hausmann.® “26. Muncke and Quetelet. Apr.11. New Haven. Day. Loomis. « 15. Lat. 66° NV. Long. 6° W. Scoresby.’ May 8. New Haven. Day. Loomis. 1 Ferussac. Bull. Univ. IX. 2 Mém. de l’Acad. St. Petersb. IV. 490. 3 Gilbert. Ann. XXIV. 363. * Gilbert. Ann. XXIV. 363. X XIX. 428. Gilbert. Ann. XXIV. 365. Reise Durch. Skandin. V. 259. 5 6 7 Arctic Regions. I. 417. ON THE PERIODICITY OF THE AURORA BOREALIS. 1808. Mar. 8. G. Britain or Ireland. Dalton. July 23. St. Petersburg. Petrow.t “ 31. Road from Leipsic to Halle. Gilbert.? 1809. Jan. 31. Salem. Holyoke. Lovering. Mar.19. Lat. 59° N. Long. 1° W. Scoresby. June 13. Salem. Holyoke. Lovering. 1810. Apr. 4. Lat. 71° W. Long. 3° EZ. Scoresby. 1811. Mar. 28. Lat. 67° W. Long. 2° E. Scoresby. “ 29. Lat. 67° WN. Long. 3° £. Scoresby. « 30. Lat. 68° WN. Long. 4° E. Scoresby. “ 31. Lat. 67° NW. Long. 4° #. Scoresby. 1814. Jan. 31. Salem. Holyoke. Lovering. Apr. 7. Tottenham. Howard. Muncke and Quetelet. “ 14. G. Britain or Ireland. Dalton. “ 17.4 Salem. Holyoke. Lovering. “ 17. New Haven. Day. Loomis. “ 17. Cineinnati.® Drake. Sept.10.° G. Britain or Ireland. Dalton. “ 11. Salem. Holyoke. Lovering. “ 11. New Haven. Day. Loomis. “ 11. Cineinnati. Drake. “ 11. G. Britain or Ireland. Dalton. “ 11. Glasgow. Dobbie.’ Oct. 22. Berne. Studer.® 1 Mém. de l’Acad. St. Petersb. VI. 682. 2 Gilbert. Ann. XXX. 243. Doubtful whether this was an aurora. 8 Gilbert. Ann. LI. 72. * In Gilbert. Ann. LI. 72, an aurora is mentioned as occurring jon April 11th or 17th. ® Drake’s Picture of Cincinnati. pp. 245-6. 5 The aurora was constantly observed at York Factory from Aug. 31st to Sept. 28th. Smith. Contrib. VIII. Record of | Auroral Phenom. &c. Force. p. 9. Chappel remarks: “ Dur- |ing our stay in Hudson’s Bay from Ang. 31st to Sept. 28th, 1814, /and upon our voyage home from thence, our nights were constant- ly illuminated by brilliant auroras.” p. 136. | 7 Phil. Mag. LVI. 175. 8 Mitth. Naturforsch. Gesellsch. Bern. 1855. p. 45. ON 1815. Apr. 5. Lat. 69° WV. Long. 2°. Scoresby. « 6. Lat. 70° WV. Long. 3°. Scoresby. “7. Lat. 70° N. Long. 4°. Scoresby. 1816. Sept.15. G. Britain or Ireland. Dalton. « 24. Glasgow. Dobbie.? « 26. Salem. Holyoke. Lovering. Oct. 7. Christiania. Hansteen.* “« 7. Munceke, Quetelet, and Biot.* 1817. Feb. 6. Paris. Muncke. Quetelet.® « 8. Letpsic. Mollweide.® Schubler.’ “ 8. G. Britain or Ireland. Dalton. «8. Sunderland. Pensey.8 Gosport. Burney. « 8. London, Leeds, and Derby. “« 8. Berne. Watt. Studer.?° « 8. Christiania. Hansteen. Biot. Germany. “8. Paris. Muncke and Quetelet. «9. K@énigsberg. Muncke and Quetelet. « 9. Letpsie. Mollweide.” “ 11. Stockholm. Muncke and Quetelet. « 18. Hamm. Gronau. Muncke and Quetelet. « 20. Walthamstow.4 Mar. 4. Carlsruhe. Studer. “5. Gordon Castle. Hoy. Glasgow. “ 15. Stockholm.® “« 16. Stockholm” “ 29. 19! OAT. 1) Se"). SU Nov. 8. a alil co) alae ali. 107 New York. Wough. Arago. New Haven. Herrick. Loomis. New York. Hough. Finmark. Keilhau. Finmark. Keilhau. Christian’s Sound. Graah.° Force. G. Britain or Ireland. Dalton. Perth. Muncke, Arago, and Quetelet. Finmark. YKeilhau. New York. Hough. Arago. Finmark. Keilhau. Tobolsk. Erman. Muncke. Arago and Quetelet. 1 Edin. Journ. Sci. X. 177. 2 Phil. Mag. IV. 392. 8 Pogg. Ann. XIV. 621. 4 Phil. Trans. 1829, p. 103, and 1839, p. 267. 5 Ann. Chem. et Phys. XX XIX. 418. Smyth’s Cel.Cye. I. 166. 6 Phil. Mag. IV. 337. 7 Edin. Journ. Sci. X. 146. 8 Edin. Journ. Sci. X.179. ® Narrative of an Expedition, &e. p. 48. 10 Pogg. Ann. XXII. 550, 22. bo & pv ewe bo bo bo bo DAAR bo bo Sons 31. | Ci ie io a ect ON THE PERIODICITY Finmark. Keilhau. Finmark. Keilhau. Finmark. YKeilhau. New York. Uough. Sharon, Conn. Smith. Loomis. St. Petersburg. Wisniewsky. Kupffer. G. Britain or Ireland. Dalton. Manchester. Blackwall. London.? Finmark. YKeilhau. Russia. Erman. Muncke. Arago and Quetelet. Finmark. Keilhau. Finmark. Keilhau. Finmark. Keilhau. Finmark. YKeilhau. Finmark. Keilhau. G. Britain or Ireland. Dalton. Finmark. Yeilhau. G. Britain or Ireland. Dalton. Manchester. Blackwall. Gosport. Burney. Muncke, Arago, and Quetelet. G. Britain or Ireland. Dalton. Arago and Quetelet. Finmark. Keilhau. Finmark. Keilhau. 1829.4 Finmark. Keilhau. Kendal. Marshall. Muncke. Arago and Quetelet. Finmark. YJeilhau. Finmark. Keilhau. New York. Hough. oO “ 17. G. Britain or Ireland. Dalton. eo ON. “ 17. Muncke, Arago, and Quetelet. eee Zas “ 18. Felix Harbor. Ross.” 28s “ 21. New York. Hough. «30. “ 21. Felix Harbor. Ross. 503 Fort Reliance. Back and King. Oct. 1 New York. Hough. ei se Ss Fort Reliance. Back and King. ea! Fort Reliance. Back and King. as Fort Reliance. Back and King. = See: Fort Reliance. Back and King. re Fort Reliance. Back and-King. cl ae Fort Reliance. Back and King. “28, Fort Reliance. Back and King. 7 2b. Fort Reliance. Fort Reliance. Fort Reliance. ‘ort Reliance. Fort Reliance. Tack and King. ge Fort Reliance. Back and King. | Bs Fort Reliance. Back and King. ee = ods Fort Reliance. Fort Reliance. Back and King. Back and King. Back and King. camer 4 (= Back and King. oe Back and King. Nov. 2. Back and King. ene. Back and King. Fort Reliance. Back and King. New York. Wough. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. Fort Reliance. Back and King. New York. Hough. Brussels. Quetelet. New York. Hough. New York. Hough. New York. Hough. United States. Quetelet. New York. UWough. New York. Hough. Nova Zembla. Uough. St. Petersburg. Wisniewsky. New York. Wough. New York. Uough. New York. WHough. New York. UHough. New York. Hough. New York. Hough. Fort Reliance. Back and King. New York. UHough. Fort Reliance. Back and King. Fort Reliance. Back and King. New York. Hough. New York. WHough. New Haven. Loomis. New York. Hough. Manchester. Kupffer. Dalton. Moseley. James, &c.? St. Petersburg. Wisniewsky. Kupffer. 1 Monatl. Corr. X. 2 Mem. Lit. and Phil. Soc. Manchest. VL 617. et PN OSB DNBRMHAMTP PE OWN NT Bee ee PHAM no S 20. 21. Fort Reliance. New Haven. New Haven. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Nova Zembla. Fort Reliance. Nova Zembla. Fort Reliance. Nova Zembla. Fort Reliance. Nova Zembla. Fort Reliance. Nova Zembla. Fort Reliance. New Haven. Fort Reliance. Nova Zembla. Nova Zembla. Fort Reliance. Fort Reliance. Nova Zembla. New York. Fort Reliance. New York. WHough. Fort Reliance. Fort Reliance. New Haven. Nova Zembla. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Nova Zembla. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. New York. Fort Reliance. New York. Hough. New Haven. ON THE PERIODICITY OF THE AURORA BOREALIS. Back and King. Loomis. Loomis. Back and King. Back and King. Back and King. Back and King. Back and King. Back and King. Back and King. Pakhtoussoff. Kupffer.t Back and King. Pakhtoussoff. Kupffer. Back and King. Pakhtoussoff. Kupffer. Back and King. Pakhtoussoff. Kupffer. Back and King. Pakhtoussoff. Kupffer. Back and King. Loomis. Back and King. Pakhtoussoff. Kupffer. Pakhtoussoff. Kupffer. Back and King. Back and King. Pakhtoussoff. Kupffer. Hough. Back and King. Back and King. Back and King. Loomis. Pakhtoussoff. Kupffer. Back and King. Back and King. Back and King. Back and King. Pakhtoussoff. Kupffer. Back and King. Back and King. Back and King. Back and King. Back and King. Back and King. Back and King. Hough. Back and King. 1 Annuaire Magnet. et Meter. de Russie. New Haven. Loomis. Loomis. Dee. 21. 22. 22. 22. 23. 23. 24. 25. 26. 27. 28. 29. 30. 3l. i . Sou PR Fort Reliance. Back and King. New York. Hough. New Haven. Loomis. Woolwich. Sturgeon.t Fort Reliance. New York. UWough. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Back and King. New Haven. Loomis. Back and King. Back and King. Back and King. Back and King. Back and King. Back and King. Back and King. Back and King. Back and King. 1835. Fort Reliance. Fort Reliance. Fort Reliance. New York. Fort Reliance. Back and King. Back and King. Back and King. Hough. ‘ Back and King. New York. Hough. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. New York. Fort Reliance. Fort Reliance. ‘ort Reliance. Nova Zembla. Fort Reliance. Fort Reliance. Fort Reliance. Fort Reliance. Back and King. Back and King. Back and King. Back and King. Back and King. Hough. Back and King. Back and King. 7 Back and King. Pakhtoussoff. Kupffer. Back and King. Back and King. Back and King. Back and King. New York. Hough. New Haven. Fort Reliance. Fort Reliance. Loomis. Providence. Caswell. Hanover, New Hampshire. Hough. Back and King. Back and King. New York.’ Hough. Fort Reliance. Fort Reliance. Nova Zembla. Fort Reliance. Nova Zembla. Fort Reliance. Back and King. Back and King. Pakhtoussoff. Kupffer. Back and King. Pakhtoussoff. Kupffer. Back and King. 1 Phil. Mag. VI. Third Series, 230. ON THE PERIODICITY OF THE AURORA BOREALIS. 117 Feb. 3. Nova Zembla. Pakhtoussoff. Kupffer. Noy.17. New Haven. Loomis.1 Providence. Caswell. “« = 4, Fort Reliance. Back and King. “ 17. Ashurst. Snow. Dunse. Steverson.? “« 4, Nova Zembla. Pakhtoussoff. Kupffer. “ 17. Prussia. 26: Mar. 12. eS: Sud; emG: Comet; CeO; ae ale CD22: « 623: “ 24, “« 26. « 30. « 30. “ 31. Apr. 12. ON THE PERIODICITY OF Yakoutsk. Kupffer. New Haven. Herrick. Newton and Loomis. St. Petersburg? and Yakoutsk. Kupffer. Kaafiord. "Thomas. Kaafiord. "Thomas. Kaafiord. "Thomas. New Haven. Herrick. Newton and Loomis. Providence, R. I. Caswell. Catharinebourg. Kupffer. Zlatoouste. Kupffer? Kaafiord. 'Thomas. Kaafiord. Thomas. Kaafiord. ‘Thomas. Catharinebourg. (Kupffer. Christiania. Hansteen. Kaafiord. Thomas. Christiania. Hansteen. Kaafiord. Thomas. New Haven. Herrick. Newton and Loomis. England. Hough. Dublin. Lloyd? New York. Hough. Boston. Hale. Lovering. Newberry. Johnson. New York. Hough. New Haven. Herrick. Newton and Loomis. Christiania. Hansteen. Catharinebourg. Kupffer. Barnaoul. Kupfter.2, Kaafiord. Thomas. New Haven. Herrick. Newton and Loomis. New York. Hough. Yakoutsk. (Kupffer. Christiania. Hansteen. New York. Hough. Yakoutsk. Kupffer. Christiania. Hansteen. Catharinebourg. Kupffer. New Haven. Herrick. Newton and Loomis. Kaafiord. Thomas. Kaafiord. ‘Thomas. New Haven: Herrick. Newton and Loomis. Christiania. Hansteen. New Haven. Herrick. Newton and Loomis. Christiania. Hansteen. Kaafiord. Thomas. Kaafiord. Thomas. Yakoutsk. Kupffer. Kaafiord. Thomas. Kaafiord. Thomas. Yakoutsk. Kupffer. Christiania. Hansteen. Yakoutsk. Kupffer. Kaafiord. Thomas. Catharinebourg. Kupffer. Yakoutsk. Kupffer. New Haven. Herrick. Newton and Loomis. 1 Annuaire Magnet. et Meteor. de Russie, 1839, p. 423. 2 Annuaire Magnet. et Meteor. de Russie, 1838, p. 26, 174 et 221. 8 Phil. Mag. Third Series, XII. 98. VOle) xo 16 THE AURORA BOREALIS. “ 30. May 1. “ “ “ 2. 13. 14. June 25. “ 25. 26. 26. 26. 27. July 13. 14, 15. 165. 15. 27. 27. 29. 29. Aug. 13. “ “ 22. 22. Zi 10. 12. 12. 12. 15. 13. 121 New York. Hough. Newberry. Johnson. Christiania. ansteen. Christiania. ansteen. New York. Hough. Christiania. Hansteen. Christiania. Hansteen. New Haven. Herrick. Newton and Loomis. New York. Hough. Brussels. Quetelet. Catharinebourg. Kupffer. New Haven. Herrick. Newton and Loomis. New York. Hough. Newberry. Johnson. Providence, R. I. Caswell. Newberry. Johnson. New York. Hough. Providence, R. I. Caswell. New Haven. Herrick. Newton and Loomis. New Haven. Herrick. Newton and Loomis. New York. Hough. New Haven. Herrick. Newton and Loomis. New York. Hough. Providence. Caswell. Macao, East Indies. Hough. New York. Hough. New Haven. Herrick. Newton and Loomis. New York. UWough. Boston. Hale. Lovering. New Haven. Herrick. Newton and Loomis. New York. UHough. New Haven. Herrick. Newton and Loomis. New York. Hough. New Haven. Herrick. Newton and Loomis New York. Hough. New York. Hough. New Haven. Herrick. Newton and Loomis. New York. Hough. Providence. Caswell. New Haven. Herrick. Newton and Loomis. Christiania. Hansteen. Yakoutsk. Kupffer. Catharinebourg. Kupffer. New Haven. Herrick. Newton and Loomis. New York. Hough. New Haven. Herrick. Newton and Loomis. New York. Hough. New Haven. Herrick. Newton and Loomis. New Haven. Herrick. Newton and Loomis. New York. Hough. Christiania. Hansteen. Catharinebourg. Kupffer. Bossekop, Finland. Lottin, &c.* Boston. Hale. Lovering. New Haven. Herrick. Newton and Loomis. 1 Bull. de l’Acad. Brux. V. 284. 2 Observy. Magnet. Comm. Nord. ON THE PERIODICITY OF THE AURORA BOREALIS. Bouvard.t Snow. New York. Hough. Paris. Bossekop. Lottin. 20: « 1205 Pile cas EDD: “ 26. cr 5263 26; 28; CIE Seascilis Noy. 1. “ pe “ 2. “ 4, “ 8. “ 9, «10: «AS; « 13: AS “ 15 “ 15 < 116: Ge allie KRG. S20) Ge eile 22: « 23: Gy yet GI “26: CPG Cie 24. “25. a0: July 4. “ 5. “ 8. “ 8. “ DA. 24. “ 24. «25. “« 628. « 3. Aug. 1. 13 ile Li aes “ 3. “ 4, SG. Sie “ 29. C29: “29. (SPR) GB BEY « 30. « 30. “« 30. “« 30. “« 31. Sept. 1. “ Ee “ Of. “ BY ON THE PERIODICITY OF THE AURORA BOREALIS. Makerstoun. Broun. Sitka. Kupffer. Makerstoun. Christiania. Hansteen. New Haven. Herrick. Newton and Loomis. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. New York. Wough. Makerstoun. Broun. New Haven? Herrick. Newton and Loomis. New Haven. Herrick. Newton and Loomis. Makerstoun. Broun. New York. Hough. New Haven? Herrick. Newton and Loomis. New Haven? Herrick. Newton and Loomis. New Haven? Herrick. Newton and Loomis. Worcester. UHerrick. Newton and Loomis. Toronto. Sabine. New York. Wough. Toronto. Sabine. Worcester. Herrick. Newton and Loomis. Toronto. Sabine. New Haven? Herrick. Newton and Loomis. Worcester. Herrick. Newton and Loomis. New York. Wough. Toronto. Sabine. New York. Uough. New Haven. Bradley. Newton and Loomis. New Haven. Herrick. Newton and Loomis. New Haven. Herrick. Newton and Loomis. New York. Hough. Toronto. Sabine. Toronto. Sabine. New York. WHough. New Haven. Herrick. Newton and Loomis. New York. Hough. New York. Hough. New Haven? Herrick. Newton and Loomis.” Worcester. Herrick. Newton and Loomis. Bilk. Schmidt. Huggate. Rankin.® Makerstoun. Broun. Dunse. Stevenson. Sitka. Kupffer. From Dusseldorf to Cologne. Schmidt. New Haven? Herrick. Newton and Loomis, New York. Hough. Montreal. Olmsted, Christiania. Hansteen. Makerstoun. Broun, Christiania. Hansteen. From Dusseldorf to Cologne. Jakobshavn. Rudolph, Christiania. Hansteen. Makerstoun. Broun. Toronto. Sabine. Broun. Schmidt. 1 Bull, de l’Acad, Brux. XII. Pt. Il. p. 226. 2 Bull. de Acad. Brux. XII. Pt. I- p, 745. © 8 Proc, Brit. Assoc. XV. 15. Sept. 4. 29. Gothaab. Block. New Haven. Herrick. Newton and Loomis. Toronto. Sabine. Gothaab. Block. New York. Hough. Gothaab. Block. Gothaab. Block. Gothaab. Block. Ausland. Boué. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. Jakobshavn. Rudolph. Toronto. Sabine. From Dusseldorf to Cologne. Schmidt. Cambridge. Bond. Lovering. New Haven? Herrick. Newton and Loomis. Toronto. Sabine. Gothaab. Block. From Dusseldorf to Cologne. Schmidt. Toronto. Sabine. Gothaab. Block. Bilk. Schmidt. Makerstoun. Broun. New York. Hough. Gothaab. Block. New Haven. Herrick. Newton and Loomis. Gothaab. Block. Makerstoun. Broun. Jakobshavn. Rudolph- Gothaab. Block. Jakobshavn. Rudolph. Gothaab. Block. Christiania. Hansteen. Jakobshawn. Rudolph. Makerstoun. Broun. Gothaab. Block. Gothaab. Block. Gothaab. Block. Gothaab. Block. Gothaab. Block. New York. Hough. New Haven. Herrick. Newton and Loomis. Jakobshavn. Rudolph. Toronto. Sabine. Makerstoun. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. Newberry. Johnson. New York. Hough. Gothaab. Block. Makerstoun, Broun. Jakobshavn. Rudolph. Gethaab. Block. Gothaab, Block. Gothaab, Block. Broun. Christiania. Hansteen, Makerstoun. Broun, Gothaab. Block. Christiania. Hansteen. Sitka. Kupffer. Gothaab. Block. Gothaab. Block. Christiania. Hansteen. Makerstoun. Broun. Christiania. Hansteen. Makerstoun. Broun. Gothaab. Block. Toronto. Sabine. ON THE PERIODICITY OF THE AURORA BOREALIS. Gothaab. Block. Makerstoun. Broun. Dunse. Stevenson. Gothaab. Block. Gothaab. Block. Gothaab. Block. Gothaab. Block. Jakobshawn. Rudolph. New Haven. Herrick. Newton and Loomis. Toronto. Sabine. Jakobshavn. Rudolph. New Haven. Herrick. Newton and Loomis. Gothaab. Block. Cambridge. Bond. Lovering. Gothaab. Block. New Haven. WUerrick. Newton and Loomis. New York. Hough. Manchester. Sturgeon. Eutin. Schmidt. Near Nottingham. Lowe.? Makerstoun. Broun. Dunse. Stevenson. Jakobshavn. Rudolph. Yakoutsk. Kupffer. Bonn. Schmidt. Amsterdam.’ Gothaab. Block. Cambridge. Bond. Lovering. Gothaab. Block. Gothaab. Block. Makerstoun. Broun. Bonn. Schmidt. Gothaab. Block. New Haven? Herrick. Newton and Loomis. Jakobshavn. Rudolph. Jakobshavn. Rudolph. Jakobshavn. Rudolph. Gothaab. Block. Ttheims. Coulvier-Gravier. Spain. Rico.* New Haven? Herrick. Newton and Loomis. Gothaab. Block. New Haven? Herrick. Newton and Loomis. Gothaab. Block. 1846. New Haven? Herrick. Newton and Loomis. London.® Gothaab. Block. Gothaab. Block. Gothaab. Block. Gothaab. Block. Gothaab. Block. Jakobshavn. Rudolph. Gothaab. Block. Gothaab. Block. Gothaab. Block. New Haven? Herrick. Newton and Loomis. 1 Phil. Mag. Third Series. XXVIII. p. 70. 2 Athenxum, 1845, p. 1203. 8 Poge. Ann. LX VII. 591. 4 Mem. Acad. Cienc. Madrid, III. 77. 5 L’Institut. Sci. Math. Phys. &c. XIV. 24. “ Apr. “ 141 New Haven? Herrick. Newton and Loomis. Gothaab. Block. New Haven. Herrick. Newton and Loomis. New York. Hough. Newberry. Johnson. New York. Hough. Gothaab. Block. Gothaab. Block. New Haven. Herrick. Newton and Loomis. New York. Hough. Providence. Caswell. Jakobshavn. Rudolph. New Haven? Herrick. Newton and Loomis. Gothaab. Block. Gothaab. Block. Newberry. Johnson. Bonn. Schmidt. Gothaab. Block. New Haven? Herrick. Newton and Loomis. Gothaab. Block. Gothaab. Block. Jakobshavn. Rudolph. Gothaab. Block. Gothaab. Block. Gothaab. Block. Jakobshavn. Rudolph. Gothaab. Block. New Haven. Herrick. Newton and Loomis. Newberry. Johnson. Providence. Caswell. Geneva. Schmidt. Makerstoun. Broun. Makerstoun. Broun. Jakobshavn. Rudolph. Gothaab. Block. Gothaab. Block. Gothaab. Block. Jakobshavn. Rudolph. Ohristiania. Tlansteen. Gothaab. Block. New Haven? Herrick. Newton and Loomis. Geneva. Schmidt. Gothaab. Block. Gothaab. Block. Makerstoun. Broun. New Haven. Herrick. Newton and Loomis. Christiania. Tansteen. Gothaab. Block. Gothaab. Block. New York. Hough. Christiania. Hansteen. Gothaab. Block. New York. Hough. Gothaab. Block. Gothaab. Block. Gothaab. Block. New Haven. Herrick. Newton and Loomis. Makerstoun. Broun, New Haven? Herrick. Newton and Loomis. New York. Hough. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. New York. Hough. Christiania. Hansteen. 18. 10. Hae 11. 12. 13. 14. ON THE PERIODICITY OF THE AURORA BOREALIS. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. New York. Wough. Providence. Caswell. Christiania. Hansteen. Makerstoun. Broun. Toronto. Sabine. - Toronto. Sabine. Ohristiania. Hansteen. New York. Uough. New York. Hough. New York. Hough. New Haven? Herrick. Newton and Loomis.}| Cambridge. Bond. Lovering. New York. Hough. Christiania. Hansteen. New Haven? Herrick. Newton and Loomis. Toronto. Sabine. New Haven. WUerrick. Newton and Loomis. New York. Hough. New Haven. Herrick. Newton and Loomis. New York. Hough. New York. Hough. New York. Hough. New Haven. Herrick. Newton and Loomis. New Haven. Herrick. Newton and Loomis. New York. Hough. Providence. Caswell. New York. WHough. New York. Hough. Toronto. Sabine. New York. Hough. Toronto. Sabine. At Sea. Lyell. Hough. New York. UHough. New Haven. Herrick. Newton and Loomis. New York. Wough. Cambridge. Bond. Lovering. New Haven? Herrick. Newton and Loomis. | New York. Uough. Toronto. Sabine. New Haven? Herrick. Newton and Loomis. New York. Hough. New York. WHough. New York. Hough. New York. Hough. New York. Hough. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. New Haven. Herrick. Newton and Loomis. Toronto. Sabine. New York. Hough. 1 Bull. de l’Acad. Brux. XIV. Pt. I. p. 420. Aug. 15. so S51'6: Giles BONE en D! <4, ode 2A. 24: ce: CEE CF Pl Sas. Sig i28: Sf). cc: ao: ca O Go Bile Sept. 1. SG) ao: ltt). «~ 10: ee ile Ge ati ah Ps, F118} ie SG \ieScieeesl Zio Sil. a2! cael CS. Oil Go Pile coe ile St Onl Cy PALS a2: PP. So PPR Ci OD. Le py. New York. Wough. Repulse Bay. Rae. Toronto. Sabine. New Haven? Herrick. Newton and Loomis. Christiania. Hansteen. Christiania. Hansteen. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. New York. Hough. Providence. Caswell. Christiania. Hansteen. Makerstoun. Broun. Christiania. Hansteen. Comrie, Perthshire. M’Farlane.} Christiania. Hansteen. Makerstoun. Broun. Bonn. Schmidt. Christiania. Hansteen. Toronto. Sabine. New Haven? Herrick. Newton and Loomis. Ridgefield, Conn. Bradley. Christiania. ansteen. New Haven? Herrick. Newton and Loomis. Christiania. Hansteen. New York. Hough. Christiania. Hansteen. New York. Hough. Cambridge. Bond. Lovering. New York. Wough. Makerstoun. Broun. Christiania. ansteen. Cambridge. Bond. Loyering. New York. Wough. Toronto. Sabine. Christiania. Hansteen. Makerstoun. Broun. Jakobshavn. Rudolph. Toronto. Sabine. Christiania. Uansteen. Toronto. Sabine. Christiania. Tansteen. Toronto. Sabine. Christiania. Hansteen. Jakobshavn. Rudolph. Christiania. Hansteen. Christiania. Hansteen. Christiania. Hansteen. Ashfield, Mass. Herrick. Newton and Loomis. New Haven. Herrick. Newton and Loomis. New York. Hough. Providence. Caswell. Toronto. Sabine. Durham. Chevallier. Norwich. Marshall.? Christiania. Hansteen. Comrie. M’Farlane. Makerstoun. Broun. Cambridge. Bond. Lovering. Ashfield, Mass. Herrick. Newton and Loomis. New Haven. Werrick. Newton and Loomis. Repulse Bay. Rae.® Toronto. Sabine. New York. Hough. Christiania. Hansteen. 1 Athenzeum, 1846, p. 917. 2 Proc. Brit. Assoc. XVI. 7. 8 Narrative of an Expedition, &c. ON THE PERIODICITY OF THE AURORA BOREALIS. Makerstoun. Broun. Hobarton. Sabine. Yakoutsk. Kupffer. Bonn. Schmidt. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. New York. Hough. Providence. Caswell. Hartford. Herrick. Newton and Loomis. Christiania. Hansteen. Christiania. Hansteen. New York. Hough. England. Hough. New York. Hough. Toronto. Sabine. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. New York. Hough. Makerstoun. Broun. Makerstoun. Broun. Toronto. Sabine. New Haven? Herrick. Newton and Loomis. New Haven. Herrick. Newton and Loomis. Toronto. Sabine. Christiania. Hansteen. Jakobshavn. Rudolph. New Haven. Herrick. Newton and Loomis. New York. Hough. Repulse Bay. Rae. Repulse Bay. Rae. Ireland. Hough. Repulse Bay. » Rae. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. New York. Hough. Newberry. Johnson. Christiania. THansteen. Toronto. Sabine. Makerstoun. Broun. Dunse. Stevenson. Jakobshavn. Rudolph. Christiania. Hansteen. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. New York. Hough. Christiania. Hansteen. Repulse Bay. Rae. Jakobshavn. Rudolph. New Haven. Herrick. Newton and Loomis. Newberry. Johnson. Makerstoun. Broun. Jakabshavn. Rudolph. New Haven. Herrick. Newton and Loomis. Jakobshavn. Rudolph. Repulse Bay. Rae. Repulse Bay. Rae. Jakobshavn. Rudolph. Repulse Bay. Rae. Repulse Bay. Rae. Repulse Bay. Rae. New Haven? Herrick. Newton and Loomis.? Bonn. Schmidt. 1 Amer. Journ. Sci. Second Series, ITI. 126. Noy. 13. GY ay “14, KG: Ch. a Si eg: P18; me 8: sis LG - eae (tof See ss Sa: J ait “« 19: Semel OE oe cs xy 9: ae IE aL Sie he “ 20. ‘520: J PAI cS 20! PAN 20. Qh Son Qle Sue DMR 26. 2. cas Mar. 4 1 Amer. Journ. Sci. Second Series, XIII. 426. 161 New Haven. Olmsted. Litchfield. Hendrick? Ohristiania. Hansteen. Yakoutsk. Kupffer. New Haven. Herrick and Olmsted. Litchfield. Hendrick. Burlington. Thompson. Christiania. Hansteen. Hammerfest. Noodt. New Haven. Werrick. Newton and Loomis. Providence. Caswell. Christiania. Hansteen. Cambridge. Bond. Loyering. New Haven. WUerrick and Olmsted. Burlington. Thompson. Newberry. Johnson. Catharinebourg and Sitka. Kupffer. Yakoutsk and Ichim. Kupffer.? Christiania. Hansteen. Kertchinsk. Kupffer. Cambridge. Bond. Lovering. New Haven. Herrick and Olmsted. Burlington. Thompson. Newberry. Johnson. Litchfield. Wendrick. Rochester. Dewey. Tennessee. Morris. San Francisco.* Gibbon. Dunse. Stevenson. St. Ives, Hunts. Watts.‘ Bonn. Schmidt. Jahn. Barnaoul and Kertchinsk. Kupffer.$ Christiania. Ulansteen. Jchim. Kupffer. Cambridge. Bond. Lovering. New Haven. Herrick. Newton and Loomis. Litchfield. Hendrick. Newberry. Johnson. Yakoutsk and Tobolsk. Kupffer. Christiania. Hansteen. Verden. Pape. Leipsic, ce. Jahn. Christiania. Hansteen. Tobolsk. Kupffer. Hammerfest. Noodt. Dunse. Stevenson. St. Jves, Hunts. Watts. Cambridge. Bond. Lovering. Burlington. "Thompson. Sitka. Kupffer. Cambridge. Bond. Lovering. Christiania. Hansteen. New Haven. Herrick. Newton and Loomis. Litchfield. Hendrick. Burlington. Thompson. Christiania. “Hansteen. Sitka. Kupffer. New Haven. Herrick. Newton and Loomis. Christiania. Hansteen. Burlington. "Thompson. Jahn. . 2 Annal. de l’Observ. Phys. Centrale de Russie, 1859, Supp). p. 95. 8 Dr. Gibbon says, that he saw the aurora at San Francisco, once in January, and once in February, 1852. Smithsonian Re- ports, 1854, p.258. Amer. Jour. Sci. Second Series, XX VII. 260. * Proc. Brit. Assoc. XXI. 32. 5 Annal.de l’Obsery. Phys. Centrale de Russie, 1852, pp. 127, 213, 311, et 561. 162 Mar. 12. SnD ly Ea51(9) ce 0) J ase le Se) Sos Ch AR Public. de YOtnew. Acer Goovnd Garis, L 20. Aaner. Sour, $i. Keoond Bories, KIK a2. 2 Samal. de YOkuary. Phys. Coumalle de Raatie, 1469, pp. 214, ADT. ® Saver. Jou, Gi. Hooond Gories, COVILL sev. ® Aavor. Jom. Goi. Booed Heries, NIT. se Aanall de Y Osan. Pope. Contuale de Kassie, 1659, p. £92. © Minho. ave dew Onmilonte. XV. 2. 23. 22. 12. 12. ON THE PERIODICITY OF THE AURORA BOREALIS. Catharinebourg. Zlatoouste. Kupffer. Cambridge. Bond. Lovering. Sitka. Kupffer. 385, 505, et 539. Marquette, Lake Superior. Dewey. GB} Hammerfest. Noodt. “14, Hammerfest. Noodt. uP Ge Hammerfest. Noodt. 18; Hammerfest. Noodt. *|May 6. Newberry. Johnson. June 22. Hammerfest. Noodt. 30: 1860. oe cel s Haparanda, Sweden. Bibm.? ng: Cambridge. Bond. Lovering. Dorpat. Bobm.| « 19, Hammerfest. Noodt. Jape (B Haparanda. Bohm. Hammerfest. Noodt.| « 7, Haparanda. Bohm. “« 8 Bogoslowski. Kupffer.? Hammerfest. Noodt.| « — g. Haparanda. Bohm. Go Haparanda. Peckeloh. Bohm. “« 49, Newberry. Johnson. “ 9, Worcester. Bemis. ee STi Newberry. Johnson. Providence. Caswell. “ 40. Stockholm. St. Petersburg. Reval. Bohm.| « 40, Zilatoouste. Kuptter.® “ 41. Bogoslowski. Kupffer. Haparanda. Bohm. “ 419. Copenhagen. Stockholm. Bohm. G eh Haparanda. Bohm. “ 42. Newberry. Johnson. Sitka. Kupffer.* “« 713. Sitka. Kupffer. ccs Worcester. Bemis. Newberry. Johnson. “ 46. Worcester. Bemis. “ 47, Newberry. Johnson. Bogoslowski. Kupffer. | « jg. Worcester. Bemis. “« 92. Bogoslowski. Kupffer. “ 25, Cuba. Bohm. “ 97. Worcester. Bemis. Providence. Caswell.| « 39, Cambridge. Bond. Lovering. Sept. 6. Worcester. Bemis. “ 6. Bogoslowski. WKupfter. a {R Catharinebourg? and Bogoslowskt. Kupffer. | « 7, Stockholm. Bohm. « 7, Newberry. Johnson.* Bogoslowski. Kupffer. | « Copenhagen. Paris. Dorpat. Bibhm. B Fi) Worcester.6 Bemis. GT. Hamburg and Haparanda. Bohm. 1 Reports of Regents of Univ. New York, 1860, p. 229. 2 Magnet. and Meteor. Beobacht. zu Prag. XXI. Jahr. p- IX. 3 Annal. de l’Obsery. Phys. Centrale de Russie, 1860, pp. 131, * Reports of Regents of Univ. New York, 1863, p. 415. 5 Twenty-eighth Report of the Lunatic Asylum, p. 68. Apr. 13. 13. “ Cambridge. Bond. Lovering. Worcester. Bemis. Newberry. Johnson. Providence. Caswell. Hamburg and Haparanda. Bohm. Cambridge. Bond. Lovering. Worcester. Bemis. Worcester. Bemis. St. Petersburg. Kupffer. Lougan. Kupffer. Worcester. Bemis. Sacramento, Cal. Logan.’ Newberry. Johnson. Cambridge. Bond. Lovering. Worcester. Bemis. Newberry. Johnson. Worcester. Bemis. Prague. Vienna. Berlin. Bohm. Chicago, Illinois. Bradley.® Naugard and Athens. Bohm. Zlatoouste and Lougan. Kupffer. New Haven. Herrick.* Prussia. France. Greece. Heis.® Bohm. New Haven. Herrick. Cnicago. Bradley. Paris. Heis. Norderney. Bohm. St. Petersburg. Kupffer. Prague and Peckeloh. Bihm. Chicago. Bradley. Bogoslowski. Kupffer. Prague. Weis. Catharinebourg. Kupffer. Bohm. Heis. Bohm. Paris. Kremsmunster, &c. Emden and Westphalia. Athens. Heis. Bohm. Worcester. Bemis. Chicago, Illinois. Newberry. Johnson. Bradley. Bemis. Stockholm. Newberry. Johnson.° Vestphalia. Westphalia. Bohm. Gouda, Netherlands. Cambridge. Bond.* Lovering. Worcester. Bemis. Newberry. Johnson. Utrecht, Stockholm, Peckeloh. Béhm. New Haven. Herrick.’ Sitka. Kupffer. Stockholm and Leipsic. Bohm. Peckeloh. Bohm. Stockholm and Haparanda. Worcester. Worcester. Bohm. Bohm. Bohm. Bohm. Bemis. 1 Annal. de l’Obsery. Phys. Centrale de Russie, 1860, p. 49. ? Annal. de l’Observ. Phys. Centrale de Russie, 1860, p. 573. 3 Amer. Jour. Sci. Second Series, XX XI. 136, and XXXII. 148. * Amer. Jour. Sci. Second Series, XXX. 298. 5 Bull. de ’Acad. Brux. X. 417 et 422. § Aurora Australis. 7 Bull. de l’Acad. Brux. Second Series, X. 420. oo Fm OO Mm ON THE PERIODICITY OF Cambridge. Bond. Lovering. Newberry. Johnson. Worcester. Bemis. Kreuznach, Prussia. Bohm. Worcester. Bemis. Cambridge. Bond. Lovering. Hammerfest. Noodt. Haparanda. Bohm. Cambridge. Bond. Lovering. Worcester. Bemis. Zlatoouste. * Kupffer. Hammerfest. Noodt. Hammerfest. Noodt. Munster. Weis. Peckeloh. Bohm. Hammerfest. Noodt. Catharinebourg. Kupffer. St. Petersburg. Kupffer. Worcester. Bemis. Catharinebourg. Kupffer. Hammerfest. Noodt. 1861. Hammerfest. Noodt. Zlatoouste. Kupffer. Worcester. Bemis.? Cambridge. Bond. Lovering. Cambridge. Bond. Lovering. Munster and Peekeloh. Weis. Dorpat. Bohm.” Locle. Kopp! Elberfeld. Bohm. Cambridge. Bond. Lovering. Worcester. Bemis. Peckeloh. Feis. Hammerfest. Noodt. Prague. Bohm. Hammerfest. Noodt. Hammerfest. Noodt. Cambridge. Bond. Lovering. Worcester. Bemis. Newberry. Johnson. Rochester. Dewey. Prague. Bohm. Rochester. Dewey. Haparanda. Bohm. Peckeloh. Bohm. Athens. Heis.® Rochester. Dewey. Hammerfest. Noodt. Cambridge. Bond. Lovering. Neuchatel. Kopp.* Brussels. Quetelet.5 Twenty-ninth Report of the Lunatic Asylum, p. 61. Magnet. und Meteor. Beobacht. zu Prag. XXII. Jahr. p. x11. Bull. Soc. Sci. Nat. Neuchatel. VI. 237. Reports of Regents of the Univ. New York, 1862, pp. 412, 421. Bull. de ’ Acad. Brux. XI. 317 et 644. THE AURORA BOREALIS. Ws (Mar. 9. St. Petersburg. WKupfter.1 Munster. Heis. oe 9. Haparanda and Stockholm. Bohm. “« 9. Greenwich. Paris. Cracow. Bohm. “9. Prague. Berlin. Dorpat. Bohm. “ 11. Newberry. Johnson. “ 13. Stockholm. Bohm. “« 344. Stockholm. Bohm. “ 17. Haparanda. Bohm. 19. vzern. Bohm: “25. Stockholm and Prague. Bohm. “ 26. Stockholm. Bohm. “ 28. Newberry. Johnson. Apr. 7. Sitka. Kupffer.? “ 11. Newberry. Johnson. “ 15. Haparanda and Munster. Bohm. “ 15. Peckeloh and Berlin. Bohm. June 12. Worcester. Bemis. Aug. 1. Rochester. Dewey. = «5. Cambridge. Bond. Lovering. 2. Near Lake Superior. Sand. Rive.* Sept. 8. Worcester. Bemis. “ 15. Worcester. Bemis. Newberry. Johnson. Oct. 10. Newberry. Johnson. Rochester. Dewey. “24. Worcester. Bemis. “ 25. Newberry. Johnson. “ 27. Newberry. Johnson. Nov. 5. Peckeloh. Bohm. “ 7%. Lichtenberg, Peckeloh, &c. Bohm. Dee. 1. Christiania. Hansteen.* “ 4. Stockholm. Peckeloh. Bohm. “« 5. Ohristiania. Wansteen. “ 18. Christiania. WHansteen. “ 19. Christiania. Dorpat. Dresden. Bohm. « 29. Haparanda. Ballot.t 1862. Jan. 1. Christiania. Ballot. “ 2. Haparanda. Ballot. “« 31. Stockholm. Ballot.* Feb. 1. Christiania. UHansteen. ue 2. Christiania. Hansteen. “ 7. Stockholm. Ballot. “ 98. Christiania. Wansteen. Mar. 1. Stockholm. Ballot. ue 5. Haparanda. Ballot. 1 Annal. de l’Observ. Phys. Centrale de Russie, 1861, pp. 45 et 537. 2 Annal. de l’Observ. Phys. Centrale de Russie, 1861, p. 455. 3 Mém. de la Soc. de Phys. Geneva, X VI. 330. + Nederlandsch. Meteorol Jaarboek. 1862, p. 319. 174 Mar. 7. calios Apr. 27. May 14. July 27. Aug. 4. Piel Salts 22: 2s: 29° U3 a0) Sept. 1. iG. “ Li. 20: Pile 2a: cn 24: Sa Doe ce 205 ce 26: CS il Oct. 3. Ke 4, Us sal), Bali ce ae Lo BE 2G: “ 29. «30. Nov. 10. Gn NG Dee. 14. G3 ile! i DEY C24. Ge Jan. 25. 1 Reports of Regents of the Univ. New York, 1863, p. 415. 2 Thirtieth Report of the Lunatic Asylum, p. 116. 3 Corr. Annuell. des Mines de Russie, 1860, p- XXVIII. # Bull. Soc. Sci. Nat. Neuchatel. VI. 279. 5 Annuaire de l’Observ. Royal de Brux. 1864, p. 200. ® Thirty-first Report of the Lunatic Asylum, p. 68. ON THE PERIODICITY OF THE AURORA BOREALIS. Hansteen. Hansteen. Christiania. Christiania. Newberry. Johnson.? Christiania. Hansteen. Leipsic. Ballot. Worcester. Bemis.? Christiania. Hansteen.| Worcester. Bemis. Worcester. Bemis. Newberry. Johnson. Worcester. Bemis. Christiania. Hansteen. Worcester. Bemis. Newberry. Johnson. Worcester. Bemis. Newberry. Johnson. Christiania. Hansteen. St. Petersburg and Dorpat. Christiania. Hansteen. Haparanda. Ballot. Christiania. Hansteen. Christiania. Ballot. Worcester. Bemis. Christiania. Tansteen. Worcester. Bemis. Newberry. Johnson. Christiania. Flansteen. Newberry. Johnson. Christiania. Hansteen. Worcester. Bemis. ‘ Christiania. Hansteen. Christiania. Hansteen. Petersburg. Ballot. Reval, Russia. Iwanoff.* Montpellier. Ballot. Stockholm. Ballot. Christiania. Tansteen. Cherbourg? Ballot. Christiania. Hansteen. Christiania. Hansteen. Christiania. Hansteen. Christiania. Hansteen. Neuchatel. Wirsch.t Brussels. Quetelet.5 Christiania and Europe generally. Ballot. Newberry. Worcester. Christiania. Ballot. Johnson. Bemis.° Christiania. Hansteen. Hansteen. 1863. Christiania. Hansteen. Jan. 26. ° fe 8% Feb. 7. “ 8: on BRE ee eA: So: KG > Mar. 21. De yey oi). Apr. 9. Seas “ 9, lis, Gs So ile 4G iit cote Sal. Ke 24° May 8. Aug. 14 Sept. 9. Js PRE “ 24. Ces Oct. 5. “ tes “ 9. wh altay 3 NG /e S20: Noy. 5 «> 13. cpt: June 7. Aug. 14. Sept. 20. Noy. 19. Christiania. ansteen. Christiania. Hansteen. Christiania. ansteen. Worcester. Bemis. Ohristiania. Hansteen. Christiania. Hansteen. Stockholm. Ballot2 Christiania. Tansteen. Christiania. Hansteen. Christiania. Wansteen. Stockholm. Ballot. Christiania. Hansteen. Christiania. Hansteen. Worcester. Bemis. Christiania. Hansteen- Christiania. Hansteen. Worcester. Bemis. New Haven Newburyport, Mass. Perkins. Christiania. Hansteen. Stockholm. Ballot. Christiania. Hansteen. Christiania. Tansteen. Christiania. Hansteen. Worcester. Bemis. Worcester. Bemis. Christiania. Wansteen. Munster. Heis. Christiania. Hansteen. Worcester. Bemis. Christiania. Hansteen. Worcester. Bemis. Worcester. Bemis. Christiania. Hansteen. Christiania. Hansteen. Haparanda. Ballot. Christiania. Hansteen. Haparanda. Ballot. Christiania. Hansteen. Christiania. Hansteen. Christiania. Wansteen. Christiania. Hansteen. Christiania. THansteen. Christiania. Hansteen. 1864, Cambridge. Lovering. Campton, New Hampshire. Lovering. Cambridge. Bond. Lovering. Cambridge. Lovering. 1 Nederlandsch. Meteorol. Jaarboek. 1863, p. 319. 2 Amer. Journ. Sci. Second Series, XXXV. 462. ON THE PERIODICITY OF THE AURORA BOREALIS. Jt te si Bl dper 175 I. AURORAS OBSERVED AT CAMBRIDGE, MASS., ARRANGED BY YEARS AND MONTHS. Year. 1742 1743 1744-5 1746 1747 1748 1749 1750 1751 1752 1753 1754-6 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 Jan. Sepa Feb. Cobo ee bos + Re ee. pores. - NR e- bore. -: hee. - pete oe Here ne: iS i ee Apr. ep pe: » me Oboe: Go. Go bo bo CO: Se. Cue bee: Total 17 3l 24 more bo+ Co- 26 Ct » WONG. di Cre OD. - NWR NWRRe- » wown-. 40 ssi 2 : 1 1 1 2 1 2 eae at foe B stadt 92 eaicenis 1 2 1 1 : 2 1 l 1 3 ; ; 1 bi a 1 5 2 : 2 2 3 : 1 2 2 oll | ean ee 2 1 3 2 Bo ql) Behe a. tee 1 1 2 2 3 2 2 4 3 7 4 ; : 2 1 Pgs tl. 49 | 82 | 81 +) Dee. 8 c~] Es a aa at i RPAAWONRKFANUIANEROKENUNOCHAOCNOCONWN — OPENER ORRETIANV EH 33 176 ON THE PERIODICITY OF THE AURORA BOREALIS. Il. AURORAS OBSERVED AT CAMBRIDGE, MASS., ARRANGED BY YEARS AND MONTHS. , Year Jan. Feb. > Ls} a 1340 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1855 1854 1855 1856 1857 1858 1859 1860 1861 1862-8 Total 1864 me OOo. CS mm. ee oe 27 Ke Ree ee Pe en- 37 Ws WNWNMWE Ws Woe me OCOtDe. - DOK OG. 39 May Sr ee oe 21 June July Aug. Sept. Oct. Noy. he no 10 1 2 1 -_ =e bo. Il 1 - — ee RO-e Nwron-: bo Co ee GO- 4 o_ ee. a Se . hee Dec. 29 20 45 17 19 Ill. AURORAS OBSERVED AT BOSTON, ARRANGED BY YEARS AND MONTHS. Jan. Feb. Apr. _ May June July OM GG — Aug. Sept. Oct. Nov. Total 1 _ ‘ FR ONNWNWHENOWOOCWONDOHR CH RE oo a ON THE PERIODICITY OF THE AURORA BOREALIS. agg IV. AURORAS OBSERVED AT SALEM, MASS., ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July ty Aug. Sept. Oct. Noy. Dec. Total |] 1786 : 2 6 5 2 2 7 4 3 4 3 a |e 11787 1 5 2 3 2 2 5 etl avd 3 2 D 33 | 1788 2 1 : 5 é : 4 5 Tf 4 t : 23 1789 } 2 4 2 6 6 5 2 3 4 1 2 37 1790 : 2 ; : 2 2 2 1 1 1 ; 11 1791 2 é 2 2 . 4 : ; 1 11 11792 : : : ‘ 3 2 1 6 1793 2 Roly al : ; 2 1 ; 6 1794 : : . 1 : . P : : : 1 1795 ; 5 . : 1 c : : ; 1 2 1796). 0 1801 5 . . . e . bed ° 1802 5 ; nie ale f 1 ; i ; 1 1803 : 2 1 ; : ‘ ; 1 2 , : 4 1804 ? ; : 1 2 : 5 é . : 1 4 1805 1 ; : ; : : ; é 1 : 1 3 1806 ; : é 1 ; : ; : : 1 : 2 | 1807-8 : ; : ; : ; : f ; é ; 0 11809 | 1 . ; ; ; 1 : : : ; é 2 TeO—03) ©. : ; eS ae : : : : : : 0 1814 é 1 : 1 ; A 5 4 1 , ’ 3 1815 : : ; : : . : é 1 1 1816-17) . : 5 : ; : ; . : 0 1818 : Z ; 5 : : : i 1 5 ; 1 1819 : 1 2 ; : : : : i 4 2 5 1820 , ; : 1 : ; ; : ; 1 Total 9 14 18 17 15 15 30 17 21 22 12 Seales Vv. AURORAS OBSERVED AT WORCESTER, MASS., ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Total 1839 1 3 1 4 : : . 4 2 3 i8 1840 4 il 2 il 1 2 4 P 1 4 4 24 1841 2 2 3 : : 2 Dev ly ay ; 1 ileal 14 1842 2 3 : ee 2 : ‘ : - 1 12 1843 5 - 3 : : : 2 : : 1 6 1844 ; é : 1 a eee . 1 : : 2 1845 1 1 F 1 : 1 2 1 ; 1 ‘ 8 11846 1 1 : 1 : 1 j : 1 1 1 7 |1847 : f 1 ; : : : : 1 : 2 1 5 1848 NN ey : 3 1 : he : : 1 3 1 13 1849 ; : 3 1 : ‘ : , 1 : : : 5 1850 ; : : 1 2 : if i , 2 6 11851 ; f 1 ; 1 : 3 2 : 7 11852 2 : : 2 4 1853 1 1 1 3 : 6 1854. 2 2 3 1 4 12 1855-6 ; 0 11857 : 1 F . 1 11858 1 2 2 2 6 E 1 14 1859 ; F 2 2 3 2 2 11 11860 3 1 5 4 i 1 1 3 3 1 iL 1 21 1861 2 1 : : Peay tall : : 2 1 Fi 1862 : : E : : : : 6 3 : 5 Sopa ale | Total 19 13 27 25 10 9 12 19 30 22 5 ae oe WOES, Xe 93 ye * ae 178 ON THE PERIODICITY OF THE AURORA BOREALIS. VI. AURORAS OBSERVED AT PROVIDENCE, R. I, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. | Noy. Dec. Total 1832 5 5 a 1 ° 1 1835 1 : - j . 2 Baia 1836 ° 6 1 1 - 2 2 - : ; 5 6 1837 1 Bi all we 5 oy 2 : 2 1 “. 1 di 1838 : 1 ; il 1 1 s 1 2 1 1 3) 1839 3 5 1 & 2 . = 5 3 : ‘ 9 1840 1 1 a: 1 1 1 2 . 2 - 8 1841 : 2 1 1 1 1 6 1842 1 5 5 - = : : 1 1845 5 1 1 5 1 : 3 1844 -* . 5 : 1 5 : 1 2 1845 1 1 : 5 3 2 2 1846 1 1 1 1 . : 1 ys z > 7 1847 ° . 1 1 1 1 2 : 2? 6 8 1848 5 4 1 1 1 - 1 6 2 2 2 14 1849 1? 2 1 : . = 3 2 2 1 : 9 1850 | *1 : 2 2 2 1 2 2 12 1851 5 2 - : 1 2 = 1 3 4 9 1852 2 1 1 4 1 2 1 1 pe 15 Was53 2}. =) Bae : 2 1 E : = : 3 1854 lie 3 1 1 1 7 18509 ; | ° . c 0 1856 5 eee 5 1 1 1857 ¥ ce : 1 : 1 1858 1 4 il 1 - 1 1 5 1859 1 . 1 ° 2 1 4 9 1860 1 1 1 . ; : > - . : A 3 Total 15 17 14 13 18 7 10 Ca ak: 21 14 3 160 VII. AURORAS OBSERVED AT BURLINGTON, VT., ARRANGED BY YEARS AND MONTHS. “Year Jan. Feb. Mar. | Apr. May |} June July ie Aug. | Sept. Oct. | Noy. Dec. Total 1852 i) 4 4 5 6 2 | 2 2 3 2 2 it! 39° 1853 3 2 5 3 6 | 3 | 4 od eee 1 1 2 35 Total | 8 Boi ot) pelican ete el een late Sai ee 3 3 3 | ie VIII. AURORAS OBSERVED AT ST. MARTIN, CANADA, ARRANGED BY YEARS AND MONTHS. Year Jan. | Feb. Mar. Apr. May | June | July Aug. Sept. Oct. Noy Dee Total 1853 ee 1 4 4 2 ales 6 1 2 3 39 1854 a5 5 6 5) 5 2 de gael aS 8 2 3 50 Total Cael Otel ee 9 9 4 14, | 6 14 3 2 6 89 IX. “AURORAS OBSERVED AT WILMINGTON, DEL., ARRANGED BY YEARS AND MONTHS. Year Jan. | Feb. Mar. Apr. Ti May | June July Aug. j ‘Sept. 7 “Oct Nov. ‘Dec. Total | | 1827 A C : 1 3 2 6 1828 1 : - A 2 = 2 > 3 1829 1 1 “ < . s c - 1 3 1830 : : 3 5 3° 3 1 2 4 1 2 16 1831 2 1 1 1 1 1 4 : , 1 : : 12 1832 1 ; 1 : : : : 2 1 : 1 . 6 1833 1 A 1 Va linea 1 ; ; 1 : 1 7 | Total 6 1 4 if Fie | PR 6 Selelo 3 3 4 53 X. AURORAS OBSERVED AT NEWBERRY, VT., ARRANGED BY YEARS AND MONTHS. ON THE PERIODICITY OF THE AURORA BOREALIS. ay 9 Year Jan. Feb. Apr. May June July Aug. Sept. Oct. Total - 1830 1834 1835 1836 1837 1838 1839 "1840 1841 1842 1843 1844 1845 1846 1847 1848, 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 me He bos bo: + meee - CHM Rs oO WNW. » me poner. - - me boe © DODO Dee es Total 23 34 28 6 2 — I 1 3 .» mcoOho. -« Nore bo bo G CO- Doe pNwwrs,s- me bw. RR: . ae j— Nt Gh ete Pty 0 ee. al i a ANF ADOWOWOAWOFRPNPNODUANOH Se 14 3 11 oo bo 10 9 XI. AURORAS OBSERVED AT JENA, GERMANY, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. | Apr. May June July Aug. Sept. Oct. Noy. 1770 1771 1772 1777 1778 1779 1780 1781 1783 1784 1785 1786 1787 1788 1789 1790 | 1792 || 1793 1796 \/Totat 1 oH Re ee 1 - bore 10 1 CE ell el ee 3 14 eo. 15 a RR DDD DON WD OF Ob Oe io.2) rs ne "ato . is c, a ibe, Ae eh! Tk 180 ON THE PERIODICITY OF THE AURORA BO mi a auar Jan. Feb. uur. Apr. May. June | July Aug. Sept. Oct. j 1 1 5 1bse75I). 9 1777-8 | 2 1 3 Ww 1780 1781 1782 3 1783 1 1784-85 1 1 4 2 1 1 2 3 2 = a ao ao mee ee me. Go- Cre wr re wh. = me ewe ew wb Se Ol 1 or) a moe 1802-20. 1827-30 1831-36 1837 | 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 ‘Total 63 59 bo » De De WN. COM WH Cr . _ —_—— ee NN eRe. rPwoareren- bo- woncor- PP ioe =, wonwrfor- tne mw Or Ororbp | Goby rs ee - > 09 reo co- WNNAWNHMAOF PAN: fe: moo Od 2 Saitoh Our a Re roNw Ee oN. » We Kew. . _. www NEO POR RR ob wh br we Coe eS bo bo Co bo bo BPR OF RR ORR. KoOnwwrrwnwnNre-.- Do WOaRhD: ea ae aa Bee / Pwr wnT re we DO Dm OCH FO Poor: Ie: Fe pe NC Nall ale Rw NRF OWNWwWhr-: ee 67 46 | 72 | 66 | 97 | 62 | 86 | Gi |siR i Nw 12> i) XIII AURORAS OBSERVED AT ABO, FINLAND, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Noy. Dec. | Total 1749 1. . 1 2 1 1 1750 2 2 5 : 3 x News 9 1751 2 : 0 1 5 3 1 : 1752 a | 2 1 1 1: 3 5 il : 15 1753 1 1 3 1 5 1 : 10 W754 1 1 2 2 5 1 ae OS 1755 1 2 : : 1 4 il 1756 1 : 5 : 1757 1 1 2 1 1758 il 1 5 2 1 2 1759 3 1 1 2 2 1 1 il 1760 3 2 3 1 1 1 1761 1 2 +2 1 1 4 B} 2 2 1 15 1762. 3 5 2 3 4 5 1 20 Total 6) 14 14 14 1 0 1 6 24 21 8 7 TS) ON THE PERIODICITY OF THE AURORA BOREALIS. 181 XIV. AURORAS OBSERVED IN THE STATE OF NEW YORK, ARRANGED BY YEARS AND MONTHS. (tea: Jan. Feb. Mar. Apr. | May June July Aug. Sept. Oct Noy. Dec. Total 1826 4 5 5 5 2 0 5 2 1827 1 ; 2 } F 5 3 1 1 1 14 1828 3 2 2 2 3 1 2 6 3 1 Ve} 2d 1829 3 5 - 3 2 5 A 2 3 3 1 2 | 2a 1830 2 4 4 5) 10 a 5) 12 8 14 t 5 80 1831 3 4 16 | 6 2 8 11 1 1 3 : 1 55 1832 1 2 5 3 3 2 4 3 2 1 5 24 | 1833 1 . 2 3 4 2, 3 3 10 6 1 2 37 1834 3 2 6 2 1 : 2 2 1 8 2 6 35 1835 i) 3 2 1 : 2 2 2 7 1 4 il 30 1836 - 2 1 9 4 10 10 11 3 4 6 1 61 1837 4 2 6 6 3 3 5 5 8 2 i) de Bro) 1838 5 4 c 4 1 3 4 3 10 1 4 3 42 1859 9 2 5 a 8 2 2 6 6 5 3 1 57 1840 6 5 td 10 9 3 3 9 5) 6 5 5 73 1841 2 12 9 6 5 2 8 12 5 5 6 1 73 1842 3 3 2 6 6 3 6 i 3 2 4 2 39 1843 4 8 5 8 3 7 7 3 6 5 : E 56 1844 Lop ay 1 5 3 5 if 1 1 4 3 4 1 30 1845 3 3 4 3 1 . 3 5 2 2 1 1 24 1846 2 : 1 5 9 2 3 6 8 5 2 4 47 1847 2 1 9 7 3 1 3 3 3 2 8 4 46 1848 8 12 8 9 3 3 6 5 1 ai 6 5 73 1849 4 8 8 8 . 5 6 5 12 10 1 6 73 1850 1 7 9 5) 7 O. 9 14 Tony 8 4 6 90 1851 2 3 4 a 276 1 6 3 10 a i 5 53 Total 76 89 110 | 132 89 80 106 125 141 Wales 75 65 1205 XV. AURORAS OBSERVED AT GOTHAAB, GREENLAND, ARRANGED BY YEARS AND MONTHS. Year Jan. | Feb. | Mar. Apr. | May June July Aug. Sept. | Oct. Nov. Dec. Total 1841 : oe ee ] ee Bon |p en |) atOnn oe ae "1842 15 18 | ler 9 5 : Rew! 14 6 11 12 95 1843 12 LOW a6 4 | . 5 d 1 1 3 18 9 84 1844 11 Bat Dial adic : : 3 12 12 15 12 87 1845 12 13) | 9 De she Ws ° eh “ 11 10 8 9 74 1846 ll ite 9 Ht le 6 0 9 5 | 32 Total | 61 60 | 50 21 0 0 0 5) 58 | 45 71 64 430 XVI. AURORAS OBSERVED AT HAMMERFEST, NORWAY, ARRANGED BY YEARS AND MONTHS. Year Jan. Ben. Mas. 2 May June | July , Aug. Sept. Oct. Noy. Dee. Tota_| 1850 5 a =p wilt ake 3 j 1 1851 2 : pay © O° las 9 1852 3 2 C Be Whe 2 9 1855 2 2 1 iene. 1 1 7 1854 2 2 1 1 3 3 12 1855 1 6 3 4 8 1856 il 2 1 2 1 2 9 1857 2 6 J 1 3 1858 2 3 2 3 1 8 1859 1 3 1 2 5 12 1860 *2 1 1 2 2 8 IS6L 1 3 : : 5 Total 19 16 Ball er0 0 0 0 0 4 9 16 19 91 182 ON THE PERIODICITY OF THE AURORA BOREALIS. ‘ XVII. AURORAS OBSERVED AT KENDALL AND KESWICK, ENGL., ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. | Sept. Oct. Nov. | Dec. Total F 1786 : ; : 3 1 2 6 2 1 1 16 . 1787 3 i Ame Wee ote Pa Ra el lea 5 eae 1758 6 5 3 8 7 ieee 6 3 6 5 2 535 1789 1 4 4 3 : 1 9 5 7 10 1 45 1790 1 2 6 8 4 : . u 3 9 2 36 1791 1 1 5 4 2 1 : 6 7 7 3 Me | 1792 3 2 2 3 1 1 2 1 6 1 1 23 1793 3 3 4 3 : j ? 5 : ae | Total Tits 18 26 32 21 5 2 21 23 36 38 10 250 XVIII AURORAS OBSERVED IN GREAT BRITAIN, &c., ARRANGED BY YEARS AND MONTHS. Year -Jan. 1794 2 , eee ; Sail ee ; ; 2 1795 ; : ; : 3 ; : 2 1 ‘ 1796 : : ; : é ; : ’ ; : 1797 1 4 3 1 : : : ; ; 4 : 1 1798 : ; ; ; ; : : : , 1799 et lee g : : a idWek 1 ; 1800 : : ; : : : ; : 2 1 1801 2 is ; : : : : cof ite he 1 : ; 1802 : 1 1 : : : i 5 1 ; : 1 1803 ; : ae : ; : 1804 : : 1805 1 1806 /||1807 J : 1808 i 1 1809-13]. A : : : ; 2 i ae 1814 : 1 : : ; : 2 1815 : : : : : BEN a: : 1816 : : : ; : . 1 1817 : 1 : : : : j : : : 1818 ; ; : ; : : 2 ; 1819 , ; : : ; ; A Pid facaees 1 1820 1 1 : : : E : : : 2 : 1821 : ; ‘ ¥ : : ‘ ; : ‘i 1 1822-4 : : ; : : : 1825 ; 1826 1 : i oe a ee ‘ : 1827 2 1 : : : : 1 1828 ; 5 : 1829 ; 3 1830 2 ; 1831 7 3 1832 1 1833 i 3 1834 1 1 Total 21 19 23 12 3 2 1 3 35 23 21 22- | 185. Feb. Mar. | Apr. May June July Aug. Sept. | Oct. Noy. Dec. | Total _ ee — _ NF OCONNWNKF KF OCOWOKrFOCWhKADERWNOWOWDR te. Ee . us \pelcotet ls e Be Cre We © Oto me 6 i [o ¢) » We DWH. bo a a ia » OrRrRONWNW-. ON THE PERIODICITY OF THE AURORA BOREALIS. 183 XIX. AURORAS OBSERVED AT PLYMOUTH, ENGLAND, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Noy Dec. Total 1728 3 : 1 2 : 3 2 3 1 1 13 1729 2 ; 5 1 2 a > 1 1 1 8 1730 é 5 2 1 > 5 5 1 3 - : 7 1731 : : it c I 5 1 1 1 3 1 6 1752 1 1 7 0 d 0 : 5 5 3 c 2 1733 6 1 a il C 2 5 1 1 1 2 9 1734 5 : 0 2 : : 1 5 - 5 3 1735 : c - 3 c 1 5 1 : 2 1736 c 2 1 5 : 5 : : 2 2 4 5 11 1737 . 5 m 0 C c e 4 - ° 2 1 ) 1738 1 5 1 : : > : : 5 + - 6 1739 2 : 3 1 1 : 3 2 : ° if 1740 5 : 3 + c 1 5 - : 4 1741 é 3 2 1 5 2 2 2 : 7 1742 2 F 5 1 é é : 5 6 1743 1 : 1 1 1 : : { 1744 : 3 5 1 = - 1 2 1745 1 1 : : : ‘ 2 1746 5 1 2 : 1 “ 4 1747 2 : 5 il : : 2 5 1748 1 : : 9 2 1 : 1 3 Total 8 ii 23 12 6 1 8 8 10 15 13 9 120 XX. AURORAS OBSERVED AT MAKERSTOUN, SCOTLAND, ARRANGED BY YEARS AND MONTHS. Year ; Jan. Feb. Mar. Apr. May June July |" Aug. Sept. Oct. Noy. Dec. | Total 1843 1 1 4 2 : : 3 3 3 3 | 20 1844 | 2 3 i) 3 3 2 4 6 2 30 1845 11 6 11 4 1 2 4 3 2 47 1846 | - 2 1 2 : 2 4 4 1 1 Nef 1847 1 1 1 1 5 1 2 5 5) 1 18 1848 | : 3 4 2 2 : 1 a 5 rd HN OAS ies ae 10 2 2 < 5 3 2 Lipase | 26 Moree 220i S6er |e 28 [5-16 6 0 0 7 16 | 99 | 28 i jee XXI. AURORAS OBSERVED AT DUNSE, N. BRITAIN, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Noy. Dec. Total 1838 5 3 4 3 : 6 2 4 1 2 3 Bile 1839 9 1 2 4 1 : 2 11 7 2 1 38 1840 5 5 2 4 5 S 3 oy 6 6 5 43 1841 6 3 4 4 2 : 3 3 3 7 fl 42 1842 2 2 A : : 1 < 3 - 1 3 9 1843 2 1 1 1 = 2 > 3 : : 10 1844 1 : 2 c 2 - 1 3 4 2 13 1845 1 2 5 1 1 2 1 1 1 10 1846 : 1 : a! : 1 2 7 4 1 ‘ 16 1847 2 2 3 1 5 : > 1 5) 6 6 4 30 | Total 33 20 18 18 3 0 2 14 43 34 30 23 238 7 ON THE PERIODICITY OF THE AURORA BOREALIS. July ‘Aug. Jan Feb. Mar. Apr May June Sept. Oct. Noy. Dec. Z : © S 4 9 4 3 2 , 5 3 4 : 2 1 5 3 5) 2 6 4 3 5 1 : ; 3 1 4 4 2 6 6 il 3 - 5 - 2 2 2 1 7 6 2 | 22 3 . : 2 3 4 bil 4 2 5 5 13 5 5 é 4 4 7 4 5 TG 8 11 1 = : : : 7 4 : 1 wind 1 6 1 : 5 2 3 3 3 : 2 3 1 - : 6 1 2 3 : : : 3 3 1 : 8 aa 4 Bos 2 1 5 6 2 T 4 10 4 5 | 4 4 1 6 : . 5 4 5 4 5 5 7 6 5 2 1 5 3 6 4 5 3 3 6 1 1 5 6 3 5 2 1 + 1 : , 3 2 2 4 1 8 7 6 : 11 2 4 & if 3 2 2 5 5 : = lor) oa al as] Su 55 Year Jan. Feb. | Mar. | Apr. | May June July Aug. | Sept. Oct. Noy. Dec. 1840 2 1 1 c 1 2 2 3 1841 : 4 it : d 3 4 3 1842 3 : : 0 : 3 2 5 2 1843 2 2 3 5 - 2 3 2 4 1844 2 1 1 : 5 3 1845 4 3 3 1 4 3 2 4 1846 2 3 1 5 2 6 2 5 1847 4 3 3 i i 3 1 2 3848 2 4 | ln oe = 1 4 3 1849 1 . 2 2 3 3 1850 3 1 3 5 2 3 4 5) 1851 4 2 i pe 3 5 5 3 A 2 5 Tc ia a ie? ee Pl ee 0 0 0 17 28 34 37 XXIV. AURORAS OBSERVED AT STOCKHOLM, SWEDEN, ARRANGED BY YEARS AND MONTHS. Year | Jan. | Feb. | Mar. Apr. | May | June July Aug. | Sept. Oct. | Noy. | . Dec. Total 1783 5 ie ai 1 1 ; : 1 2 ? aioe 6 isa |—1 1 ; ; i : : 2 2 1 hea 8 7 1785 1 1 1 3 2 : 5 4 2 2 19 1786 : 3 g. 1 Abd: 1 2 6 5 B 4 47 1787 | 10 5 8 8 2 1 4 5 6 6 55 1788 4 3 7 6 a 3 9 11 5 4 53 1789 3 5 elles t . 9 6 4 10 4 57 1790 5 9 13 9 6 ; 3 5 5 4 59 1791 3 { 2 2 : 1 7 2 1 1 19 1792 oe ere 3 Sic aoa t ey ere 2 > la9 : | ou o or for} Total whe | ot = ow =) So is (r=) i ‘x ist) o (Jy) ms ON THE PERIODICITY OF THE AURORA BOREALIS. 185 XXV. AURORAS OBSERVED AT ST. PETERSBURG, RUSSIA, ARRANGED BY YEARS AND MONTHS. Year Jan. | Feb. | Mar. | Apr. May June July | Aug. Sept. Oct. | Noy. Dec. | Total | 1726 2 we Ge ul 5 ie al We 2 || 1727 eS eae BO ; ; , he 2 2 : 1 11 || 1728 1 Ae Se ie ea) 1 : ed 2 6 2 1 25 1729 : : ’ 1 : : 1 3 ) 1 6 1730 | 1 1 7 6 1 3 aS at 1 | 85 1731 2 : 5 1 1 Ty ere ee 2 18 1732} 3 2 i. ¥ 1 ne a 12 1733 3” Oe i : ag) Pe 2 1 6 1734 met pl 4 | 2 Call ee Vinee 13 1735 See sl ies Ht | : 1 1 te 7 1736 ie | 2 1 1 2 he 1 9 1737 : : 1 3 : . E 3 2 Th 4 ; 10 1738 E 1 ; : : : rile ol 2 7s a 2 7 1739 Te glee) 7 1 1 : mee 5 : ; 19 1740 3 : 4 . | 3 1 3 | 13 1741 3 3 2 4 5 4 2 Se DE 1742 1 : 7 8 2 3 4 2 Py tere 1743 2 i, Hee Ce ee : ; i 1 ; 1 ee or 1744 : tt a : ; F : ; : : : ie wl at 1745 : ie ; : 1 ‘ ; : : ; : 1 1746 1 | 5 3 10 1747 ley pe : : : 1 6 1748 : esi tee cal : 1 : : ee ae 2 1749 f ze ee, Vee : ; 3 : ; 1 1 1750 Z BY Bee Gli ke 1 : ; : || ee 1 : 4 1751 1 Ea Mil) Bee : 1 F f 2 ; : 1 5 1752 31a NUE Blea: Bs 1 ’ 1 4 ame | 1 1 12 ss ee ; Plt ae : - : : : oF 0 1755 : 1 et eee . ; ; : : ; : 1 1756 ty eran ee Bas : A ee de |e : ; 1 1757 iM eee oe Secale oe : ; : ‘ : ; 1 1758 30am ade Me : ; : i h We 1 1759 ae Dee 1 2 : : Soot ee S| ay || Mg 8 6 1760 { eye": 6 : a | 2 ; . el ae 10 1761 eee : : ‘ 1 4 2 iP Al 11 1762 Sema cous 3 4 1 | 43) 3 2 3 4 25 1763 el ys Lis 1 1 1 1 : 7 1764 wad: 2 1 1 1 : 1 1 12 1765 1 if Pe a! 1 1 8 1766 i 4 ; 7 || : 0 1767 Mie EOe TP ae 2 : 4 1768 Fa Se Ble xc ; ¢ a) Nae i ; . 3 1769 , _ od AIP de ; Pee iets Ae) ihe ail 4 3 2 10 1770. | ee 3 3 , , : Ot Me ie aie 2; 13 1771 1 3 7 1 2 1 1 4 Ame Nao 1 27 GG 3 ae hes 7 4 , 2 2 2 22 . Wwe meee Ooh oO : + Rt. ee BN N ON TER | ll oe Bk 9 tative lg ae SWE WRN WO WN NAO RR WCONK OROHE DE Oe or eo . te Pe Oin: scan eo mom ow ew ST. PETERSBURG, Continued. » Scots mow. ; ON THE PERIODICITY OF THE AURORA Bi 2° We . he me oe oo ce . Oils @ Com + es 6 WOO me © e NESE NWOANOAN DS ORKEALIS. em Orbs bo Ordos ee. 2 "HW: Noe WN OO CO CTR s Je O's B fel .e) a) eo) 1s) (Oke On =tigt & 6.6 ROR es 6 6 eo f f i ON THE PERIODICITY OF THE AURORA BOREALIS. 187 ST. PETERSBURG, Continued. | Year | Jan. | Feb. Mar. | Apr. May June July Aug. Sept. Oct. ; 1847 a oe ; é s : ; 2 1 Sag 3 4 | | 1848 1 . ; : 2 : ; : : : 1 ; 2 | 1s49 = ae : Fe 2 5 : ; : 1 | ter |. 2 3 Fehr : : 4 : J 1 1 4 j 1851 1 ; : : : : : : 3 1 : 1 6 1852 iy hie 1 1 : 3 Pe 10 Igpp=4- | sa} : : : : : 5 0 soe | 91 2 ; : : 2 1 , 1 7 deo)! |. . ae ire) ; , : , 1 1 ‘ ; 4 3 sige : : : 1 : : ’ : ; : 2 3 | 1858 3 ib al (A, 3 : 5 12 "1859 Me ae te: a. le : é 2 4 4 1 15 | | 1860 OW ae 7 5 1 2 5 5 : 1 28 | 1861 ae ee 2 1 : : : : ‘ : : 3 |_12 || | Total TOMNIRLOOMab7ONn \pkoze) |) 42 13 15 62 |145 | 146 83 791086 || | ~ XXVI. AURORAS OBSERVED AT BRUSSELS, BELGIUM, ARRANGED BY YEARS AND MONTHS. | [es Jan. Feb. Mar. Apr. May | June July Aug. Sept. Oct Noy. Dee. Total risen | 4 1 4 2 af (23a qe a 1 3 2 : 2 22 1779 1 1 1 2 2 : 2 : : 3 2 3 ‘17 WSs |||) A : : : : : : 2 2 : pe 4 Uisst) |. , 5 4 2 : : 6 1784 | 2 : ; : ; el : 0 Weepe) || | : 1 2 : 2 oe eel 2 10 ise, | 1 1 1 5 12 1 3 6 «| 2 . 2 34 en |) (1 5 5 3 2 7 5 2 2 1 : 33 1788 5 1 il ba ee 5 5 1 4 2 1 18 || 1789 ‘ ; Re |) are 4 1 6 3 2 1 : 24 1790 : : ; : ; : 0 1791 1 : = A 2 1 1 1 2 1 4 13 TL ee . : : 3 : 1 : dH ae : 6 |] 1833 : : : : ; é : 4 1 i 1 2 || 1834 1 : : : : 1 . ; d : : | ! 1835 ; ? . : : : ; ee 1 |i || 1836 , : : ; ; : IMC i : 1 : 1 || 1837 Z 1 : : : OP agora oe 1 es hey 3 | 1838 le od ly oe : wae Pe ; f : : 1 | 1839 (2) el pa : : Tateal bs : : 1 i | 4 | 1840 Lhe it 2 1 1 2 4 | 1841 eee oct laces | ; 1 5 | 1842 ite 1 imei 3 1843 | aa eer : : ; 4 || 1846 ; : at j | t 2 J 2 1847 : ; ie} 1 1 1 1 5 1848 nek 2 ; 2 1849 ; 2 : Ay: : : ‘ d ; 1 1 jor 1851 Py |e Oh ae ae hes | ees : 1 eT Nee es | Total en A a Tee a eT ee ee ee ee 188 ON THE PERIODICITY OF THE AURORA BOREALIS. XXVII. AURORAS OBSERVED AT UPSAL, SWEDEN, ARRANGED BY YEARS AND MONTHS. Sept. Year Jan Feb. Mar. Apr. May June July Aug. Oct. Noy. Dec Total 1716 : A 1 dl ipeae ; ioe : 1 1718 1 2 1 1 2 2 9 1720 1 ; : : 1 1723 ; 1 : > | aml 1724 i 1 1 i 2 s lag 1725 1 il : 1 1 1 5 1726 1 : 1 1 1 3 7 1727 2 2 2 : é , : : 2 8 1728 2 7 3 2 : 3 3 4 2 1 27 1729 1 5 5 4 1 : ; 3 3 6 3 31 1730 4 5 3 : 1 1 3 15 10 10 : 52 1731 Oe 1" 43 5 u 5 4 6 5 6 36 1732 WO |p 11 6 : 1 3 1 4 42 1736 eee : ‘ fi 2 14 1737 4 1 ; eas ee ; d : ; 5 1739 1 2 6 Ro BD . 5 8 7 7 1 45 1740 3 5 8 1 1 3 4 6 3 3 37 1741 6 7 9 7 1 “alt 9 16 if 10 83 1742 1 7 7 2 : : oats 8 10 2 2 46 1743 2 5 7 6 1 : 5 6 8 4 B} 47 1744 1 2 3 1 2 2 1 1 2 15 1745 3 7 : . : 2 1 2 5 20 1746 5 10 5 ie 1 6 14 3.< 4 49 1747 6 1 8 By +4 4 4 4 2 36 1748 2 4 8 , 4 7 Be 6 6 40 1749 ON ee 10 4 1 3 5 2 3 32 1750 2 [es 6 2 5 2 2 2 1 27 1751 : 1 1 : ; Sale 4 8 22 Wd) |. 8 pam et : 2m 4 4 40 a 3 10 8 2 5 ; 1 5 34 eee) 2 5 2 1 2 3 1 17 Wip5, || 2 ; : 1 3 2 1 9 1756 | 4 2 1 2 ‘ 6 3 ; : 15 1759 | : 6 4 | : 5 11 2 9 12 51 TACOm WG 9 5 Cen ee 1 3 ; 8 7 4 50 1761 | 9 ll 4 8 1 3 5 2 4 1 48 1762 ee 1 ' : : : : : era 12 Total 85/181 | 152 75 vi 2 4 72).| L260 46) ios 109 {1018 XXVIII. AURORAS OBSERVED AT TORONTO, CANADA, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. | May June July Aug. | Sept. Oct. Nov Dec Total 1848 8 14 15 18 11 6 9 6 7 15 15 12 132 1849 8 17 Tal 20 11 11 12 8 12 12 13 4 139 1850 3 3 3 6 5 3 5 4 | 5 9 3 1 50 dl 85 1 ra Meee 7 2 8 4 5 ai 9 7 5 9 r 68 Total Pik |) Bie 3b4 46 39 24 31 25 33 43 B4 26 389 ON THE PERIODICITY OF THE AURORA BOREALIS. 189 XXIX. AURORAS OBSERVED AT BERLIN, PRUSSIA, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. | Mar. Apr. May June July Aug. Sept. Oct. Noy. Dec. Total 7] 1707 £ 1 0 7 5 2 1 4 1716 ' 1 2 : c : A 3 1717 1 aA ad : Is" fp 4 1718 : - en 1 are lle ac . 3 1719 3 1 : 5 oe || 1 1 3 1720 1 1 , : 2 * | 4 1721 1 1 La | | ° - an 3 1722 . : sh) Fs | 2 2 4 1723 : 1 1 : ; els 2 1725 : 1 1 1 > | 2 5) 1726 S > : 5 5 0 1 1 1727 : 2 1 : : hee 1 : 4 1728 1 d 1 1 1 1 LU ie al 1 2 10 1729 : ; d : - ; n wll est 2 1 1 6 1730 ; 1 1 1 1 4 1 3 3 11 1751 1 : : 5 2 2 . 1 5 4 7 1732 ¢ 2 2 1 : 1 2 3 1 12 1733 2 6 2 1 1 1 2 1 2 10 1734 1 1 1 1 eC 1 0 é 5) 1735 2 5 2 1 xe - 3 5 1768 “ : : 5 - ; 1 1 1769 é 2 2 : > : 1 1 - 2 1770 2 5 5 5 1 5 ; 1 C Q 19 1771 4. 4 1 3 5 1 1 . C 3 2 24 1772 2 1 aa 3 - 5 : 1 1 F 2 1 15 1773 4 4 4 5 4 2 5 1 : 3 2 20 1774 5 3 6 4 : 5 2 ; 12 1775 : 5 ci : = 1 1 1776 2 : é : : 2 1 1 : 4 wees : 1 3 3 a 1 1 al 2 12 1778 , A Sa ees : 1 2 1 ‘ 10 1779 d 4 AN Vt 8 ; i 1 2 ; 16 1780 5 F : 1 5 2 c 1 2 1781 6 1 3 : 5 2 : 3 1 2 15 1782 1 1 3 a 1 1 é 1 4 5 12 1783 é A Zit eo 2 - : 2 1 12 1784 ct ° 2 : 1 2 1 - 6 1785 = < c c : A 2 1 3 1786 3 2 6 10 2 ' 1 . : 24 1787 1 : . 3 2 1 4 3 11 1788 2 Sam] 2 : c 3 2 1789 ‘ 2 lineal : 2 Total PAW | Bit Bs) 48 39 2 10 10 22 45 29 13 331 Year Jan. Feb. | Mar. 1779 1 3 2 1780 S 1 1 1781 E 1 3 1782 3 2 . 1783 3 : 3 1784 5 a S 1786 5 E : 1789 . . 2 1804 S 5 1817 5 1 2 1831 1 0 3 2 9 13 Total ‘© (ek - Gein as ON THE PERIODICITY OF THE AURORA BOREALIS. XXX. AURORAS OBSERVED AT PARIS, FRANCE, ARRANGED BY YEARS AND MONTHS. Jan. Feb. Mar : 1 E 1 1 1 3 s 1 E 2 1 2 1 1 : - ; ; 1 . if . i . 1 Se |: 1a 1 1 4 5 12 July Aug. Sept. a eee NS 1 3 2 2 1 1 1 3 1 1 ° 1 - 1 : an 2 : 1 : 1 : . 2 2 1 6 10 15 = il 5 . a . 3 2 if 2 : H 1 s i ~ 3 1 . 2 . ‘ * E “ Lf - 3 “OF c : ie | 4 A 0 - 5 1 1 5 20 5 ‘ iy - : Jah : ps | 6 > 1 1 4 i A : Oe 1 4 é (Bao) A 1 SF | 1 . 3 if é 3 . 1 ¢ 1 8] 12 4 103, May | _ June i July Aug. Sept. 2 1 3 1 1 1 4 5 1 uf 1 4 1 1 1 . . = 2 . | . . tag hare so 2 1 ° : 3 di . : = ay 1 = . eel fer | 1 2 4 1 1 aie 1 2 4 1 | Peal see| 1782 | 1 1 1 ‘ : 1 3 mt Whey 1783 1 3 3 : k pe ee 1 | 13 1784 : 2 : 1 : 1, 1 5 1785 | : : Z : 2 Oe | 1786 | i 2 1 1 1 1 2 ; 3 site) «T 1 1 2 1 1 1? 1 2 11 1788 1 3 1 ie la 1 8 1789 : 1 1 : 1 1 1 5 1790-1 | : : : 0 1792 1 1 | 2 | 1793 bet | eee : : 1 1 | 2 |I ‘ 1794 | 1 oe Hi r "i 1795 : : A 4 | 1796 3 0 1797 ; 5 3 1798 1 z 1 1799 E 1 1 2 1800-2 | : 0 1803 1 1 1804 : ; 1 : ae i ; ; : 1 | 1805 : : : : : : s ‘ 1 : ty Total 8 13 26 eae fib 6 9 11 27 20 ll 5 | 175 XXXII. AURORAS OBSERVED AT FRANEKER, HOLLAND, ARRANGED BY YEARS AND MONTHS. . Year | Jan. Feb. | Mar. Apr. May June July Aug. Sept. | Oct. | Nov. Dec Total 1771 a 1 1 . 2 : 1 ; 2 2) |) Sa eo 1772 : 1 3 2 : 1 : 2 5 7 ae 14 1773 1 : 4 2 ‘ il 2 3 7 1 Pa EOE: 1774 2 ; 10 1 5 ; 2 5 2 3 3 Lb | (84 1775 8 3 8 7 3 2 F 6 : Viulaeesl 39 1776 2 2 1 2 1 1 1 7 2 ry lana 21 1777 1 2 6 5 3 1 3 3 5 7 ii teas) 36 1778 4 1 4 : 1 3 1 1 3 2 3 2 22 1779 2 4 3 4 1 : 4 2 3 ed ees a7 1786 : 1 ; : . 2 1 ao "yl lane 1781 1 ; f : here ie.| Total 20 15 41 23 16 6 8 15 30 30 13 1 See 1 ; 1 1 : : 1 3 1 : 5 ; : : E 1 A 1 ; 3 , 1 1 : : ; i | 7 3 2 11 PC — Cie — eee ee ee Oe ee . S May | June July \< 1727 5 1 8 5 ; ; 2 1728 1 fi il 2 1 1 : 1 @ 1730 ‘ i 6 1 q -j . 1 : 1731 : a : : : £ aa 1 1732 ‘ 1 1 5 1 i . ; 1733 : i ‘ ; 1 : F 2 1734 p 2 1 ; d 3 : 1735 s 2 1 4 ; : : i . 1736 : ; 1 : al 2 : 2 ; 1737 2 i : | : 2 : 3 1738 : 1 is 1 1 5 ; 1739 5 ‘i 2 : : ? : 1741 1 k x : : - 2 1743 : : 1 - 5 P 4 1744 : : s y : ; 1 1745 E ‘ 4 i : i 2 1747 m ' c P ; 1 1 4 1748 ¢ 3 : . : ‘ f 1 1749 : 7 : : A 2 2 1 1750 : 2 : 1 : ; 2 : , 1751 : ; 7 ; : 1 . 5 Total 4 9 21 5 3 6 Ta en 12 ees i pion 7b.) 8) a ee ie HONwWHe Hon ome 3 z DAaowonor 16 bet > OD et OO DO CO OO ON THE PERIODICITY OF THE AURORA BOREALIS. 193 XXXVI. AURORAS OBSERVED IN NEWFOUNDLAND, ARRANGED BY YEARS AND MONTHS. | Year | Jan. Feb. Mar Apr. | May June July | Aug. Sept. Oct. Noy. Dec. Total || 1849 4 8 2 LO wa Bil 4 4 5 4 3 2 48 || 1850 1 6 6 Ms) 8 3 8 | 6 6 9 : 3 | 52 || 1851 4 6 | 6 bh 1 1 ee 6 2} 5 51 Wiest |g || 20 | 14 | 16 | 1 Te Re ees ed a XXXVIIL AURORAS OBSERVED AT QUEBEC, CANADA, ARRANGED BY YEARS AND MONTHS. Year Jan. . Feb. ar. ara 7 | na June July | ra Sept. Oct. Noy. Dec. Total 1348 ; 8 5 ees mee 1 1 3 3 i 6 3 52 1849 3 12 3 7 1 5 3 1 4 4 2 é 45 1850 ‘ Dele a3 3 1 3 6 6 oA aad 5 3 44 1851 3 Ba 38 3 1 1 Saal ok. nhl 2 3 1 28 Total 6 | 25 | 14 24 Fi 10 13 | 10 \ sao os 13 (fm pl) | XXXVHUI. AURORAS OBSERVED AT LONDON, CANADA, ARRANGED BY YEARS AND MONTHS. Year Jan. | Feb. | Mar. | Apr. | May | June July | Aug. | Sept. ] Oct. Nov Dec. Total || 1848 5 igi [ae] 7 Der ul. 3 2 tlle 2 3 3 laos || 1849 : 3 5 4 1 2 3 2 1 7) 35 é 26 || 1850 1 Sele d 5 3 : 3 2 Semel ro BE 30 1351 LR ae bay 2 1 Se Viv ate eeu 2 18 Pear) el wm.) te | 6 | 3 10. 3) Ul ore es 3 elon XXXIX. AURORAS OBSERVED AT SPYDBERG, &., NORWAY, ARRANGED BY YEARS AND MONTHS Year | Jan. Feb. | Mar. Apr. May June July Aug. Sept. Oct. Noy. Dee. Total 1784 1 a 3 1 : 1: 5 ea er 18 1785 1 4 | 3 ; il 3 3 1 CTS 12 HESG:.)| = at 6 1 ; 1 8 el eae 24 1787 | 6 eae Maas : es 5 4 : i eg TN} a a a I 6 De WO) ae UG sy OD Sl |e 6 81 ) XL. AURORAS OBSERVED AT SAGAN, ARRANGED BY YEARS AND MONTHS. | Year | Jan. Feb. Mar. Apr. May June | July Aug. | k Sept. Oct. Noy. Dec. Total | Sa : 1 1 1 3 3 1 11 || 1782 il 3 F : 1 2 4 Z || 1783 | 4 2 } 1 ? 4 13 \| 1784 | 2 ay 4 5 1 1 8 eitea || : i ay extn: : 1 3 ; 5 so.) ‘1 1 5 13 1 : 1 6 = ike: 28 se.) 2 1 4 5 1 é 2 2 9 se i & 33 || 1788 4 5 2 6 1 4 7 if bie) || ol 42 | 1789 4 1 5 4 1 3 3 1 aie 32 |} 1790 | 4 4 Te eae 1 3 | 8 1 alan |=! 24 1791 5 2 1 1 oats he alee 1 2 Peal © tt 15 | 1792 3 : 3 BRIE 1 ; : 6 2 1 22 | Total | 25 ; 14 | 34 | 40 8 2 3 8 | 22 | 39 | 81.) lem XLI. AURORAS OBSERVED IN SCANDINAVIA, &c., ARRANGED BY YEARS AND MONTHS. \| Year Jan. | Feb. | Mar. | ron May June July Aug. Sept. Oct. Noy. Dec. Total 1837 3 | é ; 8 12 3 23 ||. 1838 17 6 7 ‘ : 4 16 17 20 25 | 108 1839 22 | 24 | 24 11 : 4 12 24 15 13 | 149 || 18.10 lear se 7 ; | : : Soles ; 8 Total | 40 | 30 | 38 | 1 Gein iz 0 0 4. 428s poaie [ar | aie «288 VOL. X. 25 % Dec. 1 1 1 1 1 4 l Total 26 16 20 194 ON THE PERIODICITY OF THE AURORA BOREALIS. XLII. AURORAS OBSERVED AT MANNHEIM, GERMANY, ARRANGED BY YEARS AND MONTHS. Year Jan. | Feb Mar. | Apr. May June July Aug. Sept. Oct. Nov. 1781 1 3 6 tly ee : 2 1 2 2 3 1 1782 4 : 2 : 2 2 1 : 4 1 : 1783 1 a 2 7 D ; 1 i Ba : 2 1784 F ‘ 3 = F : 2 : 22 . 1 1785 ; 3 : 2 1 i 1 1 1 Dan 1786 1 5 2 3 F 1 ‘ Y 3 5 2 1787 4 1 rf 5 1 1 3 3 5 3 5 1788 2 2 3 1 2 ‘ PA 4 4 2 1 1789 1 2 3 1 1 } 3 : 1 ; 2 1790 2 1 2 6 i 1 1 1 3 1 1791 2 2 1 1 1 1 2 1 1 1792 : 2 2 a ee . a) ® ial) 860 Oe es) Be Ges we a YE 3] BES) Ss: aes 10 216 XL. AURORAS OBSERVED AT COPENHAGEN, DENMARK, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb, Mar. Apr. May June | _ duly Aug. Sept. | Oct. Nov. Dec. x Total 1782 yan | 1 1 [ey 1 1 11 1783 . eye) a Z a | 1 2 | 1 : 11 1784 1 a 1 1 : 3 1785 : 5 - 1 A - 1 2" 1786 3 1 ‘ 3 1 1 1 1 1 ; 9 1787 1 2 So es 1 10 1788 2 1 a fl Copal : ee ee : ’ : 2 Total | 1 ee: ee ee 1 4 | 5 2 2 48 XLIV. AURORAS OBSERVED IN HOLLAND, ARRANGED BY YEARS AND MONTHS. Jan. Feb. Mar. Apr. May June | July | Aug. ij “Rept. | Oct Nov. Dec. Total. Total 49 47 92 G3 MON 32 Sy 59 Th ee 47 | (34 aso XLV. AURORAS OBSERVED AT RATISBON, GERMANY, ARRANGED BY YEARS AND MONTHS. Year. Jan. Feb. Mar. Apr. May. | June. | July. Aug. Sept. Oct. Nov. Dec. Total 1781 1 1 1 1 3 ae) ee : 5 8 1782 3 1 . ‘ é 5 | il 1 is 3 1783 see lh ae 2 1 : 1? SN ae 1 8 1784 Ee ae 1? : 1 : | 3 1786 oo ane 3 : ; ; Taare A Sas 4 1787 : 2 1 2 ; : ey vie 6 2 14 1788 1 : 2 1 : 1 : | 1 ; 6 1789 é 2 1 3 3 5 . 6 1790 ; 1 A as 1 1791 5 ul A . J 6 3 : 5 ] Total 1 3 9 9 6 7 2 4 2 8 3 0) 54 XLVI. AURORAS OBSERVED AT PRAGUE, AUSTRIA, ARRANGED BY YEARS AND MONTHS. Year. Jan. Feb. Mar. Apr. May. | June. July. Aug.- [ Sept. Oct. Nov. Dec. Total. 1782 1 2 1 7: Pa Si : es Fs 2 : 5 1783 : 1 4 2 | 2 1 1 Neal 12 1784 1 é 2 - 2 1 1 F 1 2 4 1786 1 : 2 7) 1 - 1 » 1 e | 8 1787 2 2 ; 1 1 : 1 4 We 13 1790 1 j , 2 - 1 s - : : 4 1791 ‘ i 3 , : . 5 ; ] Pei : ] Total 6, 4 Ell atooa eal 2 3 al ae 5 lel 47 SSS Sooo eee ua ON THE PERIODICITY OF THE AURORA BOREALIS. | 195 GENERAL CATALOGUE OF AURORAS ARRANGED BY YEARS AND MONTHS. . } Feb. Mar. | Apr. May | June } July Aug. | Sept. | Oct. | Noy. Dec. Total * | | 10 9 4 2 5) 3 5 4 13 168 > : : Weegee : é . : 1 - | £ : 1 C | ‘ 1 1 ‘ | 1 1 : | ae ee : _ 1 : Tt 1 a | 1 1 : ° 1 - - ‘ “ A : 1 ¢ : - a 1 1 : ‘ : 1 : 1 2 1 : : se | : . 1 d 1 : 1 3 : : : aes ; : : : 3 1 - 3 - : 2 : 2 5 - C : 5 1 - : 1 2 - 5 . 1 1 : 1 3 S > ; 5 1 : : : : i 1 i : 1 : 4 k 1 ‘ : ; 1 , 5 ‘ : : : 1 1 ; : < 1 1 : : : ‘ : 1 E : : 1 : : - ‘ 1 - = 1 = 1 1 1 2 - 2 1 : - - ¢ : : 5 1 ase ‘ 1 é 1 : . 2 | : : : 1 9 1 ieee 1 3 : | eat lia : 2 1 : ee a 3 1 ‘ c 1 - 5 2 | . 