1 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE. MAGNETICAL OBSERVATIONS ARCTIC SEAS. BY ELISHA KENT KANE, M.D., U.S.N. MADE DURING THE SECOND GRINNELL EXPEDITION IN SEARCH OP SIR JOHN FRANKLIN, IN 1853, 1854, AND 1855, AT VAN RENSSELAER HARBOR, AND OTHER POINTS ON THE WEST COAST OF GREENLAND. REDUCED AND DISCUSSED, BY CHARLES A. SCHOTT, ASSISTANT D. S. COAST Sl'RVEY. [ACCEPTED FOK PUBLIOATIO ic, MAT, 1868.] COLLIHg, PRINTER. PHILADELPHIA : CONTENTS. INTRODUCTORY LETTER ..... SECTION I. MAGNETIC DECLINATION, 1854 .... i SECTION II. • OBSERVATIONS OF THE MAGNETIC INCLINATION, 1853, 1854, AND 1855 . 21 SECTION III. OBSERVATIONS OF MAGNETIC INTENSITY, 1854 AND 1855. 30 INTRODUCTORY LETTER. WASHINGTON, May 17, 1858. PROFESSOR JOSEPH HENRY, LL.D., Secretary of the Smithsonian Institution : DEAR SIR : The records of the magnetic observations made under the direction of Dr. Kane, in the second expedition to the Arctic regions, were placed in my hands by his late lamented father, Judge Kane, in December last. Dr. Kane had selected Assistant Charles A. Schott, of the Coast Survey, for the reduction of a considerable portion of the observations made in that expedi- tion; and I, therefore, placed these in Mr. Schott's possession for reduction and discussion. The work has been faithfully performed, and I recommend it for publication in the " Smithsonian Contributions to Knowledge." It is proper to state that the instruments were furnished by the Coast Survey and the Smith- sonian Institution, and that the computations have been made at the expense of the latter. Very respectfully, yours, A. D. BACHE. SECTION I. MAGNETIC DECLINATION. 1854. COMMENTS AND ADJUSTMENTS. Instruments. — The observations for diurnal inequality as well as those for abso- lute declination, were made with a Jones unifilar magnetometer (No. 3), kindly loaned by Prof. A. D. Bache, Superintendent TJ. S. Coast Survey. The azimuth circle reads to 20" and the centre division of the scale reads 280. The magnet was suspended by means of a silk thread 9i inches in length. Several trials to determine the effect of torsion gave such small quantities that it was not considered necessary to take the same into account. The instrument was not originally intended to give absolute declinations, but at the Winter Quarters the observer succeeded in obtaining a few values for absolute declination by detaching the box, containing the magnet, from the circle which bears the telescope. The same was then moved in azimuth until a well defined object within the small range of its vertical motion could be observed. The focus of the telescope was adjusted to the distance. We find the instrument " perched on a pedestal of frozen gravel," the contents of two barrels. This mounting was considered as stable as the rock underneath. On the 9th of June, 1854, Mr. Sonntag examined the instrument in reference to local disturbance, and found no sensible deviation arising from such a source. " The local deviation seems to have corrected itself; the iron in our com- fortless little cell seems to have been so distributed that our results were not affected by it." (Narrative, vol. I.) The adjustments were made according to Rid- del's magnetical instructions. The mirror attached to the suspended magnet faces the magnetic north. The following are the determinations for the angular value of a scale division: — Circle. Scale. Circle. Scale. Readings; January 13, 1854. Winter Quarters, Van Reusselaer Harbor. 120° 60'- 58' 120 16—14 120 16—14 45d.5 100.7 92.5 118° ll'-07' 117 34—30 117 34—30 253d.O 303.0 303.2 Taking alternate means, we obtain from each set the 119 30—27 119 30—27 153.5 148.0 116 49—46 116 49—46 351.0 354.5 -ld=0'.797. 118 48—45 199.0 116 13—10 394.0 118 48—45 201.0 116 05—00 405.5 118 11—07 250.5 115 31—29 451.0 - MAGNETIC DECLINATION. Circle. Scale. Circle. Ml* Readings; January 16, 1854. (Dr. Hayes, observer.) 119° 31'-31' 120 48—46 120 48—46 122 09—06 452d 350 353 251 121° 53'-55' 123 19—18 123 19—18 124 42—40 256d 150 149 42 lld=0'.741. Readings; February 16, 1854. 127° 04'- 04' 125 55—56 125 55—56 124 18—17 124 18—17 123 00—00 123 00—00 121 34—34 62 d. 5 153.0 136.0 257.0 259.7 355.0 354.5 463.0 121° 34'-34' 122 55—56 122 55—56 124 23—24 124 23—24 125 47—47 125 47—47 127 05—05 453d.O 356.0 360.0 249.0 254.0 150.0 145.5 42.0 •ld=0'.839. Value resulting, equal mean of all or one division of scale = 0'.804. Value adopted = O'.SO. An -< jncl [• of scale readings indicates a movement of the north end of the magnet to the -] I . A well rated pocket chronometer, nearly showing Greenwich mean time, was used for noting the time. Diurnal Variation. — The observations for changes of magnetic declination were made during the months of January, February, and March, 1854, at the following dates: — January 10-11 ' . " ' 13-14 . 24-25 . " 27-28 . " 31-32 . February 3-4 " 7-8 and February 10-11 14-15 17-18 21-22 28-29 March 3-4 7-8 To these must be added the term days during the same period of the year, viz: January 18—19, February 24—25, and March 22—23. The remaining three terms in April, May, and June, of the same year, furnish values of the change of the diurnal inequality at a later season. Headings (the mean of two extremes during a vibration when the magnet was in motion) were taken every sixth minute, com- mencing, with but one exception, between 4 and 5 o'clock in the afternoon. The error of the chronometer has been applied and the time in the abstracts is given in local mean (astronomical) time. The readings are, as stated above, uncorrected for torsion, and are expressed in scale divisions. In regard to the observers, Dr. Kane remarks in his narrative: " It was not until the close of the winter that I was able to take my share in the preceding (the observations for variation) or the term-day observations; and I desire to express my obligations to Dr. Hayes and MAGNETIC DECLINATION. 5 Mr. Bonsai, as well as to George Stephenson, for their zealous and intelligent co- operation with Mr. Sonntag and myself." Each set of observations extends over twenty-four hours; they were taken nearly one minute earlier (between 56* and 40s) than indicated in the abstract. The general remark on page 435 of the second volume of the Narrative, " the scale reading 280 corresponds to a magnetic declina- tion of 108° 3' west, etc.," appears to leave no doubt that the instrument was left undisturbed, and there being no statement to the contrary, we can assume the hourly and daily means at the several days of observation to refer to the same zero or to be comparable amongst themselves. At a later period in June, 1854, the azimuth circle appears to have turned about 19 minutes. Term-day Observations. — There were six in number. The observations com- mence at 10 P. M., mean Gottingen time, or about 4h 37m 34s mean Fern Rock time, the difference of longitude being assumed to equal 5h 22m 26s. The obser- vations were not taken at the precise instant as indicated in the abstracts ; the small deviation is noted at the head of each table. Absolute Declination. — The expedition not being provided with a proper instru- ment, the magnetometer was temporarily converted into a declinometer by Mr. Sonntag, who determined the declination on June 9th, the 14th, and the 26th, 1854. The top of a mountain was used as a mark; it bore south 22° west (magnetic). The mirror attached to the magnets can be inverted so that the mean reading of mirror direct and mirror reversed corresponds to the reading of the magnetic axis of the magnet. Geographical Position of Observatory. — The latitude and longitude of the astro- nomical observatory has been determined as follows: Lat. 78° 37'.0 north, Long. 70° 40' west of Greenwich. (See p. 305, vol. II. of the Narrative, also pp. 385 and 387 of the same volume.) The island (Observatory Island) on which the obser- vatory (Fern Eock Observatory) was placed, was some fifty paces long by perhaps forty broad. (See p. 116, vol. I. of Narrative.) The magnetic observatory was ad- joining; it was of stone, ten feet square, with a wooden floor as well as roof, and supplied with a copper fire grate. No iron was used in its construction. The following is an extract of note 56, p. 464, of vol. I. of the Narrative: "The subjoined are given as aids to physical inquiry on the part of future travellers: Directions to sites of Rensselaer harbor. The observatory was placed upon the northernmost of the rocky group of islets that formed our harbor. It is seventy- six English feet from the highest and northernmost salient point of this island, in a direction S. 14° E., or in one with said point and the S. E. projection of the southernmost islet of the group. A natural face of gneiss rock formed the western wall of the observatory. A crevice in this rock has been filled with melted lead, in the centre of which is a copper bolt. Eight feet from this bolt, and in the direction indicated by the creviQe, stood the magnetometer. This direction is given in case of local disturbance from the nature of the surrounding rocks." The highest point of the island was about thirty feet above the mean tide level of the harbor. The observatory was known by the name of " Fern Rock Ob- servatory." 6 CHANGES OF THE MAGNETIC DECLINATION OBSERVATIONS FOR CHANGES or THE MAGNETIC DECLINATION AT VAN RENSSELAER HARBOR, 1854. Mean Mean Hourly local 36m. 42m. 48m. 54m. 00m. 06m. 12m. 18m. 24m. 30m. local mean*. time. time. Fern Rock Observatory, January 10 and 11, 1854. 4h 300d 300d 299d.3 299d 295d.5 294d 294d 294d 293d 291. ''5 5» 296''.0 5 291 290.8 290.7 300 295.2 292.8 292 290.8 289 288.4 6 292.1 6 290.2 292 290.6 288 290 287.5 284 282.5 281 280 7 286.6 t 280 279 277 276 . 277.5 278 279.5 280 280.5 281 8 278.9 8 282 283 284 284 285 285 287 286 286 285 9 284.7 9 286 287 286 288 290 289 292 290 287 286 10 288.1 10 289 292 294 295 295 297.5 298 303 304 303 11 297.0 11 300.5 300 300 299 298 298 297 298.5 303 304 12 299.8 12 304 306 307 308 310 307.5 311 311.5 310 310.2 13 308.5 13 310 309 308.5 308.2 309.3 310 309.8 306 313 314 14 309.8 14 312 310 310 309 308 306 303.3 303.5 306 308 15 307.6 15 309.5 308 305.8 306 304.5 303 301.5 306 306 305 16 305.5 16 304 302 298 298 301 301 295 290 289 289 17 296.7 17 289 286 287 288 292 287 302 299 297 299 18 292.6 18 287 285 283 283 282 268 252 241 244 246 19 267.1 19 249 255 256 254 257 270 291 295 294 298 20 271.9 20 290 277 273 271 273 250 275 270 260 251 21 269.0 21 260 266 257 249 248 247 251 253 255.3 248.6 22 253.5 22 246.3 255 260 258 256.5 254 256.5 258.5 257 256 23 255.8 23 258 262 267.5 270 272 278.5 282.3 279.0 280 273.5 0 272.3 0 272 270 263 259 253 251 250 246 254 252 1 257.0 1 252 360 265 268 269 271 273 273 274 274 2 267.9 2 274 279 275 274 278 276 275 276 276 280 3 276.3 3 291 289 294 297 300 301 302 304 304 305 4 298.7 qi o Q1 i O1 fi 31 9 311 0LX ol4 O 1U PX9 O14 Mean 284.7 Fern Rock Observatory, January 13 and 14, 1854. 300d 299d 295d 4h 4h 302d 304d 308d 311d 314d 31 7d 315d 313 316 319 5 3iid.9 5 317 314 311 313 315 319 322 328 335 337 6 321.1 6 339 340 336 331 326 330 328 316 329 335 7 331.0 7 340 338 344 346 348 343 342 342 345 349 8 343.7 8 350 364 371 371 368 366 358 356 350 349 9 360.3 9 344 338 334 329.5 329 327 330 336 342 342 10 335.1 10 339 339.5 335.5 340 347.5 350 349 348.7 350.2 354.8 11 345.4 11 354 352 350.8 353 351 347 343 343 344.8 342.8 12 348.1 12 341 342 343.8 344 343.5 343 342 340.5 340 341 13 342.1 13 341 342 343 347 346 346 347 357 352 348 14 346.9 14 355 352 354 356 352 348 345 344 346 349 15 350.1 15 350 351 352 358 362 371 377 378 374 372 16 364.5 16 370 368 371 374 374 374 371 365 359 358 17 368.4 17 352 352 346 341 339 330 328 325 324 320 18 335.7 18 321 323 330 335 345 347 337 330 293 295 19 325.6 19 295 292.5 288 280 260 263.5 269.5 274 269.8 272 20 276.4 20 274 284 254 263 257.7 266.5 272.5 270 267 285 21 269.4 21 295 297 285 271 272.8 276 271.5 270 266 266 22 277.0 22 265 264 265.5 267 269 270 270 269 266 264 23 267.0 23 261 267 274 275 277 269 262 250 246 242 0 262.3 0 212 218 224 231 242 252 252 255 264 273 1 242.3 1 276 277 278 278 278 276.5 276 277 282 289 2 278.8 2 290 287 288 288 292 301 311 310 305.8 309 3 298.2 3 306 299 296.5 297.5 299.5 300.5 307 318 319.5 315.5 4 305.9 31 *\ 31 Q 3i A 91.9 Ola 01 o Mean 317.0 Value of a division of the scale O'.SO. Increase of scale readings corresponds to a movement of the north end of the magnet to the east. AT VAN RENSSELAER HARBOR. Mean Mean Hourly local 36m. 42m. 48m. 54m. 00m. 06m. 12m. 18m. 24m. 30m. local means. time. time. Fern Rock Observatory, January 24 and 25, 1854. 