1 . 1 . © 2 | - . : c ° 1 c < . 2 5 1 2 - a : 1 2 | 1 : 1 < ‘ : 2 ae 2 ; : : : ‘ : : 4 eae . é . : : : 1 oe : : , : : 2 1 é ‘ 1 1 2 . 5 * ‘ : : r £ 1 1 1 5 1 - : : - 2 : 2 1 S 3 * The total number of the year sometimes exceeds the sum of those placed in the monthly columns because auroras were observed when the month was not mentioned, but the year only. ON THE PERIODICITY OF THE AUROR GENERAL CATALOGUE OF AUROERAS. Continued. NOR al coll Mel ell <0 lle C2 = + 8 ee eb - DOM Ne « e lor} § Si , Pe POW RERUN ORWNI — a. ON THE PERIODICITY OF THE AURORA BOREALIS, GENERAL CATALOGUE OF AURORAS. Continued. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Noy. | 1? SOP BR ENN WW HE RENN NHN NRF EP RNB RP ENE NER ee Ree ~ NOR RP WOR OMe Hae — he 198 GENERAL CATALOGUE OF AURORAS. Continued. ON THE PERIODICITY OF THE AURORA BOREALIS. Year Jan. Feb. Mar. | Apr. May June F July Aug. Sept. Oct. Nov. ; Dec. Total 1718 (aero 6 1 2 1 1 4 4 2 6 29 1719 ee Fn : 3 5 10 6 36 1720 4 6 2 1 1 2 1 6 6 29 1721 3 5 3 : : : 4 5 3 ; 23 1722 8 7 5 1 1 1 ’ 9 12 7 5 56 1723 Bye tbe’ 90 9a 4 1 4 1 4 2 29 1724 4 2 3 1 2 5 3 2 3 4 29 ‘1725 5 5 1 3 Lent 5 7 Ns 33 1726 2 1 9 2 os ; 3 10 6 14 47 1727 7 6 14 4 Tq Ree : 5 9 15 15 12 88 1728 6 10 14 7 3 2 5 7 12 21 14 9 110 1729 9 10 7 7 8 2 1 1 8 8 6 4 71 1730 5 9 15 10 Ae al 5 6 17 18 20 9 | 119 1731 3 3 7 3 2 ; ; 7 9 13 9 ll 67 1732 13 14 18 14 3 2 3 5 14 20 14 7p |) ey 1733 3 3 6 4 5 : 3 5 3 8 5 6 | 51 1734 5 9 10 5 12 1 4 5 16 20 5 3 95 1735 3 5 9 9 > ; 5 9 7 5 7 59 1736 2 9 3 3 ie 2 5 12 18 gate 75 1737 18 8 7 8 2 : 5 8 6 6 7 75 1738 1 B) 4 2 3) (e- 1 .2 2 3 5 10 33 1739 5 6 15 8 3 1 7 13 i 8 3 76 1740 7 5 10 1 1 1 3 5 i 4 3 47 1741 9 10 13 11 ; 2 11 11 19 9 10 | 105 1742 3 8 12 10 1 : 8 10 12 4 SP 1743 5 5 11 8 1 i 1 5 ii 8 6 3 | 60 1744 1 2 6 2 4 2 2 1 9 29 1745 6 8 ; , 1 . : 2 3 2 5 27 1746 7 12 9 1 j 2 1 1 6 14 10 6 69 1747 8 5 9 5 i pi) ee 1 3 A) -9 1 10-| 49 1748 8 9 10 4 2 2 : 6 9 4 2 9 65 1749 2 9 11 12 3 1 1 1 6 6 3 3 58 1750 4 8 7 5 3 2 7 4 OG] = 5 4 51 1751 2 5 1 1 2 : 1 5 Ry rene! 8 34 1752 9 5 11 3 1 5 3 al ess 5 56 1753 ; 3 10 8 2 6 con Ae 5 35 1754 an ee Sanaa 1 3 3 1 ane 1755 ees eo Tt |) 8 2 1 11 1756 2 1 2 : 7 eas : : 15 1757 1 1 . ; A 1 re |e 2 : 9 1758 1 3 1 1 4 : ot : : 10 1759 re eG 5 3 > ; 5 13 3 9 12 56 1760 6 9 6 12 1 1 5 1 AG 8 4 62 1761 9 11 6 8 1 6 7 \ aes 5 2 58 1762 2 2 3 4 3 ; 5 Beale De 5 10 39 1763 : 1 4 2 : 1 2 1 2 2 p 15 1764 2 6 BP pare 1 3 1 2 pg aa) 4 1 25 1765 1 2 A ced 2 3 vies | Moe, 1 1 17 1766 | : em : 1 ON THE PERIODICITY OF THE AURORA BOREALIS. GENERAL CATALOGUE OF AURORAS. Continued. | Year Jan Feb. Mar | Apr. | May | June July Aug. "Sept. ~ Oct. Noy. Dec. Total | 1767 2 2 eae | mg 1 : : : 1 9 1768 2 2 : : Mae 1 2 Ds 3 2 3 16 1769 1 2 1 1 ae 8 4 1 3 ) 4 38 382 1770 2 8 7 7 PALA Uae 4 5 3 1 3 2 44 1771 5 7 9 4 Ton ee 2 5 6 8 7 3 65 1772 5 6 LOM eo é 2 4 1 5 10 4 3 59 1773 13 6 OFF 7 8 6 4 3 9 il 7 3 89 1774 3 2 16 9 11 6 8 12 13 1] 6 AD | OT ioe! |. 8 11 10 3 : 3 2 8 3 1 1 63 Hanon ho C, sin. 22 2 ¢,. The values of ¢, are found by dividing equation (4) by equation (3). SN: cos.2a2xt Se RNS 9 foe i *" SN, sn 2aazt VOL. x. 21 210 ON THE PERIODICITY OF THE AURORA BOREALIS. N, cos. 0 + WN, cos. x 30° + WN, cos. x 60° + NW; cos. x 90° + WN, cos. x 120° &e. = ]™ sin. O-F Wy sin. x 30° + WN, cos. x 60° + Ny cos. x 90° + MN, cos. x 120° &e.” Multiplying equation (3) by cos. 2 7 2 e, and equation (4) by sin. 2 m @ ¢, and then adding them, 8. m OC, =2cos.2a220e,S8 N, sin. 2Qaxt+2sn.2a2a0e, SN, cos. 2a xt, from which the values of C, may be obtained. If the series is supposed to converge so rapidly that the first four terms will give the number of auroras to a sufficiently close approximation, comparable with the accuracy of observation, the general formula becomes 9. VN=A-+ OQ sin. 27 (+ ¢) + CG, sin. 4 w (t+ cy) + O, sin. 6 wz (t+ 6). By this general formula I have calculated the mean annual curve (in this case alone carrying the computation to the seventh term), and also the particular curve for those places where a sufficient number of auroras had been observed to encourage such an undertaking. The number of auroras for each month has then been computed by the formula and that number compared with the number actually observed, and from the square of the differences the mean probable error has been obtained by the following formula : SAP 10.e= ,674VY m—1. If we differentiate equation (9), and make the differential equal to zero, we shall have an equation from which the days of maxima and minima of auroral display during the year may be computed. 11. C, cos. 2 7 (te) +2 OC, cos. 47 (¢-+- ec.) +3 C; cos 6 2 (t-++-¢3) = 0. The direct calculation of (¢) from this equation would be difficult. Knowing from the observations themselves nearly at what times these maxima and minima occur, by substituting empirical values for (¢) we arrive by this tentative process to the required result: viz.,the precise times and the values of the maxima and minima. In all the pre- ceding computations, whatever the number of auroras actually observed in the different months, they have been reduced to what they would have been if exactly one hundred auroras had been seen during the year, so that in each curve the value of A is 8.33+. ON THE PERIODICITY OF THE AURORA BOREALIS. PALL FORMULZ FOR THE MEAN ANNUAL CURVE, AT DIFFERENT PLACES. Jakobshayn, | V—=8.33 +- 10.40 sin. [2 7 #4-123° 2/]+1.13 sin. [47 #4+206° 7']4-1.41 sin. [6 7#+333° 24’). Gothaab, Newf’d, Quebec, Toronto, Newberry, Salem, Providence, Cambridge, Worcester, N. Haven, N. York, Abo,! Spydberg, Hammerfest, Christiania, Stockholm, St.Petersh’g, Upsal, Dunse, DMakerstoun, G. Britain, Berlin, Utrecht, &e. Franeker, Jena, Mannheim, Sagan, Brussels, Plymouth, Carlsruhe, Paris, Mtmorenci, Wittemberg, Italy, Gen. Curve, N=8.33 + 8.21 sin. [2 7#+110° 48’]4-1.54 sin. [4 7#+316° 67]+ .64sin.[6 w#1335° 10']. N=8.33-+ .33sin. [2 vt} 60° 17']+3.82 sin. [47 #4-336° 25] .71 sin. [67t+ 38° 37’). N=8.33-+ 45 sin. [2 at 57° 40']+3.72 sin. [4 v#+-315° 22'11.68 sin. [6 w#4+-331° 57’). N=8.33-+ 18sin.[2a¢+ 12° 8}42.13sin. [4a t4259° 57} .52 sin. [6 vt-4304° 51’. N=8.33-+ 3.52 sin. [2 7t+ 88° 42’]+-6.16 sin. [47 #4-826° 57’]+-1.96 sin. [6 wt 51°19]. N=8.33-+ 2.76 sin. [2 t+264° 47’J4-1.54 sin. [4 2 t4340° 57’ ]41.47 sin. [6 7 t-4-300° 55’). N=8.33-+ .62 sin. [2 wt4-127° 44’]+1-3.07 sin. [47t+-300° 0/]+-2.83 sin. [6zt+ 35° 59’]. N=8.33-+ 1.02 sin. [27 ¢+261° 5442.84 sin. [47t4339° 9/J411.28 sin. [6 2 t-252° 59’, N=8.33-- .72sin. [22¢4150° 11/]+3.86 sin. [4 7 t4+-320° 52] .95 sin. [6 wt4155° 34’]. V=833-4+ 99 sin. [2 7t4182°59/]41.02 sin. [4 4 312° 45" .57 sin. [6 2 ¢-+-196° 42’]. NV=8.33-4+ 1.84sin.[2vt}26L° 2/]42.29 sin. [47t4 924° 511 .54sin. [6 2 ¢-157° 11’). N=8.33-+ 5.40 sin. [207 ¢4114° 41']4-4.97 sin. [4 21 815° 42] .83 sin. [6 7 -1-356° 36’]. N=8.33 + 5.28 sin. [2 2 t4-111° 28’]+-6.61 sin. [4 w#+304° 27’}-+12.55 sin. [6 zt+345° 56’]. N=8.33 + 11.52 sin. [2 vé4+109° 2442.71 sin. [470 ¢4114° 11/J4-1.11 sin. [67 -1350° 37’]. N=8.33- 4.83 sin. [2 7 t--115° 41’]-4.99 sin. [47 t+-317° 28’]+- .76 sin. [6 z ¢-189° 287]. N=8.33-+ 3.68sin.[22t-+ 90° 4845.80 sin. [47t4+303° 9’]41.31 sin. [62¢-+180° 9’). N=8.33-+ 2.81 sin.[22¢-+ 95° 52’}45.99 sin. [4 7t4+308° 42/]+ .57 sin. [6 2 ¢1208° 24’). N=8.33-+ 5.41sin.[2at+119° 6']4-4.57 sin. [4 2t+821° 581 .86sin.[62t1296° 7’), N=8.33-+ 6.30 sin. [2 w#4140° 37/] 13.43 sin. [4 7 t+-313° 35']4-2.03 sin. [6 zt 91° 56’]. N=8.33 + 5.79 sin. [2 wt+4-102° 2’]4-4.47 sin. [4 7#+310° 30’]+-2.00 sin. [6 7 #+341° 35’]. N=8.33-+ 3.87 sin. [2 7t4125° 49']4-4.24 sin, [4.0 #4286° 574 .40 sin. [62¢-+ 73° 20’). N=8.33-+ 8.91 sin.[2at+ 48°17']45.44 sin. [407 t4288° 364 .59 sin. [67¢4305° 17’). N=8.334 2.29sin.[2at+351° 7']43.64 sin. [40t4281° 18']4-1.38 sin. [62 t1131° 6’}. N=833-+ 1.65sin.[2at+ 87°10']4-4.86 sin. [40¢-1311° 574 .30 sin. [6.2 ¢1-103° 58’}. N=8.33 + 2.09 sin. |2t+189° 8’]+-5.01 sin. [47 ¢4-305° 40’]+-1.26 sin. [6 7t++ 71° 35’). N=8.33-+ 1.17 sin. [2 7t4- 33° 2’]4-4.29 sin. [42#4+310° 52’]+1.55 sin. [6 7#+185° 44’]. N=8.33 + 3.91 sin. [2 7t4-101° 49’]-++5.69 sin. [47¢+284° 4’]+-1.03 sin. [6 w#4+241° 41]. N= 8.33 + 2.58 sin. [2 w t4+-312° 57’]+-2.77 sin. [4 v#4+217° 47] .98 sin. [6a7t+ 36° 1’). N=8.33 + 2.09 sin. [2 t+ 98° 33’]4-4.10 sin. [4 2 t+-303° 55’]-+-2.90 sin. [7 2 t+-253° 167]. N=8.33-+ 2.78 sin. [2 0t-4352°28/]45.11 sin. [47t4312° 59’]42.34 sin. [6 2 t4-214° 59”). N=8.33 + 2.09 sin. [2 2 t+-249° 47’]-+-3.47 sin. [4 7 ¢4+-272° 12’]+-1.46 sin. [6 w+ 71° 29’). N=833-- 24sin. [2 wt+300° 5']45.49 sin. [40¢1309° 54} .58sin. [6at-+ 30° 48"), N=8.33 + 3.28 sin. [2 2t+-119° 467]+-5.82 sin. [47 #+-333° 25'J+ .76 sin. [6 wt+-345° 52’). N=8.33-+ 197sin.[2at+ 68°37]4-4.85 sin. [47t4335° 481 3.24 sin. [6 22 #+-290° 35’). N=8.33-+ 3.03 sin. [2 a t4-109° 52!]-+-2.53 sin. [47t+309° 5'J+ .16sin. [67¢+213° 31] + .56sin. [8 7 ¢4+162° 45’]+- .27 sin. [10 w #820 38’). 1 This agrees exactly with the formula computed by Hiillstrom. Acta Soc. Sci. Fennice, II. 369. 212 ON THE PERIODICITY OF THE AURORA BOREALIS. As the ancient astronomers, by the matchless device of cycles and epicycles, were able to explain numerous irregularities in the apparent motions of the heavenly bodies, even when referred to the earth as the centre of motion, it is evident that the general formula above explained, when expanded into a sufficient number of terms, will accom- plish what the theory of cycles and epicycles has accomplished, since it is only the algebraical embodiment of that geometrical conception. We draw a line parallel to the zero line, and at a distance from it represented by A, the length of it. correspond- ing to one year. On this average line slides the axis of a circle, having a radius C, and turning on its axis once a year. A point in the circumference of this circle draws the curve which results from the two motions, 2 7 ¢, being the angular distance of this point from the direction of the average line on January 15. On the circumference of this cir- cle rests the axis of another, with a radius of (, the value of 4 ac, expressing the posi- tion for January 15 of the point on its circumfererice which describes the resultant curve. This circle turns on its axis twice a year. On the’circumference of this circle rests the axis of another circle, which turns round three times in a year. ‘C; and 67 ¢, have a similar meaning to that ascribed to the corresponding constants of the other terms. Generally, the most conspicuous characteristics of the annual curve are indicated by the values of the constants C, and 4 ¢,. Compared with @, or Cj, the value of (, is large and the angle 47 ¢, is such as to bring the maxima into spring and autumn and the minima into summer and winter. By comparing the values of C, and 4 a ¢, in the curves of different places, it will be seen whether there is any dependence in the times and the degrees of the semi-annual fluctuations on geographical position. If,at the same place, there is any change in the law of this fluctuation from century to century, it will ap- pear by comparing the values of CG, and 4 2 «, when computed from different series of observations made at the same place in different centuries. From the magnitude of G, especially when 2 7c, approximates to the value of 100°, the influence of longer and shorter daylight in summer and winter is discovered. This influence grows to such im- portance in very high latitudes that C, surpasses C, and the value of 2 a ¢, governs the times of maxima and minima. The increase of C, does not, however, progress so uni- formly with increase of latitude as to warrant the inference that the second term of the formula is expressive of nothing else than the influence of daylight. Superadded to the semi-annual periodicity of the aurora, there is an annual periodicity exclusive of that annual change introduced by the seasons. The fourth term of the formula may originate in imperfect or insufficient series of observations. A periodicity of four months is improbable in itself, and the co-efficient 6 7 ¢, is generally small, particularly in the mean curve, where the number of observations massed together is so large as to mask small disturbing influences, ON THE PERIODICITY OF THE AURORA BOREALIS. 213 JAKOBSHAVN. e=.78 GOTHAAB. e=1.18 NEWFOUNDLAND. e=1.31 Observed. | Computed. A “a Observed. | Computed. A | x Obseryed. | Computed. A 2 Aa | 14.59 15.92 | — 1.33] 1.7689 | 14.19 14.66|— .47| .2209| 5.96 7.73 | —1.77| 3.1329 12.97 13.18)— .21| .0441] 13.95 14.56]— .61| .8721] 13.25 | 11.18 |-++2.07| 2.2849 SELIG 7.78 | -+-1.41| 1.9881} 11.63 11.42}-+ .21| .0441) 9.27 | 11.47 | —2.20| 4.8400 4 1.90 | — 1.36} 1.8496 4.88 5.87}— .99/ .9801) 10.60 9.27 | + 1.383} 1.7689 0 |— .44\/-+ 44) .1936 0 1.26} —1.26| 1.5876] 7.28 6.81 |-+ .47) .2209 0 |— .16|/-+ .16| .0256 Oj}— .65}+ .65) 4225) 3.31 5.42 | —2.11] 4.4521 O|— .25/-+ .25| .0625 0 |— .12)/+ .12| .0144| 8.60 6.28 | -+ 2.52) 5.5824 0 1.23 | —1.23| 1.5129 1.16 2.95) —1.79| 3.2041] 8.60 9.42 |— .82} 0.6724 9.19 7.62 | +- 1.57 | 2.4649} 12.33 8.23} + 4.10 |16.8100} 10.60 | 11.79 |—1.19} 1.4161 15.14 15.76|— .62| .3844| 10.47 12.93 | —2.46| 6.0516} 12.59 | 10.05 |+- 2.54] 6.4516 18.38 19.56}— .98| .9604) 16.51 14.55} +-1.96| 3.8416) 3.31 5.92 |—2.61]| 6.8121 | 20.00 18.09 | — 1.91)! 3.6481] 14.88 14.33|)+ .55| .3025) 6.62 4.64 |-+ 1.98} 3.9204 100.00 99.99 | {14.9031 | 100.00 99.99 33.8515 | 99.99 | 99.98 39.6247 | QUEBEC. e=1.60 TORONTO. e=.76 NEWBERRY. e=1.10 Observed. | Computed. A » A? Observed. *Computed. A A? Observed. | Computed. A A! 3.55 5.31 |—1.76| 3.0976 5.40 5.92 | — .52| .2704}| 10.55 | 10.02 |+ .53) .2809 14.79 | 11.25 | + 3.54 |12.5316 9.51 7.61 |+-1.90} 3.6100 | 15.61 | 15.44 |-4- .17| .0289 8.28 | 13.12 |— 4.84 |23.4256| 8.74 9.99 | — 1.25] 1.5625| 12.84 | 14.78 |— 1.94] 3.7636 14.20 | 11.88 |-+ 2.382] 5.8824] 11.83 | 10.65 | +118) 1.3924| 13.76 | 10.54 | + 3.22 |10.3684 4.14 6.58 |—2.44| 5.9536| 9.00 9.67 |— .67| .4489 2.75 | 5.38 |— 2.63) 6.9169 5.92 6.00 |— .08| .0064| 6.17 8.07 | —1.90} 3.6100 -92 40 |+ .52| .2704 | 7.69 6.12 |+1.57}| 2.4649} 7.97 6.55 |-+ 1.42) 2.0164 1.38 |—.07 |-+-1.45| 2.1025 | 5.92 7.39 |—1.47) 2.1609 6.43 6.31 | .12] .0144] 5.05 6.81 |—1.76| 3.0976 11.24 | 10.74 |+ .50| .2500|) 848 8.13 |-+ .85] .1225| 14.68 | 14.18 |-+ .50| .2500 12.43 | 10.01 |+ 2.42} 5.8564] 11.05 | 10.21 |+ .84| .7056| 13.76 12.83 |+ .93| .8649 7.69 8.12 |— .43] .1849 8.74 9.74 | —1.00| 1.0000 4.59 5.70 |—1.11| 1.2821 4.14 3.46 |+ .68| .4624 6.68 7.15 |— .47| .2209 4.14 3.97 Sac __-0289 99.99 | 99.98 . |61.7767 | 100.00 | 100.00 14.9740 | 100.03 | 99.98 |29.2051 SALEM. «=1.06 PROVIDENCE. ¢=1.15 CAMBRIDGE. e«=.89 Observed. | Computed. A Ae Observed. | Computed. A ns | Observed. | Computed. A ae 4.54 3.82 |+ .62| .3844) 9.37 7.83 |-+1.54| 2.3716 | 5.10 5.09 |+ .01] .0001 7.07 7.09) |— .52)) 2704 10/63 | 10:86 }— .23] .0529] 8.22 8.80 |— .58| .3364 9.09 9.52 |— .43] .1849| 8.75 9.25 |— .50| .2500| 11.76 | 11.73 |+ .03} .0009 8.59 7.83 |+ .76| .5929| 8.12 8.32 |— .20] .0400} 10.20 9.58 |+ .62| .3844 7.98 7.22 |+ .36| .1296} 11.25 9,48 |-+- 1.82} 3.3124 6.37 5.70 |+ .67| .4489 7.58 9.83 |—2.25| 5.0625] 4.37 7.36 |— 2.99) 8.9401 | 5.10 5.95 |= .8Di) | df 220 15.15 | 11.84 |+ 3.31 |10.9561 | * 6.25 3.52 | + 2.73) 7.4529} 10.34 9.55 |-+ .79| .6241 8.59 | 11.10 |—2.51] 6.3001| 4.87 5.80 |—1.43| 2.0449] 8.50 | 11.45 | —2.95) 8.7025 10.61 | 10.18 |+ .48] .1849) 138.13 | 11.74 |-+ .389| .1521|;13.31 | 10.54 |-+4- 2.77 7.6729 11.10 9.85 |+-1.25| 1.5625) 13.13 | 13.67 |— .54) .2916, 9.21 | 9.11 + .10} .0100 6.06 7.43 | —1.37| 1.8769) 8.75 7.23 |+1.52| 2.3104; 6.80 7.38 |— .58| .3364 4.04 3.81 |-+ .23) .0529) 1.87 3.98 |—2.11| 4.4521] 5.10 5.10 00} .0000 100.00 | 100.02 27.5581 | 99.99 | 99.99 \31.6710 |100.01 | 99.98 19.2391 214 ON THE PERIODICITY OF THE AURORA BOREALIS. WORCESTER. e=1.02 NEW HAVEN. .78 NEW YORK STATE. e=.36 Observed. | Computed. A A? | Observed. | Computed A A? Observed. | Computed. A Ae 8.96 6.65 }+ 2.31} 5.83861) 7.75 7.37 | .388| 1444) 6.31 5.89 | .42| .1764 6.13 8.84 |—2.71| 7.3441] 7.26 7.47 |— .21| .0441| 7.39 7.07 |— 18] .03824 12.74 | 11.89 |--1.35)| 1.8225] 8.86 8.59 | .27) .0729) 9.18 9.62 |— .49| .2401 11.79 | 11.01 |-+ .78| .6084|) 98.24 8.64 |— .40} .1600} 10.95 | 10.01 |+ .94) .8836 4.72 6.63 |— 1.91] 3.6481] 7.63 7.11 |-+ .52| .2704} 7.39 8.12 |— .73| .53829 4.24 3.03 |-+1.21| 1.4641] 5.66 6.36 |— .70| .4900| 6.64 6.64 00} .0000 5.66 5.14 |-+ .52| .2704| 8.86 7.80 |-+1.06| 1.1286) 8.80 8.14 |+ .66} .4356 8.96 | 10.57 |—1.61] 2.5921) 8.11 9.64 |— 1.53} 2.3409] 10.3 11.02 |— .65| .4225 14.15 | 12.90 1.25] 1.5625] 11.93 | 10.02 |+-1.91] 3.6481} 11.70 | 11.61 |+ .09| .0081 10.88 | 10.53 |— .15| .0225| 7.63 9.52 |—1.89| 3.5721) 9.71 9.29 | .42) .1764 7.07 7.28 |— .21| .0441) 10.58 9.10 |-+- 1.48 | 2.1904) 6.22 6.62 ;— .40) .1600 5.19 6.01 | — .82] .6724| 7.50 8.35 |— .85| .7225|) 5.39 5.46 |— .07| .0049 CEES) || sis sis) 25.3873 | 100.01 | 99.97 14.7794 | 100.00 | 99.99 3.0729 ABO. «=.69 SPYDBERG. «=2,31 HAMMERFEST. e=.40 Observed. | Computed. A A? ‘observed. Computed. A A? Observed. | Computed. A Ae 9.68 9.72 |— .04| .0016| 9.88 7.18 | -+-2.70| 7.2900) 20.88 | 21.49 |— .61) .3721 12.76 | 13.63 |— .87| .7569 8.64 | 14.60 | — 5.96 35.5216} 17.58 | 17.20 |+ .38) .1444 14.52 | 13.70 | .82| .6724| 20.99 | 15.70 | + 5.29 |27.9841 8.79 8.44 |-+ .85) .1225 8.94 8.72 |. .22) .0484) 7.41 9.38 | —1.97| 3.8809 0 94 |— .94) .8836 1.32 2.53 |—1.21) 1.4641 2.47 3.07 |— .60| .3600 0 | —.87 |+ .87) .7569 0 | —1.03 1.03} 1.0609 0 |— .88 |+ 88) 1444 0 ol |— .381) .0961 29 00 .29| .0841 | 0 |—1.41 |-+- 1.41} 1.9881 0 12 |— .12| .0144 4.11 5.73 |+—1.62| 2.6244 1.23 5.09 | —1.86| 3.4596 0 01 }/— .01) .0001 14.37 | 12.60 |4-1.77| 3.1829) 12.34 | 12.89 |— .55| .38025 4.40 3.84 | .56) .31386 14.22 | 14.89 |+ .67| .4489) 22.22 | 18.18 |-++ 4.04 |16.3216 9.89 | 10.78 |— .89| .7921 10.85 | 11.44 }— .59| .38481|) 7.41 | 12.57 | —5.16 |26.6256| 17.58 | 16.98 |+ .60| .3600 8.94 8.06 |+ .88| .7744) 7.41 5.12 |-- 2.29} 5.2441} 20.88 | 20.75 |-- .13| .0169 100.00 | 99.99 ik 11.4171 | 190.00 | 100.00 129.1225 | 100.00) 99.99 3.8727 CHRISTIANIA. «=.88 STOCKHOLM. e«=.80 ST. PETERSBURG. e«=.95 Observed. | Computed. A A? Observed. | Computed. A ne Observed. | Computed. A A? 8.61 9.30 |— .69| .4761 7.92 7.15 | .77| .5929 6.54 6.15 |-+ .89) 1521 Al ae 1444) 9.99 | 10.50 |— .51| .2601 9.12 | 11.01 |—1.89} 3.5721 +. .2116| 14.66 | 15.31 |—-+.65| .4225|) 16.76 | 15.36 |+-1.40| 1.9600 +. .7744| 16.42 | 14.45 1.97| 8.8809] 18.81 | 18.22 |-+ .59| .3481 b 5.1529| 3.81 6.13 |— 2.52) 5.3824 8.50 | 5.49 |—1.99) 3.9601 4.4100 0 | —1.36 1.36) 1.8496 1.20 |— .61 |+ 1.51) 2.2801 1849 0 |— .20 20) .0400 1.58 1.16 -22| 0484 1.7161 5.57 6.80 | — 1.23) 1.5129 5.89 | 7.46 |—1.57)| 2.4649 3.1684| 12.90 | 11.71 |--1.19| 1.4161] 18.81 | 12.47 |-+ 1.34) 1.7956 .7744| 11.44 | 11.92 |— .48| .2304| 13.08 | 12.80 |-- .28) .0784 29116 9:99 9.90 |} .09|) .0081 7.64 | 9.87 |—1.73}| 2.9929 1.6129} 7.33 7.68 |— .85] .1225 7.27 | 5.81 |-+-1.46] 2.1316 18.9177 | 100.03 | 99.99 15.7184 | 100.00 21.7843 ON THE PERIODICITY OF THE AURORA BOREALIS. 215 = UPSAL. e=.72 DUNSE. «=1.11 MAKERSTOUN. e=.738 Observed. | Computed. ie A? Observed. | Computed. A A? Observed. | Computed. A Aa 8.35 9.47 | —1.12| 1.2544] 13.87 | 11.85 + 2.02 4.0804} 11.96 9.96 | + 2.00| 4.0000 12.87 | 138.20 |— .43] .1849 8.40 | 10.10 | 4.70] 2.8900] 14.13 | 14.96 | —1.26] 1.5876 14.93 | 13.71 |-+ 1.22} 1.4884 7.56 7.37 + 19] .03861} 15.22 14.96 |+ .26| .0676 7.37 8.14 ]— .77| .5929 7.56 6.02 + 1.54 2.38716] (8.70 8.62 08} .0064 .69 1.21 }— .52| .2704 1.26 3.34 | 2.08 | 4.3264 3.26 3.01 25) .0625 20 |— 1.22 1.44) 2.0736 0 |— .92 + .92 0.8464 0 52 |}— .62| .2704 39 1.56 | —1.17| 1.3689 84 |\— .18 + 1.02 1.0404 0 |— .09 |+ .09| .0081 7.07 | 6.89 |-+ .18| 0.0324] 5.88] 818 |930| 5.2900] 380] 2.95 |+ .85| .7225 12.388 | 12.00 |— .88| .1444] 18.07 | 15.87 + 2.20 4,8400 8.70 | 10.138 |—1.48 |} 2.0449 14.34 | 14.16 |-+ .18} .0324/ 14.29 | 15.62 |_-1.33] 1.7689] 15.76 | 14.84 |+ .92] 0.8464 10.71 | 12.03 | —1.32] 1.7424] 12.60 | 11.71 + .89 -7921| 12.50 | 12.02 |-+ .48| .2304 10.71 8.84 |-+ 1.87 | 3.4969 9.66 | 11.01 | — 1.35 | 1.8225 5.98 7.72 | —1.74]| 3.0276 100.01 | 99.99 12.6820} 100.00 | 99.97 | 30,1048 | 101.01 | 100.12 12.8744 G. BRITAIN. c=.61 BERLIN. e=1.04 UTRECHT, &. e«=.84 Observed. | Computed. A A? Observed. | Computed. A A? Observed. | Computed. A A2 8.96 | » 7.80 |-+ 1.16} 1.3456 7.04 5.61 |-+ 1.43] 2.0449 6.53 5.45 |+1.08] 1.1664 8.51 9.07 |— .56} .381386) 10.85 | 11.43 |— .58| 3364 6.27 7.08 |} — .81] .6561 11.26 | 10.65 |-++ .61) .3721] 16.42 | 16.61 |— .19| .0361) 12.27] 11.48 |+ .79] .6241 10.11 | 10.01 }+ .10} .0100; 15.54 | 15.75 |— .21| 0441} 138.73 | 15.07 | —1.84] 1.7956 5.52 6.14 |— .62|) .3844| 11.44 9.72 |+1.72| 2.9584) 14.67 | 12.68 |+-1.99| 3.9601 1.61 1.50 }-+ .11] .0121 09 3.37 | — 2.78 | 7.7284 4.53 6.46 | — 1.93] 3.7249 69 75 |— .06| .0056 2.93 0.74 | +-2.19 | 4.7961 4,93 4.08 | .85) .7225 5.52 5.68 |— .16] .0256 2.98 3.08 |— .15| .0225 7.87 7.25 |+- .62| .3844 13.33 | 12.21 |-++1.12]| 1.2544 6.45 8.22 |—1.77] 3.1329 8.53 9.99 |— 1.46) 2.13816 13.56 | 14.77 |— 1.21) 1.4641} 18.20 | 11.23 |+- 1.97] 3.8809 9.87 8.73 |+1.14| 1.2996 13.56 | 12.43 |+-1.13) 1.2769 8.50 9.09 | — .59| .3481 6.27 6.32 |— .05| .0025 7.35 8.97 | — 1.62] 2.6244 4,11 5.13 | —1.02} 1.0404 4.53 5.40 |— .87| .7569 S)Sishsr |] ESVGKs) | 9.0868 | 100.00 | 99.98 26.3692 | 100.00 | 99.99 17.2247 FRANEKER. ¢«=1.50 JENA. ¢=1.91 MANNHEIM. e=1.23 Observed. | Computed. A A? Observed. | Computed. A A? Observed. | Computed. A A? 8.65 6.66 | +1.99 | 3.9601 2.38 5.12 | — 2.74) 7.5076 8.33 5.57 | + 2.76 | 7.6176 6.49 | 10.74 | — 4.25 |18.0625| 10.71 7.90 |-+ 2.81 | 7.8961 5.55 8.64 |— 3.09 | 9.5481 17.75 | 13.56 | + 4.19 |17.5561 4.76 | 10.73 |—5.97 |35.6409 | 15.28 | 13.71 | 41.57) 2.4649 9.96 | 12.10 | —2.14]| 4.5796] 11.91 9.94 1.97 | 3.8809] 14.81 | 14.10 |+ .71] .5041 6.93 6.86 |-+ .07| .0049 4.76 7.41 | — 2.65} 7.0225 6.02 7.90 |—1.88} 3.5344 2.60 2.26 |)-+ .84)] .1156 2.38 3.42 | —1.04| 1.0816 3.70 2.68 |-+ 1.02) 1.0404 3.46 2.78 68] .4624 4.76 3.40 | + 1.36] 1.8496 5.55 4.62 |+ .93} .8649 6.49 7.94 |—1.45] 2.1025 9.52 9.75 |}— 23] .0529 7AL 9.64 | — 2.23 | 4.9729 12.99 | 12.33 |-+ .66) .4856} 16.67 | 15.07 | +-1.60| 2.5600} 12.96 | 11.05 |+-1.91| 3.6481 12.99 | 11.79 |-+- 1.20) 1.4400] 17.86 | 14.07 | 4-38.79 \14.3641 8.33 9.05 |— .72} .5184 5.63 7.79 | —2.16| 4.6656} 7.14 8.27 |—1.138) 1.2769 7.Al 7.15 26) .0676 6.06 5.17 |-+ .89| .7921 7.14 4.91 |-+ 2.23) 4.9729 4.63 5.89 | —1.26] 1.5876 100.00 | 99.98 SATO) |) SSIS) | SEEKS) 88.1060} 99.98 | 100.00 36.3700 216 ON THE PERIODICITY OF THE AURORA BOREALIS. SAGAN. e=1.69 BRUSSELS. e=.69 PLYMOUTH. e«=1.36 Observed. | Computed. A A? Observed. | Computed. A A2 Observed. | Computed. A Az 10.42 5.73 | + 4.69 21.9961 5.19 5.34 |— .15] .0225 6.67 4.22 | + 2.45] 6.0025 5.83 9.20 | — 3.37 |11.3569 5.63 5.66 | — .03| .0009 5.83 9.41 | — 3.58 |12.8164 14.17 | 14.41 |— .24] .0576 7.79 7.30. 49} .2401 | 19.17 | £15.55 | + 3.62 |13.1044 16.67 | 13.54 | +-3.13 | 9.7969 9.52 | 10.94 |— 1.42} 2.0164] 10.00 | 12.26 |— 2.26] 5.1076 3.93 6.389 |—3.06| 9.3636) 16.45 | 14.05 |+ 2.40} 5.7600 5.00 3.98 |-+- 1.02] 1.0404 83 17 |+ .66| .4356 9.56 | 12.66 | —3.10| 9.6100 83 1.87 | —1.04} 1.0816 1.25 |— .11 |-+-1.36} 1.8496 9.56 7.93 |-+ 1.63) 2.6569 6.67 5.64. 1.03 | 1.0609 3.33 4.34 |—1.01} 1.0201 4.76 5.52 |— .76| .5776 6.67 7.82 | —1.15]| 1.8225 9.17 | 10.17 | —1.00); 1.0000 6.93 7.28 | — .85]| .1225 8.33 8.47 |} — .14] .0196 16.25 | 14.17 |+ 2.08| 4.5264 9.96 9.12 |+ .84| .7056] 12.50 | 11.21 1.29 | 1.6641 12.92 | 13.41 |— .49| .2401 7.36 8.10 |— .74| .5476] 10.83 | 12.13 |—1.380| 1.6900 5.83 8.59 | — 2.76 | 7.6176 6.49 6.10 | .89| .1521 7.50 7.43 |+ .07) .0049 100.00 | 100.01 69.0605 | 100.00 | 100.00 22.4122 100.00 99.99 44.9149 CARLSRUHE. «=1.02 PARIS. e=2.42 MONTMORENCI. ¢«=1.02 Observed. | Computed. A A2 Observed. | Computed. A ae Observed. | Computed. | A | A? 2.30 2.89 |—- .59] .3481 3.70 4.29 |— .59| .3481 4.76 4.21 00} 020 10.34 8.61 |-+ 1.73 | 2.9929 4.63 5.12 |— .49| .2401 7.74 9.65 |— 1.91} 3.6481 14.94 | 16.73 | —1.79| 3.2041] 11.11 7.19 3.92 |15.3664| 15.48 | 13.19 |+ 2.29) 5.2441 17.24 | 16.69 |+ .55} .8025 3.70 | 10.61 |— 6.91 |47.7481| 10.71 | 12.17 |—1.46} 2.13816 9.20 8.87 | .83|] .6889] 18.52 | 11.69 |+ 6.83 |46.6489 8.33 7.89 | .44| .1936 2.30 3.19 |— .89} .7921 4.63 8.28 | — 3.65 |13.3225 3.97 3.91 |— .84) .1156 5.75 6.29 | — .54| .2916 5.56 5.45 |+ 11 -0121 5.36 4.03 |-+- 1.33 | 1.7689 12.64 | 10.385 | 2.29} 5.2441 9.26 8.31 |+ .95 9025 6.55 8.90 | — 2.35 | 5.5225 6.90 9.71 | —2.81| 7.8961 | £13.89 | 13.17 |+ .72 5184} 16.07 | 13.78 |-+ 2.29 | 5.2441 . 9.20 7.45 |-+-1.75| 3.0625) 10.19 | 12.98 | —92.79 | 7.7841] 11.90 | 12.92 | —1.01/ 1.0201 5.78 6.00 | — .25} .0625) 11.11 8.22 | + 2.89 | 8.3521 6.55 6.88 |— .383} .1089 3.45 3.70 | — .25| .0625 3.70 4.68 |— .98]| .9604 2.98 2.44 |-+ .54| .2916 100.01 | 99.98 24.9479 | 100.00 | 100.00 142.2037 | 100.00 | 99.97 25.5916 WITTEMBERG. ¢«=1.64 PTATLY. e—2'34 MEAN CURVE. e=.30 Observed. | Computed. A | A: Observed. | Computed. A Ag Observed. | Computed. A A? 8.79 8.61 }+ .18] .0324 4.54 5.08 | — .54 .2916 9.54 9.13 |-+ .41 1681 13.19 | 18.65 |— .46|) .2116| 10.23 | 14.27 | — 4.04 / 16.3216 9.73 | 10.55 |— .82 6724 14.29 | 13.84 }-+ .45| .2025| 23.86 | 17.83 |+ 6.03 | 36.3609] 11.96 |. 11.32 + .64| .4096 7.69 8.35 |— .66| .4356 5.68 | 10.06 | — 4.38 | 19.1844 9.37 9.40 | — .03 0009 3.30 2.38 |-+ .92| .8464 3.41 2.34 |+1.07} 1.1449 5.09 5.53 | — .44 1936 0 | 48 |— .48| .2304 4.54 3.56 |+ .98 -9604 3.22 2.86 |+ .36 1296 220°} 93.29) | == 1.09; 1.1881 6.82 7.61 |— .79 .6241 3.72 3.61 |-+ 11 0121 12.09 8.87 | -+ 3.22 10.3684 7.95 8.06 |— .11 -0121 6.45 6.91 |— .46| .2116 8.79 | 15.44 | — 4.65 |21.6225 7.95 8.48 |— .53| ~ 2809} 10.39 | 10.08 |+ .31 0961 17.59 | 13.08 4.51 |20.3401 | 13.64 | 10.58 |+ 3.06| 9.8636] 11.87 | 11.20 |+ .17| .0289 5.50 8.42 |— 2.92] 8.5264 3.41 8.65 | — 5.24 | 27.4576 9.87 | 10.84 |— .47 2209 6.59 5.56 | + 1.03} 1.0609 7.95 3.46 | + 4.49 | 20.1601 9.29 9.08 |-+ .21) .0441 100.02 | 99.97 65.0653 | 99.98 | 99.98 132.1622} 100.00 | 100.01 2.1879 S ON THE PERIODICITY OF THE AURORA BOREALIS. PALL In 1843 Ekléf? published at Helsingfors, Russia, a mathematical discussion of the an- nual changes of the auroral phenomena, making use of the same periodic function as I have adopted. ? P,, = 8.33 + uv’ sin. (m30°-+ U') +-w" sin. (m 60° + VU”) 4- wv” sin. (m 90° +- 0”). He also has reduced all the observations to the uniform standard of one hundred for the twelve months of the year. As in his formula (m) is equal to zero for January 1, the time counts from January 1, whereas I take January 15 as the initial day of the year. Accordingly my values of ¢c, exceed by 15° and multiples of 15° the values of U* com- puted by Ekléf. This should be remembered in comparing his formulas with those which I have computed for the same places. There is an advantage in this comparison, inas- much as the observations which he used generally refer to a different period of years from that which I included in my calculations. For this purpose I append his conclusions. Berlin, -P,=8.33-3.46 sin. (m30°+-110° 22’)-1-6.97 sin. (m 60°-+265° 97’)-13.37 sin. (m 90°+-277° 35’). London, P,,=8.33-15.66 sin. (m30°+121° 32’) +5.33 sin. (m 60°-+-257° 55’)-1.57 sin. (m90°-++-248° 26/). Upsal, P,,=8.33-15.42 sin. (m30°+-101° 48’) 13.94 sin. (m 60°+283° 24’) 10.94 sin. (m 90°+281° 22’). St-Petersh’g, P,—=8.33-13.99 sin. (m30°-+129° 41’) 17.77 sin. (m 60°-+-278° 28’) 11.17 sin. (m90°-+272¢ 30’). Italy, P,,=8.33-++1.97 sin. (m 30°-L 48° 38')+-4.85 sin. (m 60°+305° 49’) 13.24 sin. (m 90°-+-245° 37’). Utrecht, P,=8.33-+2.29 sin. (m 30°-1336° 8’)-13.64 sin. (mm 60°-+251° 16’)-11.40 sin. (m90°+ 86°34’). Carlsruhe, P,—=8.33-+-2.73 sin. (m 30°+337° 28’)+5.11 sin. (m 60°-+282°59’)1-2.34 sin. (m 90°+170° 0’). Mtmorenci, P,,=8.33-+1.21 sin. (m 30° 71° 44’)+-4.07 sin. (m 60°+-279° 46’)-+0.71 sin. (m 90°4-14° 4’). Wittemberg, P,,—=8.33-+-3.29 sin. (m 30°+104° 46’)1-5.33 sin. (m 60°-+303° 25’)-+0.76 sin. (m 90°-+-300° 58’). Place. Years. Authority. | Min. |Value.| Max. |Value.| | Min. | Value. | Max. | Value.| Pin. Berlin, 1707-85 |Kirch, Jan. 1) 1.28 March 10/15.94 July 16) 1.26/Oct. 19)19.39) 1.51 London, 1716-50 |Eklof, Jan. 14, 5.65|/March 16 Ge 17) 0.58/Oct. 25/18.43) 2.20 Upsal, 1716-33 /Celsius, |Dec. 27) 8.85 March 1 WP ee 19} 0.11/Oct. 1814.45 0.65 St. Petersburg, [1726-36 |Delisle, Jan. 0, 2.55)/March eee une 19) 1.72)Oct. 7)18.87) 1.03 Italy, 1727-51 |Beccari, |Dec. 27) 2.81/March 918.14 May 26) 1.79\Oct. 21/10.70) 2.34 Aug. 27) 7.92} Aug. 2) 8.24 Utrecht, &e., 1716-44 |Musschen-|Jan. 0) 5.35 April 2015.16 July 11) 4.00/Sept. 19/10.04) 0.91 Carlsruhe, 1779-1831 are Jan. 6 2.59 March 018.13 June 17) 3.18 Aug. 2610.63) 1.01 | Montmorenci, &e.,.1771-80 |Cotte,? |Dec.16 5.15|March 19/12.23 July 3) 2.96)/Sept. 2812.67) 0.64 | Wittemburg, 1731-50 |Weidler, |Dec. 15 5.57)March 114.61 June 11) 0.42|Sept. 28.14.07) 1.64 | 1 Acta Soc. Sci. Fennice, IT. 302. 2 This is the same as I employed in 1845, in discussing the daily changes of temperature and magnetic declination. — Memoirs of the American Academy, IT. 44. Moigno, Lecons de Calculus, I. 527. Liouville, Journ. de Math., I, 193. 8 As giyen by Bertholon, Kimtz, and Gehler. Cotte’s Memoirs, &c., I. 366. VOESEX: 28 218 ON THE PERIODICITY OF THE AURORA BOREALIS. Quetelet! has given careful attention to the inquiry, whether any relation exists be- tween the periodicity of the aurora and of shooting stars. He draws attention to the fact that while Mairan rejected the idea of any relationship between the two classes of phenomena, because he supposed auroras to be cosmical and shooting stars terrestrial in their origin, at the present day the shooting stars are believed to be of a planetary character and the aurora to be comparatively near to the earth’s surface. Quetelet ad- mits that the periodicity of auroras conforms to the recurrence of the seasons, and exhibits nearly the same periods of maxima and minima now as formerly, whereas the periodicity of the shooting stars stands in a less definite relation to the seasons, and the November period of maxima appears to have come in ancient times as early as the last days of October, and the August period between July 25 and 30. He rests his argument in favor of some affiliation between phenomena apparently disconnected on the fact that, out of twenty-eight unusual exhibitions of shooting stars since 1830, fifteen have been accompanied or preceded by auroras; viz, December 7 and 12, 1830; August 10 1831; November 13 1832; December 12, 1833; August 12, 1834; August 10 and November 15, 1836; November 15, 1837; October 18, November 15, and December 7, 1838; January 2,1839; January 2, 1840; and August 11, 1841. Moreover, on August 15, 1830, and on November 12 and 14, 1839, when the expected display of shooting stars nearly failed, its place seemed to have been taken by an exhibition of aurora. Quetelet arrives at the following judicious conclusion : — “ Ces rapprochements ne prouvent sans doute pas que les ¢toiles filantés et les aurores boréales doivent étre rangeés dans une méme classe et ont une méme origine: mais on peut raissonablement supposer que les causes qui aménent les unes peuvent favoriser la naissance des autres.” Wartmann? has also argued in favor of the common origin of shooting stars and the aurora, resting his proof on a few coincidences, such as those which happened on Decem- ber 16, 1830; October 18, 1836, July 28, 1837; May 7, September 2, and October 22, 1839; July 5 and September 21, 1840. Facts such as the following have been quoted by others as indicating a relationship between the shooting stars and the aurora. Von Wrangel® observed, while in Siberia, that when shooting stars crossed the path of the aurora fiery beams started up in the space traversed. Airy* saw a single star shoot from the auroral beams of March 13, 1833. Bravais, while in Scandinavia, recorded one example of stars shooting from the region of the aurora. 1Nouy. Mém. de l’Acad. Royale de Bruxelles. XV. 14. 2 Bibliotheque Universelle, XXX. 206 ; and Quetelet’s Correspond. Math. et Phys. XI. 182, 3 Edinburgh New Phil. Journal, 1827, III. 381. * London Philosophical Magazine, 3d Series, I. 316. 5 See also on the same subject Wochenschrift fiir Astronomie, &c., II. 287. ON THE PERIODICITY OF THE AURORA BOREALIS. 219 Boué’ has labored assiduously to establish a connection, such as is implied in a com- mon origin, between different portions of the Physics of the Globe, and, possibly besides, between shooting stars and the zodiacal light. He questions the periodicity of the latter, and claims no correspondence in the periods of shooting stars and the aurora. But he argues earnestly, though in my opinion not very conclusively, in favor of some affiliation between auroras and earthquakes. He quotes largely from the voluminous catalogues of earthquakes published by Perrey in the Mémoires de L’Academie Impériale de Dijon and elsewhere. Perrey has arranged his data by months, years, and centuries, and finds some evidence of a secular period as well as of a yearly one. He also points out a coincidence between the periodicity of earthquakes and the monthly tides, the maximum appearing at syzygies and the minimum at quadratures. They are also more frequent when the moon is near the meridian than they are when the moon is 90° from the meridian. The monthly change he has developed by a periodical function similar to that which I have employed upon the aurora. Of the earthquakes which oc- curred in France, Belgium, and Holland, Perrey has made the following distribution among the months.” The second line of the table refers to earthquakes observed in the Antilles;* the third line to those observed in the Isle of Zante;* the fourth to those observed in Europe and the adjacent parts of Asia and Africa; the fifth to those observed in the whole of the Northern Hemisphere, as compiled by Mallet.’ Place. Jan. Feb. March. | April. May. June. July. Aug. Sept Oct. Noy. Dec. | Total. France, &c., 85 64 53 5d 42 36 47 40 50 48 60 78 | 606 Antilles, 15 16 23 17 16 16 20 25 22 20 18 15 | 221 Zante, 80 | 107 | 105 89 | 18] | 176 | 141 | 131 91 |.165 | 279 | 168 |1663 Europe, &e., 228 | 189 | 172 | 147 | 126 | 181 | 148 | 147 | 147 | 176 | 148 | 202 |1961 N. Hemisphere, 627 | 539 | 503 | 489 | 488 | 428 | 415 | 488 | 463 | 516 | 473 | 500 |5879 The frequency of earthquakes varies from month to month, but there is no resem- blance between the law which governs this change and the yearly course of the aurora, or between the two sets of maxima and minima. The nearest approach to such an agreement is in the summer minimum. Boué attaches value to the fact that out of three hundred and fifty-one auroras observed by Hansteen and Herrick between 1837 and 1847, and four hundred and fifty-seven earthquakes compiled by Perrey, forty-seven cor- respond in the day and five in the hour of the occurrence, and fifty more coincide in time within one or two days. When Boué compared the same earthquakes with his own cata- logue of eight hundred and eighty-three auroras, he found half of them to correspond within a day or two to some aurora, and from eight to ten within a single hour. 1 Sitzungsberichte der Kaiserl. Akad. der Wissensch. XII. 459, 60. 2Mém. Couronn. et des Savans Etrang de l’Acad. Brux. XVIII. 97. 8Mém. de l’Acad. Impér. de Dijon, for 1845,6, p. 385. 4 Mém. de l’Acad. Impér. de Dijon. Deuxieme Serie, XI. 103. © Report of the British Assoc., XXVIII. Meeting, pp. 28 and 57. 220 ON THE PERIODICITY OF THE AURORA BOREALIS. I translate the following passage from Boué : — “Tf the monthly frequency of northern lights and earthquakes is compared for a series of years, a decided and gen- eral correspondence is discovered between the tables of northern lights given by Mairan, Bertholon, and Muncke, and those which Perrey has made of earthquakes since the fourth century in northerly Europe and Asia, in western Europe, as well as in eight different basins and in south-eastern Europe. I do not mean a relative coincidence of numbers, but a somewhat similar mutual proportion of numbers for both classes of phenomena in each month of this series of years. If the tables of Perrey are compared with Hansteen’s registers of the northern lights, the greatest disagreement falls upon the months of February and March as well as September and October. But May, June, July, and even August retain the same character for both classes of phenomena, as the months of minimum frequency. Decidedly in July and pre- eminently in June both are of great rarity.” + Baumhauer? has classified the recurrences of meteoric stones and fire-balls as follows: Days. Jan. Feb. March April | May | June July Aug. Sept. Oct. Noy Dec. | Total. 1 4 2 5 Ds 1 4 : 4 6 1 3 28 2 6 : 3 1 2 2 : - : 2 1 aa 21 3 1 4 2 1 - 3 1 6 1 3 iL 1 24 4 2 2 1 3 1 2 Dio il* OL 4 i 3 2 24 5 1 5 5 3 1 1 é 4 2 1 2 3 18 6 2 7 2 2 : 1 1 5 1 3 4 1 29 7 2 3 1 - 2 2 1 5 “ 1 2 5 19 8 3 t 5 2 2 S 1 4 4 4 i 4 34 ving 3 2 2 5 1 4 . 2 2 : 4 2 27 10 3 2 2 4 3 2 7 ff 2 2 2 34 11 1 2 1 3 1 : 1 3 1 4 2 4 23 12 3 1 4 1 2 3 1 5 : 3 8 2 33 13 6 1 3 3 1 3 4 3 6 3 9 6 48 14 1 1 2 1 1 1 1 2 3 1 3 2 19 15 3 2 3 1 1 1 : 4 - : 2 2 19 M < 1 1 zs - . 2 1 1 : < = 6 16 2 : at 5 2 1 3 1 3 1 2 2 18 17 1 1 5 4 5 2 10° J 3 4 2 32 18 2 6 2 2 1 = 2 2 1 2 2 3 25 19 : 3 1 4 4 4 1 2 1 1 5 2 28 20 2 1 : 2 : 3 4 2 5 4 1 24 21 1 1 2 : 2 5 2 3 2 2 1 3 14 22 : il: 4 5 6 1 1 4 3 3 1 3 27 23 1 2 1 5 1 = 1 4 2 5 1 - 18 24 3 5 2 : . 3 Fi 2 2 1 2 15 25 3 1 1 : * 5 . 1 1 3 3 13 26 aa 3 = 3 2 2 2 1 af 2 1 21 27 2 4 E 2 2 1 5 ci 3 4 1 19 28 3 1 1 3 1 1 4 3 2 al 2 1 23 29 5 2 2 1 2 6 : 2 1 i) 3 24 30 2 4 2 1 1 2 - 1 1 2 2 18 31 1 2 c 2 P 2 - d 2 : 1 10 F 1 > 4 : 3 c 5 4 () 0 1 1 3 1 4 6 4 1 3 4 28 Total. 69 58 62 | 54 53 37 62 83 61 69 87 72 767 1 Sitzungsberichte der Kaiserl. Akad. der Wissensch. Wien. XXII. p. 434. 2 Pogg. Annalen der Physik und Chemie, LX VI. 477. ON THE PERIODICITY OF THE AURORA BOREALIS. 22% The days signalized by the frequency of these phenomena are November 12 and 13, August 10, April 9 and 10, December 13, November 27, 28, and 29, January 1 and 2 (all of which days according to Quetelet are distinguished by extraordinary numbers of shooting stars), and especially July 17. Baumhauer takes advantage of the fact that fire-balls, &c. are often surrounded, when they first appear, with a cloudy envelope. As nickel and magnetic iron enter largely into the composition of meteoric stones, he concludes that these substances are also one principal ingredient in the lighter matter which remains suspended in the air without falling to the earth. Hence he conjectures that this floating matter will be magnetized by the earth, arrange itself everywhere parallel to the resultant of the terrestrial magnetic forces at each place, and manifest itself, when from any cause rendered luminous, as the Aurora Borealis or Australis. Baumhauer thinks it desirable that the ground in high latitudes should be searched for nickel, since it is distributed so sparingly over the earth’s surface that its presence at any place might be taken as a safe indication of meteoric materials.. He adds that this hypothesis as to the origin of northern lights is sustained by the observations of Colla, Wartmann and Quetelet, who have pointed out the fact (?) that the times when the northern lights are most abundant coincide with the periods of greatest meteoric dis plays. Baumhauer modestly allows that his speculation in regard to the mutual dependence of various classes of phenomena in the Sun’s system, viz., shooting stars, the fall of meteoric stones, and the northern lights, is only an attempt to introduce some order into what has been hitherto an immense chaos of facts. Wolf has supplemented from his own learning the catalogue of meteorites and fire balls, made by Kiimtz and Biot.’ He assigns to each day its proper number and pub- lishes the following monthly means: May. | June.}| July. | Aug. | Sept. | Oct. | Noy. | Dec. | Total. Kimitz — Wolf, _ i 82 59 71 65 59 | 48 60 85 74 | 79 | 101 92 | 875 Biot, c j b4 |] 54 68 61 89 | 75 | 151 | 181 | 116 } 183 | 144 90 | 1216 Coulvier—Gravier, 4 6 4 3 5 i 15 | 40 13 11 16 UI | 185 Wolf selects the following days as conspicuously marked by the frequency of these occurrences : January 2 and 10; February 4, 6, and 18; March 1 and 31; April 9, 10, and 19; June 7; July 17 and 29; August 3, 5, 7, 8, 10 and 1; September 1 and 13; October 1 and 3; November 9, IJ, 12, 13, 16,19 and 29; December 2, 8, 11, 13, and 30; “also namentlich auch die Tage, welche sich constant oder wenigstens in einer gris- 1 Vierteljahrsschrift der Naturforsch. Gesellschaft in Ziirich. Jahrgang I. 322-32, 222, ON THE PERIODICITY OF THE AURORA BOREALIS. sern Anzahl von Jahren besonders reich an Sternschnuppen zeigten.” Neither the : days nor the months which are stamped with a deficiency or a superabundance of auroras reappear in these new phenomena as equally memorable. Wolf? has arranged a collection of 5764 auroras, according to the days and months of the year. He has then constructed three curves: 1, the first according to the twelve monthly means; 2, the second according to the daily numbers; 3, the third according to means of each five successive days, giving six ordinates for every month. His max- ima derived from the latter curve are near March 20 and October 15, and the minima near June 22 and December 25. The jaggedness of the second curve he attributes mainly to accidents of observation, remarking, however, that January 3 and 6, February 11 and 22, March 26 and 29, May 1, September 24, November 2, and December 20, are rich compared with the curve of monthly means; while February 14 and 21, March 31, October 28, and November 5 and 28 are comparatively lean. Moreover the third curve mounts unusually high during the first week of January and of July, that is, shortly after the periods of minima, and exhibits unusual depressions near the end of April and November. But these subordinate waves, which ride the back of the great yearly swell as a deferent, do not seem to me to point with any certain aim to the times for shoot- ing stars and, through them, to the ring of meteors and the zodiacal lights. Wolf compares his Northern Light curve with the yearly changes of Magnetic Inclination as found by Hansteen, of magnetic storms as studied by Sabine, and of Solar Spot fre- quency? and Magnetic Declination as developed by his own researches, and he declares in favor of a prevailing agreement between them as exact as can be expected from the nature of the observations. “ Diese Vergleichung zeigt, dass im Allgemeinen wirklich eine so grosse Uebereinstimmung zwischen den verschie- denen Curven herrscht, als nur immer bei der Natur der zu Grunde gelegten Beobachtungsreihen erwartet werden kann, und wenn das erste Maximum der Nordlichtcurve vergleichungsweise etwas friihe, das zweite etwas spit einzu- treten scheint, so ergibt sich hiefiir eine einfache Erklariing aus dem Zunehmen der Tageslinge im Friihjahr und dem Abnehmen der Tagesliinge im Herbst, — ebenso fur das relative Verfriihen der beiden Minima’s aus der durchschnitt- lich ungiinstigeren Witterung um die Zeit der Solstitien. Auch die grosse Differenz zwischen den beiden Minima’s der Nordlichtcurve wird offenbar durch die Verhiiltnisse der Tagesliinge ungemein begiinstigt.” A. de la Rive argues in favor of some association between appearances of the aurora and lunar halos, rain, snow, ec. “ Revenant & la coexistence des particules glacées dans l’air avec les aurores, nous en trouvons une preuve frappante dans les observations faites au Canada et aux Etats-Unis. Des registres d’observations météorologiques, tenus avec beau- 1 Vierteljahrsschrift der Naturforsch. Gesellschaft in Ziirich. Jahrgang II. 372, 3. 2 Vierteljahrsschrift der Naturforsch. Gesellschaft in Ziirich. Jabrgang I. 161, 263, and 269. ON THE PERIODICITY OF THE AURORA BOREALIS. 223 coup de soin, indiquent l'état de l’atmosphére les jours qui précédent et qui suivent l’apparition d’aurores boréales. Or, presque toujours, l’aurore est précédée de la chute de la pluie et surtout de la neige; il arrive aussi trés-souvent, mais non tonjours, que cette chute a lieu aprés ’aurore. Enfin, l’apparition des halos luminares, qui précéde le plus souvent celle des aurores boréales, est une preuve de la présence dans l’atmosphére de ces particules glacées qui forment le réseau illuminé par la transmission de I’électricité.”* Wartmann has considered the question, whether there is a special period of auroral display in October2 The influence of trade-winds and of a low barometer upon the aurora has also been discussed.? Broun has examined the recurrence of auroral dis- plays in connection not only with the seasons, but also with the moon’s age and mag- netic disturbances. From his own short series of observations he has concluded that these disturbances, whatever and whenever they may be, which result in the develop- ment of the auroral light, agree with the magnetic disturbances of the earth in having a maximum at the opposition of the moon, and a minimum at the conjunction. These magnetic disturbances also conform to another law of the aurora; viz., they have max- ima at the equinoxes and minima at the solstices, particularly at the summer solstice.* Hansteen’ has pointed out a yearly period in the changes of the magnetic inclina- tion at Christiania; the two maxima occurring on April 1 and September 30, and the two minima on July 1 and December 31. If the solar spots can be linked with the -earth’s magnetism, and if the earth’s magnetism can be associated with the aurora, may not the aurora and the sun’s spots possess some bond of affinity? The solar spots have been tabulated by Wolf, month by month. The yearly curve resembles the variation in the star 6 Lyre as found by Argelander. The principal minimum is in July, and a secondary one in November: the principal maximum is in October, and a secondary one in December. This yearly curve corresponds to that which expresses the mag- netic changes as far as the principal maximum and minimum are concerned. But the magnetic curve has a secondary maximum in April and a minimum in January. Both phenomena exhibit clearly an annual periodicity; there are more solar spots from October to March inclusive than from April to September inclusive. Wolf’ expresses the monthly frequency of the solar spots between the years 1833 and 1858 inclusive, by these relative numbers. 1 Traité de l’Electricité, ITI. 295. 2 Bibliotheque Universelle, XXX. 206, 8 Bibliotheque Uniyerselle, XLV. 89, and LXXXIII. See also the calculations of Fritz. Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich. IX. 124-8. 4Edinb. Phil. Trans. XIX. Pt. 2, p. Ixxxi. 5 Bulletin de Acad. Royale de Brux. XXI. 299. Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich. Jahrgang, II. 123, and 353; V. 36; VI. 179. © Biblioth. Univ. Archiv. de Nat. et Phys. Sci. VIII. 41. 7 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich. Jahrgang, I. 264; II. 120; V. 29 and 240. 224 ON THE PERIODICITY OF THE AURORA BOREALIS. Jan. Feb March. April. | May. June.| July. Aug. Sept Oct. Noy. Dec. | | 48.6| 47.7| 45.3| 44.2| 44.0] 48.4| 42.3] 46.0| 50.4| 52.6| 46.2 50.7 || Wolf made an elaborate comparison, month by month and year by year, for the whole period between the years 1826 and 1848 inclusive, of the number of solar spots seen on days when the aurora was observed as compared with the general average. If the evidence was not decisive, it at any rate leaned to the opinion of Mairan that the aurora was concomitant with the development of solar spots more frequently than oth- erwise. He alludes emphatically to the spots and the aurora of the last of August and the first of September, 1859. Ill. Pliny, after describing appearances in the heavens which evidently refer to the aurora borealis, adds these words: “Atque hee ego statis temporibus nature, ut cetera arbitror existere.” Ideler’ quotes this passage with the following comment; “Novitne Plinius statis periodis auroram borealem apparere?” I have stated in an earlier me- moir” the general argument for a secular periodicity in the recurrences of the aurora borealis. An appearance which is now so familiar was so strange in 1719 that the aurora of that year caused such terror throughout New England as to suspend “all amusements, all business, and even sleep, there being a general expectation of the ap-. proach of the final judgment.”* In the early part of the present century the inhabi- tants of the Shetland Islands complained of the loss of this useful light which was so common in the last quarter of the preceding century; and the necessity of substituting artificial iJumination for ordinary farming purposes. The experiences and traditions of the Icelanders are of the same kind. Henderson® said in 1815: “I had an opportu- nity of contemplating them (auroras) almost every clear night during the whole win- ter.” Compare this with the accounts of Anderson for the period between 1730 and 1747, and of Horrebows in 1749 and 1750. Although there can be no doubt in regard to the fact of the secular periodicity of the Aurora Borealis, there may be great difficulty in ascertaining, with even an approxima- tion to certainty, the period of this secular change: partly, because the period is long, and demands centuries of careful observations before it can be unmasked; partly, because the secular change is evidently entangled with other changes of smaller periods which there may be no means of eliminating. I have drawn the secular curve 1 Meteorologia Veterum Grecorum et Romanoram, p. 52. 2 Mem. of the American Academy of Arts and Sciences, IX. 101. ® Regent’s Reports of the Senate of New York, for 1836, p. 228. # Edinburgh New Phil. Journ. XVI. 35. 5 Iceland or the Journal of a Residence in that Island, I. 357, and Nouvelle Description de ’Islande par Horrebows, trad. de PAllemand. ON THE PERIODICITY OF THE AURORA BOREALIS. 225 for each place or each combination of places at which sufficiently long series of ob- *servations have been made ; and, also, the mean curve for all the observations united. From this mean curve it has been necessary to exclude the occasional observations made in polar voyages, and in very high latitudes. The almost daily frequency of the aurora at such places would unduly inflate the curve for special epochs of observation unless balanced by continuous observation at the same places during the time of at least one secular period. For example: the series of observations on the aurora made at Moose Factory, Cumberland House, Athabasca Lake, Fort Reliance on Great Slave Lake, Fort Enterprise, Fort Confidence, Point Barrow, etc., which furnish from 100 to 150 auroras a year, are necessarily excluded, as the observations continued only two years or less. The unusual activity displayed by meteorologists during the few years that the Me- teorological Society of the Palatinate was in operation put on record a large number of auroras which would otherwise have escaped, and which give an undue preponder- ance to that brief period. Mairan, in his unrivalled discussion of the periodicity of the aurora, has exercised a wide discretion and exhibited the best judgment in the selection of his materials, in- stead of making an indiscriminate use of all :— “ Par exemple, tout pays ou l’arriere-saison et |’Hiver ne preséntent aux yeux de l’Observateur, pendant des mois entiers, qu’un Ciel toujours couvert, qu’un temps pluvieux ou chargé de brouillard, doit étre exclus de nos Comparai- sons et de nos caleuls. Car de semblables pays ne pourroient nous fournir dans cette partie de l’année que quelques grandes Aurores Boréales, et il s’agit ici du nombre plutdt que de la grandeur. Eh quel usage faire en ce cas d’une Comparaison ou l’un des termes seroit si défectueux, et manqueroit quelquefois totalement? Par une semblable raison je rejetterai les observations faites dans des pays trop Polaires et ow le Soleil seroit des jours et des mois entiers sur Vhorizon, dans la saison opposée 4 la précédente; car il n’y auroit encore alors que les trés-grandes Aurores Boréales qui pussent s’y montrer, tandis qu’on en auroit observé un tres-grand nombre d’autres qui auroient paru en Hiver.”? For these reasons Mairan omits the observations made by Croyere in the North of Russia, at Kola, at Kilduin, and on the shores of the frozen sea, two or three degrees beyond the Polar Circle. Satisfactory observations on the aurora have been made only during the last one hundred and fifty years. And even during this choicest period, the number of constant and systematic observers in the field, as well as their station of observation, has varied. Sometimes there have been none; at other times not less than a dozen. These fluct- uations would have affected the mean curve more injuriously were it not for the fact that the zeal of observers died out when the auroras died out, and was rekindled again 1 Traité Physique et Historique de l’Aurore Boréale, pp. 488 and 509. VOL. X. 29 226 ON THE PERIODICITY OF THE AURORA BOREALIS. as soon as auroras became more frequent and more splendid. How much or how little our confidence in the mean curve can reasonably be impaired by interruptions in the * data may be found by comparing the mean curve with the particular curves, for special places, and also by examining to what extent many observers simply duplicate each other’s observations, without adding to the number of recorded auroras. If an exami nation is made of the records of auroras seen since 1700, it reveals the fact that the dis- plays reached a maximum of frequency about the year 1730. The St. Petersburg series agrees with the general table (after excluding cases which fall within Mairan’s ex- ceptions) in assigning the maximum to the year 1730. The miscellaneous observations which Mairan groups under the title of “ Philosophical Transactions of London,” place this maximum as early as 1726, and the Wittemberg series as late as 1742, though there was another inferior maximum in 1731. In Berlin it was the year 1732, in Eng- land, according to Huxham, it was the year 1736, and in Italy it was the year 1737 which claimed the maximum. The series of auroras observed in Sweden discloses one maximum in 1730, and another slightly greater in 1741. This maximum was followed, after an interval of about twenty-five years, by a mini- mum, which, on the average of all the reliable series, belongs to the year 1758. The only four series of observations which extend over this period of time correspond strikingly with each other, as also with the mean. The Cambridge series gives a mini- mum to the year 1755, the Swedish series to the same year, the St. Petersburg set to the years 1753-4, and the observations at Abo to the year 1757. Another sudden and low depression in the year 1766 is worthy of mention. Not a single aurora was ob- served that year either in Cambridge or St. Petersburg. One was seen in England and six at Abo, this secondary minimum appearing the next year at Abo, when only four auroras were observed ; whereas in 1757, the year of the principal minimum, there was one solitary observation at that place. About the year 1787 another maximum is reached. The observations made at Abo, Ratisbon, Prague, Mannheim, and Paris agree separately on the same year as the mean curve gives. The series of Cambridge, Berlin, and Brussels transfer this maximum to the year 1786; those of Jena, Kendal and Keswick, and Sagan, to the year 1788 ; those of St. Petersburg to 1786, though a more decided maximum occurred at that place in the year 1774; the observations at New Haven bring this maximum as early as 1781, but another maximum almost as great is found in the year 1786, whereas those at Stockholm postpone it to 1790. There is a maximum in the series at Montmorenci in the year 1787, but a greater one in 1779; a maximum appears to have come at least as early as 1779 at Carlsruhe. At Copenhagen one maximum occurred in 1787, and a ON THE PERIODICITY OF THE AURORA BOREALIS. 227 greater one in 1782-3. Olmsted’ placed this maximum somewhere between the limits ~ of 1760 and 1783, and Loomis decides that its epoch is about 1780. Ussher? alludes to the greater frequency of the aurora in 1788 as compared with the preceding half century. The mean interval between the two grand maxima which I have described is fifty- seven years. The uninterrupted series at St. Petersburg leaves fifty-six years between the two maxima, the broken series at Berlin only fifty-four years, and the Huxham and Dalton catalogues, combined, only fifty-two years. A second minimum comes along about the year 1812. No aurora was seen in Salem between the years 1810 and 1813 inclusive; nor in New Haven between 1808 and 1813; nor in Great Britain between the years 1809 and 1813. None is registered for St. Petersburg between 1809 and 1823; nor at Abo between 1806 and 1816. During the last one hundred and fifty years the aurora has failed utterly of being registered anywhere on the earth, only in the years 1812 and 1813. A third grand maximum returns in 1849. The Cambridge observations alone post- pone it to the year 1852, and the New Haven observations hasten it on as early as 1847. In New York it was the year 1850; in Providence, 1852; in Newberry, 1853. In Wor- _ cester the principal maximum was in 1840, but there was another in 1848. The short series at Dunse exhibits a maximum in 1843, and that at Makerstoun in 1845. In Christiania there was a maximum in 1852, but a greater one in 1842. In Jakobshavn the maximum of a few years falls upon 1845. The interval between the second and third maxima is about sixty-two years. The Cambridge observations alone imply an interval of sixty-six years, and those of New Haven either sixty-one or sixty-six years, according to the epoch selected for the earlier maximum. There is no other single series which spans the long period between these two maxima, the aurora not being as regularly observed now as formerly at St. Petersburg, and its presence being inferred from magnetic disturbances rather than from direct observation upon the light itself. I have been surprised to see no auroras included in the observations at Sitka in 1853, although there is mention made of many extraordinary magnetic disturbances? Loomis concludes that the average period is about fifty-eight years. Santini‘ sets it as high as sixty-five years. This was also the period which Olmsted adopted. Observations in the Western continent would seem to indicate that the last grand maximum was superior to its predecessor, while the European observations imply the contrary. The multiplication of observers, which explains the first fact, only renders the other more mysterious. Quetelet, who observed at Brussels, adverts to this peculiarity, saying that between 1778 1 Smithsonian Contributions, VIII. 38, 9. 2 Trans. Roy. Irish Acad. 1788, II. 191. 3 Annal. de l’Observ. Phys. Centrale de Russie, 1853, p. 851, &c. * Wochenschrift fiir Astronomie, Meteorologie, &c. 1862, V. 14. 228 ON THE PERIODICITY OF THE AURORA BOREALIS. and 1787 auroras averaged twenty a year; whereas, between 1832 and 1852, there were only two a year, and in 1844 and 1845 none.’ The observations prior to 1700 are so meagre that, instead of taking each year singly, I have made groups of ten years each, beginning with the year 1309. Neglecting the observations made at the close of the seventeenth century by Grebner, at Breslau, about which Forbes himself has great doubts, I can easily select the years 1575, 1625, and 1685, as approximate periods of recurring maxima, the successive intervals from one to the other, and from the last to 1730, exhibiting a rough agreement with the perio- dicity derived from observations of the last one hundred and fifty years. Passing next to still earlier records of the aurora, I may mention the years 585, 675, 805, 845, 995, 1115, 1195, 1355, and 1545 as representing decades in which the number of recorded auroras ran ahead of the average. No weighty conclusion for or against the interval, already assigned to the more recent maxima, can be drawn from these conspicuous decades. For, by varying the interval to any value between fifty-two and sixty-two years, as might be done consistently with the evidence, and then taking a larger or smaller multiple of that interval, any decade whatever could be suited to a maximum. From 1575 back to 1545 is a short interval of only thirty years. . Between 1545 and 1355 there are one hundred and ninety years, which are consist- ent with three intervals, each of about sixty-three years. From 1355 to 1195 are one hundred and sixty years, which will divide into three intervals of about fifty-three years each. Between 1195 and 1115 are eighty years, which might be divided into two inter- vals of forty years each. Between 1115 and 995 are one hundred and twenty years, which may contain two intervals of sixty years. From 995 to 845 are one hundred and fifty years, or three intervals of fifty years. From 845 to 805 there is only one short interval of forty years. From 805 back to 675 are two intervals of sixty-five years. From 675 to 585 are two intervals of only forty-five years. Although the earliest as well as the latest recorded observations of the aurora give unmistakable evidence of the intermittent character of the phenomenon, it is obvious that science must rely exclusively upon the observations of the last three hundred years, and chiefly upon the observations of the last century and a half, for its best deter- mination of the precise interval between successive maxima. Facts as well as analogy favor the suspicion that the interval itself may vary from one century to another, though a variation between forty and sixty years may seem an extravagant supposition. But for the law of this variation, and, indeed, for any certainty as to the fact of the varia- 1 Annales de l’Observ. Royale de Brux. XI. 42. ON THE PERIODICITY OF THE AURORA BOREALIS. 