305d 305d 305d 4h 4h 30Td.J 310d 313d 315d 317d 318d 323d 326 331 333 5 319d.3 5 337 340 342 346 348 350 353 355 353.5 354 6 347.8 6 355 355 357 357 359 360 361.5 363 361 369 7 359.7 7 373 371 366 363 368 367 366 367 367 366 8 367.4 8 364 3G3 362 357 356 358 360 362 364 365 9 361.1 9 364 361 358 362 365 367 363 359 357 356.5 10 361.2 10 355 354 354.5 357 356 358 358.5 360.5 359 358.5 11 357.1 11 356.5 354 356 358.5 359 361 363 364 359 352 12 358.3 12 350 352 353.5 351.5 352 354 356 359.5 361 363 13 355.2 13 360 355 359 368 370 370 373 366 361 358 14 364.0 14 360 366 365 361 359 353 351 350.8 350 349 15 356.5 15 347 348 347 344 344 344.5 342 343 340 340 16 344.0 16 340 342 344 344 344 344 343 343 343 342 17 342.9 IT 340 338 338 337 337 338 338 339 341 342 18 338.8 18 344 345 348 348 347 346 346 346 347 347 19 346.4 19 347 348 348 349 350.5 350 349.5 348 346 336 20 a47.2 20 322 316 318 318.5 320 321 308 305 304 301 21 313.3 21 301.5 300.5 292 291 286 291.5 304 302 310 314 22 299.2 22 317 315 315 314 316 316 318 316 314 314 23 '315.5 23 315 313 312 313 314 310 309 309 308 300 0 310.3 0 298 301 304 302 292 287 282 285 288 294 1 293.3 1 300 305 300 294 292 304 304 311 309 310 2 302.9 2 312 314 316 312 308 310.5 314 315 315 314.5 3 313.1 3 316 316.5 318 316 310.5 310 310 312 315.6 318.5 4 314.3 4 311.5 310.5 Mean 337.0 Fern Rock Observatory, January 27 and 28, 1854. 4h 306d 305d 307d 313d 320d 327d 321d 315d 312d 308d 5h 313d.4 5 304 302 302 306 307 308 306 308 314 316 6 307.3 6 320 325 330 332 328 326 324 323 325 326 7" 325.9 7 326 328 323 324 324 325 325 320 319 320 8 323.4 8 319 319 319 319 318 319 320.5 321 322 322 9 319.8 9 322 322 322 322 323 324 323.7 324 323 323 10 322.9 10 322 320 322 323.7 325.8 326.5 327 327.3 325 328 11 324.7 11 329 329.8 330 329 328 326 326 337 338 334.7 12 330.7 12 332 342 342.2 341 339.5 334 331 328 330 331 13 335.1 13 331.4 336 337 334 330 336 334 332 331 330 14 333.1 14 330 332 334 330 338 347 357 353 348 344 15 341.3 15 346 348 348 346 345 345 346 351 356 350 16 348.1 1C 346 345 347 348 349 355 359 364 368 370 17 355.1 17 378 380 384 386 388 389.5 388 387 387.5 386 18 385.4 18 386 386 386 386 385 381 378 375 375 374 19 381.2 19 374 373 370.8 365 365 360 355 355.5 352 349.5 20 362.0 20 360 365 362 360 356 353 352 351.5 353 356 21 356.8 21 354.5 356 357.5 360 362 364.5 365 365.5 363 361 22 363.8 22 359 360 361 362 363 365 367 368 365 363 23 363.3 23 360 356 341 346 341.5 336 337 338 338 335 0 342.8 0 332 335 339 342 341 340 340 341 342 346 1 339.8 1 351 356 360 359 358 363 355 362 357 354 2 357.5 2 350 350 350 348 346 350 345 344 349 350 3 348.2 3 352 352 353 355 358 359 354 340 333 332 4 348.8 4 336 340 343 345 345 Mean 342.9 Value of a division of the scale O'.SO. Increase in scale readings corresponds to a movement of the north end of the magnet to the east. Aurora visible on the 27th and 28th. 8 CHANGES OF THE MAGNETIC DECLINATION Mean Moan Hourly local 36m. 42m. 48m. 54m. 00m. 06m. 12m. 18m. 24m. 30m. local means. time. time. Fern Rock Observatory, January 31 and February 1, 1854. 304d 306d 325d 41, 4" 332 d. 5 340d 341d.5 335 d.5 345d 333d.5 334d.5 330 330 328 5 335 d.O 5 326 327 328.5 324 318 311 313 320 325 330 6 322.2 6 338 344 348 356 358 359.5 356 357 358 358 7 353.2 7 359 359 360 360.5 361 362 363.5 365 367 368.5 8 362.5 8 370 372 372 374 371 370 371 371 371 372 9 371.4 9 372 372 373 373 374 372 372 372 371 370 10 372.1 10 368 368 367 364 361 365 371 370 369 367 11 367.0 11 365 366 370 377 376 377 380 387 384 382 12 376.4 12 379 374 375 376 374 373 370 368 374 375 13 373.8 13 376 .376 380 384.5 385 384 383.5 382 380 378 14 380.9 14 379 381.5 383 384 385.5 383 380 379 376 370 15 380.1 15 368 365 364 365 367 369 371 373.5 374 375 16 369.1 16 374.5 375 375 374.5 374 375 374 374 373 373 17 374.2 17 373 374 374.5 375 374 374 374 375 378 382 18 375.3 18 385 387 390 389 388 388 389 390 385 386 19 387.2 19 387 388 389.8 387 389 389 389 387 387 386 20 387.9 20' 385 385 385 384.5 383 382 382 382 376 370 21 381.4 21 367 369 370 370 292 288 278 284 285 291 22 319.4 22 " 294 297 311 328 338 348 359 359.5 351 350 23 333.5 23 342 338 334 318.5 314 312 311 314 318 323 0 322.4 0 329.5 331 322 332 333 342 346 350 359 365 1 340.9 1 370 370 370 375 381 379 •375 372 368 364 2 372.4 2 359 356 355 354 352 351 351 350 363 373 3 356.4 3 375 377 377 380 383 376 376 378 380 386 4 378.8 A ann QQft 400 398 396 419 430 440 5 t O ' 4h 190d 1841' 172d 172d 169d 172d 181d 188 196 198 5 182d.2 5 193 183 185 188 180 182 185 195 207 208 6 190.6 6 208 230 258 298 296 286 272 271 270 270 7 265. 9 7 265 258 252 244 237 230 227 225 226 228 8 239.2 8 232 235 238 242 249 255 260 260 261 262 9 249.4 9 262 263 265 268 273 276 279 281 291 300 10 275.8 10 302 300 280 273 260 249 242 236 228.5 237 11 2G0.7 11 241 247.5 245 240 236 231 232 230 229 227.8 12 235.9 12 225 222 240 238 242 239 236 230 247 253 13 237.2 13 261 248 240 231 233 237 250 244 242 240 14 242.6 14 238 236 235 238 243 242 240.5 237 234 231 15 237.4 15 229 229.5 234 239.5 239 238 240 241 243 247 16 238.0 16 249 251 250 247 245 242 237 233 228 223 17 240.5 • 17 218 220 223 228 232 235 237 238 239 240 18 881.0 18 235 232 230 233 235 237 233 228 -234 237 19 233.4 19 240 234 228 220 204 166 164 147 130 152 20 188.5 (20 179 188 206 230 256 250 241 236 226 217 21 222.9 21 218 221 224 221 217 208 221 237 244 245 22 225.6 22 244 248 254 250 247 244 242 241 240.5 240 aa 245.0 23 240 250 252 247.5 238 227 220 219 216 214 0 232.3 0 214 215 216 220 226 232 236 240 247 255 i 230.1 1 262 271 180* 190 187 184 181 177 175 174 2 198.1 2 169 163 156 150 144 146 148 147 152.5 151 3 152.6 3 154 151 161 175 • 187 192 201 202 202 208 4 183.3 A -> 1 ii 904 99R 9'^Q ft £i i \J •w 9«w Bvw Mean 226.6 Value of a scale division 0'.80. Increase of scale readings corresponds to a movement of the north end of the magnet to the east. NOTE. — The mean in brackets includes two interpolated values. * A sudden change of 90d occurring at Gh 30™ chronometer time (Greenwich time nearly). AT VAN RENSSELAER HARBOR. 11 Mean Mean Hourly local 36m. 42m. 48m. 54m. 00m. 06m. 12m. 18m. 24m. 30m. local means. time. time. Fern Rock Observatory, February 21 and 22, 1854. 270d 269d 268d 4h 4h 268d 268d 273d 276d 271d 260d 252d 252 252 252 5 262d.4 5 252 253 256 256 .253 254 256 257 258 260 6 255.5 6 261 263 263 265 267 267 268 269 271 273 7 266.7 7 274 275 276 277 280 282 286 291 296 301 8 283.8 8 302 302 303 303 302 302 301 302 301 299 9 301.7 9 296 293 290 289 287 286 284 283 283 283.5 10 287.4 10 282.5 280.5 278.5 276 274 274 274 279 284 287 11 278.9 11 288 289 290 294 • 297 299 300 296 294 293 12 294.0 12 292 292 290 287 284 281 276 276 275 280 13 283.3 13 285 287 290 293 297 290 282 280 278 276 14 288.3 14 276 278 282 282 284 285 287 287 287 288 15 283.6 15 288 288 289 290 293 293' 294 294 296 296 16 292.1 16 295 295 293 292 291 291 293 290 287 283 17 291.0 17 280 278 275 272 271 268 267 266 265 263 18 270.5 18 261 260 258 255 254 255 257 260 262 263 19 258.5 19 264 262 259 260 261 261 260.5 260 259 256 20 260.2 20 251 244 240 242 230 218 216 212 205 203 21 226.1 21 206 210 216 221 223 224 230 237 250 250 22 226.7 22 250 250 254 257 258 262 260 260 261 263 23 257.5 23 261 260 260 258 260 261 262 262 262 262 0 260.8 0 262 262 262 262 263 263 262 261 261 260 1 261.8 1 259 259 258 257 258 259 259 260 261 263 2 259.3 2 2'64 266 269 271 273 275 277 280 278 274 3 272.7 3 274 275 278 290 294 304 293 286 282 280 4 285.6 4. 283 282 279 276 jt m 9 9 Mean 271.2 Fern Rock Observatory, February 28 and March 1, 1854. 220d 220d 21 9d 4h 4h 21 8d 216d 213d 207d 200d 191d 183d 179 180 182 5 196d.9 5 184 186 189 191 192 193 193 192 193 193 6 190.6 6 195 198 202 210 219 227 230 244 256 260 7 224.1 7 272 274 280 278 242 226 220 250 300 320 8 266.2 8 344 333 321 310 306 322 335 341 350 362 9 332.4 9 353 352 350 355 368 365 360 370 371 372 10 361.6 10 374 378 399 402 408 404 398 394 390 400 11 394.7 11 398 396 397 402 405 408 407 421 436 440 12 411.0 12 452 476 484 483 450 438 418 400 390 381 13 437.2 13 372 363 354 343 337 343 347 352 357 364 14 353.2 14 372 355 340 324 315 320 326 330 333 335 15 335.0 15 331 327 325 324 322 325 314 320 315 314 16 321.7 16 326 338 346 363 362 356 348 342 342 339 17 346.2 17 325 322 324 318 316 324 312 310 318 322 18 319.1 18 319 318 317 314 312 316 317 314 314 317 19 315.8 19 320 315 314 310 308 309 308 307 308 308 20 310.7 20 306 306 302 298 297 299 302 302 301 301 21 301.4 21 298 299 300 301 296 284 274 269 264 268 22 285.3 22 272 278 280 283 286 288 284 279 276 280 23 280.6 23 285 303 320 332 341 350 362 374 366 356 0 338.9 0 345 333 321 310 296 293 305 296 289 280 1 306.8 1 274 276 266 264 258 256 252 259 251 255 2 261.1 2 278 260 261 262 265 268 276 280 286 291 3 2727 3 299 301 299 302 306 310 314 316 317 320 4 308.4 4 319 317 318 315 312 5 «J -L | Mean 311.3 Value of a scale division O'.SO. Increase of scale readings corresponds to a movement of the north end of the magnet to the east. 12 CHANGES OF THE MAGNETIC DECLINATION Mean Mean Hourly local 36m. 42m. 48m. 54m. 00m. 06m. 12m. 18m. 2-liu. 30m. local means. time. time. Fern Rock Observatory, March 3 and 4, 1854. 250d 247d 24 6d 4h 41, 248d 249d 240d 238d 242d 245d 248d 250 260 265 5 248d.5 5 258 269 281 284 380 279 277 . 274 275 277 6 275.4 6 280.5 279 272.5 275 270 280 286 290 298 296 7 282.7 7 283 311 315 332 329 326 321 329 347 349 8 324.2 8 356 356 360 352 347 346 330 302 291 283 9 332.3 9 287 290 282 286 275 264 265 267 269 '270 10 275.5 10 272 274 276 278 280 282 285 287 290 292 11. 281.6 11 295 298 302 306 313 318 322 325 327 329 12 313.6 12 330 337 345 349 352 350 348 345 343 336 13 343.5 13 325 321 313 302 295 299 308 314 309 302 14 308.8 14 297 294 288 292 286 284 280 276 272 285 15 285.4 15 291 294 291 289 282 276 268 264 260 258 16 277.3 16 257 257 256 258 259 260 262 260 258 258 17 258.5 17 257 255 251 244.5 238 230 220 205 190 172 18 226.2 18 152 144 133 134 136 140 143 160 174 198 19 151.4 19 209 216 210 205 201 195 190 186 181 177 20 197.0 20 173 170 167 164 171 178 184 189 193 199 21 178.8 21 206 200 194- 188 183 178 172 170 169 164 22 182.4 22 152 160 156 156 153 155 157 154 150 150 23 154.3 23 156 176 195 184 155 160 125 131 131 134 .0 154.7 0 135 137.5 155 179 195 184 187 200 197.5 192 1 176.2 1 195 200 190 185 182 179 150 136 150 156 2 172.3 2 173 190 200 206 217 204 196 190 186 183 3 194.5 3 189 192 199 204 209 216 222 229 234 243 4 213.7 4 249 251 254 257 Mean 242.0 Fern Rock Observatory, March 7 and 8, 1854. 190d 202d 4u 4h 218d 223d 213d 218d 2281 224d 221d 231d 230 235 5 224d.l 5 242 243 246 247 251 270 275 275 274 274 6 259.7 6 269 261 268 260 273 270 269 255 268 271 7 266.4 7 275 271 279 284 278 269 281 282 281 286 8 278.6 8 292 304 • 294 302 303 312 306 299 297 293 9 300.2 9 284 288 286 287 291 294 300 305 298 290 10 292.3 10 287 280 276 270 277 280 286 281 278 273 11 278.8 11 269 272 267 270 272 274 267 268 272 280 12 271.1 12 273 279 284 290 289 291 294 291 283 274 13 284.8 13 290 288 285 282 283 291 297 300 296 291 14 290.3 14 285 278 281 284 298 291 289 286 284 283 15 285.9 15 281 282 285 288 290 292 295 297 298 298 16 290.6 16 299 300 302 297 291 285 280 278 283 288 17 290.3 17 292 296 299 297 295 293 289 287 281 275 18 290.4 18 269 264 260 256 260 255 258 260 266 270 19 261.8 19 275 272 277 264 270 268 270 259 271 268 20 269.4 20 264 276 278 270 264 260 268 282 284 286 21 273.2 21 280 278 281 285 287 274 291 297 295 291 22 285.9 22 284 276 274 268 263 257 264 271 286 293 23 273.6 23 300 299 287 285 281 274 278 271 267 265 0 280.7 0 261 246 252 245 247 243 242 246 250 252 1 248.4 1 252 252 250 250 249 250 252 255 256 258 2 252.4 2 260 265 270 272 275 276 276 280 285 280 3' 273.9 3 285 284 274 258 242 247 258 263 4 (264.3) 4 262 265 268 258 245 5 Mean 274.5 Value of a scale division O'.SO. Increase of scale readings corresponds to a movement of the north end of the magnet to the east. NOTE. — The mean in brackets includes two intorpolntod values. AT VAN 11ENSSELAER HARBOR. 13 Diurnal Range of the Declination. — The diurnal range being an index to the magnitude of the diurnal excursions, is best presented before the examination of the diurnal inequality. The following table contains the highest and lowest scale readings in the hourly series, and the maximum and minimum values observed, together with the corresponding ranges. One division of scale = 0'.80. DAILY RANGE OF THE DECLINATION. DATE. IN HOURLY SERIES. OBSERVED. RANGE. 1854. Highest. Lowest. Maximum. Minimum. In hourly series. Total observed. January 10-11 309d.8 • 253d. 5 314d.O 241d.O 56d.3 73d. 0 13-14 368.4 242.3 378.0 212.0 126.1 166.0 18-19 357.9 109.7 369.0 85.0 248.2 284.0 24-25 367.4 293.3 373.0 282.0 74.1 91.0 27-28 385.4 307.3 389.5 302.0 78.1 87.5 31-32 387.9 319.4 440.0 278.0 68.5 162.0 February 3- 4 433.1 268.6 457.0 258.0 164.5 199.0 7- 8 391.2 279.7 396.0 266.5 111.5 119.5 10-11 464.8 202.7 504.0 195.0 262.1 309.0 14-15 490.3 165.8 494.0 129.0 324.5 365.0 17-18 275.8 152.6 302.0 130.0 123.2 172.0 21-22 301.7 226.1 304.0 203.0 75.6 101.0 . 24-25 531.3 321.4 558.5 268.0 209.9 290.5 Maich 0- 1 437.2 190.6 484.0 179.0 246.6 305.0 3- 4 343.5 151.4 360.0 125.0 192.1 235.0 7- 8 300.2 224.1 312.0 190.0 76.1 122.0 22-23 290.5 238.8 304.0 228.0 51.7 76.0 The mean diurnal total range observed during the above period becomes 2° 28'.6, and the maximum diurnal range observed took place on the 14-15 February, and amounted to 4° 52'. 