229 tion itself, we must wait for centuries of additional observations, unless some happy generalization, as to the physical cause of auroral displays, shall illuminate and render transparent the obscure and scanty records of the past. When Mairan published the first edition of his Zraité de (Aurore Boréale, in 1733, he pointed out what he supposed to be twenty-two returns (reprises) of the aurora. But his deductions were based on only 229 auroras, all but 59 observed since 1707. Twenty of his great returns were therefore predicated upon only 59 recorded appearances, and were the results of negative rather than of positive evidence. Indeed, in his catalogue, one observation or a small cluster of observations stamped a year as one of maximum frequency, the intermediate years being unrepresented in any record. The intervals between these returns varied from ten to two hundred years. Mairan' made no attempt at discovering a specific interval between the recurring maxima. He says:— “ Depuis le milieu du XI sitcle jusqu’au milieu du XIV™, je ne trouve rien qui puisse étre pris certainement pour VAurore Boréale. . . . . ~ Ce qui donneroit, depuis 1157, une interruption au Phénoméne de pres de 200 ans s'il n’etoit & craindre que ce ne soient seulement les Observateurs et les Historiens qui nous manquent.” And again (page 185), Mairan says :— “ Depuis 1621 jusqu’en 1686, c’est-a-dire, dans l’intervalle de plus de 60 années, je ne trouve aucune observation bien marquée de l’Aurore Boréale, et l’on sait cependant quels Astronomes et quels Observateurs il y a eu pendant ces temps- la. De sorte que l’on peut compter cette interruption du Phénoméne comme une des plus longues, entre celles qui sont le mieux constatées.” In the second edition of Mairan’s work, published in 1754, are added 1441 auroras, of which 302 were prior to 1707. Moreover, between the years 1157 and 1351, where at first he supposed there was a dismal blank, he has collected from other sources four examples, and between the years 1621 and 1686, where he thought there was a per- fect vacancy, he afterwards placed 81 auroras. Indeed, between the years 1622 and 1634 inclusive there are 49 auroras, and the single year 1629 is a conspicuous maximum. If Mairan had revised his reprises, in view of the much larger materials he had in his hands when publishing his second edition, he would no doubt have modified the epochs to suit his enlarged knowledge; but he had no special occasion to reconsider that part of his general subject. Our distinguished foreign associate Hansteen, after noticing the frequency of the 1 Traité Physique et Historique de l’Aurore Boréale, p. 179-83. 230 ON THE PERIODICITY OF THE AURORA BOREALIS. aural about the year 1830, of which he could recall no parallel since the days of his boyhood or since 1793, adds : — “Von solchen Perioden habe ich geglaubt seit dem Jahre 502 vor Christi Geburt bis auf unsere Zeit 24 nachweisen zu konnen, von welchen besonders die neunte, von 541 bis 603, die zwolfte, von 823 bis 887, die zweiundzwanzigste, yon 1517 bis 1588, und die vierundzwanzigste, von 1707 bis 1788 sich durch ungewohnlich starke und hiiufige Nordlich- ter anszeichneten.” Hansteen’s periods of auroral display vary accordingly from sixty-two years to eighty- one years. It does not seem to me, however, that such of the periods as he has speci- fied are those which group the phenomena together most naturally ; and in the case of the twenty-second period, which he makes to begin in 1707 and end in 1788 and cul- minate about 1752, it may be objected that the observations indicate one maximum about 1/30 and another about 1790, and a closer approach to a minimum than to a maximum about 1752. The observations, however, made by Celsius in Sweden, to which, no doubt, Hansteen attached great weight in forming his opinion, are less de- cisive on this point than those made at St. Petersburg or Cambridge. A very cursory glance at the curves which represent the frequency of the aurora from year to year will detect the influence of other periodical fluctuations shorter than the secular one and superadded to it. In the year 1803, Ritter of Jena maintained that the aurora was subject to a periodical variation once in nine or ten years, and that this short period of the aurora was associated with the period of 18.6 years in the . moon’s motion, therefore with the larger nutation-period of the earth’s axis, so much so that the minimum for the aurora corresponded to the largestand smal lest obliquity of the ecliptic, and the maximum of the aurora to each intermediate mean obliquity when the longitude of the ascending node of the moon: was 90° or 180°. From all which Ritter concluded that the connection of the moon with the aurora was unques- tionable. He predicted such a maximum for the year 1806 and another for 18162 I have given in Table LIII. the years of maximum, minimum, and mean obliquities, and also the years of maximum and minimum frequency in the aurora. The latter are printed in capitals, where there is a plausible agreement with Ritter’s theory. Al- though the coincidences between the facts and the theory are in some parts remark- able, the discrepancies are numerous and large: too numerous and too large to be reconciled with the truth of the theory. It may be stated, for the benefit of any one who wishes to pursue the comparison further, that the years 1602, 1611, 1620, 1630, 1 Pogg. Annalen der Physik und Chemie, XXII. 536, 7. 2 Gilbert, Annalen der Physik, XV. 210, 220, and XVI. 226. ON THE PERIODICITY OF THE AURORA BOREALIS. 231 1640, 1648, 1658, 1667, 1676, 1685, 1695, and 1704, are, by Ritter’s supposition, years of maximum for the aurora. Hansteen’ appears to be satisfied with the result of Rit- ter’s prediction for the years 1806 and 1816; and he himself adduces the year 1843 as an additional confirmation of the theory. Fritz quotes from Hislin? to the effect that the latter had advanced a theory similar to Ritter’s as early as 1784. Fritz him- self calls attention to the fact that Ritter’s maxima often concur with those of the solar spots, and that, when they differ, the aurora mounts to at least a secondary maximum in Ritter’s years of mean obliquity, as was conspicuously true of the year 1797. The year 1830, however, is an exception. But Fritz adds, that about this time the Ritter and spot maxima were opposed to each other, whereas, in 1769, 1779, and 1788, the periods of both classes of maxima coincided.? Bickman also had intimated that the great moon-period might determine the recurrence of auroras. TABLE LIIl. Maximum Mean Minimum | Maximum | Minimum | Maximum | Minimum | Maximum | Mininum | Maximum | Minimum Obliquity. | Obliquity. | Obliquity. | Aurora. Aurora. Aurora. Aurora. Aurora. Aurora. Aurora. Aurora. 1717.8 1722.0 1726.6 Upsal. St. Peters’g, Berlin. “Mean. 1731.3 1730 1730 1730-3 1730) +h Means 1736.0 1733-8 1740.6 1741 | Urs | 1742 1742 1741 1745.3 1744 Abo. Abo. 1750.0 St. Peters’g. 1752 1754.6 755 1756 1757 1759.3 1760 1762 1761 1758 1764.0 Berlin. 1765 1768.6 1771 1766 | 1768 1766 1773.3 | Jena &e. 1774 1774 1774 1778.0 1779 1779 | 1779 1782.6 Sweden &c. 1787.3 1786 |Ccambridge.| 1786 | 1791 | 1787 1787 1792.0 1796.6 Paris &c. Salem. 1798 1796 1801.3 1799 1798 1806.0 G. Britain. 1804 |NewHaven.| 1805 1810.6 181] | Carisrune. 1811 1810-5 1812-5 1815.3 Archangel. 1817 Salem. 1820.0 1819 1819 1818 1824.6 G. Britain.| 1823 New York. Abo. 1823 ? 1829.3 | 1830 1850 1830 Abo. 1830 1834.0 1834 1832-5? 1838.6 Norway. 1840 1843.3 1842 Norway. 1840-5) New York. Cambridge. 1844 1848.0 1845 | Newberry. | 1844—5 |Cambridge.} 1843 1849 1852.6 1852 1853 1852 Worcester. | 1857.3 Worcester | 1856 1856 1862.0 1860 1 Nouveaux Mém. de l’Acad, Royale de Brux. XX. 118. 8 Vierteljahrsschrift der Naturforsch. Gesellschaft in Ziirich, X. 230, 258. ? Meteorologische und Witterungsbeobachtungen, Tiibingen, 1784. 4 Gilbert, Annalen der Physik VII. 32. 232 ON THE PERIODICITY OF THE AURORA BOREALIS. In 1851 Lamont! announced the discovery of a fen year period in the amplitude of the diurnal oscillation of the magnetic needle. This discovery reposed on the nice observations which had been instituted at the Magnetic Observatory of Munich. Ten years afterwards” he assigned the length of this periodical change with greater precis- ion, making it 10.43 years. The maxima or minima occur in the following years :— Maximum, 1786.5 | Maximum, 1837.5 | Maximum, 1848.8 | Maximum, 1859.5 Minimum, 1817.0 | Minimum, 1843.0 | Minimum, 1855.0 Sabine ® soon discovered that this decennial period appeared in the observations made between 1843 and 1848 at the magnetic observatories of the British Colonies, viz., at Toronto and Hobarton*®; and was applicable not only to the changes in the amplitude of the diurnal oscillation but to the frequency of the irregular disturbances. Wolf recog- nized the same law in the magnetic observations made in Prague and Kremsmunster. Afterwards, Bache* discussed the magnetic observations made for two or three years at the Girard College, in Philadelphia, and detected traces of the decennial period not only in the changes of the declination but also in those of the horizontal component of the earth's magnetic intensity. : The decennial period is approximately the same for all parts of the earth. Hansteen’® saw it confirmed in his own long series of twenty-five years of magnetic observations at Christiania ; and, with Sabine and Lamont, he extended it to the ielination and the intensity. Hansteen computed the period of the magnetic changes, and found its length to be 11.33 years. Observations on Terrestrial Magnetism are’defective between the years 1798 and 1813, while Europe was disturbed by war. Still, no doubt remains in regard to the fact of a nearly decennial fluctuation. The precise period of the oscillation may be hereafter slightly corrected, and may itself suffer a secular variation. In the mean while Wolf, now of Zurich, was engaged in studying into the laws of - periodicity of the solar spots. He availed himself of the long and faithful observations which Schwabe’ had been making, at Dessau, since 1826. Schwabe himself saw in 1 Sitzungsberichte der Konigl. Bayer. Akad. der Wissensch. za Munchen, 1862, II. Heft Il. 71. Pogg. Ann. der Physik und Chemie, LXXXIV. 572, LXXXV. 412-20, and LXXXVI. ss. 2 Pogg. Ann. der Chemie und Physik, CX VI. 607. Biblioth. Uniy. Archiv. de Nat. et Phys. Sci. XLX. 306. 8 Phil. Trans. Roy. Soc. London, 1851, 2, and 3. £U. S. Coast Survey Reports, 1859 and 1862. Proc. American Assoc. for the Advancement of Science, XIII. 251. 5 Astronomische Nachrichten, XLV. 195. ® Compt. Rend. XXXV. 364. Astronomische Nachrichten, XXXIV. 159 and XXXY. 369. Mittheil. der Berner Naturforsch. Gesellsch. No. 245, p. 183. 7 Astronomische Nachrichten, XXI. 235. ON THE PERIODICITY OF THE AURORA BOREALIS. 233 these observations indications of a decennial period, and pointed out the years numer- ically poorest or richest in solar spots. Wolf changed the length of the period to 11.11 years. Some observations, recently brought to light by Thiele, prove that as early as 1775 Horrebow had a glimpse of the existence of some law of periodicity in the frequency of solar spots.’ Since this first announcement many eyes have watched sedulously the spots upon the sun, and the archives of science have been ransacked by Wolf and his co-laborers for old observations. More than eleven hundred volumes, printed or manuscript, have been searched, and from their pages Wolf? has gathered 23000 observed spots, extending over one hundred and twelve years, between 1749 and 1860. Observations of the solar spots have been accumulated on 22495 days, viz., on 2143 days in the 17th century, on 5490 days in the 18th century, and on 14860 days in the 19th century. From these multiplied materials Wolf has been able to write out an almost consecutive history of the transactions on the sun’s surface from the year 1610 to the present moment. The interval between successive maxima varies between the extremes of 8.2 years and 15.5 years; the same period returning once in 79 or 85 years. The mean length of the period, derived from the minima alone, is 11.17 years; and from the maxima alone 11.02 years. The observations anterior to 1750 require a period of 11.15 years. The great difference between the particular and the mean values of the period made the year 1788 the year of the real maximum, and also the year of the mean minimum. Wolf thinks that there is reason to suppose that unusual activity in the forces which develop the solar spots results also in a diminution of the period between successive maxima.” Table LIV. exhibits the years of maxima and minima which Wolf* has deduced from the materials in his hands, and the intervals between them. He calculates that the formula, — E,, = 1732.823 + x. 11.119, satisfies best the observed minima, on the presumption that the period is constant. But the difference between the calculated and observed years of minima amounts sometimes to more than three years. He substitutes, therefore, for the first formula another, which recognizes the variability of the period itself® : — 1 Astronomische Nachrichten, L. 257. 2 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, VI.175. Biblioth. Univ. Archiv. de Nat. et Phys. Sci. X. 260. 3 Astron. Nachr. LIV. 346. Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, VI.192. Pogg. Annalen der Physik und Chemie, CX VII. 505. * Poge. Annalen der Chemie und der Physik, CX VII. 505. Astronomische Nachrichten, LIII. 338, and LIV. 257. 5 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, III. 136, IV. 215-17, V. 247-250, VI. 188-190, and X. 355-58. VOL. X. 30 234 ON THE PERIODICITY OF THE AURORA BOREALIS. Fj 360° a Ae 360° E,, = 1732.823 + a. 11.119 + 1.621 sin. (146° +2 ara 1.406 sin. [230° + x Pek il: This was afterwards changed to the following : — 3860 360° E, = 1799.455 4 @. 11.1534 1.621 sin. [290° 2 == ] + 1.406 sin. [802° + « ——], = eS n— VD equal to 1.575 years for the periods of minima, and 1.870 years for the periods of Wolf makes the uncertainty in a single epoch by the usual formula, maxima. The uncertainty in the value of the mean period is by the maxima alone equal to .418 of a year, and by the minima alone equal to .336 of a year, according to the usual formula, 7 = Oa TABLE LIV. SS SSS Maxima. Intervals, Minima. Intervals. Maxima. Intervals. Minima. ase | 1610.8 1738.5 11.0 1745.0 11.5 1619.0 8.2 1750.0 11.5 1755.7 10.7 1626.0 1634.0 15.0 1761.5 11.5 1766.5 10.8 1645.0 11.0 1770.0 ° 8.5 1775.8 9.3 1655.0 10.0 | 1779.5 9.5 1784.8 9.0 1666.0 TO wales 9.0 1798.5 13.7 1675.0 1679.5 13.5 1804.0 15.5 1810.5 > 129.0 1685.0 10.0 1689.5 10.0 1816.8 12.8 1823.2 19.7 1693.0 8.0 1698.0 8.5 1829.5 12.7 1833.8 10.6 1705.0 | 12.0 1712.0 14.0 1837.2 Wad 1844.0 10.2 1717.5 12.5 1723.0 11.0 1848.6 11.4 1856.2 12.2 1727.5 10.0 1733.5 10.5 1860.5 11.9 1868.32 Wolf says of his last formula : — “Tmmerhin gebe ich sie nur als einen ersten Versuch, und behalte mir vor, in der Folgezeit, sei es ihre Constanten noch etwas abzuiindern, sei es durch Zuftigen weiterer Glieder ein noch besseres Anschmiegen zu erzielen.” What gave extraordinary interest to these two apparently insulated discoveries, the first in the Physics of the Globe and the second in Astronomy, was the additional one that they were intimately associated with each other, the maximum of magnetic dis- turbance occurring simultaneously with the maximum frequency in the solar spots. This latter discovery was made almost at the same time by Sabine, Wolf, Secchi,’ and Gautier? though Gautier admits that Sabine had the priority in time. With Sabine, 1 Predicted. 2 Arago, Astronomie, II. 180. Pogg. Ann. der Physik und Chemie, CX VII. 503. 8 Biblioth. Uniy. Archiv. de Nat. et Phys. Sci. XX. 189, XXXVI. 185. Also, Bib. Uniy., Nouvelle Period II. 365, and V. 296. ON THE PERIODICITY OF THE AURORA BOREALIS. 235 Secchi, and Gautier the conclusion rested on the comparison of recent observations both of the solar spots and of the magnetic disturbances. Wolf has pursued the subject farther, and coupled with his long list of years numerically rich or poor in solar spots such observations on the amplitude of the diurnal oscillation of the magnetic needle as he was able to hunt up. The result of his investigation is contained in Table LV. In the case of the Declination and the Inclination, the maxima and minima of the magnetic changes coincide nearly with the maxima and minima of the solar spots. But in the variations of the Horizontal component of the Magnetic Force the maxima fall upon the same years as the minima of the solar spots." TABLE LV. Spot Magnetic Magnetic | Spot Magnetic Magnetic Maximum. Maximum. Maximum. Minimum. Minimum. Minimum. Wolf. Wolf. Lamont. Wolf. Wolf. Lamont. 1750.0 1761.5 1755.7 1770.0 1766.5 | 1779.5 | 1775.8 1788.5 1787.2 1786.5 1784.8 1784.5 1796.5 1791.5 1804.0 1803.5 1798.5 1799.0 1816.8 1817.5 1817.0 1810.5 1829.5 1829.7 1829.0 | 1823.2 1823.8 1823.3 1837.2 1837.7 1837.5 1853.8 1848.0 1848.9 1848.8 | 1844.0 1844.2 1843.0 1860.2 1860.0 1859.5 1856.2 1856.3 1855.0 | It will be seen from Table LV. that Wolf and Lamont are not agreed as to the exact times of the magnetic maxima and minima. Wolf maintains that the periodicity of the magnetic changes is the same as that of the solar spots, viz. 11.11 years; while Lamont insists on his original period of 10.43 years for the magnetic fluctuations. Wolf? divides the whole interval between 1786 and 1860 into six periods of very unequal length; Lamont divides the same interval into seven periods of equal length. Hence Lamont has a maximum in 1796.5, and a minimum in 1791.3, the maximum nearly coinciding with Wolf’s minimum of 1798.5. Sabine® concurs with Lamont in thinking that a period of 10 years fits the magnetic movements better than a period of 11 years. Hansteen, on the contrary, deduced from his own observations at Christiania a period for the magnetic inclination and intensity which conformed to Wolf’s period of 11.11 1 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, V. 240, 1; Pogg. Annalen der Chemie und Physik, CX VII. 505-8. 2 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, II. 293, and X. 160. §Magnetical and Meteorological Observations at St. Helena, II. 136. 236 ON THE PERIODICITY OF THE AURORA BOREALIS. years more exactly than to Lamont’s period of 10.43 years, or Sabine’s of only 10 years." Wolf claims that the phenomena of the earth’s magnetism run parallel with those of the sun’s spots not only in their general march but in all their exceptional digressions. Lamont reposes less confidence than Wolf in the earlier observations not only of the sun’s spots but also of the magnetic elements ; and in this opinion the astronomer John- son” appears to coincide. Lamont admits merely a general resemblance without any minute coincidence in the progress of the two classes of phenomena. His words are : — “ Das jedenfalls merkwiirdige Zusammentreffen der Maxima und Minima bei den magnetischen Bewegungen und den Sonnenflecken kann hiernach als ein eigentlicher Causal-Nexus nicht erkannt werden, &c.” 8 Wolf insists that his formula, B=6.273-+ 0.051 a, in which B is the variation in magnetic declination and a the relative number of spots, represents the magnetic observations at Munich, from 1835 to 1850 imclusive, as ac- curately as Lamont’s formula for the declination derived from the observations them- selves, — B=8'.70 + 2/1 sin. [72°.58 + n. 34°.84], (n) being the years elapsed since the epoch, 1848. Wolf afterwards modified this formula, and obtained similar ones for other localities. W. Herschel and Gruithuisen inferred from their own comparisons that an abun- dance of solar spots was accompanied with an increase in the mean temperature of the earth. Arago arrived at the opposite conclusion from observations made at Paris be- tween the years 1826 and 1851. Secchi’s observations in Rome corresponded with Arago’s conclusion. Wolf has renewed the inquiry, and with enlarged materials has sought to reconcile the apparent incongruity here exposed by the fact that between the years 1760 and 1802 the mean temperature was highest in years rich in solar spots, whereas the opposite rule held between the years 1803 and 1847. On this sub- ject a paper by Gautier’ of Geneva may be consulted to advantage. It will be a wonderful fact, whenever it is established, that changes in the number and activity of 1 Bulletin de l’Acad. Royale de Brux. 2 S. VI. 358, 9. 2 Memoirs of the Astronomical Society of London, XXVI. 201. 8 Sitzungsberichte der K6niglich. Bayer. Akad. der Wissensch. 1862, II. Heft II. 74. * Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, IV. 222, 223, WI. 416, IX. 120, and X. 361. 5 Annales de Chimie et de Physique, XII. 57-67; Bibliotheque Universelle, LI. 327. ON THE PERIODICITY OF THE AURORA BOREALIS. Dart the solar spots, which produce none or at most a doubtful disturbance in the earth’s temperature, have written themselves plainly out in the history of the earth’s magnet- ism and of the aurora.’ “* Who would have supposed a few years ago,” asks Wolf, “ that any terrestrial phenomena could have been studied by watching only the spots upon the sun? ” In view of the possible connection between the aurora and the solar spots, the fol- lowing quotation from Mairan? is significant : — “ Et ne pourroit-on point découvrir quelque analogie entre la fréquence, les cessations et les retours des ces Taches et les apparitions, les retours et les cessations de la Lumiére Zodiacal ? “ C’etoit assez le sentiment de feu M. Cassini, ‘ Notre lumiére, dit-il, dans son Discours sur ce Phénoméne, pourroit avoir les vicissitudes qu’ont les Taches du Soleil, qui se forment en certains temps et se dissipent en d’autres; et, c’est une chose assez remarkable, que depuis la fin de l'année 1688, que cette lumiére a commencé de s’affoiblir, il n’a plus paru de Taches dans le Soleil, ou les années précédentes elles étoient assez fréquentes; ce qui semble appuyer en quelque manitre les conjectures exposées aux nombres 21 et 22, que cette Lumiere peut venir du méme écoulement que les Tacheset les Facules du Soleil. . . . Ce qui pardit favoriser cette idée, c’est que depuis cing 4 six ans que les Aurore Boréales, suite ordinaire, selon notre hypothése, des grandes extensions de cet Air, sont devenues si fréquentes, les Taches du Soliel l’ont été aussi beaucoup. On sait encore qu’au commencement du dernier siécle, aprés l’invention des lunettes, on ne voyoit presque jamais le Soleil sans Taches ; et il en avoit quelquefois des amas si considérables, que le P. Scheiner dit y en avoir compté une fois jusqu’a cinquante. Elles devinnrent ensuite plus rares: de maniére que depuis le milieu du siécle jusqu’en 1670, c’est-’-dire, dans l’espace d’une vingtaine d’années, on n’en put trouver qu’une ou deux et qui parurent méme fort peu de temps. Or comme nous l’avons vi, il y eut un grand nombre d’Aurores Boréales au commencement de ce siécle, et jusques au dela de 1621; aprés quoi l’on n’en entend plus parler jusqu’en 1686. Cepen- dant il faut avouer qu'il n’y a encore rien de solide a établir sur cette correspondance apparente, et qu’elle ne se soutient pas toujours également. Car les années qui suivirent 1621, 1622, &c., et ou l’on dit redoubler d’attention pour la Lumiére Septentrionale, purent peu marquées par l’apparition de ce Phénoméne, quoique les Taches du Soleil y fussent en aussi grande abondance que jamais, comme on le voit dans le P. Scheiner.’” In 1831 Littrow® hinted that the northern lights, like the solar spots, submitted to laws of periodicity. Again in 1853, Stevenson‘ cited his own observations on the aurora, made at Dunse, North Britain, as favoring the hypothesis of a minimum in 1843, synchronously with the minimum in the solar spots and the magnetic disturbances. After Fritz had accumulated sixty-three hundred observed auroras, he draws thirteen secular curves, one for the whole year and one also for each month:* in order to compare the maxima and minima of these curves with those of another 1 Vierteljahrsschrift der Naturforsch. Gesellsch. IV. 217-23 ; VI. 182. 2Traité Physique et Historique de l’Aurore Boréale, p. 264. 8 Vermischte Schriften, im Aufsatze ueber das Nordlicht. * Proceedings of the Royal Society of London, VI. 291. 5 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, Jahrgang VIII. 108, 238 ON THE PERIODICITY OF THE AURORA BOREALIS. curve the ordinates of which represent the various richness of the years in solar spots. The most conspicuous maxima of the aurora-curve are in the years 1750, 1769, 1779, 1788, 1839 and 1848: of the spot-curve, they are in the years 1769, 1779, 1787, 1837 and 1848. The principal minima of the aurora-curve are in the years 1758 and 1809- 13: the most decided minima of solar-spots are in the years 1755 and 1810. Fritz thinks it probable that the secular period embraces, on the average, five of the eleven- year periods or 55.55 years. Wolf’ draws a secular curve through the swmmits of the undulations expressing the relative numbers of solar spots, and its maxima appear in the years 1779 and 1837, and its minima in 1816 and 1860. He draws another secular curve through the lowest points of the undulations and the maxima occur in 1775 and 1833-4, and the minima in 1810 and 1856. The long swell is equal to five or six of the short waves. Car- rington* explains the smaller elevation of the summits of the secular curve of the solar spots in the latter part of the last century, when compared with the summits of the present century, by improvements in telescopes or by an increase in the number of observers. The eleven-year period of the spots rides also on the back of the secular curve of the aurora, these subordinate maxima and minima of the two phenomena coinciding. The years 1723, 1733, and 1745, which are known approximately to be spot minima, are also deficient in auroras. Such exceptions as appear in the interval between 1813 and 1820 Fritz explains by the incompleteness of the catalogues, particularly that of the aurora. The interval between the two grand maxima of 1788 and 1839 is fifty- one years; between those of 1750 and 1788 is fifty-eight years. The average of the two intervals is fifty-four and one-half years. If the year 1848 is substituted for the year 1859 as that of the last great maximum, the first interval will be increased to sixty years and the mean of the first and second to fifty-nine years. Although Wolf con- siders the coincidences just mentioned between the spots and the aurora as proving the cosmical origin of the latter, he objects to the theory of Mairan and Olmsted, which would associate it with the zodiacal light and meteors, that such years as 533,765, 1096, 1766, 1799, 1833-4, which swarmed with shooting-stars, are in no way remarkable for auroras. The secular period of the meteors is only 55-4 years. However, five of these periods contain about the same number of years as three of the secular periods of the aurora. Wolf draws a secular curve for the aurora which he calls the European curve. 1 Vierteljahrsschrift der Naturforsch. Gessellsch. in Ziirich. VI. 190, 1. 2 Monthly Notices of the London Astronomical Society, XX. 282. ON THE PERIODICITY OF THE AURORA BOREALIS. 239 The exclusion of the observations gathered in Arctic expeditions makes the anomalous maximum of the year 1821 disappear from this curve. He then draws another curve from the Swiss observations alone, which he thinks conforms still more exactly to the secular curve of the solar spots. He quotes the Swiss Chronicles of Vogel to the effect that in the year 677 the aurora was seen in that country for ten successive nights: so extraordinary an event for that locality that Wolf thinks there can be no doubt that that year was one of the grand maxima. Also, between the years 1560.and 1583 the aurora was seen very frequently. The whole interval between the years 1788 and 1568 contains four periods of fifty-five years and twenty periods of eleven years each. The whole interval between the years 1568 and 677 contains sixteen intervals of 55.69 years, and eighty intervals of 11.14 years each. The long interval between 1788 and 677 contains twenty intervals of 55.55 years, and one hundred intervals of 11.11 years. On the other hand, Olmsted’s period of 65 years would introduce a minimum instead of a maximum into the year 1568. As Wolf’s period is about six-sevenths of Olmsted’s period, the two will concur in making the same year a maxi- mum once in about three hundred and ninety years; for example, in the years 1788 and 1398. Fritz’ argues for another grand maximum in the year 1505 or 1516: but the evidence is far from being conclusive. After Fritz* had extended his catalogue of auroras to eighty-four hundred he arranged them in three separate groups according to the geographical position of the observer, and then compared the number for each year between 1824 and 1861 with Wolf’s rela- tive numbers of solar spots. Though a general parallelism between the two phenomena prevailed, the alternations in the aurora lagged behind the corresponding ones in the solar spots. As soon as Fritz’s’ catalogue of auroras had reached ninety-five hundred, embrac- ing 40000 observations, he again made a table of comparisons between the number of auroras in each year and the relative number of solar spots, extending the comparison to the interval between the years 1700 and 1861: and making it, not only for the observations in the aggregate, but also separately for the auroras observed in distinct zones of latitude. He finally settles down upon the years 1730, 1788, and 1848, as those of the grand maxima, and the years 1700, 1758 or 1766, and 1811 or 1812, as the years of the grand minima. The secondary maxima and minima which he de- duces from those series of observations which he considers most complete are ex- hibited in Table LVL. 1 Vierteljahrsschrift der Naturforsch. Gessellsch. in Ziirich. X. 162. 2 Vierteljahrsschrift der Naturforsch, Gessellsch. in Ziirich. IX. 122 8 Vierteljahrsschrift der Naturforsch. Gessellsch. in Ziirich. X. 232-5. 240 ON THE PERIODICITY OF THE AURORA BOREALIS. ‘ TABLE LVI. Maximum. Mean. Period. Spot Maximum. Minimum. Mean. Period. Spot Minimum. 1707 1707 1706 1700 1698 1719-23 1721 . 14.00 1718 1714 14.00 1712 1726-30 1728 7.00 1728 1724 10.00 1723 1755-41 1738 10.00 1739 1733 9.00 1733 1747-52 1749 11.00 1750 1745 12.00 1745 1759-61 1760 11.00 1761 1758 13.00 1755 17691 9.00 1770 1766 8.00 1766 1779 10.00 1779 1776 10.00 1776 1788 9.00 1788 1785 9.00 1785 1802-5 1804 16.00 1804 1796 11.00 1799 1814-19 1816 12.00 1817 1811 15.00 1811 1829 or 1830 14.00 1830 1823 12.00 1823 1837-41 1839 9.00 1837 1834 11.00 1834 1848 9.00 1848 1842 8.00 1844 1859 11.00 1860 1856 14.00 1856 10.90 11.14 Adopting 55.6 years as the mean secular period, and moving backward from the year 1788, Fritz calculates the average years of the earlier grand maxima, and then compares them with Mairan’s Reprises, which were deduced from old recorded observa- tions. The results are given in Table LVII. TABLE LVII. No. Mairan. Fritz. Period. No. Mairan. Fritz. Period. 1 400 399 12 1157 1177 2 450 455 56 1153 1351 1344 167 3 502 511 56 14 1461-65 1455 111 4 560-600 566 55 15 1520 1511 56 5 770-75 788 222 16 1554 6 859 844 56 17 1560-64 i. 900 899 55 18 1574-75 1566 SH) 8 990 1011 112 19 1621 1622 56 9 1039 1066 55 20 1686 1677 5d 10 1098-1104 21 1707-10 \ 11 1116 1122 56 22 1716-32 1733 56 | After confessing and explaining away, as far as possible, some discrepancies and inconsistencies revealed by these comparisons, Fritz concludes with the following proposition :— “« Dass fiir das mittlere Europa das Nordlicht eine periodische Erscheinung ist, deren Perioden einer mittleren Linge von 55.6 Jahren entsprechen, welche in ihren Stiirken jedoch wieder grosseren Perioden unterworfen sind ; dass die grdsseren Perioden von 55.6 Jahren wieder in untergeordnete von etwa 11.11 Jahren zerfallen, und dass 1 Mit einer nachfolgenden Erhéhung von 1774, so dass man in Mittel auf 1771 kame, p. 241. ON THE PERIODICITY OF THE AURORA BOREALIS. 241 endlich das Nordlicht in einem innigen Zusammenhange und parallalen Gange mit der Sonnenfleckenbildung steht und zwar in der Weise, dass zur Zeit der reichsten Fleckenbildung das Nordlicht am hiufigsten auftritt und umgekehrt die Minima Zusammenstimmen und dass, wihrend bei den Sonnenflecken die Hauptmaxima sich weniger auszeichnen, dies bei den Nordlichtern weit entschiedener der Fall ist1.” Herschel’ pays a just tribute to the magnitude and the value of these researches of Wolf and Fritz and recognizes the fact that the secular period of fifty-six years suits the observations upon the aurora better than that of sixty-five years. If the isochronism supposed to exist between the disturbances of the sun’s atmos- phere, the fluctuations of terrestrial magnetism, and the displays of the aurora were satisfactorily demonstrated, the question naturally arises which of the three is cause and which is effect, or whether all three are not independent effects of some general cause. The spots upon the sun have been called mirrors in which the reflex influence of the planets upon that luminary could be seen. An English writer, Grey, has said that he called upon a friend to ascertain by computation whether there was any pe- riod in the movements or conjunctions of the heavenly bodies which could throw light on the eleven-year period of the solar spots. His friend responded that Mercury and Venus would come into conjunction with each other on the same side of the sun once in every 11.08 years. Reichenbach has alluded to the fact that Jupiter’s period is nearly equal to the spot period, and that the maxima of solar disturbance approximate to the times of Jupiter’s passage through the aphelion* If there is an annual periodicity in the frequency of the sun’s spots, suggesting the earth’s variable action upon the sun at different seasons of the year, may not the other planets also exert a similar influence. Wolf has asked and answered this , question. Expressing the comparative influence of a planet over the sun by 3, he computes the following weights as exponents of the activity of the most important planets in this direction : — Mercury = 0.47 Mars = 0.06 Uranus = 0.04 Venus = 1.68 Jupiter = 12.53 Neptune = 0.04 Earth = 1.00 Saturn — 1.12 The ordinate of the curve which represents the disturbance produced upon the sun’s surface by these planets is calculated by this formula : — M =A + B (1.68 sin. 585°.26t + 1.00 sin. 360°t + 12.53 sin. 30°.35t + 1.12sin. 12°.22t). 1 Vierteljahrsschrift der Naturforsch. Gessellsch. in Ziirich. X. 258. 2 The Quarterly Journal of Science. I. 229. 3 Phil. Mag. Fourth Series, XX. 246 and 271. 4 Amer. Journ. Sci. Second Series, XXV. 296. VOL. X. 31 242 ON THE PERIODICITY OF THE AURORA BOREALIS. The constants A and B are computed by the method of least squares and found to be 50.31 and 3.73. This formula gives results which exhibit a rough agreement with the relative number of solar spots observed between the years 1836 and 1839, but the discrepancies between the conclusions of theory and observation, which are great in- deed for the whole interval between 1850 and 1858, are enormous in the years 1834 and 1835. The period of Jupiter, which is 11.86 years, enters largely into the calcv- lated disturbance, but this alone fails to explain satisfactorily the periodicity of the solar spots, the duration of which is 11.11 years. It is intimated by Wolf that the tropical revolution of Jupiter may possibly match the period of the solar spots ex- . actly, since the great oblateness of that planet must produce a large amount of precession in the equinoxes. But he decides that the observations of the sun’s spots are better satisfied by his period of 11.11 years than they can be by Jupiter’s period of 11.86 years, or Lamont’s period of 10.43 years; the first period being nearly the mean of the two other periods.’ The term in the formula which comes next in importance to that of Jupiter is one depending on the mass and distance of Venus from the sun. The period of this term is 7.65 months; and it causes, as Wolf supposes, the subordinate swell in the annual curve of solar spot frequency, the period of which is about .637 of a year. If the solar spots are in any way associated with the aurora, this almost semi-annual period may correspond to that portion of the second terms, in the formulas given on page 211 of this memoir, which cannot be explained by differences in the duration of daylight. De la Rue” has endeavored to obtain evidence of planetary influence on the be- havior of the solar spots by measuring their area under different exposures. He finds changes depending on the variable configuration of the heavens, Jupiter exercising a ’ great though not a predominating influence. The period of about twenty months which he deduces from the observations, points to Venus as the most influential planet, this period being not unlike the time of the synodical revolution of this planet. The possible dependence of the spot-periods on the united influence of all the planets has been discussed by Schmidt* with this result, — that the periods of max- ima concur with the times when the centre of gravity of the solar system is in the surface of the sun, and the periods of minima with the times when the centre of 1 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, II. 358, IV. 73 and X. 151. 2 Researches in Solar Physics, Second Series, p. 42, 3. 3 Resultate aus eilfjahrrigen Beobacht. neber Sternschnuppen. ON THE PERIODICITY OF THE AURORA BOREALIS. 243 gravity is farthest removed from the surface, either inwards or outwards. Peters’ refutes the proposition, by introducing Neptune into the account in calculating the position of the centre of gravity. Dove has found traces of a decimal period in the fluctuations of the mean annual temperature of the earth” Kluge deduces from his own investigations the conclu- sion that a period of about 11.11 years governs the frequency of volcanic eruptions and earthquakes, but in such a way that the minima of these outbreaks occur in years most distinguished by an abundance of solar spots and frequent magnetic disturbances.* 1 Astronomische Nachrichten. 2 London Atheneum for 1866, p. 236. 3 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, [X. 266 and X. 252. SECOND GENERAL CATALOGUE OF AURORAS. Bao - 1128. Nov. 25. Bohemia? Strnadt.? 434. Short. 1130. Jan. 13. Bohemia? Strnadt. 176. Short. ZB | “© Sept. 2. Bohemia? Strnadt. 159. Short. | © Oct. 8. Bohemia? Strnadt. 87. Short. 1132. Jan. 21. Bohemia? Strnadt. 84. Short. | 1138. May 18. Bohemia? Strnadt. ASD: | © Oct. 13. Bohemia? Strnadt. 551 ? Westminster. Matthew, Pensey.? « 14. Bohemia? Strnadt. 590. Short.® 1139. -March14. Bohemia? Strnadt. 610. Oct. 20. China. 1177. Noy. Short. 793. Short. tee | Dec: Short. 905. April 12. | 1189. Short. 978. Short. — 1193. England.? 992. Oct. 26. Zurich? Vogel, Wolf.* 1194. England. 1097. Maier, Frobes ?° 1347. Short. 1117. Feb. 17. Hinsiedeln. Kuhn.‘ 1460. Jan. 13. Bohemia? Strnadt. 1122. Short. 1560. Dec. 28. Mark, Brandenburg. Beckmann. : 1562. March 23. Rauner.* 1A General Chronological History of the Air, Weather, &c. rs IL 178. 1564. Short. 2 Annals of Philosophy, IX. 250. « Feb. 15. Scotland.§ 3 The Aurora was seen on three nights. a 18. Scotland. Vierteljahrsschrift der Naturforsch. Gesellsch. in Zurich, IT. 1 Chronolog. Verzeichn. d. Naturgebenhen in Béhmen. 83 and 401. 2 Neubrigensis Chronica Rerum Anglicarum, IV. 36. 5sRobert Monachi Historia Hierosol. Lib. V. Comm. Acad. | 8Wochenschrift fiir Astronomie, Meteorologie, &. Neue Folge, Scient. Petrop, 1726, I. 366. VII. 280. 5 Vierteljahrsschrift der Naturforsch. Gesellsch. in Zurich, XI. 4 Wolf quotes Chasma Coeli, Erffurdt. 112. If this date is in old style, the Aurora may be the same as 5 Burton, in his History of Scotland, refers to Knox’s History, that of Feb. 22. Il. 417. ON THE PERIODICITY OF 1571. Aug. 4. London.* 1572. Jan. 28. Bohemia? Strnadt. 1574 Short. 1575, Vindemia. Maier, Frobes. *1575. Oct. 8. Aarberg. Liithardt, Wolf. 1603. Feb. 7. Bohemia? Strmadt. “ March13. Meyenfeld. Basler, Wolf. « Aug. 6. Zurich? Vogel, Wolf. 1604. Dec. 7. Meyenfeld? Basler, Wolf. a “ 19. Bohemia? Strnadt. 1607. Feb. 23. Zurich? Vogel, Wolf. *1621. Feb. 3. Mairan, Wolf.* ease Sept. 12. Zurich, &c. Basler, Wolf.® 1637. Aix. Gassendus, Frobes. iy Occitania. Duhamel.® 1646. Feb. 6. Mark. Beckmann. 1658. Oct. 13. Mark. Beckmann. 1678. Oct. 29. Mark. Beckmann. 1680. May 31. Kirch,’ Wolf. *1704. Dec. 28. Copenhagen. Happel.® *1707. Feb. 12. Copenhagen. Romer,’ Liebknecht. * 6 se 12. Wollfius, Weidler, Reuss. * « Marech17. Schomberg. Seidelius. ete “ 17. Copenhagen. Romer. mc « 18. Berlin. Kirch, Leibnitz.” x “ 20. Tornea, Bothnia. Scheller. * « Aug. 16. Breslau. Happel. ti “ 17? Breslaw. Happel. ae Oct. 27. Tornea, Bothnia. Scheller.™ * «& Noy. 24. Tornea, Bothnia. Scheller. Ee ce ce 20. ieuss: *1708. Aug. 20. Thompson and Pilgram. 1«_the Londoners were in the streets gazing atahugearchin the sky, which seemed to span the city, and filled their hearts with terrors of approachmg change.’—Fronde’s History of England, X. 258. 2 He quotes Marcellus Squarcialupus. 8 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, I. 197, V. 327. 4Wolf quotes Mairan, and Mairan quotes Kirch. the Aurora of March 3? Compare Mairan. 5 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, IV. 389. 6Opera Philos. Tom. I. Lib. de Meteoris L. I. Cap. IV. p. 327. 7 Wolf quotes Neue Himmelszeitung. 8 Denckwurdigkeiten der Welt. 8 Miscellan. Berolin, I. 131, 133, et 135. 10 Comment. Hist. Acad. Reg. Scient. Paris, 1707. Is this not 11 Pisput. de Chasmate sive Aurora Boreali, p. 18. THE AURORA BOREALIS. *1708. Aug. 21. Thompson. * « Sept.15. Pilgram. * « Sept. 22. Leipsic, Naumburg, and Zeitz. aS « 22. Jena and Halle. Wollfius.) *1709. Oct. 18. Durham, England. * « Dec. 19. Marienburg, Prussia. 1710. May 29. Leeds. Thoresby.* id UC Dec. 7. Giessen. Liebknecht.’ *1711. Marcha. Brisach. Frobes.* *1714. Oct. 15. Berne. Frobes. [Probably a me- teor ]. 1716. Feb. «. Upsal. Frobes.2 [Omitted by Mairan. } is March 16. Mark. Beckmann, Wolf. pa “ 17. Noreéping. Oxelgren.® op MG “ 17. Reuss, Pilgram. te “ 17. Prussia. Pater. su “ 17. Leipsic. Gemynius.? ear “ 17. Helmstédt. Wagner shat “ 17. Brunswick.' on “ 17. Halberstadt, Halle. Fe Oh “ 17. Saxony. Wollfius. et “ 17. Lomme. Schmidems. “3 “ 17. SHisleben. Boetticherus. ee “ 17. Giessen, Hessen. Liekbknecht. , ae “ 17. France and G. Britain. aa ee « AT. Weidler: “ March 24. Switzerland? Scheuchzer. Wolf.* * « April 11. Paris. Cassini, Reuss. zB <2: Paris) Gassini: PM « 3. Paris. Weidler.* * « May 1. Giessen. Liebknecht. Reuss.” x 6 2. Giessen. Liebknecht.” 1 Acta Erudit. Lips. 1708, p. 526. 2Phil. Trans. XX VII. 322. It is doubtful whether this was an aurora, though Thompson so regards it in his Meteor ology- 8 Acta Erudit. Lips. 1711, p. 325. 4Acta Phys. Med. Artific. Litt. Uratislav. 1717, I. 165. 5 Acta Litt. Sueciae, I. 568. 6 Celsius, Observ. de Lumine Boreali, p. 1. 7Kurze Bescreibung der Neuen Wunder-Erscheinung des Nord-Lichts, &c. 8 Acta Erudit. Lips. 1716 pp. 357, 361, and 365. 9Naturhistorie des Schweizerlandes. 10 Mém. de l’Acad. Paris, 1716, p. 122. 11 Was not this a meteor? 12Syrmatum et Coruscationum Borealium in Horizonte Gisseno obsery. Descriptio. ON THE PERIODICITY OF THE AURORA BOREALIS. *1716. May 3. Giessen. Liebknecht. Paes sf 4. Giessen. Liebknecht. cemc ue 5. Giessen. Liebknecht. mG: Dec. 15. Paris. Maraldi, Reuss. rants cs 16. Paris. Maraldi, Reuss. “1717. Feb. 16. Reuss. [Also Jan. 6,9,10,and 11. ] PS Aprile Gh eiar7s..e) Ware die Panes Me 9. Paris. Maraldi, Reuss. ge: “ 40. Paris. Maraldi, Reuss, Weidler.} zeae Tie) Paris: Maraldi, Reuss. * « Aug. 21. Silesia and Lusatia. Fisher. iT sce o 21. Polen, Prussia, and Hungary. EP 6 us 21. Gottschling.® “Sh Sept. 20. Reuss. > Oct. a. Upsal. Burman.4 *1718. Feb. 5. Marseilles. Gemynius.5 woes “14. Sehyllberg, Nericia. Hiorter. * « March 4. Schyllberg. Hiorter, Reuss. meas’ “« 4. Bohemia. Gemynius.® ee te “ 4. Copenhagen. mvs’ “« 4. Mark. Beckmann, Wolf. BA ots “ 15. Silesia and Prussia. Frobes. ete “ 18. Schyliberg. Hiorter. ct A “ 19. Mark. Beckmann, Wolf. uate PS oneal, letinge) ay, ase “ 22. Zurich. Kirch. A) 56s April 2. Bohemia? Frobes. * & May 11. S¢. Martin, Antillas.7 Frobes. * ¢ June 8. Ohlau. Frobes. * « Aug. 28. Schyllberg. Hiorter. * «“ Sept. 16. Schyllberg. Hiorter, Reuss. a “ 16. Mark. Beckmann, Wolf. * “ Oct. 11. Schyllberg. Hiorter. mye’ « 23. Reuss. Hy pte « 27. Schyllberg. Uiorter. * « Noy. 2. Reichstadt, Bohemia. Rost. * 6 “ 23. Mark. Beckmann, Wolf. FS Deca alin wiles, oe “ 18. Schyllberg. Hiorter. 2G « 30. Schyllberg. Hiorter. os “« 31. Germany. Frobes. 1 Acta Erudit. Leipsic, 1717, p. 270, 1721, p. 188. 2 De Insolito quodam Phoenomeno Kesmarkini &c. viso. 2 Meteorologia Sacra. 4 Acta Litt. Sueciae, I. 566. 5 Gedancken uber den zu Leipsic, &c., entstandenen Nord- schein. 5 Acta Uratislav. 1718, p. 670. 7 Acta Phys. Uratislav. 1718, p. 810, 999, 1077, and 1961. *ITLO Keb. 23. ace March 5. * % (7 5. * 66 “ 5. * 6 “ 6. * 66 73 30. LS s\oval. ||) nn “ 9. * 6 “ 10. * 6 “ 10. * 6 “« 18. * © Sept. 25. #1 60d Jet * 6 “ 30. a Nov. 2. * 6 6 14. * 6 3 17. * 6 “c CAL * 6 6 oy * 6 “ 94. * 6 6 24. oc Dec ie (3 ‘ g. * 6 “ 92. *1720. Jan il Kin iee 6 als ee Feb 6. * 6 6 6. * “ “c 10. * 66 6c 10. * 6 “ 11. “ 6 18. * 6 ‘“ OD) * 6 13 26. gps March 9 wiiGs Nov. 29. Poe Met CC mame: t3 “cc 6. * “ it 28 245 Marseilles. Hermann.t Switzerland. Scheuchzer. Bohemia, Silesia, Saxony. Franconia, Schwabia, Italy. Marseilles. Hermann. Whiston, Reuss.? England, Belgium. France. Frobes. England, Belgium. France. Frobes. Paris. Frobes.® Lithuania. Frobes. Berlin and Magdburg. Frobes Bohemia and Silesia. Frobes. Appenzell. Scheuchzer.* Reichstadt, Bohemia. Frobes. Marseilles. robes. Reuss. Madgburg. Frobes. Bohemia, Silesia, Saxony. Marchia. Magdburg. Frobes. Frobes, Halley, Weidler.® Reuss. Gothia, Sweden. Celsius. Paris. Maraldi, Louville, Reuss.® Mark. Beckmann. Paris. Maraldi, Reuss. Mark. Beckmann. Paris. Maraldi, Reuss. Mark. Beckmann. Tiitzen." Berlin. Reuss. Marseilles. Frobes, Reuss. Corsica. Frobes. Saxony, Lusatia, and Polonia. Reuss. Gardell. Kirch.® 1 Acta Uratislay. 1719, p. 177, 316. 2 Acta Erudit. Leipsic, 1720, p. 218. 3 Acta Erudit. Leipsic, VIII. 465, Suppl. IT. 55, 338. 4Frobes thinks this appearance may have been a fragment of a parhelion. 6 Aurora Australis. 6 Acta Erudit. Leipsic, 1727, p. 499. 7In the original Lucinwn. 8 Acta Uratislav. 1720, Pt. I. p. 184, Pt. II. p. 450. etc. “ “ ee ee He we he me me Re Om mm “ * _ y bo bo ek eee KH HK OH HO HO RO 1 Wochenscrift fiir Astronomie, Meteorologie, etc., Janse Feb. 17. cere “28. 923! io 28: 28. March 1. cca es “ 29. Oct. 3. 43 23. 2. B © 31. Noy. 1. Jan. 22. a 23. 2D. Feb. 23. « 24. ui 27. March 17. cS: rail April 5. May 23. June 4. Sept. 16. CET ale tales Oct. 14. « 19. ie 20. te Zh. “ 2b: Ke 26. Noy. 14. ‘% 22. > 5 235 Us 24. Folge, II. 294. 2 Acta Erudit. Leipsic. 1721, p. 157, ete. | 3 Gott. Gelehr. Zeit. 1721 pp. 710-33. | * Acta Uratislay. 1721, p. 177, 802, ete. 5 Luzinensibus, or inhabitants of Liitzen. § Acta Uratislay. 1722, Pt. I. p. 49, ete. T Novellae Litter. Lips. 1728, p. 220. ON THE PERIODICITY OF THE AURORA BOREALIS. Heis. France. Maraldi, Reuss. Germany. Liebknecht.? France. Maraldi. Germany. Leibknecht. France. Miraldi, Heis. Germany. Liebknecht. Mark. Beckmann. Germany. Kulm, etc. Wittemberg. Hallmann.? Stuttgart. F robes.’ Magdburg, Nuremberg. Rost. Liitzen,> Dresden, Poland. Liitzen, Dresden, Poland. Nuremberg. Magdburg, Nuremberg. Rost. Nuremberg. Rost.® Nuremberg. Rost. Nuremberg and Breslau. | Seehausen. Siegesbeck.® Seehausen. Siegesbeck. Seehausen. Siegesbeck. Angerburg. Frobes. Breslau. Frobes. Nuremberg. Rost? Seehausen, Dresden. Frobes. Lobau. Frobes. Jauer. Frobes. Saxony. Frobes. Seehausen. Siegesbeck. Saxony. | Seehausen. Siegesbeck. Seehausen. Siegesbeck. Dresden. | Seehausen. Siegesbeck. Seehausen. Siegesbeck. Seehausen. Siegesbeck. Seehausen. Siegesbeck. Seehausen. Siegesbeck. | Seehausen. Siegesbeck. Giessen. Liebknecht.” | Dresden. F robes. Dresden. ¥ robes. Neue | | * * *K Ke * KK KK KH HK KX * given by Mairan. “ “ *¥1722. Dec. 3. Ys 12. “ 15, Ke 3. Jans) aliZ, a: 14. “ 17. March 10. bs alts Sept. 7. Sera: Ke euzS: Oct. 31. Dec. 18. Jan. 17 cc 29. 305 March 24. May 4. “« 22 Aug. 4. eat} mealie e oboa: aye a Sept. 9. i p22: 6 23: Dec. 25. Jan. 8. “ 8; Ke 9. Cy 2. : 13 — NP MUoOHAMH ON. Dantzig. Kulm. Dresden. Frobes. Seehausen. Siegesbeck. Pilgram. Nuremberg. Seehausen. Siegesbeck. Frobes.* Frobes.? Frobes. Frobes. Frobes. Frobes. Lusatia, Saxony. Jauer. Frobes. Germany, Poland, Italy, France.* Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Germany, Poland, Italy, France. Tornea. Burman. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Portugal. Giessen. Breslau. Jauer. Jauer. Jauer. Frobes. Upsal. Burman.* Upsal. Burman. Upsal. Burman. Germany. Frobes. Germany. F robes. Germany. ¥ robes. Germany. robes. Germany. Frobes. Germany. Frobes. Germany. Frobes. 1 Uratislay. 1723, p. 71, and Suppl. 11.57. This aurora is not Perhaps it was a meteor. 2 Novellae Litter. Lips. 1723, p. 220- 3 Acta Uratislay. 1724, p. 70, ete- 4 Acta. Lit. Sueciae, II. 141. *tijzoure Dee. ois 1726. Jan. 4, ay Feb. 7. ds March 17. “ “ 81. KG i ONL. paancs Sept. 5. * “ce “ Des) Pn Octs Uc se se uh say’ ee 14, +3) ue 15. te se 19. ad ue 19. * ¢ ““ 19. * c “c 19. * ‘ “ 20. * “ce 73 D1. SU Nov. 4. eens Dec. 1 * oe “ 18. 2. | dant, aL! ch Gs March 14. * T7 cc 15. oh Se Ayoutl | ate * “ “cc 14. eo hee AUCs ile A Sepia 22. ee _ Oct.’ “13: * 4c (T3 14, * “ “ Te a ee Eis * “ “ 19. * “ “cc 20. be i 23. ey eNiove 6. 1728. Feb. 9 * “ “ 9, *€ “ “ 9, * (73 “ 9, * “ “ 9, * “ “ 9. x 6 “ 9. * “ “c 13: x 6 “ 26. ON THE PERIODICITY OF THE AURORA BOREALIS. Germany. Frobes. Reuss. [Old Style ?] Germany. robes. Coast of Spain. Rico. Reuss. {Old Style ?] Germany. F robes. Germany. Krobes, Germany. Frobes. Reuss. Mark? Beckmann. Pilgram. Pilgram. Spain. Rico, Reuss, Pilgram. Helmstadt, Germany. Frobes. Poland, Switzerland. France, England. Germany. Frobes. Germany. Frobes. Lund, Sweden. F robes. Germany. F robes. Germany. F robes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. F robes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Italy. Manfredi. Germany. Frobes. Germany. robes. Cola. Croyere. Germany. robes. Kesmark, Hungary. Buchholz. Germany. 'Trautmann. Seehausen. Siegesbeck. Dantzig. Kulm. Nuremberg. Rost. Helmstadt. robes. Utrecht. Musschenbroek. Hudiksvall. Germany. Frobes.° Bromann. 1 Mem. Acad. Ciencias Madrid, III. 77. 2 The aurora was seen at Mark in 1728 seventeen times. 3 Those auroras seen in Germany this year were seen as specified for Feb. 9. *1728. Feb. * « March 26. * “ “c Qe sate ce 29. SUS PA ralinneae * 66 “ 4, NED Ahi. 66 * “ “ 25. « duly 28. mS | Auge 30: * “c “ 30. en Septameane * 66 “ 29. ss GB Oa a * (73 (73 DE * “ “ 9: * “ “ 4, * (73 ““ 7. * & “ 24. a eNO VAns meee * 73 “ce on we WU) Ore 4. * 6 “ 14. *1729, Jan. 17. * 6 “ 20. * its “ 24, sai Feb. 16. * 6 “ 47, co March 2. x Gh Oe w GP p\pail Gh * 6 G Flt * iT “ 80. SO eye ale * “ “ perl x “ 29, * 6 “ 81. ee yune wale * 66 GB Ue, PAN S29) Se Sepia: x “ 99. |* « Oct. 11. 29. Frobes. Buechner.! Buechner. Frobes. Frobes. Frobes. Frobes. Frobes. Germany. England. England. Germany. Germany. Germany. Germany. Germany. Plymouth. Huxham. Germany. F robes. Lobau. Wehr. Russia. Frobes.* Germany. Frobes. Germany. Frobes. Reuss. Utrecht. Musschenbroek.*‘ Lobau. Wehr. Germany. F robes. Germany. Frobes. 247 Reuss. [Old Style ?] Germany. robes. Germany. F robes. Germany. Frobes. Germany. F robes. Germany. Frobes.® Germany. F robes. Germany. robes. Germany. Frobes. Germany. Frobes. Germany. robes. Germany. robes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. robes. Paris. Maraldi. Lébau. Wehr. Germany. F robes. Paris. Maraldi. Paris. Maraldi. Kraft. Paris. Maraldi. Risinge, Sweden. Laurel. Germany. Frobes. 1 Miscellan. Phys. Medic. Math. 1728, p. 924, ete. 2 Gilbert. Annalen der Physik, XXXII. 336, ete. 8 Comment. Petrop. IV. 121. 4 Tabula Meteorologica, 1728. 5 Biichner. Miscell. Phys. Med. Math. 1729, pp. 40, 100, etc. 6 Parish near Nincoping. 248 *1729. Oct. 13. * 6 “ ee * « “ 94, PE AN Ay UG * «& “ 16. * 6 “ 16. * 6 © dig: Dec elite *1730. Jan. 16. “8 Us Feb. 7. x 6 “ 15. : ‘“ 15. * & “ 16. * 6 “ is: + < + March) 6: * « “ 6. * & “ 9. * 6 “ 9. * « “ ive * 6 “ ‘LS! * « — April 12. * Sie ea (St * « “« 90, ee May meso: * ¢ June 21. eee uly ros * 6 “ 6. * 6 oe Aga * & “ 19. Se Age * « Sept. 28: * & “ 380. * « “ 30. ee Oct y ane * 6 “ 5. * 6 “ 6. * 6 “ i (a * «& “ 9. * « “ ne * « “ 90. * & “ D1. * & “ 92. “ “ 24. * « “ 26. vam Oyen eae x & “ 2. m3 “ Gy 1 Buechner. Miscell ON THE PERIODICITY OF Paris. Maraldi. Germany. Frobes. Germany. Frobes. Germany. Frobes. Reuss. Paris. Maraldi. Risinge. Laurel. Hudiksvall. Bromann. Inunda. Quenselius. Germany. Frobes. Germany. Frobes.+ Germany. Frobes. Germany. Frobes. Reuss. Thompson. Germany. F robes. Germany. Frobes. Germany. F robes. France. Reuss. Germany. F robes. St. Petersburg. Kraft. Germany. Frobes. Germany. Frobes. Germany. Frobes. Lusatia. Germany. Frobes. Germany. F robes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Lébau. Germany. Frobes. Germany. F robes. Siam. Frobes. Germany. Frobes. Germany. F robes. Risinge. Uaurel. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. Frobes. France. Germany. Frobes. Germany. Frobes. Germany. Frobes. Germany. Frobes. Reuss. Pilgram. Germany. Frobes. Mark. Beckmann. Germany.. Frobes. Pilgram. France. Frobes. . Phys. Med. Math. 1730, pp. 824, ete. THE AURORA *1730. Nov. * « “ * « “ * 6 “ * “ eS Dace * 6 “ * 6 “ * 6 “ * « “ ALTol.. ‘Oct: * «& “ * 6 ‘“ * 6 “ * 6 ‘“c * 6 “ * & “ * “ ‘ eke § Nowe *1732. Jan * “ec “ es means * & “ * « Mar. * « “ * & ‘ * 6 ‘ * 6 “ce * 6 “ te June we Aug. * “ “ * «< ‘Sept * 6 “ * 6 ‘ * 6 3 * 6 “ 2A 63 Oct. et Noy. * ¢ “ Dec *1733, April ae July *1734. Sept. BOREALIS, 5. Germany. Frobes. Pilgram. 7. Germany. Frobes. 8. Germany. Frobes. 19. Germany. Frobes. 28. Germany. Frobes. 8. Germany. Frobes. 17. Germany. Frobes. 23. Germany. Frobes. 26. Germany. Frobes. 28. Germany. Frobes. 3. Helmstadt. Frobes. 4. Helmstadt. Frobes. 7. Hiudiksvall, Sweden. 7. Helmstadt. Frobes. 8. Helmstadt. Frobes. Thompson. 8. Mark. Beckmann. 23. Helmstadt. Frobes. 29. Helmstadt. Frobes. 11. Helmstadt. Frobes. 3. Hudiksvall, Sweden. 18. Hudiksvall, Sweden. 20. Germany. Frobes. 21. Germany. Frobes. 14. Germany. Frobes. 18. Germany. Frobes. 21. Germany. Helmstadt. Frobes. 22. Germany. Helmstadt. Frobes. 28. Strengnesia, Hanestroem. 28. Ollonberg. 26. Germany. Helmstadt. Frobes. 22. Germany. Frobes. 23. Germany. Coburg. Frobes. 10. Germany. Frobes. 23. Germany. Frobes. 24. Germany. Frobes. 25. Germany. Frobes. 26. Germany. Frobes. 23. Germany. Helmstadt. Frobes. 12. Germany. Frobes. 20. Germany. Frobes. 4, Mairan.? 13. Silesia. robes.’ 7. Leipsic. Gottsched. 19. Altorf. Kelschius. 1 Condamine, while making a journey from Cyprus to Con- stantinople, saw the aurora frequently in Sept. and Oct., 1721. 2 Mém. de l’Acad. 1733, p. 478. ; Lips. 1733, p. 291, etc. 3 Noya Litter. ON THE PERIODICITY OF 17385 March 2. Mark. Beckmann. wt “ 13. Baraterio. age « 15. Baraterio. a «22. Wittemberg. Kraus. rE « 24. Wittemberg. Kraus. ass «24. London. Bevis.? ue Me « 24. Mark. Beckmann. ce April 22. Potsdam. Frobes. ae Se « 23. Mark. Beckmann. aya Sept. 25. Reuss. 9 eo OO OD BPP S ON THE PERIODICITY OF THE AURORA BOREALIS. 271 Hartwell, Engl. Glaisher. Moose Factory. Lefroy. Lake Athabasca, Peel’s River. Lefroy. * * * F * bbw bb AN QD oe . Fort Chipewyan. Lefroy. . Fort Chipewyan. Lefroy. . Peel’s River, Moose Factory. Lefroy. . Michipicoton, Toronto. Lefroy. . Alleghany Co.,Lima,Penn. Smith.Records. . Moose Factory. Lefroy. . Fort Chipewyan, Yoncou. Lefroy. . Moose Factory, Lewis and Pelly. Lefroy. . Michipicoton. Lefroy. i . Yoncou, Moose Factory. Lefroy. . Michipicoton, Montreal. Lefroy. . ort Confidence. Lefroy . Fort Chipewyan, Quebec. Lefroy, . Burlington, Vt. Smith. Records. . Leeds, Engl. Glaisher. . Fort Chipewyan. Lefroy. . Alleghany Co., Penn. Lefroy. . Fort Confidence. Lefroy. . Fort Chipewyan, Moose Factory. Lefroy. . Kort Chipewyan, Moose Factory. Lefroy. . Alleghany Co., Penn. Smith. Records. . Hort Confidence, Moose Factory. Lefroy. . Michipicoton. Lefroy. . Yoneou. Lefroy. . Fort Chipewyan, Lefroy. . Moose Factory. Lefroy. . Fort Chipewyan, Moose Factory. Lefroy. . Michipicoton. Lefroy. . Yoncou, Moose Factory, Quebec. Lefroy. . Fort Chipewyan. Lefroy. . Nottingham, Engl. Glaisher. . Fort Chipewyan. Lefroy, . Fort Chipewyan. Lefroy. . Moose Factory, Michipicoton. Lefroy. . Moose Factory. Lefroy. . Hawarden, Grantham, Engl. Glaisher. 2. Fort Chipewyan. Lefroy. . Moose Factory, Michipicoton. Lefroy. . Quebec, Halifax. Lefroy. . Fort Chipewyan, Moose Factory. Lefroy. . Michipicoton. Lefroy. . Albion Mines, Halifax. Lefroy. . Yoncou. Lefroy. . Lima, Penn. Smith. Records. . Moose Factory, Halifax. Lefroy. . Halifax. Lefroy. . Fort Chipewyan, Moose Factory. Lefroy. . Halifax, Albion Mines. Lefroy. April 27. Dubuque, Iowa. Smith. Records. “ 98. Fort Chipewyan. Lefroy. «“ 28. Yoncou, Moose Factory. Lefroy. “ 928. Michipicoton, Halifax. Lefroy. « 29. Fort Chipewyan. Lefroy. “ 29. Moose Factory, Halifax. Lefroy. * « 30. Fort Chipewyan, Moose Factory. Lefroy. *May 1. Moose Factory, Quebec. Lefroy. *« 1. Michipicoton, St. Johns. Lefroy. * « 1. Hartford, Conn., Lima, Penn. Smith. Ree. *« 1, Balt. and Ohio Railroad, Md. Smith: Rec. FB 1. Battle Creek,Mich., Beloit, Wisc. Smith.Rec. * « 2. Moose Factory. Lefroy. “3. Moose Factory, St. Johns. Lefroy. «“ 3. Michipicoton. Lefroy. * « 4. Hartford, Conn. Smith. Records. « 5. Moose Factory. Lefroy. « 5. Hartford, Conn. Smith. Records. “ 6. Moose Factory. Lefroy. 5 “ 7. Moose Factory, Michipicoton. Lefroy. “ 7. Kingston, Toronto. Lefroy. “ 10. Moose Factory. Lefroy. « 11. St. Johns. Lefroy. *« 12. St. Johns. Lefroy. “ 14. Moose Factory. Lefroy. 3 “ 15. Whitehaven, Engl. Lefroy. * « 16. St. Johns. Lefroy. “ 17. Moose Factory, St. Johns. Lefroy. “ 17. Hartford, Conn. Smith. Records. “ 18. Moose Factory, Michipicoton. Lefroy. “ 19. Moose Factory. Lefroy. * « 20. Moose Factory. Lefroy. “ 21. Somerville, N. Y., Keene, Ohio. Smith. Rec. E “ 23. Moose Factory. Lefroy. * « 24, Moose Factory? Lefroy. * « 26. Moose Factory. Lefroy. * « 26. Mouth of St. Lawrence. Lefroy. “ 28. Moose Factory. Lefroy. * « 30. Moose Factory, Michipicoton. Lefroy. “ 31. Moose Factory. Lefroy. June 1. Moose Factory? Lefroy. « 3. Dalhousie,C. B. Lefroy. « 4, London, C. W. Lefroy. * « 5. Moose Factory, Quebec. Lefroy. * « 5. Michipicoton, Dalhousie. Lefroy. ace 5. Montreal, Toronto. Lefroy. *« 5, StJohns, Mouth of St. Lawrence. Lefroy. * « 5. Londonderry, N. H. Smith. Rec. _. ON THE PERIODICITY OF THE AURORA BOREALIS. *June 5. * “ Middlebury, Vt., Ogdensburg, N. Y. Smith. R. . Springfield, Mass., New Haven, Conn. 8. R. . At Sea, Ship Yorktown, Lat. 39° 53’ N. . Smithsonian Records. . Moose Factory, Toronto. . Moose Factory. Lefroy. . Moose Factory. Lefroy. . Moose Factory. Lefroy. . Nottingham, Engl. . Moose Factory. Lefroy. . Dalhousie, London. . Ogdensburg, N. Y. Smith. Records. . Nottingham, Engl. . Moose Factory. Lefroy. . Moose Factory. Lefroy. . Freeport, Penn. . Moose Factory. Lefroy. [ Long. 59° IV. Lefroy. Glaisher. Lefroy. Glaisher. Lefroy. “24. Ceres, Penn. Lefroy. “ 26. Michipicoton, Toronto. Lefroy. “ 26. Mouth of St. Lawrence. Lefroy. “ 27. Moose Factory, Montreal. Lefroy. «“ 2%. Concord, N. H. Smith. Records. “ 27. Ceres, Penn. Smith. Records. “ 30. Moose Factory. Lefroy. *July 2. Moose Factory, Quebec. Lefroy. “3. Moose Factory, London. Lefroy. M & K * . Albion Mines, St. Johns. Lefroy. . New Harmony, Indiana. . Michipicoton. . Moose Factory. Lefroy. Smith, Records. Lefroy. 12. Moose Factory. Lefroy. 13. Moose Factory. Lefroy. 14. Quebec? Toronto? Lefroy. 15. Moose Factory. Lefroy. 17. Albion Mines, Toronto. Lefroy. 17. Michipicoton, Kingston. Lefroy. 17. Londonderry, N. H. Lefroy. 17. Bloomfield, N. J. Lefroy. 18. Moose Factory, Toronto. Lefroy. . Michipicoton. . Kingston, Toronto. . Old Town, Maine. . Moose Factory. Lefroy. . Moose Factory, Michipicoton. Lefroy. . Moose Factory. Lefroy. . Quebec, Montreal. Lefroy. . Moose Factory. Lefroy. . Moose Factory, Michipicoton. Lefroy. Lefroy. Lefroy. Lefroy. x * eK * * K kK eK KH Ke HH % x * Ke eK eK K HK HK KH “ August 1. ON THE PERIODICITY OF THE AURORA BOREALIS. 273 28. Moose Factory. Lefroy. |*August 31. Moose Factory. Lefroy. 28. New York. Smith. Records. * « 31. Toronto, St. Johns. Lefroy. 29. Moose Factory. Lefroy. * © 31, At Sea, Ship Wisconsin, Lat. 48° 59’. 30. Moose Factory. Lefroy. * 31. Smithsonian Records. [Lg. 40° 8’ WW. 31. Moose Factory. Lefroy. *Sept. . Moose Factory? Lefroy. 31. New York. Lefroy. G . Moose Factory, Matawagomingen. Lefroy. Moose Factory. Letroy. Fae . Lewis and Pelly, Dalhousie. Lefroy. 2. Moose Factory. Lefroy. >) Be . Montreal, Albion Mines. Lefroy. 3. Moose Factory, St. Johns. Lefroy. iad oe . Whitehead, Maine. Smith. Records. 4. Moose Factory? Lefroy. Eye 1 . Ogdensburg, Rochester, N.Y. Smith. Ree. 5. Moose Factory, Toronto. Lefroy. pe ORE . Madrid, Seneca Falls, N.Y. Smith. Rec. 1. Moose Factory, Montreal? Lefroy. zp oll . Madison C.H., Va.,Augusta, Ill. Smith. R. 13. Stone, Engl. Glaisher. ze . Milwaukie, Wisc., Detroit, Mich. Smith. R. 14. Stone, Engl. Glaisher. aby At Sea, Ship Wisconsin, Lat. 45° 35’. 17. Matawagomingen. Lefroy. 2 oss . Smithsonian Records. [ Lg. 43° 25. 18. Moose Factory. Lefroy. ©: es . Near Peel’s River, Moose Factory. Lefroy. 20. Moose Factory, Toronto. Lefroy. heed St. Johns. Lefroy. Steuben, Me. Smith. R. 20. Matawagomingen. Letroy. paar . New York, Baldwinsville, N.Y. Smith.R. 21. Moose Factory. Lefroy. sree Kew, Engl. Glaisher. [Rec. 21. Abreast of Sambro Light, N.S. Lefroy. : . Dalhousie. Lefroy. Dublin, N.H. Smith. 21. Nottingham, Engl. Glaisher. £ Moose Factory, Quebec. Lefroy. 23. Albion Mines. Lefroy. < . Montreal, Albion Mines. Lefroy. . Fort Simpson, Toronto. . Moose Factory, London. . Battle Creek, Mich. Lefroy. Lefroy. Smith. Records, * * * kK KK KK * 24. Hawarden, North Shields. Glaisher. 25. Moose Factory? Lefroy. 25. At Sea, Lat. 49° 44° N? Long. 41° 6’ W. 26. Moose Factory, Kingston. Lefroy. 26. Malawagomingen. Lefroy. 26. Toronto, London. Lefroy. 27. Moose Factory. Lefroy. 28. Down the Mackenzie River. Lefroy. 29. Lewis and Pelly, Montreal. Lefroy. 29. Kingston, Toronto. Lefroy. 29. Albion Mines, St. Johns. Lefroy. 29. Sugar Grove, Penn. Lefroy. 29. Battle Creek, Mich., Emerald Grove, Wise. 29. At Sea, Lat. 51° 25! N? Long. 10° 30°W, 30. Moose Factory. Lefroy. 30. Albion Mines, Toronto. Lefroy. [Ree. 30. Londonderry, N.H., Madrid, N.Y. Smith. VOL. 30. Battle Creek, Mich., Emerald Grove, Wisc. . At Sea, Ship Wisconsin, Lt. 48°. Lg. 37°. . At Sea, Ship Roscius, Lt. 48° 59’. Lg. 35°. . At Sea, Ship J. BE. Donnell, Lat. 39° 52’. . Smithsonian Institution. 30. * * * * [Lg. 69° 8 W. Stonyhurst, Whitehaven, Engl. Glaisher. x Bia) es Re DPSDMD DH © OH Aad a TAA AANA DMARD HAMAMAM or PP EF OO Ww & HD oo OD Oo Oo OF DD = = Be He . Kingston, Toronto, London. . Oldtown, Me., Burlington, Vt. Smith. Ree. . Concord, Dublin, White Mis..N.H? S.R. . Attleboro, Mass., Detroit, Mich. Smith. R. . Augusta, Hancock, Ill., Richmond, Ind, S.B. . Durham, Whitehaven, Engl. . Moose Factory, Quebec, Dalhousie. Lefroy. . Montreal, Albion Mines, St.Johns. Lefroy. . Kingston, Toronto, London. . Dublin, N. H. Burlington, Vt. . North Aitleboro, Mass., Augusta, Ill. S.R. . At Sea, ShipT.E.Donnell, Lt.37°. Lg.60°. . At Sea, Ship Henry Clay, Lat. 40° 43°. -~=mithsonian Records. . Whitehaven, Engl. . Moose Factory. Lefroy. . Quebec, Dalhousie. . Madrid, N. Y., Detroit, Mich. Smith. R. . At Sea, Ship Wisconsin, Lat. 44° 59. . Lewis and Pelly. Lefroy. [Lg. 53° 28. . Between Peel and Rat? Rivers. Le . Moose Factory, Albany, H. B. T. Lefroy. . Lewis and Pelly? . Albany, H. B. T., Moose Factory. Lefroy. . Hartwell Rectory, Whitehaven. Glaisher. Lefroy. Glaisher. Lefroy. , Lefroy. [Lg. 59° 56/. Glaisher. Lefroy. Lefroy. Lefroy. 1 Boston Evening Transcript. =Tt eS # io 2] 7} uo] ot SEO I OK ee RR HK KK KR KK He KK KK RK KK KH OK KR OK OK OR OK n a “ . 15. 15. 15. 15. 15. 16. 16. 16. 16. 17. 18. 20. 20. 21. 22. 22. 23. 23. 24. 26. 27. 21. 27. 28. 28. 28. 28. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. 29. ON THE PERIODICITY OF THE AURORA BOREALIS. Lewis and Pelly, Moose Factory. Lefroy. Quebec, Kingston, Toronto. Lefroy. Stone, Hartwell Rectory, Nottingham, Gainsborough, Stonyhurst, Whitehaven, Harpham, Yorkshire, Durham. Glaisher. Lewis and Pelly, Albany, H. B. T. Lefroy. Moose Factory, Montreal. Lefroy. Kingston, Toronto, St. Johns. Lefroy. North Attleboro, Mass. Smith. Records. Albany, H. B. T., Moose Factory. Lefroy. Montreal. Lefroy. Lewis and Pelly, Albany, H. B. T. Lefroy. Moose Factory, Kingston. Lefroy. Moose'Factory. Lefroy. Lewis and Pelly, Albany, H. B. T. Lefroy. Moose Factory, Dalhousie. Lefroy. Albany ? H.B.T. Moose Factory? Lefroy. Ogdensburg? N.Y. Smith: Records. Lewis and Pelly. Lefroy. Pelly River. Lefroy. Pelly River, Moose Factory. Lefroy. Matawagomingen, St. Johns. Lefroy. Hawarden, Durham, Engl. Lefroy. Pelly River, Quebec. Lefroy. Matawagomingen. Lefroy. Washington, D.C. Fairbanks. [sher. Norwich, Harpham, Durham, Engl. Glai- Pelly River, Albany, H. B. T. Lefroy. Quebec, Toronto, St. Johns. Lefroy. Dublin, N. H., Burlington, Vt. Smith. Rec. Middletown, Conn., Rochester, N. Y. S. R. Madrid, Ogdensburg, N. Y. Smith. Rec. Bloomfield, Burlington, N. J. Smith. Rec. Morrisville, Morristown, Lima, Pa. 8. BR. Sugar Grove, Gettysburg, Pa. Smith. Ree. Sykesville, Frederick, Md. Smith. Ree. Washington, D. C. Smith. Records. Madison, Winchester, Diamond Grove, Va., Chapel Hill, N.C. Charleston,S. C. Smith.R. Hillsboro, Republic, Ohio. Smith. Records. | Bowling Green, Ky. Clarkesville, Te., LakeScuppernang,Lebanon, Te. Smith. R. | Howell, Battle Creek, Mich. Smith. Rec. Keucosha, Milwaukie, Wisc. Plattesville, Beloit, Wisc. Smith. Rec. | Smith. Records. | Dubuque, Muscatine, Iowa. Smith. Records. | Petersburg, Augusta, Ill. Smith. Records. Erie, Eutau, Alabama, Richmond, Ind., * * *¥ KK KK KK OK HK OK K *Sept. 29. “ * * eK K Ke HK KK KH KH * * © ic} + ree | oe % ow ow SORMRARTF FER wWOWNNNNHHHNHDHESS a a on oe b aealll eve ore YY ce 15 “ 17 ol aT ¢ a [ooo = alo a] 18. “4 po) “20. * * K KK HK K HK a n NS —) bo i) 29. 29. 29. 29. . Hartwell House, Nottingham. Glaisher. . Maidenstone Hill, Stone. . Hartwell Rectory, Cardington. . Albany, Dalhousie, Toronto. . Moose Factory. Lefroy. SagHarbor, N.Y., . At Sea, Ship Sturgis, Lat. 29°. Lg. 73°. . Nittingham, Yorkshire? Engl. . Lewis and Pelly, Toronto. Lefroy. . North Shields, Dunino. . Cardington, Nottingham. . Albany, H. B. T. Letroy. . Nottingham, Durham. . Albany, H. B. T., Moose Factory. Lefroy. . Albany, H. B. T. Lefroy. . Fort Simpson, Moose Factory. Lefroy. . Fort Simpson? Lewis and Pelly. Lefroy. . Fort Simpson. . Fort Simpson. . Fort Simpson. . Fort Simpson. . Stonyhurst, Engl. 5. Fort Simpson, Moose Factory. Lefroy. . Slonyhurst, Engl. . Lewis and Pelly? Albany, H.B.T. Lefroy. . Moose Factory, Quebec. 8. Fort Simpson, Dalhousie. . Old Town, Maine, Burlington, Vt. Smith. . Toronto, Bond Lake. At Sea, Ship H. Clay, Lt. 46°. Lg. 42°. At Sea, ShipAlarm, Lt. 29°43’. Lg. 64° 16/. At Sea, Ship J. EB. Donnel, Lat. 38° 24’. Smithsonian Records. [ Lg. 32° 30. Wakefield, Durham, North Shields, Glaisher. Glaisher. Lefroy. Glaisher. Dalhousie, Albion Mines. Lefroy. Toronto, St. Johns. Lefroy. Dublin, N.H., Dubuque, Iowa. Smith. Ree. Maidenstone Hill, Oxford, Cardington, Norwich, Nottingham, Stonyhurst, Whitehaven, Durham. Glaisher. Glaisher. Yorkshire, Engl. Glaisher. Moose Factory, Toronto? Lefroy. Glaisher. Lefroy. Glaisher. Moose Factory, Toronto. Lefroy. Lefroy. Lefroy. Lefroy. Glaisher. Glaisher. Lefroy. Lefroy. [Ree. Lefroy. . St. Juhns, Lake Champlain. Lefroy. Durham, Engl. Glaisher. [Smith. Rec. . Fort Simpson. Lefroy. Bucksport, Me. . Fort Simpson, Albany, H. B. T. Lefroy. . Dalhousie, Montreal. . Albion Mines, St. Johns. Lefroy. Lefroy. * HX KK HH KKH Hw KH OH OK mH OH OM bo bo . Quedec, Kingston, London. . Steuben, Me., Manchester, N.H. Smith. Rec. . Dublin, L ndonderry, N. H. Smith. Rec. . Burlington, Middlebury, Vt. Smith. Ree. . Somerville, Ogdensburg, N. Y. Smith. Rec. . Middletown, Conn., Burlington, N. J. 8. R. . Washington, D. C., Milwaukie, Wisc. 8. R. . Albany, H. B. T., Toronto. . Moose Factory. Lefroy. 2.. Lewis and Pelly, Moose Factory. Lefroy. - Montreal, Kingston. Lefroy. . Toronto, St. Johns. . Fort Simpson, Quebec. 23. Albany, H. B. T., Dalhousie. . Burlington, Vt..Manchester,N.H.Smith.Ree. . Londonderry, N. H. Smith. Rec. . Fort Simpson, Moose Factory, Quebec. Lefroy. . Fort Simpson, Albany, H. B.T. Uefroy. | . Fort Simpson, Lewis and Pelly. Lefroy. | 26. Moose Factory, Toronto. 26. Albany, H. B. T. Lefroy. . Moose Factory. Lefroy. . Moose Factory, Quebec. . Albion Mines, St. Johns. . Dalhousie. Lefroy. At Sea. Smith. Rec. . Wakefield, Stonyhurst. Durham. Glaisher. . Whitehaven, North Shields. . St.Johns. Lefroy. Hartwell Rectory. Glaisher. . Nottingham, Wakefield, Dunino. . Lewis and Pelly ? . Stonyhurst? Glaisher. . Lewis and Pelly? Lefroy. . Albany, H. B. T., Moose Factory. Lefroy. . Albany, H.B.T. Lefroy. . Peel’s River, Albany, H.B.T. Lefroy. | . Toronto? Lefroy. . Fort Simpson, Peel’s River. . Stonyhurst, Engl. . Pelly River, Fort Simpson. . Peel’s River, St. Johns. Lefroy. . Fort Simpson, Peel’s River. Lefroy. . Toronto, St. Johns. Lefroy. ON THE PERIODICITY OF Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Glaisher. Glaisher. Lefroy. Fort Simpson, Toronto? Lefroy. Aylesbury, Nottingham. Glaisher. Peel’s River. Lefroy. Stonyhurst. Glaisher. Lewis and Pelly. Lefroy. Lewis and Pelly. Lefroy. Lefroy. Glaisher. Lefroy. THE AURORA BOREALIS. 275 *Noy. 15. At Sea, Ship Roscius, Lt. 51° 57'N. Lg. 26° * * * * h 15. Smithsonian Records, 16 28. Peel’s River. SOPH DAD AAAS Op oo bo ee pt pe = i ~) Is [35 W. . Fort Simpson. Moose Factory. Lefroy. . Lewis and Pelly? Lefroy. [10° Ww. . At Sea, Ship Roscius, Lt. 50°37’ N. Lg. 25° - Moose Factory? Toronto. Lefroy. . At Sea,Ship Roscius, Lt. 50°. Lg. 22°54 W. . Toronto. Lefroy. . Peel's River, Moose Factory. Lefroy. . Fort Simpson? Lefroy. . Aylesbury, Engl. Glaisher. . Fort Simpson,’ Lewis and Pelly.t Lefroy. . Aylesbury, Engl. Glaisher. . Pelly River, Fort Simpson. Lefroy. . Fort Simpson, Peel’s River. Lefroy. . Toronto. Lefroy. 4. Peel's River, Moose Factory. Lefroy. . Toronto. Lefroy. . Dunino, Engl. Glaisher. . Fort Simpson, Peel’s River. . Fort Simpson. Lefroy. . Stonyhurst, Engl. Glaisher. . Fort Simpson. Lefroy. Lefroy. . Peel's River, Lewis and Pelly. Lefroy. . Albany, H. B. T. Lefroy. Lefroy. . Moose Factory,.Toronto. Lefroy. . Peel’s River, Toronto. Lefroy. . Fort Simpson, Peel’s River. Lefroy. . Lewis and Pelly. Lefroy. . Albany, H. B.T., Toronto. Lefroy. Peel's River. Lefroy. Peel’s River. Lefroy. Fort Simpson, Torento? Lefroy. Fort Simpson. Lefroy. Toronto. Lefroy. [2". At Sea, Ship Yorktown, Lt. 50°13’. Lg. 33° . Smithsonian Records. Hawarden, Liverpool, North Shields, . Wakefield, Durham. Glaisher. Peel’s River, Lewis and Pelly? Lefroy. St. Johns. Lefroy. . Hawarden, Engl. Glaisher. . Peel’s River. Lefroy. . Fort Simpson, Peel’s River. Lefroy. . Albany, H. B. T., Moose Factory. Lefroy. . Pelly River, Lewis and Pelly. Lefroy, 1 Aurora Australis. ~~ 276 x * e * * * * kK * KH HK KH HK * * Dec. 12. Albany, H. B. T., Toronto. 13. Lewis and Pelly, Albany, H. B. T. Lefroy. 13. Moose Factory, Toronto. Lefroy. 14, Pelly River, Fort Simpson. Lefroy. 14. Albany, H. B. T. Letroy. 14. Peel’s River, Moose Factory. Lefroy. 15. Pelly River, Fort Simpson. Lefroy. 15. Peel’s River. Lefroy. 16. Pelly River, Fort Simpson. Lefroy. 16. Peel’s River. Lefroy. 17. Pelly River, Fort Simpson. Lefroy. oer lo os | 18. ft ja nH oe SSooe bh bo bo NOHNWNHNNNFRrP er SOS Npwpwnwhdy pw phd Ww Wp Bs . Peel’s River, Lewis and Pelly. Lefroy. . Peel’s River, Albany, H. B. T. Lefroy. . AtSea,ShipRoscius, Lt. . Smithsonian Records. . Pelly River, Fort Simpson. . Peel’s River, Lewis and Pelly. Lefroy. . Pelly River, Fort Simpson. . Lewis and Pelly, Albany, H. B. T. Wefroy. . Peel’s River, Moose Factory. Lefroy. . At Sea, Ship Roscius, Lt. 56° 56°N. Lg.18°. | . Pelly River, Fort Simpson. Lefroy. [40 W. . Lewis and Pelly, Albany, H, B. T. Lefroy. - Quebec, Montreal, Toronto.St. Johns. Lefroy. | . Albany, H. B. T., Peel’s River. Lefroy. . Moose Factory, Dalhousie, St.Johns. Lefroy. . At Sea, Ship New World, Lt. 50° 48'. Lg. | . Stonyhurst, Whitehaven. . Nottingham, Hawarden. . Durham, North Shields, Dunino. Glaisher. . Pelly River, Fort Simpson. . Albany, H.B.T., Lewis and Pelly? Lefroy. . Peel’s River, Moose Factory. Lefroy. . Dalhousie, Toronto, London. Lefr,*[284° W. . At Sea, Ship New World, [t. 51° 28'. Lg. . At Sea, Ship Roscius, Lt. 55° 37'N. Lg.23°. . Smithsonian Records. . Whitehaven, Dunino. . Pelly River, Fort Simpson. . Lewis and Pelly, Albany, H. B. T, Lefroy. | . Peel’s River, Moose Factory. Lefroy. . Pelly River, Fort Simpson? Lefroy. . Dalhousie, Lewis and Pelly. Lefroy. . Toronto, London, St. John. ON THE PERIODICITY OF Lefroy. Moose Factory, Toronto. Lefroy. ¢ 55° 56. Lg. 11° 57!. Lefroy. Lefroy. Peel’s River, Moose Factory. Lefroy. [40 W. | Pelly River, Lewis and Pelly. Letroy. Smithsonian Records. [27° 16’ W. Glaisher. Glaisher. Lefroy. LW. Glaisher. Lefroy. Lefroy. THE AURORA BOREALIS. * o is} i to ror) * & * 6 * 6 * «& * 6 * & * & * & * “ * & * * « * * « * * « Jan, “ ¥ 6 “ “ “ce “c “ “ “ “ “ “ “ “ “ce * «& * 6 “ * * « * & * « * « x 6 * « * 6 * « bo bb & t& Re LOoESa tS for) bo vs) 2 Go are . Pelly River, Fort Simpson, Peel's River, . Albany, H.B.T., Moose Factory. Lefroy. . Pelly River, Fort Simpson. Letroy. . Lewis and Pelly. Lefroy. — . Peel’s River, Dalhousie. Lefroy. . Pelly River, Toronto. Lefroy. . Grantham, Dunino. Glaisher. . Fort Simpson, Peel’s River. Lefroy. 4 ~~ 29. Montreal, Kingston. Lefroy. 29. Toronto, St. Johns. Lefroy. [58° 2. 29. At Sea, Ship Plymouth, Lat. 36° 51'S. Lg. 29. Smithsonian Records. 29. North Shields, Dunino. Glaisher. 29. Grantham, Stonyhurst. Glaisher. 30. Fort Simpson, Peel's River. Lefroy. . At Sea, ShipPlymouth, Lt.37°S. Lg. 61° Bo . Smithsonian Records. 1852 . Peel's River. Letroy. . Lewis and Pelly. Lefroy. Fort Simpson. Lefroy. . North Shields, Dunine, Glaisher. . Albany, H. B. T., Moose Factory. Lefroy. . Peel’s River. Lefroy. . Peel’s River, Lewis and Pelly. Lefroy, . Fort Simpson, Peel’s River. Lefroy. . Moose Fuctory. Lefroy. Mayme Wh 13. Albany, H. B. T., Moose Factory. Lefroy. 14. Peel’s River, Albany, H. B. T. Lefroy. 14. Moose Factory. Lefroy. 15. Fort Simpson, Peel’s River. Lefroy. 15. Moose Factory. Lefroy. 16. Fort Simpson, Peel’s River. Lefroy. 16. Moose Factory. Lefroy. 17. Albany, H. B. T., Moose Factory. efroy. 17. Durham, Engl. Glaisher. 18. Moose Factory? St. Johns. Lefroy. 19. Albany, H. B. T., Moose Factory. Lefroy. 19. Quebec, Montreal, Kingston. Lefroy. 19. Toronto, London, Halifax. Lefroy. 20. Fort Simpson ? Lewis and Pelly. Lefroy. 20. Moose Factory? Albany, H. B. T. Wefroy. 20. Halifax, St. Johns. Lefroy. [Lg. 9° W. 20. At Sea, Ship Hendrick Hudson, Lat. 49°N. 20. Smithsonian Records. 20. Falmouth, Engl. Glaisher. 1 Aurora Australis. * = =] ** &* KKH HK * * * * KK K * *Feb * 6 * 6 25. Durham, Dunino, Hawarden. SAAN AMNER NYE ON THE PERIODICITY OF . Peel’s River, Albany, H. B. T. Lefroy. . Moose Factory, Toronto. Lefroy. . Aylesbury, Durham, Engl. Glaisher. 22. Albany, H. B. T., Moose Factory. Lefroy. . Halifax. Lefroy. HartwellRectory.Glaisher. . Peel’sRiver, Albany, MooseFactory. Lefroy. . Hatton, Oxford, Hartwell Rectory, . Cardington, Grantham, Gainsborough, . Hawarden, Durham, Dunino. Glaisher. . Fort Simpson, Peel’s River. Lefroy. 24, Moose Factory, Albany, H. B. T. Lefroy. 24. Kingston, Toronto. Lefroy. . Fort Simpson, Lewis and Pelly. Lefroy. . Moose Factory, Albany, H. B. T. Wefroy. . St. Johns, Halifax. Lefroy. Glaisher. . Manchester, Stonyhurst. Glaisher. . Fort Simpson, Peel’s River. Lefroy. . Moose Factory, Albany, H. B. T. Lefroy. . Montreal, Toronto. Lefroy. 28. Albany, H. B. T., Moose Factory. Lefroy. . Albany, H. B. T., Moose Factory. Lefroy. . Peel’sRiver,Albany,MooseFactory. Lefroy. 30. RoseHill, Thame, NorthShields. Glaisher. 31. Fort Simpson, Albany, H. B. T. Lefroy. 31. Moose Factory, St. Johns. 31. Dunino, Engl. 1.1 Fort Simpson, Lewis and Pelly. Lefroy. Lefroy. Glaisher, Moose Factory, Albany, H. B. T. Lefroy. Kingston, Toronto, St. Johns. Lefroy. . Lewis and Pelly. Lefroy. Fort Simpson, Lewis and Pelly. Lefroy. . Highfield House, Engl. Glaisher. . Lewis and Pelly. Lefroy. . Fort Simpson, Halifax. Lefroy. . Lewis and Pelly? Lefroy. . Albany, H. B. T., Moose Factory. Lefroy. Fort Simpson, Lewis and Pelly. Lefroy. . Fort Simpson. Lefroy. ‘ 11. Fort Simpson, Lewis and Pelly. Lefroy. 12. Fort Simpson. 13. Lewis and Pelly, Albany, H. B. T, Lefroy. 13. Moose Factory, Halifax. 14. Fort Simpson, Quebec, Montreal. Lefroy. 15. Fort Simpson, Lewis and Pelly. Lefroy. 15. Lefroy. Lefroy. Albany, H. B. T., Moose Factory. Lefroy. 1 The aurora was visible at Peel’s River almost every night until the 22d: VOL. X. 35 * THE AURORA BOREALIS. *Feb. KK * KK Ke KK KK KK KF KK KK KH KK KK K HK HK HK *K * eK Kw KK KK KH KK KK K KH K KK KK K . London, Halifax, St. Johns. . At Sea, Ship Hendrick Hudson, Lt. 47° N. . Smithsonian Records. . In England, from Lt. 50°to 57°. Glaisher. . Fort Simpson, Peel’s River. . Lewis and Pelly, Moose Factory. Lefroy. . Albany, Sault St. Marie, Kingston. Lefroy. . Quebec, Toronto, Montreal. . London, Halifax, St. Johns. . At Sea, Ship Hendrick Hudson, Lt. 47° N. . Smithsonian Records. . In England, from Lt. 49° to 57°. Gilaisher. . Fort Simpson, Lewis and Pelly. Lefroy. . Moose Factory, Montreal. . Quebec, Kingston, Toronto. . AtSea, Barque Kepler, Lt. 35° N. Lg. 49° W. . AtSea, Ship Constantine, Lt.51° N. Lg.15° W. . Smithsonian Institution. . Helston, Norwich, Hngl. . Fort Simpson, Quebec. . Lewis and Pelly, St. Johns. . Helston, Grantham, Highfield House, . Gainsborough, Wakefield, Stonyhurst, . Whitehaven, Durham, Glasgow. Glaisher. . Highfield House, Engl. 277 . Kingston, Toronto, Halifax. Lefroy. . At Sea, Ship Siddons, Lt. 46°N. Lg. 46° W. . At Sea, Ship Hendrick Hudson, Lt. 47°N. . Smithsonian Records. ° . In England, from Lt. 51° to 55°. Glaisher. . Fort Simpson, Lewis and Pelly. Lefroy. . Moose Factory, Montreal. . Matawagomingen, Quebec. . Toronto? Kingston? London. . Halifax. Lefroy. Dunino, Engl. Glaisher. . At Sea, Ship Siddons, Lt. 47°.N. Lg. 40° W. . At Sea, Ship Hendrick Hudson, Lt. 47° N. . Smithsonian Records. . Fort Simpson, Lewis and Pelly. Lefroy. . Moose Factory, Matawagomingen. Lefroy. . Albany, Montreal, Kingston. . Quebec, Halifax, St. Johns. Lefroy. . Highfield House, Durham. Glaisher. . North Shields. . Lewis and Pelly, Moose Factory. Vefroy. [Lg. 32° W. Lefroy. Lefroy. Lefroy. [Lg. 36°. Lefroy. Glaisher. . Quebec, Matawagomingen. Lefroy. . Albany, H. B. T., Montreal. Lefroy. . Toronto, Kingston. Lefroy. Lefroy. [ Lg. 43° W. Lefroy. Lefroy. Lefroy. [Lg. 44° W. Lefroy. Lefroy. Glaisher. Lefroy. Lefroy. Glaisher. * * * *x* * kK * “ “ . 20. 23. 23. 24. 25. 25. 26. 26. 27. 27. 27. 27. 28. 28. 28. 29, March 1. : . Moose Factory, Halifax. Lefroy. . Fort Simpson, Moose Factory? Lefroy. . Highfield House, Engl. G)laisher. . Fort Simpson. Lefroy. . Lewis and Pelly, Moose Factory. Lefroy. . Highfield House, Engl. Glaisher. . Lewis and Pelly, Fort Simpson. Lefroy. . Moose Factory. Lefroy. . Albany, H. B. T., Moose Factory, Uefroy. . Peel’s River, Quebec. Lefroy. . Lewis and Pelly, Halifax. Lefroy. . Lewis and Pelly, Fort Simpson. Lefroy. . Fort Simpson, Albany, H. B. T. Lefroy. . Lewis and Pelly, St. Johns. Lefroy. 10. . Moose Factory, Toronto. Lefroy. . Fort Simpson, Kingston. Lefroy. . St. Johns, Halifax? Lefroy. . Moose Factory, Lewis and Pelly.. Lefroy. . Fort Simpson, Moose Factory? Lefroy. . Peel's River, Albany, H. B. T. Lefroy. . Lewis and Pelly, Halifax. Lefroy. . Fort Simpson, London. Letroy. . Lewis and Pelly. Lefroy. . Peel’s River. Lefroy. . Fort Simpson, Moose Factory. Lefroy. . Lewis and Pelly, Peel’s River. Lefroy. . Albany. Lefroy. Portsmouth, N. H2 . Fort Simpson, Moose Factory. Lefroy. . Lewis and Pelly, Halifax. Tefroy. OOWMDNANGAACAT ANH Y ON THE PERIODICITY OF Peel's River, Albany, H. B. T. Lefroy. Toronto, Halifax. Lefroy. Stonyhurst, Durham, Engl. Glaisher. Peel’s River, Ship Karius at Sitka.Lefroy. Ship Karius at Sitka. Lefroy. Highfield House, Engl. Glaisher. Lewis and Pelly? Moose Factory. Wefroy. Highfield House. Glaisher, Peel's River, Lewis and Pelly. efroy. Montreal, Moose Factory. Lefroy. Quebec, Halifax, St. Johns. Lefroy. Durham, North Shields, Dunino. Glaisher. Lewis and Pelly, St. Johns. Lefroy. Ship Karius at Sitka. Wetroy. Aylesbury, Engl. Glaisher. Lewis and Pelly, Moose Factory. Wefroy. Lewis and Pelly. Lefroy. Lewis and Pelly. Lefroy. 1 Portsmouth Journal. xe KK bs THE AURORA BOREALIS. March 17. co 8) ccs: * «19, * « 19, ie 20, * 6 20 * 6 20 * 6 a1 ¥ “ce wih * “ Ail « 99 «122, * 6 25 ¥* “ 26 * 6 26 * “ aft “ 28 * “ 29 “ 30 * * * K K *K K * = i=) R Bee ee NonwRe ary is a SSHDDDOMAANEPWH Ee Essex Coast Lefroy. Fort Simpson, Moose Factory. Lefroy. Albany, H. B. T., Toronto. Lefroy. Moose Factory, Kingston. Lefroy. Albany, H. B. T. Lefroy. Fort Simpson, Moose Factory. Lefroy. . Albany, H. B.T., Toronto. Lefroy. . Halifax. Lefroy. Stonyhurst. Glaisher. . Moose Factory, Albang, H. B. T. Lefroy. . Lewis and Pelly, Toronto. Lefroy. - Hawarden, Engl. Glaisher. . Moose Factory, Albany, H. B. T. Lefroy. . Lewis and Pelly? Halifax. Lefroy. . Stonyhurst, Engl. Glaisher. . Fort Simpson, Lewis and Pelly. Lefroy. . Sault St. Marie, Toronto. Lefroy. . Kingston, London, Halifax. Lefroy. . Fort Simpson, Moose Factory. Lefroy. . Albany, H.B.T. Lefroy. Highfield House. . Fort Simpson, Moose Factory ? Quebec. L. . Moose Factory. Lefroy. . Lewis and Pelly, Toronto. Lefroy. . Kingston, London, Halifax. Lefroy. . Stonyhurst, Engl. Glaisher. . At Sea, Ship Roscius, Lt. 51°N. Lg. 7° W. . Smithsonian Records. . Highfield House, Engl. Glaisher. . Quebec, Toronto? Lefroy. . Lewis and Pelly, Montreal. Lefroy. . Kingston, Halifax. Lefroy. . Halifax. Lefroy. . Fort Simpson, Halifax. Lefroy. . Lewis and Pelly? Lefroy. Kingston, London. Lefroy. . Fort Simpson, Toronto. Lefroy. . Matawagomingen, London. Lefroy. . Kingston, St. Johns. Lefroy. . Stonyhurst, Engl. Glaisher. . Fort Simpson, Lewis and Pelly. Lefroy. . Matawagomingen, Quebec. Lefroy. - Toronto, Kingston, London. Lefroy. . Lewis and Pelly. Lefroy. . Stonyhurst, Engl. Lefroy. . Lewis and Pelly. Lefroy. . Sault St. Marie, Toronto. Lefroy. . Lewis and Pelly, Toronto. Lefroy. fy Ga: Glasgow. Lefroy. 1 Between Blackwater and Crouch Rivers. * * KK KK K K * * we kK * * * * KK K KK K * = oOo . Matawagomingen. . London, Toronto. . At Sea, Ship Garrick, Lt.47°N. Lg. 29° W. . Smithsonian Records. . Toronto. . Fort Simpson, Lewis and Pelly. Lefroy. . SaultSt.Marie.Lefroy.Stonyhurst. Glaisher. . Kingston? Toronto? St. Johns. . Rose Hill, Engl. . Oxford, Highfield House. . Fort Simpson 2? Lewis and Pelly. Lefroy. . Toronto, London, Halifax. . Highfield House, Engl. . Lewis and Pelly, London. . Matawagomingen. . Mighfield House, Engl. . Lewis and Pelly. Lefroy. . Highfield House, Engl. . St. Johns. . Fort Simpson. . Stone, Engl. . Stone, Hartwell Rectory, Engl. . Hartwell Rectory, Highfield House. Glai- . Matawagomingen. POMRAATMTaAwHnNREHES ‘ON THE PERIODICITY OF THE AURORA BOREALIS. Lefroy. Lefroy. Lefroy. Dunino. Glaisher. Lefroy. Glaisher. Glaisher. Lefroy. Glaisher. Lefroy. Lefroy. Glaisher. Glaisher. Lefroy. Lefroy. Glaisher. Glaisher. Lefroy. Lefroy. [sher. Toronto ? St. Johns. St. Johns. Lefroy. . Toronto? Lefroy. . Montreal, Kingston, Toronto. . Matawagomingen. . Kingston, Toronto. . Kingston, Toronto. Lefroy. 10. . Toronto. . Quebec. . Toronto. . Quebec, Montreal. . Kingston, Toronto ? Halifax. . Quebec, Matawagomingen. . Toronto, Halifax. . Montreal, Toronto. . Toronto, Halifax. . AtSea, Ship Yorktown, Lt. 40°N. Lg.12° W. . Montreal, Toronto, St. Johns. . Quebec, Sault St. Marie. . St. Johns, Toronto. Lefroy. . Kingston. . Grosse Isle (below Quebec). Lefroy. . Quebec, Montreal, Toronto. ‘ Lefroy. Lefroy. Lefroy. London, Halifax. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. * * K * * * * KK KK KK KK KK KK KK KH K KK * June eel ell el ce ce ped PHN PER Sa om ow . Kingston, Toronto. . Quebec, Toronto. . Kingston, Toronto. . Stone, Engl. . Kingston. . Highfield House, Engl. . Halifax ? . Penetanguishene, Halifax. Lefroy. . Penetanguishene. . Great Britain. . Halifax. - Quebec, Grosse Isle. . Kingslon, Toronto. . Penetanguishene, Quebec. . Grosse isle, Kingston. . Toronto, Montreal. . Halifax. Lefroy. Great Britain. Glaisher. . Quebec, Grosse Isle. . Kingston, Toronto, Montreal. . Toronto? Lefroy. . Penetanguishene, Quebec. . Toronto, Sault St. Marie, Halifax. Lefroy. . Quebec, Grosse Isle. . Penetanguishene, Kingston. . Toronto, Montreal, Halifax. Lefroy. . Grosse Isle, Kingston. . Toronto, Montreal. Lefroy. . Toronto, Montreal. . Great Britain. . Penetanguishene. . Great Britain. . Quebec, Grosse Isle. Lefroy. 279 Toronto. Lefroy. Grosse Isle, Quebec. Lefroy. Montreal, Kingston, Toronto. Lefroy. Smithsonian Records. [Long. 79°. At Sea, Ship White Squall, Lat. 53° N? Toronto. Lefroy. Grosse Isle, Quebec, Montreal. Lefroy. . Kingston, Toronto, Halifax. Lefroy. . New Haven. Smith. Rec. Greenwich. Gl. . Grosse Isle, Quebec. Lefroy. . Montreal, Halifax. Lefroy. . At Sea, Ship Garrick, Lt. 40°N. Lg. 69° W. . Smithsonian Records. Quebec, Kingston, Toronto. Lefroy. Lefroy. Lefroy. Lefroy. Glaisher. Lefroy. Toronto. Lefroy. Glaisher. Lefroy. Lefroy. Glaisher. Lefroy. Penetanguishene, Halifax. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Glaisher. Lefroy. Glaisher. 280 July 15. Toronto, Montreal. 19. “ “ce > iS 99 * * * * * 23. 24. bo a we bo to SosoaN ©9 pe . Penetanguishene. . Halifax, Kingston. . Portage la loche. 9. Penelanguishene. . Clear Water River. . Toronto. . Athabasca River. ON THE PERIODICITY OF Lefroy. Penetanguishene. Lefroy. Kingston, Toronto, Halifax. Montreal, Halifax. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. 3. Halifax? Lefroy. CSCHOMDDADATARAAKNS Beh - Oo BR eee Pe © Or or or & ee bo b bw pp tb Hm H OO OO bo a) = 25. . Fort Simpson. . Fort Simpson, Slave River. . Portage Brule. . Salt River, drifting below. Lefroy. . Penetanguishene, Grosse Isle. . Quebec, Montreal, Toronto. . Salt River, drifting below. Lefroy. . Fort Resolution, Halifax. Lefroy. . At Sea, Ship Plymouth Rock, Lat. 47° N. . Smithsonian Records. . Slave Lake, Quebec. . Big Island, Grosse Island, Quebec. Lefroy. . Penetanguishene, Toronto. . Near Fort Simpson, Montreal. . Penetanguishene, Toronto. . Grosse Isle, Quebec. . Quebec. . Quebec. . At Sea, Ship Yorktown, Lt. 42°N. Lg.51° W. . Smithsonian Record. . Quebec. . Lewis and Pelly. Lefroy. . Lewis and Pelly. Lefroy. . Toronto, Halifax. Lefroy. . Lewis and Pelly. Lefroy. . At Sea, Ship Ashburton, Lt. 40° N. Lg. 65° W. . At Sea. Ship Plymouth Rock, Lat. 44° N. . Smithsonian Records. . Penetanguishene. . Toronto. . At Sea, Ship Plymouth Rock, Lat. 43° N. . Smithsonian Records. . Fort Simpson, Toronto: . Pelly River, 120 ms. below Ft. Selkirk. Lef. . Grosse Isle, Toronto. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. [Lg. 535° W. Lewis and Pelly, Toronto. Lefroy. Lefroy. Lefroy. [Lg. 58° W. Lefroy. Lefroy. [Lg. 21° W. THE AURORA BOREALIS, Sept. * « * 6 * 6 * & * * 6 “ “ “ * 6 * 6 * “ * 6 * 6 * 6 * “ * “ * 6 “ * “ * « * “ * “ * “ * & * 6 * “ * « * 6 * 6 * 6 * 66 * «& * 6 * “ * « * 6 * 6 * “ “ “ * & * 66 . Pelly River, Fort Simpson. . Penetanguishene. . Pelly River, Fort Simpson. . Pelly River, Peel’s River. . Fort Simpson, Fort George. . Grosse Isle, Quebec. . Peel's River, Fort Simpson. . Fort George, Toronto. . Peel’s River, Fort Simpson. . FortGeorge. Lefroy. Gt. Britain. Glaisher. . Fort Simpson, Toronto. . Quebec. . Pelly River. . Pelly River, Peel’s River, Toronto. Lefroy. . Montreal, Penetanguishene. . Peel’s River, Penetanguishene. . Toronto, Quebec. . Montreal. Lefroy. Gt. Britain. Glaisher. . Peel’s River, Fort Simpson. . Grosse Isle, Quebec. . Montreal. Lefroy. Great Britain. Glaisher ? . Peel's River, Fort Simpson. Lefroy. 9. Penetanguishene, Toronto. . Kingston. Lefroy. Gt. Britain. Glaisher ? . Pelly River, Peel’s River. . Fort Simpson, (Quebec. . Halifax. Lefroy. Great Britain. Glaisher ? . Pelly River, Peel’s River. . Fort Simpson, Fort George. . Toronto, Kingston. . Halifax. . Pelly River, Fort George. . Toronto, Halifax. . Fort Simpson. . Quebec. . Peel’s River, Grosse Isle. Lefroy. . Toronto, Quebec, Halifax. . Fort Simpson, Peel’s River. . Pelly River. . Fort Simpson, Quebec, Toronto. . Fort Simpson. Lefroy. Penetanguishene,. Lefroy. . Fort Simpson, Grosse Isle, Quebec. Lefroy. . Penetanguishene, Toronto. Lefroy. Pelly River, Fort Simpson. Lefroy. Fort George, Penetanguishene. Lefroy. Pelly River, Peel’s River, Toronto. Lefroy. Fort George, Penetanguishene. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Gt. Britain. Glaisher ? Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. * * K * * * * K * * * * * * *¥ KK K K * ON THE PERIODICITY OF THE AURORA BOREALIS. Oct. 4. Kingston. Lefroy. «5. Peel’s River, Toronto, Kingston. Lefroy. «5. Halifax. Lefroy. Stone, Engl. Glaisher. “ 6. Toronto, Penetanguishene. Lefroy. «7. Quebec. Lefroy. “ 8. Fort Simpson. Lefroy. “ 11. Pelly River, Penetanguishene. Lefroy. “ 12. Fort Simpson, Peel’s River. Lefroy. “ 12. Quebec, Toronto. Lefroy. « 12. Montreal, Kingston. Lefroy. « 13. Peel’s River. Lefroy. “ 16. Peel’s River, Toronto, Lefroy. « 17. Fort Simpson, Peel’s River, Quebec. Lefroy. « 18. Fort Simpson. Lefroy. “ 19. Fort Simpson, Peel's River. Lefroy. 19. Toronto, Kingston. Lefroy. « 19. Penetanguishene, Montreal. Lefroy. « 20. Peel’s River, Quebec. Lefroy. « 20. Toronto, Montreal. Lefroy. “ 21. Peel’s River. Lefroy. « 23. Fort Simpson, Peel’s River. Lefroy. “ 23. Fort George. Lefroy, Stone, Engl. Glaisher. «“ 924. Peel’s River. Lefroy. Stone, Engl. Glaisher. “ 25. Fort Simpson, Peel’s River. Lefroy. “ 25. Stone, Engl. Glaisher. « 26. Fort Simpson. Lefroy. Stone, Engl. Glaisher. « 27. Fort George. Lefroy. « 29. Fort Simpson. Lefroy. “ 31. Fort Simpson, Peel's River. Lefroy. Nov. 1. Peel’s River. Lefroy. «2. Fort Simpson, Lefroy. [sher. «“ 3. Fort Simpson. Lefroy. Stone, Oxford. Glai- « 3. Nottingham, Liverpool, Dunino. Glaisher. « 5. Fort Simpson. Lefroy. “ 6. Fort Simpson. Lefroy. “« 7. Hawarden, Engl. Glaisher. « 8. Fort Simpson. Lefroy. Stonyhurst. Glaisher. “ 9. Fort Simpson. Lefroy. “ 10. Peel’s River, Quebec. Lefroy. “ 10. Fort Simpson, Toronto. Lefroy. “ 1. Peel’s River, Toronto. Lefroy. “ 11. Quebec, Halifax. Lefroy. “ 11. Lewisham, Greenwich. Glaisher. “ 12. Fort Simpson, Slave Lake. Lefroy. « 12. Fort Resolution, Toronto. Lefroy. « 12. At Sea, Ship Eagle, Lt. 48° N. Lg. 30° W. “ 12. Smithsonian Records. 1 And between Quebec and Three Rivers. VOL. X. 36 10. . Fort Simpson. Peel’s River. . Pelly River, Toronto. . Pelly River, Quebec, Lefroy. Stone. Glai- . Fort Simpson, Peel’s River. . Pelly River, Sturgeon River. . Fort Simpson, Peel’s River. 281 Pelly River. Lefroy. Dunino. Glaisher. Lefroy. Lefroy. [sher. Lefroy. Lefroy. Lefroy. *Nov. 13, Peel’s River, Toronto. Lefroy. * « 13. Quebec, Kingston, Halifax. Lefroy. * « 14. Fort Simpson, Toronto. Lefroy. ¥ «@ 14. 14¢ Sea, Ship Senator, Lt. 52°N.Lg. 66° W. * « 14. Smithsonian Records. * « 15. Peel’s River, Fort Simpson. Lefroy. * « 16. Fort Simpson, Quebec, Toronto. Lefroy. * « 17. Peel’s River, Toronto. Lefroy. * “ 18. Peel’s River. Lefroy. Stone,Engl. Glaisher. * « 19. Peel’s River. Lefroy. « 20. Peel’s River, Fort Simpson. Lefroy. “ 21. Peel’s River. Lefroy. « 22. Peels River. Lefroy. “ 23. Peel’s River, Fort George. Lefroy. “ 24. Fort Simpson. Lefroy. * « 25. Fort Simpson, Fort George. Lefroy. “ 27. Toronto. Lefroy. « 28. Peel’s River, Toronto. Lefroy. “ 29. Peel’s River, Fort George, Lefroy, “ 30. Quebec, Toronto. Lefroy. “ 30. Liverpool, Engl. Glaisher. Dec. 1. Fort Simpson. Lefroy. * « 2. Fort Simpson, Kingston. Lefroy. * « 2. Pelly River. Lefroy. * « 3. Fort Simpson, Peel’s River. Lefroy.’ * « 4, Fort Simpson, Peel's River. Lefroy. * « 4. Pelly River. Lefroy. * « 5. Fort Simpson, Peel’s River. Lefroy. * « 5. Pelly River. Lefroy. * « 6. Peel’s River, Pelly River. Lefroy. * « 6. North Shields, Dunino, Engl. Glaisher. * « 7. Fort Simpson, Peel’s River. Lefroy. * « 7%. Pelly River. Lefroy. * « 8. Fort Simpson, Peel’s River. Lefroy. * « 8. Pelly River. Lefroy. * « 9, Fort Simpson, Peel’s River. Lefroy. * « 9. Quebec, Sturgeon River. Lefroy. * « 9. Toronto. Lefroy. Rose Hill. Glaisher. * « 10. Fort Simpson,Peel’s River,Quebec. Lefroy. * x * * * * * * . Pelly River, Quebec. Lefroy. 1 Aurora Australis. * kK kK OK OK & * * * * I oN Oo el el cel ee eel el ed RSENS SSSMNRHDANTAOAAERR bo bo tb hb bt bo RSSSsSSaRgrne MNHANNAMAA AMF wD . Fort Simpson, Peel’s River. . Peel’s River, Fort George, H. B. T. Lefroy. Fort Simpson, Peel's River. . Fort Simpson, Peel's River. Fort George. . Hawarden, Stone, Engl. Fort Simpson, Peel’s River. Fort George, Toronto. ON THE PERIODICITY OF THE AURORA BOREALIS. . At Sea, Ship Plymouth Rock, Lat. 53° N. . Smithsonian Records. . Fort Simpson, Fort Resolution. . Peel’s River. Lefroy. Grantham. Glaisher. . Fort Simpson, Peel’s River. Lefroy. . Between Fort R. and Athabasca. . Fort Simpson, Peel's River. . Quebec, Toronto. . Between Fort R. and Athabasca. . Fort Simpson, Sturgeon River. . Between Fort R. and Athabasca. Lefroy. . At Sea, Ship Plymouth Rock, Lat. 51° N. . Fort George. . Between Fort R. and Athabasca. Lefroy. . Between Fort R. and Athabasca. Lefroy. . Quebec. Lefroy. Stone, Engl. Glaisher. . Between Fort Rk. and Athabasca. . Peel’s River, Fort George. . Between Fort R. and Athabasca. 23. : . Fort Simpson. . Fort Simpson, Fort George. . Chipewyan. . Fort George, Quebec. . Chipewyan, Toronto. . Fort Simpson, Fort Chipewyan. . Quebec, Sturgeon River. . Fort George, Fort Simpson. . Lefroy. . Fort Chipewyan. . Fort George, Fort Chipewyan. [Long. 34° W. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. [ Long. 41° W, Lefroy. Lefroy. Lefroy. Peel’s River. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy, Lefroy. Lefroy. Lefroy. Lefroy. Lefroy 1855. Lefroy. Peel’s River, Fort George. Letroy. Lefroy. Hawarden, Engl. Glaisher. Lefroy. Lefroy. Glaisher. Lefroy. Lefroy. Peel’s River, Fort George. — Lefroy. At Sea, Lt. 42° 25'N. Lg. 68° 58’W. # . Clifton, Rose Hill, Oxford. Glaisher. . Stonyhurst, Dunino. Peel’s River, Fort George, Quebec. Lefroy. . Stonyhurst, Engl. Glaisher. Glaisher. *Jan. * * Kk KOK OK OK * * * KK K K * * KK HK % “ 4) 10. 10. 11. ibB 12. . Fort Simpson, Isle a la Crosse. 1. Fort Simpson. 2. Fort Simpson, Quebec. . En route to Carleton, H. B. T. Lefroy. . Fort Simpson. . Peel’s River. . Fort Simpson, Peel’s River. Lefroy. . En route to Carlton, H. B. T. Lefroy. . Peel’s River, Fort George.. Lefroy. . FortSimpson, Peel’sRiver, Toronto. Lefroy. . Fort Simpson. 31. . Peel’s River, Quebec. Lefroy. . Sturgeon River, Toronto. . Quebec, Sturgeon River. . En route for Swan River. . Kingston. Lefroy. Toronto. Peel’s River. Lefroy. Peel's River, Fort Simpson. Lefroy. Isle @ la Crosse, Quebec. Lefroy. Peel’s River, Fort George. Lefroy. Sturgeon River. Lefroy. Peel’s River, Fort George. Lefroy. . Sturgeon River. Lefroy. . Peel’s River, Fort Simpson. Lefroy. . Quebec, Sturgeon River. Lefroy. . Fort Simpson, Peel’s River. Lefroy. . Peel’s River. Lefroy. Clifton, Hngl. Glaisher. . Fort Simpson, Peel’s River. Lefroy. . Peel’s River. Lefroy. . Isle a la Crosse. Lefroy. . Fort George. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Durham, Grantham, Engl. Glaisher. Lefroy. . Peel’s River. Lefroy. Peel’s River, Fort George. Lefroy. En route for Swan River. Lefroy. . Fort Simpson, Peel’s River. Lefroy. Peel's River, Fort George. Lefroy. . Fort Simpson, Sturgeon River. Lefroy. . Fort Simpson. Lefroy. . Fort Simpson, Peel’s River. Lefroy. . Peel’s River, En route for Swan River. Le. . Fort Simpson, En route for Swan River.Le. . Peel’s River, En route for Swan River.Le. . Quebec, Sturgeon River, Toronto. Lefroy. . Peel’s River. F . Fort Simpson, Peel’s River. . Kingston. Lefroy. Toronto. Lefroy. Lefroy. Kingston. Fort Simpson, Peel’s River. Lefroy. Lefroy. Lefroy. Kingston. * * * ge ik ak te ee . Whitehaven, Engl. . Christiania+ . Fort Simpson, Fort George. . En route for Swan River. . Nottingham, Engl. . Fort Simpson, Peel’s River. . En route for Red River, Fort George. Le. . North Shields, Engl. _Glaisher. . Fort George, Quebec. . North Shields, Engl. . Fort Simpson, Peel’s River, Fort George. . Fort Simpson, Peel’s River. . Fort George. . Fort Simpson, Peel’s River. Lefroy. . Fort George, Quebec. . Fort Simpson, Peel’s River. . Fort George. Lefroy. . Fort Simpson, Fort George. . Fort George. Lefroy. Nottingham. Glaisher. . Fort George. . Fort Simpson, Fort George. . Fort Simpson. Lefroy. Guernsey. Lefroy. . Fort Simpson, Quebec. Lefroy. . Nottingham, Hawarden. . Stonyhurst, Whitehaven. . Christiania. . Fort George. . Stone, Hartwell Factory. Glaisher. . Christiania. (000: “G0 Vente ea aS et cas cotat eaten ee Roa Nore ON THE PERIODICITY OF THE AURORA BOREALIS. Glaisher. Fearnley. Lefroy. Lefroy. Glaisher. Lefroy. Lefroy. Glaisher. [ Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Glaisher. Glaisher. Fearnley. Lefroy. Fearnley. FortSimpson, En route for St.Paul. Lefroy. Fort George. Lefroy. Toronto. Kingston. Fort Simpson, En route forSt. Paul. Lef. Fort George. Lefroy. Toronto. Kingston. Fort Simpson, Fort George. Lefroy. Fort Simpson, Fort George. Lefroy. Quebec, Sturgeon River. Lefroy. Fort George. Lefroy, Toronto. Kingston. Fort Simpson. Lefroy. Fort Simpson, En route for St. Paul. Lef. Fort George, Quebec. Lefroy. Toronto. K. At Sea, Ship New World, Lt. 51° N. Lg. Midhurst, Clifton. Glaisher. [184° W. Hawarden, Durham. Glaisher. Fort Simpson, En route for St. Paul. Lef. Fort George, Quebec, Sturgeon River. Lef. . Clifton, Stonyhurst, Durham. Glaisher. 1 Meteorologische Beobachtungen aufgezeichnet auf Chris- tiania Observatorium. *March 9. * * KK KK HK Ke KK KK KH K xK** KK KK KK KK KK KK * “ . Penetanguishene. . SturgeonRiver. Lefroy. Toronto. Kingston. . At Sea, Ship Roscius, Lt. 42° N. Lg. 56° W. . Smithsonian Records. . Fort Simpson, Fort George, Quebec. Lefroy. . Sturgeon River. Lefroy. Dunino. Glaish. . Fort Simpson, Sturgeon River. . Penetanguishene. Lefroy. Dunino. Glaish. . Fort Simpson. . Quebec, Sturgeon River. . Kingston. . Fort Simpson, Quebec,SturgeonRiver. Lef. . Bicester, Stone, Hartwell Rectory. Glaisher. . Fort Simpson, Fort George. . Fort Simpson, Fort George, Quebec. Lefroy. . Fort Simpson. Lefroy. Holkham,Engl. Gl. . Fort Simpson. . Fort Simpson. . Fort Simpson. . Fort Simpson. . Fort Simpson. Lefroy. Toronto. Kingston. . Stone, Engl. . Fort Simpson. Lefroy. Toronto. Kingston. . Penetanguishene. . Fort Simpson, Sturgeon River. . Fort Simpson, Fort George. . SturgeonRiver. Lefroy. Toronto. Kingston. . Penetanguishene. . Fort Simpson. . Fort Simpson, Fort George. . Penetanguishene. Lefroy. ANNA NAAOIMM ron pp PS woe 283 Fort Simpson, Fort George. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Toronto. Kingston. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Glaisher. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Lefroy. Fort Simpson, Fort George. Lefroy. . SturgeonRiver. Lefroy. Toronto. Kingston. . AtSea, Ship New World, Lt.41°N. Lg.66° W. . At Sea, Ship Yorktown, Lt. 50°N. Lg.28° W. . Smithsonian Records. . Nottingham, Hawarden. . Greenwich, Stone, Hartwell House. Glaish. . Hartwell Rectory, Cardington, Grantham. . Fort Simpson, Sturgeon River. Lefroy. . Penetanguishene.Lefroy. Toronto.Kingston. . Hawarden, Durham, Engl. . Fort George. Lefroy. Toronto. Kingston. . AtSea, Ship Yorktown, Lt. 46°N. Lg.32° W. . At Sea,Ship Mazatlan, Lt. 40°N. Lg.71. . Smithsonian Records. Glaisher. Glaisher. . Stone, Hartwell Rectory, Hawarden. Gi. 284 ON THE PERIODICITY OF THE AURORA BOREALIS. *April 8. At Sea,Ship New World,Lt. 40°N. Lg.68°W.| July 15. Toronto. Kingston. *« 8 At Sea, Ship Yorktown, Lt.46°N. Lg. 35° W. “ 25. Toronto. Kingston. * « 8, Smithsonian Records. *Aug. 7. Christiania. Fearnley. *« 8. Hawarden, Stonyhurst, Durham. Glaisher. “ 19. Christiania. Fearnley. « 9. Fort Simpson. Lefroy. Toronto. Kingston. “ 24. Toronto. Kingston. « 9. At Sea, Ship Yorktown, Lt.454°N. Lg.39° W. “ 25. Christiania. Fearnley. “ 10. FortGeorge, Sturgeon'River, Toronto. Kings-| *Sept. 1. Toronto. Kingston. * * *« 9. Smithsonian Records. [ton.|* “ 931. Zoronto. Kingston. * * « 11. Fort Simpson. Lefroy. * * « 2. Toronto. Kingston. Christiania. Fearnley. “ 12. Fort Simpson. Lefroy. 3 2. Greenwich, Exeter, Clifton. Glaisher. “ 13. Fort Simpson. Lefroy. a 2. Hawarden, Manchester, Engl. Glaisher. “ 14. Fort Simpson. Lefroy. * « 9. Durham, Dunino, Engl. Glaisher. “ 15. Fort Simpson. Lefroy. 3 8. Toronto. Kingston. Christiania, Fearnley. “ 16. Fort Simpson. Lefroy. a 4. Christiania. Fearnley. “ 17. Fort Simpson, Sturgeon River. Lefroy. * “ 10. Christiania. Fearnley. “ 17. Penetanguishene. Lefroy. “ 11. Toronto. Kingston. “ 18. Fort Simpson, Penetanguishene? Lefroy. |* “ 12. Christiania. Fearnley. 3 “ 19. Fort Simpson, Penetanguishene. Lefroy. |* ‘* 18. Toronto. Kingston. Christiania. Fearnley. “ 20. Fort Simpson, Penetanguishene. Lefroy. |* “ 24. Toronto. Kingston. “ 21. Fort Stimpson. Lefroy. “ 27. Christiania. Fearnley. “< 22. Fort Stimpson, Sturgeon River. Lefroy. * “ 28. Toronto. Kingston. «“ 23. Fort Stimpson, Sturgeon River. Lefroy. “ 29. Christiania. Fearnley. “ 24. Sturgeon River. Lefroy. Hawarden. Gl.| Oct. 3. Christiania. Fearnley. “ 25. Fort George, Sturgeon River. Lefroy. “ 9. Toronto. Kingston. «“ 25. Penetanguishene. Lefroy. “ 10. Toronto. , Kingston. “ 29. Fort Simpson, Sturgeon River. Lefroy. “ 11. Toronto. Kingston. “ 29. Penetanguishene. Lefroy. Toronto. Kingston. “ 12. Toronto, Kingston. “ 30. Fort Simpson, Lefroy. “ 17. Toronto. Kingston. Durham. Glaisher. *May 2. Toronto. Kingston. * « 23. Dunino, Engl. Glaisher. « 3. Toronto. Kingston. “ 25. Nottingham, Durham, Engl. Glaisher. * « 4, Toronto. Kingston. “ 925. Dunino, Arbroath, Engl. Glaisher. * « 4. Hawarden, North Shields. Glaisher. “ 99. Whitehaven, Engl. Glaisher. “ 8. Toronto. Kingston. « 30. Dunino. Glaisher. Christiania. Fearnley. «“ 14. Manchester, Engl. Glaisher. * « 31. Toronto. Kingston. * « 94. Toronto. Kingston. Nottingham. Glaisher.|* “ 31. Clifton, Lewisham, Greenwich. Glaisher. “ 28. Toronto. Kingston. * “ 31. Cardington, Norwich, Engl. Glaisher. “ 29. Toronto. Kingston. * « 31. Grantham, Nottingham, Engl. Glaisher. * « 30. Toronto, Kingston. *Nov. 1. Oxford, Engl. Glaisher. *June 1. Toronto. Kingston. * & 2. Whitehaven, Engl. Glaisher. “ 11. Toronto. Kingston. “ 8. Isle of Man, Durham, North Shields, “¢ 22. Greenwich. Glaisher. “ 8. Dunino, Arbroath, Engl. Glaisher. “ 25. Toronto. Kingston. * “ 9, Toronto. Kingston. Nottingham. Glaisher “ 27. Toronto. Kingston. * « 9. Christiania. Fearnley. “ 29. Toronto. Kingston. '« 10. Toronto. Kingston. July 8. Toronto. Kingston. “ 11. Dunino. Glaisher. * “ 10. Toronto. Kingston. * « 19. Christiania. Fearnley. * « 41. Toronto. Kingston. “ 22. Christiania, Fearnley. * « 12. Toronto. Kingston. “ 22. North Shields. Glaisher. oa ~ * s) € ic) * * KK K K & * * * * * “ cc . 22. 1) RAMRoaAnrrN web bd no bo bo bo SSeSaoNQRRES 28. March 2. * * * * * * * *€ cc . Helston, Nottingham. . Toronto.Kingston. Truro, Clifton. Glaisher. . Dunino, Arbroath, Lewisham, Greenwich, . Stonyhurst, Isle of Man, Whitehaven, . Durham, North Shields. . Christiania. . Toronto. Kingston. Durham. Glaisher. . Toronto. Kingston. Greenwich. Glaisher. . Clifton. Glaisher. Christiania. Fearnley. . Toronto. Kingston. . Falmouth. . Falmouth. Glaisher. . Toronto. . Warrington. . Jersey, Clifton. . Jersey. Glaisher. . Toronto. . Christiania. . Toronto. . Toronto. . Christiania. . Toronto. . Toronto. . Christiania. . Christiania. : Christiania. . Toronto. . Christiania. . Christiania. . Christiania. . Christiania. . Christiania. . Toronto. . Toronto. . Christiania. . Toronto. . Toronto. . Toronto. . Christiania. . Toronto. . Christiania. . Christiania. . Toronto. VOL. ON THE PERIODICITY OF Isle of Man, Durham. Glaisher. Stone, Stonyhurst. Glaisher. Toronto. Kingston. Glaisher. Glaisher. Fearnley. Glaisher. Kingston. Glaisher. Glaisher. 1854. Kingston. Fearnley. Kingston. Kingston. Fearnley. Kingston. Kingston. Fearnley. Fearnley. Fearnley. Kingston. Fearnley. Fearnley. an Fearnley. Fearnley. Fearnley. Kingston. Christiania. Fearnley. Christiania. Fearnley. Kingston. Fearnley. Kingston. Kingston. Kingston. Fearnley. Kingston. Fearnley. Fearnley. Kingston. xe 36* THE AURORA BOREALIS. March 22. Christiania. Fearnley. “25. Toronto. Kingston. «25. Christiania. Fearnley. “ 26. Toronto. Kingston. “26. Christiania. Fearnley. * « 27. Toronto. Kingston. * « 28. Toronto. Kingston. * « 29. Toronto. Kingston. * « 30. Toronto. Kingston. April 1. Toronto. Kingston. * « 10. Toronto. Kingston. “ 11. Christiania. Fearnley. “ 14. Christiania. Fearnley. « 15. Christiania. Fearnley. “ 19. Toronto. Kingston. « 19. Christiania. Fearnley. * « 20. Toronto. Kingston. * « 20. Christiania. Fearnley. * « 21. Toronto. Kingston. * « 21. Christiania. Fearnley. «22. Christiania. Fearnley. «23. Toronto. Kingston. “23. Christiania. Fearnley. «24. Christiana. Fearnley. “27. Toronto. Kingston. “28. Toronto. Kingston. May 10. Zoronto. Kingston. * « 15. Toronto. Kingston. * “« 19. Toronto. Kingston. “ 25. Toronto. Kingston. * « 26. Toronto. Kingston. “31? Toronto. Kingston. *June 12. Toronto. Kingston. “23. Toronto. Kingston. *July 3. Toronto. Kingston. * « 10. Toronto. Kingston. “22. Toronto. Kingston. “24. Toronto. Kingston. *Aug. 20. Toronto. Kingston. *Sept. 10. Toronto. Kingston. * “ 15. Toronto. Kingston. * “ “17. Toronto. Kingston. * « 17. Christiania. Fearnley. * « 20. Christiania. Fearnley. * « 21. Toronto. Kingston. * « 21. Christiania. Fearnley. * « 22. Christiania. Fearnley. * « 25. Christiania. Fearnley. * « 26. Toronto. Kingston. * « 26. Christiania. Fearnley. Sept. 27. Toronto. Kingston. Oct. 2. Toronto. Kingston. * « §8. Christiania. Fearnley. “12. Toronto. Kingston. “ 12. Christiania. Fearnley. “ 13. Christiania. Fearnley. “ 17. Toronto. Kingston. “ 18. Toronto. Kingston. * « 23. Toronto. Kingston. Nov. 8. Zoronto. Kingston. “8. Christiania. Fearnley. * « 20. Toronto. Kingston. *Dec. 29. Toronto. Kingston. 1855. Jan. 11. Christiania. Fearnley. “ 12. Christiania. Fearnley. « 24. Toronto. Kingston. Feb. 8. Christiania. Fearnley. « 9. Toronto. Kingston. “« 9. Christiania. Fearnley. * « “11. Toronto. Kingston. * « 11. Christiania. Fearnley. * « 12. Christiania. Fearnley. * “ 14. Christiania. Fearnley. “ 19. Christiania. Fearnley. « 20. Toronto. Kingston. “21. Toronto. Kingston. March 6. Toronto. Kingston. * « 9. Toronto. Kingston. * « 12. Toronto. Kingston. « 15. Toronto. Kingston. * “ 18. Toronto. Kingston. * « 19. Christiania. Fearnley. April 4. Toronto. Kingston. * « 7%. Toronto. Kingston. * “ 7. Christiania. Fearnley. * “« 9. Toronto. Kingston. * « 9. Christiania. Fearnley. “ 11. Toronto. Kingston. * “ 12. Toronto, Kingston. * « 14. Toronto. Kingston. * “ 15. Toronto. Kingston. * “ 15. Christiania. Fearnley. “ 19. Christiania. Fearnley. * “ 20. Toronto. Kingston. “ 22. Toronto. Kingston, *May 1. Toronto. Kingston. “8. Toronto. Kingston. * © 10. Toronto. Kingston. ON THE PERIODICITY OF THE AURORA BOREALIS. | | | | June 8. Toronto. Kingston. “ 10. Toronto. Kingston. “ 16. Toronto. Kingston. «“ 22. Toronto. Kingston. July 19. Toronto. Kingston. « 21. Toronto. Kingston. Aug. 4 Toronto. Kingston. «11. Toronto. Kingston. “14. Toronto. Kingston. * « 17. Toronto. Kingston. ‘© 18. Toronto. Kingston. * « 23. Toronto. Kingston. *Sept.10. Toronto. Kingston. * « “11. Christiania. Fearnley. “ 15. Upsal? Wolf. *« 17. Christiania. Fearnley. “27. Toronto. Kingston. *Oct. 3. Toronto. Kingston. * « 4. Toronto. Kingston. “11. Toronto. Kingston. “ 16. Toronto. Kingston. Upsal ? “ 16. Christiania. Fearnley. “ 18. Christiania. Fearnley. “ 19. Christiania. Fearnley. “ 28. Christiania. Fearnley. «*Nov. 2. Christiania. Fearnley. “ 3. Toronto. Kingston. * « 5. Toronto. Kingston. *« 5. Christiania. Fearnley. « 12. Toronto. Kingston. * « 16. Toronto. Kingston. « 18. Toronto. Kingston. * « 29. Christiania. Fearnley. Wolf. Dec. 4. Toronto. Kingston. 1856. *Jan. 31. Christiania. Fearnley. Heb. 11. Christiania. Fearnley. “ 13. Toronto. Kingston. « 16. Toronto. Kingston. « 20. Toronto. Kingston. “ 23. Toronto. Kingston. « 25. Toronto. Kingston. March1. Christiania. Fearnley. * « 2. Toronto. Kingston. «3. Toronto. Kingston. Ke 5. Toronto. Kingston. w 6. Toronto. Kingston. “ 8. Christiania. Fearnley. Wolf. 1 Nova Acta Upsal., Third Series, Vol. IL. 1 Wochenschrift fiir Astronomie etc. VIII. p. 175. UN THE PERIODICITY OF THE AURORA BOREALIS. March 18. Toronto. Kingston. © 27. Christiania. Fearnley. * « 30. Toronto. Kingston. * « 31. Toronto. Kingston. April 8. Zoronto. Kingston. * « 22. Toronto. Kingston. * « 22. Christiania. Fearnley. « 28. Toronto. Kingston. 29. Toronto. Kingston. June 10. Toronto. Kingston. July 7. Toronto. Kingston. af 9. Toronto. Kingston. « 10. Toronto. Kingston. “ 12. Toronto. Kingston. Aug. 6. Toronto. Kingston. * « 22. Toronto. Kingston. * « 22. Christiania. Fearnley. “ 23. Toronto. Kingston. « 23. Christiania. Fearnley. * « 24. Toronto. Kingston. “« 30. Christiania. Fearnley. * “ 31. Toronto. Kingston. Sept. 1. Christiania. Fearnley. a 8. Toronto. * Kingston. ‘ 8. Christiania. Fearnley, £ 9. Christiania. Fearnley. “ 10. Christiania. Fearnley. “ 16. Toronto. Kingston. “ 26. Toronto. Kingston. “ 26. Christiania. Fearnley. *Oct. 4. Toronto. Kingston. a 6. Christiania. Fearnley. cc 8. Toronto. Kingston. “ 22. Christiania. Fearnley. * « 23. Toronto. Kingston. * « 23. Christiania. Fearnley, Nov. 3. Christiania. Fearnley. x 4. Toronto. Kingston. * 10. Insel Oesel, Russland. “< 22. Christiania. Fearnley. Dec. 1. Christiania. Fearniey. we 4. Christiania. Fearnley. “© 17. Christiania. Fearnley. “23. Toronto. Kingston. « 23. Christiania. Fearnley. « 28. Insel Oesel. Rahr. * « 29. Christiania. Fearnley. Rahr. Heis.? Neue Folge, Jahrgang 1857. Feb. 26. Toronto. Kingston. March 16. Toronto. Kingston. «© 17. Toronto. Kingston. «11. Christiania. Fearnley. «« 28. Ohristiania. Fearnley. Apmil 22. Toronto. Kingston. May 7. Toronto. Kingston. 8. Toronto. Kingston. « 13. Toronto. Kingston. June 11. Toronto. Kingston. July 11. Yoronto. Kingston. “17. Toronto. Kingston. «22. Toronto. Kingston. «© 25. Toronto. Kingston. «© 28. Toronto. Kingston. Aug. 26. Toronto. Kingston. *Sept. 3. Toronto Kingston. ome i 3. Christiania. Fearnley. ¥ « 10. Toronto. Kingston. « 14. Toronto. Kingston. «© 18. Christiania. Fearnley. * « 19. Christiania. Fearnley. «21. Christiania, Fearnley. «« 23. Toronto. Kingston. «23. Christiania. Fearnley. «© 25. Toronto. Kingston. «29. Toronto. Kingston. Oct. 17. Toronto. Kingston. «23. Toronto. Kingston * « 24. Christiania. Fearnley. *Nov. 9. Christiania. Fearnley. * “ 10. Christiania. Fearnley. * « 11. Insel Oesel. Rahr. * “ 11. Christiania. Fearnley. “16. Insel Oesel. ahr. “ 16. Christiania. . Fearnley. * “ 17. Toronto. Kingston. * “ 23. Toronto. Kingston. *Dec. 17. Insel Oesel. Rahr. * « 17. Brussels. Quetelet. * « 17. Christiania. Fearnley. * “« 20. Toronto. Kingston. * « 22. Toronto. Kingston. ‘ 23. Christiania. Fearnley. “ 27. Christiania. Fearnley. 1 Wochenschrift fiir Astronomie ete. I. 96, &e. Heis.* 287 Neue Folge, Jahrgang 288 Ok eae Oe Fe x * *¥ * KK HK KK K * xk eK KR KK KR RK HH 1 Light over the firmament. Doubtful whether it was an aurora. . Christiania. . Christiania. . Toronto. . Toronto. . Toronto. . Christiania. . Toronto. . Christiania. 18. *March 1. * . Christiania. . Toronto. . Insel Oesel. . Insel Oesel. . Christiania. . Toronto. . Christiania. . Toronto. . Rose Hill, Engl. . Christiania. . Toronto. . Toronto. . Many places in England. Glaisher. . Clifton. Glaisher. Insel Oesel. . Silloth. Glaisher. Christiania. Fearnley. . Toronto. 4. Christiania. ON THE PERIODICITY 1858. . Christiania. Fearnley. . Toronto. . Toronto. . Insel Oesel. . Christiania. Kingston. Kingston. Rahr. Dorpat. Fearnley. Heis. . Christiania. Fearnley. Fearnley. Fearnley. Christiania. Christiania. Christiania. Kingston. Kingston. Fearnley. Fearnley. Fearnley. Christiania. Fearnley. Kingston. Fearnley. Toronto. Kingston. Insel Oesel. Christiania. Fearnley. Rahr. Kingston. Fearnley. Toronto. Kingston. Insel Oesel. Rahr. Fearnley. Toronto. Kingston. Kingston. Rehr. Rahr. Fearnley. Kingston. Fearnley. Kingston. Glaisher. Fearnley. Kingston. Insel Oesell. Many places in England. Glaisher. . Skive, North Jutland, Dresden. Heis. Gottingen, Naugard. Heis. . Christiania. Kingston. . Christiania. Fearnley. Rahr. Kingston. Fearnley. . Toronto. Kingston. Rahr. Fearnley. Jlunster. Heis. | | | April 21. Paris. Raillard, Heis. “ 24. Fairlight, Engl. Glaisher. “ 29. Clifton, Engl. Glaisher. May 1. Toronto, Kingston. Insel Oesel. Rahr. “ 2. Clifton, Engl. Glaisher. “ 6. Clifton, Engl. Glaisher. “ 7. Toronto. Kingston. “ 7. Clifton, Oxford, Engl. Glaisher. “ 8. Toronto. Kingston. Clifton. Glaisher. “ 9. Toronto. Kingston. “ 10. Clifton, Engl. Glaisher. “ 21. Toronto. Kingston. June 3. Toronto. Kingston. “ 6. Oxford, Engl. Glaisher. “ 7, Toronto. Kingston. “ 18. Toronto. Kingston. “ 23. Toronto. (Kingston. July 4. Toronto. Kingston. * «“ §. Toronto. Kingston. “ 6. Toronto. Kingston. ““ 12. Toronto. Kingston. “ 15. Toronto. Kingston. Aug. 13. Toronto. Kingston. “ 15. Toronto. Kingston. “ 16. Toronto. Kingston. * « 21. Christiania. Fearnley. Heis. “ 25. Toronto. Kingston. “ 95, Christiania. Fearnley. * « 30. Toronto, Kingston. * « 31. Toronto. Kingston. *Sept. 1. Toronto. Kingston. * «“ 7. Toronto. Kingston. * «“ 8. Toronto. Kingston. “ 10. Toronto. Kingston. * « 12. Toronto. Kingston. “ 13. Toronto. Kingston. “ 13. Christiania. Fearnley. Heis. “ 20. Toronto. Kingston. “ 20. Christiania. Fearnley. Heis. “ 21. Christiania. Fearnley. Heis. « 22. Toronto. Kingston. “ 24. Christiania. Fearnley. Heis. Oct. 1. Toronto. Kingston. * « 2. Toronto. Kingston. “ 2. Christiania. Fearnley. Heis. “ 4. Toronto. Kingston. “5. Toronto. Kingston. “ 6. Christiania. Fearnley. Heis. “ 8. Christiania. Fearnley. Heis. « 9. Toronto. Kingston. OF THE AURORA BOREALIS. ON THE PERIODICITY OF *Oct. 9. Christiania. Fearnley. Heis. * “ 10. Toronto. Kingston. “© 13. Christiania. Fearnley. Heis. “ 18. Toronto. Kingston. “ 18. Christiania. Fearnley. “ 19. Christiania. Fearnley. Heis. “ 26. Toronto. Kingston. * « 2%. Toronto. Kingston. * « 99. Christiania. Fearnley. Heis. * “ 30. Toronto. Kingston. *Nov. 7. Toronto. Kingston. “ 10. Toronto. Kingston. “ 10. Christiania. Fearnley. Teis. “ 13. Christiania. Fearnley. Heis. “ 15. Toronto. Kingston. “ 19. Christiania. Fearnley. Heis. *Dec. 4. Gaesdonck bei Goch. Heis.* * « 4. Munster, Jung-Bunzlau, Bohemia. Heis. “ 22. Toronto. Kingston, * « 94. Toronto. Kingston. Christiania. Fearnley. «“ 29. Christiania. Fearnley. 1859. *Jan. 1. Havre. leis.’ * « 9, Isle Jesus. Smallwood. * « 10. Isle Jesus. Smallwood. * « 11. Isle Jesus. Smallwood. * « 41. Christiana. Fearnley. “ 15. Christiania. Fearnley. “ 22. Helston, Engl. Glaisher. “ 93. Rose Hill, Engl. Glaisher. * “ 28. Christiania. Fearnley. *Feb. 1. Isle Jesus. Smallwood. « 6. Isle Jesus. Smallwood. * « 9. Toronto. Kingston. * « 9, Many places in England. Glaisher. * « 29. Isle Jesus. Smallwood. * « 99. Many places in England. Glaisher. * « 92. Christiania.. Fearnley. * « 23. Christiania. Fearnley. * « 23. Rendsburg, Hamburg. Heis. * « 23. Naugard, Prague. Weis. * « 93. Copenhagen. D’Arrest. Dorpat. Ballot.? 1 Wochenschrift fiir Astronomie etc. 11. 30, &e. Neue Folge, Jahrgang 2 Havre was put into painful agitation on New Year’s even- ing by the cry of fire. color. The heavens glowed with a fiery red The whole fire department turned out and found for- | tunately nothing to extinguish but an aurora. — Wochenschrift fiir Astronomie, IT. 40. 3 Nederlandsch Meteorologisch Jaarboek, 1859, p. 538. fe x : a. vou 37 THE AURORA BOREALIS. - 289 “ * * * * . 23. 24. 24. 24. 24. 24, 25. 25. 25. 26. 26. 27. 28. March 1. . Isle Jesus. . Rose Mill, Hingl. . Christiania. . Christiania. . Isle Jesus. . Toronto. . Isle Jesus. . Toronto. . Toronto. . Christiania. . St. Paul’s Parsonage, Engl. . Christiania. . Toronto. . Christiania. . Many places in England. Glaisher. . Isle Jesus. . Nottingham, Hawarden, Engl. . Toronto. . Hawarden, Engl. . Toronto. . Isle Jesus. . Many places in England. Giaisher. . Christiania. . Toronto. . Isle Jesus. . St. Paul’s Parsonage, Engl. . Christiania. . Isle Jesus. . England. Many places in England. Glaisher. Toronto. Kingston. Isle Jesus. Smallwood. Christiania. Fearnley. Many places in England. Glaisher. Dorpat. Miidler. Ballot. Heis. Isle Jesus. Smallwood. Nottingham, Stonyhurst, Engl. Glaisher. Dorpat. Miidler. Ballot. Heis. Clifton, Manchester, Engl. Glaisher. Dorpat. Midler, Ballot. Heis. Christiania. Fearnley. Toronto. Kingston. Toronto. Kingston. Smallwood. Isle Jesus. Smallwood. Glaisher. Fearnley. Fearnley. Smallwond. Kingston. Smallwood. Kingston. Kingston. Fearnley. Glaisher. Fearnley. Kingston. Fearnley. Smallwood. Glaisher. Kingston. Glaisher. Kingston. Smallwood. Fearnley. Kingston. Smallwood. Glaisher. Fearnley. Smallwood. Glaisher. Smallwood. Fearnley. Smallwood. Kingston. Kingston. Smallwood Tsle Jesus. Christiania. Isle Jesus. Toronto. Toronto. Isle Jesus. * * * K kK K KF *& * * * * K * * 1 Amer. Journ. Sci. . Isle Jesus. . Toronto. . Christiania. . Toronto. Kingston. /sle Jesus. Smallwood. . Strehla, Kremsmiinster. . Christiania. . England. Glaisher. . Munich. . Prague, Leipsic. . Christiania. . England. . Toronto. . Christiania, Fearnley. Munster. Ueis. . Christiania. 5. Christiania. . Toronto. Kingston. Hngland. Glaisher. . Kremsmiinster. - England. Glaisher. . Isle Jesus. Smallwood. . England. . Toronto. . Isle Jesus. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. 2. Toronto. . Isle Jesas. . Wemlinghoven, Rheinprovince. . Toronto. . Toronto, . Toronto. . Isle Jesus. Smallwood. . Toronto. . Isle Jesus. Smallwood. . Toronto. . Isle Jesus. Smallwood. . Toronto. Kingston. Isle Jesus. . At Sea, Lat. 30°. Long. 45°. . At Sea, Lat. 26°. Long. 46°. 28. . Australia. . Christiania. . Rafe. ON THE PERIODICITY OF Smallwood. Kingston. Fearnley. Teis. Fearnley. Ballot. Heis. Fearnley. Munster. Glaisher. Kingston. Lamont. Heis. Fearnley. Fearnley. Toronto. Kingston. Isle Jesus. Smallwood. Heis. Ballot. Glaisher. Kingston. Smallwood. Kingston. ‘ Kingston. Kingston. Kingston. Kingston. Kingston. Kingston. Smallwood. Toronto. Heis. Kingston. Kingston. Kingston. Kingston. Kingston. Smallwood. | Fitz Roy." Fitz Roy. Fitz Roy. At Sea, Lat. 51°. Long. 10°. Glaisher. Fearnley. Heer. Holland.? New Series, XXXII and 78. 2 Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, I. 297, 301, 340, 385. Ill. 127. IV. 390. * eK KK KK KK KK K KK KH KH KK K * * KF K K * RM is] i=] a * * * # *& * * * *Aug. ‘ 28. 29. 29. 29. 29. 30. 1c) pare n n AOOOFrF EF FP wWwWHwwwdrnwnndnd nN bNp Fe 6. — a 18. 28. . Grantham, . Toronto. . Clifton, Durham, . Toronto. . Hamburg, Kremsmiinster. . Clifton, Durham, Engl. . St. Petersburg, Hanem. . Christiania. Fearnley. Stockholm. Heis. ). Isle Jesus. . England, Holland. Heis. . Cologne, Hamburg, Clement. . Kremsmunster. . Hiilsber Crefeld. . Elberfeld. Heis. . Christiania. Fearnley. . Toronto. . Christiania. Fearnley. Hamburg. Clemexs. . Toronto. . Isle Jesus. . Dorpat. . Gaesdonck, Hamburg. Heis. . Christiania. Fearnley. Paris. Goldsmith. . Kremsmiinster. Reslhuber. Coesfeld. Heis. . Naugard. Winkler. . Lymington, Hants. THE AURORA BOREALIS. Heis. Heis, Belgium, France, Italy. Leipsic, Munich. Ballot. Isle Jesus. Smallwood. Toronto. Kingston. Rome, Prague. Heis. Australia. Glaisher. Brussels. Ballot. Heis. Grantham, Engl. Vischel? Heis. ingl. Vischel. Heis. Kingston. Grantham. Heis. Cracow. Ballot. Christiania. Hansteen. . Toronto. Kingston. Isle Jesus. Smallwood. Christiania. Fearnley. rremsmiinster. Heis.4 Cracow. Ballot. Teis. At Sea, Lat. 34°. Long. 44°. Fitz Roy. At Sea, Lat. 34°. Long. 33°. Fitz Roy. At Sea, Lat. 24°. Long. 36°. Fitz Roy. Kingston. : Christiania. Fearnley. Heis. Heis. Cracow, Dorpat, Stockholm. Ballot. . Toronto. Kingston. Christiania. Fearnley. . Clifton, Tottenham, Grantham, Durham. . Gotlenburg, Neumark. Heis. . Toronto. Kingston. Christiania. Fearnley. Heis. Hamburg, Munster, Naugard. Heis. Toronto. Kingston. Isle Jesus. Smallwood. Isle Jesus. Smallwood. Smallwood. Heis. Ballot. Becket. Heis. Kingston. Kingston. Smallwood. Munich. Ballot. Lamont. Heis. Heis. Frier. Campbell. 1 Wochenschrift fiir Astronomie etc., Neue Folge, Jairgan g Il. 16 &e. *Oct. 2. Toronto. Kingston. Isle Jesus. Smallwood. * « 2. Toulouse, Cassel, Madrid. Heis. * « 3. Toronto. Kingston. “ 6. Christiania. Fearnley. “ 12. Cracow, Leipsic, Putbus. Ballot. Te FE es RR) cae, RAE GE RS IE Sa ae . Christiania? Hansteen. Dresden. Groth, . Hervest. Eming. Lichtenberg. Bornitz. . Naugard. Klopsch. . Christiania. “ 18. Toronto. Kingston. Isle Jesus. Smallwood. “ 18. Christiania. Fearnley. 18. Haparanda. Ballot. “ 19. Isle Jesus. Smallwood. “ 19. Dorpat. Heis. Paris. Ballot. «20. Toronto. Kingston. “ 20. Christiania. Fearnley. . Toronto. Kingston. Christiania. Fearnley. ON THE PERIODICITY OF Rome. Heis. Fearnley. “ 22. Isle Jesus. Smallwood. “ 22. Christiania. Fearnley. “ 23. Christiania. Fearnley. “ 24. Peckeloh. Weber. Heis. “ 27. Christiania. Fearnley. “ 31. Christiania. Fearnley. Nov. 5. Toronto. Kingston. “ 12. Christiania. Fearnley. Dorpat. Ballot. * “ 13. Toronto. Kingston. _ “ 18. Christiania. Fearnley. “ 16. Haparanda. Ballot. * « 24. Christiania. Fearnley. “ 99. Christiania. Fearnley. Dec. 6. Haparanda, Rome. Ballot." * « 13. Toronto. Kingston. Naugard. Heis. * “ 13. Christiania. Fearnley. * “ 13. Haparanda. Ballot. * « 14. Toronto. Kingston. * « 14. Christiania. Fearnley. * « 15. Toronte. Kingston * “ 16. Christiania. Fearnley. “ 22. Isle Jesus. Smallwood. “ 22. Gresten, Austria. Heis. * “ 23. Toronto. Kingston. * « 26. Isle Jesus. Smallwood. « 28. Isle Jesus. Smallwood. * « 30. Toronto. Kingston. 1860. Jan. 11. Toronto. Kingston, “ 13. Haparanda. Ballot. “ 16. Christiania. Fearnley. 3 1 Nederlandsch Meteorologisch Jaarboek, 1860, p. 302. THE AURORA BOREALIS. *Jan. * * * * KF K® K * * & & KH KH & *F. KF * “ “ 20. 20. 20. . Toronto. . Christiania. . Toronto. 28. Toronto. . Christiania. Fearnley. Stockholm. Ballot. . Stockholm. . Isle Jesus. . Christiania. . Toronto. . Isle Jesus. . Toronto. . Isle Jesus. . Toronto. Kingston. Haparanda. Ballot. . Isle Jesus. . Toronto. . St. Petersburg. 291 Isle Jesus. Smallwood. Toronto. Kingston. Haparanda. Ballot. Kingston. Fearnley. Kingston, Kingston. Heis. Ballot. Christiania. Fearnley. Nottingham. Ballot. . Toronto. Kingston. Stockholm. Ballot. . Isle Jesus. : . Haparanda, Stockholm. . Isle Jesus. . Haparanda. . Haparanda. . Isle Jesus. . Toronto. . Haparanda. . Christiania. . Isle Jesus. Smallwood. Dorpat. . Toronto. . Isle Jesus. . Christiania. Smallwood. Ballot. Smallwood. Ballot. Ballot. Smallwood. Kingston. Ballot. Heis. Fearnley. Ballot. Kingston. Smallwood. Fearnley. Ballot. Smallwood. Kingston. Fearnley. Kingston. Smallwood. Kingston. Smallwood. Nottingham. Toronto. Smallwood. Kingston. Ballot. Isle Jesus. Smallwood. . Christiania. Fearnley. Stockholm. Ballot. . St. Petersburg, Nottingham. Ballot. . Toronto. . Isle Jesus. . Toronto. . Christiania. Fearnley. Nottingham. Ballot. . Toronto. . Isle Jesus. . Christiania ? . Cuba. Poey. Heis. . Nottingham. Ballot. . Toronto. Kingston. Dresden. Fischer. . Christiania. Kingston. Smallwood. Kingston. Kingston. Smallwood. Ballot. Fearnley. 292 ON THE PERIODICITY OF THE AURORA BOREALIS. *March 27. Toronto. Kingston. Sweden. Heis.1 | *July 17. Toronto. Kingston. * « 98. Brussels. Quetelet. Heis. * “ 17. Near Cape Chudleigh. Venable. * “ 29. Christiania. Fearnley. “ 18. Isle Jesus. Smallwood. April 8. Christiania. Hansteen. ; * “ 19. Toronto. Kingston. ance 9. Toronto. Kingston. * “ 49. Isle Jesus. Smallwood. oy 9. Isle Jesus. Smallwood. “ 21. Toronto. Kingston. nF IL 9. Christiania. Fearnley. Crefeld. Heis. “ 23. Isle Jesus. Smallwood. * 6 9. Skive, North Jutland, Munster. Heis. “ 25, Near Cape Chudleigh. Venable. eg 9. Wiedenbruck. Heising. Heis. “ 27. Toronto, Kingston. . er 9. Nottingham. Ballot. Galditz. Heis. “ 29. Near Cape Chudleigh. Venable. aber 9. Hamburg. Hamm. Heis. Aug. 1. Near Cape Chudleigh. Venable. “ 10. Christiania. Fearnley. “ 2. Near Cape Chudleigh. Venable. “11. Toronto. Kingston. “« 4, Isle Jesus. Smallwood. “ 11. Christiania. Fearnley. «“ 5, Isle Jesus. Smallwood. * « 12. Toronto. Kingston. * « 6. Toronto. Kingston. * « 13. Isle Jesus. Smallwood. Werden. Heis.