0. For comparison with similar quantities at other high lati- tude stations we may take Lake Athabasca, where the greatest range in any one day between October, 1843, and February, 1844, was 2° 35', it happened October 16, 1843; at Fort Simpson the maximum range was 7° 27', observed on the 16th of April, 1844, in a series of observations extending over April and May, 1844. The mean diurnal range during January and February, 1844, at Lake Athabasca, was 31'. 4, and the mean range at Fort Simpson in April and May of that year was 1° 12', these two quantities, however, were taken from the hourly series. If we classify the ranges according to this magnitude we obtain the following results : — Daily range less than " " between 1° 1 and 2° 2 and 3 3 and 4 4 and 5 " greater than 5 1 6 4 3 3 0 The diurnal range in the winter months, January, February, and March, when compared with its annual fluctuation, is probably below the mean value of the year. 14 CHANGES OF THE MAGNETIC DECLINATION Diurnal Inequality of the Declination. — The following table contains the hourly means of all observations at the Winter quarters, between January 10 and March 23, 1854. The remaining observations on term-days at a later season have been excluded on account of their isolation. The above period includes the coldest season of the year, and during more than one-half of the period the sun was below the horizon. * The hourly means were made out separately for each month, the general mean includes seventeen values for each of the twenty-four hours. In January we have complete observations on six days, in February on seven, and in March on four days. The table also contains the monthly means, and all numbers are expressed in scale divisions (one division = 0'. 80). AT YAN RENSSELAER HARBOR. 15 ABSTRACT OF HOURLY MEANS DURING THE MONTHS OF JANUARY, FEBRUARY, AND- MARCH, 1854, OBSERVED AT FERN ROCK MAGNETIC OBSERVATORY. (The readings are given in scale divisions ; the values taken from the term-day observations embrace the same number of single readings between the same times.) Fern Rock mean time. 5h. 6h. 7h. 8h. 9h. lOh. lib. 12h. 13h. 14h. 15h. 16h. 17h. Fern Rock Observatory, January and March, 1854. Jan'y 10-11 " 13-14 " 18-19 " 24-25 " 27-28 " 31-32 296.0 311.9 308.2 319.3 313.4 335.0 292.1 321.1 316.9 347.8 307.3 322.2 286.6 331.0 317.3 359.7 325.9 353.2 278.9 :M:;.T 313.3 367.4 323.4 362.5 284.7 288.1 360.3 335.1 319.9 321.8 361.1 361.2 319.8 322.9 371.4 372.1 297.0 345.4 343.3 357.1 324.7 367.0 299.8 348.1 346.7 358.3 330.7 376.4 308.5 342.1 338.4 355.2 335.1 373.8 309.8 346.9 345.3 364.0 333.1 380.9 307.6 350.1 347.8 356.5 341.3 380.1 305.5296.7 364.5368.4 353.8357.9 344.0342.9 348.1355.1 369.1374.2 Means 313.9 317.9 329.0 331.5 336.2 333.6 339.1 343.3 342.2 346.7 347.2 347.5'349.2 Feb'y 3- 4 7- 8 " 10-11 " 14-15 " 17-18 " 21-22 " 24-25 *356.7 315.7 293.6 (307.0) 182.2 262.4 344.7 *362.1 322.5 354.1 349.4 190.6 255.5 429.6 *377.0 341.9 362.9 380.4 265.9 266.7 461.2 *(373.5) 351.4 381.8 421.1 239.2 283.8 514.1 366.0 368.6 355.3 355.0 391.4 383.5 419.7 473.7 249.4 275.8 301.7 287.4 531.3 526.4 375.5 370.4 377.3 444.1 260.7 278.9 491.8 397.6 370.8 383.9 477.4 235.9 294.0 498.3 407.1 372.8 390.9 413.0 237.2 283.3 498.2 433.1 391.2 405.3 456.2 242.6 288.3 496.2 409.5 378.6 464.8 459.4 237.4 283.6 501.2 396.0399.8 345.4336.2 464.7J388.5 490.3448.4 238.0!240.5 292.1291.0- 512.4520.8 Means 294.6 323.4 350.9 366.4 373.5 381.5 371.3 379.7 371.8 387.6 390.7 391.3375.0 March 0- 1 " 3-4 " 7- 8 " 22-23 196.9 248,5 224.1 261.3 190.6 275.4 259.7 246.3 224.1 282.7 266.4 258.5 266.2 324.2 278.6 258.6 332.4 361.6 332.3 275.5 300.2 292.3 240.9 238.8 394.7 281.6 278.8 270.1 411.0 313.6 271.1 280.3 437.2 343.5 284.8 274.3 353.2 308.8 290.3 266.7 335.0 285.4 285.9 260.8 321.7!346.2 277.3258.5 290.6290.3 269.6269.8 Means 232.7 243.0 257.9 281.9 301.{ > 292.1 306.3 319.0 334.9 304.8 291.8 289.8 291.2 General means 286.9 302.5 321.3 334.2 343.3 343.5 344.6 352.6 352.7 353.5 352.0 352.1346.2 .1 Fern Rock mean time. 18h. 19h. 20h. 21h. 22h. 23h. Noon. Oh. lh. 2h. 3h. 4h. Daily means. Jan'y 10-11 " 13-14 " 18-19 " 24-25 ' " 27-28 " 31-32 292.6 335.7 347.7 338.8 385.4 375.3 267.1 325.6 327.9 346.4 381.2 387.2 271.9 276.4 348.1 347.2 362.0 387.9 269.0 269.4 336.3 313.3 356.8 381.4 253.5 277.0 306.4 299.2 363.8 319.4 255.8 267.0 236.2 315.5 363.3 333.5 272.3 262.3 •109.7 310.3 342.8 322.4 257.0 242.3 246.6 293.3 339.8 340.9 267.9 278.8 289.3 302.9 357.5 372.4 276.3 298.2 333.1 313.1 348.2 356.4 298.7 305.9 321.3 314.3 348.8 378.8 284.7 317.0 313.9 337.0 342.9 362.2 Means 345.9 239.2 883.8 321.0 303.2 295.2 270.0 286.7 311.5 320.9 328.0 326.8 Feb'y 3- 4 " 7- 8 " 10-11 " 14-15 " 17-18 " 21-22 " 24-25 376.2 311.7 361.9 406.7 231.0 270.5 492.4 361.8 288.6 314.8 376.2 233.4 258.5 494.0 302.8 279.7 264.0 333.1 188.5 260.2 448.1 268.6 303.9 271.1 343.1 222.9 226.1 433.8 309.2 301.6 242.2 289.0 225.6 226.7 321.4 346.3 302.9 202.7 243.7 245.0 257.5 401.2 329.4 319.9 208.3 165.8 232.3 260.8 (389.9] 339.6 310.7 205.3 183.6 230.1 261.8 378.7 337.5 332.9 281.1 247.0 198.1 259.3 377.7 309.8 306.7 336.2 247.0 152.6 272.7 407.7 304.0 321.5 362.0 300.9 183.3 285.6 443.7 358.6 332.8 337.2 360.7 226.6 271.2 454.8 Means 350.1 332.5 296.6 295.6 273.7 285.6 272.3 272.8 290.5 290.4 314.4 334.6 March 0- 1 " 3- 4 " 7- 8 " 22-23 319.1 226.2 290.4 255.0 315.8 151.4 261.8 286.0 310.7 197.0 269.4 (285.0) 301.4 178.8 273.2 (275.8) 285.3 182.4 285.9 254.7 280.6 154.3 273.6 287.0 338.9 154.7 380.7 290.1 306.8 176.2 248.4 287.0 261.1 172.3 252.4 247.3 272.7 194.5 273.9 244.8 308.4 213.7 (264.3) 290.5 311.3 242.0 274.5 266.6 Means 272.7 253.8 265.5 257.3 252.1 248.9 266.1 254.6 233.3 246.5 269.2 273.6 General means 330.4 316.3 302.0 295.5 279.0 280.3 270.0 273.5 284.4 290.8 308.6 317.3 The values in the above table do not refer exactly to the even hour but to 3m later. Figures between brackets ( ) are means derived from less that ten readings. * These four values were observed on the 4th at the hours indicated. 16 CHANGES OF THE MAGNETIC DECLINATION MEAN MONTHLY CURVES or THE DIURNAL CHANGES OF THE MAGNETIC DECLINATION AT VAN RENSSELAER HARBOR, 1854. AND SIMULTANEOUS MEAN DIURNAL VARIATION AT GREENWICH. 4A 5 6 7 8 9 10 llMiatv. 13 14 15 16 17 IB 19 20 21 22 23 Noon 1 2 3 4A 9 10 HMidn.13 14 15 16 17 18 19 20 21 22 23 Noon 123 The irregularities in the daily curves compared on succeeding days are very considerable, as may be seen by glancing the eye over the last column of the pre- ceding table, headed "daily means." No observations on account of disturbances have been excluded from the table, and the following mean diurnal inequality, therefore, contains their full eifect. Comparing each hourly mean in the last horizontal line of the above table with the general mean, the following figures represent the resulting diurnal inequality of the declination during the first three months of the year 1854. For the sake of comparison the diurnal inequality observed at Greenwich during the same seventeen days has been made out and is given in the last column. AT VAN RENSSELAER HARBOR. 17 MEAN DIURNAL INEQUALITY OP DECLINATION DURING SEVENTEEN DAYS IN JANUARY, FFBRUARY, AND MARCH, 1854, AT VAN RENSSELAER HARBOR, AND AT GREENWICH DURING THE SAME DAYS; EXPRESSED IN MlNUTES OF ARC. Local Van Green- Local Van Green- Local Van Green- Local Van Green- mean Rensselaer. wich. mean Rensselaer. wich. mean Rensselaer. wich. ; mean Rensselaer. wich. time. time. time. time. 5* + 24'.3 —0/5 IV — 21'.8 _4'.S 17h — 23'. 1 — 0'.3 23h + 29'.6 + 3'.5 6 + 11.8 —2.5 Midn. —28.2 —4.1 18 —10.5 + 0.6; Noon + 31.8 + 5.8 1 — 3.2 —1.6 13 —28.3 —3.1 19 + 0.8 —0.4 1 +35.0 + 5.8 8 —13.5 —3.9 14 —29.0 —0.8 20 + 12.2 + 0.5 j 2 + 26.3 + 5.0 9 —20.8 —4.5 15 —27.8 —0.3 21 + 11.4 + 1.0 j 3 + 21.2 + 3.9 10 —21.0 —5.1 16 —21.8 + 0.5 22 + 30.6 +2.3 4 + 1.0 + 2.6 A negative sign indicates a deflection to the east, a positive one a deflection to the west of the mean position. The diurnal inequality at the two stations presents in general the same charac- teristic features, namely, the principal deflection to the west shortly after noon, and the opposite eastern position about midnight ; in regard to the diurnal ine- quality, therefore, the motion of the magnet at Van Rensselaer Harbor follows in general the same law as recognized in lower geographical latitudes. The extreme westerly position is attained at noon ; after this hour the westerly declination diminishes gradually, with an exception of a period of opposite motion of very limited range between the hours of four and five. The easterly extreme is reached two hours after midnight. Whether the small irregularity just noticed, producing apparently a secondary minimum and maximum, is real or only caused by the accidental deviations of the few observations under discussion, it is not easy ' to decide with certainty. The motion from 14 hours to 24 hours is performed with great uniformity. Thus, while the diurnal motion agrees with that observed at Lake Athabasca, Fort Simpson, Sitka, Toronto, etc., it shows no trace of that marked deviation observed at Reikiavik, in Iceland, or at Fort Confidence. In 1824 (June), at the Whalefish islands the maximum westerly deviation happened about a quarter past one o'clock P. M. ; the time of the maximum eastern deflection was not determined. At Port Bowen the maximum westerly variation appears to have occurred between the hours of 10 A. M. and 1 P. M., the mean result being II1' 49"; the greatest deflection of the north end of the needle to the eastward took place between 8 P. M. and 2 A. M., the mean hour being 10 P. M. These observations were made during January, February, March, and April, 1825. The range of the mean diurnal inequality is 1° 06'. 8, when it is at Greenwich during the same time 10'.9. Analysis of Disturbances of the Declination. — The declination at the commence- ment and end of the observations appears to have remained nearly the same ; the daily and monthly means indicate at first a gradual decrease of westerly declination, which motion, however, is speedily overcome in the month of March. No further attention need be paid to this circumstance in the following discussion of the dis- turbances, and of their effect upon the diurnal inequality. The mean disturbance for each of the 24 hours has been obtained by comparing the monthly mean with each hourly reading; let A equal this difference, n the 3 18 CHANGES OP THE MAGNETIC DECLINATION number of hourly readings (equal to 17), and m the mean disturbance, then m = I t V A 2 This quantity is analogous to the mean error of an observation. In ^ t the following comparisons we must always bear in mind that the observations for the present discussion are rather limited, and that the comparisons with results at Lake Athabasca and Fort Simpson are of a date nearly ten years earlier. This interval is perhaps favorable to the comparison. At Van Rensselaer Harbor the mean disturbance force is greater than at either place just named, and pretty regular during two well-marked periods, as shown by the following table : — TABLE OF THE MEAN DISTURBANCE OF THE DECLINATION AT VAN RENSSELAER HARBOR, TAKEN WITHOUT REGARD TO DIRECTION, FOR EACH OF THE OBSERVATION HOURS, AND EXPRESSED IN MlNUTES OF ARC. Local Mean Time. 5h. 6h. 7h. 8h. 9h. lOh. llh. Micln. 13h. Mh. 15h. 16h. ±31' 41 37 47 49 50 46 5-2 51 47 50 ±53' ITh. 18h. 19h. 20h. 21h. 22h. 23h. Noon. lh. 2h. 3h. 4h. ±49' 42 54 48 46 31 46 601 46 39 45 ±41' • •."I The disturbing force is least during the day (if such an expression is admissible in this case), from 10 A. M. to 7 P. M., and greater and equally regular during the hours of the night (?), from 8 P. M. to 8 or 9 A. M. At Lake Athabasca the hours ^\ /• of least disturbance are between 9 A. M. and 7 P. M., and at Fort Simpson from 10 A. M. to 7 P. M. Captain Lefroy, in his discussion of the disturbances of the declination remarks : " There are indications in each of the three curves (for Lake Athabasca, Toronto and Sitka) of a small increase in the mean disturbance about noon." At Van Rensselaer Harbor we find the maximum disturbance at this very hour preceded and followed by quite small values; this circumstance certainly deserves our particular attention. Further coincidences of the disturbing force can be noticed at 5 P. M., at which hour at Van Rensselaer, Lake Athabasca, and Sitka the minimum disturbance has been observed. At Fort Simpson, in April and May, 1844, the mean disturbance was but one-fourth of that observed in January, Feb- ruary and March at Van Rensselaer, and the ratio of the minimum to the maximum value was 5.6 and 2.0 at the two places respectively. By adding the squares of the differences for each hour of the day and month, we find the mean monthly disturbance by the formula f-t _J. The \N — 24 ance for each month is as follows : — mean disturb- In January, 1854 In February, " In March, " ±30' ±65 ±40 1 Principally clue to a very large disturbance. AT VAN RENSSELAER HARBOR. 