|* “ 6. Near Cape Chudleigh. Venable. * “ 14, Toronto. Kingston. * « 8. Toronto. Kingston. * “ 44. Isle Jesus. Smallwood. * “« 8, Isle Jesus. Smallwood. “ 16. Christiania. Fearnley. * «“ 8. Prague, Dresden, Braunsberg. Heis. “ 16. Nottingham. Ballot. Munster. Heis. |* “ 9. Toronto. Kingston. “ 18. Toronto. Kingston. * « 9, Isle Jesus. Smallwood. * « 18. Isle Jesus. Smallwood. * «“ 9. Kremsmiinster. Ballot. Heis. * « 18. Christiania. Fearnley. * “ 10. Toronto. Kingston. Dresden. Fischer. “ 19. Christiania. Fearnley. * « 10. St. Petersburg, Emden. Ballot. Heis. * “ 11. Toronto. Kingston. “, 26. Toronto. Kingston. * «© 11. Isle Jesus. Smallwood. May 11. Toronto. Kingston. * « 12. Isle Jesus. Smallwood. “ 12. Toronto. Kingston. * « 12. Weenen, Kremsmiinster. Ballot. Heis. “ 12. Isle Jesus. Smallwood. * « 12. Orenbourg. Anitschkoff. « 14. Toronto. Kingston. * « 413. Toronto. Kingston. * ‘© 13. Christiania. Fearnley. “© 15. Christiania. Fearnley. “« 16. Isle Jesus. Smallwood. “ 16. Stockholm. Ballot. . Christiania. Fearnley. “© 18. Toronto. Kingston. Stockholm. Ballot. « 18. Isle Jesus. Smallwood. “« 19. Christiania. Fearnley. «21. Isle Jesus. Smallwood. * « 22. Toronto. Kingston. * « 92. Isle Jesus. Smallwood. “ 18. Toronto. Kingston. “ 23. Toronto. Kingston. “ 24. Toronto. Kingston. «“ 27. Toronto. Kingston. June 9. Toronto. Kingston. « 10. Toronto. Kingston. * « 30. Near Cape Chudleigh. Venable.? July 1. Near Cape Chudleigh. Venable. B 2. Near Cape Chudleigh.. Venable. Lg 4. Near Cape Chudleigh. Venable. L 8. Near Cape Chudleigh. Venable. * * & & * for) « 23. Toronto. Kingston. “ 11. Toronto. Kingston. *Sept. 6. Toronto. Kingston. « 41. Near Cape Chudleigh. Venable. * « 6. Isle Jesus. Smallwood. «© 12. Toronto. Kingston. * “ 6. Christiania. Fearnley. «“ 12. Near Cape Chudleigh. Venable. * « 7. Christiania. Fearnley. “ 16. Near Cape Chudleigh. Venable. * « 8. Toronto. Kingston. 1 Wochenschrift fiir Astronomie ete. Neue Folge, Jahrgang SC pier IV. 98, &. i ; : >| * “ 10. Toronto. Kingston. 2In Labrador. See U. S. Coast Survey Reports, 1860, * « 10. Isle Jesus. Smallwood. pp. 258, 9. * “ 10. Christiania. Fearnley. ON THE PERIODICITY OF THE AURORA BOREALIS. Sept. 11. Christiania. Fearnley. * « 15. Toronto. Kingston. * * « 15. Isle Jesus. Smallwood. * « 16. Isle Jesus. Smallwood. Moscow. * « 16. Christiania. Fearnley, * « 17. Isle Jesus. Smallwood. « 19. Toronto. Kingston. * “ 25. Toronto. Kingston. Oct. 4 Christiania. Fearnley. «“ 4, Stockholm. Ballot. * « 8. Isle Jesus. Smallwood. * « 41. Isle Jesus. Smallwood. “ 12. Isle Jesus. Smallwood. « 13. Isle Jesus. Smallwood. « 15. Haparanda. Ballot. “ 16. Christiania. Fearnley. «“ 17. Christiania. Fearnley. “ 19. Putbus. Brehmer. Ballot. Noy. 2. Nottingham. Ballot. * « 4, Toronto. Kingston. * « 4, Isle-Jesus. Smallwood. e “ 1. Christiania. Fearnley. *Dec. 9. Isle Jesus. Smallwood. * « 10. Toronto. Kingston. * © 10. Christiania. Fearnley. * « 15. Toronto. Kingston. “ 16. Christiania. Hansteen. « 21. Christiania. Fearnley. «“ 24. Christiania. Fearnley. « 25. Christiania. Hansteen. 1861. Jan. 4. Christiania. Fearnley. « 4. Isle Jesus. Smallwood. “ 6. Aalesund. Fearnley.? « 6. Christiania. Fearnley. © 10. Isle Jesus. Smallwood. * « 22. Dorpat. Heis. Ballot. « 23. Dorpat, Heis. Ballot. «“ 24. Munster. Ballot. Heis. “ 24. Peckeloh, Elberfeld. Heis. Feb. 1. Christiania? Hansteen. «“ 6. Aalesund. Fearnley. “ 8. Aalesund. Fearnley. “ 10. Toronto. Kingston. “ 10. Christiania. Fearnley. “ 11. Christiania. Fearnley. “ 11. Aalesund. Fearnley. Ballot. 1 Meteorologiske Iagttagalser paa Fem Telegrafstationer ved Norges Kyst, p. 2. VOL. X. 37* * * KK eK Ke KK He HK * * * * * * * * KK K * . Christiania. . Isle Jesus. Smallwood. . Christiania. 293 . Isle Jesus. Smallwood. . Toronto. Kingston. Isle Jesus. Smallwood. . Christiania. . Toronto. Kingston. Aalesund. Fearnley. . Isle Jesus. Smallwood. . Aalesund. Fearnley. . Christiania. . Toronto. . Copenhagen, Montpellier. Fearnley. Fearnley. Kingston. Ballot. Putbus. Heis. . Netherlands. Ballot. . Aalesund, Mendal. . Christiania, Sandésund. Fearnley. . Peckeloh. Weber. Fearnley. Heis. Toronto. Kingston. Isle Jesus. Smallwood. . Aalesund. Fearnley. Toronto. Kingston. Isle Jesus. Smallwood. . Aalesund. Fearnley. Toronto. Kirtgston. . Isle Jesus. Smallwood. - Aalesund. Fearnley. . Christiania. . Toronto. . Aalesund, Christiania. . Isle Jesus. Smallwood. . Toronto. . Isle Jesus. Smallwood. - Toronto. Kingston. Fearnley. Kingston. Fearnley. Kingston. Toronto. Kingston. Isle Jesus. Smallwood. Christiania. Fearnley. Netherlands. Ballot. Toronto Kingston. Isle Jesus. Smallwood. Christiania. Fearnley. Toronto. Kingston. Isle Jesus. Smallwood. Isle Jesus. Smallwood. Fearnley. Fearnley. Toronto. Kingston. . Isle Jesus. Smallwood. . Munster. . Haparanda. Ballot. . Christiania. . Christiania. Fearnley. Heis. Netherlands. Ballot. Fearnley. 1 Nederlandsch Meteorologisch Jaarboek, 1861, pp. 284, 285. 294 April 25. 26. 28. 29. 4. 8. 15. 16. ITs 12. 13. 29. “ “ “ * K * F * * oh 12. 118+ 25. . Toronto. . Isle Jesus. . Toronto. . Isle Jesus. Smallwood. . Isle Jesus. Smallwood. . Isle Jesus. . Toronto. . Toronto. . Isle Jesus. . Christiania. . Toronto. . Toronto. . Isle Jesus. . Toronto. . Christiania. . Isle Jesus. Smallwood. . Christiania. . Dorpat. . Munster. Ballot. . Toronto. . Isle Jesus. Smallwood, . Isle Jesus. . Netherlands. . Haparanda. . Utrecht. . Christiania. . Toronto. . Isle Jesus. . Christiania. . St. Petersburg, Stockholm. Ballot. Heis. 10. 10. 1 Wochenschrift fiir Astronomie etc., Neue Folge, Jahrgang V. 387 &e. ON Ballot. Ballot. Ballot. rs Ballot. Kingston. Kingston. Kingston. Kingston. Kingston. Toronto. Kingston. Toronto. Kingston. Isle Jesus. Smallwood. Toronto. Kingston. Isle Jesus. Smallwood. Isle Jesus. Smallwood. Isle Jesus. Smallwood. Kingston. Smallwood. Kingston. Prague. Prague. Prague. Prague. Toronto. Toronto. Toronto. Toronto. Toronto. Smallwood. Kingston. Kingston, BAL Smallwood. Fearnley. Kingston. Kingston. Smallwood. Kingston. Fearnley. Fearnley. Ballot. Kingston. Smallwood. Ballot. Ballot. Heis. Fearnley. Kingston. Smallwood. Fearnley. Dorpat. Heis.? Heis, Utrecht, Netherlands. Sandésund. Fearnley. Ballot. Heis. Oct. 11. uO ale} cca. 24. “ 24. “ 25. a fe Coals CO Ash ‘c 28. Ot ale *Noy.7. * * * * * * 6 ( “e sy “ S fs IP « 20. « 93, ce 26. 730: *Dec,1? Toronto. Kingston. “ 2 “ 8. THE PERIODICITY OF THE AURORA BOREALIS. Haparanda. Ballot. Heis. Toronto. Kingston. Toronto. Kingston. Toronto. Kingston. Isle Jesus. Smallwood. Toronto. Kingston. Toronto. Kingston. Christiania, Fearnley. Isle Jesus. Smallwood. Haparanda. Haparanda. Ballot. Heis. Isle Jesus. Smallwood. Toronto. Kingston. Aalesund. Fearnley. Ebstorf, Netherlands. Ballot. Heis. Isle Jesus. Smallwood. Christiania. Fearnley. Aalesund. Fearnley. Isle Jesus. Smallwood. Christiania. Fearnley. Christiania. Fearnley. Christiania. Fearnley. StockIcolm. Heis. Heis. Dessau, Prague. Dorpat. Ballot.? “ 3? Stockholm, Peckeloh. Heis. * 6 4 * 6 4. “ 6. “ re abe Okt 19. * 6 19. =F 0G IG). “ 20. « 20. “ 20. Os ale “ 23. “24, «6 26. « 30. *Jan. af * 6 ale * 6 Oy * 6 or “&@F 6. ce 1 Nederlandsch Meteorologisch Jaarboek, 1862, pp. 296, 319. . Toronto. Kingston. Gaesdonck. Heis. Netherlands. Ballot. Carrow. Heis, Aalesund. Fearnley. Aalesund. Fearnley. Isle Jesus. Smallwood. Isle Jesus. Smallwood. Stockholm, Haparanda. Aalesund.. Fearnley. Mandal, Sandésund. Fearnley. Toronto. Kingston. Isle Jesus. Smallwood. Christiania? Fearnley. Basle. Toronto. Kingston. Dresden. Heis. Dresden. Heis. Peckeloh. Weber. Ballot. Heis. Heis. Heis. Aalesund. Fearnley. 1862. Toronto. Kingston. Stockholm. Heis. Ballot. Toronto. Kingston. Isle Jesus. Smallwood. Aalesund. Fearnley. Toronto. Kingston. Jan. March 4. ON THE PERIODICITY OF 13. Isle Jesus. Smallwood. “ 22. Aalesund. Fearnley. “ 24. Isle Jesus. Smallwood. » 29. Toronto. Kingston. * « °31. Haparanda? Heis. Aalesund. Fearnley. *Feb. 2. Aalesund. Fearnley. “ 6. Aalesund. Fearnley. “ 20. Isle Jesus. Smallwood. “ 21. Minster, Peckeloh, Gaesdonck. Heis. «“ 21. Aalesund. Fearnley. Skudesnes. “ 21. Netherlands. Ballot. “ 22. Athens. Schmidt. Heis. “ 24, Aalesund. Fearnley. “ 24. Skudesnes, Sandésund. Fearnley. * “ 28. Toronto. Kingston. Netherlands. Ballot. Munster. Heis. «“ 5. Peckeloh. Weber? “ 14, Athens. Schmidt. Heis. “ 19. Isle Jesus. Smallwood. “ 25. Toronto. Kingston. “ 26, Isle Jesus. Smallwood. « 27. Toronto. Kingston. April 1. Toronto. Kingston. Z “ 2. Peckeloh. Weber. Heis. « 3. Toronto. Kingston. “ 10. Toronto. Kingston. “ 13. Pays. Heis: “ 15. Toronto. Kingston. Isle Jesus. Smallwood. “ 29. Toronto. Kingston. May 2. Milan. Schiaparelli. « 6. Isle Jesus. Smallwood. “« 6. Toronto. Kingston. “ 19. Munster. Heis. Wilna. Gussew. Heis. “ 19. Milan. Schiaparelli. “ 20. Milan. Schiaparelli. «21. Toronto. Kingston. «“ 23. Toronto. Kingston. « 30. Toronto. Kingston. «¢ 30. Isle Jesus. Smallwood. “ 31. Toronto. Kingston. June 4. Netherlands. Ballot. “ 13. Toronto. Kingston. “ 19. Toronto. Kingston. July 5. Toronto. Kingston. Netherlands. Ballot. “ 9. Toronto. Kingston, “ 17. Toronto. Kingston. “ 19. Senftenberg. Brorsen. Heis. « 23. Toronto. Kingston. 1 Wochenschrift fiir Astronomie etc., Neue Folge, Jahrgang VI. 104. THE AURORA BOREALIS. July * * * KK K K K K K * 24, 27. . Toronto. . New York, U.S. A. Heis. Havana. Poey. . Isle Jesus. . Munster. . Munich. . Netherlands. . Isle Jesus. . Toronto. . Toronto. . Isle Jesus. . Isle Jesus. . Toronto. Kingston. . Isle Jesus. Smallwood. . Toronto. Kingston. Netherlands. . Christiania. . Milan. . Toronto. . Senflenberg. Brorsen. . Peckeloh. Weber. - Milan. . Toronto. Kingston. Isle Jesus. Smallwood. . Isle Jesus. . Isle Jesus. . Toronto. . Peckeloh. . Senftenberg. Brorsen. . Isle Jesus. . Aalesund. Fearnley. . Toronto. . Isle Jesus. . Isle Jesus. . Toronto. . Isle Jesus. . Peckeloh, Stockholm? Heis. . Peckeloh. Weber. . Mandal. 295 Toronto. Milan. Kingston. Schiaparelli. Kingston. ({Heis. Smallwood. Heis. Peckeloh. Weber. Heis. Heis. Milan. Schiaparelli. Ballot. Smallwood. Kingston. Kingston. Smallwood. Smallwood. Ballot. Fearnley.? Schiaparelli. Kingston, Kingston. Kingston. Toronto. Toronto. Heis. Heis. Schiaparelli. Toronto. Kingston. Toronto. Kingston. ‘Toronto. Kingston. Isle Jesus. Smallwood. Toronto. Kingston. Isle Jesus. Smallwood. Peckeloh. Weber. Heis. Toronto. Kingston. Smallwood. Smallwood. Kingston. Stockholn. Weber. Heis. Heis. Ballot. Toronto. Kingston. Smallwood. Kingston. Smallwood. Smallwood. Kingston. Smallwood, Heis. Fearnley. 1 Probably a misprint for August 29 or August 30. 296 ON THE PERIODICITY OF THE AURORA BOREALIS. *Oct. 4. Toronto. Kingston. * « 4, Isle Jesus. Smallwood. “ 9. Utrecht. Heis. * « 11. Toronto. Kingston, Aalesund. Fearnley, “ 12. Toronto. Kingston. “ 13. Toronto. Kingston. “ 15. Senftenberg. Brorsen. Heis. “ 17. Peckeloh. Weber. Heis. “ 22. Toronto. Kingston. «“ 23. Aalesund. Fearnley. «“ 25. Aalesund. Fearnley. * « 29. Toronto. Kingston. * « 29. Aalesund. Fearnley. * “ 30. Stockholm, Haparanda. Ballot, Heis. * “ 30. Skudesnes. Fearnley. Nov. 9. Christiansund. Fearnley. « 1. Isle Jesus. Smallwood. “ 17. Skudesnes. Fearnley. “ 18. Aalesund. Fearnley. “ 20. Aalesund. Fearnley. “ 29. Peckeloh. Weber. Heis. Dec. 2. Aalesund. Fearnley. « 4, Isle Jesus. Smallwood. “ 5. Aalesund. Fearnley. “9. Skudesnes. Fearnley. “ 12. Isle Jesus. Smallwood. . Queenstown, Greenwich, Penzance, Rome, “ 14. Munich, Montpellier, Cracow, Moscow, “ 14, St. Petersburg, Leipsic. Ballot. “ 14. Netherlands. Ballot. “ 14. Marseilles, Berlin, Peckeloh. Heis. “14. Sandésund. Fearnley. “ 14. Parenzo. Polesino. ’ “ 15. Aalesund. Fearnley. “ 15. Netherlands. Ballot. “ 24. Skudesnes. Fearnley. « 26. Aalesund. Fearnley. 1863. $ Jan. 8. Christiansund. Mohn? “ 10. Christiania. Fearnley, “ 12. Christiansund. Mohn. « 12. Arensburg, Insel Oesel. Heis. Sass. “ 16. Toronto. Kingston. “ 18. Christiania. Fearnley. «“ 24. Toronto. Kingston. Bogoslowski. « 24. Skudesnes. Fearnley. * « 25. Toronto. Kingston. 1 Nederlandsch Meteorologisch Jaarboek, 1863, pp. 302, 319. * Meteorologiske Iagttagelser i det Sydlige Norge, p. 2. * * * * * * * * « * 21. 23. 24. . Toronto. . Christiania. . Toronto. . Toronto. . Insel Oesel. . Insel Oesel. Sass. . Insel Oesel. . Cambridge. . Insel Oesel. . Toronto. . Toronto. . Toronto. . Haparanda, Stockholm. Ballot. . Stockholm. Heis.? . Toronto, Stockholm? Heis. . Toronto.. Kingston. . Insel Oesel. . Netherlands. . Cracow. . Toronto. . Toronto. . Toronto. . Toronto. . Netherlands. . Stockholm, Netherlands. . Sandésund. Fearnley. . Skudesnes. . Berlin. . Aalesund. Fearnley. . Toronto. . Toronto. Kingston. Haparanda. Heis. . Netherlands. . Toronto. Kingston. Liidingen. Ballot. . St. Petersburg. Kupfter.+ . Aalesund. Fearnley. Skudesnes. . Haparanda. . Sandésund, Fearnley. . Toronto. Kingston. Skudesnes. Fearnley. March 4. 12. 18. 20. Ballot. Heis. Fearnley. Heis. Kingston. Ballot. Ballot. Stockholm. Heis. Sitka. Kupffer. Toronto. Kingston, Peckeloh. Weber. Toronto. Kingston. Mandal. Fearnley. Peckeloh. Weber. Stockholm. Ballot. Heis. Stockholm? Heis. Kingston. Fearnley. Kingston. Kingston. Sass. Heis. Heis. Heis. Sass. Heis. Bond. Lovering. Sass. Heis. Kingston. Kingston. Kingston. Peckeloh. Weber. Heis. Sass. Heis. Ballot. a Heis. Kingston. Kingston. Kingston. Kingston. Ballot. Toronto. Kingston. 1 Annales de l’Observ. Physique Centrale de Russie, 1863, pp. 32 and 307. 2 Wochenschrift fiir Astronomie etc., Neue Folge, Jahrgang VIL. 9. * * K * “ . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Sitka. . Toronto. . Toronto. Kingston. Munster. Heis. . Dorpat. . Toronto. . St. Petersburg. Kupffer. Dorpat. . Toronto. . Stockholm. Ballot. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Aalesund. Fearnley. . Eukiill, Insel Oesel. . Peckeloh. Weber. . Toronto. Kingston. Hukiill. Sass. Heis. . Aalesund. . Dorpat, Peckeloh. . Aalesund. Fearnley. . Toronto. . Munster. . Toronto. . Aalesund, Fearnley. . Toronto. . Christiania. . Skudesnes. . Christiania. . Munster, . Peckeloh. Weber. . Athens. . Insel Oesel. . Aalesund. . St. Petersburg. Kupffer. . Insel Oesel. . Munster, Peckeloh. . Stockholm. . Insel Oesel. . Christiania? Ballot.? . Christiania. ON THE PERIODICITY OF THE AURORA BOREALIS. Kingston. Kingston. Kingston. Kingston. Kingston. Kingston. Kingston. 6 Kingston. Kupffer. Kingston. Ballot. Kingston. ‘ Ballot. Kingston. Sitka. Kupffer. Kingston. Kingston. Kingston. Kingston. Kingston. Kingston. Skudesnes. Sass. Heis. Heis. Fearnley. Skudesnes. Weber. Heis. Kingston. Heis. Kingston. Kingston. Fearnley. Fearnley. Fearnley. Heis. Utrecht. Ballot. Lichtenberg. Heis. Schmidt. Heis. Sass. Heis. Fearnley. Heis. Weber. Heis. Aalesund. Fearnley. Stockholm. Heis. Sass. Heis. Sass. Fearnley. 1 Nederlandsch Meteorologisch Jaarboek, 1864, pp. 276, 300. VOL. X. 38 297 Dec. 10. Athens. Schmidt. JnseZ Oesel. Sass. Heis. iil; 12. 12. 28. 29. March 5. (73 “ “ “ “ 29. . Insel Oesel. . Peckeloh. . Peckeloh. . Aalesund. . Aalesund. . Christiania. . Peckeloh. . Peckeloh. . Christiania. . Toronto . Christiania, Skudesnes. . Toronto. . Toronto. 10. 10. te . Aalesund, Christiania. . Munster. . Christiania. . Christiania. Fearnley. Toronto, Kingston. . Toronto. . Sitka. Kiimtz. 7. Toronto. . Christiania. “Fearnley. Munster. Heis. . Peckeloh. Weber. Christiania. Fearnley. Athens. Schmidt. Christiania. Fearnley. [ Heis. Aalesund. Fearnley. 1864. Sass. Weber. Weber. Fearnley. Fearnley. Fearnley.? Weber. Heis. Weber. Heis. Fearnley. Kingston. Heis. Heis. Heis. Fearnley. Kingston. Kingston. Toronto. Kingston. Christiania. Fearnley. Aalesund. Fearnley. Aalesund. Fearnley. Christiania, Fearnley. Aalesund, Christiania. Fearnley. . Toronto. Kingston. Aalesund. Fearnley. . Peckeloh. Weber. - Toronto. . Lichtenberg. Heis. Aalesund. Fearnley. . Naugard. Klopsch. Lichtenberg. Heis. . Peckeloh. . Aalesund. Fearnley. Munster. Heis. . Hanover, - Insel Oesel. . Aalesund, Fearnley. . Aalesund, Skudesnes. . Christiania. . Christiania. . Sitka. Heis. Kingston. Weber. Heis. Heis Sass. Heis. Fearnley. Fearnley. Fearnley. Kimtz. Christiania. Fearnley. Fearnley. Heis. Fearnley. Kingston, Kingston. Naugard. Heis. Toronto. Kingston. 1 Meteorologiske Iagttagelser paa Christiania Observatorium. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Lisbon. . Toronto. . Toronto. . Toronto. . Toronto. . Kephissia. . Kephissia. . Lichtenberg. Bornitz. . Kephissia. . Kephissia. . Toronto.. Kingston. . Toronto. . Toronto. . Toronto. . Toronto. . Toronto. . Nairn, Scotland. France. . Peckeloh? Weber. . Peckeloh. Weber. . Toronto. . Toronto. . Toronto. . Toronto. . Aardenburg, Neth. Roos. . Peckeloh. Weber. . Christiania. . Christiania. Fearnley. Munster. Heis. . Haparanda, Peckeloh. . Stockholm. Heis. Christiania. Fearnley. . Toronto. . Christiania. . Stockholm, Haparanda. . Christiania. . Lichtenberg. Heis. . Toronto. Kingston. Aalesund. Fearnley. ON THE PERIODICITY OF THE AURORA BOREALIS. Kingston. Kingston. Christiania. Fearnley. Kingston. Kingston. Kingston. Kingston. Kingston. Heis. Kingston. Kingston. Kingston. Kingston. Schmidt. Schmidt. Heis. Heis. Heis. Heis.¢ Heis. Schmidt. Schmidt. Kingston. Kingston. Kingston. Kingston. Christiania. Fearnley. Kingston. Naugard. Klopsch. Heis. Arona? Heis. Heis. Sitka. Kiamtz. Kingston. Kingston. Kingston. Kingston. Ballot. Heis. : Fearnley. Weber. Heis. Kingston. Fearnley. Heis. Fearnley. Peckeloh. Weber. Heis. . Valencia, Ireland. Heis. . Insel Oesel. . Insel Oesel. . Insel Oesel. . Aalesund. Fearnley. . Aalesund. Fearnley. . Stockholm. Heis. Sass. Sass. Sass. Lichtenberg. Heis. Paris. Heis. Heis. Oct. 29. “ Noy. Jan. 29. 3. 6. 19. . Peckeloh. Weber. . diilich. Heis. . Stockholm. Ballot. . Peckeloh. . Hérnosaud. Ballot. . Lichtenberg. Bornitz. . Christiania. . Lichtenberg, Hérnosaud. FHeis. . Catherinebourg. Kéamtz. . Peckeloh. Weber. . Stockholm. Ballot. . Frankenthal» Munster, Stockholm. Heis. 4. Hernosand, Haparanda. . Lichtenberg. . Lichtenberg. . Lichtenberg. . Stockholm. Ballot. . Christiania. . Stockholm. Ballot. . Rome. . Stockholm. Ballot. . Peckeloh. . Montreal. . Toronto. . Lichtenberg. Ballot. St. Petersburg. Kiémtz. Insel Oesel. Sass. Stockholm. Heis. Christiania. Fearnley. Insel Oesel. Sass. Heis. Toronto. Kingston. Heis. Aalesund. Fearnley. Heis.4 Lichtenberg. Heis. Heis. Heis. Weber. Fearnley. Munster. Heis. Heis.. Ballot. Heis. Heis. Heis. Heis. Bornitz. Bornitz. Bornitz. 1865. Heis. Fearnley. Heis. Heis. Heis. Weber. Heis. Smallwood. Kingston.? Ballot. Peckeloh. THeis.® “ 17. Munster. Heis. Marseilles. Ballot. “ 19. Toronto. Kingston. “ 24, Munster. Heis. “ 24. Hernosand, Marseilles. Ballot. “ 25. Leeuwarden, Netherlands. Ballot. “« 2%. Paris. Ballot. Heis. “ 28. Mandal. Fearnley. “28. Aalesund. Fearnley. Skudesnes. “ 28. Haparanda. Ballot. Heis. “ 29. Toronto. Kingston. “ 29. Lichtenberg. eis. Haparanda. Ballot. “ 29. Christiania, Skudesnes. Fearnley, “¢ 30. Lichtenberg. Heis. “ 31. Stockholm. Ballot. Heis. 1 Nederlandsch Meteorol. Jaarboek, i loR aly 2 Monthly Meteorological Register at Toronto, Canada West. 3 Wochenschrift fiir Astronomie etc, Neue Folge, Jahrgang VIUL, 5 &e. Jan. 81. Christiania. Fearnley. Feb. 1. Haparanda. Ballot. Heis. “ 4, Hichiill, Insel Oesel Ballot. « 5, Eichiill, Insel Oesel. Ballot. “« 1%. St. Petersburg, Greenwich. Ballot. Heis, « 4. Munster. Ballot. Heis. “ 16. Insel Oesel. Sass. Heis. Ballot. “ 17. Insel Oesel. Sass. Heis. Ballot. “ 17. Peckeloh, Munster. Ballot. Heis. “ 17. Aalesund. Fearnley. “ 17. Hernosand. Ballot. Heis. “ 17. Cork, Ireland. Stevelly. “ 18. Lichtenberg, Naugard. Heis. “ 18. Insel Oesel. Sass. Heis. Berlin? Ballot. “ 19. Aalesund. Fearnley. «¢ 20. Cambridge. Lovering. Toronto. Kingston. “ 20. Montreal. Smallwood. «20. Skudesnes, Christiania. Fearnley. «« 21. Cambridge. Lovering. Toronto. Kingston. «21. Hernosand, Lichtenberg. Ballot. Heis. “ 21. Insel Oesel. Sass. Peckeloh. Ballot. Heis. «21. Aalesund. Fearnley. Skudesnes. “« 21. Christiania. Fearnley. «22. Toronto. Kingston. «« 22. Lichtenberg. Ballot. Heis. “ 22. Hernosand, Berlin. Ballot. “ 22. Christiania. Fearnley. « 22. Insel Oesel. Sass. Heis. «23. Toronto. Kingston. « 23. Lichtenberg. Ballot. Heis. « 26. Hernosand. Ballot. Heis. «“ 27. Lichtenberg. Heis. Berlin. Ballot. March 7. Gorcy bei Metz. Ballot. Heis. “ 15. Toronto. Kingston. “ 16. Christiania. Fearnley. “ 17. Hernosand. Ballot. Heis. “ 17. Stockholm, St. Petersburg. Heis. “ 17. Christiania. Fearnley. “ 18. Peckeloh, Bamberg. Ballot. Heis. “ 19. Lichtenberg. Ballot. Heis. “« 20. Toronto. Kingston. “ 20. Peckeloh. Ballot. Naugard. Heis. “ 20. Lichtenberg, Munster. Ballot. Heis. “« 20. Netherlands, Stockholm. Ballot. “20. Skudesnes, Christiania. Fearnley. « 21, Lichtenberg. Ballot. Heis. “21. Hernosand. Heis. Bamberg. Ballot, «22. Lichtenberg, Bamberg. Ballot. Heis. ON THE PERIODICITY OF THE AURORA BOREALIS. 1 The auroras of Feb. 4 and 5 are probably the same as those of Feb. 16 and 17 expressed in old style. Same as Lukiill. March 23. Lichtenberg. Ballot. 25. 27. 27. 27. 28. 29. 29. 29. 30. 30. 13. 14. 15. 16. 16. 16. ilfig 18. il), 13. 16. ils) 25. 26. 10. 15. 16. ie 20. 21. . Toronto. - Toronto. . Cambridge. . Toronto. Kingston. Cambridge. Lovering. . Toronto. . Toronto. . Toronto. . Toronto. Kingston, Peckeloh. Ballot. Heis, . North Conway, N. H. Lovering. . Toronto. . North Conway, N. H, Lovering. . Toronto, Kingston. NewHaven. A.C.T.} . Munster, Peckeloh. No ST ad bo bw SO N ip iB oo DS bo bo bd = . Christiania. . Toronto. . North Conway, N. H. Lovering. 299 Heis. Christiania. Fearnley. Hernosand, Haparanda. Stockholm. Ballot. Christiania. Fearnley. Cambridge. Lovering. St. Petersburg. Ballot: Stockholm, Haparanda. Christiania. Fearnley. Toronto. Kingston, Christiania. Fearnley. Christiania. Fearnley. Christiania. Fearnley. Toronto. Kingston. Toronto. Kingston. Peckeloh, Munster. Ballot. Christiania. Fearnley. Toronto. Kingston. Toronto. Kingston. Stockholm. Ballot. Toronto. Kingston. Toronto. Kingston. Toronto. Kingston. Toronto. Kingston, Toronto. Kingston. Toronto. Kingston. Toronto. Kingston. Toronto. Kingston. Athens. Schmidt. Toronto, Kingston. Toronto. Kingston. Kingston. Kingston. Lovering. Ballot. Heis . Heis. Ballot. Heis. Heis. Heis. Heis. Kingston, Kingston, Kingston. Kingston. Ballot. Magdeburg. Ballot. Heis. Fearnley. Kingston. Heis. Toronto. Kingston. Stockholm. Ballot, 1 Amer. Journ. Sci., Second Series, XL. 284. 20. 22. 11. ON THE PERIODICITY OF THE AURORA BOREALIS. North Conway, N. H. Lovering. . Toronto. Kingston. Peckeloh. Ballot. Heis. . Toronto. Kingston. . North Conway, N. H. Loverizg. . Toronto. Kingston. . Leeuwarden, Netherlands. Ballot. . North Conway, N. H. Lovering. . Munster. Heis. Palermo? Ballot. . Papenburg. Heis. Christiania. Fearnley. Toronto. Kingston. . Haparanda, Stockholm. Ballot. . Stockholm. Ballot. . Toronto. Kingston. Cambridge. Lovering. . Christiania. Fearnley. . Cambridge. Lovering. Papenburg. Heis. . Munster, Peckeloh, Palermo? Ballot. Heis. . Brouwershavn, Netherlands. Ballot. . Christiania. Fearnley. Toronto. Kingston. . Cambridge. Lovering. Toronto. Kingston. . Cambridge. Lovering. Toronto. Kingston. . Cambridge. Lovering. Toronto. Kingston. . Peckeloh. Ballot. Heis. [ley. . Cambridge. Lovering. Christiania. Fearh- . Toronto. Kingston. . Toronto. Kingston . Peckeloh. Ballot. Heis. . Christiania. Fearnley. . Toronto. Kingston. . Papenburg. Ballot. Heis. ; . Christiania. Fearnley. . Stockholm, Haparanda. Ballot. [ley. . Cambridge. Lovering. Christiania. Fearn- . Toronto. Kingston. . Nairn, Haparanda. Ballot. . Toronto. Kingston. . Toronto. Kingston. Stockholm. Ballot. . Christiania. Fearnley. . Toronto. Kingston. . Cambridge. Lovering. 2, Insel Oesel. Sass. Ballot. Heis. . Peckeloh. Ballot. Heis. . Christiania. Fearnley. . Peckeloh. Ballot. Heis. . Toronto. Kingston. . Christiania. Fearnley. . Toronto. Kingston. . Toronto. Kingston, . Toronte. Kingston. Oct. 26. Christiania, Sandésund. Fearnley. “ 27. Hichiill, Insel Oesel. Ballot. “28. Peckeloh. Ballot. Heis. « 31. Toronto. Kingston. “ 31. Peckeloh. Ballot. Heis. Nov. 7. Hernosand. Ballot. Skudesnes. Fearnley. “ 8. Haparanda, Vendome. Ballot. “« 9. Papenburg. Ballot. Heis. “« 9. Christiania, Fearnley. “ 11. Christiania. Fearnley. “ 14. Aalesund, Christiania. Fearnley. “ 14. Skudesnes, Sandésund. Fearnley. “ 14, Peckeloh, Munster. Ballot. Heis. “ 14. Palermo ?+, Stockholm. Ballot. “ 14. Papenburg. Heis. “ 15. ZLoronto. Kingston. “ 28. Haparanda. Ballot. Dec. 13. Stockholm, Hernosand. Ballot.? “ 14. Christiania. Fearnley. “ 15. Munich.. Ballot. “ 20. Christiania. Fearnley. 1866. Jan. 2. Toronto. Kingston. “ 8. Toronto. Kingston. Cambridge. Lovering. “« 8. Aalesund. Fearnley. «10. Christiania. Fearnley. “ 11. Christiania. Fearnley. “ 16. Cambridge. Lovering. “ 20. Toronto. Kingston. Christiania. Fearnley. “ 27. Cambridge. Lovering. Feb. 3. Christiania. Fearnley. 5. Christiania. Fearnley. 7. Aalesund. Fearnley. “7. Bywell, North Shields. Wheeler.* 8. Aalesund. Fearnley. “ 12. Toronto. Kingston. North Shields. Wheeler. “ 13. North Shields. Wheeler. “ 13. Christiania. Fearnley. “ 14. Ancona, Naples, Haparanda. Ballot. “ 16. Toronto. Kingston. Cambridge. Lovering. “ 17. Aalesund. Fearnley. “ 20. Toronto. Kingston. «“ 25. Stockholm. Ballot. 13 mes te) lr We ee a ee | Wott | 4 2 Z| 0 0 a6 2 7 6 5 rege: LXI. AURORAS OBSERVED AT CHRISTIANIA, NORWAY, ARRANGED BY YEARS AND MONTHS.* Year. Jan. Feb. March. | April. May. June. July. Aug. Sept. Oct. Noy. Dec. Total. 1853 1 3 2 2 3 8 2 3 B 26 | 1854 2 9 8 9 é 6 3 1 : 38 | 1855 2 6 4 4 ; 2 4 3 é 22 | 1856 1 1 3 1 3 5 3 2 5 24 | 1857 2 : 2 : 2 5 il 4 3 17 1858 5 "i 3 5 2 4 8 3 2 39 1859 3 4 7 7 1 71 iG 4 3 46 || | 1860 2 3 6 6 4 6 3 1 3 34 1861 2 3 4 6 : : 3 3 4 4 29 |, 1862 1 3 4 1 : 3 is Te 1 4 31 | 1863 3 9 4 5 ; if 1 5 5 3 36 | 1864 2 3 3 5 1 1 1 4 il 1 22 || 1865 3 3 7 3 i 4 4 4 3 2 33 | 1866 3 3 4 2 2 ; 5 a 1 27 | Total 30 57 58 56 it 0 0 26 59 62 42 33 424 1837-52] 46 61 75 60 |- 0 1 31 69 61 52 53 512 || Total (Go| 18 | Les aH 4 0 1 Fe MISS || 12S 94 86 936 | LXI. AURORAS OBSERVED AT ABO} AND HELSINGFORS, ARRANGED BY YEARS AND MONTHS. Year. Jan. Feb. March. | April. May. June.| July. Aug. Sept. Oct. Nov. Dee. Total. | 1748 3 : é : ; ; ; ; : i F 2 2 |i || 1749 : 2 E gy 2 ; : 1 1 : 6 \| 1750 il : 4 ; A 3 3 A tl , 12 1751 : 2 ; \ 1 dl 1 : ; 1 6 | 1752 2 1 1 1 ' 3 : ; ip 3 1 16 \| 1753 i 1 1 : 4 1 ; 1 9 | 1754 : 1 1 i f 2 4 if : 10 | 1755 at : ‘ ; , : ; : 1 2 || 1757 : ; : il i : ; : ‘ i || 1758 : 1 : ; : : 3 2 1 2 6 || 1759 3 2 il 2 ; ; Bul : 4 13 || | 1760 2 3 ; 3 : 2 1 ' 11 || | 1761 1 2 2 { 1 1 : 3 2 2 1 15 | 1762 2 : 2 2 fl : 2 3 1 1 ; 14 | 1763 A , 2 1 ; 2 1 4 , it 11 | 1764 : 3 4 ; ; 2 ; : ‘ 9 1765 2 ; ; 1 ; : 1 2 6 || 1766 1 ; il ; ; 2 , 2 Gani | 1767 i : i : 1 2 i ; 4 || 1868 2 if : ei 2 : 1 il T | || 1769 1 i 1 : : : d ; 2 4 2 ad ie a | | 1770 i iL : : : ; : 2 wy 1 6 * Continued from page 184. + This table contains the auroras observed at Abo, from 1748 to 1828; and at Helsingfors, from 1829 to 1843. See Memoir by G. G. Hallstrém in Acta Soe. Sci. Fennice, IIT. 306. 304 ON THE PERIODICITY OF THE AURORA BOREALIS. ABO AND HELSINGFORS, (Continued.) Year. Feb. | March. ( April. May. June.; July.| Aug. Sept. Oct. Noy. |_ Total. 1771 1 1 1 5 A il 4 1 2 12 1772 4 3 1 3 1 1 5 4 5 19 1773 4 5 : : ' : : 3 : 15 1774 il 4 oD, , ; 3 2 5 2 21 1775 : 2 : ; , : : ‘ é o 1776 1 2 4 ; 2 ; : : 6 1777 1 2 4 i ; i 1 2 2 | 12 1778 r 2 ; / : 2 A : 1 6 1779 2 3 ; 6 1782 ; A hell 1 3 1783 ; 1 ; ; : ; : : 1 1786 ; 6 1 7 1787 4 4 5 1 4 6 3 3 il eee 1788 2 3 1 3 7 1 1: | 20 1789 2 3 1 3 4 : 3 3 19 1790 3 6 2 5 9 1 2 | 22 1791 1 5 2 1 | £6 1792 6 2 3 ; : 1 ‘ 1 15 1793 21 3 a |e 1 7 1798 1 ; f : i 1801 ; syitae 9 ; 2 1802 : P 2 ; : 1 ; 5 1803 ag ts : 2 1 3 1804 ONE) evoPalt bea ales AN Bt ata 1805 syle 1 1 1817 1 rates 1 A , 2 1821 : ean oe j 1 1823 : a ti 1? 1 1824 : 2 alee ; 1 1 4 1825 1 1 aes: 3 3 1 3 | 12 1826 2 1 ; ; : : al 3 ; 11 1827 Te Tig eee fe 1 3 Be lane a alee 1828 Seeley | aad 8 4 Pe a ici cio fc 2! 1829 Beebe (iecae'|s >: 5 3 6 2 | 27 1830 2 4 il 2 2 5 8 4 3 34 1831 Bao Pagal | lege 1832 ; ; $ I 1 2 2 ! 6 1833 1 4 2 1 8 1834 . 1 1 1 3 1835 1 1 ‘ 3 4. | aa 1836 fame 5 6 ee eat! 1837 2 ; 1 ; 1 : 4 4 1838 1 : : 3 : 1 6 1839 1 hes 1 ; 3 1840 1 1 2 1841 : 1 : , : 1 : 2 1842 i : : ; ; . 1 1843 2 1 : ; ; ; 1 1 ; 6 Total. 87 99 61 9 0 2 28 98 97 74 61 | 682 Dec. IIL. On the Periodicity of the Aurora Borealis. BY JOSEPH LOVERING, HOLLIS PROFESSOR OF MATHEMATICS AND NATURAL PHILOSOPHY IN HARVARD COLLEGE. Arter my first catalogue, comprising nearly ten thousand independent auroras, had been printed, other materials came into my hands which rendered necessary a second catalogue, by which the aggregate of auforas was increased to nearly twelve thousand." Having succeeded in obtaining from Europe a copy of Frobes’s book, entitled Nova et antiqua Luminis atque Aurorae Borealis Spectacula, 1. was able, in this second catalogue, to give the places as well as the dates of most of the appearances which Mairan had quoted from this work. Also, by the kindness of Professor Arge- lander, I received a copy, in advance, of his Verzeichniss von Nordlichtern ete., Abdruck aus den Abhandlungen der Finnischen Societtit ete., containing observations of the aurora made at Abo, Wasa, and Helsingfors, between 1823 and 1837. Professor G. T. Kingston has supplied me with the latest observations made at Toronto, and Professor “Charles Smallwood with others made at the Isle Jesus, in Canada. Mr. Charles A. Schott has obtained for me, from the original records in possession of the Smithsonian Institution, the dates of one hundred and eight auroras observed, between the years 1807 and 1859, by the late Professor Parker Cleaveland, at Brunswick, Maine. General Lefroy, formerly Director of the Magnetic Observatory in Toronto, Canada, has placed at my disposal his large accumulation of observations on the aurora, collected in British America, particularly during the years 1848-1853. Also, Professor Joseph Henry, Secretary of the Smithsonian Institution, has given me free access to the unpublished records of meteorology, made, for a short period, in various parts of the United States, under the auspices of this Institution, and in accordance with the comprehensive plan of its Secretary. I have availed myself of the opportunity, afforded by a recent visit to Holland, to search for the: manuscript records of meteorology kept by Musschenbroek at Utrecht and Leyden. In this attempt I was heartily seconded by M. le Directeur de l'Institut Royal Météorologique des * Those auroras marked by a star, in the second catalogue, are also contained in the first catalogue. VoL. X. 39 306 MEMOIRS OF THE AMERICAN ACADEMY. Pays-Bas, Buys Ballot. After I had found these manuscripts in the library of the University of Leyden, every facility for consulting them was kindly granted by the librarian, Dr. W. G. Pluygers, and by his assistant in charge of the manuscripts, W.N. du Rieu. From this source I have gathered the observations made in Holland on seven hundred and eighty-four auroras, most of which have never been published before. The observations on the aurora in Holland, in Brunswick, Maine, etc., are printed here as a supplement to my second catalogue of auroras. SUPPLEMENTARY CATALOGUE. I. Observations on the Aurora, made by Musschenbroek, at Utrecht, etc. 1728. Feb. 7+, 9+, 11+, 13+; March 20+, 30+; April 2+, 9+, 12+; Aug. 31+; Sept. 30+; Oct. 2+, 7, 12, 29, 30°; Nov. 2+, 23+. 1729. March 27+, 28; Oct. 21+; Nov. 16+. 1730. Feb. 15+; March 6+; April 13+; Sept. 10+; Nov. 5+, 6. 1731. March 7+; April 3+, 13; May 14+; Oct. 2+, 3+, 7+, 8+, 28+; Nov. 6+, 30+. 1732. Feb. 18+; March 21+, 27+; May 27, 28, 30; Aug. 22+; Sept. 27+; Oct. 22+, 23+; Nov. 10, 12s, als) 20+, 21. 1733. April 18, 19°; May 4, 7, 16+, 17; Sept. 5, 6+; Oct. 10+, 15; Nov. 7+; Dec. 23. 1734. Feb. 3; March 22; April 7+, 8+, 9*; May 1+, 4+, 5+, 6+, 24+, 25+, 26+, 27+, 28+, 29, 30+, 31+; June 1, 2, 4, 5,7, 24; July 5+, 6, 7+; Aug. 3, 7+, 9; Sept. 5, 10, 21+, 25+, 27+, 295; Oct. 1s, 2+, 5+, 6+, 14+; Dec. 19+, 25+. 1735. Jan. 23,26+; Feb. 11, 22+, 23; March 1, 2+, 16, 17, 19, 22+, 23+, 24+, 25+, 26+, 27, 28, 29, 30 (dubia); April 20+ (from 8" to 9"), 22+ (clara: from 11 P. mM. to 1, coruscans), 23+ (clara) ; May 14, 17, 18, 19, 22; June 9, 10, 11, 13, 14; July 2, 3, 8, 10, 17; Oct. 24+; Nov. 10, 11, 14+; Dee. 11, 21. 1736. Jan, 22+, 31 (tranquilla) ; Feb. 2 (placida in nubibus) ; March 3 (exigua), 15+; April 3+ (placida), 5+, 11 (placida), 14+ (placida), 27 ; May 4+ (clara), 5 (exigua), 6 (placida), 11 (placida), 14 (magna, tran- quilla), 15 (placida), 27 (placida) ; June 1, 2 (magna), 23 (magna), 24 (magna), 29 (magna), 30; July 25; Aug. 13+; Sept. 3+, 5: (placida), 9+ (coruscans), 25° (placida), 27+, 28, 29- (magna, placida) ; Oct. 1+ 4+?, 6+ (exigua, placida), 7+ (magna), 10+ (magna, tranquilla), 11, 12, 20+, 25+, 26+ (magna), 27+ (maxima), 28+ (exigua), 29+, 30+ (obscura), 31; Nov. 1 (obscura), 7, 8+ (maxima), 10 (levis), 11, 12, 18+, 20, 21, 24+, 25+, 26; Dee. 6,15, 18+ (magna, coruscans), 29, 30. 1737. Jan. 4, 19+, 29+, 30+, 31+; Feb. 2+, 20, 28+; March 1, 4 (inconstans caelum), 8; May 3; June 4, 5, 17, 18, 23, 24; July 26 (tranquilla) ; Aug. 21+ (magna, coruscans), 22» (magna), 26 (exigua), 27, 28; Sept. 17, 19 (placida) ; Oct. 1+; 17, 18, 30; Nov. 19, 20; Dee. 5+, 15 (caeli rubido), 16+,1 18, 26, 28+. 1738. Jan. 25+ (magna, coruscans), 26; Feb. 8 (exigua), 9, 12+, 18 (magna), 19+ 24, 26 (placida) ; March 1 Die 16° vesperi totum caelum rubicundum et lucidum fuit ab hora 6 ad 11 et ultra; postea, novellis publicis vidi in plurimis Europae locis Auroram Borealem observatam. ON THE PERIODICITY OF THE AURORA BOREALIS. 307 11, 17, 18+. 21+, 22, 23, 26; April 13, 18, 21 (et Australis), 28; May 9, 12 (placida), 13, 15 (magna, placida) ; June 5, 8, 16, 17, 23; July 10, 15 (magna), 16, 21; Aug. 7; Sept. 16 (tranquilla) ; Oct. 6, 12+, 17, 18; Noy. 4 (magna, placida, ab hora 5), 7+; Dee. 31. 1739. Jan. 18; Feb. 1+; March 11+, 12+, 13+, 20, 28, 29 (maxima) ;+ April 5+ (exigua), 14, 15, 19, 29+ (placida sed magna) ; May 1+, 2+, 3, 4+, 5 (magna), 6, 8, 9, 10, 11, 12; June 2+ (magna, coruscans), 5, 23 (tenuis) ; July 6 (placida, magna), 7, 12, 15, 28, 31; Aug. 1, 6, 7, 10, 12+, 13, 28; Sept. 1 (tenuis), 8-, 10, 23+ (magna), 24+ (coruscans), 28+; Oct. 3+ (parva), 9 (magna, placida), 24+ (magna, coruscans), 25+ (magna) ; Noy. 21. 1740. Jan. 30+; March 23+. 1741. Jan. 20+, 21+, 22, 23+ (coruscans, magna) ;? Feb. 3, 6, 16+; March 11+, 12+, 13+, 16+ (magna), 29 (meridionalis) ;* April 9+, 13+, 16+, 30; May 7, 8, 9, 10, 12,15, 18,30; Aug. 10+ (coruscans),*13+, 20+ (magna, coruscans), 22+, 31; Sept. 1, 3, 4, 12 (coruscans), 19+, 20; Oct. 2+ (coruscans), 8+, 13+ (placida), 14+, 15+ (coruscans), 28+; Nov. 2+, 12+, 28. 1742. Jan. 13, 14, 23, 29+; Feb. 12, 13; March 13+, 28; April 2+, 3, 8, 10+, 24, 29, 30; Oct. 27+ (magna) ; Dec. 28. 1743. Jan. 1, 3+, 19; March 19- (magna, corusca), 20+, 24+, 26+, 30; Aug. 9, 12; Sept. 8, 9, 18+; Oct. 7. 1744. April 2+, 5, 13, 17; May 5, 16, 27; July 16, 17. i 1745. Jan. 10; Feb. 4,8; April 18, 19, 28; May 19, 30; Aug. 2. 1746. Jan. 26; Feb. 26+; March 19, 25+ (magna), 26; April 14, 17, 18, 20, 21; May 7, 12 (magna), 16 (magna), 17, 26; July 14, 20, 22; Aug. 20, 21, 25; Oct. 22. 1747. Jan. 6+, 8+, 9*, 10+, 11; Feb. 1, 7+, 16; April 2+ (magna), 3+, 5, 9, 10, 13, 29, 830; May 2; July 18; Aug. 4,8; Sept. 6, 10°, 13, 14, 27+; Oct. 1, 2+, 3, 5, 9°; Nov. 28; Dee. 3+, 17+ (magna), 18+, 22, 27 (magna). 1748. Jan. 6+, 7, 20, 29; Feb. 3+, 27+; March 3, 5; April 24, 26; May 1, 2,12, 21; June 3+; July 17, 22; Aug. 1; Sept. 11+, 23+; Oct. 12; Dec. 16+, 18+, 24+. . 1749. Jan. 10, 18, 23; Feb. 11+; March 6, 7, 11+, 28+; April 22; May 10+; July 8, 9, 11,12; Aug. 15, 20; Sept. 22+; Nov. 16. ; 1750. Jan. 3, 6+ (magna); Feb. 3*4 (magna), 7+, 12, 27+ (magna) ; March 4- (placida), 9+, 11+; April 5, 1 Die 29° per totam noctem coruscavit Aurora Borealis, expansa per universum caelum, aeque in parte australe quam boreale, cum columnis subinde ruberrimis, diu perstantibus, praecipue australibus: illuminabat vehementer terram, veluti luna dividua illuminare solet : atrae interruptae nubes in plaga boreale caeli: super has lux candidior erat. 2 Die 23°, noctu, magna, coruseans Aurora Borealis elabitur in plaga orientali, et extenta usque ad austrum; non vero in septentrionali plaga aliquid lucentis phaenomeni conspectum fuit; quatuor se exequentibus noctibus fulsit Aurora Borealis, sed placida fuit tribus primis noctibus, donec quarta nocte ardere visa fuerit, columnasque jaculari ingentes. 2 Sed die 29°, fuit Aurora meridionalis in plaga solstitii Aestivi orientalis usque ad meridiem. Luna fere erat plena, et fulgebat clare in caelo: hine videri non potuisset nisi fuisset coruscans. Sed locus sub illa prope horizontem clarissima luce micabat. Pars caeli borea lucis hujus omnino expers fuit. “ Mense Februario fulserunt quatuor Aurorae Boreales magnae: praecipue die 3°, quae admodum rubra et coruscans: verum 27° die, hora 94 vespertina, erat insignis, quae totam plagam caeli boream occupabat, quamvis non vibrans colum- nas. Quod singulare in ea, distabat ab aurora tractus longus lucidus, ab horizonte ortive ad occasum extensus, non majori sub latitudine quam arcus caelestis, transiens inter Ursam Majorem et Orionem, ferebatur lente ad austrum, quia spirabat corus, postea hine inde inflectebatur, instar serpentis, mox a vento frangebatur in partes: hora 10} jam erat lumen mutatum, propulsum ad austrum, atque a materie nubis borealis magna copia expulsa ad austrum fuit, adeo ut caelum ab omni parte lumine boreo impleri coeperit : hic tractus cumulabatur in trabem, quae caeli fornicem sustentaret : 308 MEMOIRS OF THE AMERICAN ACADEMY. 8+ (magna), 25, 26, 28 ; May 1+ (coruscans), 2+ (tenuis), 3, 4 (tenuis), 6,7, 8 (tenuis), 22, 23; June 2;* July 26+ (coruscans), 27 (coruscans) ; Aug. 4, 5, 26;? Sept. 2 (aurora australis), 7,9; Dec. 14+, 26. 1751. Jan. 8, 4,24; March 1,2, 9 (magna), 15, 16, 17+, 19, 21, 31; April 2+, 19,21; May 22; Sept. 11, 15 (tenuis), 28; Oct. 19; Dec. 24. ' 1752. Jan. 9» (sparsa, placida); March 2, 7+, 18+, 21, 22; April 3, 7 (tenuis), 14, 17 (magna), 18, 21, 26; May 9, 10, 13, 15, 16; Aug. 7, 10, 12+, 29, 31; Oct. 3+ (coruscans), 5+ (coruscans), 12+, 13+ (magna), 14+; Nov. 10+, 11+, 13, 28°; Dee. 5+. 1753. Jan. 2; April 7, 24,27; May 1, 2, 3, 4, 23; Aug. 27; 31; Sept. 22,27; Nov. 28; Dec. 30, 31. 1754. .Jan. 11, 19, 22, 26, 27, 31; Feb. 14, 15, 19, 21, 23, 24+, 27; March 18+, 21, 24 (magna), 25+ (tenuis) ; April 12, 15, 16, 18, 19, 23, 28; May 8, 9, 16,17; July 23; Aug. 14, 17, 19, 22, 23; Sept. 21, 24; Oct. 12, 16+; Nov. 14; Dec. 14, 18, 19. _ 1755. Jan. 15; April 11, 12, 13, 14,15; May 4, 5, 7,15; July 15; Aug. 15,17; Sept. 29; Oct. 3, 10, 14; Nov. 6, 7,9; Dee. 20, 29. 1756. Jan. 20; Feb.5; March 24; April 1,30; May 4, 7,20; July 17; Aug. 1; Sept. 14,17 ee) 24 (parva), 29+; Oct. 12, 26, 30; Nov. 18, 204 Dee. 1, 24, 25. 1757. Feb. 10, 19, 20, 23; March 10 (pulchra), 11 (magna), 17, 20, 25, 26, 27 (levis), 28; April 14, 18, 21, 23, 30; May 13,15, 16; Aug. 9, 12, 15, 16, 19; Sept. 1, 2, 16+ (coruscans), 18; Nov. 12+, 17. 1758. Jan. 7, 8+, 9 (parva), 10 (coruscans) ; Feb. 2, 12, 13, 14, 25; March 13, 14, 29, 30; April 13; May 2, 9, 10, 11; July 27, 28, 29, 30. Il. Auroras observed at Haarlem.* 1735. March 20+, 23+; April 23+; July 17; Aug. 6, 9, 12, 19, 20+, 21, 23+. III. Observations on the Aurora, made by Professor Parker Cleaveland, at Brunswick, Maine. 1807. Novy. 20 (at 8 o’clock), 28 (faint). 1808. Jan. 30 (bright) ; Feb. 18 (bright), 24, 25; March 19, 23, 25, 26; April 14, 22, 23; June 25. 1814. April 17- (brilliant, from 8" p.m. to midnight. At 8" 30™ an irregular are, about 30° above the horizon, from which brilliant coruscations ascend to the zenith. A spot in the zenith detached and radiating in all directions) ; Sept. 11+ (through most of the night), 12 (less brilliant). 1815. Mareh 8; April 12. 1816. Sept. 24+ (arch and radii). 1817. .Feb. 8 (in evening: vertex 30° high), 27 (in spots) ; Oct. 15 (at 9 o’clock, low arc). 1818. Aug. 4; Sept. 20+ (bright: two extensive streamers), 21, 26+ (bright) ; Oct. 1+, 5, 19, 22. ejus materia erat in marginibus rarissima, in medio densior et fulgentior, nonnunquam cum motu tremulo, verum omnes stellae fixae per lumen spectari potuerunt. 1 Mense Junio, die 2°, Augora Borealis erat toto caelo conspicua, fornix nigra et obscura, ab horizonte non procul caelam nitebat et ardebat in rotundum, praecipue plaga orientalis, septentrionalis, et occidentalis. ? Mense Augusto, die 26°, Aurora Borealis coruscans fuit cum multis columnis ab hora 93 ad 10 nocturnam ; die 2°, hora 83, bolis valde nitens fuit. * These were found recorded in the manuscripts of Musschenbroek. ON THE PERIODICITY OF THE AURORA BOREALIS. : 309 1819. March 28; Sept. 22 (bright from 11" p. a. to 12") ; Oct. 11 (at 11° p. u.), 12+ (very bright from 8" to 11° Pp. m.). 1820. April 3+ (semicircular, from E. to W.). 1821. Nov. 26. 1823. Feb. 6, 7. 1827. Aug. 27+ (bright), 28+ (extremely bright and extensive); Sept. 8+ (bright), 25 (singular, of a red color, extending to the south and around) ; Oct. 6+, 10+, 16+, 18». 1828. Aug. 15 (bright) ; Dec. 27. 1829. Jan. 3+ (bright); Feb. 4 (bright); Sept. 18+, 19+; Dec. 19+ (splendid), 22+ (splendid bow), 28+. 1830. Feb. 18+ (splendid, and an arc), 21; March 4, 29; May 15+ (splendid) ; Aug. 13+ (a light bow), 14; Sept. 16+; Oct. 17+. 1831. March 3+, 8+ (brilliant, and a bow). 1833. July 9; Sept. 5» (are from N. W. to S. E., beautiful), 13+ (arch 30°), 14 (arch 10°). 1835. Nov. 16 (rays brilliant after sunset). . 1836. July 7 (N.E. to S. W.), 15 (N. E. to S. W.). . 1837. Jan. 25+ (splendid, extending from N. W. to S. E. in the form of a rainbow. Stars shot forth. It continued some hours, giving the whole earth a red appearance) ; April 6+ (splendid, in evening). 1838. Feb. 21+ (bright in evening), 28 (in evening) ; Sept. 13+ (arc), 14+ (streamers. Arc from E. to W.), 15+ (streamers), 16+ (some streamers), 20+; Nov. 12+ (very brilliant in E.), 14+ (are) ; Dee. 20+. 1839. Jan. 14+ (very beautiful, from N. W. to S. E.); April 21+; May 10+; Aug. 15 (brilliant, N. W. to E.: in evening), 29+ (beautiful in N.: evening), 31+ (in the evening appeared in N. and N. E. some beautiful auroras) ; Sept. 4+ (most brilliant colors), 5 (brilliant again) ; Oct. 10+ (beautiful), 11+ (beautiful). 1840. Jan. 3+ (brilliant), 4+ (brilliant), 6 (brilliant) ; Feb. 24+, 1848. Oct. 23 (brilliant), 25 (brilliant), 26+, 27+, 28+; Nov. 17+ (brilliant and partly bright red). 1849. Novy. 27+ (splendid, a red appearance). 1857. Sept. 3+. . IV. Observations on the Aurora, made by Lieutenant C. J. B. Riddell and Captain J. H. Lefroy, at Toronto, Canada+ 1840. Jan. 3+, 31+; Feb. 7+, 8, 28+; March 5+, ce 21+, 25+; April 1+, 4+; May 27+, 28?+, 29; Aug. 19s, 21s, 23-, 24+, 25-, 28+; Sept. 2+, 16+, 17, 20, 21+, 25°, 27+; Oct. 19+, 22°, 31°; Nov. 13°; Dec. 20+, 23+, 28. 1841. Jan. 9, 18+, 24+, 25+, 27+; Feb. 11+, 12+, 15+, 23+, 24+; March 11+, 14+; April 13, 18+, 19+, 21+, 26; May 26+; June 15+; July 6+, 14, 15, 19+, 21+, 24+, 28>, 30; Aug. 6, 11, 14, 22, 23; Sept. 12+, 13+, 25+; Oct. 7+, 8+, 9+, 13+, 15+, 24+; Nov. 4, 5+, 8*, 18°; Dec. 14+, 17>. 1842. Jan. 10, 15+, 29; April 10+, 11+, 14+, 15+; June 4,14; July 2?+, 3+, 9+, 11+, 14, 31-; Aug. 5+; Sept. 1, 2+, 13+, 15+, 16+, 28; Dee. 5+. ? 1843. March 5-, 6+; April 5:, 6+; June 30+; July 2+, 7+, 25+, 26; Aug. 3+; Sept. 18+, 20+, 21+, 27+, 29; Oct. 19+; Dec. 11:. . 1844. Jan. 24+, 28+; March 2+, 7+, 9¢; April 16+, 18+; May 7+, 8+, 14+, 22+; June 20°; July 8; Aug. 9», 29°; Sept 14+, 19+, 30?+; Oct. 20+; Nov. 15+, 16+?. ? From the manuscripts of Captain (now General) Lefroy. 310 MEMOIRS OF THE AMERICAN ACADEMY. 1845. Jan. 9+; Feb. 24+; March 12+, 13+; April 13+, 28; June 30+; July 5+, 8+, 24+; Aug. 1+, 2+; Sept. 8+, 7+, 24+, 25s, 26; Oct. 9°, 20°; Nov. 27+. 1846. Jan. 23+; Feb. 25+; March 17+; April 2, 15+, 19°; May 3+, 4+, 11+, 18, 19+, 24, 30+, 31*; July 1, 14, 19, 20+, 24+, 30, 31+; Aug. 12+, 13+, 14+, 16+, 24+, 25+, 26, 28+; Sept. 11+, 12+, 16+, 21+, 22+, 23%, 27°; Oct. 2+, 9+, 11+, 19+, 24+; Nov. 30+; Dec. 23+. 1847. Feb. 22+; March 4+, 18+, 19+, 24, 31; April 3+, 7+, 8°, 19°; May 7-; June 12+, 13; July 9-, 11+, 22; Aug. 4+, 16°, 21+, 22+; Sept. 27+; Oct. 8+, 12+, 14°, 15+, 22+, 23+; Nov. 2+, 3*, 5+, 9+, 22+, 25°, 26°; Dec. 8, 16+, 17+, 19+. ’ 1850. Jan. 9+, 13, 18+, 19+; Feb. 5+, 9+, 11+, 12+; March 4+, 16+, 24+, 31+; April 1+, 5+, 6+, 8+, 9°, 11+, 15s, 16+, 18+; May 7+, 8+, 9+, 12+, 13+; June 30°; July 3+, 9+, 10+, 11+, 15+, 29+; Aug. 1+, 2+, 9+, 10+, 15», 16+, 17+; Sept. 2+, 3*, 7+, 10+, 29+, 30°; Oct. 1s, 2+, 5s, 6+, 13°, 25*, 27+, 28+, 29+, 30°; Nov. 8+, 10+, 29°; Dec. 27+. 1851. Jan. 26; Feb. 5+, 18+, 28°; March 2+, 7+, 11+, 22+, 28+, 29°, 31+; April 3+, 28°; May 4+, 7», 17+; June 5+, 13+, 26+, 27+; July 2+, 14+, 17+, 18+, 26+; Aug. 5+, 20+, 24+, 26+, 29+, 30+, 31+; Sept. 2, 3, 6+, 7+, 12, 15+, 16+, 29+, 30+; Oct. 1+, 2+, 3+, 4+, -18+, 20+, 21+, 22+, 23°, 26°; Nov. 3, 12+,:15+, 17+, 18+, 23+, 24+, 29+, 30+; Dee. 1+, 4+, G+, 12+, 13+, 18+, 19+, 21+, 23+, 25+, 28+, 29. 1852. Jan 13°?, 19+, 21+, 22+, 23+, 24-, 26°; Feb. 1+, 13+, 15+, 16+, 18+, 19+, 20+, 23°; March 10>. V. Observations on the Aurora, made by Professor Charles Smallwood, at St. Martin, Isle Jesus, Canada. 1852. Jan. 19+, 26+; Feb. 15+, 19+, 20+; March 7+, 19+, 20+; May 5+, 6+, 18+; June 11+, 15+, 23; July 5s, 6+, 7+, 10+, 20, 29+; Aug. 5+, 6+, 10+, 11+; Sept. 3°, 4+, 16+, 17+, 18°, 29°; Oct. 6+, 19», 20*; Nov. 11+; Dee. 1+, 29+. 1856.?_ Jan. 27, 31+; Feb. 9, 24, 26; March 3+, 4+, 6+, 8, 23; April 10,23; May 1,5; June 5; July 1, 24; Aug. 17, 22+, 31+; Sept. 1+, 8+, 24, 27; Oct. 4+, 23+, 24, 25, 26; Nov. 5, 20+; Dec. 20, 28+, 29. 1857. Feb. 26+, 28; March 1, 17+; April 15; May 3, 13+; June 4, 24; July 11+; Aug. 26+; Sept. 3-, 10+, 23+, 25, 30; Oct. 23+, 24+; Dec. 4+, 8, 20+. 1858. Jan. 5, 8+, 10+, 13+, 17+; Feb. 17+; March 3+, 12+, 13+, 31+; April 3+, 8, 10°, 1]*, 16; May 7s, 9+ 16; June 11; Aug. 2, 11, 12, 16+, 26, 31+; Sept. 1+, 7+, 10+, 11, 18, 20+, 22+; Oct. 10, 11, 18+, 27+, 28°; Dec. 1s, 11, 24+, 29. VI. Observations on the Aurora, made by Professor Charles Smallwood, at Montreal, Canada. 1862.2 Jan. 2+, 3, 13+, 24+; Feb. 1+, 20+; March 2, 19+, 26+; April 1+, 28; May 2+,-6+, 30°; Aug, 4+, 8, 13+, 18, 19+, 28+, 29°; Sept. 2+, 3+, 9+, 24+, 25+, 26%, 27+, 28>. 1863. Feb. 8+, 9+, 27; March 9; Aug. 25; Oct. 9+; Dec. 30. 1864. April 3, 4+, 24-; May 2,9; June 7-; Aug. 27, 31-; Sept. 7,17; Oct. 19+, 24+. 1865. Jan. 16+, 17+; Sept. 16+, 28+; Oct. 10+. 1866. April 5, 6, 7+, 9, 17+; Sept. 13+; Oct. 3+, 4+; Dec. 10+. 1867. March 6, 10, 16,17; May 31+. 1868. March 22; April 13+; May 11; Sept. 5; Oct. 6, 1869. Feb. 5; June 4; Sept. 5; Oct. 31. 1 Amer. Journ. Sci., N. S., XVI. 78. * From the manuscript records of Professor Smallwood. ON THE PERIODICITY OF THE AURORA BOREALIS. 311 LXII. AURORAS OBSERVED IN HOLLAND, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Noy. Dec. Total 1728 4 2 3 ; 1 1 5 2 18 1729 F 2 5 : : ; 1 1 4 1730 1 1 1 A 0 4 1 F 2 6 1751 ae 1 2 1 : 4 5 5 2 11 1732 1 2 5 3) ; ‘ 1 1 2 5 3 15 1733 : 7 2 4 : : : 2 2 1 1 12 1734 6 1 1 3 12 6 3 3 6 5 5 2 42 1735 2 3 14 3 5 5 5 ; : 1 3 2 43 1756 2 1 2 5 7 6 1 1 Uf 15 12 5 64 1737 5 3 3 : 1 6 1 5 2 £1 2 6 38 1758 2 7 cl 4 4 5 CS alt eat 1 4 2 1 42 1739 1 1 6 5 13 3 6 7 6 4 1 : 51 1740 1 : i 2 5 , f 2 1741 4 3 5 4 8 : 5 6 6 3 ‘ 44 1742 4 2 2 7 3 : : 1 1 17 1743 3 5 9 3 6 2 3 1 é 14 1744 ; : 5 4 3 2 - ; 9 1745 1 2 S 3 2 j il : ; ) 1746 1 1 3 5 5 3 3 : 1 : 22 1747 5 3 : 8 1 il 2 5 5 1 5 36 1748 4 2 2 2 4 1 2 1 2 1 3 24 1749 3 1 4 1 1 “ 4 2 1 ; 1 : 18 1750 2 4 3 5 9 1 2 3 3 0 : 2 34 1751 3 9 3 1 : 3 iL ‘ 1 21 1752 1 5 di 5 5 , 5 4 1 33 1753 1 ‘ : 3 i) , 2 2 : 1 2 16 1754 6 ra 4 “f 4 if 5 2 2 1 3 42 1755 1 : i) 4 il 2 1 3 3 2 22 1756 1 1 1 2 3 1 1 4 3 2 3 22 1757 4 8 5 3 5 4 2 31 1758 4 5 4 1 4 4 22 Total 57 o7 97 100 110 35 46 57 59 79 49 40° | 784 LXIV. AURORAS OBSERVED AT THE HAGUE, ARRANGED BY YEARS AND MONTHS.1 Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Total 1745 : : 1 A : ; - q : 5 : 5 1 1746 : 2 1 1 : : 1 : : 1 2 : 8 1747 2 4 2 : 5 1 3 1 10 1748 | 1 : 4 1 4 10 1749 | 2 : 1 3 1750 1 2 + 1 1 2 1 12 1751 1 3 2 2 1 ; 9 1752 1 1 1 7 3 13 1753 2 1 1 4 1754 1 1 2 4 1755 : 1 2 1 4 1756 ‘ 8 1757 2 1 1 1 1 2 8 1758 10 Total it 10 11 10 2 0 6 6 8 11 4 11 104 1 Observed by Peter Gabry, and found in the manuscripts of Musschenbroek. 312 MEMOIRS OF THE AMERICAN ACADEMY. LXV. AURORAS OBSERVED AT BRUNSWICK, ME., ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Novy. Dec. = lo 2} bo ~ eR bo. . . bo ne ke DO Oren To out me [o2) oo So * BOs bo i bo _ lee) oo ~1 _ i _— [o.2} rss ios) or es lo 2) rs (i) ee FRE DROON NEE NWONN ONH HO OOF tS Oot tS Total di 13 10 8 2 1 3 9 23 19 8 5 Year Jan. Feb. Mar. Apr. May June July Aug. | Sept. Oct. Noy. Dec. 1842 | 4 1 1 1 1 1843 1 2 1 : il 2 = 1844 2 1 - 2 1 1 1845 2 1 1 1 1847 y 1 + 2 4 2 1848 1 2 C - . 1849 : 1 2 1 1850 1 1 1 2 1 2 1852 1 1 2 : : 1 4 1856 2 1 1 5 3 2 1857 , E 1 1 1 1858 3 4 1 1 3 2 1 4 1859 2 1 1 1 : 3 2 1 1860 5 2 5 1 1861 : > 1 1863 1 1 1 1864 2 il Total 3 8 18 11 2 0 i 11 12 10 12 16 ON THE PERIODICITY OF THE AURORA BOREALIS. alte LXVII. AURORAS OBSERVED AT ST. MARTIN, CANADA, ARRANGED BY YEARS AND MONTHS. Feb | Mar. Apr. May June July | Aug Sept. Oct. Noy. Dec. Total 3 3 3 3 3 6 ft 6 3 1 2 36 4 1 Af 4 2 uf 3 6 1 2 3 39 5 6 5 5 2 7 3 8 2 er 3 50 2 5 4 4 ‘ 3 t 2 3 5 4 37 3 5 2 2 1 2 3 4 5) 2 3 3B4 2 2 1 2 2 1 1 5 2 e 3 21 1 4 5 3 1 . 6 7 5 3 A 41 5 7f =6 2 c 2 4 5 4 3 3 41 4 8 4 1 - 3 10 5 4 1 1 42 2 5 6 z 1 3 4 5 aa 2 2 36 1 2 1 2 6 7 1 i 2 26 | 382 48 38 28 12 B4 48 60 34 14 30 403 Feb. Mar. Apr. May June July Aug. Sept. Oct. Noy. Dec. Total > 5 il : 1 : 3 : 2 5 : c 4 - 8 : 1 1 : : 2 3 ‘ : 1 1 ; 1 . 6 5 1 2 2 2 . 1 8 1 1 2 1 1 3 : 9 : : ; 4? 1 ‘ 5? 3 7 3 1 1 2 3 16 3 1 41 2 2 4 2 4 1 : 3 i 19 3 2 3 1 ik 2 2 8 4 1 28 A - é F : 1 1 oa | : : 1 2 : 2 F A 1 : 1 1 1 3 iL 5 5 1 1 3 5 1 7 1 1 : 1 1 i 1 $ 1 1 3 : 1 1 2 2 12 8 24 Jd |) G4 4 11 19 33 5 12 4 20 10 13 13 17 20 28 31 9 10 21 32 46 VOL. X. 40 314 MEMOIRS OF THE AMERICAN ACADEMY. , LXIX. AURORAS OBSERVED IN THE UNITED STATES OF AMERICA, ARRANGED BY YEARS AND MONTHS. x : MAINE. Jan. | Feb Mar. | Apr. May | June | July Aug. Sept Oct. kb 2 4 7 3 3 1 8 3 2) 2 9 4 4 - 1 2 1 PRL f 1 : 5 s : - 3 2 ae RES ll 8 ll ee ee 3 12 6 VERMONT. F 1 2 1 4 4 4 1 3 4 1 2 2 2 4 ; 4 : 1 4 1 4 , 3 3 A i 0 5 4 5 3 Tea a) 6 9 ll MAssACHUSETTS. 1849 % 3 : : 1 2 3 3 1850 : 3 2 1 2 e , 4 1851 3 1 1 : 1 3 : 2X Total 3 1 4 ES || ia 1 4 0 5 i ConNECTICUT. 1849 ? 1 2 1 E | 2 2 1850 1 2 5 3 1 2 1 1 i 3 1851 3 2 ‘ 4 1 | 5 1 1 Total if 4 ie iS 6 CT | es 23 1 | 6 New HaAmpsHIRE. 1849 2 E 1 5 i Ue val: 1850 1 2 1 3 : | oe 1851 1 : 2 il 1 4 3 Total| 0 1 ae 2 2 ay | age | 7 5 New York. 1849 ‘ St here Z E j : : 1850 | 2 4 6 | 4 . 3 A270 oy 2 3 1851 6 2 - il 2 1 ak 4 1 Total 2 10 thee) ieee: Sie | fame 8 5 5? et ee 4 PENNSYLVANIA. 1849 5 4 4 2 AE 2 7 2 1850 5 4 4 8 2 3 4? i 3 5 1851 2 3 9 4 4 : eo Ae Bl 1 Total | 7 7 17 16 8 a eS a ae 11 7 Outro. 1849 4 4 1 1850 1 1 1 é 1 ON THE PERIODICITY OF THE AURORA BOREALIS. 315 LXX. AURORAS OBSERVED IN THE UNITED STATES, ARRANGED BY YEARS AND MONTHS. ILLINOIS. Year Jan. Feb. Mar. Apr. May June July | Aug. Sept. Oct. Noy. Dec. Total S29 as : é 1 é 2 . 2 F : ; be 3 1850 1 1 1 3 2 d - ; F s : 5 1851 H 1 é : , ; : é 3 , 5 ; 4 Total 1 1 1 2 0 4 0 0 3 0 0 0 12 - INDIANA. 1849 , | ‘ 1 1 : ; 2 1851 2 3 . 1 2 3 : 5 Total OR orl Pre 0 0 1 1 0 2 0 0 0 7 MICHIGAN. 1849 4 : a 2 5) F 4 2 3 i B 24 1850 5 1 2 3 3 3 / 12 1851 3 1 A ion 1 ‘ : 3 4 ‘ 12 Total | 3 2 9 5 6 0 Any = |e3 ) 6 1 0 48 Towa. 1850- | 1 1 1851 1 | | 1 | 1 | 3 MINNESOTA. STOR Say |e é és i 2) |= 22a ee ae 1 WISCONSIN. 1849 2 3 . 1 2 4 1 il 1850 3 2 2 2 2 11 1851 il 3 2 . 1 4 3 2 2 1 ‘. 12 Total 1 Sinn eed i) 1 Ten eo) 6 ZT Na) 0 1 34 New JeERSEY. 184 2 1 : : : 3 1850 . é . 2 1 fi 5 5 : 2 | 5 1851 1 : : 3 F ‘ 1 z 1 1 ‘ : 4 Total 1 0 2 2 1 1 1 OF | Srl 0) 0 12 . MARYLAND. 1849 : 2 1 i ; - 3 1 1850 : : 2 , : 3 il 1 1851 : 1 : : : : 1 5 : a 3 Total 0 1 1 0 0 1 OS an 0 0 0 5 WasuiInGTON, D. C. 1849 1 4 1 1851 : ; F 5 7 5 3 . 2 1 2 . 3 Total 07 OR real 0 0 Ove 2) 0 2 1 0 0 4 DELAWARE. 1849 whatea |. . <4 ee ie eee ee TSN ie dl & VIRGINIA. 1849 | - , ete 3 : z | , 1 | | 1 1851 2 2 Norta Caro.ina. 1851 o |) Se ae z ee ee eee eels see ae ak Soutn CAROLINA. . 1851 o. ta ae ae ae a ee | is |; oes | eee | eee en | "TENNESSEE. iil || ee | a a ae a eae ee a a ce ee iB 316 MEMOIRS OF THE AMERICAN ACADEMY. LXXI. AURORAS OBSERVED IN BRITISH AMERICA, ARRANGED BY YEARS AND MONTHS. HALIFAX. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. 1848 A F il i > , 5 ‘ 1849 1 5 2 8? 4 1? 3 1 3 3 1850 1 4 6 4 3 5 8 9 8 8 2 1851 3 5 6 7 é : 5 1852 4 9 8 4 4 2 9 2 4 1 1 Total 9 23 23 23 11 8 20 aaa 12 3 Monrreat.} 1848 1 10 6 9 1 2 1 5 1 2 2 1849 1 3 1 5 1 2 2 1 5 4 1 1850 1 3 4 5 1 2 9 'N) 4 4 1851 4 4 1 4 2 1 1 i) 2 1852 2 4 ‘ 1 5 3 of 2 3 3 1862 4 2 3 2 3 7 8 ‘ 1863 3 ] : ; 1 3 1 1864 3 2 1 2 2 2 1865 24 ; 2 1 1866 5 1 2 1867 4 1 1868 F ‘ 1 1 1 3 1 1 1869 ‘ 1 : 1 1 KINGSTON. 1850 4 1 3 Gy 3 5 5 1 1851 1 5 5 1 : 2 2 5 2 1852 2 6 4 4 5 6 7 ; a sere 3 Total 2 ies (Pa) 7 6 6 15 5 12 11 1 QUEBEC. 1848-51 6 25 14 24 7 10 13 | 10 19 21 13 1852 1 if 1 2 5 plane it 8 5 5 Total 7. Bet 7 26 PT Pas 9 | a 7 26 | 18 ALBION MINEs. 1849 : 4 3 . 2 3 2 | 1 1850 1 2 4 3 4 : 4 1 6 1 1 1851] 5 2 3 1 : é 2 3 3 2 | Total| 6 | 8 10 4 0 6. | OR me 5 2 MiIcHIPICOTON. 1849 ; : 5 4 1850 2) 4 3 7 1 6 4 2 1 2 2 1851 2 6 6 9 5 2 5 3 Moose Factory. 1850 : 3 z , Z 6 18 17 12 13 9 1851 14 12 15 20 17 11 17 13 15 12 5 1852 18 12 15 : ‘ 1 The series is imperfect. The auroras for 1848 and 1849 were taken from a printed circular of Captain Lefroy. ON THE PERIODICITY OF THE AURORA BOREALIS. 317 LXXI. AURORAS OBSERVED IN BRITISH AMERICA, ARRANGED BY YEARS AND MONTHS. Fort Simpson. Apr. May June July Aug. Sept. : : 8 nae a | 43 21 Perr’s River. : 6 4 4 3 | 10 Fort GEORGE. | ; Sl) we : t 6 6 : Fort ALBANY. Martin Fatts. | 5 | Es | : | : 2 10 | . } . . Lewis AND PELLY. ye | 2 é ; 1 5 | 9 A F 4 : MATAWAGOMINGEN. : é | 3 6 5 : : Il ars 3 3 4 3 PENETANGUISHENE.! 2 : | 10 4 6 8 z Lake NIpIcon. = E | 2 | 7 : : ATHABASCA. EA eae Fort CONFIDENCE. > ee 4 Fort ENTERPRISE. : : | 10 6 | is | 9 as CUMBERLAND Howse. liegaee ; | Pies | 2 | 15 11 hack i 1 A few auroras were observed in 1848 and 1849. 318 MEMOIRS OF THE AMERICAN ACADEMY. LXXIII. AURORAS OBSERVED AT AALESUND, NORWAY, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Noy. Dec. Total 1861 1 3 6 - ; , 2 4 16 1862 3 4 a - 1 4 2 2 16 1863 ; 2 3 : 4 1 2 9 1864 2 2 6 ile : 3 1 15 1865 1 3 : : 4 2 1 5 1866 1 2 : : 2 ; 5 : 3 4 ; 10 Total 8 16 12 1 0 0 0 0 1 14 11 8 71 Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Total 1859 5 : : 5 i 2 : } 2 1860 1 4 2 c 2 3 1 A 13 1861 3 . 5 5 5 5 1 3 9 1862 1 1 1 : = 3 1 1 ‘ 5 1863 1 2 1 2 - 3 1 d 2 9 1864 5 e : - 5 3 : 3 6 1865 4 4 1 = = 3 1 1 1 1 16 1866 |. 1 1 ; gO 6 1867} 1 ; 1 1 E 3 ; ; 1 a) pac ; 5 Total| 8 a 15 5 0 0 0 5 9 geal ees 12) ) wa 1788-92 | 27 34 50 56 13 0 0 19 44 39 34 25 | 341 Total| 35 41 65 61 13 0 0 24 53 46 37 37 | 412 LXXV. SECOND GENERAL CATALOGUE OF AURORAS, ARRANGED BY YEARS AND MONTHS. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Noy. Dec. Total eee ees | 4s 7) G2. 1 AB. | 46 35'"\| Sop) Gos igs lise. | Soe Sl ayasspe 1816 < : 1 : 5 5 1 1817 : 2 ; : 1 1 e 1 5 1818 1 . 1 1 1 3 5 3 7 1819 é 1 1 1 1 4 c 4 1820 5 : 3 5 5 z 0 1821 6 1 : 7 6 3 2 25 1822 4 1 2 1 1 : 9 18 1823 E 4 : ; 1 : c 5 1824 6 2 3 E é : 1 3 1825 5 5 z 1 ez 1 : 1 5) 1826 2 1 : Fs : : s 1 : 4 1827 S 3 1 1 “ 4 7 2 F 18 1828 1 2 1 3 4 2 4 4 21 1829 ; 4 5 4 4 ° 3 Ze 1 21 1830 3 1 5 1 ; 1 2 4 2 2 21 1851 6 2 2 5 s 1 : 6 é : 16 1832 : 2 1 3 : : 2 2 7 1833 3 2 ; 1 1 5 1 3 é 11 1854 5 5 : 5 5 3 0 1835 1 2 1 2 3 9 ON. THE PERIODICITY OF THE AURORA BOKEALIS. 319 SECOND GENERAL CATALOGUE OF AURORAS. Continued. Year Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Noy. Dec. Total TS26s\r2e< 1 1 ia ; : 2 : 3 3 1 ll 1837 ; 2 : : 1 ‘ 1 : : 1 . 5 1838 e 1 . a ; 1 F 2 1839 F : 1 2 2 : 5 1840 1 1 1 1 1 1 2 8 1841 1 1 : 2 1842 c 1 1 1843 1 A 1 2 1844 : 1 1 1 : 3 1845 : 3 1 : 4 1846 : 1 2 : 1 4 1847 1 5 5 : i : : o) 1848 1 2 : 1 2 1 1 : 8 1849 : 1 : 7 4 3 5 4 1 4 1 30 1850 A 6 6 9 7 16 15 10 4 7 21 9 114 1851 14 10 21 21 15 16 16 15 12 15 21 19 193 1852 if 17 12 11 10 10 14 16 6 16 ey 12 158 1853 15 20 12 17 5 5) 3 3 3 9 4 Hi) 101 1854 : 6 6 6 3 1 2 3 1 4 1 : 30 1855 3 Hi) 2 4 1 4 2 4 2 3 3 a 34 1856 - 6 7 3 2 1 4 3 6 3 4 6 43 1857 : 1 3 1 3 1 oy) 1 6 2 1 2 26 1858 5 1 ‘ 4 6 5 4 4 6 6 4 2 47 1859 3 4 11 8 8 3 9) 3 7 oy) 5 3 65 1860 6 3 5 7 7 2 12 7 2 1. 2 4 64 1861 5 5 2 13 5) 2 4 5) 9 a 6 12 75 1862 6 5 @ 7 8 3 7 8 6 8 6 9 80 1863 7 5 9 a 2 5 6 5) a 5) 8 7 73 1864 9 8 10 10 3 5 3 9 vu 13 4 11 92 1865 15 14 15 7 3) 7 8 14 12 16 7 4| 124 1866 7 a 10 5 7 2 3 5 4 12 12 3 77 1867 : ; 1 2 5 1 4 3) 18 1868 : : 2 3 1 6 2d Cat.| 144 | 167 195 163 141 122 134 | 1384 | 149 184 | 158 | 157 | 1848 Suppl) 58) 1452) |, 78 | 92). |. 75 18 || 47. |. 74 | 55 A So Sen ereas Total | 202 | 219 268 | 255 216 140 181 208 | 204 | 2351 190 183 | 2497 Ist Cat.| 932 950 |1168 | 915 497 | 315 | 363 630 |1015 |1110 | 964 | 9077| 9885? Total |1134 {1169 |1436 |1170 | 713 | 455 | 544 | 838 |1219 |1341 1154 {1090 |12382 1 These supplementary numbers are obtained from the auroras printed on pages 306 — 310. ? Erroneously printed on page 200. 320 MEMOIRS OF THE AMERICAN ACADEMY. By the help of my second catalogue, and the supplement, the yearly march in the number of auroras observed, from month to month, can be accurately determined for Sitka, Toronto, Quebec, Newfoundland, ete., for which the materials in the first cata- logue were insufficient. But the large addition of more than two thousand to the aggregate number of auroras will throw little ight on our inquiry into the secular periodicity of the aurora, inasmuch as they belong, for the most part, to a short period of years, and furnish no long series of observations at any single place. And even those subordinate fluctuations, which some suppose to move synchronously with the disturbances on the sun’s surface, require for their elucidation continuous observations, at the same place, for many decades. If sufficient evidence exists for believing that the disturbances in the sun’s atmos- phere, which reveal the solar spots, are associated im time with those other disturb- ances, whatever they may be, which result in displays of the aurora, this coincidence between the two classes of phenomena, pointing to a mutual dependence or to a common origin, will guide speculation, if it do not even furnish the key for the unlocking of some of the great mysteries of the physical world. The testimony in favor of such a coincidence must, therefore, be subjected to a rigid examination. A glance at the curves which represent the periodicity of these phenomena will satisfy any one that the march of the changes in spot-frequency is far more regular, both in degree and in time, than that which is furnished by the aurora. : I shall now examine separately each of the twenty-eight maxima and minima of the solar spot curve between 1700 and 1860. 1. First comes a maximum in 1708. A decided maximum of the aurora is found in 1707. If the secular period of the aurora is taken at fifty-seven years, a secular minimum would have occurred about the year 1701. This may account for the postponement of the subordinate maximum by two years. Six auroras were observed in Great Britain in 1709, a few before, but none afterwards for six years. 2. The spot-minimum of 1712 is accompanied by an aurora-‘minimum. I attach less weight, in general, to the agreement of minima, because the evidence is negative. The number of observed auroras is subject to violent transitions, from year to year, not witnessed in the number of solar spots. As few auroras were observed in 1714 and 1715 as in 1712. Nevertheless the year 1712 is the central period of half a dozen years during which auroras were infrequent. No auroras were recorded in Germany in 1712, 1713, 1714, and 1715, although four or five in all were seen during the four preceding years, and more afterwards. 5. Next comes the spot-maximum of 1717. There seems to have been an aurora-maximum in Paris. But an error exists undoubtedly in the record, which has doubled the number ON THE PERIODICITY OF THE AURORA BOREALIS. 321 of observations. Either the year 1716 or 1719 is the more probable time. No auroras were observed in Sweden in 1717 or 1719, and only one in 1716 and 1720; but nine were observed in 1718. Four auroras were observed in Berlin in 1717; but four were also observed in 1718, 1720, and 1722. In Great Britain, two auroras were seen in 1717, none in 1718, but nine in 1719. Two auroras were seen at Salem in 1719, the first recorded appearances in New England. 4. In 1723 comes another spot-minimum. In Sweden there is a plausible conformity on the part of the aurora, though the mini- mum comes one or two years earlier. In Great Britain no auroras were observed in 1724 ; but more were seen in 1723 than in any previous year since 1719. In Berlin, also, none were seen in 1724, but more were seen in 1725 than at the spot-maximum of 1717. In Germany an aurora mmimum may be conceded to the year 1723, although three more were seen than in 1720, and four more than in the year of spot-minimum, 1717. The twenty-eight auroras observed in that country in 1722 militates strangely against the supposition of an auroral minimum the very next year. The absence of all auroras in America in 1723 proves nothing, as they were equally wanting in 1717 and 1727, both years of spot-maxima. 6. I pass on to the spot-maximum of 1727: A large number of auroras is recorded against this year in Italy. But the force of this agreement is weakened by the fact that almost as many were seen in 1730 and possi- bly more in 1724. In France none are found for 1727, and fifteen for 1724. In Germany only thirteen auroras were seen in 1727, and forty-two in 1730. In Berlin the number of auroras was larger than in 1725, but not so large as in 1730 and 1732. In Great Britain the number of auroras was greater than in the years immediately preceding and following, but exactly the same as in 1723. In Sweden eight auroras were observed, or more than in any other year since 1718, but the number continually increased until it reached fifty-two in 1750. In St. Petersburg eleven auroras were seen in 1727, and thirty-six in 1750, with six and twenty-five for the two intermediate years. The observations at Abo and Cola may be left out of the account, as the series are evidently defective. 6. In 1733 occurs the next spot-minimum. In Italy only one aurora was seen this year and the next, but none in 1729. An extraordinary number of auroras are recorded against the years 1752, 1753, and 1754, although 1733 is the minimum year of the three, in France, which, if not otherwise explained, flatly contradict the Wolf theory. The Wittemberg observations exhibit an unqualified minimum for 1733. The German observations, in general, point to an equally decisive minimum, although it comes a year later. Three times as many auroras were seen in Holland in 1733 as in 1729, but a great increase appears in the following years. In Berlin there is a goqgd maximum in 1752, and nearly one in 1753. In the two VOL. X. 4] 322 MEMOIRS OF THE AMERICAN ACADEMY. following years there are only half as many, and the series itself terminates soon afterwards. The record at Plymouth is more consistent with a maximum than a minimum. No auroras were observed at Upsal in 1733, 1754, and 1735, but none also were observed in 1738, the year of the next spot-maximum. In St. Petersburg the number of auroras had declined from thirty-six to six, but only six were seen also in 1729. If the influence of the secular change, which raised up a secular maximum in 1730, could be eliminated, the residual phenomena might be more consistent with the fluctuations in the solar spots. 7. A spot-maximum is assigned to the year 1738. In Italy an aurora-‘maximum comes one year earlier. In France no auroras are recorded between 1737 and 1750. In Holland forty-two auroras were ob- served in 1738, but more in 1736, 1739, and 1741. In Germany no auroras were observed in 1738, but thirteen in 1736, and eleven in 1739. In Wittemberg one aurora was observed in 1738, eight in 1737 and 1743, and eleven in 1742. In Plym- outh as many auroras were seen in 1738 as in 1742, but not so many as in 1736, 1737, 1739, and 1741. In Lincoping the maximum number of fourteen falls upon the year 1738, but the number sinks to two the following year, the series coming to an end. ‘Twelve were seen at that place in 1734. In Upsal auroras appeared in large numbers in 1739, 1740, 1742, 1743, and particularly in 1741, but none in 1738. In St. Petersburg the number of auroras increased from seven in 1738 to twenty- nine in 1742. In America no auroras were seen in 1738, but five in 1741. 8. The spot-minimum of 1745 comes next under examination. In Italy only two auroras were seen in that year, still fewer in the preceding and following years, but six in 1750. The minimum in France conveys no meaning as it existed for twelve years. In Wittemberg only one aurora was seen in 1744, 1745, and 1746, and none in 1749, though the latter year is so near the spot-maximum of 1750. In Germany the auroras decreased after 1759, but there were fewer in 1742, 1743, and 1744 than in 1745, and thirteen in 1746. In Holland there is a very decided mini- mum in 1744 and 1745. The small number of auroras registered by Musschenbroek in the year 1740 is probably to be explained by his change of residence from Utrecht to Leyden. In Zwanenburg the minimum of 1745 is unchallenged. In Plymouth, also, a satisfactory minimum falls upon the same year. In Upsal there is a minimum in 1744, though fifty auroras were seen in 1746. In St. Petersburg only one aurora was seen in 1744 and 1745, but only one was seen in 1749, and ten in 1746. There were six observed at that place in 1747. The minimum at Cambridge in 1745 and 1744 is unqualified. 9. The next spot-maximum is in the year 1750. In Italy there seems to be also a maximum of auroral display. The same is true of Wittemberg. In ON THE PERIODICITY OF THE AURORA BOREALIS. Bee 9 Germany seventeen auroras were seen in 1750, but not so many as in 1748, 1749, and 1752. In Holland there is a maximum in 1750, although two more auroras were seen in 1747 than in 1750. In Zwanenburg there is a strong maximum in 1750. At Upsal twenty-seven auroras were seen in 1750, twenty-two in 1751, but fifty in 1746, only one year after the last spot-minimum. At St. Petersburg, the five years which include the maximum do not supply as many auroras as the five years which include the pre- ceding minimum. At Abo there is a maximum, but larger in 1752. At Cambridge there is a conspicuous maximum. 10. Next comes the spot-minimum of 1755. In Holland twenty-two auroras were seen in 1755, 1756, and 1758, forty-two in 1754, and only sixteen in 1753. In Germany none were seen either in 1755 or at the next spot-maximum in 1761, and indeed only two between 1753 and 1768. At Zwanenburg there is a satisfactory minimum. At Upsal a small number were seen in 1755, but none in 1757 and 1758, probably on account of a break in the continuity of the series. At St. Petersburg only four auroras were seen in the six years from 1753 to 1758 inclusive. But this may have been the effect of the secular minimum which came about this time. At Abo there is a satisfactory minimum in 1756. The Cambridge observations accord well with Wolf’s theory, no auroras being seen in 1754, 1755, and 1756. 11. In the year 1761 is another spot-maximum. Few auroras were observed about this time, except in high latitudes. In Zwanenburg eight auroras were seen in 1759, and there the series ends. In Upsal forty-eight auroras were seen in 1761, but rather more in 1760 and 1759. In 1762 a clear maximum is made out for St. Peters- burg. At Abo it comes exactly upon 1761. At Cambridge the year 1761 is midway between two years when no auroras were seen, but itself is distinguished by fewer auroras than the eight years which precede and follow it. 12. In the year 1766 isa spot-minimum. In the same year was a decided aurora-minimum at St. Petersburg. It came a year later at Abo. In other parts of Europe auroras were very scarce, not only this year, but for the ten preceding years. 15. The next spot-maximum is in the year 1769. In Germany the aurora rose suddenly to a maximum in 1770. In Berlin and St. Petersburg it was later by one year. At Abo,it came in 1769. At Cambridge and New Haven it coincided with the spot-maximum. 14. In the year 1775 is another spot-minimum. There was an apparent minimum of the aurora in France, although as many auroras were seen that year as in 1769 and 1771, and twice as many as in 1770. In Boningen, Jena, Berlin, and Germany in general, there is a satisfactory minimum. In St. Petersburg there is a minimum in 1776, but a strong maximum in 1774. At Abo the number of auroras in 1775 and 1776 was less than in the four preceding years, but in 1774 more auroras were observed than in any pre_ 324 MEMOIRS OF THE AMERICAN ACADEMY. ¢€ vious year of the series, or during the twelve following years. In Franeker more auroras were seen in 1775 than at the following spot-maximum of 1779. In 1776 there was a minimum at New Haven and Cambridge, but an equal minimum at New Haven in 1771. 15. Now arrives the spot-maximum of 1779. In the same year are indica- tions of an aurora-maximum in Spain, Switzerland, France, Austria; also in St. Peters- burg, Copenhagen, Berlin, Jena, Carlsruhe, Boningen, and Montmorenci. In Brussels a large number of auroras were seen in 1778 and 1779, but none in 1780 and 1781. A large number were also seen at Franeker in 1779 and the two preceding years, but few in the three following years. While twenty-four were seen at Berlin in 1779, only two were seen in 1780. In Jena, Béningen, Montmorenci, and St. Petersburg, the number was small for 1780. At Abo not so many were seen in 1779 as at the spot-minimum of 1775, and none whatever in 1780 and 1781. In New Haven and Cambridge there is as good evidence of a minimum in 1779 as in 1775. A compari- son of the series observed at Cambridge with that observed at New Haven will, how- ever, justify the opinion that the Cambridge series is defective about this period. 16. The spot-minimum of 1784 comes next under consideration. In Brussels, Mann- heim, St. Petersburg, and Abo, an aurora-minimum falls upon the same year. In Italy, France, and Germany, in Montmorenci, Ratisbon, Carlsruhe, Prague, Sagan, Berlin, Copenhagen, and Spydberg, it comes in 1785. Only one aurora was seen at Jena in 1785, but none were seen in 1782. None were seen in Great Britain in 1784 or 1779. In Cambridge and New Haven the minimum belongs to 1784. 17. Another spot- maximum appears in 1787. In Switzerland, France, Germany, in Montmorenci, Paris, Ratisbon, Prague, Mannheim, Copenhagen, Spydberg, and Abo, an aurora-maximum is in the same year. In Berlin, St. Petersburg, and perhaps Brussels, it comes one year earlier; and in Sagan, Jena, and Great Britain, one year later. There were none at Prague in 1788 and 1789, and thirteen in 1787. No auroras were recorded at Carlsruhe in 1785, 1787, and 1788. In New Haven, Cambridge, and perhaps Salem, the year 1786 claims the aurora-maximum. How far the great number of auroras, generally observed at this epoch, was caused by the secular maximum, and how far by a subordinate maximum, it may not be easy to decide. 18. After a long interval comes the spot-minimum of 1798. This year contains, decidedly, an aurora- minimum, only two having been observed the whole earth over. 19. The year 1804 brings with it another spot-maximum. A feeble aurora-maximum can be traced in the observations made in Great Britain, France, Germany, St. Petersburg, and Abo, for the year 1804. The same remark will apply to Salem, and perhaps to New Haven. 20. The year 1810 is another in which the solar spots reach a minimum. Only two ON THE PERIODICITY OF THE AURORA BOREALIS. 325 auroras were observed anywhere, in 1810 and 1813, and none in 1812. It must be remembered that a secular minimum of the aurora approximates to the year 1812. 21. Another spot-maximum in 1816.° As this year comes so close to the secular minimum, we have to deal with a very small number of auroras, in comparing one year with another. There are indications of a slight aurora-maximum in 1817, at Ratisbon, Carlsruhe, Germany, Great Britain, Sweden, and Abo. At Arkhangel three auroras were observed in 1816, seven in 1817, and sixteen in 1819. In Maine there are none from 1809 to 1813 inclusive, but many in the years which cluster around 1816, though the largest number was seen as late as 1818. At Salem, also, the aver- age near 1816 much exceeds the average near 1810, the greatest number, however, being as late as in 1819, and none in 1816 and 1817. The observations at Boston and New Haven, so far as they prove anything, would postpone the aurora-‘maximum to 1818 or 1819. 22. Another spot-minimum follows in 1823. No aurora was seen in Europe that year, except in high latitudes. One aurora was seen in Abo, and two in Arkhangel. In Boston not so many auroras were seen in 1822, 1823, and 1824, as in the three years preceding or following. In Maine none were seen in 1822, 1824, 1825, and 1826, though two were seen in 1823. In the five years of which 1823 is the central epoch, far fewer auroras were seen in Maine than in the five years which preceded or followed. Parry and Von Wrangel have commented on the rarity and poverty of the aurora, even in arctic latitudes, during the winter of 1822-233 23. Seven years bring about the next spot-maximum in 1830. In Great Britain there was a regular increase in the number of auroras from 1824 to 1830, the minimum being zero, and the maximum being thirty-two. The decrease afterwards was far less regular. A similar remark will apply to Abo, the minimum being one, and the maxi- mum being thirty-four. At Arkhangel the number of auroras increases, but not with perfect regularity, from zero in 1824 to thirteen in 1831, and then the series of observations terminates. In Germany there were many more auroras at the maximum of 1830 than at the minimum of 1823, if the maximum and minimum are understood as covering each five years; but the largest number in a single year belongs to 1831. At Leith there is no indication of a maximum, unless it be placed as early as 1827. In St. Petersburg a maximum of twelve auroras was seen in 1830, although in 1829 there were none. In the low latitudes of Europe more auroras were registered in 1831 than are recorded for any other year since 1789; but the number was only ‘five. In America the observations made in the States of New York and Maine, also in New Haven and Wilmington, favor the theory of an aurora-maximum in 1830, and 1 See page 103 of this volume of the Memoirs of the American Academy. 326 MEMOIRS OF THE AMERICAN ACADEMY. an aurora-minimum in 1823. The Boston series of observations notices only the more brilliant auroras. More are recorded for 1830 than for any other year since 1819. But for two years before 1830, and for four years afterwards, there were none. 24. After a very brief interval, the spot-minimum of 1855 approaches. The European observations are consistent with the supposition of an aurora-minimum in 1833, as com- pared with 1830. However, thirteen auroras were observed at Wasa in 1833. The American observations, with the exception of those made at New Haven, agree with the European observations in the conclusion to which they pomt. 25. A spot-maxi- mum comes again in 1837. In the low latitudes of Europe, in France, and in Germany, at St. Petersburg and at Abo, there is a slight aurora-maximum in 1837, as contrasted with 1833. In Great Britain there is no indication of such a maximum. In Maine and New York, in Boston, Providence, and New Haven, the number of auroras has in- creased since 1833, although the increase has not always reached its limit in the year 1837. 26. A spot-minimum arrives in 1843. In France and Russia an aurora-minimum is possible in the same year. In Dunse and Christiania an aurora-‘minimum in 1844 or 1845 is more probable. In Germany and Great Britain there is nothing to justify the suspicion of an aurora-minimum in 1843. The observations made in New Haven, Providence, Cambridge, Boston, Newberry, New York State, Toronto, and possibly Worcester, permit the assumption of an aurora-minimum in 1843 as compared with 1837. 27. In 1848 is another spot-maximum. More than the usual number of auroras were counted this year in the low latitudes of Europe. In 1847, 1848, and 1849, more auroras were seen in France than in 1842, 1845, and 1844. In Germany, Great Britain, Russia, and perhaps Christiania, there is an apparent maximum about 1848. In America, at most of the places where regular observations were made, the year 1848 represents a period of greater activity in the aurora than the year 1843. The observations at Worcester and Jakobshayn are not clear in their utterance on this point; and in New York State the number of auroras observed in 1847, 1848, and 1849 was not so large as the number observed in 1839, 1840, and 1841. The secular maximum, which occurred some time between 1840 and 1850, would have some influ- ence upon the subordinate maxima and minima of this period. 28. A spot-minimum is found in the year 1856. In the low latitudes of Europe, in France, Germany, Great Britain, Russia, Christiania, the observations accord well with the supposition of an aurora-minimum in 1856. The observations at Providence, Cambridge, Worcester, Newberry, and Toronto agree with the European observations in their silent testi- mony. In New York State the great reduction in the number of observed auroras is partly due to other causes than the infrequency of the phenomenon. ON THE PERIODICITY OF THE AURORA BOREALIS. 327 In Tables LXXVI. and LXXVII. the number placed against each year of spot- maximum or minimum represents the number of auroras observed in that year, added to the numbers observed in the preceding and following years. In this more general mode of comparison the coincidences are more numerous, and the discrepancies are not so glaring, between the fluctuations of the solar spots and of the aurora, as when single years are used instead of small groups. But it seems to me doubtful whether, in any case, the agreement is sufficiently exact and frequent to justify the conclusion that the two classes of phenomena are associated, either as cause and effect, or as common effects of some remote and unknown cause. On the supposition of such an affiliation as Wolf advocates, it is wonderful that the long secular period in which the number of auroras slowly oscillates between such wide extremes of maxima and minima should be inconspicuous in the increments and decrements of the solar spots. In 1787, and again about 1849, when the aurora-curve towers to unprecedented heights, the solar spots scarcely respond to the summons which theory serves upon them to do likewise. During the aurora-minimum of 1758, and throughout the dismal blank which precedes and follows the aurora-minimum of 1812, the number of solar spots, though somewhat diminished, indicates nearly the usual amount of activity on the sun’s surface. LXXVI. NUMBER OF AURORAS FOR EACH THREE YEARS WHICH CENTRE ABOUT A MAXIMUM OR MINIMUM OF SPOT-FREQUENCY. S ‘ ‘ & 3 ri u 2 io. ! 2. o. s 2 = = 5 S = = 4 d 5 5 5 A 5 3 3 & g | Max. | 1705 2 2 2 Min. 1712 : 1 - 1 ° 1 Max.| 1717 1 47 14 61 : 61 Min. | 1723 2 93 Pilg |e iis 120? Max.| 1727 | 23 | 101 111 250? 2 ; 2 | 250? Min. | 1733 Gem ioe «| «182, |ep99 || 299 Matec iis || 148 | 129, | 982 5 ; By )e2Be Min. 1745 3 64 85 148 8 2 4 8 155 Max.| 1750 | .10 | 105 81 183 33 1 34 | 197 Min. | 1755 2 81 43 | 126 ! 126 Max.| 1761 9) 144 150 18 3 2 20 159 Min. 1766 1 1 12 15 11 é : 11 27 Max. | 1769 1 45 52 89 40 2 42 | 120 Min. 1775 13 124 89 188 28 - : 28 203 Max.| 1779 | 19 | 197 97 | 259 48 ; ; 48 | 282 Min. | 1784 | 16 | 133 87 | 207 50 50. | 233 Max.| 1787 45 331 218 453 150 - : 196? 522? Min. 1798 : 19 4 23 < ri A - 23 328 MEMOIRS OF THE AMERICAN ACADEMY. NUMBER OF AURORAS FOR EACH THREE YEARS WHICH CENTRE ABOUT A MAXIMUM OR MINI- MUM OF SPOT-FREQUENCY. Continued. : o* 2 o” 2 3 : 3 : 1 ° ° ; t ° ° 3 & & 8 3 & & 3 z 3 5 3 a 3 3 3 E Max. | 1804 ; 22 4 37 13 13 Min. 1810 ‘i 1 1 7? 2 2 Max. 1816 - 13 15 31? 6 5 6 Min. 1823 < 2 11 ? 3 = 13 ? Max. 1830 3 87 105 165 173 : 4 ? Min. 1833 3 26 24 ry 112 j 159 ? Max. 1837 3 33 105 ? 198 5 1 199 *Min. 1843 4 25 161 182 184 : 324 ? Max. | 1848 2 108 190 253 386 129 32 ? Min. 1856 c 10 69 if 144 . ? LXXVU. NUMBER OF AURORAS FOR EACH THREE YEARS WHICH CENTRE ABOUT A MAXIMUM OR MINIMUM OF SPOT-FREQUENCY. : i) y S 4 A Es g 8 a A so a 3 uf 3 ct ea tag en (“ea =a Da Pe Dr i Beli Sey a VOIELTODaleecatateela aeelll etal) | edhe 1 : Friel Gel Path el eh eH at : : Wo LET Ss SIG SS Obl 31 10 iy eile} || Te as | A eae eG 7 5 NE eLTeT | 23a ee ee es | 400 15) | 4264) 42013 m: | 1783) 7 (106 | IL | 69 | 20') 27 | 14 |) 42) 31 M. | 1738 | 17 | 1 | 18 |131 | 18 1| 50] 36 : mee Wade Bh ea |) ole4 Or! 16 |) ap] Te : 7 M.| 1750 |10|} 1| 7/73) 49] . Bi) sil || TO) eee) Be 2 : ; x Tite LTS eee ll Aes IP SOnl meee Pa er Dl) ae ; ; : i MS ELTGM| Ao lieealh coolers nee . 1110 | 46] 40} 18 re hee s(t Si aa ae Dil ee) Pepe me Sorel stl eect Gale 1 : AE | age) Pe ie Be |) Be) {oe Balt 26) D6alab il ag Meelis Woh 2 Week eta Th || tei eerste asa oe MeN RUT TON mee aiesi te. ees eDee|e4ll FW eS7aleloas0uleo Teel 7s4) Ga S4ei Ailes lezen _ | 821 38 | 22 |) Bo Mo i7s7 ley | 73) 2) ST eles 96n(155.| 600)" 639) (58) sis 97 THT ELIS elite Oil Gest necthl|, eal wedi 15 ' 2 1 i : EM TOE a ZEN i OI) So 16| 8 elt Tal Te || al Tig LST OM elt Hh te ees le STG) ce f 1 ’ : 2 WC TG ee Tle] Saal) 7 2 ; 2 1 med SIUM ||) solely alee | det ae il |) 6 a ee ae ; Me t830./673,) bith oe foe Necietl Seem al! Fal nT a et Bs Su baal m. | 1833 3 i f : Pye ie ait | FEM aly 14 | 4" 4 Wes |p IESE Y/ Ih 2 || 1 6 22 | 8 5 | 24 ~ || BE | Be s ot me leash ees es 11 56 | 109 ? 20 | 31 6| 20] 8] 56 Weave erty eye) rE ten ee levis) i) i sly Sy ipa | 9 33 |103 | 31] 23] 32 | 178 Nfereaya| a1 55 Gol] eee peal eee (ee | cat 1 25 : 2 1] 15 | 106 ON THE PERIODICITY OF THE AURORA BOREALIS. 829 There is reason for thinking that the abnormal disturbances in the sun’s crust are coincident with unusual magnetic perturbations. On September 1, 1859, Carring- ton and Hodgson were watching the sun at different observatories, and noticed a spot crossing the surface, between 11” 18™ and 11" 23™ a.m. Almost at the same moment, viz. at 11" 20", the self-registering magnetic instruments at Kew recorded the violent jerks to which they were subjected, and a magnetic storm extended widely through the earth. Great stress is laid upon the fact that there was on the same day a signal display of aurora, which was extensively seen, and so potent as to interfere with telegraphing, and set on fire the telegraphic offices. Upon this coinci- dence Mr. Carrington makes the following judicious comment: “While the cotem- porary disturbance deserves noting, he would not have it supposed that he even leans towards hastily connecting them. One swallow does not make a summer.”? It is not a serious objection to the supposed connection between the solar spots and the aurora, that, in this particular case, the passage of the spot was confined to a few minutes, while the aurora lingered for many days; for a cause may be sudden and short-lived, while its effect is more lasting. But the fact that the effect anticipated the cause, that the aurora was brilliantly displayed as early as the 28th of August, and more or less conspicuously on the three following nights, does not admit of as easy explana- tion. If the outbreak of special spots upon the sun can be associated, in time, with extraordinary motions in the instruments which register the earth’s magnetic condi- tion, the foundation is laid for the hypothesis that sun-storms and aurora-storms are remotely, if not intimately, linked to one another. For one of the first fruits of the magnetic crusade originated by Humboldt was the verification, by abundant examples, of what had been distinctly pronounced before, viz, the synchronism of auroral storms and magnetic storms. In the last {century the Abbé Mann wrote:* “I have frequently observed the irregular magnetic variations during great auroras, as in 1767.” Arago, watching his needles in Paris, saw by his intellectual vision what Parry beheld with the natural eye. And Kupffer was so confident that auroras, which might even be shrouded from the upper world by clouds, were faithfully announced to underground observers throughout the whole line of Russian Magnetic Observatories, as to think that the direct observation of the aurora might be neglected even when the weather was propitious. The two following Tables have been prepared to facilitate the comparison between the Maxima and Minima of solar spots and auroras. 1 Month. Notices of the Roy. Astron. Soc., XX. 13-15. * Mém. de I’Acad. Brux., I. 265. VOL. X. 42 330 MEMOIRS OF THE AMERICAN ACADEMY. _ LXXVUI. AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. sg to ‘ 3 a 5 es Z 2 = 3 Bg Pe A ee ee 3 = Ra a a & = = 5 ' & a S 1 : 4 i : 2 1 1 1 1 2? 5 - 1 1 > : = = z 5 6 9 6 3 1 8? 8? 5 : 4 2 : 2 2 2 6 : 4 : 1 1 2 7 10 2 3 S) 1 6 6 6 f 3 A 4 11 3 4 1 ~ . 28 4 2 1 9 2 5 15? 15? 15? 5 : . = 15 5 3 iy 2 ; 2 10 1 4 12 : 13 4 5 10 1 : < ; 17 18 10 14 4 8 8 A 18 4 6 8 11 c 1 9 9 4 42 6 11 7 2 - 5? st) a 7 11 7 6 5 : 41 46 5 iby 15 12 2 1 fs 19 27 3 2 12 10 9 1 28 33 3 1 42 5 3 3 ; : 9 | 10 43 5 i 6 E 1 2 6 13 64 1 11 10 1 1 8 7 38 9 3 : 1 5 42 6 4 4 11 51 8 1 ; 2 2 4 3 5 4 44 7 11 lf 17 6 ON THE PERIODICITY OF THE AURORA BOREALIS. 331 AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. Continued. : to ; a 8 8 2 a 3 3 ieee! i || 2 | 8 at ese a toes z B 3 3 3 é 3 5 2 E 3 e 8 ieee Na.) 2.) 2 1-8 |e oh e@ We oheg : : 1700 : : . : 5 - 1701 1 : 3 : 5 : 1702 5 - : : : 5 5 ; 5 5 1703 1 C > : . . : 8 : : 1704 : : : : : 1705 Max. - : . : : : Z : F : 1706 4 ; , c 3 Z ; é 1707 q : : : : - ‘ - 1708 5 i B ; 1709 F 1710 1711 1712 Min. 1713 1714 ‘ a : > . : 2 5 1715 1 ‘ : 5 5 : : E : 1716 5 ; : : : ° 3 3 3 P 1717 Max. 1 9 3 3 5 : F ‘ : 6 1718 2 : P : 5 é 2 1719 5 a 1 5 : , : : : 5 1 1720 ;: c 5 : 5 . . : 3 ; ; 1721 : S - 1722 ‘ 1 ‘ 1723 Min. é 4 3 s 5 : 3 : : 1724 F 5 A : : : 5 ; ' 1725 : ef ; 2 3 5 " F : : 1726 E 8 , 11 5 . 29 ; 3 3 Vey Max. 13 27 . 25 c 5 19 : 3 2 1728 8 31 ‘ 6 4 C 8 4 : 5 1729 7 52 ; 36 22 fs 1 ‘ 1 : 1730, 6 36 : 18 3 ‘ : 1 é a 1731 2 Fi 42 3 12 : : é ; s 1732 9 1 : 4 6 , - 3 Z ; A 1733 Min. 3 12 13 5 f 5 4 é - 1734 2 é 6 7 P : , ‘ ‘ ; 1735 11 14 alah 9 : 12 F 3 s 1736 9 5 11 10 : 1 29 | 2 5 . 1737 6 14 7 ~ : F F : a 1738 Max. i 45 2 19 4 4 : 3 1 3 1739 4 By 5 13 : : é : . ‘ 1740 7 83 26 5 1 5 ; 1741 6 | 47 29 2 4 1742 332 MEMOIRS OF THE AMERICAN ACADEMY. AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. Continued. Years. 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1703 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1798 Italy. Bower o- Wee: — Re bo ST Or Or bo 09 Goes Spain. poop bs + ° pa. Switzerland. boo Orsi wes Ft Montmorenci. nono: + Paris. hm rR Oo OO: _. France. Austria. Bere: hbo OO OO: — KO NWR RE OeY Wittemberg. E , | Sl a-he ao) |) eel” ee emi A = a S ra] i= 1? 17 5 14 1 9 2 9 13 22 13 36 334 24 : 22 18 : il? 34 ‘ 10 Dili 22 33 ? : 16 5 42 We, 22 bl é ; 92 1 7. 2 1 1 2 5 2 0. 3) 7 19 29 i] 1 24 25 i 2 1 15 16 P 9 20 23 1 5 13 19 4 il 4 4 3 1 . 4 4 10 4 4 12 15 6 5 5 11 16 22 18 12 24 31 iby 7 5 2 9 8 4 15 53 F : 12 32 4 i 5 12 47 6 3 3 6 21 Z , 1 3 19 10 . 2 24 51 34 10 11 74 33 16 2 62 18 2 2 31 24 2 38 j F 25 13 2, 33 6 1 1 For the observations at Ratisbon, Carlsruhe, Sagan, Mannheim, Prague, Copenhagen, Stockholm, Salem, Ipswich, etc., see pp. 334 and 335. 1 Observed by Héslin, and recorded in Meteorologischen Beobachtungen. ON THE PERIODICITY OF THE AURORA BOREALIS. 333 AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. Continued. = % Fs S g 8 | 4 Z a é & g Pe hele | | 2 | 2 ee | 5 2 q a 5 3 a é 3 a E g 8B I a & & a & = a a 2 ‘S) a a 3 6 6 47 29 4 || 1742 3 4 4 AT 9 2 || 1748 ; 1 3 2 15 1 1744 | 1 : 2 2 20 1 1745 | Min. 8 2 4 4 | .50 10 1 7 || 1746 10 fl 5 5 36 6 10 || 1747 10 4 3 3 40 2 2 1 6 || 1748 3 2 f 32 1 6 1 ; 10 || 1749 || 63.8 1 || ale 3 27 4 12 3 A 17 || 1750 || 68.2 | Max. 9 2 22 5 6 ’ 5 || 1751 || 40.9 is} |) Tal 40 12 16 2 || 1752 || 38.2 4 5 34 9 1 || 1753 || 23.1 4 4 i ; 10 5 ; : 1754 || 13.8 4 9 1 2 : ; : 1755 6.0 | Min. 8 15 1 3 P ; : 1756 8.8 8 : 1 1 1 6 || 1757 || 30.4 10 1 A 1 6 4 || 1758 || 38.8 ; 8 51 6 13 5 || 1759 || 48.6 50 10 11 6 || 1760 || 48.9 48 11 15 5 1761 75.0 | Max. 12 25 14 7 || 1762 || 50.6 7 11 1 6 || 1763 || 37.4 3 12 9 11 || 1764 || 34.5 ; 8 6 7 || 1765 || 23.0 1 6 1766 || 17.5 | Min. 4 4 1 3 || 1767 || 33.6 | 3 7 ; 4 6 || 1768 || 52.2 2 10 13 1 9 16 || 1769 || 85.7 | Max. 13 6 i 4 14 || 1770 || 79.4 10 27 12 15 || 1771 || 73.2 14 21 19 2 7. \\ 1779) || 4912 23 1 31 15 5 16 || 1773 || 39.8 34 : ‘ ; : : 48 21 : 6 15 || 1774 || 47.6 39 ; ‘ 1 ; : 23? 7 q 1 5 || 1775 || 27.5 | Min. 21 : : ; : 12 6 ; 4 || 1776 || 35.2 36 26 12 6 14 || 1777 || 63.0 22 ‘ é : ; ; 31 6 : 5 16 || 1778 || 94.8 27 : : : : t 37 6 : ; 4 || 1779 || 99.2 | Max. 4 : ; 19 : 25 3 1780 || 72.6 1 29 25 13 || 1781 || 67.7 4 1 30 3 20 21 || 1782 || 33.2 17 1 14 23 || 1788 |} 22.5 7 1 4 || 1784 4.4 | Min. 14 6 13 || 1785 || 18.3 16 40 7 24 34 || 1786 || 60.8 27 10 36 15 27 «|| 1787 |} 92.8 | Max 53 10 20 19 26 || 1788 || 90.6 45 15 19 21 21 || 1789 || 85.4 36 4 22 3 . || 1790 || 75.2 37 , 10 3 ; 1791 || 46.1 23 2 13 1 1792 || 52.7 13 2 7 2 2 || 1793 |} 20.7 6 2 1 1794 ||} 23.9 1 Observed by Huber, and recorded in Harlemer Abhandlungen, ete. 334 MEMOIRS OF THE AMERICAN ACADEMY. AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. Continued. | . | B : | A mle g dal 3 | 8 | Wh cS - & S > So | & |) é é 2 Sie gels é a ee ee 8 = 1778 | 12 20 ; 3 : 16 5 4 1779 || 17 40 2 23 ; Sa) kote ll 1780 | 8 "13 1 19 5 9?| 5 1781 |! 16 1 16 8 12 11 26 53 4 F 1782 vf : 7 3 4 7 16 5 32 : 1 11 1783 || 13 2 15 8 10 13 20 | 12 47 5 11 1784 || .5 5 13 3 4 8 8 4 21 3 : 3 1785 2 2 6 : 5 13 19 1 : 2 1786 8 8 14 4 4 28 20 8 51 2 | 16 9 1787 || 11 20 ae a ee 33 390 | as Fae |) IO! |, 2Oe 10 i7Sei\|\ Mos 12 18 6 42 27 ; 62 | 16 | 53 2 || 1789 5 12 18 6 6 32 10 P 31 2| 45 1790 8 9 1 24 18 4 38 2 | 36 || 1791 3 3 1 15 10 1 25 : 37 1792 || 2 : 3 d 22 9 i 33 2 | 23 1793 2 1 3 ‘ : 1 Ts 1794 || -1 3 3 6 1795 2 2 ; 3 || 1796 1 1 1 1 : lla797 || 3 el Erg 1798 || 1 1 . E 1799 2 2? 2? ‘ 2 1800 | 2 2 3 1801 ; 4 1802 ! 1 4 1803 1 1 6 1804 2 2 2 6 1805 1 1 4 1806 : 1 3 1807 1 ; 1808 1 1 1809 1810 1 1 1811 , 1812 | 3 1813 | : 2? : 1814 | 2 2 3 1815 | 2 2 : 1816 1 5 1 2 1817 rt 3 3 7 5 1818 1 i 1 2 1819 1 1 3 1820 2 || 1821 4 l} 1829 | 1? 1 1823 1824 1 * The observations given by Bockmann are different. Gilbert Ann., VII. 32. ON THE PERIODICITY OF THE AURORA BOREALIS. 335 AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. Continued. = 2 : é g g 3 5 = = 5 s 5 a i a 2 eee 2 ie |g | 2 PE | ge Pee a az = 3 Zz S = OS = < Ps & | ] 31 6 5 16 A 1778 37 6 4 : 1779 19 1 25 ; 1780 29 25 13 19 i! 1781 30 3 20 21 20 1782 17 1 14 23 14 1783 7 18 1 1 4 ; 1784 14 12 | 6 13 ; : 1785 40 24 7 |] 24 34 41 26 1786 10 27 36 15 27 33 28 1787 10 20 19 26 23 rlcfelss | 15 19 1 21 21 37 1789 4 22 3 : ll 1790 : 10 3 ; 11 1791 2 13 1 d 6 | 1792 2 7 We 2 2 6 || 1793 2 1 1 | 1794 2 2 \] 1795 1 1796 1 1797 E 1 5 1798 | 1 eee 1799 | ; F : 1800 | : 2 p || 1801 30.9 1 5 1 1 |} 1802 || 38.3 P 3 3 4 1803 || 50.0 3 7 2 4 || 1804 || 70.0 | Max 1 1 | 2 3 1805 || 50.0 1 2 2 || 1806 || 30.0 1 | 2 : 2 1807 | 10.0 1 : f 12 | 1808 2.2 d 2 1809 || 0.8 | 1810 0.0 | Min. : | 1811 0.9 f z |} 1812 || 54 i BS |} 1813 |} 18.7 2 3 S || 1814 20.0 1 : 2 | 1815 || 35.0 : : 1 || 1816 45.5 | Max d 2 ; : 3 | 1817 43.5 : 3 1 8 | 1818 34.1 2 ; | 38 5 4 | 1819 22.5 5 , 1 1 1 1820 8.9 1 1 |} 1821 4.3 : 1822 2.9 1 2 1823 1.3 | Min. 2 4 1824 6.7 | For the observations at Arkhangel, see p. 337. 336 MEMOIRS OF THE AURORAS OBSERVED IN DIFFERENT YEARS, AMERICAN ACADEMY. ARRANGED ACCORDING TO LOCALITY. Continued. g : z z cane Mle a : = 3 g F = ze a 3 | 3 5 E oR ee ie Fe Jee es P= nen a z | Ss | ge) oe 2 Bae Le ee sede BSUS Ve Siege ane 1814 1 : : 2 3 ; 1815 - c < 2 : a 1816 5 S 1 Be 1817 1 1 le 5 a 1818 : ‘ 1 2 1819 1 3 : 1820 : 2 4 1821 ; : 4 é 1822 1? 1477 < : . 1 - 1823 A C 5 - 5 5 é 1824 3 : 5 : 1 k : 2 | 1825 c c > 5 1 8 1826 | : : - 1 : 2 7 1827 2 2 2 : 10 8 1828 J c 5 5 11 2 1829 - C 1 5 < 18 8 1830 - 5 5 ; 2 2 ; 5 32 4 1851 : 3 1 1 5 4 1 1 23 5 1832 | z . F : 1 ‘ 4 5 2 1833 : - 1 1 2 = 2 5 12 1 1834 | 4 5 : 3 : 1 2 - 4 2 1835 3 1 2 5 2 : 1 3 5 4 1836 | 1 1 1 : 1 5 5 2 : 1 : 5 1837 | 1 c 4 7 8 F ~ 3 - 3 é 12 1858 5 5 : 4 3 3 a - 1 a 1 5 C 1839 : 3 1 4 3 4 4 4 4 6 4 18 10 1840 3 ; 1 4 4 1 1 i! : 4 : 9 10 1841 : 3 3 . 2 2 2 6 5 a : 1842 || . 1 - 1 1 2 2 5 5 3 5 2 1843 : 2 - ‘ 1 2 4 6 4 : 4 : 24 1844 | 1 6 ‘ : 1 4 | 10 a - C : 30 1845 2 1 E 1 2 9 15 11 : ‘ 1 47 1846 3 2 z : 5 11 14 11 2 1 19 1847 1 1 1 if 6 - 9 15 12 : 5 5 26 | 1848 || 1 2 2 3 1 yee | patil Bea) |) al : 3 : 53 1849 1 1 1 6 5 2 5 13 > 5 : 47 1850 : 5 ; . 4 2 4 3 6 ells < 27 1851 a 1 : : 1 3 3 8 1 1 1 60 1852 || . 1 : é 2 2 b 16 = 5 0 66 1853 |). . 5 ; 2 : 3 1 ; 58 1854 f 5 S 1 : 5 . 3 1855 || . : 5 5 5 é c 1856 || . 3 3 SN es : : 1857 E : : : . 1 : 1858 || . 3 - 1 1 2 : : 0 15 1859 || 3 4 1 4 3 6 21 4 3 2 28 1860 3 c 3 4 24 3 1 2 5 1861 1 2 1 1 13 9 1 a 1 F 1862 2 8 1 1 3 15 : 1 9 . 5 1863 3 : 6 A ; 3 12 5 5 . 3 1864 41 : i A 1 26 1 2 5 1865 || 1 1 ; 1 4 33 4 2 : 1866 : 2 1 1 2 8 1 Greece. * Lisbon. ? Schmidt’s series as given by Wolf, from Grunert’s Archiv. S. XX vi. ON THE PERIODICITY OF THE AURORA BOREALIS. 3387 AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. Continued. F 22 E rs a i 3 | a g Ss ee ae ae ee ae ae g HI & 2 E 4 3 3 2 $ 2 a | 22 4 E Ee ine euler B02) SW ge | Se eS seneae aaes : 1 20.0 : 2 | 35.0 1 2 3 45.5 | Max. 1 3 2 7 | 43.5 5 1? 5 34.1 2 2 16 | 22.5 5 5 11 8.9 1 ‘. 4.3 3 2.9 : 5 1 2 1.3 | Min. 2 2 é : 4 c 6.7 1 1 7 : 12 Oy alge! ; : ; 11 2 | 29.4 2 2 ; 17 19 1 39.9 1 1 : 24 22 4 | 52.5 : ‘ ; 27 3 4 | 53.5 12 12 1 Pp 34 1 12 59.1 | Max. : 5 5 ' 27 9 13° | 88.8 ; 1 1 5 6 6 1 | 22:5 : 4 4 : 2 8 13 2 7.5 | Min. é 2 2 : : 3 4 11 11.4 : ‘ : ; 8 11 6 5 | 45.5 : 4 il 1 é 13 14 ill) ae _ 96.7 : ’ 2 10 22 2 4 25nlee . {111.0 | Max. ; 7 2 20 28 ; 6 | 108 82.6 : 38 : 8 30 a 3 | 149 68.5 : 43 é 18 40 5 2 8 51.8 ; 42 4 5 35 : 2 : 29.7 : 49 6 3 49 5 1 19.5 20 10 ; 1 38 : 6 8.6 | Min. 30 13 , 2 22 1 13.0 47 10 : 7 18 3 33.0 17 16 3 11 39 5 47.0 18 30 4 22 38 6 79.4. 26 : 2 21 38 1 100.4 | Max. 26 1 5 43 ; : 95.6 4 5 25? 1 64.5 2 8 17 9 61.9 ; 13 45 9 52.2 : 12 26 7 37.7 ; 6 ; 35 ' : 12 19.2 : 1 DY |) Gy) : 2? 8 6.9 ; 2} 24 24 é ; 9 4.2 | Min. 1 6 | 15 15 3 21.6 3 12 {| 39 | 39 8 50.9 4 23 | 46 | 46 2 6 12 96.4 5 21 34 | 34 118 | 24 8 98.6 2 rN) cy yy 9 | 15 5 77.4 3 AM 5004\) 27 mt \\ 10) i ; : ; x 59.4 3 15M Do ee obi LOM ele : A coe ‘ 44,4 1 Bi |B |) oy 7 9 ; : : : 5 47.1 2 | Bey ae oy 5 : : : 5 : : Bie i rl 3 | 10 1 The observations at Arkhangel were made by Silvestroff. See Mém. de V’Acad. St. Petersburg, S. 6, T. IV. et V. pp. 237 etc. See observations in Iceland and Nis’hne Kolymsk in 1820-3. VOL. X. 43 338 MEMOIRS OF THE AMERICAN ACADEMY. AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. Continued. 5 : FI 3 3 g : é a See le ee eer eee: Ae eed |e g ll #¢ |S | ge a4 (S ) EF: | ee) Se |e CE eee ae Be | ao ge) 2 ge] |e | a) SSE IE ier eee eee 1814 ; 2 5 3 1815 : : 2 1816 : i 1 1817 : f 3 1818 3 tee |) a2 8 1819 3 4 ; 4 1820 | af 1 weet 1821 | ; Sell aks 1822 1 A : 1823 | ; ; A 2 1824 ; ; : ; 1825 ; : 2 ' ; 1826 : : 2 ; 1827 | 6 7 2 14. he 1828 | 3 6 21 | 2 1829 3 2 2 | 7 1830 16 4 3 80 | 9 1831 12 2 55 | 2 1832 6 Delo al ; 24 : 1833 ie | 7 3 ; : : : oy i) 2 1834 S 9 . ; ; : = les < : 1835 | 1 1 6 3 - 2 : : 30 1 We 1836 : 5 | 6 : 1 ; Be [PGi eo : 1837 1 ; Wt Aol x7 : 3 : 5 | 50 | 2 1838 4 eh Song : a : 6 | 42 | 10 : 1839 4 45a) 19 gi 3) as aA aie : 1840 1 5 Sl ea |e) 2 | 24 8 ih owS Al) oat aes 1841 2 || YG | Gps 2 114 Fi hes 5 WEAO 1842 2 reo (oe Oe ame 9 aN (EI 2 | 35 22 1843 ; 6e)| 101 3 5 6 4 | 56 17 1844 i Dl) 10) 2 6 2 2 | 30 17 1845 Th RYO || 2 7 8 4) Da 15 1846 Be ee NR a fe 7 5 | 47 38 1847 5} 1S 9 1 5 3 | 46 35 | 1848 || 2 20 | 14 | 20 1 Se Ga eeS i own Te 1849 1 30 | 9 4.4 Be alelSu viavay aed eine 1850 1 91 | 12 | 14 6 S290 50 1851 3 42} 9 | 11 qT as - | 58 73 1852 22/15 | 44 4 | 10 ; 102 | 36 1853 1 py | SYN) 6 | 16 ; 63 | 39 1854 2 15 | 7 | 26 12 | 15 i 54 | 50 1855 ’ 2p None ! 4 6 46 | 37 1856 ; 1 7 ’ 5 2 34 | 384 1857 ; 1 1 6 1 6 Fe fesile || 0yR) |) oa 1858 : 1 5 | 24 ee ae ge SL lb Sey | Zin 1859 1 3 9 | 15 aleit Wats 6 5 eaey |lP ai 1860 1 1 3 9 5 Pea ae ; eae) 22 1861 ; 6 a 9 5 43 | 36 1862 9 7 48 | 26 1863 1 L 44. || 1864 3 34 1865 : : ; ; : 2 : i : | ; : za eBo 1866 é : : : : ; a MRS : i ' ; = teal 1 Dorchester. : 2 Williamstown. ® Canada. ON THE PERIODICITY OF THE AURORA BOREALIS. 339 AURORAS OBSERVED IN DIFFERENT YEARS, ARRANGED ACCORDING TO LOCALITY. Continued. = Montreal. Kingston London. Quebec. Newfound- land Sitka. | Hudson’s Bay etc. | Winter Isl- and. Cumberland House Fort Enter- prise Tgloolik. Fort Frank- lin, ete Winter Har- bor. Solar Spots. SOralea Rene ealpaa: bo bo + Ov Lake Athabasca - CuNro@m. -« _> Or c—~ Wee eo Der oO 25 53 a | ea lor} So bo 2S ilo} , | Davis Strait, 158 i - Ler ete Fort Reliance. | | . , . aq » bo © VR. Harbor. 174 125 Jakobshayn. + 30 86 Coro? Fort(Confidence.. = = 5.0 Go Oise « . = Gy Felix Harbor. bo . - « bp Fort Simpson. 47 GT 16 11 x Sheriff's Harbor. . Repulse Bay. « + + eb for s~ iy 20.0 Max. Min. Max. Min. Min. Max. Min. Max. 1 Lake Superior. * Fort Norman. ® In Lat. 75°. * Port Kennedy. 5 Port Bowen. ° Behring Sea. T Northumberland Sound. 5 Lancaster Sound, etc. 340 LXXIX. AURORAS ARRANGED ACCORDING TO YEARS, ZONES, AND HEMISPHERES. MEMOIRS OF THE AMERICAN ACADEMY WOLF’S CATALOGUE. LOVERING’S CATALOGUE. 5 5 o” | a, . 3 = S : °. 2 a eeu i SPA | oe Wee hee S g g 2 Sale 2 3S S gS 3 a eraliaes gS 3 RS = BS 3 z 3 3 3 | 3 PS 3 = z = 3 mS | & 4 eS a a hi A 4 4 4 4 a 8 4 4 F 1700 1 : 1 A 1701 F : A . 1 iL 1 1702 1 1 Fi - C = 1703 ‘ ; “ 1 1a) ek 3 3 1704 || 1 5 1 1 . 3 1 1 | Max. |} 1705 ‘ ‘ 4 : 1 a 1 1 1706 1 ‘ 1 : 9 Th |) aR hal 1707 8 8 16? 5; 6 1 ai 7 1708 | 3 1 4 2 4 A 6 6 1709 “3! : 3 ; 3 3 3 ALORS a 3 Bi 1 2 2 2 1711 z 1 1 il 1 1 | Min. || 1712 5 : 3 2 2 ;: 2 2 1713 - - : 3 ; 1 A 1 1 1714 2 1 A 1 Ee fe 1 iL 1 1715 ; : 2 > ike || Spee 3 | 19 } 19 1716 : 15 2 15 ; i 16 4 | 18 | 18 | Max. || 1717 z 14 3 17 5 2) 225) mt 30" |) 30 1718 eS 9 29 Beit 2B GR) 3 | 41 | 41 1719 Sy | BAe : 347]; 2 a | 30 2 || 3333 || SB 1720 2 | 26 1 31 1 i) ea) {WEAR a 29) | 29. 1721 5 23 ‘ 24 1 : 44 | 14} 59 | 59 1722 1 a Es] I 56 ii 25 | 17 | 37 | 37 | Min. || 17238 1 3 all 3d - LOW La 427 |. 27 1724 F 15} 0: 27 5 16a 24. | 32) 32 1725 js Pat |) aly 34 By || Tk | ewe |) giGi |) Bey jess 1726 1 | 40 | 16 ~ 49 12) L |} 267) 50 |) 72 | 94 | Max.|| 1727 ||} 12 | 18 | 46 128 | 90 > 10 59 | 59 |101 {112 1728 |}10 | 43 | 49 | 19 {111 2 3 Sy | 22 |) GR |G} 1729 ON Bera Eye | se he r(3) 18 | 3 | 52 | 89 /180 |130 1730 |}11 | 53 | 90} 1 {109 1 3 34 | 46 | 68 | 68 Tat ees | AY. 67 || 1 4 32 | 85 |103 |103 1732 o> | 72 | 87 134 1 19 | 15 | 35 | 35 | Min. || 1733 ily | Peay < 58 1 18 | 27 | 44 | 44 1734 TE) C6 I Bis} 107 3 39 | 33 | 67 | 67 1735 3 | 55 | 35 96 6 32 | 25 | 54 | 56 1736 6 | 62.) 51 110 OS S25) LE 45s 05 1737 ||11 | 50 | 50 109 2 3 21 . | 24 | 24 | Max. || 1738 3 | 44 | 23 67 4 42 39 | 74 | 75 1739 4'| 54 | 56 106 3 2 Pile || st) || auf || Bvt 1740 1 8 | 44 50 Lat. P. C.-90°. | America. . ee mle) =tihO le) ce) te) Tele ae) Ge SD ROIS WG OG Total. » The auroras observed in every part of the Eastern continent are included under this designation. Lat. 0°- 46°. ON THE PERIODICITY OF THE AURORA BOREALIS. AURORAS ARRANGED ACCORDING TO YEARS, ZONES, AND HEMISPHERES, Continued. WOLF’S CATALOGUE. Lat. 55°-Polar Circle. Switzerland. eo so b STCO rR Cos ROR ee OH worr-: me bo Oo bo ~I thet is) _— oo a> i ~ Oo Ore bo © bo (te) oo (Xs) oo Solar Spots. Min. LOVERING’S CATALOGUE. ea) ee eciell= : & 3 -¥) I ra ell Neca Solis! P Bis | ea eee et eee Rs = S21 eS sao lie 1741 || 3 | 34 | 95 129 || 5 1742 || . | 28 | 65 Sz ied 1743 || 1 | 18 | 56 69 || 2 1744 if UY) Ip ales 28? : 1745 || 2 | 14 | 20 86 || . 1746 || . | 38 | 50 84 || 8 1747 || 3 | 45 | 20 64 || 10 1748 1 4D az 74 6 1749 || 3 | 34 | 32 66 || 11 1750 || 6 | 43 | 27 67 || 17 1751 1 28 | 22 50 5 1752 |e | 74 | 40 76 || 2 1753 18 | 34 51 || 1 1754 || . | 39 | 17 Bet 1755 2 PAN Wil 35 A 1756 || . | 20 | 15 35 ||. CSTW. | S2e| wae e leSeellene 1758 Pita een eral we 1759 SUiepetes eeeaiiee 1760 . | 58 58 || 6 1761 2 ae 56 5 1762 3 | 33 36 || 7 1763 2/1 8 10 || 6 1764 iy |} 16; 15 12 AGH ae alee el kee. Meo ullaeg 1766 z 1 - 1 * WAGTE des lope fae kale Tee le | aul igh. lease 1769 || 1 | 11 | 311 1 | 38 /| 19 1770 , O00! | - 38 14 1771 ||. | 34| 97 56 || 15 1772 || 6 | 30 | 22 50 || 10 1773 || 8 | 46 | 32 69 || 18 1774 ||13 | 48 | 50 87 || 19 1775 || . | 45 | 23 61 || 5 1776 S Bil |} aly 40 4 1777 2 67 | 25 78 15 1778 || 6 | 66 | 33 81 || 18 1779 || 8 |107 | 44 129 || 4 1780 || 5 | 24 | 20 49 || 26 Lat. 46°- 55°. Lat. 55°-P. C. Lat. P. 0.-90. America. 341 Rb e Or i a "eS NNOONN DOW: i OPPs NNONNDOK Ds + 26 a i el eel H= OO Or O10 OO OH > CO 342 MEMOIRS OF THE AMERICAN ACADEMY. AURORAS ARRANGED ACCORDING TO YEARS, ZONES, AND HEMISPHERES. Continued. | WOLF’S CATALOGUE. | LOVERING’S CATALOGUE. . 3 Piz o o oD 3 g | 8 | s 3 & | 8B | a = & | 8 joa 1 =! 4 ce 2, : 1 Pi fe =! : * me a oS 3 2/9/98 /)8\/8)4) 2 ig |e) &) 8) 4 ble) ee Ba eee Bc | Sea, gol Go hams eeal ee BS lea | Syke) Vek Ts oy Pee) esi ae ees if 61 . | 64 | 66 | 67.7 || 1781 6 | 64 | 29 86 || 39 39 (100 5 1 | 54} 10) 60 | 60 | 33.2 || 1782 || 3 | 44 | 34 66 || 43 43 | 91 5 2 | 68 | 29 | 85 | 85 | 22.5 || 1783 || 4 | 65 | 22 76 || 29 29 | 90 4 1A 22169) | 169) 4.4 || 1784 || 9 | 32 | 28 65 5 BY | (ay 5 SAD ES2 GT levee ieeks-onl) Lao mcm Or | tea 66 | 16 SW Gy |p 743 10 2 |100 | 73 |121 {140 | 60.8 || 1786 4 |104 |) 82] . 149 || 56 | . S a e2Oull tian: O31 | 11 1102 | 84 1056 \174 | 92:8 || 1787 || 28 (106 |) 73) . |L5L |53 )) . - | 28 | 78 11182: 10 | 13 |114 | 62 |159 |159 | 90.6 || 1788 ||/13 |121 | 63 153 || 41 . A . | 41 1164 3 5 1100 | 69 {140 |140 | 85.4 || 1789 || 4 |101 | 66 |] . {131 || 51 51 1159 5 2|-77 | 63 | 87 | 87} 75.2 || 1790 || . TONG a) vs MELO eS 13 |123 2 . | 76 | 18 | 88 | 88 | 46.1 || 1791 UN) FAO) 23 86°|| 13 13 | 86 2 SS ee ey Gy ESP ONT brES Pa OAS Gi) heel ae hegiih 7 7 | 82 5 PRPS a are ie Oe Lon mene lagna. 17 3 = (20 8 8 | 23 Bi] 2) Bl, 8] wees | 7794: 9} 2 aa eat 1] 12 6 2 6 6 | 16.5 || 1795 | 3 2 D-|\) 2 2 Ff 2 1 2 2 9.4 || 1796 || . 2 1 3 : 5 3 13 a licoa | eli 9.6) || L797 A 14 1 15 : 15 1 1 2 2 AS) LIB | ee 1 1 2 || - al; > 2 5 1 6 6 5.9 || 1799 4 2 Ga} |e 5 6 6 5 6 6 | 10.1 || 1800 | 6 ‘ 6 A 5 6 8 4} 12 | 12 | 30.9 |} 1801 5 4 9 s é 9 2 6 8 8 | 38.3 || 1802 5 if 2 a: 1 | 14 1 1 2 2 50.0 || 1803 7 : TEN & 5 | 10 4 3 4 4} 70.0 || 1804 9 2 10 4 4) 12 1 | 23 2 | 23 | 23} 50.0 |/ 1805 6 2 20 4 4 | 22 1 3 4 4 4} 30.0 || 1806 6 1 7 4 4/11 : 2 P 3 3 | 10.0 || 1807 1 2 6 4 4 6 1 , 1 1 2.2 || 1808 2 1 3 ||) 12 1 \| 115321 F : a 0.8 || 1809 ‘ 1 c 1 2 2 3 1 1 1 0.0 || 1810 : 1 ; 1 2 5 F 2 s 1 1 1 0.9 |} 1811 et all vate , 4 4 - : 4 A 1 1 1 5.4 || 1812 - 5 : : 2 3 : 2 ‘ 2 2! 13.7 || 1813 2 : PHAN Lo F 2 6 1 7 | 84] 20.0 || 1814 7 2 7 \| 4 4 9 2 25 2 21 35.0 || 1815 2 3 5 3 3 5 2 5 5 3?} 45.5 || 1816 2 Aull) 4 1 1 5 11 Z| 1b 120) M4355 Sie 9} 138 22 2 2 | 26 4 5 8 | 18 | 34.1 || 1818 2 om 6 || 18 3 : 5 | ash jsut 9 | 16 | 18 | 47 | 22.5 || 1819 9 2 10 Sy eLOs | Se a6 S| PSone Ay | 2s 8.9 || 1820 2. 20 25 2 46 | 30 | 11 | 86 {1038 ON THE PERIODICITY OF THE AURORA BOREALIS. AURORAS ARRANGED ACCORDING TO YEARS, ZONES, AND HEMISPHERES. Continued. WOLF’S CATALOGUE. LOVERING’S CATALOGUE. o* 4a . 36 o = es is} See |) aS g ts |) ee || a % | B | a i el peste laiecoll ag & ee em adios ieee Pens |( PS colt essai hal fee ea esa aaah rel eka a tall rl a ered aM] If See) Suse es Stl, os Bee thas hs haley Tice He Nie Ve ete Hee re |) ie) ©) alsa |) ZUSy NI sia Sa eA sili 107 | 21107) 135 Pit S| Sl Bel) Be ayy ih | 3} |) is) | 2 II al 71 5) 18) 85 Bi Ole A) Tea ae al di By Bll B Wi A a, i 6] 6] 28] 6.7 || 1824 eae valle Sallie By |) |] alge |) BE 2/95 | 25 | 55| 17.4 || 1825 2 | 20 22 || 2 7/24} 33| 53 9 | 21 | 25 | 64] 29.4 || 1826 5?] 12 13 || 3 43 | 1) 45] 57 2 | 16 | 28 | 34] 61] 39.9 || 1827 20 | 43 58 || 17 BV A |} Sbsll ete 12 | 33 | 39 | 59] 52.5 || 1828 14? 45 53 || 25 roses Gil eeric 20 | 44 | 54 | 97] 53.5 || 1829 23 | 32 53 || 31 4|15| 43] 95 : 28 | 95 1105 |148| 59.1 || 1830 || . | 37 | 36 64 || 87 3] 87|139 Beene MONA Os ess. cullplsstl ||| 3 | 27 87 I S || 4855 5 | 56] 95 . 6 | 6 {| 11] 83] 29.5 || 1832 || . NG |) il) eh Ni ay Sy elelesi mee ; See OM eral web kSS3ei) | 18 i w5 |) 21 25) |) 43 BYE Sl val) oe : 4/ 2] 5/154) 11.4 || 1834 || . 6 | 3] 12] 18 || 42 125 | . |153|158 1 ColuM anavoieedoael| deesasi\| f 4/12] 6] 18 || 32 Ale le eGo aie 1 | 4 | 13 | 12 | 22] 96) 96.7 || 1836 || 1 EN 5 | Ge II ae Silhevooll’ (sill. 355, Delsel 20e e2Se49e OiN| ta One 1S3z |! 2 | ix || 49). |) 609/69 ee ZOOS : 5 | 41 | 44/184] 892.6 || 1838 || . 8 | 42 |107 |125 || 61 4 |) Bill tex! 4 | 2 | 23 | 50 | 63 |190] 68.5 || 1839 || 3 | 12 | 47 1146 |164 || 83 . | 83] 208 14 | 3 | 18 | 48 | 60 |145) 51.8 || 1840 || 4 | 8] 52) 8 | 58 1/106 . | 10 | 110] 144 le Qaleson On Gle ot 297 I 1840 i 3 | 93) 47 63 |112 | . | 60 | 15 |155]174 5 | 1 | 18] 49 | 60/105) 19.5 || 1842 || 1 Hl Gil 68 || 64 | 1] 98 | 15 | 150/178 2 22 | 538 | 62/119] 8.6 || 1843 |] 2 | 9 | 51 61 || 70 103 | 18 |155|172 1 27 | 49 | 61 | 94] 13.0 || 1844 || 1 9 | 49 53 || 50 128 | 12 |165|177 18 | 61 | 71 |118] 33.0 ||.1845 || 1 | 13 | 59 63 || 61 | . | 74] 24 | 126/159 . | 8 | 25-| 58 | 76 |140| 47.0 || 1846 18 | 54 67 || 91 |. | eel 8S ao 69 Bak | BO |) ee Te TOE TY AT ed) Yay atts} 86) || 72a by eel 29 9S: ag 6 | 3 | 40 | 60 | 80 |198} 100.4 || 1848 || 2 | 46 | 65 90 |1153 | 58 | . | 72 | 191) 224 2 | 2.| 24 | 56 |) 64/217) 95.6 || 1849 || . | 32) 57] . | 77 |Ite1 | 71 | 32 | 74 (240) 251 5 10 | 22 | 31 |169] 64.5 || 1850 | 29 | 36 | 1] 58 |1179 | 63 | 63 | 59 | 287] 291 - | 1 | 20] 17] 34) 74] 61.9 || 1851 | 72 |19| 9 | 81 |{144 1118 |.98 | 41 | 319] 319 2 31 | 44 | 63 |126] 52.2 || 1852 85 | 60 | 9 |117 ||160 1160 |254 | 6 | 283/296 ; 20 | 26 | 32 |102| 37.7 || 1853 | 82 | 24] 7 | 89 |l105 | 15 1104 | 10 | 190] 214 2 5 | 86 | 89 | 61] 19.2 || 1854 | 1 | 40 | 12 | 50 || 94 8 | 102] 117 Sal 32 | 23 | 53] 6.9 || 1855 SW ee Ny ay | ee I 2| 74] 90 Sasa Sao ani 36i|) 4.21) 1856 7126! 9 | 40 || 37 sales 7G es Gea Ge ee Piller P.6 |!) LS5 a 3 | 21] 38 | 22 || 35 15 | 48] 59 . Til |) BEF | as I AS) ON TERT Gy I Se Se) a II XO: |] 1B) || TBs) 14 | 3 | 33 | 50 |.70 | 82) 96.4 || 1859'|| 8 | 47 | 64] 12 | 95 || 79 | 11] 18] 17] 94) 136 Te ee OM Ade Sonne 5) 59866 | TS60) I 2) 2maleGll | esha Goel Selina feelin rena MRS Oh itso Cm Snes OH retell LSGI aie tee 25. 1 40) |) 5: el On eerie 71 | 122 ; 59.4 || 1862 || 7 | 14 | 56 78 || 59 ; 67 | 126 44.4 || 1863 || 3 | 12 | 68 80 || 37 3] .1| 49|108 | 47.1 || 1864 || 5 | 29 | 48 72 || 30 3 33| 96 || 1865 || 4 | 34 | 57 85 || 66 F 66 | 124 | | 1866 || 2 | 7 | 39 44 || 41 Alu inuai | |] 1867 | : 18 18| 18 || 1868 | 6 : 6 344 MEMOIRS OF THE AMERICAN ACADEMY. Is it proved, as yet, that years of sun-spots are years of auroras any more satisfac- torily than the theory is proved that years of fire-balls are years of sun-spots, as Ritter suggested,’ or the theory that years of earthquakes are years of auroras? A lesson of caution against hasty conclusions on subjects of such complexity may be drawn from the fact, that whereas Boué? favored the conclusion that the aurora goes hand in hand with the earthquake, and whereas Wolf had decided, though from data afterwards acknowledged to be insufficient, that years rich in sun-spots corresponded to years rich in earthquakes, Kluge,’ from a more searching examination and the use of larger materials, finds a periodicity for earthquakes as long as that which governs the sun- spots and magnetic disturbances, but with maxima and minima reversed. Fritz‘ has recently investigated the periodicity of the aurora in relation to the frequency of lightning, and of the precipitation of rain or snow, and the amount of the fall, and comes to the following conclusion : — “Obige Zusammenstellungen ergeben uns somit das Resultat, dass weder in Bezug auf den Wechsel der jahrlich beobachteten Anzahl Gewitter fiir wenige oder viele iiber die Erde verbreite- ter Orte, noch fiir die in ihnlicher Zusammenstellung untersuchten Mengen von Niederschlagen, sich irgend ein regelmiissiger periodischer Wechsel zu erkennen gibt, am wenigsten ein solcher, welcher in der Weise mit der Hiaufigkeit der Polarlichter harmonirt, dass man auf irgend welche Wechselbeziehung zwischen den ersten beiden Erscheinungen einerseits und den Polarlichtern andrerseits schliessen kénnte. Obige Zusammenstellungen zeigen recht deutlich, wie wenig zulissig Schliisse in der Meteorologie sind, die aus einzelnen Beobachtungen gezogen werden, wie dieses bei der grossen Nordlichtperiode von 1859 beziiglich der vorhergehenden Jahre geschehen.” Some importance has been attached to the supposed resemblance between the solar corona, the zodiacal light, and the aurora, when they are examined through the spec- troscope, as proving an identity of nature in the phenomena. Such an identity, if fully established, would prove nothing more than this: that there existed in the earth’s atmosphere, or in whatever other region of space might be the scene of auroral mani- festations, the same materials as pervaded the luminous atmosphere of the sun. That the sun had any mfluence in setting them on fire, and that there was any connection between their incandescence and the fluctuations in the sun’s light or heat, would require the same proof as ever. Moreover, the observations made on the aurora with the spectroscope utter an uncertain sound. Angstrom finds this spectrum discontinu- ous, whereas Winlock observes in it, at least in that of the eastern and western arch of the aurora, perfect continuity. 1 Gilbert. Annalen der Physik, XVI. 221. 2 Sitzungsberichte der Kais. Acad. der Wissensch. XXII. 435. * Vierteljahrsschrift der Naturforsch. Gesellschaft in Ziirich, IX. 267. * Vierteljahrsschrift der Naturforsch. Gesellschaft in Ziirich, XIII. 369. ON THE PERIODICITY OF THE AURORA BOREALIS. 345 I have failed to discover any connection between the secular changes in the earth’s magnetism and the secu/ar periodicity of the aurora. The comparison is an imperfect one, inasmuch as, in the aurora, it pertains exclusively to the frequency of the dis- plays, without any regard to their magnitude, and, in terrestrial magnetism, it only embraces the single element of declination. . The secular periodicity of the aurora is mainly the same for the whole earth, both as to the length of the period and the times of maxima and minima. This is not the case with the secular changes in the declination of the magnetic needle. Columbus remarked on September 15, 1492, that “21° east of the island of Corvo” (one of the Azores) “the magnetic varia- tion changed and passed from N. E. to N. W.”* Although the line of no variation moved through an angle of 80° in longitude, in the course of one hundred and fifty years, on the parallel of Paris, at the Azores it appears to have been stationary for the long interval between 1492 and 1600.;+ Moreover, the invariability of the decli- nation, for a long period, at Spitzbergen, in New Holland, and among the Antilles, indicates changes in the earth’s magnetism which affect different places very un- equally. On the eastern continents, the needle reached its extreme westerly position about 1800, viz., in 1815 at London, in 1814 at Paris, and in 1791 at the Cape of Good Hope. It was near the extreme easterly limit of its oscillation in 1580 at London, and also at Paris. During this long interval of about two hundred and twenty years, the magnetic meridian of London has swept over an angle of 359°, and that of Paris over an angle of nearly 343°. From the report made to the superintendent of the United States Coast Survey, in 1855, by Mr. Charles A. Schott, { it appears that the minimum westerly declination in the United States of America was, on the aver- age of all the stations discussed, in the year 1798. The maximum westerly variation was about the year 1679. Therefore the minimum westerly declination here occurred at nearly the same time as the maximum westerly in Europe. But the range of motion at the three places which entered into Mr. Schott’s discussion did not exceed 6°. In this particular, a broad distinction is indicated between the’ two hemispheres. The greatest yearly change occurred about 1741, and again about 1850. If we com- pare with these average values the particular ones which Mr. Schott has obtained for individual places, extending over a wide geographical area, we discover differences, * Humboldt’s Cosmos, translated by Otté, I. 174; and II. 657. + Quetelet thinks that, in the time of Aristotle, it may have been 24° east of the meridian of Greenwich, Bull. de l’Acad. Brux., XXI. 303. $ United States Coast Survey Report, 1855, pp. 315, 337. VoL. xX. 44 346 MEMOIRS OF THE AMERICAN ACADEMY. depending upon locality, which seem to have no parallel in the secular periodicity of the aurora.* A secondary period of about eighty-eight years, within the larger one, with a range of only ;; of the value of the principal oscillation, has been indi- cated by a close.scrutiny of the observations made at some stations, but the length, epoch, and range of this subordinate oscillation vary with the locality.+ The best knowledge of the present day, therefore, furnishes no foundation for the inference, that, because terrestrial magnetism undergoes secular changes, and also the frequency in auroral displays, the two classes of phenomena have a parallelism, not to say some connection with each other. Such a connection Ussher} seems to have hinted at many years ago when he calls attention to the fact of a chasm in the auroral records about 1661 for forty years, compared with the years which preceded and followed, and to that other-fact that during this period of vacancy the declination of the mag- netic needle at Paris became zero. The curve of xo variation (or declination) passed through London about 1660, through Paris about 1663, through the Cape of Good Hope between 1605 and 1609. If this event produced any effect whatever upon the recurrence of the aurora, we should expect that effect to antedate by fifty years, at some places, the period of its occurrence at other places. Nothing but negative evidence on this subject can be found. But what we know of the aurora during the last hundred years assures us that the periods of the secular maxima and minima are, to a great degree, independent of geographical locality. If the magnetic poles of the earth are moving, and consequently the magnetic latitudes of places are changing, we can easily imagine that such a change would have some influence on the frequency of auroras. But no motion of the magnetic poles has been discovered, which, in itself or in its effects, conforms, in period, to the well-established secular variations in the aurora. These variations evidently depend upon some cause which operates alike, and nearly simultaneously, over remote continents. De la Rive remarks: “Nous concevons done facilement que le déplacement des glaces polaires, joint 4 celui du pole magnétique de la terre, ait pu déterminer momentanément des conditions peu favorables 4 l’apparition de l’aurore boréale. Une chose assez remarquable, c’est que cette longue période sans aurore boréale coincide avec Yépoque ot laiguille aimantée était exactement dirigée dans le méridien terrestre (année 1662).”§ As equally decided minima in the frequency of auroras occurred in the middle of the last * United States Coast Survey Report, 1859, p. 299. ¢ United States Coast Survey Report, 1858, pp. 193, 194. t Transactions of the Irish Academy, 1788, II. 191. § Traité d’Electricité, IIL. 304. ON THE PERIODICITY OF THE AURORA BOREALIS. 347 century and in the earlier part of the present century (allowance being made for the increased number of observers and the multiplicity of records), without a similar cause existing, another explanation seems to be required for this periodicity. Some connection between the aurora and the indications of the barometer was hinted at many years since by Madison.* Recently, the discussion of long series of barometrical observations, in a particular way, has revealed a period-of fifty-six or sixty years.| But this periodicity will not help us to explain the secular periods of the aurora. Of little avail, also, for this purpose, have proved those secular changes in temperature which the delicate scrutiny of multiplied observations manifests: for example, the oscillation between warm winters and cold winters in a period of about forty-one years, the cold reaching its height in 1830, and again (by prediction) in 1871.5 * Philosophical Transactions of Philadelphia, II. 142. Trans. Irish Academy, II. 71, 72. ¢ Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, VIII. 106. t Wochenschrift fiir Astronomie, Méteorologie, etc., IV. 162. ’ 348 MEMOIRS OF THE AMERICAN ACADEMY. ERRATA ET ADDENDA. Ir was intimated, on page 12, that Mairan had been, probably, led into some mistakes and had duplicated some auroras by reducing again to new style dates which were originally given in new style. The following cases are sufficiently clear. The aurora of .March 17, 1707, is the same as that of March 6. The aurora of December 7, 1710, is the same as that of November 26. The aurora of May 1, 1716, is the same as that of April 20. The auroras of May 2, 3, 4, and 5 should be changed to April 21, 22, 23, and 24. The aurora of March 15, 1718, is the same as that of March 4. . The auroras of March 5 and 6, 1719, are the same as those of February 22 and 23. The aurora of April 9 is the same as that of March 29. The aurora of April 18 is the same as that of April 7. The aurora of October 27 is the same as that of October 16. The aurora of November 14 is the same as that of November 3. The aurora of November 17 is the same as that of November 6. The aurora of November 24 is fhe same as that of November 13. The aurora of December 1 is the same as that of November 20. The auroras of April 10, September 25, October 30, November 22, should be carried back by 11 days. The aurora of February 26, 1720, is the same as that of February 15. The aurora of December 10 is not found in Frobes. The date of September 23?, 1721, should be changed to September 28. Mairan has not altered Frobes’s dates for February, 1721, but all the others for 1721, and all for 1722 and 1723, have been advanced by 11 days, as if they had been given by Frobes in old style. There is no obscurity in the matter after January 1, 1724.* F Is the aurora of January 20, 1728, in Frobes’s work ? The auroras which Frobes and Mairan assign to April 6, 9, 10, and 11, 1717, are probably the same as those of January 6, 9, 10, and 11 of that year. See Mém. de |’Acad. Paris, 1717, p. 3. There are some discrepancies between the dates of auroras given by Dalton in his Meteorological Observa- tions and Essays and his record in the Manchester Memoirs, Vol. V. p. 666, &e. On page 23, for 1757 read 1657. On page 25, note 9, for ZZ. 566 read J 566. On page 26, the aurora which Boué assigns to November 3, 1719, is probably the same as that of November 14. On page 26, I have given the date of December 22, 1719, to the first aurora seen in New England, on the assumption that the date of December 11, as given in the Mass. Coll. and by Felt, is in old style. I should add that Trumbull and Holmes place this aurora on December 17. On page 27, against the aurora at Lynn, for September 23, 1721, read September 28. On page 29, against the auroras at Upsal, for September 6, 9, and 11, 1725, read February 6, 9, and 11. Acta Lit. Sueciz., IT. 141. * For auroras of 1719, see Rozier, Obsery. sur la Physique, XV. 134. ERRATA ET ADDENDA. 349 On page 31, Pilgram’s authority is for March 1, 1728, and not March 2. On page 34, Pilgram’s name should be attached to the observation of September 15, 1729, instead of September 20. On page 35, the aurora for October 23, 1730, recorded by Mairan, is repeated out of its place ; also, against Plymouth, for October 6 read October 8. On page 36 against October 2, 1731, and elsewhere against January 9 and August 22, 1737, April 9, June 2, September 25, 17389, also against April 6, 1741, for Kahn read Kalm. On page 39, for September 2, 1733, read October 2. Thompson’s authority belongs to February 22, 1734, and not to February 23. Strike out November 27 and 29, 1733. On page 49, for June 13, 20, and 27, 1744, read August 13, 20, and 27. It is doubtful whether the aurora at Tubingen of June 13, 1745, may not belong to Jume 13, 1744, and that of January 9, 1746, to January 9, 1745. On page 52, the aurora of January 23, 1750, is probably given in old style. On page 59, add to the aurora of October 28, 1768, the places where it was seen, viz., Rome and Vienna, and the authority, viz., Cotte. On page 61, in the aurora ascribed to Franeker, for December 4 read December 5. On page 66, last line, for February 19 read April 9. On page 67, the aurora given by Cotte for December 6, 1777, is quoted as on December 5 in the Connaiss. de Tems for 1781, p. 390. On page 71, the aurora of November 27, 1779, observed at Gurzelen, should be changed to December 6. In aurora of February 29, 1780, transfer the reference of note 5 from Geneva to Berne. Strike out the aurora of November 16, 1780, at St. Petersburg. . On pages 72, &c., many of the auroras recorded for the years 1781-1792 are extracted from the volumes entitled Zphem. Soc. Meteor. Palat. On page 72, against the aurora at Montmorenci, for April 15, 1781, read April 25. On page 78, against the aurora at Cambridge, by Williams, for October 5, 1785, read October 6. On page 79, against the aurora at Salem, for March 35, 1786, read March 25. On the last line of left column, for 1 read March 1. On page 81, all the observations assigned to September 18, 1786, should be transferred to September 19. The observation at Montmorenci, on May 30, is out of place. On page 87, the query against Sagan should be transferred from April 1, 1788, to April 26. The reference against Cassini on March 28 is incorrectly printed. On page 94, left-hand note, for fur. read fiir. On page 95, the aurora of October 13, 1792, is duplicated at New Haven. On page 96, in note 8, add to Journ. de Physique the volumes, viz., Vol. XLIX. pp. 235 and 301, and succeeding volumes. For the auroras of July 23 and September 3, 1799, refer also to Connaiss. de Tems, 1803, p. 511. ; On page 97, to the observations on October 22, 1804, add the place, viz., Sweden. On page 98, in note 6, for Aurora Phenom., read Auroral Phenom. For the observations made at the Paris Observatory in the years 1803-1805, see Connaiss. de Tems, 1806-1807, p. 498; 1808, p. 498; and 1809, pp. 498, 499. On page 98, against Salem, for Janwary 31, 1814, read February 28. 350 MEMOIRS OF THE AMERICAN ACADEMY. On page 99, add to March 15 and 16, 1817, Baylies’s authority, and for Amer. Journ. Sci., XVI, read Amer. Journ. Sci., XIV. 103. Also, on this page, against Salem, for September 26, 1816, read September 26, 1815. On page 102, against December 19, 1820, for Enterprise read Enterprize. On page 104, in note 4 on right hand, for Annals of Phil. read Phil. Mag. On the same page, in note 7 on left hand, add to the auroras seen at Port Bowen, “two in October, five in November, and seven in December, or forty-seven in all.” Journ. of a Third Voyage, &c., 69. On page 108, for 29 read “29. On page 110, to aurora of September 13, 1830, observed at St. Petersburg, add this reference: Recueil d’ Observ. Magnet. a St. Petersburg, p. 679. On page 110, 113, 116, and 120, in the notes, for Meter, read Meteor. On page 111, against January 7, 1831, for Krankfurt, read Frankfurt. Against December 11, 1830, for Newbery, read Newberry. On page 112, against May 30, 1831, for Burney, read Burney*; and against August 19, for Henry*, read Henry*. On page 113, to the aurora of October 31, 1832, add Kupffer as authority. See Annuaire Magnet. et Météor. de Russie, 1845, Suppl., p. 5. On page 115, note 1, the reference is to August 12, 1836, and not August 12,1834. See Corr. Math. et Physique, X. 178. On page 118, to the observation of October 18, 1836, at St. Petersburg, add the reference: Observ. Meétéor. et Magnet. de Russie, 1836, P.. 170. On page 119, the aurora of September 18, 1837, at Yakoutsk, is not mentioned in the Annuaire Magnet. et Météor. de Russie, 1839, Suppl., p. 423; but only those of September 3 and 11. On the same page, to the aurora of February 18, 1837, at Catherinebourg, add the reference, viz., Annuaire Magnet. et Météor. de Russie, 1837, p. 28. On page 120, against October 18, 1837, for Zlaloouste, read Zlatoouste ; and add page 200 to the note. On the same page, to the observation of October 6, 1837, at St. Petersburg, add the reference: Odserv. Météor. et Magnet. de Russie, 1837, p. 120. On page 123, first line, for January 25, 1839, read January 16. On page 135, the observation at Toronto was on July 7, 1843, instead of July 4. On page 156, against the aurora of February 10, 1850, Noodt’s reference is omitted, viz. Annales de U Observatoire Physique Central de Russie, 1860, Supplément, p. 27. On page’ 164, the observations at Christiania, assigned to January 14, 27, and 28, 1853, belong to February 14, 27, and 28. In note 1, relating to Maguire, for 1823 — 4, read 1853 — 4. On page 171, &c., besides the auroras here given for Athens, luminous appearances were seen there August 2, 7, 8, September 26, 1861, and July 21, 1862, which are described as “phosph. Bégen,” or “ phosph. Streifen.” Wochenschrift fiir Astronomie, Meteorologie, etc., VII. 10. On page 190, there are some trifling errors in the table for Paris, as will appear by examining the catalogues for the years 1787, 1788, and 1794-1799. On page 219, note 5, Report of the British Association, for XXVIII. read XX VII. On page 234, note 2, add the original reference to Secchi’s publication Sul le Var. Per. del Mag. Terr. Estratta dagli Atti del? Accademia Pontificia d’ Nuovi Lincei. Anno VI. Sessime 1%, del 19 December, 1852, p. 56. ERRATA ET ADDENDA. ; 351 On page 243, line 4, for decimal, read decennial. Also, in note 1, to Astronomischen Nachrichten, add Vol. XL VII. p. 286. On page 251, to the two auroras observed at Paris on October 16 and 17, add the year 1795; and for October 16 and 17, read October 17 and 18. On page 255, to the observations at Nova Zembla in 1834 may be appended the following note: Durant tout l’automne pendant les nuits sereines ou peu nuageuses il y avait souvent des aurores. Annuaire Magnet. et Météor. de Russie, 1845, Supplement. On page 258, in note 2 on right hand, to Fortschritte der Physik, add fiir 1847, p. 179. On page 289, it may be remarked in reference to the year 1859, that auroras are mentioned as occurring on February 11, 12, 14, and 18, July 18 (australis), August 2 and 25, and on October 13, which are not in any of my catalogues. Vierteljahrsschrift der Naturforsch. Gesellsch. in Ziirich, V. 239. From 1772, when the new style was used in recording the St. Petersburg observations, as far as page 69, the printed dates of this catalogue are eleven days in advance of the correct dates. In my paper on the Secular Periodicity of the aurora, in Volume IX. p. 120 of these Memoirs, in the record of Dr. Hale’s observations, for June 14 and 19, 1839, read January 14 and 19. Auroras were seen in Upsal, Sweden, on February 18 and 19, September 15, October 16, November 29, 1855. Nova Acta Regie Soc. Scientiarum Upsaliensis, 8. III. Vol. I. p. 257. Auroras were seen by J. W. Lovering, on August 14, in Lat. 54° N., Long. 21° 36’ W.; near the Orkney Islands on August 18 and 19 (the latter feeble); in the Gulf of Finland, near Cronstadt, on October 11 and 12, 1866. Norr.