19 The month of February was, therefore, that of the maximum amount of disturb- ance. At Lake Athabasca the greatest mean disturbance occurred in January (from observations between October and February inclusive). At Toronto,1 on the contrary, the months of January and June are those of least disturbance. It is quite possible that at Van Rensselaer the above values are surpassed in other months of the year, yet relatively February contains the greatest mean disturbance during the period of observations. Hitherto the recognition and separation of the disturbed observations have been effected by an arbitrary process of fixing upon a certain deviation from the mean as the greatest allowable departure, and regarding all observations beyond this limit as disturbances. In the present case, I have sought to introduce a more definite idea by the application of Pierce's criterion for the rejection of doubtful observations,2 or what is equivalent — for the recognition of the disturbances — they following a different law from the general one. The average mean deviation of the readings composing an hourly mean I find = _+ 46', and for 17 values of = 4.55; hence readings deviating from the mean more than 1° 38' or 123d are to be recog- nized as disturbances. The table of hourly readings contains 23 such values, or one disturbed observa- tion for every 18 ordinary readings. In the five years of hourly observations ending June 30, 1848, at Toronto, the disturbances averaged one in 17 of the whole body. Excluding the above 23 values from the mean, the diurnal inequality freed of the disturbances undergoes no material change, as shown by the following table : — 5h. 6h. 7h. 8h. 9h. 10h. llh. Midn. 13h. 14h. 15h. 16h. + 23'. 7 + 6.0 —3.8 —9.3 —16.4 —12.5 —22.5 —34.7 —27.3 —35.1 —34.1 — 26'. 0 17h. 18h. 19h. 20h. 21h. V 22h. 23h. Noon. lh. 2h. 3h. 4h. — 20'. 1 —8.0 + 9.0 + 19.0 + 23.3 + 30.0 + 29.0 + 29.2 + 34.4 + 25.7 + 13.6 + 6'. 9 The maximum west deflection is displaced from noon to one o'clock. The general mean changed from 317.3d to 316. 5d, and the range of the mean inequality from 1° 06'.8 to 1° 09'.5. Eleven deflections were towards the east and twelve towards the west. The limited number of observations renders it necessary to conclude the foregoing examination of the disturbances. Aurora Borealis. — In connection with the disturbances, a short notice of the auroral displays witnessed at the winter quarters will here find an appropriate place. In conformity with the supposed periodicity of this phenomenon, as recognized by Prof. Olmstead, no brilliant and complete auroras have been seen ; with an excep- tion of a very few, they may all be placed in his fourth class, to which the most simple forms of appearances have been referred. The aurora of October 24, 1854, 1 See Vol. III. of the Magnetical and Meteorological Observations at Toronto, Canada. Discussion by Major-General E. Sabine. London, 1857. 3 See Gould's Astronomical Journal, Nos. 45 and 83. 20 CHANGES OF THE MAGNETIC DECLINATION at 9 P. M. (see first volume of the Narrative), appears to have heen one of the more conspicuous displays. A full record of the rest will be found in the 8th volume of the Smithsonian Contributions to Knowledge, in the collection made by Peter Force, Esq. There are 19 in number. The following statement is given in afoot-note: "The processes have no apparent connection with the magnetic dip, and in no case did the needle of our unifilar indicate disturbance." Term-day Observations for Change of Magnetic Declination. — These observations were made at the following dates: January 18-19, February 24-25, March 22-23, April 19-20, May 26-27, and June 21-22, 1854. The readings arc given in the following tables : — AT VAN RENSSELAER HARBOR. 21 TERM-DAY OBSERVATIONS FOR CHANGES OP MAGNETIC DECLINATION AT VAN RENSSELAER HARBOR, 1854. GBttingen Fern Rock mean time. Om. OCm. 12m. 18m. 24m. 30m. 36m. 42m. 48m. 54m. mean time. (toOm.) Fern Rock Observatory, January 18 and 19, 1854. Readings taken 2m 14s earlier than indicated. 10" 305d 305d 305d 307d 308d 312d 311d.8 306d.5 309d.5 312d.5 4h37m.5 11 311.2 313 314 315.8 318.5 317 317 319.7 320.5 322.5 5 " 12 320 314.8 315 315.7 317 320 321 320 316 314 6 " 13 311 307 309 311 313 315 317 318 317 315 7 " 14 320 322 319 316 320 320 322 318' 320 322 8 " 15 321 323 323.3 322.3 320 319 320 320 325 325 9 " Ifi 329 329 330 330 327 336 350 366 367 369 10 " It 362 354 353 347 347 346 346 341 337 334 11 18 330 332 335 338 338 340 342 343.5 342 344 12 " 19 344 346.5 3-45 344 344 345 346 346.5 347 345 13 " 20 346 345 345.5 345 348 347.5 349 351.5 351.5 349.5 14 " 21 349 354 359 363.5 359.5 351 350 351 350.8 351 15 " 22 356 358 359 361.5 361 355 352.3 357.8 358 360.5 16 " 23 360.5 358 355 351.5 350 349 346 340 332 335 17 " 0 336 333 330.5 326 320 320 323 226 328 337 18 " 1 343 352 350 346 340 348 353 357 349 343 19 " 2 337 332 328 324 332 336 340 343 346 345 20 " 3 342 339 329 320 313 300 292 284 277.5 268 21 " 4 251 244.5 240.5 250 261 254 243 230 235 155 22 " 5 115 90 89 96 88 85 105 129 145 155 23 6 163 180 193 220 254 290 291 307 298 270 0 " 7 268 254 240 266 289 297 320 318 320 321 1 " 8 336 336 336 331 337 337 337 330 327 324 2 " 9 314 326 332 338 323 318 316 316 316 314 3 " 10 312 310 4 " The series commences with readings 304d, 303d, and 304d, at 9h 42m, 48m, and 54m. Fern Rock Observatory, February 24 and 25, 1854. Readings taken 2m 15s earlier than indicated. 10h 312d 322d 329d 338d 341 d.5 319d.5 342d 359d 377d 407d 4h37m.5 11 408 411 405 418 437 445 445 447 441 439 5 " 12 438 438 440 432 460 482 477 471 480 494 6 " 13 490 493 506 520 516 509 519 531 530 527.5 7 " 14 541 558.5 532 527 518 511 521 532 538 535 8 " 15 532 529 527 528 530.5 542 526 521 516 513 9 " 16 510 508 506 504 493 483 446 470 503 495 10 " 17 490 493 496 498 500 502 500 500 501 503 11 " 18 503 502 502 502 503 500 494 490 492 494 12 " 19 496 495 495 492 488 499 506 498 492 501 13 20 514 509 502 506 509 501 491 490 492 498 14 " 21 504 509 517 516 514 512 511 512 512 517 15 " 22 521 529 535 536 529 508 510 516 514 510 16 " 23 511 507 490 491 489 489 488 488 486 485 17 " 0 502 499 496 489 496 500 499 500 484 475 . 18 " 1 456 448 440 435 442 447 451 457 456 449 19 " 2 445 440 425 412 427 438 449 445 440 417 20 3 370 312 284 289 268 298 326 332 360 375 21 " 4 390 400 415 408 405 404 392 396 401 401 22 " 5 404 408 390 375 370 372 — 393 403 402 . 23 " 6 402 407 390 374 370 358 355 370 381 380 0 7 376 377 379 380 382.5 365 370 373 380 395 1 " 8 381 385 372 386 398 406 435 437 438 439 2 " 9 438 438 437 442 446 444 455 448 446 443 3 " 10 450 469 482 497 4 " The series commences with readings 290d, 288d, 282d, at 9h 42m, 48m, and 54m. Value of a scale division O'.SO. Increase of scale readings denotes a movement of the north end of the magnet to the cast. 22 CHANGES OF THE MAGNETIC DECLINATION Gottingen Fern Rock mean time. 0m. 06m. 12m. 18m. 24m. 30m. 36m. 42m. 48m. 54m. mean time. (to Om.) Fern Rock Observatory, March 22 and 23, 1854. Readings taken lm 34s earlier than indicated. 10h 269d 262d 265d 272d 285d 295d 250d 232d 228d 255d 4h37m.5 11 240 261 243 246 232 228 236 260 259 258 5 12 258 256 254 256 258 258 259 260 263 263 6 13 262 253 258 264 263 267 265 256 251 247 7 14 235 237 239 239 240 244 243 247 245 240 8 15 240 238 239 237 234 233 234 237 245 251 9 16 268 265 267 279 280 277 272 264 260 269 10 H 275 279 277 282 279 280 282 284 283 282 11 18 281 280 278 277 275 273 272 270 269 268 12 19 269 268 268 268 267 267 268 266.5 264 262 13 20 261 261 262 261 261 258 258 259 262 265 14 21 269 267 266 264 264.5 262 269 273 278 284 15 22 283 282 278.5 275 270.5 263 265 260 260 261 16 23 260 257 256 250 253 256 248 250 257 263 17 0 272 280 283 285 292 288 289 287 290 294 18 1 300 302 291 290 292 283 277 273 271 J 19 2 — _ — — — 280 284 278 271 269 20 3 267 267 263 255 248 247 252 249 248 251 21 4 260 265 274 292 296 295 298 298 297 295 22 5 291 290 290 293 292 294.5 291 292 288 290 23 6 293 291 291 290 294 295 290 281 276 269 0 7 264 252 250 249 242 239 235 242 252 248.5 1 8 246 245 243 242 240 239 241 244 250 258 2 9 270 282 284 286.5 288 292 297 300 304 302 3 10 301 300 299 4 Fern Rook Observatory, April 19 and 20, 1854. Readings taken 2™ 14s earlier than indicated. 10h 4h37m.5 11 - - - , „_- . — 5 12 , . s- , , L 6 13 __ __ - r -- — 7 14 . . _, , _ __. 8 15 ^_ - ._ .., ,.---., ^_ , ,- — .. -, — 9 16 __ , - 272d 271d 275d 273d 272d.5 278d 282d 10 17 28 9d 299d 298d 312 310 305 301 296 299 262 11 18 271 287 294 290 289 286 280 268 254 230 12 19 236 250 245 242 239 234 229 230 242 256 13 20 265 262 260 256 252 247 243 236 231 228 14 21 225 224 230 236 229 226 231 233 230 227 15 22 226 222 218 215 213 189 187 183 190 187 16 23 184 182 194 220 221 223 218 220 222 225 17 0 231 236 242 236 238 240 235 224 215 203 18 1 194 190 187 184 181 180 178 178 168 164 19 2 175 208 236 242 212 205 202 190 190 193 20 3 194 196 199 200 210 192 180 175 164 152 21 4 140 137 139 148 147 160 164 152 140 121 22 5 107 113 116 136 145 132 130 120 90 63 23 6 + 62 +43 + 30 + 32 ^_ —4 Y + 4 + 8 0 7 + 30 + 23 + 16 + 12 + 16 + 11 +5 —2 + 25 + 58 1 8 71 67 73 77 79 81 75 73 76 80 2 9 75 74 97 110 128 132 138 147 142 134 3 10 126 122 128 132 4 Value of a scale division O'.SO. Increase of scale readings denotes a movement of the north end of the magnet to the east. 1 Watch stopped. AT VAN RENSSELAER HARBOR. 23 Gottingen 1 Fern Rnek mean time. Om. 06m. 12m. 18m. 24m. 30m. 36m. 42m. 48m. 54m. mean time. (to Om.) Fern Rock Observatory, May 26 and 27, 1854. Readings taken lm 34s earlier than indicated. 101' 244d 243d 258d 262d 278d 280d 279d 276d 292d 304d 4h 37m.5 11 330 345 357 365 372 369 365 360 364 368 5 " 12 360 355 345 342 350 348 341 333 330 338 6 " 13 349 356 364 359 354 351 355 360 381 395 7 " 14 403 413 411 408 400 389 395 400. 407 410 8 " 15 414 423 428 436 442 443 442 438 436 433 9 " 16 435 434 440 450 476 490 520 555 570 575 10 " 17 593 600 575 548 533 523 516 506 498 492 11 " 18 485 482 479 477 477 476 475 475 477 480 12 " 19 483 487 493 495 488 495 527 552 568 587 13 " 20 595 612 624 630 633 631 625 620 612 604 14 " 21 599 603 609 612 615 626 633 635 644 650 15 " 22 663 667 665 661 658 659 653 646 640 637 16 " 23 639 641 632 618 595 590 583 572 559 541 17 " 0 543 545 546 546 544 540 537 536 535 537 18 " 1 538 525 523 539 527 520 515 513 480 479 19 " 2 487 493 498 503 506 509 509 533 562 571 20 3 573 553 537 517 495 489 486 488 496 510 21 " 4 512 510 507 513 514 512 511 506 497 487 22 " 5 48(5 485 483 484 480 477 476 476 477 463 23 " 6 449 443 442 440 441 443 447 454 463 470 0 " 7 478 483 487 489 488 483 471 459 457 446 1 " 8 435 447 460 468 475 490 487 478 485 491 2 " 9 493 513 525 530 533 535 534 515 500 — 3 " 10 — 4 " Observations commence at 9'1 24m, scale readings 280d, 271d, 266d, 235d, 231 d, 240d, corre- sponding to 9h 24m, 30m, 36m, 42m, 48m, and 54m respectively. Fern Rock Observatory, June 21 and 22, 1854. Readings taken Im34s earlier than indicated. (Magnet suspended, I. 7.)1 101' 295d 4h37m.5 11 297d 299d 300d 302d 305d 309d 312d 313d 313d 314 5 " 12 315 315 314 314 313 312 310 316 325 333 6 " 13 337 340 344 347 351 352 350 350 351 352 7 " 14 348 346 343 337 333 334 338 348 350 355 8 " 15 354 355 358 364 366 374 374 374 373 367 9 " 16 366 367 366 370 373 377 377 377 378 383 10 " 17 384 385 379 379 379 381 383 384 383 384 11 " 18 387 384 385 382 384 386 386 382 385 387 12 " 19 384 382 383 385 387 386 387 390 392 396 13 " 20 400 402 400 396 394 394 388 376 384 394 14 21 390 383 382 381 379 370 364 368 372 370 15 " 22 367 363 358 355 357 361 367 369 367 364 16 " 23 364 363 361 355 350 350 352 355 359 362 17 " 0 363 363 370 369 367 368 370 363 355 351 18 " 1 348 343 337 335 333 329 330 331 331 328 19 " 2 322 318 320 322 325 327 328 328 326 324 20 " 3 322 318 319 322 323 323 322 324 326 331 21 " 4 326 315 334 330 326 326 319 318 318 318 22 " 5 312 316 318 317 323 321 317 310 312 308 23 " 6 306 320 316 316 318 323 304 303 312 290 0 " 1 291 287 286 286 291 283 275 281 283 288 1 " 8 289 290 292 289 291 293 297 298 302 304 2 " 9 304 309 313 312 308 303 295 290 282 273 3 " 10 264 257 245 283 232 230 234 239 242 228 4 11 212 207 5 " Value of a division of the scale O'.SO. Increase of scale readings denotes a movement of the north end of the magnet to the east. ' This magnet I. 7 was undoubtedly used on all previous occasions. Mark reads on circle 338° 22', circle reads 314° 12'. 24 CHANGES OF THE MAGNETIC DECLINATION The results of the preceding tables have been thrown into curves, to which the corresponding readings at Greenwich and Washington have been added.1 These readings have all been referred to the same scale, and thus present at a glance the great difference in the magnitude of the diurnal motion as well as that of the dis- turbances. The Greenwich observations were taken by means of photography ; the Washington corresponding observations were also obtained by means of Brooke's automatic photographic registration, and have as yet only been published in the 6th volume of the Astronomical Expedition to Chili, under the direction of Lieut. Gilliss, U. S. N. ; Washington, D. C., 1856. For the Greenwich curves the zero line corresponds to 22° west declination. A remarkable absence of disturbances of any magnitude as well as a small diurnal range of motion at the time of the vernal equinox, is shown by the March curves both for Van Rensselaer and Greenwich. There appear to be some disturbances common to both places, and if these indications should not be accidental they are of an opposite character, that is, a magnetic east deflection is presenting itself as a magnetic west deflection at the other station, and vice versa. For this the reader may examine hours 17 and 5£ of the curve for January 18 and 19, hours from 6 to 8, April 20th, and one or two other less striking cases. The needle at Van Rensselaer Harbor actually points with its north end to the south of the astronomical west, and its meridional compo- nent of the direction is pointing in a southern or opposite direction to the same component at Greenwich or Washington. Absolute Declination. — The magnetic declination at Van Rensselaer Harbor was determined on three occasions in the summer of 1854. Two different magnets were used. Determination of June 9th. Magnet A 68, mirror facing magnetic north. Position. Circle reads. Mark. I. 338° 06' 06' II. 338 00 337 59 Means 338 02.8 P. Circle reads. Magnetic meridian (south). I. 316° 01' 00 II. 315 57 56 Mean reading on mark . Astronomical bearing (N.) Reading of meridian (N.) Magnetic meridian (N.) Declination . P. Circle reads. Mark. I. 338° 02' 01 II. 338 05 04 338 03.0 315 58.5 at 6h 35™ Green, t. 338° 03' 93 29 E. 244 34 135 ;V.l 108° 35' W. (of north) at lh 52m P. M. local time. See accompanying plates 1 and 2. AT VAN RENSSELAER HARBOR. 25 Determination of June 14. Magnet I. 10. Mirror facing magnetic north. Magnetic south meridian. I. 317° 10' I. at 5h 12m Gr. t. 09 II. II. 317 02 01 Mark. I. 338° 09 i 08 II. 338 05 04 Means 338 06 .5 317 05.5 Mark. 338° 04' 02 338 09 08 338 05.8 Mean reading on mark . Astronomical bearing (N.) Reading of true meridian Reading of magnetic meridian Declination . . 338° 06' . 93 29 E. . 244 37 . 137 05 . 107° 32' W. at Oh 29m P. M. local time. The magnet showed considerable agitation during the day. Determination of June 26. Mirror facing magnetic north. Magnetic south meridian. I. 315° 49' 47 II. 316 18 17 Means 316 02.7 at lh 3m P. M. local time. Mark. I. 338° 24' 23 II. 338 20 19 338 21.5 Mark reads . Astronomical bearing (N.) N. meridian (true) Magnetic meridian Declination Magnetic south meridian. I. 315° 52' 50 II. 315 40 38 315 45.0 at 2h Om P. M. local time . 338° 21' 93 29 E. 244 52 135 53 . 108° 59' W. at lh 31m P. M. Resulting mean declination (for June 16) 108° 22' W. ; if we omit the 2d determination on account of disturbance, and apply a correction for diurnal change to the mean of the first and last determination, we find 108° 12' W. SECTION II. OBSERVATIONS OF THE MAGNETIC INCLINATION. 1853, 1854, AND 1855. SECTION II. MAGNETIC INCLINATION. Instrument and Remarks. — The observations for dip were made by Mr. Sonntag by means of a Barrow dip circle received from Prof. Henry, of the Smithsonian Institution, through the courtesy of Col. Sabine. The inclinometer was supplied with Lloyd needles, for determining the total intensity, but unfortunately the com- plete record of these observations could not be recovered ; the absence of the record for determining the constants necessary for their reduction being wanted, no use could be made of these observations, even for relative intensity at Saikatle and Marshall Bay, and the partial results given in Appendix XV., vol. II. of the Nar- rative, must, therefore, remain fruitless for the present. There is likewise a defi- ciency in the record of the dip observations at Van Rensselaer Harbor after February 23, 1854; the results, however, are all preserved in the Appendix just mentioned. In regard to the index error of the dipping needles, we can only make an approximate comparison. The observations at New York, where the dip has been represented by the formula I = 72°.69 — 0.00491 (t— 1845) + 0.001 U(t— 1845)2, with a probable error of any single observation1 of ±3'.S, would apparently pro- duce a correction to needle 1 of — 9', and to needle 2 of — 14', the changes, how- ever, from one station to another in the immediate vicinity of the city are much greater, and these quantities may, therefore, as well indicate local deviation as index error. The polarity of the needles has been reversed at each station, the effect of this operation upon the resulting dip is somewhat irregular, and will be found exhibited in tabular form. 1 See Coast Survey Report of 1856, p. 240. The formula includes dip observations taken between December, 1822, and August, 1855 (exclusive of the observations of the present expedition). 30 MAGNETIC INCLINATION STATION No. I. NEW YORK, AT MR. RUTHERFORD'S OBSERVATORY. Latitude 40° 43'.8. Longitude 73° 58'.9. W. of G. May 18, 1853. 4* P. M. Needle No. 2. Poles direct. Magnetic meridian reads 248° 10'. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. 72°°57' 72 56 b 72° 37' 72 35 73° 08' 73 05 t 73° 27' 73 24 72°°51' 72 54 i 72° 52' 72 54 72° 53' 72 56 b 73° 25' 73 29 72 56.5 72 36.0 72 46.2 73 0 73 06.5 73 25.5 73 16.0 1.1 73 ( 72 52.5 72 53.0 72 52.7 73 11.4 72 54.5 73 01.7 73 27.0 10.7 Needle No. 2. Poles reversed. CIRCLE WEST. CIRCLE EAST. Face west. Face east. Face west. Face east. 7203.4 72 56.5 53.5 73 73 35.5 73 49.5 73 42.5 73 09.3 72 57.5 73 18.5 73 08.0 25.2 AT MR. RUTHERFORD'S OBSERVATORY. 31 May 20, 1853. 41-. Needle No. 1. Poles direct. CIRCLE EAST. CIRCLE WE8T.- Face east. Face west. Face east. Face west. 710<37' 71 34 b 72° 00' 71 59 75°° 55' 75 52 b 76° 22' 76 21 a 73 13 b 73° 02' 73 04 a b 73° 41' 74° 04' 73 45 74 06 71 35.5 71 59.5 71 47.5 73 i 75 53.5 76 7.5 76 21.5 07.5 73 73 12.0 73 03.0 73 07.5 73 44.1 73 43.0 74 05.0 73 54.0 30.7 Needle No. 1. Poles reversed. CIRCLE WEST. CIRCLE EAST. Face west. Face east. Face west. Face east. 690<58' 70 00 b 70° 10' 70 13 73°" 17' 73 16 b 72° 52' 72 55 72° 32' 72 30 b 73° 08' 73 06 72° 56' 73° 09' 72 53 73 06 69 59.0 70 11.5 70 05.2 n i 73 16.5 73 ,5.1 72 53.5 05.0 72 72 31.0 73 07.0 72 49.0 72 15.1 72 54.5 73 07.5 73 01.0 35.0 May 20, 1853. Needle No. 1. Poles direct. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. 71°°48' 71 45 b 72° 03' 72 01 74°° 18' 74 17 b 74° 48' 74 45 72°a38' 72 40 b 72° 33' 72 35 • a b 74° 26' 74° 27' 74 29 74 31 71 46.5 71 5 72 02.0 4.2 73 1 74 17.5 74 46.5 74 32.0 3.1 73 72 39.0 72 34.0 72 36.5 73 22.7 74 27.5 74 29.0 74 28.2 32.3 Needle No. 1. Poles reversed. CIRCLE EAST. CIRCLE WEST. Face west. Face east. Face west. Face east. 72° 47' 72 45 * 73° 21' 73 19 73°° 13' 73 11 b 73° 32' 73 30 69° 55' 69 59 b 69° 48' 69 51 Or b »7QO OJ/ >7OO C)Hf 1 a - I 1 a £t\ 72 28 72 29 72 46.0 73 20.0 73 03.0 73 1 73 12.0 73 31.0 73 21.5 2.2 72 69 57.0 69 i L1.2 69 49.5 >3.2 71 72 26.0 72 28.0 72 27.0 [0.1 MAGNETIC INCLINATION STATION No. II. FISKERNAES, FLAGSTAFF NEAR THE GOVERNOR'S HOUSE. Latitude 63° 05'.3. Longitude 50° 34'4. W. of 0». June 29, 1853. Needle No. 2. Poles reversed. Meridian reads 106° 01'. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. a b 80° Of 80° 05' 80 11 80 07 82° OP-' 82 08 b 81° 59' 81 58 80° 28' 80 25 b 80° 36' 80 34 a b 80° 30' 80° 50' 80 28 80 49 80 09.0 80 06.0 82 08.0 81 58.5 80 26.5 80 35.0 80 29.0 80 49.5 80 07.5 82 03.3 80 30.7 80 39.2 81 05.4 80 34.9 80 50.2 Needle No. 2. Poles direct. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. a ' b 80° 47' 80° 38' 80 46 80 41 80°" 28' 80 28 i 80° 29' 80 29 80° 13' 80 10 b 80° 24' 80 22 a b 80° 42' 80° 41' 80 40 80 39 80 46.5 80 39.5 80 43.0 80 28.0 80 80 29.0 28.5 80 11.5 80 80 23.0 17.2 80 41.0 80 40.0 80 40.5 80 35.7 80 28.9 80 32.3 STATION No. III. FISK.ERNAES HARBOR, ON A SMALL ISLAND ON THE NORTH SIDE OF HARBOR. July 1,1853. Needle No. 2. Poles direct. Meridian reads 150° 22'. CIRCLE WEST. CIRCLE EAST. Face west. Face east. Face west. Face east. a b a I a b a b 82° 24' 83° 01' 79° 54' 80° 03' 81° 59' 82° 05' 80° 53' 79° 49' 82 27 83 04 79 57 80 06 81 59 82 03 80 50 79 51 82 25.5 83 02.5 79 55.5 80 04.5 81 59.0 82 04.0 80 51.5 79 50.0 82 44.0 80 00.0 82 01.5 80 20.7 81 22.0 81 11.1 81 16.6 Needle No. 2. Poles reversed. CIRCLE WEST. CIRCLE EAST. Face east. Face west. Face east. Face west. a b a b a b a b 81° 07' 81° 23' 79° 52' 80° 00' 80° 49' 80° 52' 79° 54' 79° 54' 81 11 81 23 79 55 80 02 80 46 80 58 79 53 79 53 81 09.0 81 23.0 79 53.5 80 01.0 80 47.5 80 55.0 79 53.5 79 53.5 81 16.0 79 57.2 80 51.2 79 53.5 80 36.6 80 22.3 80 29.4 AT SUKKERTOPPEN. 33 STATION No. IV. SAIKATLE, ISLAND SOUTH FROM SUKKERTOPPEN. (Latitude and longitude not determined.) The magnetic station was on a small bay on the southeast side of the island, and is covered with water at high tide. The Lloyd needles only were used. STATION No. V. SUKKERTOPPEN, IN THE GARDEN NEAR THE GOVERNOR'S HOUSE. (Latitude and longitude not determined.) July 9, 1853. 15h. Needle No. 2. Poles reversed. Meridian reads 75° 20'. CIRCLE WEST. CIRCLE EAST. Face east. Face west. Face east. Face west. a b a b a b a b 80° 30' 80° 43' 81° 15' 81° 48' 80° 46' 80° 30' 81° 20' 81° 20' 80 28 80 46 81 15 81 45 80 46 80 33 81 20 81 21 80 29.0 80 44.5 81 15.0 81 46.5 80 46.0 80 31.5 81 20.0 81 20.5 80 36.7 81 30.7 80 38.8 81 20.2 81 03.7 80 59.5 81 01.6 Needle No. 2. Poles direct. CIRCLE WEST. CIRCLE EAST. Face east. Face west. Face east. Face west. a b a i a j a b 81° 30' 82° 25' 80° 17' 80° 40' 80° 53' 80° 42' 79° 31' 79° 04' 81 28 82 24 80 14 80 37 80 57 80 45 79 34 79 05 81 29.0 82 24.5 80 15.5 80 38.5 80 55.0 80 43.5 79 32.5 79 04.5 81 50.7 80 27.0 80 49.2 79 18.5 81 11.8 80 03.8 80 37.8 34 MAGNETIC INCLINATION STATION No. VI. PROVEN, GROUND NEAR THE GOVERNOR'S HOUSE. Latitude 72° 25'.9. Longitude 55° 25' (both approximate). July 19, 1853. Needle No. 2. Poles direct. Magnetic meridian 0° 33'. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. 82° 35' 82 34 b 82° 45' 82 44 83°" 16' 83 14 b 83° 19' 83 17 I 82° 38' 82 40 b 82° 41' 82 43. a b 83° 44' 83° 44' 83 47 83 47 82 34.5 82 44.5 82 39.5 82 { 83 15.0 83 .8.0 83 18.0 16.5 83 ( 82 39.0 82 )5.5 82 42.0 40.5 83 83 45.5 83 45.5 83 45.5 13.0 Needle No. 2. Poles reversed. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. 830<15' 83 14 t 83° 14' 83 12 83° 11' 83 10 b 83° 30' 83 28 83° 30' 83 30 b 83° 19' 83 21 a b 82° 14' 82° 23' 82 17 82 25 83 14.5 83 13.0 83 13.7 83 1 83 10.5 83 29.0 83 19.7 6.7 83 ( 83 30.0 83 20.0 83 25.0 82 , )4.5 82 15.5 82 24.0 82 19.8 )2.4 Needle No. 2. Poles direct. Meridian reads 0° 33'. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. 83°°10' 83 08 t 83° 02' 83 01 a 81° 30' 81 30 b 81° 35' 81 34 82°" 22' _ 82 23 b 82° 27' 82 29 a b 83° 28' 83° 41' 83 29 83 44 83 09.0 83 0 83 01.5 81 30.0 5.2 81 , 82 18.7 81 34.5 52.2 82 82 22.5 82 28.0 82 25.2 83 J9.5 83 28.5 83 42.5 83 35.5 00.3 Needle No. 2. Poles reversed. CIRCLE EAST. . CIRCLE WEST. Face east. Face west. Face east. Face west. 83° "l3' 83 15 b 83° 20' 83 19 82°" 57' 82 55 b 82° 52' 82 49 83° 03' $3 05 b 83° 19' 83 20 a b 82° 30' 82° 32' 82 32 82 34 83 14.0 83 19.5 83 16.7 83 ( 82 56.0 82 50.5 82 53.3 15.0 82 i 83 04.0 83 19.5 83 11.7 82 i >8.4 82 31.0 82 33.0 82 32.0 >1.8 AT TJPERNAVIK. 35 STATION No. VII. UPEUNAVIK, STATION IN GARDEN NEAR THE GOVERNOR'S HOUSE. (Latitude and longitude not determined.) July 22, 1853. Needle No. 2. Poles direct. Magnetic meridian reads 239° 18'. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. a b 82° 42' 82° 43' 82 39 82 40 84° 22' .84 21 b 84° 21' 84 18 83° 13' 83 16 I 83° 33' 83 36 a b 83° 59' 84° 12' 84 01 84 14 82 40.5 82 41.5 84 21.5 84 19.5 83 14.5 83 34.5 84 00.0 84 13.0 82.41.0 84 20.5 83 24.5 84 06.5 83 30. 1 83 45.5 83 38.1 Needle No. 2. Poles reversed. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. 84° 15' 84° 40' 84 13 84 37 a 83° 22' 83 20 b 83° 20' 83 18 83° 33' 83 34 ' b 83° 44' 83 45 a b 83° 40' 83° 2f/ 83 42 83 30 84 14.0 84 38.5 83 21.0 83 19.0 83 33.5 83 44.5 83 41.0 83 29.0 84 26.2 83 20.0 83 39.0 83 35.0 83 53.1 83 37.0 83 45.0 STATION No. VIII. BEDEVILLED REACH, FORCE BAY. STATION HALF A MILE EAST OF ANCHORAOE(?). Latitude 78° 34'.5. Longitude 71° 33'.6. August 12, 1853. Needle No. 2. Poles direct. Meridian reads 248° 30'. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. 84° 54' 85° 03' 84 48 84 59 86°° 12' 86 17 b 86° 35' 86 30 84° 16' 84 14 i 84° 17' 84 14 a b 86° 18' 86° 02' 86 19 86 04 84 51.0 85 01.0 86 14.5 86 32.5 84 15.0 84 15.5 86 18.5 86 03.0 84 56.0 86 23.5 84 15.2 86 10.7 85 39.7 85 12.9 85 26.3 Needle No. 2. Poles reversed. CIRCLE WEST. CIRCLE EAST. Face west. Face east. Face west. Face east. a b 84° 15' 84° 04' 84 20 84 10 84° 55' 84 55 b 85° 04' 85 03 84°° 13' 84 09 b 84° 43' 84 38 a b 85° 44' 85° 43' 85 40 85 39 84 17.5 84 07.0 84 12.2 84 55.0 84 85 03.5 59.3 84 11.0 84 84 40.5 25.8 85 42.0 85 41.0 85 41.5 84 35.8 85 03.6 84 49.7 36 MAGNETIC INCLINATION STATION No. IX. NEAR MARSHALL BAY. Latitude 78° 52'. Longitude 69° Ol'.1 The observations on September 3d, 1853, were made with the Lloyd needle, No. 1, Box B. The dip by the statical needle is 85° 26', and the resulting corrected dip 84° 49'. See Narrative, vol. I. p. 99. STATION No. X. VAN RENSSELAER HARBOR, WINTER QUARTERS. MAGNETIC OBSERVATORY ON FERN ROCK. Latitude 78° 37'. Longitude 70° 40'. W. of G. January 26, 1854. Needle No. 2. Poles direct. Magnetic meridian reads on circle 9° 02'. CIRCLE WEST. CHICLE EAST. Face east. Face west. Face east. Face west. a b 83° 05' 83° 02' 83 05 83 03 83° 48' 83 47 b 85° 06' 85 05 82° 53' 82 47 t 82° 30' 82 26 a. b 85° 16' 85° 22' 85 10 85 17 83 05.0 | 83 02.5 83 47.5 85 05.5 82 50.0 82 28.0 85 13.0 85 19.5 83 03.7 84 26.5 82 39.0 85 1G.2 83 45.1 83 57.6 83 51.3 Needle No. 2. Poles reversed. CIRCLE WEST. CIRCLE EAST. Face east. Face west. Face east. Pace west. a b 84° 48' 85° 22' 84 48 85 23 84°%9' 84 15 * 84° 40' 84 39 86° 20' 86 15 i 86° 05' 86 00 84° 27' 85° 20' 84 21 85 16 84 48.0 85 22.5 84 12.0 84 39.5 86 17.5 86 02.5 84 24.0 85 18.0 85 05.2 84 25.8 86 10.0 84 51.0 84 45.5 85 30.5 85 08.0 1 Erroneously given 67° 01' in the Narrative, vol. II. p. 431; the date should also be changed as given above. AT VAN RENSSELAER HARBOR. 