— It should be stated that pages 25 to 200 inclusive were printed previously to January, 1866; pages 201 to 216 inclusive previously to November, 1866; pages 217 to 248 inclusive previously to May, 1867; pages 218 to 304 and pages 1 to 8 inclusive previously to September, 1868; pages 305 to 344 inclusive previously to August, 1870, and pages 345 to end previously to May, 1871. “sBLOINB ZFSL (‘L9-OFS1) “BPLUBD ‘o;MOIOT, svioine 62% (‘zG-8FST) “BpeueD ‘oqon?) ° ° . e ‘ r e ® re * a ! ° . . . . e . . . ° ° . _— ~ ‘snrome Fy (‘E9- 2681) “FA “WOISUTANg ‘snrome egt (‘1¢-OF8I1) ‘puLlueorN “UARYsqoore te ‘seroane giz (‘19-FE81) “IA ‘Attaqaony ° « ° . . : » ° e ‘svioine ogF (‘9F-1F8I1) ‘puBjuseTH ‘queTjoy ‘surorne [¢1 (‘1¢—6FS81) “‘PUB[PUNOJMEN, ° . . e e J e > . ° e . ‘svioIne col (‘FESl) “eoURTAY WOT i=] Zz [) Dn > x a > i ie] a i] w (1 gp > qo uy ed > gZ ty sl oO eo a ee oy ee ins ceo et ere me ee pa Pe GFF E S F ‘Arenuep yy Suyuurseq ‘syjzuou quereyIp oy} UT seIOANW Jo Jequinu oy} yuosetder sean SurmoT[oy ouL The following curves represent the number of Auroras in the different months, beginning with January. | : 4 ; q | 4 s & gos &§ eS / 5 2 5 3 e Sept Oct oY June. Sept. Oct. ov. a 3 a Jan. Feb. Feb. s . Brunswick, Maine, (1807-57,) 108 auroras. es . . e * : 2 P ' Z A é P A aroridenes R. ig, (1832- -60,) 160 auroras. New York State, (1826-50,) 1205 auroras. ’ ° . . . F ° . A . . . e en Salem, Mass., (1786-1820,) 198 auroras. = 2 & 9 a $ g zr Eh F} e a ze 5 ° 2 ? 2 i = i & 3 5 z a S , a quoieyip oy} Uy se1omy jo tequinu 96y} quosoider Sead SupMoOT[OS OULL “Get ‘aer The following curves represent the number of Auroras in the different months, beginning with January. | a : 5 o =| oe cs yey 5 e z cs] = 2 > tb < > 3 5 >I tal =I = to = ety 5 5 E > a 2 B 2 5 3 8 2 3 Es 3 5 a EI 3] 3 E z Z — \ 5 3 < a é Zz A SaeesG = < |r 5 < a 6 Zz a . . . . - : . ° e . . . Plymouth, Engl., (1728-48,) 120 auroras. oo . . . Berlin, (1707-89,) 341 auroras. G. Britain, (1786-1834,) 435 auroras. Mannheim, (1781-92,) 216 auroras. e e s . - = ° e . » . Ratisbon, (1781-91,) 54 auroras Tenn (170- 96,) 84 auroras. . - e e Le . we Wittemberg, (1730-51,) 91 auroras. Sagan, (1781-92,) 240 auroras. Satie (779- 1831 ,) 87 auroras. : ‘svioine [ez (‘ISSI-SLL1) ‘MNIspg ‘sfassn1ig SBIOING QGGE‘I] WoIF y[Nsoy uvoyy ~ a en ‘seoane [ez (‘I8-1LL1) ‘puBl[oR, “1oyour.s ke e e ° . . e . e e . ° ° ‘suloINU gg (‘1¢= LaL1) Ket] . ° ° . - . “seroinv cL (‘GOSI-ILL1) ‘eouvrg ‘ouetomjUO}T . e ° . . . - - ‘soins O06, (‘26-8641) ‘PUrloOH ‘spioine #9% (‘GFSI-OILI) ‘oouvrg ‘seg . e . e . ° . . e ‘stioine gf (‘88-Z8L1) ‘uasvquodop e e e se e Ld . e e . 4 = q a > 4 I a =] zw ° na > q a > Meee GE ie ee he Ee OEE ‘Aqenuep qm SuTuurseq ‘syyuou quezeytp oq} Ul seiomMY jo 1equINU oT} quoseidert SOAINO SUTMOTIOS SOUL “qoreyl “Qt ‘uep 1750 Suns Spots 1 7 20, St Petersburg 1760 (1770 1780 Lip Salem 1800 America e: 10 Total 1820 1830 1840 1850 ie | wa .. ae Hees Abo. | | | . | JN | | mat | % EE, | Cambridge | / . eas ae aes PES A. Ys y \ Sie WN Soha: OB “he == i” New Haven = | Europe mh | | \ 4 oe aw / = | \ | Yo O eS % Ds N. Pee A SAN Ae : es rib : [ il ai : ai America / \ meee \ ee a eh k I A A \ \ | \ _—_ / \ | / — We rae Vi \ p | A uey) ae ee \ we WS oe \/ \ 20 ae eee [| ' ay | L be aT Total | / N | A / \ \ | ee /\ / V a \ (Gis ay 1 ae ae / ea eS x f mre Sef 1 y Yoo - \ = —$——}— eel a } a ee | | | | i] { | _t ce ed he | | / : {| | A \ | tel | | ea | ih 7 ae ne eh aan ae a es ipa : | we Ocsl O6LI | | < 8 | | | Stes rye = } ee ~ yh f a ae | - Ze \ \ a | — 1. —— stb ry ee : ay sf ‘ NY OFSI O8SLL ( | = © , wS | \ . s SS =< = = : ) / ate ; vy ( < : ~ > | OLLI / | ae | OCSI = \ \ OSL. = 3 / \ > ¢ 5 SS ——_—— \ Ss > \ } ( — < —— a OP LT America urope eS America = i+ At. a MEMOIRS AMERICAN ACADEMY ARTS AND SCIENCES. NEW SERIES. VOL. X.=— PART ik CAMBRIDGE: JOHN WILSON AND SON. University Jress. 1882. my ! oe r i af iE z Sed Ata we 1 } i ay i.% ? Lard MEMOTRS OF THE AMERICAN ACADEMY OF ARTS AND SCIENCES. NEW SERIES. NO EeeX = PAR ITE CAMBRIDGE: JOHN WILSON AND SON. Gniversity Press. 1882. CONTIN ES OF PART At: PAGE III. Discovery of Paleolithic Flint Implements in Upper Egypt. By Henry W. HAYNES . : : : ; ; : : ; : » Sof IV. General Properties of certain Partial Differential Equations similar to those of Hydrodynamics. By Tuomas Craic . : : : : . 862 V. A Comparison of the Harvard College Observatory Catalogue of Stars for 1875.0 with the Fundamental Systems of Auwers, Safford, Boss, and Newcomb. By WiuutAmM A. RoGERS : : : : : : : : . 3889 OFFICERS OF THE ACADEMY. 1881-82. me JOSEPH LOVERING, President. Outver W. Homes, Vice-President. JostsH P. Cooke, Corresponding Secretary. JouN Trowsripce, Lecording Secretary. THEODORE LyMAN, Treasurer. SAMUEL H. ScuppER, Librarian. Council. Class I. Class IT. Class III. CHARLES W. ELIorT, Henry P. BowpiTcH, EDWARD ATKINSON, Wo.cotr GIsss, GEORGE L. GOODALE, FrANcIS J. CHILD, Epwarp C. PICKERING. Henry W. WILLIAMS. CHARLES G. LORING. Rumford Committee. GEORGE B. CLARK, Wo.Lcotr GIBBS, Epwarp C. PICKERING, JostaH P. COOKE, JOSEPH LOVERING, JOHN TROWBRIDGE. Joun M. Orpway, Committee on Publications. ALEXANDER AGASSIZ, Wituram W. Goopwiy, JOHN TROWBRIDGE. Committee on Library. Henry P. BowbDitcu, WILLIAM R. NICHOLS, EpWArD C, PICKERING. Committee on Finance. Ex Officio. By Election. JOSEPH LOVERING, Tuomas T. Bouve. THEODORE LYMAN. Auditing Committee. Henry G. DENNY, Rospert W. Hooper. Til. Discovery of Paleolithic Flint Implements in Upper Egypt. BY PROF. HENRY W. HAYNES. Presented January 12, 1881. Henry Bruescu, in the last edition of his “ History of Egypt under the Pha- raohs,” which has appeared during the present year, asserts that “Egypt throws scorn upon the assumed periods of the three ages of stone, of bronze, and of iron.” ! So also the late Aug. Mariette,” the successful explorer of the antiquities of Egypt, and M. Chabas,? one of the most eminent of their interpreters, while admitting that flints bearing evident traces of human workmanship have been found in that country, alike deny that such objects must necessarily be assigned to a very remote period, claiming that stone implements were used by its inhabitants during historic times. Lepsius,’ the most eminent living Egyptologist, even goes so far as to refuse to allow the human origin of the numerous broken flints found in that country, main- taining that they have been produced solely by natural causes. These eminent authorities have persisted in their incredulity, notwithstanding the fact that M. Ar- celin,> so far back as February, 1869, had announced that he had discovered in the Nile Valley flint implements resembling those found in Western Europe ; and later in the same year Dr. Hamy® and M. Lenormant, and subsequently the Abbé Richard,’ had reported similar discoveries in the same region. Sir John Lubbock,’ also, who had made a journey to Egypt in 1873, for the purpose of forming an independent judg- 1 History of Egypt, chap. iii. 2 Notice des Prin. Mon. du Musée & Boulaq, p. 81. Matériaux pour l’Hist. Prim. — et Nat. de ! Homme, Vol. IX. p. 17, and Vol. XIV. p. 43. 8 Etudes sur l’Ant. Hist. d’Aprés les Sources Egypt., pp. 330, 337. 4 Matériaux, Vol. IX. p. 16. Zeitschrift f. Aegypt. Sprache & Alt. 1870, pp. 89, 113. 5 Matériaux, Vol. V. p. 136. L’Industrie Prim. en Egypte, Rapp. au Min. d’Instruction, Juin 26, 1869. 6 Matériaux, Vol. VI. p. 27. 7 Tbid., p. 248, 8 Jour. of the Anthrop. Inst. of Great Britain, Vol. IV. p. 215. WOlbG 46 358 DISCOVERY OF PALEOLITHIC FLINT IMPLEMENTS IN UPPER EGYPT. ment upon the question after inspecting the localities, had been even more successful than his predecessors, and had published an account of his discoveries in that country, illustrated by several plates, one of which represents three implements that may fairly be regarded as of the palzolithic type. There has been a good deal of discussion in several scientific bodies in regard to the legitimate conclusions to be drawn from these different discoveries, with the gen- eral result, that, owing to the comparatively limited number and extent of such finds, the existence in Egypt of the “stone age,” and especially of the palzolithic age, has either been absolutely denied, or the question has been considered as a still unsettled problem. This circumstance has been much dwelt upon by the opponents of the belief in “the antiquity of man,” who ask for an explanation of how it happens that the “stone age” should fail to make its appearance in the oldest country, in regard to which we possess direct historic information.’ In this condition of the question, I determined to take advantage of a visit to Egypt, in the winter of 1877-78, to make a thorough investigation of the subject. It was my good fortune soon to discover an atelier of worked flints in the desert a few miles east of Cairo, not far from the Red Mountain, on the road to the “ Petrified Forest.” Here I found a few examples of axes of the St. Acheul type, made from water-worn flint pebbles, still retaining some portion of their original surface. Flint does not occur zz sifu in this locality. From this station I also secured quite a number of scrapers, lance-heads, knives, etc. Afterwards I made several visits to the hot sulphur springs at Helouan, in the desert, on the east bank of the Nile, about fifteen miles south of Cairo. In this place, Dr. Reil, the director of the bathing establishment here situated, had discovered, in 1872, numerous worked flints, generally of minute size and of quite peculiar types. Dr. Jukes Brown, in the winter of 1877, also discovered similar objects here, which he described and figured in a communication to the Anthropological Institute on May 18, 1878.2 At this place I, too, was fortunate enough to find numerous specimens of the same types, which have been regarded as almost peculiar to this locality, since they had never been met with elsewhere, with the exception of a few similar ones discovered by M. Riviére in the caves of Mentone, in the south of France. Some weeks later I went up the Nile, and as a hotel had just been opened for the first time at Luxor, the site of ancient Thebes, “ of the hundred gates,” I was able to remain in that locality more than six weeks. This gave me the opportunity of making 1 Southall, The Recent Origin of Man, pp. 20, 31. The Epoch of the Mammouth, p. 4. 2 Jour. of the Anthrop. Inst., Vol. VII. p. 396. DISCOVERY OF PALHOLITHIC FLINT IMPLEMENTS IN UPPER EGYPT. 399 much more careful and extended search for prehistoric remains than had been enjoyed by any who had previously looked for them. I searched the region thoroughly on both sides of the Nile, for distances as great as it was possible to cover in journeys of one day’s length. The valley here is bounded on each side by hills of tertiary lime- stone, filled with layers of flint, on the flanks of which the present surface soil rests without any intervening pleistocene deposits. On the western side these hills are pierced by numerous dry ravines, or wadys, through which the sands of the Libyan Desert make their way down towards-the cultivable strip of alluvial soil on the bank of the river. Although Upper Egypt is a rainless region, still occasionally — perhaps once in twenty years — heavy rains occur, and great torrents tear their way down these wadys into the Nile. In the bottom of such ravines, and sometimes on the summits of the elevated plateaux of the hills, after long-continued and most laborious search- ing, I was rewarded by finding several specimens of palxolithic axes of the true St. Acheul type. I found, besides, immumerable examples of all the different objects that are commonly met with in other countries in which the existence of the “ stone age” is regarded as established. Such were nuclei, disks, scrapers, piercers, lance-heads, arrow-points, knives, flakes, etc., together with some forms that were quite novel. All these, without exception, had been fabricated by the process of chipping. I have, indeed, seen polished stone implements that had been discovered in Egypt, but I have never myself found a single one there. Quite a number of objects were met with in the desert, on the east bank of the river; but the valley on this side is so much wider, that I was not able to reach the hills in one day and have sufficient time left for searching. Pleistocene deposits do not occur in the Nile Valley, so far as I am aware, although they are reported to exist in various parts of the adjacent desert of the Sahara. Quite recently, fine specimens of quartzite implements of the St. Acheul type have been placed in the Museum of St. Germain, which were brought back by M. Rabourdin, who came upon not less than eighteen sites of the manufacture of stone implements in the course of his explorations of the Sahara. But in the valley of the Nile it is only in such spots as those in which I obtained these implements that we can hope to find now any relics of the “stone age.” Most traces of early man in Egypt must necessarily, at the present time, lie buried under hundreds of feet of Nile mud, the accumulation of the annual inundations of the river for count- less ages. The first notice of my discovery was contained in a note to the article, already referred to, by Dr. Jukes Brown in the “ Journal of the Anthropological Institute” for May, 1878. His information was obtained from a gentleman who had seen my 360 DISCOVERY OF PALHOLITHIC FLINT IMPLEMENTS IN UPPER EGYPT. collection at Luxor. The objects themselves I brought to Paris, and at the request of M. de Mortillet, who had charge of the anthropological department of the great French Exposition of that year, I placed a selection from them on exhibition there, for which a medal and a diploma were awarded to me? I also presented some of them at the meeting of the Société d’Anthropologie de Paris, held on October 10, 1878, at which time I gave a brief statement of the circumstances under which they were found’ M. de Mortillet has since spoken of my discovery in an article in the “Revue d’Anthropologie,”® copied into the “ Matériaux,’ * and translated for the “ Popular Science Monthly ” for April, 1879. I have myself also referred to it in an article upon “The Fossil Man,” in the “ Popular Science Monthly” of last July, but hitherto I have not published any designs of the objects. The late Dr. F. Mook, whom I guided to a locality where he found certain imple- ments, has recently published a work, illustrated by several plates, in which he makes the statement that I “ have no objects differing from those figured by him;”’® but it will be seen upon comparison that this is not the case. May not the discovery of this large quantity of flint implements, including several of the most ancient type known, of which some threescore select specimens are here delineated, be fairly claimed to have settled the vexed question of the existence of the “stone age”’ in Egypt? 1 Catalogue Spéc. des Sciences Anthrop., p. 80. ? Bulletin de la Soc. d’Anthrop., Trois. Sér., T. III., Juill. 1878, p. 389. 3 Sec. Sér., Vol. II., Jan. 1879, p. 115. # Vol. XIV. p. 44. 5 Aegyptens Vormetallische Zeit yon F. Mook, Wiirzburg, 1880, p. 27. “ ~~ a> Pintle + . ‘ PLATE 6 Fig. Fig. Fig. Nore DISCOVERY OF PALHOLITHIC FLINT IMPLEMENTS IN UPPER EGYPT. DESCRIPTION All the objects are represented of their natural size. PLATE I. Axe, type of St. Acheul. left bank of the Nile. Same (broken). Same locality. Same. Showing at the top the natural surface of the pebble from which it was made. Vicinity of the “Red Mountain,” near Cairo. Disk. Luxor. Left bank. Same. Showing the natural surface of the pebble from which it was made. Same locality. Luxor. Desert on the PLATE II. Axe, type of St. Acheul. left bank of the Nile. Luxor. Desert on the Same. Same locality. Same. Luxor. From the plateau overlooking the “‘Tombs of the Kings.” Same. Luxor. Left bank. Same. Same locality. Same. Showing at the top the natural surface of the pebble from which it was made. Same local- ity. PLATE III. Rectangular Chopper, novel type. Luxor. Desert on the left bank of the Nile. Triangular axe, type of St. Acheul. Same locality. Axe, type of St. Acheul. Same locality. Hatchet, very rude, merely chipped pebble. Vicin- ity of the ‘‘ Red Mountain,” near Cairo. Same. Same locality. Axe, type of St. Acheul. Luxor. Left bank. Oval axe, type of St. Acheul. Same locality. PLATE IV. Knife, resembling specimens in the museums of Turin, Leyden, and the Historical Society of New York. Supposed to have been used in embalming. Luxor. Desert on the left bank of the Nile. Lance-head, type of Le Moustier. of the Kings. Knife. Luxor. Left bank. Same. Same locality. Axe, type of St. Acheul. Same locality, Knife. Same locality. Chopper, type of Le Moustier. Luxor. of the Temple of Medinet Aboo. Luxor. Tombs Vicinity Fig. Tig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. i=] Fig. Fig. Fig. Fig. Fig. Fig. Fig. c=) Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 361 OF THE PLATES. PLATE V. 1. Rectangular hatchet, novel type. Luxor. Desert on the left bank of the Nile. 2. Hatchet, with cutting edge produced by a series of lateral blows, novel type. Same locality. 3. Axe, type of St. Acheul. Same locality. 4. Oval axe, type of St. Acheul. Same locality. 5. Same. Same locality. 6. Novel object, use unknown. Same locality. 7. Lance-head (beautifully worked). Same locality. 8. Lance-head, different shape. Same locality. 9. Shoe-shaped scraper. Same locality. 10. Small hatchet, edge produced in same manner as in Fig. 2. Luxor. Vicinity of the Rameseum. 11. Hatchet or knife. Luxor. Left bank. 12. Same. Same locality. PLATE VI. 1. Chopper, type of Le Moustier. Luxor. Desert on the left bank of the Nile. 2. Scraper. Same locality. 3. Same. Same locality. 4, Lance-head, type of Le Moustier. Same locality. 5. Hatchet (the broken edge-portion). Vicinity of the **Red Mountain,” near Cairo. . 6. Scraper (7). Novel type. Luxor. Left bank. 7. Hatchet. Same locality. . 8. Chopper, type of Le Moustier. Same locality. . 9. Triangular hatchet. Same locality. 0. Nucleus. Same locality. 1. Same. Vicinity of the ‘‘Red Mountain,” near Cairo. PLATE VII. 1. Arrow-head. Luxor. Desert on the right bank of the Nile. 2. Same (broken). Same locality. 3. Same. Same locality. 4, Same. Same locality. 5. Flake, with hollow probably produced by rounding arrow-shafts. Same locality. 6. Scraper. Luxor, Left bank. 7. Same. Vicinity of the ‘‘Red Mountain,” near Cairo. 8. Same. Luxor. Left bank. 9. Hatchet. Same locality. 10. Same. Helouan. 11. Nucleus. Same locality. - 12. Same. Same locality. 13. Same. Luxor. Left bank. Ve General Properties of certain Partial Differential Equations similar to those of Hydrodynamics. BY THOMAS CRAIG, Pu. D. U. S. Coast and Geodetic Survey, and Johns Hopkins University. Presented January 12, 1881. Tue following investigation was suggested by certain results which I obtained in a previous paper entitled “ General Properties of the Equations of Steady Motion ” which has been published by the United States Coast Survey. It was my intention in that paper to study steady motion only, but as I went on with the work, I per- ceived that many of the results were applicable to fluid motion in general, and that the whole subject admitted of a generalization which would present a number of interesting points. In Vol. LIV. of “Crelle’s Journal” there is a paper by Clebsch entitled “Uber eine allgemeine Transformation der hydrodynamischen Gileichungen,” from which I have taken the proofs of two properties of a certain determinant; the proofs are also to be found in Baltzer’s treatise and in Scott’s treatise on determinants. I did not see Clebsch’s paper until I had nearly completed mine, or I could have omitted one or two tedious processes that I have given by merely referring to Clebsch’s article for the required demonstrations. It will perhaps be better, however, to leave this paper as it is, both because it is simpler and because the two papers are so unlike in their aims and methods of development, that, in order to merely refer to the article by Clebsch, it would be necessary for me to change my article throughout. Clebsch has in view merély a general transformation of the equations of hydrodynamics, while I have in view a general investigation of the “higher orders of motion”’ (vide Note at end) and of the properties of a certain set of Partial Differential Equations of the first order. The present paper is divided into two parts, of which Part I. is herewith com- municated to the Academy; Part II. is not yet completed. In Part IL. it is my GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS, ETC. 863 intention to generalize somewhat the methods and results of Part I. to make an application to the general theory of steady motion ( variables), and finally to apply all of the results of both parts to space of three dimensions, i.e. to the ordinary theory of hydrodynamics. (Just here I wish to call attention to the Note at the end of this paper; it properly belongs in Part II., but as I wish it made public at the earliest opportunity, 1 have inserted it in Part I.) In Part I. an account is given of a set of partial differential equations similar to those of hydrodynamics, but containing x + 1 independent variables, or, if we may use the expression, the equations of fluid motion for space of x dimensions. Denote by 2, %%, #3,....,, ¢ the independent variables of the problem; by WU, U2, -. ++ %, U, certain functions of these variables. For a problem in hydrody- namics the function U is given by v= r+ f>, (1) V being the potential of external forces. The functions wu are similar to the velocities in such an ordinary problem. Write 2g=uptust+....tu?2 (2) then dq diy, duty du, dx, — “dn, + Ua de, + - Fe gee (3) Assume further _ du duty _ du, dus 50 ae eens oss ge oan die etc., 1 and generally du; du fn aaa (4) There will be of course n(n — 1) of these quantities. The functions w are supposed to be connected by the relation du, dug du, Panes. S20 The eat oO: (5) Denoting now the operator d? ad? d? ga gas Sc) Cae 1 gas by v, we have, on observing that €, = — &,, 364 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS dé, , dé, : dé,,, Bt ae laces ea =u dé, bog denn ie of Be, ne cage oe We (6) dé, dns tego = dx, == dit a Sm eae == dx — Vin Between the three quantities €n, Gn, €uv there exists for all values of J, m, n the relation dEmn denn Em ee dx, Ay, dt, 0. (7) This relation holds throughout the three-dimensional space determined by the direc- tions 2, %,, %,; and as these are perfectly arbitrary, it is clear that a like relation holds in each of the Euclidean spaces determined by the directions « taken in groups of three. There does not appear to be any simple expression of this form connecting all of the &functions. Consider for a moment the differential expression Uj, + Uelty + .s. » F Ugh, 5 (a) the conditions that this shall be an exact differential are &, = &3; =....= & »1 = 0; or, as these may all be written, d d d | aaa lass te abe | If this quantity is an exact differential, say d¢, the function ¢ must by virtue of (5) satisfy the differential equation Vo = 0. If (a) can be made an exact differential by choosing a proper integrating factor, we must have 7 UE jr ae U5 Ebi -+- UE: = 0 (9) for all values of i, 7, &; or, as these may be written, Mas Angi x oats sin, died d | tee ia * de, || = (10) Abin (la nuens sone ten SIMILAR TO THOSE OF HYDRODYNAMICS. 365 In a paper by Professor H. W. Lloyd Tanner “On the Transformation of a Linear Differential Expression,’ contained in the Quarterly Journal of Mathematics for December, 1878, it is proved that Uh he Ulta =e = ee te ee is reducible to the form dv, + wodv, + wdv3 +....+ w,de,, (B) if, and only if, d d d | dt,? da, dit, letege cele Un . | =0, (11) 15 d d ae dap a 2 aa | [* dees Pe thasy, sense. teat where there are 27 rows; and that the same quantity is reducible to the form w,dv, + w.dv, + ....+ w,dv,, if, and only if, ak) een! Sr oraseewent) =r d d d | Oe SO) tO so, Bo Nee = 0, (12) d d d | (anid (alin = Sah hpe Wis) Allan ea ei where there are 27 + 1 rows. In both of these cases the functions w and v, though functions of 7, %,....,, are not mutually dependent. In the case in hand it will be shown that the expression (a) can always be reduced to the form (8) when r =x + 1. The case when w,dx, + udx, +....+ ude, is an exact differential dé gives for ¢, as already remarked, ad , dd ap dae aes eat dz,i — 0. (13) I will give here, for convenience of reference, the transformation of this equation in polar codrdinates. Some of the properties of the function ¢ will be found in another part of the paper. Denote by 7, a,, az,....a,_, the polar codrdinates of a point in space of z dimensions. Then write VOT xX. 47 366 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS Ty — ass a5 Y= 7 SIN ay COS ay, £3 = 7 SiN ay Sin ay COS ag, (14) x; =7 sin a, Sin a,.... sin a;_, COs a; Z,—= 7 sa, SiNa,.... SiN a,_}. From these we have P(e ae eae pad x E coal a/ 7? —2 2 cos a, =~, ee COS az = SSS sm a, = a Alo Se aes a 2) 4 Vr—a2? ws : r — (2,7 + 2s? + 27) COS a3 = = 2 An. See ee Vr — (x, + 24") ; Vr — (x7 + 22) : (15) z; : 4 tek a tied Fe ane a a sf FIA ee: YF ae Ly tan Qn —1 ee . . . . e Now we have at once (writing for the moment a, =r) day ie) da, ae day da, day day Ve= ee 32 =a a da? ~ (3 Sh “a grr dx, day, +2 i Pare dz, Eee s Pith d dd. = da, V% Tt a, Vi Vat... (16) The summations in this formula are for all values of & from 1 to i. By performing the necessary operations we find quite readily da, \? da, da, \? i > = = > 2 \ a a) 1, ~ (= \=s se i ao” sin? a,? da; \? F as a 9 : = (&) a,7II a? J 1, ae 1, SIMILAR TO THOSE OF HYDRODYNAMICS. 367 ee FED => = 9 — k de, dx. 0, a 0, i Speen 7 ig oe deat) ds 2 (n»—8) cosag ae ee Va ec V % ~ 4? sin ag sin? ay? 2 [zn — (i+ 1)] cosa; ms WG = Se et ee Von—1 = 0. sing; IL sin? a; Sa Substituting in y’¢, replacing a) by 7, and multiplying through by 7° we have Pd ad 1 @&d 1 ad 1 Id 2 — = SSS = SS {= Se A p au dr” da? tr sin? @ des” aL aa of J =e da? = ste AS day 2 TI sin? a; Il sine; j=l j=l d dd (n—2) cos « dd (n—38) costs db [n—(i+1)] cosa; +r2(n—-) +S 1 sin @ da: a age da, a dea, s 1 2 2 1 ae; sing; I sina; j= cee (16) or, arranging a little differently, d? (7) eee é dd 1 d 2 dp [* dr* a sin @ da ( sin ay qa, ) a8 sin @. sin? a de, Se dts cies Ay 1 d ads 1 ach A are STs Ta ( sin a; ae ) Aes PU ig = pee ; sing, IL sin*a; . 0 sin’a = j=1 = = dd cos &% dp COS Hy 1 dd == [ (n = 3) Beara tz (n 3) sin & da, si (n i 4) Sin @ * sin?@ daz 3 COS &; 1 dd COS Gy, _ 9 1 dd i = Se Feces ==> : =0. (17 + [7 (a +2 J sin a 2 a sin? a da; on ae Fh sin? = ane ( ) j=1 jeu Z Denote by 7 the region of all values of a, 22... . %, for which a2 et ae = (18) i.e. R is the superior limit of 7, Denote by S the boundary of 7’; then S signifies the totality of all systems of values for which yeah iis or ee eg (19) The equation y24 = 0 holds throughout the entire region 7 and right up to the boundary S. Then it can be proved just as in the case of three variables that there is one and only one real function ¢ of the variables x, that for the whole region 7'is single valued and continuous, and at the boundary S coincides with an arbitrary function spread out continuously over S. The first and second differential coefficients 368 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS of @ will be continuous, and the latter will satisfy the equation y*¢ = 0. Denote by dT the element of the region 7’; then dT = daydlxyilty.... d= r"-) (TE sin a day) db"— "dr. (20) k=1 k The element of the boundary S is dS, and this is readily found to be given by dS = R*-1 ("TE sin’ a’ dat) don _y (21) k=1 k (R, a1, a'2,...-a@,_1 being the limits of 7, a, ag, .... an—1) Introducing now an angle 6 defined by | c=n—1 n— cos § = cos a cos ay + = {cos Oy COS ab +1 ‘TI sin a sin aj} + J sina, sina, (22) The introduction of this angle 6 enables us to obtain quite easily ee 5G) Ae (23) n—1R (R? + 7? — 2 Rr cos 8)? ¢, denoting the arbitrarily chosen surface value of ¢. Further consideration of this function ¢ will be deferred for the present, as a full investigation of its properties would require the development of the theory of spherical harmonics for a space of x dimensions. Equation (17) will afford the means of obtaining some of the more elementary of these properties. We will resume here the consideration of the quantities €;. Observe that if we denote the quantities of the left-hand sides of equations (6) by a single letter, say by Ms 72,---. that we have identically dno an, dz, ages Petey =i) (24) If now from the 7’s we form quantities similar to the €’s and call them €}), €).... we shall have a set of equations of the same form as (6) with € replaced by €® and u replaced by ». Calling the left-hand members of this new set 7’, y},...., and again performing the same operations, we get equations similar to (6) with the € replaced by €®, and for the right-hand members y**u, V7??%, etc., where y** means that the operation vy? has been performed twice. This process can of course go on indefinitely or until we come to such values of the y-functions that ny?day + 2 late + . in ndx; is an exact differential. Instead of treating these functions w,, w....w; altogether SIMILAR TO THOSE OF HYDRODYNAMICS. 369 we may consider them combined in groups of three each; i.e. consider the motion in n(n — 1) (n — 2) ——— flat spaces of three dimensions instead of the motion in one space of n dimensions. Equation (7) shows the relation that exists between the rotation components €; in such a space; of course this relation holds for all of the Euclidean spaces which can be formed from the space of x dimensions, and therefore a similar relation exists for the n-dimensional space formed by suming the expression on the left-hand side of (7) for all values of 7, m,n. Write for brevity n (n — 1) (n — 2) 6 ee If the motion in any one of the J three dimensional spaces is rotational, it is of course rotational for the space of n dimensions. For the space containing 2, %, 2%, we have dE, deny d e Ch , Chie =3, = aoe ss Vein dx, dxy, dx, \dx, ' dx, ' da, dEnn diy _ d_ f(dn dn, | any, > Tes ES a (ue econ a) — Vin > (25) dE En d G ae Un, i: Za e a = aa V U1 dx, dim da, \ dx, da, dx, where 7” is written for a d dx? as d? dam ar dx, ~m For ordinary space the quantities in parentheses vanish and these reduce to well- known forms. Write them in the forms 0 = dx, vu Nm = dep V7 tn (26) Nn =F = V Un Form now the quantities TPs din Im Tt = dz, dap Nm = ete. (27) These operations cause the quantity to disappear and leave us 370 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS = VS Sa Vent (28) [See RS LA Perform the same operations on the 7’ functions, and call the results 7, 77%, 7. Tt — , dk 9 9 EES Tey oN ee ie dR tm = V dz Vm (29) Gite less dR Nn V dx, yay, This operation can be carried on indefinitely, and we shall have in each case of an » with an odd number of accents that the quantity 2, or the expansion, as we may call it, disappears, while for the y’s with an even number of accents it appears in the form op UR dx k being here an odd number equal to the number of accents diminished by unity. For an incompressible fluid we have therefore a set of very simple formulas giving the relations between these various orders of motion. We shall now introduce the equations of motion ; these are dU _ du du du du _— ap he Te, + te en da dx, dz, dU _ S Uy dity duy dity im et, th Te, == 1% Te + + wp, Tas (30) dU _ du, du, Ln du, ale Be ea oa Opiate dz, da, i dx, Introducing the quantities € and qg and writing U — q = W, these equations may be written dw x “dz, e eae Up Eig 1 tg fag 1 * 1 Un Sin aw Ty de, dt — t Ga + ts 3 + °° tn Son (31) adW — So ema tli] n—1,n° os — hein Uz Eon — SIMILAR TO THOSE OF HYDRODYNAMICS. ual du For steady motion the terms >, vanish, and then multiplying these equations by Uy, Ug». - U, respectively and adding, we have dW dw dw “Te Uke gine tk 2 cll Oporees = 0 (32) ty day, Equations (51) may be written in the form Ce Me 9 dx; wy dt mle (33) Then, by taking equation (5) into account, we have for the determination of W k=n dz =) Wes a (34) k=1 Take now any two of equations (10), say those indicated by the subscripts 7 and k ; differentiate the j-equation for #, and the k-equation for x, and subtract the second result from the first; continue the process until all of equations (10) have been com- Z 5 A A n(n—1) A bined two at a time by this process; we thus arrive at a group of —4— equations of the form dbs dé dé dé “dt ar ey dx, + Uy 2 day ae ee Un diy, Lis dus dus dit, du, + fa (i ee teas Gn agp 3 ee duty cee TM, och £53 dx, == bee Fe de © & n dx, or generally de, “ik é du; dut;, “dt + ty day F ty ae Siena ale’ oe ee Ge ee a zs) diy da du, + Ex dix; a fou dx; ios als En dx; (35) diy Aity du, SS FG Ci he = cis te 0 Since & = &, = 0 and & = — &,, we may write this equation in the form tke En Ein En — Sm) haa T Us == by GE > | du, du, || = 0 (36) r— 1) day dx; These equations give the vortex motion in the n-dimensional space; for n = 3, they obviously become the ordinary equations for vortex motion. 372 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS The equations giving the motion of a fluid particle are, of course, dx. diy dx. G4 Gm GE = Un (37) Writing for brevity D d d d d 7 Teale Mee ee br ci i ee equations (30) become dU Dy aU Du. ) de, = ae de ee (38) Multiplying these by da, ,dxz... and adding, we have readily Dey dU + dq = | (mda, + uyday + °° * Undaty). (39) Integrating from a point a to another 8, we have 2 SE (ude + Udit, +*** u,dx,) = [U + q]f. (40) If a coincide with £, i.e. if we integrate around a closed curve, = finde, ot tytlas <0, aa, | — 0, (41) a theorem corresponding to that in hydrodynamics which states that the circulation in any closed curve moving with the fluid is independent of the time. As the principal object of this paper is to carry on and generalize the investigations begun in the paper on steady motion previously referred to, I shall leave for the present any further examination of the properties of the quantities dealt with so far and begin from a rather more general point of view. In steady motion a certain Jacobian ap- peared which entered into all of the work in a curious manner, this Jacobian was found from the functions 0,, 62, 3, i.e. | dé, de, db, da? dy’ dz dM, db, Ws de? dy” dz dé, dé, ds da” dy” dz | i (42) In the present more general problem we may introduce a set of functions en ilitieig 5, 0 ean SIMILAR TO THOSE OF HYDRODYNAMICS. Bie of %,%....2%,,¢, denote the Jacobian of these by J, i.e. do dd do ie en ai meee db, dd, dd, i (43) ea ler hind Sense dx; ax, dx, dO, 1 d0,, 1 dO, _ posers dx, dy dz, The minors corresponding to elements in the first row may be denoted by . Aig >) Ana gos atenn Aias and in general for the minors to the elements in the 7 row Aj, ? Ap, OO OOF) Aj. Of course we have now es d0;_ 1 dO; cn} do, =I i Ai da, + Ais diy == oe ee == A,, dx, . (44) The minors A satisfy identically the equations dA, , dAjs GA, __ dx, dat, ste eae E a Ge, 0, ete. (45) If we substitute A, Ay.... Ay, for wm, w....u, in equations (38) we obtain at once ae Ane i= > a Oe (46) ji or ‘ sae Ay k=n j=n dA; NO » He dt; + = 2 Au eee (47) Introducing the quantity 2 q which is now A Ata ate ate Ain (47) becomes I=" GA IU ie a d(U-—q)= > dyt+ > > Ax) || ae. (48) =i b= j= 21 Aj; Ai; For brevity write k=n | a is Ki = A, ee (49) ae Aj, Aj; Assume a set of functions nm — 1 in number Bir Dae eee a Vlg 3% 48 374 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS and write do d, dB, Ky = Og, Oa ge ci pt da, ? = d6. dé. dO, Ye prin Corre og oe st (50) : db, dB, dO, Kia, © Olga . a ee 5 Multiply each of these equations by Ay, Ay,....-A;, respectively and add: this gives A, Ki + 4,kK,+....+4,, 4 =0 (51) a necessary condition, as is easily seen; for if we multiply each XA as given in (49) by the minor A having the same member for its second subscript and add, there results = 3 le dA, dA, Aig A Re ns A > Ais Ae ( ee ic (52) k=1 j=1 dex, dx; An interchange of 7 with # in this should not alter the value of the right-hand member of the equation, but it obviously does alter it to the extent of changing its sign, and the quantity is therefore equal zero, or Agr Ky -t A IKE + Bi oO BAge Ke => 0. For the determination of the functions ® we may proceed as follows. Denote the minors of A’ with respect to the element in the i + 1" row and &" column by Ai‘; then the quantity es th, ae uw dx; 1h —i represents the determinant found from A,, by changing the column of elements con- taining differential coefficients with respect to 2, into a column containing differential coefficients with respect to z;. In general then this determinant must vanish, as there will exist in it two columns containing the derivatives of the functions @ with respect to a. Ifj—=k the determinant becomes simply A,,. In case 7 =h the determinant contains no derivatives with respect to a; and for that case i=n—1 dé, aes > Fit Sh =e Ai, D = dx. a ct since . adA,; dA,,. 6; a | dé; aie d dz; SIMILAR TO THOSE OF HYDRODYNAMICS. 375 In all cases, then, when the above deter ant does not vanish, it is equal to either A,, or — A,, Multiplying it then by = oe * and summing for h and /, from h = 1 to h=vu and from * = 1 to k = w we have Th Ss os dA, , dO, fit a Sy a, An -> v Pa i ee EY fin dary st ae Now the function A; may be written in the form k=n d Ay; h=n dA, XK; — 22, mARr =2 Ae Sonee (a) = dx, Ly da; This differs from the second member of the last equation merely in sign. This equa- tion may be written in the form i=n—1 db, k=n h=n dA,, e A da; = At, = — K; . (B) Now since . d Aik dA adAy, [Ge is ona ar gee day, the quantity in brackets can be written k=n qd =n ’ | Set Anat (”) Now as we have for the determination of the functions ® a set of equations of the form z do, dd, al dA, dAy; Di oe, 1 24 de, +: pia = 2 Aa, ae) Now observing the equations (a) and (8) we have at once by comparing the coef- ficients of a k=n h=n ad. fi. a=—-> > 4 ay, (53) =e sl or, on taking (y) into account k=n iS » 7a A), Asst (54) Now since it is obvious that the quantity in brackets is the sum of the differential coefficients of d6; 2 q with respect to 7, and therefore finally 376 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS dda ,d a Gs — = + tee. dx, 74% dit, 7 40; da, 7 18; Thee dz, ore dry @ dz, (55) If we multiply equations (50) by A;_1,1, Ai—1,2,--- +» Ai_i,n respectively and add, we shall obviously have il @,= 7 (Aisa Ai ia a To Ai Mg) (56) a form of ©; from which some interesting results may be obtained. Substituting ®, for its value in (28) gives =n—1 d(U—q)= SS rept = ©,db, (57) == and from this we obtain at once d(U—q) _ dA 11 d6, do, dx, meh a 5 a si ®, dx, saith a4 daz. d(U— q) __ = i dO, dO, -4 dz, i Dy oe + db, dz, Bone ah, Dyes dz, (58) d(U—q) _ dA,, dé, d6,_ 4 qe $0, +0, G+... FO re For the case of steady motion the first terms on the right side of (58) drop out and the equations take the form d ( 0 — 7) d9,,_ On 1 dx; = = &, 5 Z tg &, 5 7 oar Ae ees ar ae dx; (59) Multiplying by dz,, dz,....dz, respectively and adding, we see that for steady motion the functions ® are ihe differential coefficients with respect to 0, O2,..++, A.—1 of a function. W= U—q= W (0,6, . 5 s =JOe=ay 1, €. dw dw dw Cane ®, = GH, -°+° Pn-1 = Ba (60) The operator d An J + pF +...+t Ais ae is well known to be equivalent to d J aH SIMILAR TO THOSE OF HYDRODYNAMICS. See If we multiply now equations (58) by Ay, Ap,...., Ain respectively we have by virtue of this relation between the two operators d(U—q) _ aw 1 dy i 3 GA ae (61) and consequently 1d W=U—q= [57 d0+V (OO... O11) (62) W being a perfectly arbitrary functional symbol. This might be expressed differently ; since @ is the only variable function we must have db, do do de, Mt gy Ua +. . : -+ g &, = 40 dé dé dé de, 1 = es data + ....-+ oes dx, = 0 from which follows A,,d6 dx, = ee A,,d6 a He) os si Substituting the value of dé thus obtained in the above equation we are enabled to express the integral in terms of 2, %,...., 2, In order however to obtain the value of the integral in (62) it will be necessary to express aa... .. 2, in terms of 0, 0,, 02, . +++, 6,1. To this end consider the Jacobian = 4 A UN COn Bn aot Vn) (63) : : dw dw - The minors of A corresponding to 7 , 7 ....are the same as the minors of J corre- t,? dx, dj dé c = - dd; 2 sponding to 7,» g,-+-+ The minor corresponding to 7, is CW i ae dW. é Bay Une cea ST amo Oe mage = Th (64) which is again a Jacobian. Denote the principal minors of A corresponding to ele- ments in the first row by An, Aw,...., Ay, and by Aji, Ajo, .. +, Aim Corresponding to elements in the ** row. Now as we know : dA, dA;5 fe + dx, d +....4 G7 =0; (65) 378 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS the quantity (64) is = A”, therefore (65) becomes Lh je d dW Danes = bas fa | = 0. (66) Lai a J From equations (58) we have, however, dw dA; dd, dO, ‘dz, dt + diz, + ®, 2 da; d0, 5 + jo a) ow fe a rap) —— SE lees Substitution of this in (66) gives a series of terms of which the first is h=n d a, =: aes > dx, |e EB ai}, eee? ,, Ath oe = Cy Ah This is = 0 for all values of i other thani=1. Similarly for all the terms until the *: the coefficient of ©, is then = A,,. Now this substitution gives before reduction h=n j=n = =< d6,,_, tis 0= pie: ae 5 [4b Ce dx; + rae a a D, 1 dx; dt ie ft Ne Pos | on performing the above described reduction this becomes h=n = = Ey A; 2a is (Ar, ® i) ces 2a dx, iG dt At) = (68) Since the first and second minors of J, i.e. A,, and Aji, all satisfy identically the equation of continuity, (68) may be written in the form 1D. d® d®. lee l Ais Ze, qi 9 ate Aiea + ©, = 0 dP. d®, d®, An ae, 7 As ae sgt Age sa (69) d®, 1 d®,_, d®,,_ Ay dx, t Aj dit pea Tae dik, et in which h=n j=n ra. 1A, ; 2S eS ae (70) =ee dt dx, Again, by aid of (53) we can replace (69) by d® d® d®, = Aj, ae + Ai ie ode ahi dz, Sioa =X d®, d®, d®, d®, Anas | te Aggie de, sty ae Xp (71) d®,, _ d®,, _ dd, d®,, _ Ay Te + Aj ea a ca ea a be dz, =e di = eas SIMILAR TO THOSE OF HYDRODYNAMICS. 379 in which nr t=n : 2 dA” dA*, A: {= = = dx, dt (72) The modifications undergone by (69) and (71) in the case of steady motion are obvious and need no remark. The equations Tey dary Ge dG = Ua, ete. have been replaced by dat, dx, S G = An HE = An, ete. (75) If we have dO, Grae then @,, = const. is an integral of these equations, and similarly for any other of the functions #. If then d®,, d®,, d®, d® d®,, a : diy + Ay a, sae Sarre ie pit eS and in this case ®, = const. is also an integral of (75). If all of the functions 6; are independent of ¢, we shall have 0, = const., 0, =const..... 6,, 1 = const. as integrals of (73). Suppose in equations (10) that the functions w were Up Uy Ug. ++ Ulan then it is known (see article of Professor Tanner’s above referred to) that Ug Oy AU Gay a = 2 Ug, All can always be reduced to the form aM, a a, indi, =< 7 and dM, dM, dM, Uk = Gees + Ly dx, ae “+L, dat, (74) In this case we should also have k=2n jH2n k=2n In, Any. In; El {U—q)= & ie det 4 > Si ae é di) (thd, — weil) (75) 380 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS Now clearly oer yw a r r=2n || da; day, dite =o dx; di, = || dM, dM, dx, The double sum in (75) thus becomes p=2n dL, p=2n dL, ao a p dx, = ax d. p p=2n 7 p=2n 77 aS So p=0 p=0 and since dx; Ries ie this is r=2n { | D d | z | = dM, || dt dt Pe oe ] La =0 [Nota ee | uw, H, |l Substituting this in (75) we have, after some ee tt = dM, d ae L,. dt The equations > (& A = | (76) dU duty duty duy duy Ue ye tue te Lae = diy diy dit ea tha, thm to tte de, (77) dU a Abs» duty y dyn, dis, = Sse Up di 25 Uy dx, =F ee AY == U2 n Axon and duy diy duty Alyn __ Parr rs ieee oe (78) are thus replaced by a set of the form dL, dL, dL, di aa ae + Uo Gy, 1 ge, +E tae ae, — ae, (79) dM, dM, dM, dM, dQ Ge 8 ae, Ok a ee (78) remaining unchanged. In (79) 7 has, of course, all values from 0 to 27, and 0 is an arbitrary function of the L’s, Ws, and ¢. For U we have now SIMILAR TO THOSE OF HYDRODYNAMICS. Sac al aa aMy pete SARI +3 1,941 (M+ Sr Bl+o (6) Equations (59), which correspond to the case of steady motion, give us, on multiplica- tion by A;_11, A:_i,2,--- + Aj_1,, and addition of the results, 1 dw dw dw eile, Sera ee — (81) expressions similar to (56) for the determination of the functions ®,. We have seen that if we have ie ae (82) then @, is an integral of equations (73) or of da, dt, dee, 7 UND Ge OS ae (83) In order now to obtain an idea of the nature of the functions 0,0,....6,_1, consider a function of the x + 1 variables a, 7... . %,,,, which denote by f, i.e. efi (Ca ate nes This function f which satisfies say JS = const. sustains the same relation to the space of n dimensions as a function of the three variables x, y, z, and also of ¢ sustains to ordimary space, so for want of a better term I shall speak of it as a hypersurface. Now suppose the hypersurface f to be composed always of the same particles, it must obviously satisfy the differential equation ¢, ¢, a df de) ht de, be gy tT On oe Kp =i) (84) (84) has as we know n independent integrals which we may denote by @ yOpo Og v2 04S The equations ?=const., 6, = const., ete. are, therefore, the equations of moving hypersurfaces which contain at all times the same fluid particles. The particles which are at any time on the intersection of any n — | of these hypersurfaces will remain on that intersection. As before we denote the Jacobian of the functions 0, 6, 0,....0,-, by J. So far as it has been con- VOL. X. 49 ’ 382 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS venient from considerations of symmetry to write 0, 6,, 0... ..6,—1 as our functions, for the same reason it will now be more convenient to write 0,, , 0;....0,. In all that precedes, then, the function @ is identical with the new @,, and in general 6;_, (old notation) = 6; (new notation), The minors of J corresponding to do, d0, db, dx, dit, dy are Ay, Ay... A,, respectively; and similarly for the other rows. If we solve the equations dé, dé. Ly i” oF tle gaat set ee dé, dé. Bu tw Gt. eee z= (85) dé, do, do, dé, ce di tty ge + Ua gy He 1 Un ag = 0 we find dé, dé, dé, Es Fee |e Au ge Se ate : dé, Jin =—\"7 Aes Ais 22 sis a ee (86) (db, dO, db, Fig = — $F Asa + GE Aan to + FG Aaah Substituting these values of w in du, = 4. ~ == ietge caer =0 ma and we find by the rule for differentiating a determinant dJ dt dt dJ tht ph a page els he eee aE (87) or J satisfies the equation DI 7 = 0 (88) D It would be interesting to determine the effect of the operator 7 upon the various minors of J, but it is sufficient for the present purpose to find Fhe effect produced upon the first minors by this operator. The method of doing this is, in the case of SIMILAR TO THOSE OF HYDRODYNAMICS. 383 Aj, to erase the first of equations (85) and solve the remaining n — 1 equations for Un, Ug,» -++, Un. We have after doing this dé dO, dO, dd, Auta =—}[ ae Cay ae ola sete [rahe oy ae ee raf ag x [le 1M de a = *[ets a] at au [es Tt ae wn] An | - . Differentiate these with respect to x, 73, ...., and add and we readily find DA, du, du, du SS, aut pas ney cee t dt An da, =- leg dx, St = 6 se + A dz, and in like manner DA,, du, du, dit @ —4ng + Ang, +--+. + Ain ae a ; dus dt Sen pet ee te cat A ae (90) DA, __ du, du, Ay, dt a Aang te Ata gee ats sna At es If in these equations we substitute for A,; the other principal minors A,;, A3;,.... An; (i having all values from i = 1 to i = w in all of these) the equations will still hold. I do not write the proof of this out in full, as it is extremely simple and yet rather tedious. If we combine the equations 0 = const. in groups of n — 1 each, we shall of course obtain the z lines representing the intersections of n hypersurfaces represented by the equations = const. Call these lines s,, %,....8,; and denote by ds,, ds.,....ds, the n sides of an element of fluid occupying the space between the hypersurfaces 0, =a, 6, = on.-.-0,= 4, and 0, = a, + da, G. = ae day 2 Op — ay 1 Oa.,. We must have now i = 6, (a; , 2s spade i@eg sb) (91) ay + da, = A; (x + Ands, + Xo -{- hye sy eon te Ly + hy nS, 9 t) the quantities 4, A2,--- - 41, denoting the ‘direction cosines’ of ds,. Similar equa- tions of course hold for a, a3,....a,- By Taylor's theorem we now obtain 384 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS dO ’ da, = Voge fg a ee d6, do. dog = | ax get Dan aot + + Faw a aa ds, (92) do, do, da, = Vitae Gt hatte A an Se | ds, The values of the )\’s are known to be A, A n= Ze? a = Fe, ete... (93) where 2qg= A+ A,t+....+ A},. (94) Similar expressions hold for \, (j =2,3....nandi=1,2....m). The quantity 2q can be expressed by a determinant viz. | Coe Cog O” | || Cx Cg ee ss C3n | | Cr Cn ae eet | in which : dO, d0,\2 Co = 2 & ; C33 = > aC Jétont oe dO, dO, db, a6, (96) Oa dx, dx; Ca = dx, dex; ete. j taking all values from j7=1 to 7=7; oa Cx. = ¢4. Substitutmg the values of An» As +++ +> Arn from equations (93) in the first of equations (92) and we find at once 2q,d ds, — oS a — 2¢ 3 (97) similar expressions are to be found for ds,, ds;,....ds,. Denote the projections of ds, on the axis by dxP, dx), .... da; then from what precedes ote, VEY SAB Ars | dé, dé, d6, db | da,? daz? *' °°? dit, ade? + agd2® +o... + uydx® = a ites (98) ii, db, a de,? de) °° °°? de, SIMILAR TO THOSE OF HYDRODYNAMICS. with similar expressions resulting from the projection of ds,, ds3,.... axes. Comparing these equations with (39) and writing 385 ds, on the U+q=W (99) gives D do, a (mAy + Ay +.... + trAin) 7 = AW (100) and by (88) D LW 5 (An + tA +... . + uA) = JG, (101) and in like manner D dw dt (2,Aoy + Up Aog a eeee a Un An) — J i, D dw dt (%4A,1 =e UrAns + QO oD =e UnAnn) = J do, Assume a function P such that DP | a a (102) then since d d d d Au Ge, + Aw a, +++ + An Ge =I & ete (103) we have dP WA - tAp ins. UA, — oe a it dP sicher an Aleta ta ag, + vet (104) dP UWAny =r UA» oe Bias, = UnAnn = J } do. oF nt The functions y contain 6,, #,....6, but not 4 Solution of (104) gives dé, (dP dd, (dP do, (dP w= NGG th + Se ae tt ae ae a, + nh ete. bearing in mind that 4a [=> (105) These equations for %, Ug.... U, may be written in the form 386 GENERAL PROPERTIES OF CERTAIN PARTIAL dy ia ie + YA ia ce We de dP dO, dy = aa ae ee a Uz dO, 0, at th Ge, th and from these follows ux, + ugdt, +. . - - UnAX, = M2 + dO, + Wl, aR DIFFERENTIAL EQUATIONS db, ty the (106) do, ye eat Wr Ey +48, (107) This result may be obtained in another manner which will bring into evidence some interesting properties of the functions with which we are dealing. The method to be employed I shall merely indicate, as it is similar to that employed in obtaining equations (61) and (62). The original equations of motion are Du dU Du, __ dU ae nae di = Gr, ete.---- (108) now d _d0, d | dh a do, d Tay des da, ag a Se a (109) and consequently Duy = dU , dU dé, dU dt , dA, +5 a dO, aes dx, dé Du, _ d6, dU , dU do, dU aie = Ge aac Ee ea a (110) Du, d, aU a dU oe it dU dt ~— di, dd, r, Ws , 1, Multiply these by Ay, Ay, - . , A, respectively; then by Ay, Ag, . «ei a9, Ang ere= spectively, etc.; add in each case and we shall obtain | Du, Du, Du, | Wa eae eek ar | dé, dé, dO. dix, ? datz? ~""~? dit, d6,, dd, dé, dx, ? da,?****? dz, age ete. eit (111) SIMILAR TO THOSE OF HYDRODYNAMICS. 387 Now we have found that DA, du, dx, du, du, = Ay + Ap z+. + + Ain a Using this equation, and also equation (103) and we are enabled to write at once A ain Ce J &, DAT de, dt ~~ do, (112) DA,, + Wy, dt J d0, Multiplying these by %, %,....%, respectively and adding the sum to (111) we obtain Qi wras Up sreeean UR, dé, dé, dO, ee 6) Pa) Oe) ee D i dx, dz, Pel dt ee aes do, do, dé, dx,? dx,?'***? dit, there are of course n — 1 other equations of this form which can be immediately written down. Since DJ fia) : : D we have, if we wnte P=—, Uy, Uz, +++. U, the same expressions as those marked (106). integrate and solve the resulting equations for Norr.— I desire here to call attention to the paper published by Professor Rowland in the American Journal of Mathematics, Vol. III. No. 3, in which & full account of the so-called higher orders of motion is contained. (I may also mention that I am informed by Professor Rowland that he gave a brief account of these motions at the meeting of the Scientific Association of the Johns Hopkins University on October 6th). The existence of these motions was discovered at about the same time independently by Professor Rowland and myself. He was led to consider them while treating of the equations of electromagnetism, and their connection with fluid motion. I was led to similar results by the study of certain possible cases of steady motion in viscous fluids, an account of which will be found in the Journal of the Ftanklin Institute for October, 1880, and also in the Philosophical Magazine for November, 1880. 388 GENERAL PROPERTIES OF CERTAIN PARTIAL DIFFERENTIAL EQUATIONS, ETC. I had devised no simple means of determining the lower orders of motion in terms of the higher orders, but had merely derived the higher orders from the lower by obvious processes of differentiation. In Professor Rowland’s paper an elegant solution of the much more difficult problem is given. I may further say that up to the time of my becoming acquainted with Professor Rowland’s research I had found no physical interpretation of these quantities so that the entire credit for the development of the theory of these motions is due solely to Professor Rowland. In the present paper the quantities corre- sponding to the higher orders of motion are denoted by the letter 7 with different accents and subscripts. My work on the subject of the higher orders of motion is to be found in the paper quoted at the beginning of this article, “General Properties of the Equations of Steady Motion.” I believe that Professor Rowland has made no use of the integrating factors which I have there introduced. This part of the subject I hope to go into quite fully in Part IJ. of the present paper. Wasutveton, D. C. January 2, 1881. = Ve. A Comparison of the Harvard College Observatory Catalogue of Stars for 1875.0 with the Fundamental Systems of Auwers, Safford, Boss, and Newcomb. BY WILLIAM A. ROGERS. Presented December 14, 1881. Sryce the actual construction of the catalogue of stars found in Volume XII. of the “ Annals of Harvard College Observatory,” five catalogues of the principal stars of the heavens have been independently formed; for the most part from complete discussions of all the data available previous to the year 1872. I name them in the order of their publication. (a) Fundamental-Catalog fiir die Zonen-Beobachtungen am nérdlichen Himmel; herausgegeben im Auftrage der Zonen-Commission der astronomischen Gesellschaft. Von A. Auwers. (6) U.S. Geographical Surveys. Lieut. Geo. M. Wheeler, Corps of Engineers, in charge. Catalogue of 2018 Stars for Jan. 1, 1875. By T. H. Sarrorp, Pu.D. (ec) U. 8S. Northern Boundary Commission. Declinations of Fixed Stars. By Lewis Boss, Director, Dudley Observatory. (d) Catalogue of 1098 Standard Clock and Zodiacal Stars, prepared under the direction of Smion Newcoms, Professor U. S. N., Superintendent American Ephemeris. (€) Verzeichniss von 83 siidlichen Sternen zur Fortsetzung des Fundamental-Catalogs fiir die Zonen-beobachtungen am Nordhimmel bis zum 31. Grade siidlicher Declination. Von A. AuwEnrs. VOL. X. 50 390 COMPARISON OF CATALOGUES OF STARS. The first of these catalogues contains the positions of 539 stars, symmetrically distributed over the entire heavens as far as 10° south declination. The authorities upon which the codrdinates of these stars depend are as follows : — Pulkowa sb. << t eo le aren aoe | se BES Bulkowaew ty eco bien cate Seis ots te Prem S6D 5 PulkOwas: ie 4) Nes ee ee ee eect A) oe el oyyil Greenwich) 522 scene) sinters LS BO SLOG Ee CONEEE Fn oe 5 oo oo G oo oe og 6 IS 2 bo on 4G ots 6 A oo Bea Oo 6 Go oo URGES Teen =o Ss | S bo wo VoD ie lor or) Bane he.) M) +++ +++ +++ +++ He b+ ++ ou on =) oO The corrections given above may be assumed to be true for the mean declination of the group to which they belong, and for twelve hours of right ascension. It is COMPARISON OF CATALOGUES OF STARS. 393 apparent, however, from the following comparison of Auwers with P’ that the correc- tion belonging to any group cannot be regarded as constant for every right ascension of that group. AUWERS minus P. Aa —10°. ..+0° | +0°...410° |+10°. .. +-20° 420°. ..-+30°|+30°... +40°]+-40°. .. +50°|-+50°. ..+60°|-160°. . .-1-70°|-4-70°. . . +859 _ot1 | +.014 | +010 | 4.011 | +.089 | 4.046 | 4.087 | 4.17 | +.162 +.011 01 +.010 +.014 +.061 +.062 —.008 +.096 +.052 +.003 A +.031 | +.000 —.009 +.081 +.069 —.016 +.036 2 ieee On +.069 +.043 | +.097 | +.044 | +4.027 AS 40.25 | —0.11 | +0.31 = 29.6) |e ela > ere = 10) | S12 + .06 Se ie || es atl 25 Bb +0.40 + .65 + .43 - Al i—) hom ton ++4++4 Org OO Auwers minus Safford. Aé ” "+ +4441 [++ ++t+t++ +¢4+4+44+ ++ 144+ +4 +++ +4++4++ +41 394 COMPARISON OF CATALOGUES OF STARS. The corrected residuals, in the case of Safford, in declination, of Boss and of New- comb, are so nearly constant, for each group, when arranged in the order of declina- tion, that it may be safely assumed that they are not a function of the right ascension. In the case of Harvard College and of Safford, in right ascension, the evidence is decisive that the residuals in certain groups vary with the right ascension. This is to be expected in the case of the Harvard College observations, since the deviations of the fundamental system upon which they depend, from the system of publication XIX. are functions both of the declination and of the right ascension. The provisional catalogue designated P is based upon Bessel’s constants of precession. The same remark applies to Safford’s catalogue. For the conversion from the constants of Bessel to those of Struve, we have the following relations between the annual varia- tions in a and 6 for 1875.0 : — 8 8. Struve = Bessel +.001123 +.000129 tané sina. Struve = Bessel +.00194 cosa. It will be seen from these relations that the change in the right ascension in a century may be as great as 0°.11 for a star on the equator, while the change in decli- nation will be insignificant, the maximum value being only 0°.19. It is also apparent that the residuals, especially in right ascension in the column Auwers minus P, are for the most part due to the change from the constants of Bessel to those of Struve. For the more complete reduction to the system of Auwers, we have the following additional data. Auwenrs nunus HAarvarD COLLEGE. 120... Aa s ~ Ud s 8 Ey! | a0 A —.037 i — 037 058 3 5 —.010 : —.021 —.045 63 08 +.005 6 —.018 —.046 08 +3 +.002 —.014 015 —.005 +.005 —.007 —.002 —.006 —.017 —.015 NT +.007 —.003 —.007 —.010 +.018 +.000 +.020 +.008 +.043 +.041 +.052 +.017 +.009 +.009 +024 +++4+ 4444 ++++ +444 COMPARISON OF CATALOGUES OF STARS. 