37 February 16, 1854; Needle No. 2. Poles direct. Meridian reads 69° 30'. CIRCLE WEST. CIRCLE EAST. Face west. Face east. Face west. Face east. 85°°38' 85 38 b 86° 02' 86 02 84°%!' 84 41 b 84° 30' 84 28 85*24' 85 23 b 85° 38' 85 39 83°° 51' 83 56 b 83° 44' 83 44 85 38.0 86 02.0 85 50.0 85 ] 84 41.0 84 29.0 84 35.0 2.5 84 85 23.5 85 38.5 85 31.0 84 36.2 83 53.5 83 39.9 83 44.0 48.7 Needle No. 2. Poles reversed. CIRCLE WEST. CIRCLE EAST. Face west. Face east. Face west. Face east. 84 30 b 84° 25' 84 23 84° 53' 84 52 b 84° 49' 84 49 84° 35' 84 36 b 84° 33' 84 33 85° 11' 85 13 b 85° 38'. 85 38 84 29.0 84 24.0 84 26.5 84 I 84 52.5 84 49.0 84 50.7 8.6 84 84 35.5 84 19.1 84 33.0 34.2 84 85 12.0 85 i 39.6 85 38.0 5.0 February 23, 1854. Needle No. 2. Poles reversed. Magnetic meridian 67° 35'. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. 85 26 b 85° 35' 85 30 85° 11' 85 06 85° 14' 85 10 85°* 06' 85 08 b 85° 04' ' 85 07 84° 26' 84 27 b 84° 12' 84 14 85 28.0 85 32.5 85 30.2 85 2 85 08.5 85 12.0 85 10.2 0.2 85 ( 85 07.0 85 05.5 85 06.2 84 11.0 84 26.5 84 43.0 84 13.0 19.8 Needle No. 2. Poles direct. CIRCLE EAST. CIRCLE WEST. Face east. Face west. Face east. Face west. 840<27' 84 24 b 84° 08' 84 04 85°" 01' 84 57 b 85° 21' 85 18 84° 28' 84 29 84° 12' 85°° 06' 84 14 85 07 b 85° 13' 85 15 84 25.5 84 06.0 84 15.7 84 4 84 59.0 85 19.5 85 09.3 2.5 84 84 28.5 84 13.0 84 20.7 84 ' 14.0 85 06.5 85 14.0 85 10.2 15.4 38 RECAPITULATION OF RESULTS. RECAPITULATION OF RESULTS FOR MAGNETIC INCLINATION. No. of station. Locality. Date. No. of needle. DIP. Difference for change of polarity. Mean and resulting dip. Pole direct. Pole reversed. I. New York city May 18, 1853 2 73° 01'.4 72° 46'.8 + 14'.6 72° 54'.1] ti u a ( ( tt 2 73 09.3 72 54.6 + 14.7 72 61'9 7" 55' 6 tt n it May 20, 1 73 44.1 72 15.1 + 89.0 f- 1 £ Ou . D 72 59.6 | (( a n ti 1 73 22.7 72 11.2 + 71.5 72 47.0 J II. Fiskernaes June 29, 2 80 32.3 80 50.2 —17.9 80 41.3 III. Fiskernaes Harbor July 1, 2 81 16.6 80 29.4 + 47.2 80 53.0 IV. Saikatle July 9, LI. (Approx imatc.) — 80 56.0 Y. Sukkertoppen July 9, 2 80 37.8 81 01.6 —23.8 80 49.7 VI. Proven July 19, 2 83 05.5 83 04.5 + 1.0 83 05.0 82 57.0 (( n II 2 82 39.5 82 58.4 —18.9 82 49.0 VII. Upernavik July 22, 2 83 38.1 83 45.0 — 6.9 83 4]. 5 ' VIII. Bedevilled Reach Aug. 12, 2 85 26.3 84 49.7 +36.6 85 08.0 IX. Marshall Bay Sept. 3, LI. (Approx imate.) — 84 49.0 X. Fern Rock Obser- vatory, Van Rens- selaer Harbor Jan. 26, 1854 2 83 51.3 85 08.0 —76.7 84 29.7 Feb. 16, ' 2 84 56.2 84 49.1 + T.l 84 52.6 Feb. 23, ' 2 84 44.0 85 01.6 —17.6 84 52.8 March 2, ' 2 — — — 84 49.0 84 45.8 June 10, ' 2 — — — 84 47.2 tt l 2 — — _ 84 51.0 April 24, 1855 2 (12 sets.) — 84 48.7 May 20, " 2 — • — — 84 35.6 The resulting dip at Van Rensselaer Harbor may be taken as corresponding in time to June, 1854. SECTION III. OBSERVATIONS OF MAGNETIC INTENSITY. 1854 AND 1855. SECTION III. OBSERVATIONS AND DISCUSSION OF THE MAGNETIC INTENSITY. THE instrument used (a unifilar magnetometer) has already been described. For the determination of the intensity, the long magnet A. 67 has exclusively been used for oscillations and deflections. The effect of the torsion in the sus- pension was found so small that it was neglected. The vibrations have been observed in sets of two, one containing the readings of the chronometer when the magnet was moving in the direction of the scale readings, and the other when the magnet was moving in the opposite direction.1 A mean time pocket chronometer was generally used for noting the time, and its rate was too small to affect sensibly •the duration of a single vibration. In the deflections, the magnets were always kept at right angles to one another; the distance of the middle of the deflecting magnet, A. 67, from the suspended magnet, is given by a scale divided into feet and decimals of a foot.2 The observations were made by Mr. A. Sonntag. At Van Rensselaer Harbor the observations extend over the time from January, 1854, to May, 1855. Two other stations were occupied, one in June, 1855, at Hakluyt Island, the other in July, on the coast between Parker Snow Point and Cape York, at the return of the party. The necessary constants have been determined at Washington, D. C. Magnet A. 67 is nearly three inches in length, the two other magnets, I. 7 and I. 10, are somewhat shorter. 1 The vibrations given in the Narrative, vol. II., Appendix, No. XV., pp. 431 — 434, are, therefore, double vibrations, and should have been noted as such. 3 By some inadvertence, Appendix No. XV. of vol. II. of the Narrative contains the distances ex- pressed in inches; it should have been given in feet and decimals, thus, 13 inches should be 1.3 feet, and 9 inches should read 0. 9 feet. 42 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY January 17, 1854. Fern Rock Observatory, Van Rensselaer Harbor. A. 67 suspended. Experiments of vibrations. (From right to left.) No. Time by pocket chronometer. No. Time by pocket chronometer. Time of 45 double vibrations. 1 2 3 4 5 6 7 8 9 10 5h 58m 378.3 52.9 59 08.0 23.8 38.7 54.5 6 00 09.9 25.9 40.2 55.8 46 47 48 49 50 51 52 53 ' 54 55 6h l()rn 10«.8 26.3 41.4 57.0 11 12.7 28.0 43.3 58.4 12 14.0 29.6 llm 33s. 5 33.4 33.4 33.2 34.0 33.5 ' 33.4 32.5 33.8 33.8 Mean Ilm338.45 Arc at beginning 4° 40'. Temp. 50°. Time of 2 vibrations " end 1 28 15". 410. The vibrations from left to right could not be observed. January 18, 1854. Fern Rock Observatory. Experiments of vibrations. (From right to left.) No. Time by pocket chronometer. No. Time by pocket chronometer. Time of 50 double vibrations. 1 2 3 4 5 6 7 8 9 10 11 5h 30m 43S.Q 58.8 31 14.0 29.3 44.4 ' 32 00.0 15.3 31.5 46.5 33 02.0 18.1 51 52 53 54 55 56 57 58 59 60 61 51' 43m 37s. 5 53.8 44 08.8 23.9 39.8 54.0 45 10.8 25.8 41.8 57.0 46 12.5 12m 54.5 55.0 54.8 54.6 55.4 54.0 55.5 54.3 55.3 55.0 54.5 12 54.81 Arc at beginning 4° 40'. Temp. 68. Time of 2 vibrations " end 1 12 15". 496. January 18, 1854. Fern Rock Observatory. Experiments of vibrations. (From left to right.) No. Time by pocket chronometer. No. Time by pocket chronometer. Time of 50 double vibrations. 1 2 3 4 5 6 7 8 9 10 11 5h 30ra 50».8 31 06.7 22.0 36.9 52.9 32 08.0 23.8 39.2 54.8 33 10.3 26.0 51 52 53 54 55 56 57 58 59 60 61 51. 43m 468. 7 44 02.0 18.4 32.7 49.0 45 04.8 20.0 35.3 51.0 46 07.0 22.2 12ra 55s. 9 55.3 56.4 55.8 56.1 56.8 56.2 56.1 56.2 56.7 56.2 12 56.15 Arcs and temp, as before. Time of 2 vibrations 15". 523. (Dr. Hayes assisted in these observations.) AT VAN RENSSELAER HARBOR. 43 February 21, 1854. Fern Rock Observatory. Experiments of vibrations. (From right to left.) No. Time by pocket chronometer. No. Time by pocket chronometer. Time of 50 double vibrations. 1 2 3 4 5 6 7 8 9 10 11 4h 59m 26s. 0 41.8 56.4 5 00 12.6 28.2 43.5 58.9 01 14.6 302 45.6 02 01.3 51 52 53 54 55 56 57 58 59 60 61 5h I2m238.5 39.4 55.0 13 10.2 26.2 41.5 57.3 14 12.8 28.3 43.5 59.2 12m 57.5 57.6 58.6 57.6 58.0 58.0 58.4 58.2 58.1 57.9 57.9 12 57.98 Arc at beginning 5° 52'. Temp. 79°. Time of 2 vibrations " end 2 24 158.560. Experiments of vibrations. (From left to right.) No. Time by pocket chronometer. No. Time by pocket chronometer. Time of 50 doable vibrations. 1 2 3 4 5 6 7 8 9 10 11 4h 59m338.5 48.3 5 00 04.8 20.4 35.7 51.2 01 06.9 22.5 38.0 53.5 02 09.5 51 52 53 54 55 56 57 58 59 60 61 5h 12m318.8 47.1 13 02.8 18.4 34.0 49.5 14 05.2 20.8 36.2 .51.7 15 07.4 12™ 588.3 58.8 58.0 58.0 58.3 58.3 58.3 58.3 58.2 58.2 57.9 12 58.24 Arcs and temp, as before. Time of 2 vibrations 15s. 565. February 21, 1854. Fern Rock Observatory. Experiments of vibrations. (From right to left.) No. Time by pocket chronometer. No. Time by pocket chronometer. Time of 50 double vibrations. 1 2 3 4 5 6 7 8 9 10 6h 20m47".5 21 03.0 19.0 34.3 49.5 22 05.5 20.9 36.3 51.5 23 07.0 51 52 53 54 55 56 57 58 59 60 6h 33m 429. 6 58.0 34 14.0 29.6 45.0 35 00.3 16.8 32.0 47.0 36 03.7' 12m 55.1 55.0 55.0 55.3 55.5 54.8 55.9 55.7 55.5 56.7 12 55.45 Arc at beginning 5° 20'. Temp. 55°. Time of 2 vibrations " end 1 36 15s. 509. Corrected by 10s 44 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY February 21, 1854. Fern Rock Observatory. Experiments of vibrations. (From left to right.) No. Time by pocket chronometer. No. Time by pocket chronometer. Time of 50 double vibrations. 1 6h 20m 55s. 2 51 6h 33m518.0 12m 55.8 2 21 11.0 52 34 06.5 55.5 3 27.0 53 22.6 55.6 4 . 42.0 54 37.5 55.5 5 57.5 55 53.4 55.9 6 22 13.3 56 35 08.6 55.3 7 29.0 57 25.0 56.0 8 . 43.8 58 39.6 55.8 9 59.2 . 59 55.5 56.3 10 23 15.3 60 36 12.0 ' 56.7 12 55.84 Arcs and time as before. Time of 2 vibrations 15s. 517. RECAPITULATION OF RESULTS. January 17, 1854. Time of 2 vibrations 15'. 410 Temp. 50° " 18, " " " 15.496) " 68 ) " 18, " " " 15.523) " 68 j February 21, " 21, " " " 15.560") " 79 ) 15.565 j " 79 j 21, " 15.509) " 55 ) 21, " " " 15.5173 " 55 J Combination by two means 15.499 63.0 Time of one vibration 7.749 January 31, 1854. Experiments of deflections. Distance 1.3 feet. Deflecting magnet A 67. Magnet. North pole. Circle reads. Mean. Diff. or 2 u. Temp. E. W. 318° 40' 41 40'.5 68° ii E. 287 57 57 57.0 30° 43'.5 73 W. E. 288 47 47 47.0 75 ii W. 319 37 37 37.0 30 50.0 72.5 Means 30 46.7 72.1 February 13, 1854. Experiments of deflections. Distance 0.975 feet. Magnet. North pole. Circle reads. Mean. 2u. Temp. E. E. 162° 07' 06'.5 50° ii W. 06 83 10 10 10.0 78° 5C/.5 Cl W. W. 86 24 24.0 65 11 E. 24 164 47 47 47.0 78 23.0 66 Means 78 40.0 60.5 AT VAN RENSSELAER HARBOR. 45 February 27, 1854. Experiments of deflections. Distance 1.3 feet. Magnet. North pole. Circle reads. Mean. 2 u. Temp. E. E. 140° 54'.5 ,,,, 54.5 54'5 W. 109 58 ,8 , 59 W. W. 110 31 Q1 , 32 81-B K Ul {I 15.0 58° 30° 56'.0 58 58 30 43.5 56 30 49.7 5T.5 June 7, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 45 double vibrations. 1 2 3 4 5 6 7 8 9 10 Rat 3h 04m348.2 49.4 05 05.0 20.3 35.8 51.1 06 06.3 21.8 36.9 52.1 46 47 48 49 50 51 52 53 54 55 3h 16m 02". 5 17.8 33.0 48.3 17 03.6 19.0 34.2 49.4 18 04.8 20.0 Ilm28s.3 284 28.0 28.0 27.8 27.9 27.9 27.6 27.9 27.9 11 27.97 Arc at beginning 6° 8'. Temp. +33°. Time of 2 vibrations 15s. 288. " end 2 48 e of mean time chronometer 2721 (showing nearly Greenwich time), about 2s. 0 losing. June 7, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 45 double vibrations. 1 2 3 4 5 6 7 8 9 10 57.6' 05 12.7 28.1 43.3 58.8 06 13.8 29.2 44.4 07 00.0 46 47 48 49 50 51 52 53 54 55 3h 16m108.2 25.5 40.8 56.0 17 11.2 26.5 41.9 57.4 18 12.5 27.8 llm 27s. 9 27.9 28.1 27.9 27.9 27.7 28.1 28.2 28.1 27.8 11 27.96 Arcs and temp, as before. Time of 2 vibrations 15 ".288. 46 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY Jane 7, 1854. Experiments of vibrations. (Left to right.) • No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 45 double vibrations. 1 2 3 4 5 6 t 8 9 10 3h 22m 08s. 0 28.3 38.5 53.8 23 09.2 24.5 39.7 55.0 24 10.3 25.7 46 47 48 49 50 51 52 53 54 55 3h 33m378.0 52.3 34 07.6 23.0 ' 38.2 53.7 35 09.0 24.5 39.6 54.9 llm 29s. 0 29.0 29.1 29.2 29.0 29.2 29.3 29.5 29.3 29.2 11 29.18 Arc at beginning 6° 8'. Temp. 33°. Time of 2 vibrations 15s. 315. " end 2 48 June 7, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 2721. No. Time ty chronometer 2721. Time of 45 double vibrations. 1 2 3 4 5 6 7 8 9 10 3h 22m16s.O 31.2 46.3 23 01.8 17.0 32.3 47.8 24' 03.1 18.3 33.3 46 47 48 49 50 51 52 53 54 55 3U 33m458.0 34 00.2 15.5 30.9 46.3 35 01.5 16.8 32.2 47.3 36 02.5 llm 298.0 29.0 29.2 29.1 29.3 29.2 29.0 29.1 29.0 29.2 11 29.11 Arcs and temp, as before. Time of 2 vibrations 15*. 313. June 7, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 2721. No. Time by chronometer 2721. 1 Time of 54 double vibrations. 1 2 3 4 5 6 7 8 9 10 8h 12">398.1 54.5 13 09.8 25.1 40.3 56.0 14 11.3 26.5 42.1 57.5 55 56 57 58 59 60 61 62 63 64 8h 26m 30s. 7 46.0 27 01.5 17.0 32.2 47.8 28 03.2 18.8 34.0 49.3 13m 51s. 6 51.5 51.7 51.9 51.9 51.8 51.9 52.3 51.9 51.8 13 51.83 Arc at beginning 6° 40'. Temp. 35. Time of two vibrations 15s. 403. " end 2 56 AT VAN RENSSELAER HARBOR. 47 June 7, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 54 double vibrations. 1 gh 12m 46*. 8 55 gh 26m 3gs 5 13ra518.7 2 13 02.0 56 54.0 52.0 3 17.2 57 27 09.3 52.1 4 32.6 58 24.8 52.2 5 48.1 59 40.3 52.2 6 14 03.3 60 55.7 52.4 7 if. 7 61 28 11.1 52.4 8 34.0 62 26.4 52.4 9 49.5 63 41.9 52.4 10 15 05.0 64 57.4 . 52.4 13 52.22 Arcs and time as before. Time of 2 vibrations 15s. 412. June 7, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 50 double vibrations. 1 gh 35m If 8.1 51 8h 48m078.8 12m 508.7 2 32.2 52 23.1 50.9 3 48.0 53 38.6 50.6 4 36 03.3 54 54.0 50.7 5 19.0 55 49 09.3 50.3 6 34.3 56 24.8 50.5 7 49.6 57 40.1 50.5 8 37 05.1 58 55.6 50.5 9 20.6 59 50 10.9 50.3 10 36.2 60 26.3 50.1 11 51.5 61 41.6 50.1 12 50.47 Arc 7° 28'. Temp. 35°. Time of 2 vibrations 15s. 409. 3 12 Jane 7, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 50 double vibrations. 1 8h 35m248.7 51 8h 48™ 15s. 2 12™ 50s. 5 2 40.0 52 30.7 50.7 3 55.2 53 46.0 50.8 4 36 10.8 54 49 01.3 50.5 5 26.2 55 16.8 50.6 6 42.0 56 32.2 50.2 7 57.2 57 47.7 50.5 8 37 12.7 58 50 03.0 50.3 9 28.3 59 18.7 50.4 10 43.8 60 33.8 50.0 11 59.0 61 49.2 50.2 12 50.43 Arcs and temp, as before. Time of 2 vibrations 15s. 409. 48 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY Set No. 1. Time of 2 vibrations Set No. 2. " " Set No. 3. Set No. 4. " " June 7, 1854. RECAPITULATION OF RESULTS, JUNE t, 1854. 15s. 288 Temp. 33° 15.288 " 33 15.315 " 33 15.313 " 33 15.403 " 35 15.412 " 35 15.409 " 35 15.409 * " 35 4-34.0 Mean Time of 1 vibration . 15.355 7.678 June 7, 1854. Experiments of deflections. Deflecting magnet A. 67. Deflected magnet I. 10. Distance 0.9 feet. w. w. North pole. E. W. W. E. Circle read?. 374° 16'.3 15.0 265 55.0 54.0 260 58.0 55.5 368 31.0 30.0 Mean. 15'.7 545 56.7 30.5 2u. 108° 21'.2 107 33.8 Means 107 57.5 Temp. 36°.2 38.0 36.0 34.0 36.0 Experiments of deflections. Distance 1.3 feet. Magnet. E. W. North pole. E. W. W. E. Circle reads. 331° 33'.0 31.0 300 34.0 33.0 301 01.0 00.0 332 37.0 35.0 Mean. 32'.0 33.5 00.5 36.0 2u. 30° 58'.5 31 35.5 Means 31 17.0 Temp. 34°.5 34.3 35.8 35.0 34.9 These two sets of deflections were observed between the second and third set of the preceding vibrations. AT VAN RENSSELAER HARBOR. 49 June 8, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 40 double vibrations. 1 3h 16m 20s. 0 41 3h 26m408.4 10m20s.4 2 35.5 42 56.0 20.5 3 50.9 43 27 11.5 20.6 4 17 06.5 44 27.2 20.7 5 22.2 45 42.6 20.4 6 37.8 46 58.1 20.3 7 53.3 47 28 13.5 20.2 8 18 08.8 48 29.1 20.3 9 24.3 49 44.6 20.3 10 39.8 50 29 00.5 20.7 11 55.2 51 15.5 20.3 * 10 20.43 Arcs 5° 30'. Temp. 35°. Time of 2 vibrations 15". 511. 3 20 June 8, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 40 double vibrations. 1 3h 16m 27s. 3 41 3h 26m48s.O 10m20s.7 2 43.2 42 27 03.5 20.3 3 58.6 43 19.0 20.4 4 17 14.2 44 34.6 20.4 5 29.7 45 50.0 20.3 6 45.3 46 28 05.6 20.3 7 18 00.8 47 21.1 20.3 8 16.2 48 36.5 20.3 9 31.8 49 52.2 20.4 10 47.3 50 29 07.6 20.3 11 19 02.9 51 23.3 20.4 10 20.37 Arcs and temp, as before. Time of 2 vibrations 15s. 509. June 8, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 40 double vibrations. 1 3h 31m 338 3 41 3h 41m53s.9 10m 20s. 6 2 49.0 42 42 09.2 20.2 3 32 04.5 43 24.7 20.2 4 20.0 44 40.2 20.2 5 35.6 45 55.8 20.2 6 51.2 46 43 11.2 20.0 7 33 06.7 47 26.7 20.0 8 22.1 48 42.1 20.0 9 37.6 49 57.7 20.1 10 53.1 50 44 13.0 19.9 11 34 08.3 51 28.5 20.2 10 20.15 Arcs 6° 8'. Temp. 35°. 2. Time of 2 vibrations 15s. 503. and 3 12 50 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY June 8, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 40 double vibrations. 1 3h 31m40s.8 41 3h 42m 01s. 2 10'" 20s. 4 2 56.4 42 16.5 20.1 3 32 11.9 43 32.2 20.3 4 27.3 44 47.5 20.2 5 43.1 45 43 03.0 19.9 6 58.6 46 18.4 19.8 7 33 14.1 47 33.9 19.8 8 29.6 48 49.4 19.8 9 45.1 49 44 04.9 19.8 10 34 00.7 50 20.3 19.6 11 16.2 51 35.8 19.6 10 19.93 Arcs and temp, as before. Time of 2 vibrations 15s. 4 9 8. (4 sets of deflections were taken after the above, for which see below.) June 8, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 2721. No. Time by chronometer 2721. 1 Time of 40 double vibrations. 1 gh 3lm54B 3 41 gh 42m 09 8. 5 10m 15s. 2 2 32 10.2 42 24.9 14.7 3 25.3 43 40.2 14.9 4 40.8 44 55.5 14.7 5 56.2 45 43 10.9 14.7 6 33 11.4 46 26.2 14.8 7 27.0 47 41.7 14.7 8 42.3 48 56.9 14.6 9 57.4 49 12.3 14.9 10 34 13.1 50 27.5 14.4 11 28.3 51 42.9 14.6 10 14.75 Arcs 6° 48'. Temp. 35°. Time of 2 vibrations 15".3G9. and 2 08 June 8, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 40 double vibrations. 1 gl, 32m 02 ». 3 41 gh 42m 18s. 3 10™ 16.0 2 17.8 42 33.6 15.8 3 33.2 43 49.0 15.8 4 48.7 44 43 04.4 15.7 5 33 04.0 45 19.9 15.9 6 19.3 46 35.2 15.9 7 34.8 47 50.6 15.8 8 50.2 48 44 06.0 15.8 9 34 05.5 49 21.4 15.9 10 21.2 50 36.9 15.7 11 36.8 51 52.3 15.5 10 15.80 Arcs and temp, as before. Time of 2 vibrations 158.395. AT VAN RENSSELAER HARBOR. 51 June 8, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 40 doable vibrations. 1 2 3 4 5 6 1 8 9 10 11 8h 48" 49 50 51 52".0 07.3 23.0 38.2 53.4 08.9 24.3 39.6 54.7 10.1 25.3 41 42 43 44 45 46 47 48 49 50 51 8h 59" 9 00 04s. 6 19.7 35.3 50.5 05.8 21.1 36.3 51.6 07.0 22.2 37.5 10" 12s. 6 12.4 12.3 12.3 12.4 12.2 12.0 12.0 12.3 12.1 12.2 10 12.25 Arcs 6° 5G'. and 3 20 Temp. 35°. Time of 2 vibrations 15s. 306. June 8, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 2721. No. Time by chronometer 2721. Time of 40 double vibrations. 1 2 3 4 5 6 7 8 9 10 11 8h 48 49 50 51 598.8 15.1 30.3 45.8 01.1 16.3 31.8 47.2 02.2 17.8 33.0 41 42 43 44 45 46 47 48 49 50 51 8h 59" 9 00 01 12s. 0 27.5 42.8 58.0 13.4 28.6 43.9 59.3 14.6 29.9 45.3 10m128.2 12.4 12.5 12.2 12.3 12.3 12.1 12.1 12.4 12.1 12.3 10 12.26 Arcs and temp, as before. Time of 2 vibrations 15s. 306. Daily rate of chronometer 2721, losing 18.0. RECAPITULATION OF RESULTS, JUNE 8, 1854. Set No. 1. Time of 2 vibrations Set No. 2. " " Set No. 3. , " " Set No. 4. " " Means Time of 1 vibration 15s. 511 15.509 15.503 15.498 15.369 15.395 15.306 15.306 15.425 7.712 Temp. 35° " 35 " 35.2 " 35.2 " 35 " 35 " 35 " 35 35.0 The following deflections correspond in time to the middle of the above vibration results. 52 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY June 8, 1854. Experiments of deflections. Deflecting magnet A. 67. Deflected magnet I. 10. Distance 1.3 feet. Magnet. North pole. Circle reads. Mean. 2 u. Temp. w. E. 329° 46' 45'.5 36°.7 u W. 45 298 36 34 350 31° 10'.5 37.7 E. W. 298 08 07.0 37.0 u E. 06 329 41 40 40.5 31 33.5 36.2 Means 31 22.0 36.9 Experiments of deflections. Distance 0.9 feet. Magnet. North pole. Circle reads. Mean. 2u. Temp. E. E. 365° 52'.5 K1 A 51'.7 37°.2 tl W. 254 54 53 53.5 110° 58'. 2 36.6 W. W. 262 30 Oft 29.0 37.0 n E. 369 08 06 07.0 106 38.0 37.0 Means 108 48.1 36.9 Experiments of deflections. Distance 0.9 feet. Magnet. North pole. Circle reads. Mean. 2u. Temp. W. E. 369° OS'.O 07'.2 37°.2 H W. 06.5 262 20 19.0 106° 48'.2 37.0 18 E. W. 254 41 40 40.5 37.6 n E. 364 48.0 46.5 47.2 110 06.7 36.6 Means 108 27.4 37.1 Experiments of. deflections. Distance 1.3 feet. Magnet. North pole. Circle reads. Mean. 2u. Temp. E. E. 328° 52' 52'.0 36°.0 It W. 52 297 23 22 22.5 31° 29'.5 35.2 W. W. 298 03 02 02.5 36.3 it E. 329 13 13 13.0 31 10.5 37.0 Means 31 20.0 36.1 AT VAN RENSSELAER HARBOR. 53 June 19, 1854. Experiments of deflections. Deflecting magnet A. 67. Deflected magnet I. 7. Distance 0.9 feet. Magnet. North pole. Circle reads. Mean. 2u. Temp. w. E. W. E. E. W. 268° 50' 49 3T6 23 22 373 05 04 267 00 266 59 49'. 5 22.5 04.5 59.5 107° 33'.0 106 05.0 Means 106 49.0 Experiments of deflections. Distance 1.3 feet. 40°.6 41.6 41.2 41.2 41.1 Magnet. North pole. Circle reads. Mean. 2u. Temp. E. W. W. E. E. W. 303° 38' 37 334 21 20 334 46 46 304 04 03 37'.5 20.5 46.0 03.5 30° 43'.0 30 42.5 Means 30 42.7 41.0 43.5 43.0 42.1 June 19, 1854. Experiments of vibrations. (Left to right.) No. Time.i No. Time." Time of 40 double vibrations. 10 11 33" 34 35 20s. 1 35.3 51.0 06.5 21.9 37.3 52.8 08.3 23.8 39.3 54.9 Arcs 7° 28'. and 3 44 41 42 43 44 45 46 47 48 49 50 51 Temp. 43C 4h 43'" 38s. 6 54.0 44 09.5 25.0 40.4 55.9 45 11.2 26.6 42.1 57.7 46 13.0 10m18".5 18.7 18.5 J8.5 18.5 18.6 18.4 18.3 18.3 18.4 18.1 10 18.44 Time of 2 vibrations 15 ". 461. Number of chronometer not stated. 54 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY June 19, 1854. Experiments of vibrations. (Right to left.) No. Time. No. Time. Time of 40 double vibrations. 1 4h 33m 28«.2 41 4" 43m468.8 10m 18s. 6 2 43.4 42 44 02.3 18.9 3 59.0 43 17.8 18.8 4 34 14.3 44 33.2 18.9 5 29.9 45 48.6 18.7 6 45.3 46 45 04.2 18.9 T 35 00.9 47 19.5 18.6 8 16.3 48 35.1 18.8 9 31.9 49 50.4 18.5 10 47.2 50 46 05.8 18.6 11 36 02.8 51 21.4 18.6 10 18.72 Arcs and temp, as before. Time of 2 vibrations 15s. 463. Experiments of vibrations. (Left to right.) No. Time. No. Time. Time of 40 double vibrations. 1 4h 50m 268.2 41 5h O0m448.0 10m 178.8 2 41.8 42 59.3 17.5 3 57.3 43 01 14.8 17.5 4 51 12.9 44 30.3 17.4 5 28.2 45 45.9 17.7 6 43.5 46 02 01.3 17.8 7 59.1 47 16.7 17.6 8 52 14.5 48 32.2 17.7 9 29.9 49 47.7 17.8 10 45.4 50 03 03.2 17.8 11 53 01.0 51 18.8 17.8 10 17.67 Arcs 6° 56'. Temp. 43°. Time of 2 vibrations 158.442. and 4 00 Experiments of vibrations. (Right to left.) No. Time. No. , Time. Time of 40 double vibrations. 1 4h 50m 348.! 41 5h 00m51».6 10m 17s. 5 2 49.5 42 01 07.1 17.6 3 51 04.9 43 22.4 17.5 4 20.3 <4 37.9 17.6 5 35.9 45 53.4 17.5 6 51.2 46 02 08.9 17.7 1 52 06.9 47 24.3 17.4 8 22.2 48 39.6 17.4 9 37.8 49 55.0 17.2 10 53.1 50 03 10.3 17.2 11 53 08.6 51 25.8 17.2 10 17.44 Arcs and temp, as before. Time of 2 vibrations 15s. 436. AT VAN RENSSELAER HARBOR. 55 June 19, 1854. Experiments of vibrations. (Left to right.) No. Time. No. Time. Time of 40 double vibrations. 1 2 3 4 5 6 7 8 9 10 11 5h 13m 12s. 2 27.9 43.3 58.9 14 14.2 29.5 45.1 15 00.3 16.1 31.3 46.9 41 42 43 44 45 46 47 48 49 50 51 5h 23m 30s. 3 45.7 24 01.2 16.8 32.3 47.9 25 03.4 18.9 34.1 49.7 26 05.1 10m 18s. 1 17.8 17.9 17.9 18.1 18.4 18.3 18.6 18.0 18.4 18.2 10 18.15 Arcs 6° 48'. Temp. 42°.4. Time of 2 vibrations 15s. 454. 3 36 Experiments of vibrations. (Right to left.) No. Time. No. Time. Time of 40 doable vibrations. 1 2 3 4 5 6 7 8 9 10 11 5» 13m 20s. 2 35.7 51.2 14 06.5 22.1 37.5 53.2 15 08.4 23.7 39.2 54.8 41 42 43 44 45 46 47 48 49 50 51 5h 23m37s.6 52.9 24 08.3 24.0 39.5 54.9 25 10.2 25.2 40.8 56.5 26 11.7 10m17s.4 17.2 17.1 17.5 17.4 17.4 • 17.0 16.8 17.1 17.3 16.9 10 17.19 Arcs and temp, as before. Time of 2 vibrations 15s. 430. Experiments of vibrations. (Left to right.) No. Time. No. Time. Time of 40 donble vibrations. 1 2 3 4 5 6 7 8 9 10 11 5h 33m 23s. 3 38.9 54.2 34 09.5 25.2 40.4 55.9 35 11.2 26.8 42.2 57.6 41 42 43 44 45 46 47 48 49 50 51 51, 43,1. 393.5 54.9 44 10.3 25.8 41.3 56.7 45 11.9 27.4 42.8 58.2 46 13.6 10m 16s. 2 16.0 16.1 16.3 16.1 16.3 16.0 16.2 16.0 16.0 16,ft 10 W.\l Arcs 7° 04'. Temp. 42°.4. Time of two vibrations 15". 403, 3 28 56 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY Experiments of vibrations. (Right to left.) No. Time. No. Time. Time of 40 double vibrations. 1 5h 33m318.2 41 5h 43">478.2 10'" 16s. 0 2 46.5 42 44 02.8 16.3 3 34 02.1 43 18.1 16.0 4 17.4 44 33.5 16.1 5 33.0 45 49.0 16.0 6 48.4 46 45 04.5 16.1 7 35 03.7 47 19.8 1G.1 8 19.0 48 35.2 16.2 9 34.3 49 50.6 16.3 10 49.5 50 46 05.9 16.4 11 36 05.2 51 21.3 16.1 10 16.15 Ares and temp, as before. Time of 2 vibrations 15s. 404. RECAPITULATION OF RESULTS, JUNE 19, 1854. Set No. 1. Time of 2 vibrations .... 15". 461 Temp. 43° 15.463 " 43 Set No. 2. . 15.442 " 43 15.436 " 43 Set No. 3. . 15.454 " 42.4 15.430 " 42.4 Set No. 4. . 15.403 " 42.4 15.404 " 42.4 Means .... 15.437 42.7 Time of 1 vibration . . 7.718 June 19, 1854. Experiments of deflections. Deflecting magnet A. 67. Deflected magnet I. 7. Distance 1.3 feet. Magnet. North pole. Circle reads. Mean. 2u. Temp. w. w. 298° 54' 53'.5 42°.0 (I E. 53 329 47 46 46.5 30° 53'.0 42.2 E. E. 329 20 19.5 43.2 li W. 19 298 30 29 29.5 30 50.0 42.0 Means 30 51.5 42.4 Experiments of deflection. Distance 0.9 feet. Magnet. North pole. Circle reads. Mean. 2u. Temp. E. W. 259° 19' 18'.5 42°.2 N E. 18 365 31 29 30.0 • 106° ll'.S 42.0 W. E. 369 39 38.5 43.2 tt W. 38 263 09 07 08.0 106 30.5 41.8 Means 106 21.0 42.3 AT VAN RENSSELAER HARBOR. 57 June 24, 1854. Experiments of deflections. Deflecting magnet A. 67. Deflected magnet I. 7. Distance 0.9 feet. Magnet. North pole. Circle reads. Means. 2 u. Temp. w. E. W. E. E. W. 264° 10' 09 369 42 41 365 00 364 59 259 50 49 09'.5 41.5 59.5 49.5 105° 32'.0 105 10.0 Means 105 21.0 38°.0 38.0 38.0 38.0 38.0 Experiments of deflection. Distance 1.3 feet. Magnet. North pole. Circle reads. Means. 2u. Temp. E. W. W. E. E. W. 298° 37' 36 329 21 21 330 13 12 299 42 41 36'. 5 21.0 12.5 41.5 30° 44'.5 30 31.0 Means 30 37.7 38°.5 38.6 40.3 40.0 39.4 June 24, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 264. No. Time by chronometer 264. Time of 40 double vibrations. 1 2 3 4 5 6 7 8 9 10 11 4h 21m 34s. 3 49.6 22 05.2 20.7 36.3 51.8 23 07.3 22.8 38.4 53.8 24 09.1 41 42 43 44 45 46 47 48 49 50 51 4h 31ra 538.3 32 08,8 24.2 39.6 55.0 10.4 26.3 41.8 57.2 12.5 28.0 33 34 10m 19s. 0 19.2 19.0 18.9 18.7 18.6 19.0 19.0 18.8 18.7 18.9 10 18.89 Arcs 6° 16'. and 3 20 Temp. 41°.2. Time of 2 vibrations 15*. 4 7 2. The chronometer nearly shows Greenwich mean time, and its daily rate is less than 08.5 (gaining). 58 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY June 24, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 264. No. Time by chronometer 264. Time of 40 double vibrations. 1 4h 21m41".8 41 4h 31m598.0 10m 17s. 2 2 57.1 42 32 14.3 17.2 3 22 12.6 43 29.2 16.6 4 28.2 44 44.4 16.2 5 43.4 45 59.5 16.1 6 59.0 46 33 14.9 15.9 7 23 14.3 47 30.3 16.0 8 29.8 48 45.8 16.0 9 45.2 49 34 01.0 15.8 10 24 00.8 50 16.3 15.5 11 16.2 51 31.6 15.4 • 10 16.17 Arcs and temp, as before. Time of 2 vibrations 15 ".404. June 24, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 264. No. Time by chronometer 264. Time of 40 double vibrations. 1 4h 40m318.l 41 4h 50m 468.0 10m 14s. 9 2 46.5 42 51 01.3 14.8 3 41 02.0 43 16.8 14.8 4 17.4 44 32.0 14.6 5 32.8 45 47.5 14.7 6 48.2 46 52 02.8 14.6 1 42 03.5 47 18.1 14.6 8 18.9 48 33.4 14.5 9 34.3 49 48.8 14.5 10 49.8 50 53 04.1 14.3 11 43 05.1 51 19.4 14.3 10 14.60 Arcs 5° 52'. Temp. 41°.2. Time of 2 vibrations 15". 365. and 3 20 June 24, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 264. No. Time by chronometer 264. Time of 46 double vibrations. 1 4h 40m38'.8 41 4h 50m53".8 10m 15s. 0 2 54.2 42 51 09.2 15.0 3 41 09.5 43 24.6 15.1 4 24.9 44 40.0 15.1 5 40.2 45 55.4 15.2 6 55.8 46 52 10.8 15.0 7 42 11.1 48 26.2 15.1 8 26.3 47 41.6 15.3 9 41.9 49 57.0 15.1 10 57.2 50 53 12.3 15.1 11 43 12.6 51 27.8 15.2 10 15.11 Arcs and temp, as before. Time of 2 vibrations 15s. 3 1 8. AT VAN RENSSELAER HARBOR. 59 June 24, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 264. No. Time by chronometer 264. Time of 40 double vibrations. 1 2 3 4 5 6 7 8 9 10 11 5" 03m 298.3 44.9 04 00.3 15.6 31.0 46.4 05 01.8 17.1 32.3 47.8 06 03.2 41 42 43 44 45 46 47 48 49 50 51 5h 15m445.5 59.5 14 15.1 30.4 45.9 15 01.3 16.8 32.2 47.7 16 02.9 18.2 10m 15.2 14.6 14.8 14.8 14.9 14.9 15.0 15.1 15.4 15.1 15.0 10 14.982 Arcs 6° 16'. Temp. 41°. 2. Time of 2 vibrations 15s. 375. and 3 28 June 24, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 264. No. Time by chronometer 264. Time of 40 double vibrations. 1 2 3 4 5 6 7 8 9 10 11 5h 03m37M 52.4 04 07.8 23.2 38.4' 53.8 05 09.3 24.5 40.0 55.0 06 10.8 41 42 43 44 45 46 47 48 49 50 51 5h 13m52".0 14 07.6 23.0 38.3 53.8 15 09.1 24.5 39.9 55.2 16 10.6 26.0 101? 14.9 15.2 15.2 15.1 15.4 15.3 15.2 15.4 15.2 15.6 15.2 10 15.24 Arcs and temp, as before. Time of 2 vibrations 15s. 381. June 24, 1854. Experiments of vibrations. (Left to right.) No. Time by chronometer 264. No. Time by chronometer 264. Time of 40 double vibrations. 1 2 3 4 5 6 7 8 9 10 11 5h 18m388.3 54.0 19 09.3 24.9 40.3 55.7 20 11.2 26.7 42.2 57.5 21 12.9 41 42 43 44 45 46 47 48 49 50 51 5h 28m549.8 29 10.1 25.3 40.8 56.2 30 11.6 27.0 42.4 57.8 31 13.1 28.7 10m16'.5 16.1 16.0 15.9 15.9 15.9 15.8 15.7 15.6 15.6 15.8 10 15.89 Arcs 6° 48'. Temp. 41°.2. Time of 2 vibrations 15s. 397. 3 20 60 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY June 24, 1854. Experiments of vibrations. (Right to left.) No. Time by chronometer 264. No. Time by chronometer 264. Time of 40 doable vibrations. 1 5h 18m 46". 2 41 5h 29™ 02". 7 10m 168. 5 2 19 01.9 42 18.0 16.1 3 17.2 43 33.6 16.4 4 32.8 44 49.0 16.2 5 48.2 45 30 04.2 16.0 6 20 03.6 46 19.7 16.1 7 19.0 47 35.0 16.0 8 34.3 48 50.4 16.1 9 49.7 49 31 05.8 16.1 10 21 05.1 50 . 21.5 16.4 11 20.6 51 36.8 16.2 10 16.19 Arcs and temp, as before. Time of 2 vibrations 15s. 405. RECAPITULATION OF RESULTS, JUNE 24, 1854. Set No. 1. Time of 2 vibrations .... 158.472 Temp. 41°. 2 15.404 " 41.2 Set No. 2. " " . 15.365 " 41.2 15.378 " 41.2 Set No: 3. " " . 15.375 " 41.2 15.381 " 41.2 Set No. 4. . 15.397 " 41.2 15.405 ' " 41.2 Mean 15.397 41.2 Time of 1 vibration . . . 7.699 June 24, 1854. Experiments of deflections. Deflecting magnet A. 67. Deflected magnet I. 7. Distance .1.3 feet. Magnet. North pole. Circle reads. Means. 2 u. Temp. w. w. 300° 17' 15 le'.o 44°.2 « E. 330 29 27 28.0 30° 12'.0 43.0 E. E. 330 41 40 40.5 42.2 n W. 300 04 03 03.5 30 37.0 42.4 Means 30 24.5 42.9 Experiments of deflections. Distance 0. 9 feet. Magnet. North pole. Circle reads. Means. 2u. Temp. E. W. 261° 24' 23'.0 41.4 (1 E. 22 367 31 30 30.5 106° 07'.5 41.0 W. E. 373 07 05 06.0 42.4 ft W. 264 02 01 01.5 109 04.5 41.7 Means 107 36.0 41.6 AT VAN RENSSELAER HARBOR. 61 The detail record of the observations of deflections and vibrations at Van Rensselaer Harbor, in May, 1855, and of the vibrations at Hakluyt Island, and near Cape York, in June and July, 1855, could not be found; the results, how- ever, are preserved in Appendix No. XV. of the Narrative (vol. II.), and are here- with subjoined. SYNOPSIS OF RESULTS OF VIBRATIONS AND DEFLECTIONS, OBSERVED AT VAN RENSSELAER HARBOK DURING THE YEARS 1854 AND '55. Date. Temp.'s Time of Mean Corresponding Angle of Distance observed. 1 vibration. adopted. temp. deflection. in feet. T. t,. u. r. 1854. January 1 7 50°.0 7s. 705 ' ' 18 68.0 7.748 18 68.0 7.761 31 February 13 21 72.1 60.5 79.0 7.780 79.749 63°.0 15° 23'.3 39 20.0 1.3 0.975 21 79.0 7.782 ' . 21 55.0 7.755 21 55.0 7.758 27 57.5 15 24.8 1.3 June 7 33.0 7.644 7 33.0 7.644 7 33.0 7.657 7 33.0 7.656 7 7 36.0 34.9 7.678 34.0 53 58.7 15 38.5 0.9 1.3 7 35.0 7.702 7 35.0 7.706 7 35.0 7.705 7 35.0 7.704 - June 8 35.0 7.755 • 8 35.0 7.754 8 35.2 7.752 8 35.2 7.749 8 36.9 15 41.0 1.3 8 8 36.9 37.1 7.712 35.0 54 24.0 54 13.7 0.9 0.9 8 36.1 15 40.0 1.3 8 35.0 7.685 8 35.0 7.697 8 35.0 7.653 8 35.0 7.653 June 1 9 41.1 53 24.5 0.9 19 42.1 15 21.3 1.3 19 43.0 7.730 19 43.0 7.731 19 43.0 7.721 " 19 19 43.0 42.4 7.718 7.727 7.718 42.7 19 42.4 7.715 ' 19 42.4 7.702 19 42.4 7.702 19 42.4 15 25.7 1.3 19 42.3 53 10.5 0.9 62 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY. Date. Temp. 's observed. Time of 1 vibration. Mean adopted. Corresponding temp. Angle of deflecilon. Distance in feet. T. «, u. r. 1854. June 24 38°.0 52° 40'.5 0.9 24 39.4 15 18.8 1.3 24 41.2 7.736 24 41.2 7.702 24 41.2 7.683 24 24 41.2 41.2 7.689 7.688 7.699 41°.2 24 41.2 7.690 24 41.2 7.698 24 41.2 7.702 24 42.9 15 12.3 1.3 24 41.6 53 48.0 0.9 1855. May 16 17.0 7.448 16 19.3 7.416 16 16 17.0 17.0 > 7.405 19.3 14 37.1 50 50.7 1.3 0.9 16 22.0 7.384 16 19.0 7.371 - May 17 " 17 23.0 23.0 7.394 7.388 1 7.391 23.0 17 23.0 49 59.8 0.9 " 17 23.0 14 32.6 1.3 May 18 18 15.0 15.0 7.383 7.385 1 7.384 15.0 " 18 27.0 14 23.2 1.3 " 18 27.0 48 00.8 0.9 May 19 28.0 7.407 i 19 28.5 7.413 i i - 7.405 28.2 19 28.0 7.396 \ 19 27.0 49 00.7 0.9 19 27.0 14 36.7 1.3 ABSTRACT OF OBSERVATIONS OF VIBRATIONS AT HAKLUYT ISLAND. Approx. lat. 77° 23'. 1855. June 21. 33°.3 " 21. 33.3 " 21. 33.8 Approx. long. 72° 30' W. of Gr. 7s. 020 ) 7.026 > 7s. 026 7.033 ) 33°.5 ABSTRACT OF OBSERVATIONS OF VIBRATIONS AT A STATION IN LAT. 76° 03' AND LONG. 68° 00' W. OF GR., ON THE COAST BETWEEN PARKER SNOW'S POINT AND CAPE YORK. 1855. July 19. 40°.0 6".475~ " 19. 41.5 6.489 " 19. 41.2 6.544 " 19. 39.5 6.474 68.495 40°.5 DETERMINATION OF THE MOMENT OF INERTIA OF MAGNET A. 67. (With stirrup and mirror attached.) No determination of the moment of inertia of magnet A. 67 having been made by the expedition, it became necessary to determine the same afterwards. The following observations for this purpose were made by myself at the Coast Survey Office, Washington, D. C. MOMENT OP INERTIA OF MAGNET A. 67. 63 After adjusting the instrument and suspending A. 67, the following experiments of vibrations were made : — March 18, 1858. Mean time chronometer Kessels 1285. No. of Mean local time by 20 vibrations. No of Time by chronometer 18 vibrations. vibrations. chronometer 1285. vibrations. 1285. 0 9h 31m 10s. 7 ] m 21s 7 0 10h 28m 51". 3 lm 13s 2 20 32 32.4 91 ft 18 30 04.5 13 5 40 60 33 54.0 35 15.1 21.1 01 4. 36 54 31 18.0 32 31.0 13.0 13 8 80 100 36 36.5 37 58.0 , 21.5 72 90 33 44.8 34 57.9 13.1 Mean 1 21.47 Mean 1 13.32 Temp. 71°. 8. (Rate of chronometer too small Arc 234dand 328d Temp. 71°.0. to affect the result.) 1 vibration = 4s. 07 3. 242 318 1 vibration = 4 8.073 The mirror was below the magnet in these two sets; in the following four sets it was above. Magnet suspended with inertia ring Z, of the following dimensions: Outer diameter 2.322 inches; inner diameter 1.837 inches; thickness 0.188 inches at 69°; weight 648.937 grains: hence £i = i (r2 + rfi w = 4.936 (in feet and grains), ^jr, = 0.69338. Vibrations with ring. No. of vibrations. Time by chronometer 1285. 20 vibrations. No. of vibrations. Time by chronometer 1285. 20 vibrations. 0 20 40 60 80 100 12h 34m06s.O 36 32.2 38 58.8 41 24.1 43 49.6 46 15.4 2m 26". 2 26.6 25.3 25.5 25.8 0 20 40 60 80 100 12h48m13».6 50 39.5 53 05.3 55 31.5 58 00.4 13 00 26.6 2m 25". 9 25.8 26.2 28.91 26.2 2 25.88 2 26.02 Arc 190d— 360d Temp. 75°. 228 —321 1 vibration 7s. 294. Arc229d— 321d 239 —301 1 vibration=78.301 Vibrations without ring. No. of vibrations. Time by chronometer 1285. 20 vibrations. No. of vibrations. Time by chronometer 1285. 20 vibrations. 0 20 40 60 80 100 lh 17m29».9 18 51.2 20 12.5 21 34.0 22 55.1 24 17.0 lm 21". 3 21.3 21.5 21.1 21.9 0 20 40 60 80 100 lh 26™ 50s. 7 28 12.1 29 33.0 30 54.5 32 15.9 33 37.0 Im21".4 20.9 21.5 21.4 21.1 1 21.42 1 21.26 Arc 298d — 230d Temp. 76°. 1 vibration 4 '.071. 1 vibration = 4 ". 063. 1 Omitted, disturbed by a current of air. 64 MOMENT OP INERTIA OP MAGNET A. 61. Observations for torsion. Torsion circle. Scale readings. Mean. Biff. 74° 248—304 164 361—234 344 11—428 74 190—370 For torsion with r 276 297 220 280 ing use . . . 21d 77 60 31' = 39d for 90° 42 March 19, 1858. Vibrations without ring. (Mirror above.) No. of vibrations. Time by chronometer 1285. 20 vibrations. 0 20 40 60 80 100 gh 23m31».9 24 53.1 26 14.3 27 35.5 28 56.9 30 18.0 Im21'.2 21.2 21.2 21.4 21.1 Temp. 75°. 1 vibration = 4 8. 061. 1 21.22 Vibrations with ring. No. of vibrations. Time by chronometer 1285. 20 vibrations. 0 20 40 60 80 9h 50m 17s. 0 52 43.3 55 09.7 57 35.5 60 01.1 2m26".3 26.4 25.8 25.6 1 vibration = 7s. 301. 2 26.02 RECAPITULATION OF RESULTS. March 18, 1858. 1 vibration, without ring . ii with ci without (i March 19, 1858. " " with Mean by combination 4s. 073 4.073 4.071 4.063 4.061 — Temp. 71°.8 71.0 7s. 294 75.0 7.301 75.0 76.0 76.0 75.0 7,301 75.0 T=4.069 at 74°.0 T,=7.299 at 75°.0 The moment of inertia of the magnet (with appendages) K becomes for the temp. 69° (and corrected for torsion) K= K, r2 = 2.220 and lg K= 0.34631. Using 0.0000068 for the coefficient of dilatation for 1° Fahr., the above lg K for different temperatures becomes : For 62°, lg K= 0.34628 and lgn*K= 1.34058 " 32, " 0.34609 = 1.34039 (CnAS. A. S.) MAGNETIC INTENSITY, FERN ROCK OBSERVATORY. 65 The value of the induction coefficient p _ rVj8 sin. ul — r^r6 sin. u rf sin. H! — r' sin. u may be put in the following convenient form — off — p3 •, sin.u1 r 1 = — r =- where a = — : ana £ = — . a — f sin. u i\ Wefind:June 7,1854 . . P = — 0.007 " 8, " —0.003 " 8, " —0.006 " 19, " . +0.009 " 19, " . . . — 0.003 " 24, " —0.001 " 24, " . r+ 0.033 May 16, 1855 . I +0.035 " 17, " [ +0.039 j " 18, " . —0.011 " 19, " —0.011 If we take the indiscriminate mean of the above values we find P = + 0.007, and if we reject the three values marked by brackets, P= — 0.004; the latter value is probably nearer the truth than the first one, but both are so small that they may be neglected in the computation of the intensity. In the absence of observations, the temperature coeiBcient for the magnetic moment or q may be assumed = 0.0003, a value found for other magnets of the same magnetic moment and size; with but three exceptions, the temperature cor- rections are small. After correcting for difference of temperature, the following results for magnetic moment m and horizontal intensity X have been computed by the formula} Wl i 9 i -v 71" K — = 2 r3 sin. u and m X== -— . ^. it Jt 66 MAGNETIC INTENSITY, FERN ROCK OBSERVATORY. m TABLE OF RESULTS OF log. — , log. m X, OF m THE MAGNETIC MOMENT OF MAGNET A. 67, AND OF THE HORIZONTAL INTENSITY X, AT VAN RENSSELAER HARBOK. Date. ":§• Ig. m X. in. X. 1854. Jan. 31 9.46463 9.56091 0.326 1.117 Feb. 13 9.46795 9.56243 0.327 1.115 " 27 9.46532 9.56282 0.327 1.119 June 7 9.46954 9.56964 0.330 1.122 7 9.47155 9.56980 0.331 1.120 8 9.47268 9.56583 0.330 1.113 8 9.47184 9.56583 0.330 1.114 8 9.47091 9.56581 0.330 1.115 8 9.47223 9.56593 0.330 1.114 19 9.46636 9.56570 0.328 1.121 19 9.46371 9.56556 0.327 1.124 19 9.46574 9.56552 0.328 1.122 19 9.46504 9.56553 9.328 1.123 24 9.46218 9.56801 0.327 1.130 24 9.46256 9.56782 0.328 1.129 24 9.45956 9.56737 0.326 1.133 24 9.46855 9.56754 0.330 1.121 1855. May 16 9.44285 9.60156 0.332 1.200 16 9.45125 9.60156 0.336 1.189 17 9.44593 9.60293 0.334 1.198 17 9.44065 9.60293 0.332 1.206 18 9.43607 9.60219 0.331 1.210 18 9.43286 9.60219 0.329 1.215 19 9.43956 9.60148 0.332 1.205 19 9.44266 9.60148 0.332 1.200 Mean value of m = 0.330 at I = 36°.' RECAPITULATION OF VALUES OF X. January 31,1854 A'= 1.117 February 20, " 1.117 Juno 15, " 1.121 May 18, 1855 1.203 Mean corresponding to June, 1854 . . . 1.139 Taking the above value 1.139 for the mean horizontal force during the whole period, and multiplying it by sec. 84° 45'.8, the total force at Van Rensselaer Harbor during the same period becomes