395 AuWERS minus Haryarp CoLLEGE. — Continued. jt by Le! Aa b o 8. +.038 +.061 +.055 +.057 || Sr HS So re ie +++ | +.065 +.058 +.060 +.045 +.059 +.061 +.047 ase Sie: PO aie J eee +++ 444+ 41 Wee ee AUWERS minus SAFFORD. +.058 +.045 +.048 +.053 +.042 +.037 +.050 | : +.029 +.026 j +.045 +.012 +.060 +.014 +.055 +.022 +.068 +.072 +.088 +.100 +.042 +.040 +.026 +.013 +.052 +.010 +.090 In the reduction of a given series of observations from the system of one funda- mental catalogue to that of another system, it is obvious that the most independent method of procedure would be to apply to the given series the systematic corrections derived from comparing the system upon which it is based with that to which it is to be reduced. The fact already stated that the Harvard College Catalogue for 1875 depends upon two systems which differ systematically, makes it imperative that the comparison shall be made directly with the system of Auwers. There is also an addi- tional consideration which makes it necessary that this course should be pursued. It 396 COMPARISON OF CATALOGUES OF STARS. will be seen from the values of Aa under Auwers minus P’ from +70° to +85° that the right ascensions of the Polar stars between 0" and 6" are about .10° too small, while those from 6" to 18" are nearly .10° too great. Hence, in the determination of the instrumental constant 2, the values derived from observations made between January and April will be too large, while the values derived from observations made between April and September will be too small. For stars beyond 10° south declination there- fore, systematic errors in right ascension will be introduced through x, which will not be corrected by a close adherence to the fundamental system. In the conversion from one fundamental system to another, two methods have been employed : — (a) The Analytical Method. If we have a series of residuals Aa, arranged in the order of right ascension, which are strictly circular functions we may always have : — Aa =a constant + m sine + n cose + m' sin2«e+ mn! cos2«, ete. aL ? If Aa is a function of the declination we may have approximately the additional equation : — Aw =a constant + @ sind + b coséd. (2) In practice it will ordinarily be sufficient to assume : — Aw =a constant + m sine + n cose + asinéd + 6 coséd. (8) In Volume X. of the Annals of the Observatory the values of Aa were first com- puted from equation (1). The computed values having been subtracted from the observed values, a new series of residuals was obtained which were assumed to be functions of the declination. New values of Aa were then computed from equations of the form (2). The total correction was then assumed to be the sum of these two computed partial residuals. For the residuals in declination we may with less exactness assume : — As = a constant + ¢ sind + d cosé. (6) The Graphical Method. If we assume any given unit in right ascension as a horizontal argument, and an aliquot part of Aa as a vertical argument, it is obvious that points representing Aa may be laid off which will bear a definite relation to a fixed horizontal line. If a smooth curve is drawn through these points, values of Aa nearly representing obser- vation may be derived for any right ascension by reading off the vertical co-ordinate passing through the curve at this point. By a similar method of procedure we may obtain the values of AS which represent the observations. COMPARISON OF CATALOGUES OF STARS. 397 Each of these methods has its strenuous advocates. The objection most frequently urged against the first method is that in an analytical solution, extended to terms of the second order only, there can be only two points of inflexion in a curve represent- ing the computed residuals. If therefore the residuals between two systems are really represented by a curve which has several points of inflexion, the analytical method must be less exact than the method of graphic curves. Again, it often happens that residuals having the same sign and nearly the same magnitude are concentrated at one point. The effect of the analytical solution is to distribute the assumed errors at this point over the whole system in such a way that the sum of the squares of the residuals shall be as small as possible. But if these errors are real, they belong to this point only, and they should xof be distributed over the whole system. The objection to the second method is that for a given series of points representing Aa or Ad, no two persons would describe exactly the same curve. This objection is to a certain extent obviated by the plan of successive bisections of the lines joining the points, described by Professor Pickering in Vol. X. of the Annals of the Observatory. In drawing a curve by this method, two points require attention. First, that the uncertainty with regard to the ends of the curve will be increased in proportion to the number of bisections, and second, that each successive bisection causes the curve to approach a straight line. In order to draw a regular curve, it will rarely be neces- sary to make more than three bisections. It is my custom to use the curve drawn through the final bisecting points as a guide in drawing the curve most nearly repre- senting the observations. To this extent, therefore, the final curve is dependent upon the judgment of the computer. The uncertainty thus introduced will rarely exceed .0058 for any residual in a, and will, I think, never exceed .01°. It is obvious that the case in which this uncertainty is the greatest is that in which there is a sudden change in the direction of the curve, followed by a nearly flat curve for three or four points of the horizontal argument, and this in turn followed by a sharp return to the original direction. As illustrations of the degree of conformity which may be expected from the two methods, I give below in parallel columns the observed residuals, the residuals derived from the equations, and those derived from the graphic curves, for the following authorities : — Catalogues compared. Equations. 8. 8. 8. 8. 8. I. Auwers minus P'; Aa from +70° to +85° A@=+.069 +.065m +.0412 +.029m! +.011 7! II. Auwers minus H.C. 0.; Aa from +70° to +85° Aa =+4+.033 +.007m +.029n —.009m! —.001 2! ” ” ’ ” TII. Auwers minus Struve; Ad from +70° to +85° Ad =+.03 —.08m —20n +.03im! +.09n! IV. Auwers minus Safford; As from +10° to+70° Ad=—09 +4.57¢ —A8d WOlbs 5 51 398 COMPARISON OF CATALOGUES OF STARS. Aa Observation. | Equation. i O—E O—C {§ Observation. | Equation. s. 8s. | 8. s. s. 8. +.149 135 | +.005 | +.019 | —.008 | +.058 | +.173 ie +.014 | +.014 f +.121 +.050 | +.149 alas | —O020)) — 010) 322050) |) --043 +.097 P —.011 | —.031 | +.019 | +.039 +.057 : +.062 | +.042 | —.013 | +.026 | +.041 015 —.082 —.056 j +.051 | +.010 +.036 OU +.060 | +.095 | +.001 —.002 +.023 00 —.030 | —008 7 —.009 | —.002 OO x= toe +.023 | +.012 | +.009 —.016 | —.050 # +.035 +.012 | —.008 +.078 5 | —.908 | +.003 +.063 Curve. , Observation. Equation. ” ” ” = 08 07 2 ELS | ==39) 460) | | 5 09 Pe 20a Bin lee al SS5G 0 (an eS Ten eaten Sek pes | 109) ) aru ees —.25 | —29 | — | +.08 | 4.45 25...485 28 | —.28 SESS |) S22) |) Sell Se eA —.16 S299) 4[aaOd. | eee 35...+45 Sin =20 +.26 | +.24 Yeeee5e : == 115} || +.10 | +.18 | ==03"| 01 — 08 | —13 Alls} |) a The residuals under Auwers minus P’ and Auwers minus H. C. O. involve compar- atively large accidental errors. Those under Auwers minus Struve, and especially those under Auwers minus Safford, are nearly free from accidental errors. While there is a close agreement between the values, 0— # and O—C, in every case, it is obvious that in the first two cases there is little to choose between the two methods, but that in the last two cases, the graphic method yields the best results. The choice of the method to be used depends, for the most part, upon the magni- tude of the accidental errors, but unfortunately it is often impossible to decide whether the errors are real or accidental. The graphic method is by far the most expeditious, and with hardly an exception it may be safely followed. COMPARISON OF CATALOGUES OF STARS. 399 Both of these methods of comparing different catalogues, are open to the objection that the codrdinates of any given star, when referred in this way to a normal system, may differ by a small amount from the values of the codrdinates derived by a direct reduction of the instrumental constants from the fundamental stars of the system. I estimate the uncertainty arising in this way to be .015° in Aa and 0.20" in Ad. In the reduction of the zone stars observed at the Harvard College Observatory, the instru- mental constants from 1871 to 1876 have been recomputed from the positions given in Publication XIV. When, therefore, the final catalogue is completed, the data will be at hand for a definite determination of the amount of this uncertainty. But since this reduction is wholly impracticable in the case of catalogues already published finally, some method of reducing different catalogues to a homogeneous system is a necessity in the determination of proper motions. Admitting this necessity, that method is to be preferred which will reduce the residuals in Aa and Ad to a minimum, whatever the order or the limits of the groups into which they may be divided. The method pursued in this investigation is the following : — (a) The residuals are first arranged in the order of declination. The mean values for any group represent nearly the corrections for the mean declination of that group and for twelve hours of right ascension. (2) The residuals for each group minus the mean value for that group, are then arranged in the order of right ascension, and a graphic curve is drawn through the points representing these values. ach curve will give a series of values for the even hours of right ascension, which are arranged in vertical columns, the horizontal argu- ment being the mean declination. It will be seen that the values in the vertical columns are derived from the same curye, while those in the horizontal columns are derived from different curves. In order to connect the different groups in declination, a curve is drawn through the points represented by the residuals in the horizontal columns. This will, of course, disturb to a slight extent the values already found in the vertical columns, but they can be rectified in the way already described. A second approximation will ordinarily give smooth curves for both the vertical and the horizontal arguments. In this investigation, however, I have preferred to retain the values derived directly from the original curves without any attempt to smooth them. (c) On account of the limited number of the residuals which usually compose the groups arranged in the order of declination, there is danger of introducing systematic errors in drawing the graphic curves. Hence after the sum of the two residuals already found has been subtracted from the original residuals, the new values are 400 COMPARISON OF CATALOGUES OF STARS. arranged in the order of right ascension and a curve is drawn through the points thus found. REDUCTION OF THE HARVARD COLLEGE OBSERVATIONS TO THE SYSTEM OF AUWERS. It is not considered necessary to give the details of the reductions which form the basis of the tables given below. After the sum of the corrections determined by the method described above from groups between the limits 6 = —10° and 6 = +80° had been applied, it was found that the deviations from the normal system were as follows : — AUWERS minus HARVARD COLLEGE. Residuals in a. Limits Limits in Limits in é 6 Limits in Eolas 295 |. og 22% Fine —.010 30s 2 | 004 Bee 4.003 —.004 DASH Bagi d | +.000 Dis caete +.000 +.005 es 5 | +.004 ster +.000 —.001 | —.009 aaa —.001 or tro Sr —10... 2D 6 OG . | +.009 — 5... eDhiskests 2. +.0038 JE ag 2S 6 y y —.006 +5... —,011 | —.008 joe —.005 —.002 30% +.004 +.004 Pro. +.001 | +.002 309 +.008 ++++ 4] +.002 —.006 =. Oi! +.000 +.003 40 —.003 | +.004 +.002 | —— 0055] ee Ohne +.002 —.014 y +.003 ne a a + + “p + hoe paps ror or or PARSE DIN oven O1 or +.003 +.005 +.003 +.005 or ror en +.002 +.001 == 00 —002 —.006 —.002 —.025 COMPARISON OF CATALOGUES OF STARS. 401 Residuals in 6. Limits in J r a a i et Limits in a ” ” " " +.00| +.14] —. .2. 4] 4.11) +.07 —.06, —.06 ; +.03, +.00 +.21) +.36 05.09) 14 <8. 5. +.24] +..16 —.19 +.00 ! suche +.05) +.22 03 —.08] 4.15 = ' 196 —03 +17) —18 +.16] —.06| +.09 | 20... 24 | 4.05) —17 Means by 3 aYD) p n Means by ) Weights. § “"""| — : spell) S(t) Weights} o--- It did not seem necessary to recompute the double argument corrections in a, but for the terms depending on a and 6 new curves were drawn from the values of Aa given above, and the secondary corrections obtained were applied to the corre- sponding values given by the first set of curves. The residuals in declination, however, appeared to require a complete second approximation. Accordingly, new curves were drawn from the residuals in 6, in the manner described above. The results from the two approximations are combined in the following tables. Aa. AUWERS minus HARVARD COLLEGE. Corrections depending on Q@ Aa 6 4 Aa Aa Aa 3. j 5 i 8 Be h. 8. —,048 : : 0). —.014 +.006 ; +.004 —.041 : 50 | +.0504 0. ; 55) || XP) +.002 0 | +.007 —.033 003 | +52] +.0479 0. 010 OM 2026 —.001 +.009 =I P7/ : +.0429 0. 4 —,.025 —.005 +.014 = (0Pil ) | +.00 56|+.0381 0.! : vl || opal || ate! —,.008 +.017 = O07 OC SL 337(|,) ie{0 OL: 4a) |) Aol —.010 +.019 —.015 . 10 | +.086% 1. ; —.014 —.011 +.019 il) 0 1 +0388 1. OLS : — oii! —.014 9. +.007 —.007 5 +.043 9 2. O15 8 | —.007 —.019 +.014 —.006 | - O18 56 | +.047§ 2. OLE —.006 20) +.010 —.005 | +22 02 38} +.0489 2.8 : e002 —.017 +.005 —.005 | + .028 ) | +0484 3. 008 +.003 —.008 : +.007 § —.007 .035 +.045] 3.2 | +.002 +.010] 15.4 | —.004 +.007 —.010 : 035 +042) 3.4 | —.001 +.018 —.002 +.005 —,.012 | +30 | +.038 +.036) 3.6 | —.003 +.021 +.000 +.003 | —.014 | +: : 78|+.025] 3.8 | —.007 5 | +.016 —.001 —.005 —.015 4 +.013 .0 | —.008 +.012 —.002'} 2 —.006 Shanis Ville ca ailltetettoutel [hevsuer|Peeoned Eee |P— O10 +.009 —.002 j —.004 402 COMPARISON OF CATALOGUES OF STARS. Aa. CoRRECTIONS DEPENDING ON BOTH a AND 6. [In units of the third decimal place. } °. = = 415° +-55° +-10° +20 TEEE FEEEH+ +4444 > Hs © bo 0 He bo H= Co bo © OIA D He bo Rte bo CO et et DS He AAAS Hop t= Se ee ee eer i yf sre , WN Oe Re wmwo WOO =-1N oo 09 bD bo 09 omo=10 Lil 2 09 ++ +++++ +4444 CO 02 et On 00 I Als Sg 1 ie ae ee eee 8!+4'+0)—7/—11|—7/+1/+ ¢ +11]+10|+6 —2\—8 —11/—7|+3/+ 6 is +12}+10)+-6\—4|—9]|—10|/—5|+-5/+ 6/+ 5/4 3/4 O|— 2|— 5/11/19} +12|+10454—9|— 8245+ 64 + 5i+ 3+ 1— 2 8) 9)|+11)+10|+-7,—3|—6|— 4/4 5+ 7+ 8i+ 8+ 8+ 9/4 84 84 3 | al Bi 4+-5i—3|—5|— 2)/4+-914-5 4+10)4+10/4-11/413) + 7 — 143474 9411411)4+11/411)413/418 414 = 9)4-11)-4+-13)2-19!4-14/415)415/413 041-23 — 1/+-5)+-6/+- 8i+ 8+ 914+ 84 84+ 9]4+13)/4-12 Om 09 O19 Ad. AUWERS minus HARVARD COLLEGE. Corrections depending on 6. cb oo p> | oo Oe He Oo ~ +++++ Go G9 09 09 OO . WIAD S| Ww WW bo bo to Pec areas He He Go tL ) Go GO GO b> on Or Or Or on Fee tear De a ee col el ell sell cl CON > © 09 Go Oo OO Orr Gh On bo mo ofan Hare res oer Paee eee Ran tars CO He ho Go Go tO CO SJOtrR wee 0o to WY WO bO 9| +4. 8] +. 7] +. || tee 5] +. 4] 4. 3] +. 2) +. il || sh bw eR tHt++ ++4+4+4 bS bo bo bo bo bob bo be COMPARISON OF CATALOGUES OF STARS. 403 Aé. Corrections depending on a. R SNSHDD FNWOMS wWORNWS: SIN oe DED S DARN OS MoOooL! o/s) 1 0. 0. 0. 0. 0. 1 1 2: 2. 2. [o co ello oo 2} © bo co 6 6 1 OS eel ad Beco coin Aé. CORRECTIONS DEPENDING ON BOTH a AND 6. [Lin units of the second decimal place. } ° S ao + 440° 445° | 4.552 pee yil— 4! 3|-99-39 +2)— 5|-13|-23)-32] +6|+ 0|— 9/—21|-39] paeaES -19) -29 36 =4\- ~11/-19|-27|-31 -6|-13 -20 _96|-28 -2 -10 -17| -22 -20 —18|—21|-17 Cr C9 He DD omgoann +++4+4+ tet tt oS OWONee 6 + 4} : uals16 17 : : 3) +20) +17] +16) +14) +12) 4 +36|+31 426 +20 +18} +19) +21) +26] +32) +33) +33] +30) +27 yaa +19 +16) +11 +54) +44) +34) +29) +15] +29) +31) +34) +35) +35 | +32 | +26) +23 +19) +15) 7-17 -10) ad + 56) | ze +16) +28 +35) 37| | +38] +87) +32! | +24) +21) +19) +16 ¢ W— 5+ 7 | | +50) 449) +42 +25 +18) +31) 434. 35 | 8) +23) +21) +19 +20) +18 | (410 422 +38] +29|+21/+10|+ 7 +23) +28 27| +23) 4 2)+ 7+ 6)+ 6+ 7+ 8)+ 9 = +11)+25 2-12 -17| -14|]-14| -11]+ 2/4 8+ 8 Hesay dens PM (eae esac aur 0414422] 3j-41 -42 -30 -23 -18)- 4/+ 6 | f —21) -20 -19 -15)-10, + 7 }+15 418) aa —44) -37| -30| ~21) -12)- 3)— 2/-12) -25| -28) 25-23 —24 -25/-21 -16 t 51 -48| -40 -31 -25 8| -15| -80| —30|-26 -2 “24 -97| —23 -15)- 9) 6|-56 48) -35 -19 -18)-14) 2| -17| -80| 81] -28] -25| -29| 19] -18] -14| -10 —56) -31) -22,-17 -14 5) -18) —23) -80| —29) -23 | —13] -13| -13| -14| -14 —37| —26| -18| -12) -11| | -22) 24) -21 3) — 2A 5)- 6/- =—23 19) SU "| 7| 18 -20 99|_04| -18 -12 }— 2) + 1+ 1— | | | 20 _19 ~16| -15|-11| -12| -15] -23| -25| -29| -19| -19 + + 3+ -35 -30 -26 -19 -17 -19 -29 -30) -25) -20 -15) 3)+ 4/4 22] 35] -36| -30| -22| -20| -21] -32) -31] -28) -22! -16|- 8] 2}+10|+ 7 24 =28 -26| -21| ~21 -26 -31) -29| -26 -21 -15)— 8 5] +14) + on Poo-p | +++ 1 DAMN PWNWRrOS ero ence oe ! « 404 COMPARISON OF CATALOGUES OF STARS. The following example will illustrate the use of the tables : — Reduction of the Coérdinates of v Orionis to the System of Auvers. a,=6 0 26127 §,=+14 46 52.05 \ 1 +.010 +.33 Corrections. < 2 —.026 —.11 (3 +.002 +.2 a=6 0 26.1138 6=414 46 52.51 In the formation of the catalogue which follows, the corrections were: for con- venience taken from the tables derived from the separate approximations. On account of the slight uncertainty in the interpolations from the double argument tables, an occasional deviation of four or five units from the results given by the final table of corrections given above may be found. AUWERS minus SAFFORD. Aa. Corrections depending on 6. |} +.038 +.041 +.043 +.045 +.039 + .034 +.035 +.042 oo © CO MAIS ore Go Yo +0.19 +0.21 +0.22 +0.24 = ta +0.25 —0.09 +0.26 —0.07 y +0.26 —0.05 : +0.26 —0.05 ; +0.26 —0.03 : +0.26 +0.00 +027 +0.03 +0.27 +0.05 +0.27 +0.09 a | OY | ° 1 —0.18 —0.18 —0.16 —0.15 —0.15 7 CF 1 T~1 OO Oo +++++ enone © COMPARISON OF CATALOGUES OF STARS. 405 AUWERS minus SAFFORD. AS. Corrections depending on both a and 6. [Un units of the third decimal place.] DOS ore _ + _ os + + + + = — 02 6 Ob bo Nore. — The residuals in a depending on a alone are so small that I have not considered it worth while to introduce them. AUWERS minus Boss. Ad Corrections depending on 6. ++tt+ +4+4+4+ +444 406 COMPARISON OF CATALOGUES OF STARS. AUWERS minus NEWcoMB. Aa Corrections depending on 6. AS Corrections depending on 8. non SHAW? 4+ a ao + bo oO +++H++ 4444 +++ +44] CATALOGUE OF 334 PRIMARY STARS OBSERVED DURING THE YEARS 1871, 1872, 1874, AND 1875, MERIDIAN CIRCLE OF HARVARD COLLEGE OBSERVATORY, AND REDUCED TO THE FUNDAMENTAL SYSTEM OF AUWERS, FOR THE EPOCH 1875.0. * , : Auwers | *Safford | Newcomb oe Be Auwers | *Safford *Boss Newcomb) NAME OF STAR. Right Ascensions minus minus minus } Declinations minus minus minus minus for 1875.0. H.C.0.| H.¢.0 | H.C. 0. for 1875.0. H.C. 0. | H.C. 0. | H.C. 0.| H.C. 0. °o ” ” ” ” . s. 8. 8. 8. i , ” 55.762 | —.002| —.012} —.0021 +28 24 0.87} —0.08} —0.03| —0.16| —0.14 49.774] +.014| +.082) ...# +45 22 34.92) +0.23/ +038) ...] ... 48.032 | +.007| +.017| +.006% +14 29 18.26] +0.29| +0.07) +0.22| +0.23 | ) AOS] SallAO sco || co eo) SE Wh Caltets)|/ PS oon | pani] ovo] 3.5384] —.0038} ...| ...-f—9 31 1.76) —0.16 Andromedze 2 Andromedse Pegasi Groom. 29 . Ceti Ceti Cassiopeiz . Cassiopeiz . Cassiopeiz . Andromede 39.591} +.000] ... 2347 — 4 38 53.81)—0.11) .../ ... 54,568 | —.008) +.009| .. . +62 14 29.33) +0.21| +0.33| +0.41 25.459 | —.003| +.049| +.039| 51 5.34) —0.17} +.0.05| —0.20 25.845| —.063| ...] ...f 18 15.37) +0.22) ...|+0.42 42.946] —.008| +.023) ... 2: 2.13 | +0.15| +0.30| +0.50 82.938] —.090|—.061] ... .22} +0.02} —0.31| +0.05 10.699} —.019| +.004) ... 12| +0.26] +0.43 | +0.43 DAO NOS 5 Ou ))| SOA Sg og ORS BPA seb SNS 6 5 al) o auc Wits =O/5G)" te a le ete 2 44.300} +.001)| +.040) —. 3 25. +017) +0.32| +0.10 | Cassiopeiz . Cassiopeie . Piscium . H. Cephei Andromedze tl a) ooococo eecoocr Piscium . ; Urs Minoris . Cassiopeiz . Ceti Piscium . 46.792] +.019} —.010| ...] 31.93] —0.40] +0.51 99591929) eae ieee DD OIEEOO a oe 7.625] +.085|—.001] .. .| 28 35.18] +0.50] +0.69] ... 46:554| +.008| .. . | —.0201 — 8 49 44.83] —0.03) .. . ||+:0.16 47.791| +.008| —.006| +.006} 2 2.89] —0.18| +0.05| +0.07 +0.45 eee ee b Persei Cassiopeiz . Piscium . Piscium . Arietis 19.726) —.010| —.052) ... | 38. +0.40) +0.27) +0.36 6.560 | —.032| —.1383| ... 146 35.17 | —0.69| —0.30| ... 55.654; —.006| ... VSSUBS3 G6 A) om 47.646) +.014) ... 0224 8 E +0.43| .../+0.14 44.268 | —.011) +.004) —.016; 72) +0.00 27) +0.11 — et et pt 37 00 ¢ Cassiopeiz . » Andromedze Arietis 8 Trianguli 55 Cassiopeie . 2) OTE) E1005) ss 48 53.934 —0.34 +0.01 96 13.980) +.013} —.038| .. . | 43 43.16) +0.33 +0.28 7.796 | +.005 say 22 52 13.38] —0.28 —0.28 NNN Re 6.625| +.098| ...) ... 9-434 23 +0.08| ... | +0.27 41.802| +.052| ....| ... .+65 56 11.37) 41.44 ue * After reduction to the system of Auwers, 408 NAME OF STAR. Right Ascensions | for 1875.0. COMPARISON Persei y Trianguli Ceti Ceti , Cassiopeiz . Ceti . H. Cassiopeiz . » Arietis 5 Ceti . Groom. 537. Persei y Ceti Arietis Persei H. Cephei Ceti Persei B Persei 6 Arietis . 48 H. Cephei . a Persei o Tauri. — Tauri. f Tauri . e Eridani . Groom. 716. 5 Persei : 5 H. Camelopardi 7 Tauri. t Persei 9 H. Camelopardi e Persei ; , Tauri. Groom. 750 Persei Eridani . » Tauri. Tauri. Tauri. Camelop. seq. . Tauri. Eridani. . Groom. 848. 7 Tauri. 4 Camelopardi bo b bo hb bo bo bo bo bo be He He He He He G9 CO CO OD CO G2 G2 GO GO OO He He He He - 8. 18.120 | bo bo bone bes 31 43.302) Dd 24.357 7 10.307 2 2 3 3 3 3 3 1 3 Ss yee’ 3 37 11.738 2 40.887|—.008| . . . 15 43.668] —.014| .. . | 21 19.156| —.007| 8. —.015 53.284| —.001 44.996 1.947 | +.005 47.572,| +.006 —.006 —,025 +.032 +.025 30.876 | 11.439 | 4.570 5.943 | 40.260 +.009 —.008 +.123 37.765 33.603 44.791 = 011 2.488 29.030 | 32.137 | —.013 24.432| +.000 5.288] +.002 93.748 +.040/ 58.403 2.513 | 19.525 1.924 +.031 } +.003 — O20) 3.388| +.005 16.690 025) 2.2 4056) .. +.024} ... A956) — 019) ee OM eke | 1008) 5.1... Bo ae OTE eel —.001| Sos eae. 29.575 28.212) —.008 3 45.394|—.004| .. | | 58.197 | +.218| 35.605 | —.049 45.850 | +.047 | 8.196| — .010 | 44.937 | 4.439) —.020| — O21 Tse OF CATALOGUES OF STARS. Safford |Newcomb minus | minus H.C. 0. | H.C. 0. +.011) ... 2.968| —.003| ... | 44.672| —.037 35.836| +.000 | Declinations for 1875.0. 29 16 09 32 50 53 16 25 12 ity¢ 48 41 42 44 14 Hi) 35 21 28 3 2 58.62 8 33.52) —1.30) 19.82 vie 285.210.2012 27. 49 31.35|+143| ... 2 47.37 | 1.74| —0.20 4.01| +0.21 58.57 | +1.67 +0.02 19.69 —0.44 54.68 9.62 | +0.31 | +0. 26 | 10.63 +0.00/ 43.50 | +0.14 29.23 | +0.25 | 3.41) —0.21 28.27 | —0.45 37.86 | —0.06 | 56.68 | +0.21 —0.72 | —0.40 +0.09) | +0.44 . Ose & oe 5|—0.07) ... 9 40.23 14.80) —0.17| 42.99 | —0.22) ... +0.02 | 40.13 | 23.98 8.41 | +0.13 38.14) —0.08 0.54 | +0.03 87.99| —0.34| .. . | 23.26 | 47.52, +0.01 7.21 | —0.06 +0.21 54.39 +0.00 25.67 | +0.03 50.74|—0.08| .. . 4.34 —0.21 12.03 | —0.59 | | 21.16 +0.36 34.76, —0.38 54.37 | —0.05 =f Mul) pete 09.38 | +0.65 .. | —0.21 . | —0.29 | —0.11} +0.23 | —0.78 | —0.73 —0.27 +0.06 40.47 | 40.21 . | —0.30| 0.01 COMPARISON OF CATALOGUES OF STARS. 409 A ‘4 Auwers Safford [Newcomb aes A § NAME OF STAR. Right CeO minus minus minus | Declinations rine mi ee for 1875.0. H. 0.0. | H.C. 0. | H.C. 0. for 1875.0. H. 0.0. | H.C.0. | H.¢.0 atop eotic di eal ee ae 84) —0.21 38.189|—.032| ... | ...1+66 7 37.48] —0.59 51.321| +.007| . . . |—.007] +32 57 57.15| —0.05 18.318|+.059] 12.) .. «| 5 29.93) 40.56 GaoT|01e|) ee oa 28) —0.21 fw Eridani . . 9 Camelopardi Hm CO eS coe t Aurigze . . 10 Camelopardi e Aurige . bo on oo 44.605|—.009| ... | ...4 58 26.92 4.0.43 37.512| +.001| |... | 4. 21 24 33.73) 0.35 59.791 TO Loa lie acne 1.16 +0.00 rere . 3 oo 5 ce | : od + 89 BOYS TO NOLDi| © eal 2.25) —0.19 ¢ Aurige . l Tauri . TORE Camelop. Eridani . Aurige . 97.430| +.003] ... | +.0004 2 5.67} —0.29 31.846) +. Sy) OTA 2.42| +.0.06 32.250|—.029/ ... | ...{1— 6 58 52.50| —0.37 23.464| —.004] ... |—.003] +28 29 58.60| —0.13 1.184] +. S| Ae |e 22.15) +0.22 Aurige . Orionis . Orionis . dthest 5 op Groom. 966. Or cr or on on Or Or Or He He He eR b Oren oes Orionis . Orionis . Orionis . Aurige . Aurige . BCP Allts}|| ete space 5 H 26 07} +0.06 2 OA | | ays 2 0| +0.86 Qe 28279) Shee il «eee E 33 +0.42 13.075 0 BS ae eee 42) —0.03 49'627)| —.025)).... Srl J} Bey +0.02 Or or Or or on 24.269) +. Sens 007 22 54.71; —0.41 21.619) —, Gey. © Bod é 55.22] +0.19 Ue! AKON)! oo 5 ll 6 oo 2 5.08} —0.03 162531! = 100)|"5 = |. 2 2 £6! 22.06) +0.03 26.113 | —. o hrc ; 4 46 52.51) +0.22 Orionis Aurige . Aurig ae Camelopar di Orionis 4.225) —.089| ... | ... 1469 21 35.80] —0.35 19.939] +. Rees 22, 32 27.46| —0.33 2a 5ILT9S)|.1 025) Seen) iF 41 37.27| —0.75 29.448 | —. ... |—.022]416 30 13.31] +0.55 14.952| +. RES a BES 5.08| —0.45 H. Camelop. Geminorum. H.Camelop. Geminorum H. Cephei . ByAtisy/|enilols) Rec guee|) haem (BE: 34.30| +0.48 26.8650) 4.008} ... | ...|+58 35 0.55| +0.12 ACTON Gr |e ale: 5.76| +0.04 2992007) oh ol) os). [ae 19.29] +0.25 20:549)/+.004|) 0.7. | 2... +e 10.31/ +0.09 Geminorum Lyncis ¢ Geminorum 63 Aurigs 64 Aurige . 54.503) +. iene 02 50.06} +0.08| ... 10} —0.26 2 39.406) —.05 artetts : f+22 12 37.26| +0.44| ... 27 | +-0.22 51.285| +.0« Scr oe | Poser 8 48 3.14) —0.35| ... 0.05} +0.06 57.687 | —. oda : 28 2 40.00) —0.20; ... -08 | —0.25 22.269} +, coal | Monee 2 21.40} +0.44) ... heh 2 Geminorum 6 Geminorum. Groom. 1308 t Geminorum 6 Canis Minoris ; Inds -I ANOS lor or Menken) 2 S2 Or On 4.164) —. Gace 019 f +32 51.89} —0.12 36.904) +. mish tl at cae SKOHUIl| 5 6 37.317} —.213] ... 37.14; +0.17 2 45.392) +. ieee 37.68 | —0.37 39.886] +. Aor 34.21) —0.01 e@ Geminorum «! Geminorum « Geminorum . @ Canis Minoris . 6 Geminorum NAA 410 NAME OF Right Ascensions for 1875.0. COMPARISON OF CATALOGUES OF STARS. Auwers | minus | H.C. 0. | Safford minus H.C. 0 Groom. 1374 Groom. 1408 B Cancti_. - . Urse Majoris . Cancri Groom. 1446 Cancri Hydre Cancri. med. Hydree Urse Majoris . % Urse Majoris . * Urse Majoris . Hydre Lyncis Cancri Lyncis H. Draconis Hydree : Urs Majoris . Groom. 1564 o Leonis Leonis 4 Ursze Majoris . Leonis Groom. 1586 Leonis 7» Leonis Leonis P . Urs Majoris . Urs Majoris . Leonis Minoris H. Draconis Leonis Pie H. Urs Majoris Leonis Minoris Leonis Br. 1508. Urse Majoris . 7 Leonis Urse Majoris . Leonis u £ Urse Maj. med. Leonis a ave Groom. 1771 Onmnnwmn 9 38 45.196 5 11.562 3 46.938 9 51.834 (oe Mo Mo 9 22.072 3 26.138} —.021 omomoooeo Nojilaile oe ole <} 3 23.723| —.018| 20 39.023 | —.009 55 59.864) +.014 34.105) —.001 al —.047 | —.012 +.016 —.044 28.689 | +.010 | 44.097 25 45.577 | —.007 | 37 34.777 | —.014 | 9.326, —.006 36.867 | +.004 | a +.025 | 38.493 | —.017 | 4.972| +.042 | == OG 51.593 | +.009 3.646| —.011 | 0.164) +.010 5.932 | —.192 26.670} +.018 | 30.803} +.023 | 28.678) +.007 —,.005 5.127} +.003 | cea +.007 | 9.765 | —.050) 53 36.405) +.004) 30.942) +.054| 42.818] —.018 33.083 +.000 52.567 | —.003 24.847 | —.052 13.699 | +.003 5.381) —.008 eter —.026 41.158; +.001 53.400} +.076 | 37.779 27.512} 30.709 41.417 | ses +.012 Newcomb minus H. C. 0. | Auwers minus H.C. 0. Declinations for 1875.0. 52.12) +0.52 4.22) +0.63 8.75| +0.13 1.39) —0.20 51.05) +0.11 +74 14 +76 8 + 9 34 +61 +20 3 49.13 | 5 43.56) 2 33.75| —0.28 3 4.97|—0.71 12.21, —0.50 —0.88 | +0.57 +74 18) + 6 +31 + 6 +48 31 50.65) +0.25 +47 38 56.81) +0.15) +67 38 23.34) —0.08 2 50 25.60, —0.20 48.21} +0.08 1.96 | 55 10.57 2 33.02 4.43 | 22 40.32 +0.34 +0.27 —0.13 —0.02 +0.29 8 17.46| 35.72 99.12 | 31.55 35 40.89 | —0.65 —0.17 +-0.26 | +0.04 | —0.44 28 20.32) 35.41 | 16.49 37.79 15.46) SETA —0.69 +0.02| +0.28 | —0.06 37.91} 49.09 | 21.29 > 56.58 | 44.91 +0.27 —0.09 —0.38 +0.32 | +0.04 24.79 2, 21.35 20.43 | 25 30.97 40.73 —0.36) +0.32 | +0.54 | 40.44, —0.04) | +0.16)} —0).06) +0.03 | —0.40 | +0.51 | 34.38 | 2 29.68 | 3 55.45 | 50.86 oboe Safford Boss minus minus H.C. 0. | H.C. 0. COMPARISON OF CATALOGUES OF STARS. 411 Auwers | Safford |Newcomb § ar Auwers | Safford Boss Newcomb NAME OF STAR. goed epee minus minus minus Declinations minus minus minus minus # ‘or 1875.0. H. C.0. | H.C. 0. | H.C. 0. f for 1875.0. H.C. 0. | H.C. 0. | H. 0.0. | H.C. 0. | - 5 " 8. 8. b ° te i us i Draconis . . |11 2% : EXD) Gace || ole 0) ee) 15,3) SOSA 6 os .69 | —0.69 | @ENueOMISh is ey 32.918} +.009| ... 4 4— 0 9.48) +-0.80) . . . .55 | +0.62 3 Draconis . . 35 29.052] +.031} ... .. » | +6 oy adalat) SECO A Soe Pereira | cect y Urse Majoris . 26.630} —.020|} ... Beoerl 8 28 20.65) +0.04) ... : Sa B Leonis .. . ; —.007} ... : ; a TN — OTe) ene 22 | —0.33 Pe VaAceInIS ey yt : =O) wana 015} 8 «8.77|/—0.85| ... 56 | —1.09 y Ursee Majoris . : ANUS oo 019} 23 23.32|—0.34| ... 46 | —0.39 o Virginis. . . : J EOP 5 oo 002; 25 38.18|+0.03|) ... } +0.02 Groom. 1852 . 3} GPA | VW og || 50 a) ERAS) hey Nees || cone one 4 H. Draconis . {12 6 19. —059| ... satel 8 40.381}—0.61; ... .85 | —0.87 mn Virginis. . .|12 1 6 —(0083}/ 6 4 6 4 40.23 +-0.29) ... .82| +0.39 x Draconis. . .|12 28 8.8 —AIPI| 50 |) oH 0} 8 39.42) —0.40) ... : —().47 y Virginis. . . 412 3: : +.059) ... .066 | 5 48.60} —0.44) ...} ... | —0.67 e Urse Majoris . j12 48 31.4 —.027 |—. Feo 5 19.03 | —0.09 Seu 12 Canum. Ven. seq, 12 : —.001|—. 004 | 89.21 | —1.36|—1. .54| —1.44 8 Draconis . . |12 50 29.640] —.020|—. ral 1.40 | —0.82 | é Virginis. . . {1% 57.266 | +.009 | +.02 peel 53.04 | +0.00 | | @ Virginis. . . {13 3 28.750);—.013) ... : 2 15.90 | —0.02 | 45 Com a 6 : 2.359) +.017)| +. ... +28 380 44.10); —0.12 } ¢ Urse Majoris pr. 13 18 53.390) —.033/+.026| .. . | 43.13| +0.07 Groom. 2001 . {13 22 56.909) 4.055) .../]... 26.95) +0.81 & Virgins). 2 3 113 19.475) +.001) ... d 37.52} +0.48 Groom. 2029. |13 11.050 | —054 42.74) +0.53] ... Urse Majoris . }13 42 36.813] +.013| eee 023 15.90} +0.11 | +0.20 Draconis . . 413 46.880 | +.028 | +.089 } +6 29.34) —0.84.|—0.88 Bootise 2. 43.963) +.019)+.017 .020 | 30.28] +0.14|—0.10 t Virginis. . : UL SEND Pee Soll! aoe os) 1.05|—0.44| ... a Draconis .. OSG 0240 Gn mene 4 58 25.99 | —0.23 | —0.23 a omit 6 oo \pe 41.899} —.014/—.004| ... | +2 4.74] +0.02|—0.21 4 Ursz Minoris . |1+¢ PTE 5 oe || 6 oe 78 8 7.23)—1.55) ... Ce DOOtInME an -nnr- 57.622] +.007)+.000 | +.008 2.19) +0.41 | +0.60 6 Bootis .. . 56.495 | —.008 | +.022 | +. 2 25 45.09} +0.14) +0.08 fy ABiorouM) 5g | [IE 26.580 | —.005|—.013 ' 15.95 | —0.37 | —0.31 y Bootis > 27 2.672) —.011}+.033 . te 21.19 | —0.23 |—0.38 ma Bootis pr. 5 oo | (ile 51.119} +.003|—.053] ... fj 18.71} —0.19|—0.15 ¢ Bootis med. . > 10.829} —031/—018) ... 5 55.82} +0.22|+0.01 Virginis. . . So) sist AOE oo Pe A sy MBH Sill Gea os Groom. 2164 . }1-4 16.196'| —.087|—.117] ... 8 9.33) +0.07 | +0.62 6 Urs Minoris . 5.463 |—.042} ...] 2... 58.64) +0126)... 2 H. Urs Minoris 86.145 | —.018/+.084]) ... 50.71! +0.25 | +0.26 Bootis . . . |i# —.001|—.015 | —. 3 4.87) +0.03|+0.15 Bootis) 2.) +.012)/4+.016} ... y 9.64 | +0.19 | +0.10 Brliibrals 7). ) =e ONS /iee tees : : 1312) —0:05)) 2... 6 Bootis . . —.002)+.086) ... : 55.11 | +0.93|+1.05 1 H. Ursee Minoris 15 131 —.054/—.028| ... a eae 412 COMPARISON OF CATALOGUES OF STARS. . A Auwers | Safford | Newcomb ake Auwers Safford Boss NAME OF STAR. Right Ascensions minus minus minus Declinations minus minus minus for 1875.0. H. C. 0. | H. 0.0. | H.C. 0. for 1875.0. H.C. 0. | H.C.0.| H C.0. 7 “" ” y Ursze Minoris . y .025| +.035 . ++ +72 16 43.69) +0.09 +0.04 B Corone. . - 2: E +.009 Wells 32 15.80) —0.34 —0.50 » Bootis pr. . 26 26.389) +.018 aes Al 15 36.32) +-0.04 +0.25 vy Bootis seq... 18.530) —.004 sePA)) 19 28.12) +0.06 +0.14 @_Coronsesn ee 23.760 | —.001 ae j 8 11.61} —0.08 —0.10 a Serpentis . . {lt 6.693 | +.018 020 AQ 12.71} +0.02| .. .|—0.02 6 Serpentis. : 25.143 | —.005 ees -dopaeb2-46)|— Osi : —0.64 fe Serpentis . . 3 5.840} +.034 eli evremee See AIS ee OIO mean | eee e Serpentis . . {Ie SOuZ8 —EtOLO I is 0345 51 18.37) +0.95| ... | +1.07 ¢ Urse Minoris . 48 33.866) —.078) ...]| ... 10 40.64; +0.26| ...|+0.25 Serpentis . . 40.791 | —.036 ere 4 15.85) —0.43 | eis Groom. 2296 . {1 49.547 | +.018 ke Bo 12.94 | —0.05 +0.12 | Draconis . . {1 32.928] +.093 SOs Li—OOL —0.06 Ophiuchi . . |16 47.778 | —.008 H— 3 22 15.05| —0.10| —0.16 Ophinchy 16 ATO — 1006) eee eae 23 9.94) —0.61| . ee Urs Minoris . 24.796|—.027| ...| ... 29.15 | —0.14 pass Herculis;.) 5 24.387) —011}—.008| ... > 52.53) +0.30 +0.67 Hereulis. . . 116 19 38.875) —.012| —.030] ...} 20.76) +0.06 ee Draconis . . 116 2: 18.077} +.141} +.120} ...] 50.90) +0.09 +0.27 Ophiuchi . ./16 24 36.598}—.008| ... A+ : 32.40| +0.04) ... | +0.06 Draconis . . 16 28 14.132] —.056|—.038| .. . | 18.79) +0.06, —0.41 Groom. 2373 . 309 2:925)) 083i) tee) + 3 el 37.95 | +0.23 | 5.0.0 | Hereulis . 34.482) +.015| +.061) ... 49.46) —0.08. —0.02 Hereulis . . 38 36.681) +.020) +.029) —.02648 +: 39.75) +0.26 +0.11 Groom. 2377 . 2 55.637) +.093/+.075| .. . | 21.30) —0.33 | —0.28 Hereulis. . . 23.436| +.009|—.018| ... ; 8.14] —0.44| cro Ophiuchi . . 45.127 | (0 (45) mcs [ar 15.05) +0.15 | +0.21 Hereulis. . . 30.467) —.002) +.007| ... 41.99 —0.04, +0.15 Urse Minoris . OOMSO EOD ee ce ace 8: 22.45} +0.26 | +0.16 Groom. 2415 . 3 42.190] —.047| —.057| ... Q —0.29 ates Herculis. . . 56.918 | —.018 | —.016} —. ; 05 | —0.04 +0.23 Hereulise ome 41 65/(G)/—Olsi 031) snot ; —0.28 | —0.50 6 Draconis . . 27 36.553| +-.019] +.016] +. | 2 .69 |) +0.10 —0.12 Ophiuchi . . S 7.953 | +.002| +.002] +.0034 +15 L —0.19 | —0.12 Draconis . . 32 27.990} +.002)—.003|} .. .} 2 52.26) —0.14 secre Draconis . . 41.045] +.068] +.053] .. . | +65 68) +0.10 +0.15 Elereulisiey) 34.009} +.037 | +.022| +.0384§ +27 j +0.36 +0.42 Drac. Aust... é 9:890)| 007i eeese| ce dene .52| —0.02 —0.17 Draconis . . 3 42.247 | —.003| +.056| —.008 5 84! +0.05 “elas Draconis . . Om 280742023) eae ela eee +0.32 . . | +0.66 Hereulis. . «1 40.039] —.012] —.027] ... 4 +5 : .71| +0.06 —0.22 } Urs Minoris . 2) 39.224) =1039)) =. | ae aglee8G 43| +0.29) . +0.28 7 Serpentis . . ]1! 90% 42) 0145 eee +0.05 +0.40 Mercnlis;. 5) 21/18 822299774) 01 081) eee y y : —0.20 ae Draconis . .{18 22 4.979] +.099] +.062] ... 42, +0.55 +0.85 COMPARISON OF CATALOGUES OF STARS. 413 5 . Auvwers Safford | Newcomb ee Auwers Safford NAME OF STAR. Right Ascensions minus minus minus Declinations minus minus minus for 1875.0. H.C. 0. | H. 0.0. | H.C. 0. for 1875.0. H.C. 0. | H.C.0.| H.C. 0.| H.C. 0 . 8s. 8. g Draconis. . 32.856| +.052 y Draconis . . 18.569) —.027 a Lyre. . . . 418 32 42.392] +.003 Groom. 2655 . 35 46.483) +.125 Herculis. . . 16.926 | +.0383 3} IDNA oh oD 27.840} +.086 1S5R: byrne. «. 31.927 | —.026 e Aquile .. . 56.953 | +.029 G Aguile. . - 39.911) —.011 wo Aquile . . . 56.967 | —.004 6 Draconis .. 31.835] —.046 3 (hye GBS 12.809} +.018 Draconis . . 56.730) +.002 j Aquile . .. 11.757 | —.006 Cygni = = 40.851] —.007 Groom. 2900 . 13.082] —.156 y Aquile . .. 19.016} +.000 6 Sagitte . . . {19 48.870] —.023 a Aquile ... 44 41.054) +.007 m Aquile ... 6.300} —.012 e Draconis . . 35.280] —.046 B Aquile . .. 10.392 | —.009 2d Urs Minoris . 49 16.178) +.635 @ Aquile . . . {% 51.302 | —.023 x Cephei . . y 3.809 | —.036 7? (Oyen oo ol 44.553} +.029 é Delphini. . . 14.456] +.012 6 Delphini . § 41.232) +.014 73 Draconis . 7.956 | +.116 o@ Delphini. . 49.954) —.025 a Cygoni .. 10.278] +.005 g Ove oo 4 6 9.233 | +.022 me@ephel ~ . s 44.656} +.015 p32 Vulpecule. . 14.003 | +.013 76 Draconis . 30.604} +.075 » Cygni. . 30.864 | —.022 Brvziag. 3 11.574) —.022 61 Cygnipr. .. 17.727 | —.041 € Cygni. . 37.046 | —.034 77 Draconis . 57.570 | —.011 TAC youl eels 48.153 | —.009 a Cephei... 35.688 | +.020 B Aquarii . . .|21 24 58.685) —.021 BCephei an cpr. 2.444! +.013 3.9! a yay 5 6s 2.801| +.014 18 10.05 VOL. X. 53 414 COMPARISON OF CATALOGUES OF STARS. ih = A Safford |Newcomb Declinati Auwers Boss Newcomb NAME OF STAR. Right Ascensions minus minus aaa Et minus minus minus for 1875.0. H.C. 0. | H.C. 0. | H.C. 0. for 1875.0. H. C. 0. H.C. 0. | H.C. 0. | 11 Cephei . . .|21 40 5.015] +.018 .. »f+70 44 10.41] —0.14 —0.26| —0.27 | jm Cygni . . . |21 42 10.618] —.003 . . «| 448 43 55.08] —0.77 i ae 16 Pegasi . . . [21 47 22.554! —.014 +25 20 16.00| —0.25 059 oo « Aquarii . . . [21 59 21.787) +.007 — 0 55 35.66] 40.78 +0.76| +0.83 | « Pegasi . . . {22 1 11.580| +.000 }+24 44 6.35] 40.35 HOG) Sa 6 Pegasi . . . [2% 53!663)| +00 re |) oe ate 1.45 | —0.63 Sie } C¢ Cephei. . . |22 31.177 | —.011)|—. . 2 sf +57 7.94| +0.04 +0.02 | 24 Cephei . . . {i 24.018} +.010) ... 3 32.89) —0.19 eta pec-crs | Aquarii . . . 422 14.195} +.033] ... 24 18.28] +0.35|} ... | +0.15] +0.13 Aquarii . . . 42: 11.969) +.004) ... 59.97} +0.28] ...|+0.51) ... 38.856 | —.023 | —. anrinig 11.68} —0.01 oteae 8.684) —.011 | +. 38 25.37 | —0.46 —0.34) ... 55.965| +.006| ... 40.96) +0.44] .. +0.54] +0.61 2 40.788} +.077| ... y 40.33 | +0.15 Ppstcn| | eee 13.683 | +.018 | —. 45.28) +0.11 +0.30| +0.30 Lacerte . Lacerte . , Aquaril . Cephei Pegasi bo bo bo be to bo bo bo bo bo 8.684| +-.001)+.002} ... 4.92 | —0.34 —0.53 3 Lacerte . 81.173] —.001/+. Tea 48.56 | +0.08 ee , Pegasi Sake 30.709| —.006|—.033 | ... 2% 29.82| +0.03 —0,15 p Pegasi . . . 122 43 58.291) +.011)—.( Age 2 30.86} +0.10 SENOAN Td Cephei . . . [23 14.069} +.026 | +.0: Ewane 3) 32 35.76| —0.14 —0.09 | —0.09 7 Pegasi bo bo bo bo bo bo | Aquarii . . . |2: 5.560!—.015| ... B 39.89 | +0.15 +0.47 | +0.44 Andromede . }22 56 10.396) —.004|—. 15.49 +0.61 +0.23] ... Pegasi . . . 2: 32.139 | —.023 | —.03% 59.06 —0.12 —0,.23}| —0.24 Cephei . . . | 55.647 | —.047| ... 2 42.33, +0.62] . aero | etx Aac » Pisclum. . . }2: 41.157; —.086| ... : DS 740-38) areal eed oe Pegasi . . . 27.114| —.001] +. bs) Se? 22.78| —0.17 Pegasi . . . 12! 8.428| +.096/+.129| ... +22 42 58.14) —0.17| ee 2 Andromede . {23 31 27.068| +.029|+. .. «1445 46 50.86] +0.53 L096 | see Piscium. . . |: 31.311|—.021] ... | —.022}+4 4 56 56.72| —0.93 | —0.71| —0.66 » Cephei . . . |2: —013| ... | ....+76 56 4.98]—0.13] .. . | +0.01| —0.01 H. Cephei . . | ; 065i —-Osoa|) eas 44.11| +0.38 +0.14 Pegasi . . . (2: 827) +.013)+-.009} ... 5 33.62| +0.04 ats Cassiopeize . . |: 799} +.013] +. , > 48 13.48) +0.20 Piscium . 2.2 [23 52)58-570\ 4.013 | 16.65| —0.19 —0.36 CATALOGUE OF 284 SECONDARY STARS OBSERVED DURING THE YEARS 1871. 1872, 1874, AND 1875, WITH THE MERIDIAN CIRCLE OF HARVARD COLLEGE OBSERVATORY, AND REDUCED TO THE FUNDAMENTAL SYSTEM OF AUWERS, © FOR THE EPOCH 1875.0. : . Auwers Safford | Newcomb See Auwers Safford Boss Newcomb NAME OF STAR. Right Ascensions minus minus minus Declinations minus minus minus minus for 1875.0. H, C.0. | H.C. 0.| H.C. 0. for 1875.0. H.C. 0. | H.C. 0. | H.C 0. | H.C.0. 8. 8. ° ¢ uy ui Ud ue i SPAR Gol oo all od .|(S> 6 TION oo ol] oc 10 33.981] ...|—.092} ...§ +87 59 15.20} ...|—0.10 TE) oe 6 || 6 al} o 65) (28) 40 PAO) soe] oot 17 54521). 2. | 11024). 2. f-F6l 8 17.10) =~ - | --0:36 PL AGMAMI Go ol] a 4c oo) Ale 13) |r |ieen =) 8. 8. 5 Piscium . 0 Andromedze t Sculptoris 2 Cassiopeie . Piazzi 0.79 . Piazzi, 0.130 30 55.865] ... .. .f—25 27 19.41 E Cassiopeix . 35 61005) 2. | 1052) ene edo) 49) aG.90 |) 28 || 0)ee| ene ene B Ceti 18.928| —.053 —.056] —18 40 23.06| —0.79 ~0.74| —0.75 y Andromedze 42 DO.091| 5 Baht (NN 5 5 5 PASE) BB) Balto) G6 og |) sHUEaS) Peper Piazzi, 0.207 44 52.164 5 8 6 | HOI) (aS By OIE 5 A oul co a 6 —0.75 20 Ceti « Sculptoris uw Cassiopeiz . 7 Ceti o Andromedze AS BPR oo el] 60 0) ON = a JO Ba alO] 6501) oo 0] 4 2 o|) SHOua) SSS) cota oe | coc || oo el|—e) VUE Go all Go all ove] oe 59 58.182) ...|—.181) ...§+54 18 21.58] .. .|—0.12 il (PAID Teoka'i| o°c 0] ono ©) (es BI) SEH 6 oro |} cova’ 20 11.101) ...|/+.008] ...9+44 45 37.14) .../+0.14 SSooo (Soom oo ococmes SU) ~I 38 Cassiopeie . 1 21 57.489) ...|+.010) ...§+69 37 13.52) ... | —0.45) —0.53 Piazzi, 1.109 1 OE PAGO 6 Goll 6 6 all om 0 | [eur CL) PAS) Bo ol o.oo |] oe z Andromede .| 1 33 12.470) ...|+.048| ...]+89 56 34.65] .. . | +0.57 PiazziykadiO) s |) i 4 16:704) 2 \\—091)| 55 = |)-F37 19) 45:96). COs x Ceti 1 43 26.802 ae BY aaa RANG GS all 25-5 f Ceti TL AS AG OOS ge ol) 5 6 0 | faa) tier Heil OBI] 5 5c ae 2 Arvietis pr. . TSOP SS COON ee oll O35i) eee eke 220 59) 40) n ce i — Ono: Mitac v Ceti 1 54 6:932)—006] . 2.) ...§—21 41 4.62)|—O11) 3. Ewe 27 Arietis AGRI so 5) oo 5 PSEUBB hil By tee] 6 oe +0.35 o Ceti DED Gee Ohi O2!| Meee cull teeen | cere —Lo, 40 20102 wane 7 Eridani . DCE UGA gs Sh) ole oll cece] fat) Gael” 6racn 12 Eridani . Be Ge45e7l||= 1005) veer ellen et ei f= 2928 Ol 6/0389 ¢ Eridani . By 8) ZeysBi) soc = Olu Ta mies O)|(aeeareite x Ceti F a AIA Ae ll acuenl| epeenl (ee ene ey eilalle gaan 6 Eridani . 3 37 15.689] —.024) ...| ...{—10 11 18.20] +0.81 416 COMPARISON OF CATALOGUES OF STARS. | Right Ascensions Rowers || GR | Newcomb Declinations ee | Eaton oes Nepeoray AME OF STAR. Seinen minus minus minus att minus minus minus minus sien for 1875.0. H.C. 0. | H.C. 0. | H.C. 0. for 1875.0. | 0.0. | H.C.0. | H.C. 0.| H.C. 0. | | Si =) zm 7 eo al ” ” ” ” af iby a os AD AT AVS) Soe) ois, ol) ee ee. I A8299 aii ghana Piazzi, III. 183 7 Ba ees a oll Gaol) 6 oa feasts US EGRH) ao. Sin seaee y Eridani . 52 11.913 | —.035|} ...|—.015}—13 51 55.91) —0.57| .. . | —0.57| —0.58 2 Persei 587 16.729 52 +50 0 34.28) ...|] .../|+0.27 Piazzi, III. 249. 60,047 2.) cc VOSS dy @ dace erties) ene co 0 o-!nm wr p Tauri. } o? Eridani . ) 64 Tauri. v®? Eridani . } 80 Tauri . ge: Slee cess! ace oy fereloe ed OR SOOM ven ast || ew yen eed —— UG OL OBEN ME Sopa ll ceo al a ced lacie ON eas] PAVT DD areas |) cecmrnl ice chy FIR Gs oie Sal) oS oll aos : 46.53) ... pee | arce ee | fat Si) RH OPH Oo co eo wo oR eRe ) Cc oO a f=} Oo or 1 So i=) bo -$ — o bo | el 85 Tauri. 2443-4351 202i ce + | 0461-215 3452-50) Se a 2 - oil eee Osce couleur. 26° 45:372))" 2.25, || aes || 0820-4 Sa AG AGP ee. ec ale een o-0e 53 Eridani . 32 27.381 -. -1—14 32 59.80 ene m® Orionis . AEBS 20 cicinsn || ie wey ueketell ston ee OeoL o' Orionis . ADP OTTON ae. eart Sy ro| EE ait) » Leporis . 5 14 11.033 —12 26 44.28 m Orionis 5 16 15.865 + .3 25 20.19 Orionis By 20) MON ecco crete dl) vote. SUP RDOE UTED wok eee coe eal eee mre « Leporis . 5 27 13.041} +.001| ...|+.010]—17 54 47.62) —0.94| ... | —1.00} —1.00 ¢ Leporis . 5 41 17.492} +.023 .. -f—l4 52 13.32] +0.44] pera (econce) _ [or] oo oo = is) 5 hk iv) qr iss co = 22) t +1.28 y Columbee ren Orionis . . . Piazzi, V. 327 . 6 Columb 6 Columbze 7 fas Bupa) os ES aS og ee ty $ 14448). |) 22 | Ss ae age uo p 925.480 20. | aay | he oR IOS TAD ae 17 11.693| +.024| ...| ...[—17 53 48.93] +0.06 19 AUSG4) OLS. a 2 es S03 | overanl Baie tec ete 21 32.455) ...| ... |—015}+20 17 20.48) ...|) .../ ...| +019 3 32.083 Se FP B2IB0. OUOG)) Saal (kev eu leone eaheeneme k Orionis ° 6 Canis Majoris . Piazzi, VI. 110 » Geminorum 2 Canis Majoris . ZG MMOsHODIh reeewen | want vee his a) 20) 2OMTE 26 BB298N Fe tl peat ...)—ol 56 20.71 33 59.096) ...] 2...) ...7+44 38 30.66) 13 Monocerotis . Piazzi, VI. 164 * Aurige . 3 @ Canis Majoris . yw’ Aurige . Or (=?) I lor) o : .. | ...f—24 1 45.73} Canis Majoris . 48 j : Paha Sota || oa anu! o.sec 53 42.841|—.047| .. . | —025]—28 48 12.42) —0.19| .. . | —0.48| —0.47 58 5 3 5 é Canis Majoris . y Canis Majoris . 6 Canis Majoris . 2 Monocerotis 6.207 |'=2085| Facl tas —10 2700s] O25 ee ce ee eee 18.546|—.008} .. . |—.014]—26 11 47.58] +0.84| .. . | 41.05] 41.07 AWATIAA DH DAA D lor Ror Ror Ror kor SD ororgrcn 2 bo _ oo ; 66 Aurige . : } 7 Canis Majoris . 6 Canis Minoris . | o Geminorum # 26 Monocerotis ssa 1 bo oO on —) ) 1 _ + ay l bo —_— on i for) (or) ee COMPARISON OF CATALOGUES OF STARS. A117 5 ; Auwers | Safford i ua Auwers | Safford Boss Newcomb NAME OF STAR. Right ae minus minus inus Declinations minus minus minus minus H. C. for 1875.0. H. C. 0. | H.C. 0. | H.C. 0. for 1875.0. H.C. 0. | H.C. 0. . 8. 5 ls . \ TBSP B66 || a 016i) 6 0 o|: 15 2 63.393)) 25.) 2... ||... §—2b 37 50.698 no 2 f 20.865 13.211 4 Navis. o Navis. Geminorum H. Urs arose Navis. 00 co 4-1 17 DADO | Re ce eu| eb ces 22.62 35.207 | +. eet baci 46.93 PATA eieieilio p onlten oy | EPC ceeEKey) BESCO les atl tran nal 13.73 Tes Nea ai eel eer 4.85 ¢ Caneri pr. 20 Navis. w Navis. .. B. A.C. 2846 . B. A. C. 2887 . Hydre Hydree Cancri Hydree Lyncis WAAL! Sokol balllsct.c'o. || 6 ceo 18.45 CHO soni ane | ooo) 4 Guile SHOE 5 oe |] 6 60 : i 59.47 AEN] 5 6 ol] Go o |} o oo] 53.04 BEHUPI! coo loon || cox : 24.46 [o oo oe elo ee 2) 0 ole oe oko oko 2) Cancri Piazzi IIL. "265 WEN 6 Piazzi, LX. 63. Lyncis BB DIDI) ala | kare He ORaN 11.54 BBGTGlescetloct tua ee 21 18.66 BRDTD ine es eee ml ame 22.72 RU) wie lek eel ceo ewan CMC: Pe hae iia ees 59.08 DS. O90 Navi M eee Ie nal 34 35.74 DHBTS| ae ales A025 32.78 SEB DiBOU lean sea Slee aoe 50.43 ARSC Se 2 ie rok ernie 28.48 CE) ene ee ee fess Oy ser OT) Hydree Leonis . Urse 1 Majori is . B. A. C. 3398 . B. A. C. 3428 . coco OO Oooo wo Hydra) 3 BA a0 |) 5 oc || oo 0 35.23 IBivehes 6 6 29.676} +. Bat || “Oban 14.78 2 Urs Majoris . NIT) ooo lao | coe) 3 51.18 2 Sextantis . . MEG oo oll 606 || 60.0 26 44.29 Leonis pr. . . 3 EGA oc || oo % 0334 +2 22.93 Antlie . . . WORM a oto | eae Pope 1.55 Antlie! . . . 21 25.996) +.088| ...] ...] 56.21 Jheonisy 5): UGS 6 /o || 6 ac : 47.61 g Hydre . 7 VID] 55 0 || ooo |] coo] 42.19 H. Ursee Majoris| MEAD Soa|lcoo | cae 37.11 Wh@NED 5 9 c ATOM Reese dlumcuater|| esuaceh 18.63 Urs Majoris . } ASW 6 cia lo 60 |) 65 e4 ees 17.38 Leonis . SP EXON ee cea ceo te IN: Begac 2 56.99 Piazzi, X. 199 . BBM 6 6 oll oe 6 One 5 27 59.93 Crateris Aor AVABA Sree ile, ee Bes if 0.74 Teonis; . . . Si GSGil an cmeullltenc Fett Bieileies B Crateris. . . 30.698) —. vives aes 2 38.97 iy Wether ny Oey el i a sae B 20.11 6 Crateris': . 3 5.540] —. gts was 8.43 ANGraterige.) s))\: MOREA, AS GS Al 6 sg Stee 36.62 418 NAME OF STAR. Crateris . Leonis Hydre .. . B. A. C. 3934 . B. A. C. 3978 . rare 6 Virginis . H 67 Urs ee 5 « Corvi. 5 e Corvi. y Corvi. 12 Comz £13 Comex 15 Comz Corvi. Corvi. 6 7] B Corvi. Ff Virginis . zy Virginis . 65 B. Canum 35 Virginis . 31 Comex 36 Comex 14 Canum Venat.. 11 H.CanumVenat. 63 Virginis . « Virginis . 70 Virginis . 4 BeAaG 4515) - 25 Canum Venat.. m Virginis . 83 Virginis . 7 Virginis . h Centauri. 9 Bootis 6 Centauri. 14 Bootis 2 Virginis. . Piazzi, XIV. 53 Delibtse. % =. B. AS C. A797 . . 5 Urse Minoris . Piazzi, XIV.135 Bootis seq. « Libre — Bootis ind COMPARISON OF CATALOGUES OF STARS. Right Ascensions Auwers Seflord Speen’ Declinations atwers | for 1875.0. H. C.0. | H.C.0. | H.C.0. for 1875.0. H.C.0 h. m. s. j s. 8. | Rg h ° , ” ” | 1i 18 38.318| —.018 .. . |-16 59 52.29] +0.01 11 21 30.525] ... —.012] + 8 32 40.71] ... 11 26 51.362| +.052 ..+7—81 9 58.96] +0.15 11 28 25.218] ... 39:10 10:86) ..)--. 11 36 59.828 +42 24 57.60 11 53 32.767 | . |—.008]4+ 4 21 5.77 11 55 45.722| . . «1443 44 20.00! 12 1 58.146] ... | +.023]—24 1 54.60] ...| 12 3 41.896| +.009| |... | —21 55 29.30] +0.57 12 9 22.781] —.003| . | 4.004] —16 50 51.83] —0.51| | 12 16 13.233 . | —.061 | +26 32 24.01) ... | 1218 2173} . | —.005 | TO6AT BITE 2 a) 12 20 42.368) ... | —:020! +28 57 48.02] .. 12 23 23.870| +.064| ... —15 49 9.28] —0.75| 12 25 37.770, a —15 30 12.32] .. 12 27 49.432} —.029 +.003] —22 42 19.00] 0.39 12 ps 21.095 &, 00505. & SHbOl se | 12 32 47.728 | ee al 007 T= 7 18-9806 12 39 15.169 | —.064 +46 7 26.22 12 41 29.545 | a Jet] + 4 15 19.96 | | | 12 45 36.518 | +.011 | 498°48 1680) 22 iH 12 52 44.524 —,.007 418 & iA 12 59 53.650) 4.057 +36 28 5.58 : be ale +.012 | +40 48 54.74 13 16 19.54 eae | 1-17 4 47.75| | | | } 18 18 36.591) —.026 |_o19] =10 30 29.41| —0.55 13 22 19.025] ... |—.023] .. . [414 96 50.67| ... 13 24 56.634] || | |—109| 424 52 56.84] ... 13 31 ld . | +.133 | +36 55 52.15} 13 35 3.208 tree = "8 “aa 13 37 45.310 | «+. |+.082[—15 32 58.09 - - uy —.012]—17 13 59.76 ‘ 6 ele SSeS ast 13 50 51.737 —.014 428 6 20.82) 13 59 19.940 ye —35 45 16.55 14 8 4.528 +.040| ...[413 32 48.54 14 12 20.902) al) 2 ak | DIR 19 47 Anas 14 14 50.584 .. . | —84 12 53.15 14 16 42.215 S. 4 |= ObIT1 11 18 Ses 14 23 5.901 +.011 | . 1436 45 24.82 14 27 48.789 47615 6.16 14 32 24.151 Pe Pee) lie ia 14 39 31.672] ...|+0.04| +.0471497 36 7.28] ... 14 43 57.936) 4.011) .. . | +.000]—15 31 16.27) —0.01 14 45 - | +0.26| ...]+19 37 13.17) ... 37.408 | Safford Boss Newcomb H.C.0. |G. 0.|HC.0 | 0.94 —0.95 | —1.03 | +£0.63 eu 1.12 4.0.23 | —0.41 +0.62 +a. | 044 00 cae ll a ee? EK +0.29 rae = O46) 2. 42 EGI0B | at =.39|\ > < —0.12) +0.68 ole +. 5 | 064064 | tel eae —0.31| —0.21 | 30:54] of Sa —1.52 3 +0.15 40.12 eet Sie) the Se cm —0.09 oe | +4011 +0.47 de fee | 2008 4'0.36| +.0.51| +0.52 3. | H0a0) 0a 4.030) /_5 salen NAME OF STAR. COMPARISON OF CATALOGUES OF STARS. Auwers minus H.C. O. | Right Ascensions for 1875.0. Safford Newcomb minus | minus H.C. 0. | H.C, 0. Auwers minus H.C. 0. Declinations for 1875.0. Safford minus | | | H.C. 0.| H.C. 0. Boss minus & Libre e Bootis « Libre 25 Libre. F B:A..G: 5009 : é Libre w' Lupi . w? Lupi . 2 Libre 8 Scorpii 6 Scorpii pr. . z Herculis . vy Scorpii seq.. . Groombr. 2320 « Scorpii t Scorpii ¢ Ophiuchi 24 Scorpii « Ophiuchi 7 Ophiuchi B. A. C. 5804 . 6 Ophiuchi w Herculis. 44 Ophiuchi v Scorpii 2 Scorpii w Ophiuchi 58 Ophiuchi 3 Sagittarii . . Piazzi, XVII. 289 89 Herculis . y Sagittarli . . Piazzi, XVII. 359 we Sagittarii y Sagittarii 6 Sagittarii .. B. A. C. 6318 . 1 Aguile ZEA GUUBS anes B. A. C. 6419 . o Sagittarii 6 Lyre . 50 Draconis. g Aquile z Sagittarii 8. Ha Po or, — Tl oor DO ee =1 00 bo G bo OD bo ae —) bo ~I oe 7 25.469 49.871 | 43.339 | 4.797 56.639 4.044 8 10. =a $083) 2 26.051 43.942 59.338 . 44.718 | +.006 6.183 | ) 16.637 —019 | 20.725 5.642 : 12.617 +000) 7.074 + 20.042 D9 59.022 | 8 44.258 | 2 15.985 —004 Tout 3.039 56.422 | 41.588) 0.724 22.659 | 46.723 ) 10.034 17.332 10.225 59.470 9 58.998 98 24. 346 25.778 55.517 30.815 | 21.634 23.936 19.524 2 19. = —.007 +.026 d . | 071 : Ms 8. rer 25.00 3.39 32.45 4.19) 17.49) 8.19 | 27.20 7 29.7 he ed +0.21 41.90 | —0.09 2 52.12 2.60 22.24 9.74| 0.23 | 7 16.66 8 43.87 53.48 | 2 21.81 +£0.00 5.31 | ~0.26 | G00) 2 2 21.79 —0.17 46.00 29.81 | 38.91 37.83 26.32 13.52 61.34 37.13 EG, BPAlh ore 3.80 —0.32 “ee 22.56 49.63 £0.17 46.76 58.91 9 46.25 12.31 4.90 | 59.04 59.44 | 7.87 2 40.57 | 3 14.31 | 2048 | | —0.05 4.0.05 +£0.33 —0.10, +0.48 | —0.15 ~0.05| 7| +0.02| —0.71| —0.70 —0.09 40.86 420 NAME OF STAR. Piazzi, XIX. 4. y Sagittarii : d Sagittarii y Sagittarii pr. 4 Cygni i‘ Sagittarii A? Sagittarii x Aquilie . Sagitte . . . Bike ©. Gist. Sagitte .. Piazzi, XIX. 243 C Sagitte . e Draconis B. A. C. 6924 . Vulpecule . Aquile Capricorni . 2 Capricorni . 6 Capricorni . B. A. C. 7008 . ma Capricorni . o Capricorni . 41 Cygni ¢ Delphini. Groom. 3241 uw Aquarii . Piagzi, XX. 4: 29(seq)? ‘ n Capricorni . y Equulei . o Cygni 6 Capricorni . go Cygni € Aquarii . . y Capricorni . Capricorni . 5 Capricorni . 14 Pegasi w Capricorni . . Piazzi, X XI. 336|2 13 Cephei | 79 Draconis n Piscis Austr. o Aquarii . 1 H. Lacerte . COMPARISON OF CATALOGUES OF STARS. Right Ascensions for 1875.0. . 8. 59.898 52.529 ) 19.276 40.054 39.051 26.225 5.960 10.022 37.915 26.425 26.123 | 2.579 25.747 8.911 2 31.001 6 46.214 3 29.595 | 0 43.139] 7.084 | 59.260, 5 43.451 9.908 43.770| 17.349 | 27.845 | 31.863 | 54.693 29.921 17.378 15.767 2 30.470 35.596 | 29 16.847 5.817 | 9.835 40.593 | 8.418 18.994 | 5 28.815 54.419 41.170 18.660 | 39.148 | 6B 50.952 | 30 948 | Auwers minus H.C. 0. | Safford | Newcomb minus | minus H.C. 0. | H.C. 0. Declinations for 1875.0. H.C. 0. 8. —.038 | +.006 | —.028 94 5 —19 = +36 =A =F =) +16 +63 Me 3 49 28 17.03} 55 58 7 13 32.48 51 28 10 44 4 59 9 2 18 10 9 11 12 5 35.10) Auwers minus 49.33 | 12.60 24.79 59.75 5.38 | 27.29 7.86 13.34 59.39 | 23.13 15.79| 28.83 | 47.16) 50.22 24.62 4.62) 34.97 51.99 28.54, 36.13 12.33 | 31.35 9.58 39.01 29.32 4.10 38.28 52.77 45.01 17.31 2.23 23.78 | 49.18 | 5.92 36.70 | 20.83 25.50 11.11 39.95 9.95 29.27 42.90 4012 —0.87| - | +0.25 +0.92 +£0.04 | 40.10 42.55 | —0.41 +0.64 —0.04 COMPARISON OF CATALOGUES OF STARS. 42] 5 2 Auwers Safford | Newcomb 3 , Auwers Safford Boss Newcomb NAME OF STAR. Right Ascensions minus minus minus Declinations minus minus minus minus for 1875.0. H. 0.0. | H.C. 0.| H.C. 0. for 1875.0. H.C. 0, | H.C. 0. | H.C. 0. | H. 0.0. +.010 74d W380) Go oi) Goo ao o |) oellty! eee : 57.01) ... | +0.04 —.027 36.65 gal oat 32.91 11.36 8. ia bo bo bo bo bee PAQUATIU sehr: B. A. C. 7808 . ma Aquarii . : ¢ Aquarii med. . 6 Piscis Austr. +£0.80] £0.79 IIIS 226 B. Cephei e Piscis Austr. 6 Aquarii . a Piscis Austr. . Piazzi, XXII. 262 PO)! 6 6 ol! 6 05 || aRiyanl 41 42.81 510. dl, occ ) 6.96 shag chil eremreete 3.02 ... | —0.35 54.46 bo bo bo bo b> bo bo bo bo bo 55 Pegast . . . {2: 42.481 svfoe al|t Abas 4.00 ce Aquarii . . .{|23 2 46.808 ee ’y on ln Zavnlet 2.93 |G) deter 6 6 6 | BR 95.571 oy spall) aoe : 29.32 Aquarii . . . |2: SOG DO sy sees lh maureen lll teres 33 OHlBy ANGTLENHI 5 6 on BY IP aes BS a || ooo : 89.49 Cage « ¢ 5 {28s IB SEO oo « a taue Dona OL aes +0.31 Aquarii . . . 4123 16 24928)... Baste BisHaPal; 4 oc aig IPG 6 5 6 PBF PAL BHT) 5 on |] oc i BEG! G6 oo |) oo o | Weyl ANGE G 5 a |B A ZY Ao] cb ell cae p 19.16 Pm lege ca Adxolhxoavaeks 5 2B OR BOSH 4 oo || coll ooo 89 32 49.88 Aquarili. . ./|23 37 43.014) ... Jukes 8 14.19 w Andromede . {23 39 50.685 .. . 7 +45 48 34.22 6 Sculptoris . . }23 42 24.703 tbe 17.03 Piazzi, XXIII. 204]23 44 8.080 eh 38.07 ae Groom. 4163 . }25 AG O9ieeaealiee so o | [SE 4 BILE 5 6 3 41.29 Piazzi, XXIII. 237] 22 50956)|eee Sareea 36.81 BOMPiscium. . «128 55321926) |. 029} 42 32.08 DE Cetin eat ae en | PRO ESTO) eeeiee cll let tle remotes 55.09 OOMEISCIUIME A wane NAPPA Ala oll poo d 24.93 It will be seen that the deviations of the positions of both the Primary and the Secondary catalogues from the system of Auwers are well distributed, whatever the extent or the order of the combination of the residuals which may be chosen. This distribution is not quite so well effected in the comparisons with Safford, Boss, and Newcomb; first, because it is based upon a less number of stars, and second, because it involves the determination of the systematic relation between three catalogues instead of two. These relations are exhibited in the following tables: — VOI exe 54 429 COMPARISON OF CATALOGUES OF STARS. RESIDUALS ARRANGED IN THE ORDER OF RIGHT ASCENSION. All the stars between —10° and +60° declination are included in this comparison except 7 Cassio- peiz, @ Draconis, 7 Draconis, Groombridge 2377, and 4 Draconis. Primary CATALOGUE. Aa Auwers minus H, C. sl Safford minus H. C. 0. [Newcomb minus H CU, 0. Auwers minus H. C. O.] Safford minus H C. O. | Newcomb minus H. C.O 8. 18 —.005 18 +.003 = 17 —.005 +.000 24 +.004 —.006 —.013 | Means +.000 —.003 —.006 +.007 + fie 33 | +.001 eal 4] —.001 02 95 +.002 —.002 y93 | 30 | —.001 fans 22 +.000 4 30 +.000 Hosea (Tan enc +.005 39 000 4.011 re ae +.021 | Means +.000 —.005 | +.006 +.017 | —.001 | +.010 | —.012 +.004 +.010 In groups of One Hour. —002| 6 | +.027 +.004 6 =A +.000 . aha: —.002 +.000 —.001 —.002 +.000 +.008 +.002 +.002 —.006 +.007 +.001 —.005 +.007 —.006 —.003 +.011 —.004 +.003 —.013 —.001 +.013 _ Crmcr wom ~“I"10 OFC .. . DOCU Ree Re OOOH Pe ROO TH eI e ONO OOO +000 | a) |) anes In groups Hours. 74 +.000 5d +.000 62 +.000 59 +.001 Means +.000 COMPARISON OF CATALOGUES OF STARS. 423 RESIDUALS ARRANGED IN THE ORDER OF DECLINATION. fimitein Auwers minus H. C. 0. Safford minus H. C. 0. Newcomb minus H. C. 0. Boss minus H.C, 0, Right Ascension. No. Stars | Aa § 4 Pas) No. Stars,| da | Ad No Stars. 8. —.007 +.003 +.014 —.005 +.001 +.009 +012 +.003 +.007 : noe sat herare 1s 18... 24 Means... Means... 424 COMPARISON OF CATALOGUES OF STARS. SECONDARY CATALOGUE. Auwers minus H. C. 0. Safford minus H. C. 0. Aa Ad Aa +.000 +.00 oe 4.006 —.012 +.001 The extraordinary agreement of the reduced positions of Safford, Newcomb, and Boss, especially in declination, with the Normal System, will not escape attention. It cannot be expected that any single catalogue will exhibit the same degree of agreement, especially if, as is the case with the Harvard College Catalogue, it has been constructed from observations made subsequent to those upon which the Normal System is founded. It is probable therefore that in a majority of the cases in which the deviations from the normal system are large, the residuals represent accidental errors of observation in the present catalogue. To this class probably belong the following stars : — In Right Ascension. In Declination. OF e Persei. 55 Cassiopeiz. 4 Urse Minoris. o' Eridani. 67 Ceti. 109 Virginis. 10 Camelopardi. Groombridge 716. 5 Bootis. 7 Leonis. 9 H. Camelopardi. 6 Aquile. £ Urse Majoris, med. Groombridge 848. y Cygni. y Virginis. 12 Canum Venaticorum, seq. 8 Aquarii. Groombridge 2415. On the other hand, I shall be disappointed if future observations do not confirm the substantial accuracy of the values given for the right ascensions of the following stars, viz.; Groombridge 29, 7 Cassiopeiw, 36 Camelopardi, 1 H. Draconis, Groom- bridge 2164, @ Draconis, » Draconis, Groombridge 2377, 6 Draconis, 8 Lyre (per- haps), Groombridge 2900, and v Pegasi. The discussion of positions which are apparently erroneous will be reserved for another paper. It will, however, be in- structive to record the present state of the testimony with respect to these stars as given in the discussion of Dr. Auwers, to which are added the positions from this catalogue instead of the places taken from Vol. X. of the Annals. Both coordinates are for 1875.0. COMPARISON OF CATALOGUES OF STARS. 425 LIST OF STARS EXHIBITING A DISCORDANCE IN RIGHT ASCENSION. PULKOWA. GREENWICH. 1871. 5. 1861. 1872. Gr. 29 = B 2.6 n Cassiopeie . ¢ Persei 10.298 Fs 9.969 10.217 aw! 32.815 32.949 35.429 Bh 45.926 6. 6pit 45.873 © 45.890 5 DOC 18.363 18.448 18.379 16.488 pG0-6 16.281 16.448 o Eridani . 10 Camelop. 36 Camelop. i=) oe ws oF 1 H. Draconis 5.801 ty fevers 5.620 5.749 5.605 TeeCOnism eta touts 30.991 ReneS 31.031 31.008 30.973 § Urse Majoris . 30.680 ee 80.594 30.629 30.742 y Virginis . : t Seerees 19.626 19.634 19.591 Groom. 2164 . est ic 16.068 16.080 16.036 okaer 6 Draconis A y erative 33.082 33.074 33.065 4 Draconis . . 22 Sede cite 18.328 18.273 18.183 Groom. 2377 . De enous 55.724 5.8 55.720 55.705 Groom. 2415 . sen his 42.146 i tes Soap Praise 27.942 27.920 B Lyre . 12.747 Groom. 2900 ' Mak: 12.997 bese | 28 19°... . 8.530 Maes: 8.472 8.547 GREENWICH. LEIPsi@. 1861. 1872. 1868. 55 Cassiopeiw . .| 2 5 é So BAIS cg || WG RRID || aad CipeCetignts.t Sea net BEEN ao oI] Baas) |) tng Groom. 716. . 3 y Bolo WeePBHa IG bo |) Bers! || Se 9 H. Camelop. 24.09 | ... | 24.43 | 24.26 Groom. 848 . Rye ig IEBRATANEI Ga 5, | Bese || BRYAN) #12 Can. Ven. . . 38 288) Neste .83 | 38.05 | 37.59 Co too 4 Urs Minoris . Woes 5.48 : 6.90 5.45 LOO) Virginis’. ~.) . 7) 95) EVE ae Deel aL Gaal d:Bootiss . =. « : é Sainte 55.96 | 55.83 OpAquilzem. % Ee ree 1.50 1.28 POO aes sy i 52 USE ea 0 (03 12 | Tae By Aquarii: . . 2 DAO eve e 12.81 | 12.81 426 COMPARISON OF CATALOGUES OF STARS. COMPARISON OF THE FOUR CATALOGUES UNDER CONSIDERATION BY MEANS OF THEIR PROPER MOTIONS, Since the proper motion is a direct function of the time, it is possible to determine the exact amount by which two catalogues will differ at the expiration of a given time. If the two systems of proper motions differ systematically, these systematic errors will be introduced into the catalogues themselves. In general, the constant part of the deviation may be considered as a function of the precession constant. The explanation of the variable part in any given case is for the most part exceedingly difficult. For example: it is easy to account for the systematic deviations between Auwers and Boss, by referring them to the corresponding deviations between the system of Bradley on the one hand and the mean of the systems of Bessel, Struve, and Argelander on the other, but I have found it impossible to trace the origin of the differences between these fundamental systems. I give below the comparison of each authority with Auwers. Columns I. and II. contain the values of Aw and Ay’ for the first and the second twelve hours of right ascension respectively. The proper motions of the secondary catalogue form the basis of the comparison in the Harvard College Observations; the corresponding values were communicated by Dr. Auwers to Pro- fessor Pickering for facilitating the reductions in Vol. XII. of the Annals. In the comparison with Safford in right ascension, Ay involves the change from the con- stants of Bessel to those of Struve. I have assumed the mean value to be the constant part of the deviation. AuUWERS minus HARVARD COLLEGE. 1G Il. CE 8. 8. Ly Lf i. —.00033 —.00020 —.00049 +.0018 +.0014 +.0021 —.00032 —.00019 —.00039 +.0039 +.0045 +.0029 —.00030 —.00023 —.00038 +.0030 +.0020 +.0041 —.00018 —.00006 —.00031 A +.0014 | +.0008 | +.0015 —.00017 +.00000 —.00031 +.0012 | +.0022 |; +.0003 —.00011 +.00003 —.00023 —.0008 | +.0005 | —.0024 —.00023 —.00052 +.00000 +.0018 | —.0012 | +.0042 —.00010 +.00003 —.00026 +.0019 | _+.0030 | +.0008 +.00045 +.00052 +.00038 +.0001 | —.0002 | +.0005 Means. . . —.00014 —.00007 —.00022 | .. +.0016 | +.0014 | +.0016 COMPARISON OF CATALOGUES OF STARS. 427 AUWERS minus SAFFORD. ack in Au L Il. Const. = | —.00222 | —,00935 | —.00210 fo} ° Ls +10...+50 | +.00018 | +.00025 | —.00010 0006 |F — —.0005 +20...+30 | —.00052 | +.00005 | —.00090 4.0020 | +. +.0024 +30...+40 | +.00038 | +.00085 | +.00010 4.0074. | +4 4.0073 +40... +50 —.00082 —.00045 —.00120 —.0034 : —.0018 +50... +60 —.00072 —.00075 —.00080 | 3: +.0033 005 +.0050 +60 ...+70 +.00148 +.00015 +.00290 +.0005 000 +.0004 Means. . . —.00222 —.00235 —.00210} .. +.0015 : +:0021 —.00084 —.00108 —.00063 t +.0126 : +.0114 —.00100 —.00098 —.00102 f +.0147 012 +.0165 —.00108 —.00087 —.00116 +.0079 007 +.0080 —.00108 —.00122 —.00094 +.0138 A +.0112 —.00083 —.00104 —.00064 +.0123 : +.0137 —.00085 —.00091 —.00084 +.0096 : +.0106 —.00071 +.00012 —.00153 y +.0182 : +.0157 —.00057 —.00078 —.00040 +.0062 00 +.0124 —.00113 —.00090 —.00137 +.0043 00% +.0060 —.00101 +.00020 —.00242 —.0035 Ab —.0070 —.00849 —.00382 —.00317 ] —.0027 0008 —.0051 —.00091 —.00075 S(Noli@ |). < +.0085 008: +.0085 rae in le : Number Stars. = F0e e .—20 +.0090 +20... +.0140 Zee 4.0113 a torre +.0155 ri ae +.0137 area +.0120 +30... +.0188 aris) 3 pa ore +.0077 =O) oc +.0045 sO) pac —.00382 ari aoc —.0030 +.0091 4928 COMPARISON OF CATALOGUES OF STARS. Comparing the deviations between the different systems in a century, we have the following results : — Maximum mean Deviation Maximum systematic Deviation in a Century. in a Century. CATALOGUES. Auwers minus Harvard College Auwers minus Safford Auwers minus Boss Auwers minus Newcomb It will be seen from the foregoing comparison that if we may consider the system of Auwers as an absolute standard, three classes of errors will be introduced into any system of observations which depends upon the systems, either of Safford, Boss, or Newcomb. These are : — (a) A constant error which is a direct function of the time. (4) Systematic errors which result from those errors in the proper motion, which are functions either of the right ascension or of the declination, and whose magnitude is proportional to the distance from the assumed common epoch. (c) Errors which will be introduced through the constant », resulting from a change in the relation between the places of the equatorial, and of the polar stars in the fundamental system chosen. The effect of these errors will be sensible in the following cases : — Cuass (a) Safford in right ascension. Crass (4) Boss and Newcomb in declination. Crass (c) Newcomb (Gould) in right ascension. But there is no decisive evidence that the system of Auwers is to be preferred to the system of Newcomb in right ascension (from 6 = —30° to 6 = +60’) or to the system of Boss in Declination. We must therefore conclude that the problem of the construction of a homogene- ous system of stellar codrdinates which will satisfy all past observations and which future observations may be relied upon to verify, has not yet been completely solved. Pig Mv aOR Re HA HERES uit vagal a Smug ree ‘ hike A . on as) ch i . ie tla #e ‘i I. 4 RA AT ae Way ' Mite ki ‘ i : a Fae eo tahdtad 2 vt ti me i i ia e ray \ Sat by a nee mete ; “ Lig ve ‘4 ‘| “ Ai ERT pecdusrens i Al tay ed EN Seen irs Reaver: