Chapter XXX: Appendix (3)

+---------------------+--------+--------------------+------------+
| | | Time of Vibration | |
| | |as a Dipping-Needle.| Intensity |
| | |---------+----------+-----+------+
| |Observed|At each | At | | |
| Station. | Dip |Station. | Plymouth.| 1. | 2. |
+---------------------+--------+---------+----------+-----+------+
| | deg ' | s. | s. | | |
| {| | | | | |
| Pernambuco {| 13 12,9| 566,8 | 462,2 |0,665|0,914 |
| {| | | | | |
| {| | | | | |
| | | | | | |
| {| | | | | |
| Port Praya {| 45 46,5| 503,9 | 462,2 |0,841|1,157 |
| {| | | | | |
| {| | | | | |
| | | | | | |
| Terceira {| 68 06 | 449,1 | 462,2 |1,059|1,457 |
| {| | | | | |
| | | | | | |
| {| | | | | |
| Plymouth {| 69 17,5| 462,2 | 462,2 |1,000|1,375 |
| {| | | | | |
+---------------------+--------+---------+----------+-----+------+

Observers:--F. Captain Fitz-Roy. Ss. Mr. J.L. Stokes. Kg. Capt. King.
S. Lieut. Sulivan. St. Mr. P.B. Stewart. K. Mr. P.G. King.

* * * * *

{515}

3. _Captain King's Observations of Dip and Intensity._

Captain King, having hitherto made known his observations with the same cylinder in the years 1826 to 1830 only by communicating them to M. Hansteen, from whom he received the apparatus, has now given permission to Captain Fitz-Roy to publish them with his own. I have already noticed the great loss of magnetism which took place in this cylinder during Captain King's voyage, and the care with which that officer availed himself of every opportunity of ascertaining, by direct observation, the proportion of the loss sustained in separate portions of the voyage. There are twelve stations of observation on the east and west coasts of South America, besides three stations in ports of the Atlantic on the outward voyage. By the practice of repeating observations at the same station at distant intervals, the South American stations are so linked together and connected, that by adopting a method similar to that used in determining longitudes by means of chronometers, we may compute the intensity at all the South American stations referred to and dependent on the force at Rio de Janeiro; regarding Rio in the same light as a first meridian is considered in determinations of longitude. We may then make Rio the means of connecting the whole series with Europe; for which it is remarkably well suited, the intensity there having been determined, independently of Captain King, by four observers of different nations, whose results are extremely accordant.

The dip observations of Captain King were communicated, in occasional correspondence during the voyage, to M. Hansteen, who computed them by Mayer's formula, and arranged them in a table, of which a copy was given by Captain King to Captain Fitz-Roy, and is printed in the next page. At some of the stations Captain Fitz-Roy also observed the dip in the subsequent voyage, and, as will be seen, the results of the two observers sometimes differ considerably. This may have been caused, either by instrumental or other error of observation, or by actual differences of dip existing in different localities at the same station.

* * * * *

{516}

DIPS, _observed by_ Capt. P. P. King, 1826 to 1831.

+------------------+-------+---------------------+---------------------+
| | |Marked end a N. Pole.|Marked end a S. Pole.|
| | |----------+----------+----------+----------+
| Station. |Needle.| a | a' | a" | a"' |
+------------------+-------+----------+----------+----------+----------+
| | | deg ' | deg ' | deg ' | deg ' |
| Rio de Janeiro {| 1 | 15 58,5 | 13 02,4 | 15 05,7 | 13 18,0 |
| {| 2 | 14 39,4 | 12 30,4 | 14 49,0 | 13 07,3 |
| | | | | | |
| {| 1 | 22 54,1 | 24 04,7 | 21 55,6 | 22 46,0 |
| Sta. Catharina {| 2 | 23 22,8 | 20 32,3 | 23 34,2 | 21 00,7 |
| {| 3 | 21 17,8 | 21 08,5 | 23 26,2 | 22 57,2 |
| | | | | | |
| {| 1 | 36 48,4 | 37 49,3 | 35 25,4 | 37 26,9 |
| Monte Video {| 2 | 37 17,2 | 34 53,8 | 37 17,1 | 34 37,4 |
| {| 3 | 36 36,1 | 35 10,3 | 37 12,4 | 36 13,2 |
| | | | | | |
| {| 1 | 64 41,7 | 52 42,6 | 65 51,2 | 54 54,0 |
| Port Famine {| 2 | 60 41,9 | 59 32,2 | 60 32,1 | 59 33,6 |
| {| 3 | 60 03,9 | 58 43,4 | 60 35,5 | 59 37,5 |
| | | | | | |
| {| 1 | 41 09,9 | 30 50,9 | 41 04,6 | 31 32,6 |
| Gorriti {| 2 | 36 29,2 | 33 26,4 | 35 17,1 | 34 02,7 |
| {| 3 | 34 52,3 | 34 18,5 | 36 06,9 | 35 01,3 |
| | | | | | |
| Sea Bear Bay | 1 | 58 26,5 | 47 53,8 | 60 34,8 | 47 53,4 |
| | | | | | |
| {| 1 | 65 24,7 | 54 23,8 | 65 47,7 | 54 43,6 |
| St. Martin Cove {| 2 | 60 25,6 | 59 28,3 | 59 49,9 | 58 48,6 |
| {| 3 | 59 48,9 | 58 40,7 | 60 43,4 | 59 53,3 |
| | | | | | |
| {| 1 | 54 23,9 | 45 38,3 | 56 19,2 | 45 11,1 |
| Chiloe {| 2 | 50 24,0 | 49 12,9 | 50 28,4 | 48 29,6 |
| {| 3 | 49 43,9 | 48 48,3 | 51 24,5 | 50 02,2 |
| | | | | | |
| {| 1 | 43 04,5 | 33 59,9 | 44 38,8 | 34 54,6 |
| Valparaiso {| 2 | 40 48,2 | 40 49,7 | 40 53,7 | 41 09,7 |
| {| 3 | 40 54,9 | 40 45,4 | 40 49,8 | 41 16,7 |
| | | | | | |
| {| 1 | 50 22,7 | 39 16,0 | 51 08,2 | 40 03,2 |
| Juan Fernandez {| 2 | 44 19,3 | 45 57,6 | 43 45,8 | 46 13,7 |
| {| 3 | 45 50,4 | 45 07,9 | 44 34,8 | 43 25,7 |
| | | | | | |
| Talcahuano | -- | -- | -- | -- | -- |
+------------------+-------+----------+----------+----------+----------+

+------------------+---------------------+-------------------------+
| | | |
| | | |
| Station. | Dip deduced. | Remarks. |
+------------------+---------------------+-------------------------+
| | deg ' deg ' | |
| Rio de Janeiro {| 14 16,2 } 14 00,1 S.| |
| {| 13 44,1 } | |
| | | |
| {| 22 49,6 } | |
| Sta. Catharina {| 22 03,6 } 22 12,4 S.| |
| {| 21 44,0 } | |
| | | |
| {| 37 00,7 } | |
| Monte Video {| 35 59,3 } 36 28,4 S.| |
| {| 36 25,3 } | |
| | | |
| {| 59 44,9 } | |
| Port Famine {| 60 04,5 } 59 52,6 S.| |
| {| 59 48,5 } | |
| | | |
| {| 35 38,3 } | |
| Gorriti {| 34 43,8 } 35 05,9 S.| |
| {| 34 55,6 } | |
| | | |
| Sea Bear Bay | 53 13,5 53 13,5 S.| |
| | | |
| {| 59 46,4 } | |
| St. Martin Cove {| 59 38,4 } 59 43,8 S.| |
| {| 59 46,6 } | |
| | | |
| {| 49 59,4 } | |
| Chiloe {| 49 38,7 } 49 52,6 S.| |
| {| 49 59,7 } | |
| | | |
| {| 38 40,1 } | |
| Valparaiso {| 40 55,4 } 40 10,7 S.| |
| {| 40 56,7 } | |
| | | |
| {| 44 40,5 } | |
| Juan Fernandez {| 45 04,6 } 53 13,5 S.| |
| {| 44 44,7 } | |
| | | |
| Talcahuano | -- 45 10,0 S.|The particulars of this |
| | |observation are wanting. |
+------------------+---------------------+-------------------------+

{517}

The following TABLE contains Captain KING'S Observations of Intensity, with the times of vibration corrected for the arc and reduced to a standard temperature of 60deg.

MAGNETIC INTENSITY, _observed by_ Capt. P. P. King _between 1826 and 1831._

----------------+------------+------+------+-----------+-----------------
| | | | Corrected |
Station. | Date. | Time.|Therm.| Time. |Particular place.
----------------+------------+------+------+-----------+-----------------
| | s. | deg | |
Greenwich {|1826 Mar. 22|734,45| 55,0 | 733,97 }|Observatory.
{|1831 Jan. 24|775,80| 41,6 | 776,01 }|
| | | | |
Madeira |1826 May 31|628,68| 66,0 | 627,79 |Consul's Garden.
| | | | |
Teneriffe | -- June 12|607,96| 75,0 | 606,73 |Fort St. Pedro.
| | | | |
Port Praya {| -- -- 22|559,53| 81,5 |} 557,08 {|Landing Place,
{| -- -- 24|557,58| 85,0 |} {|Quail Island.
| | | | |
{| -- Aug. 29|546,36| 77,0 | 545,16 }|
{|1827 Sept.12|552,06| 75,5 | }|
Rio de Janeiro {| -- -- 15|552,95| 80,0 |} }|Rat Island.
{| -- -- 15|553,73| 83,0 |} 551,70 }|
{| -- -- 15|553,48| 85,0 |} }|
{|1828 Dec. 21|562,55| 84,0 | 561,05 }|
| | | | |
Sta Catharina |1827 Nov. 3|554,42| 67,5 | 553,58 |Anhatomirim.
| | | | |
{|1826 Oct. 29|550,68| 63,0 |} 549,44 }|
Gorriti {| -- Nov. 6|549,63| 66,0 |} }|The Well.
{|1829 Jan. 10|564,12| 80,0 | 562,78 }|
| | | | |
{|1827 Dec. 18|555,12| 78,3 | 553,87 }|South point near
Monte Video {|1828 Oct. 8|562,00| 72,5 | 560,95 }|the sea.
{|1830 June 1|565,41| 59,0 | 564,89 }|
| | | | |
Port Sta Elena |1826 Dec. 4|557,26| 68,0 | 556,42 |Landing-place.
| | | | |
Sea Bear Bay |1829 Mar. 20|577,36| 70,0 | 576,37 |Landing-place.
| | | | |
{|1827 Jan. 15|584,88| 56,0 |} |
St. Martin Cove{| -- -- 15|583,48| 58,0 |} 584,29 }|Head of the
{| -- -- 22|585,82| 55,0 |} }|Cove.
{| -- Mar. 27|585,82| 64,0 | 585,08 }|
| | | | |
{|1828 Jan. 28|589,75| 55,0 | 589,36 }|
{| -- May 8|596,49| 43,8 | 596,54 }|
Port Famine {| -- June 18|595,86| 32,7 |} 595,81 }|Observatory.
{| -- July 30|594,85| 36,2 |} }|
{|1830 Apr. 30|598,95| 45,0 | 598,97 }|
| | | | |
Chiloe {|1829 Sept. 1|565,40| 54,0 |} 565,23 |San Carlos.
{| -- Dec. 15|565,69| 53,0 |} |
| | | | |
Juan Fernandez |1830 Feb. 19|552,77| 70,0 | 551,83 |Landing-place.
| | | | |
Talcahuano {|1829 Dec. 18|556,42| 67,0 | 555,59 }|Fort Galvez.
{|1830 May 12|557,18| 60,5 | 557,18 }|
| | | | |
{|1829 Aug. 4|549,10| 59,0 | 548,59 }|
Valparaiso {|1830 Jan. 11|551,77| 77,0 |} 551,60 }|Almendral.
{| -- Feb. 1|553,50| 68,5 |} }|
----------------+------------+------+------+-----------+-----------------

{518}

At Rio de Janeiro, which was the first station observed at in South America, the cylinder was vibrated in August 1826, September 1827, and December 1828; in the intervals between these dates are comprised the greater part of the observations on the east side of South America. There is no direct observation at Rio subsequently to December 1828; but we are enabled to supply the time of vibration, which would have been observed had the cylinder been employed at Rio on June 1, 1830, in the following manner. We have seen that on the 15th September 1827 the time of vibration was observed at Rio; on the 18th December following it was observed at Monte Video. These observations give the intensity at Monte Video relatively to that at Rio, subject to whatever change of magnetism the cylinder may have undergone in the interval of three months. This comparison was repeated in the following year, on Captain King's return from Monte Video to Rio, the interval being nearly of the same duration, and the order of the experiment reversed, the passage being in this instance from Monte Video to Rio, it having been before from Rio to Monte Video. On the supposition of an uniform, or nearly uniform rate of change in the cylinder, the errors arising therefrom during the two passages would be of opposite kinds, and should compensate each other in a mean of the two comparisons. Calling the force at Rio unity, these comparisons give its value at Monte Video respectively as follows, namely,

September and December 1827 ... 1.197 }
October and December 1828 ... 1.207 } Mean 1.202.

On the 1st of June 1830, being then on his return from the west coast of South America, and on the eve of sailing for England, Captain King again observed the time of vibration of the cylinder at Monte Video; whence, through the preceding comparison, we obtain the time of vibration at Rio, which should belong to the same date. We have thus a fourth date at Rio, which, added to those enumerated above, will include the whole of the South American stations; and we have only to distribute in each interval the loss of magnetism which the observations shew to have taken place from one date to the next, in the manner which may appear most suitable. There is no very obvious indication that the loss was other than gradual; and by considering it uniform in each separate {519} interval, the results are found extremely accordant at several other stations at which observations were repeated at distant intervals.

In the first of the subjoined tables are given the times of vibration at Rio at the four periods referred to; and the corresponding times as a dipping needle. In its three last columns are shewn,--the number of days comprised in each interval,--the increase in the time of vibration owing to the loss of magnetism,--and the resulting daily correction, on the supposition in each case of the loss having been uniform in the interval during which it occurred.

The second table contains the corrected times of horizontal vibration at each of the South American stations, at the dates respectively inserted,--the corresponding times as a dipping needle,--the times of vibration as a dipping needle at Rio de Janeiro at the same dates, derived from the observations in the first table,--and the resulting intensity at each station relatively to unity at Rio. Thus far the results are derived from Captain King's observations, unmixed with those of any other observer: but in order to bring Captain King's series into connexion with the general body of results of other observers, the values of his intensities are expressed in the final column in terms of the scale in common use, in which the force at Paris = 1,348, and at Rio de Janeiro 0,884; the latter being the mean of four independent determinations by the following observers, namely,

1817 and 1820 Freycinet 0,890 }
1827 Luetke 0,886 } 0,884
1830 Erman 0,879 }
1836 Fitz-Roy 0,878 }

Port St. Elena is not included in this table, as no dip was observed there, and the total intensity consequently cannot be computed. The three stations, Madeira, Teneriffe, and Port Praya, at which the cylinder was vibrated in the outward voyage, are also without dips observed by Captain King. The deficiency at Port Praya has been supplied from Captain Fitz-Roy's observations and my own, both having been made at the same place at which Captain King's intensity was observed,--Captain Fitz-Roy's at a later, and mine at an earlier date. At Madeira also the dip has been supplied from my observations, which were made in the British consul's garden at Funchal, where Captain King's cylinder was vibrated. I have {520} deducted, from my determination of the dip, 12' for the probable change between 1822 and 1826. At Teneriffe the dip has been frequently observed; but the values assigned by different observers vary so much as to indicate a more than usual frequency of local disturbance, which might also be expected from the geological character of that island. It would be unsafe therefore to employ any dip for that station but one which was certainly obtained at the same spot at which the horizontal intensity was observed.

The dates of the observations at these three stations fall between the observations at Greenwich in March 1826, and those at Rio de Janeiro in August of the same year. Having the intensity at Greenwich = 1,372 and at Rio = 0,884, and the dip at Greenwich 69deg 52', and at Rio 14deg 00, we have the time of vibration of Captain King's cylinder as a dipping needle at Rio at the respective dates as follows, namely,

March 1826 536,2.
August 1826 537,0.

It appears therefore that but a very slight change took place in the magnetism of the cylinder during the outward voyage, and we may take 536,6 as the time of vibration at Rio, corresponding to the dates of the intermediate observations; and this is done in the table for Madeira and Port Praya. {521}

TABLE I.

------------------+------------------------+---------+-----+---------
| Time of Vibration. | | |
|-----------+------------+ | |
Rio de Janeiro. |Horizontal.|As a Dipping|Interval.|Loss.|Per Diem.
| | Needle. | | |
------------------+-----------+------------+---------+-----+---------
| s. | s. | Days. | s. |
August 29, 1826 | 545,2 | 537,0 |} 382 | 6,5 | .017
September 15, 1827| 551,7 | 543,5 |} | |
December 21, 1828 | 561,1 | 552,7 | 462 | 9,2 | .020
June 1, 1830 | 563,8 | 555,4 | 527 | 2,7 | .005
------------------+-----------+------------+---------+-----+---------

TABLE II.

---------------+-------------+------------------------+------------------
| | Time of Vibration. | Intensity.
| |------------------------+-----------+------
| | At the Station.|At Rio.| |
| |--------+-------+-------+ |
| | | As a | As a | |
| | |Dipping|Dipping| |Rio=
Station. | Date. |Horizon.|Needle.|Needle.| Rio=1,000.|0,884.
---------------+-------------+--------+-------+-------+-----------+------
| | s. | s. | s. | |
Madeira |1826 May 31| 627,79 | 430,1 | 536,6 |1,556 |1,377
| | | | | |
Port Praya {|1826 June 22|}557,08 | 465,4 | 536,6 |1,330 |1,177
{| and 24|} | | | |
| | | | | |
Sta Catharina |1827 Nov. 3| 553,58 | 532,7 | 544,5 |1,045 |0,920
| | | | | |
Gorriti {|1826 Oct. 29|}549,44 | 497,0 | 538,1 |1,172} |
-- {| and Nov. 6|} | | | }1,175|1,041
-- |1829 Jan. 10| 562,78 | 509,0 | 552,8 |1,179} |
| | | | | |
Monte Video |1827 Dec. 18| 553,87 | 496,7 | 545,4 |1,206} |
-- |1828 Oct. 8| 560,95 | 503,0 | 551,3 |1,201}1,203|1,065
-- |1830 June 1| 564,89 | 506,6 | 555,4 |1,202} |
| | | | | |
Sea Bear Bay |1829 Mar. 20| 576,37 | 446,0 | 553,1 |1,538 |1,361
| | | | | |
St. Martin {|1827 Jan. 15|}584,29 | 414,9 | 539,4 |1,691} |
Cove {| and 22|} | | | }1,692|1,498
-- | -- Mar. 27| 585,08 | 415,4 | 540,6 |1,694} |
| | | | | |
Port Famine |1828 Jan. 28| 589,36 | 417,5 | 546,2 |1,712 |
-- | -- May 8| 596,54 | 422,6 | 548,2 |1,683} |
-- {| -- June 18|}595,81 | 422,1 | 549,3 |1,694}1,700|1,505
{| and July 30|} | | | } |
-- |1830 April 26| 598,97 | 424,3 | 555,1 |1,712} |
| | | | | |
Chiloe {|1829 Sept. 1|}565,23 | 453,7 | 554,2 |1,402 |1,321
{| and Dec. 15|} | | | |
Juan Fernandez |1830 Feb. 19| 551,83 | 464,7 | 554,8 |1,425 |1,262
| | | | | |
Talcahuano |1829 Dec. 18| 555,59 | 466,5 | 554,6 |1,413}1,412|1,250
-- |1830 May 12| 557,18 | 467,4 | 555,3 |1,412} |
| | | | | |
Valparaiso |1829 Aug. 4| 548,59 | 479,5 | 553,9 |1,334}1,329|1,176
-- {|1830 Jan. 11|}551,60 | 482,1 | 554,6 |1,324} |
{| and Feb. 1|} | | | |
---------------+-------------+--------+-------+-------+-----------+------

{522}

4.--The following Table exhibits the MAGNETIC OBSERVATIONS of Captains King and Fitz-Roy collected in one view.

---------------+---------+----------+----------+--------------+----------
| | | | |Intensity,
| | | | | Paris=
Stations. |Latitude.|Longitude.|Variation.| Dip. | 1,348.
---------------+---------+----------+----------+--------------+----------
| deg ' | deg ' | deg ' | deg ' |
Madeira | 32 38 N.| 16 56 W. | -- | | K. 1,377
| | | | |
Terceira | 38 39 N.| 27 13 W. | 24 18 W. | F. 68 06 N.| F. 1,457
| | | | |
| | | |{ -- | K. 1,177
Port Praya | 14 54 N.| 23 30 W. | 16 30 W. |{F. 46 20,2 N.| F. 1,154
| | | |{F. 45 46,5 N.| F. 1,157
| | | | |
Ascension | 7 56 S.| 14 24 W. | 13 30 W. | F. 1 39,2 N.| F. 0,873
| | | | |
St. Helena | 15 55 S.| 5 43 W. | 18 00 W. | F. 18 01,2 S.|{F. 0,822
| | | | |{F. 0,850
| | | | |
Falkland | 51 32 S.| 58 07 W. | 19 00 E. |{F. 53 30,4 S.| F. 1,349
Islands | | | |{F. 53 19,6 S.| F. 1,385
| | | | |
Pernambuco | 8 04 S.| 34 51 W. | 5 54 W. | F. 13 12,9 N.| F. 0,914
| | | | |
Bahia | 12 59 S.| 38 30 W. | 4 18 W. |{F. 4 55,8 N.|}F. 0,871
| | | |{F. 5 53,5 N.|}
| | | | |
Rio de Janeiro | 22 55 S.| 43 09 W. | 2 00 E. |{K. 14 00,1 S.|}F. 0,878
| | | |{F. 13 37,4 S.|}
| | | | |
Sta Catharina | 27 26 S.| 48 33 W. | -- | K. 22 12,4 S.| K. 0,920
| | | | |
Gorriti | 34 57 S.| 54 57 W. | -- | K. 35 05,9 S.| K. 1,041
| | | | |
Monte Video | 34 53 S.| 56 13 W. | 12 00 E. |{K. 36 28,4 S.| K. 1,065
| | | |{F. 34 51,2 S.| F. 1,055
| | | | |
Blanco Bay | 38 57 S.| 61 59 W. | 15 00 E. | F. 41 54,0 S.| F. 1,113
| | | | |
Port Desire | 47 45 S.| 65 55 W. | 20 12 E. | F. 52 43,5 S.| F. 1,359
| | | | |
Sea Bear Bay | 47 51 S.| 65 48 W. | -- | K. 53 13,5 S.| K. 1,361
| | | | |
R. Santa Cruz | 50 07 S.| 68 24 W. | 20 54 E. | F. 55 15,7 S.| F. 1,425
| | | | |
St. Martin Cove| 55 51 S.| 67 34 W. | -- | K. 59 43,8 S.| K. 1,498
| | | | |
Port Famine | 53 38 S.| 70 58 W. | 23 00 E. | K. 59 52,6 S.|{K. 1,505
| | | | |{F. 1,560
| | | | |
Port San Andres| 46 35 S.| 75 35 W. | 20 48 E. | F. 54 13,6 S.| --
| | | | |
Port Low | 43 48 S.| 74 02 W. | 19 48 E. | F. 51 20,1 S.| F. 1,326
| | | | |
Chiloe | 41 51 S.| 73 56 W. | 18 00 E. |{K. 49 52,6 S.| K. 1,321
| | | |{F. 48 58,9 S.| F. 1,304
| | | | |
Valdivia | 39 53 S.| 73 29 W. | 17 30 E. | F. 46 46,5 S.| F. 1,238
| | | | |
Concepcion | 36 42 S.| 73 10 W. | 16 48 E. |{K. 45 10,0 S.| K. 1,250
| | | |{F. 43 15,4 S.| F. 1,186
| | | | |
Valparaiso | 33 02 S.| 71 41 W. | 15 18 E. |{K. 40 10,7 S.|}K. 1,176
| | | |{F. 38 03,1 S.|}
| | | | |
Coquimbo | 29 59 S.| 71 26 W. | 14 24 E. | -- | F. 1,111
| | | | |
Callao | 12 04 S.| 74 14 W. | 10 00 E. | F. 7 02,8 S.|
| | | | |
Galapagos | 0 50 S.| 89 37 W. | 9 30 E. | F. 8 41,2 N.|
Islands | | | | |
| | | | |
Ditto | 0 15 S.| 90 31 W. | 9 30 E. | F. 9 28,6 N.| F. 1,069
| | | | |
Juan Fernandez | 33 38 S.| 78 53 W. | | K. 44 49,8 S.| K. 1,262
| | | | |
Otaheite | 17 29 S.|149 30 W. | 7 54 E. | F. 30 13,5 S.| F. 1,017
| | | | |
Cape of Good | 34 11 S.| 18 26 E. | 28 30 W. | F. 52 35,0 S.| F. 1,014
Hope | | | | |
| | | | |
Mauritius | 20 09 S.| 57 31 E. | 11 18 W. | F. 54 00,8 S.| F. 1,192
| | | | |
Keeling Islands| 12 05 S.| 96 55 E. | 1 12 W. | F. 38 33,1 S.|
| | | | |
New Zealand | 35 16 S.|174 00 E. | 14 00 E. | F. 59 32,0 S.| F. 1,591
| | | | |
King George | 35 02 S.|117 56 E. | 5 36 W. | F. 64 41,3 S.| F. 1,709
Sound | | | | |
| | | | |
Hobart Town | 42 53 S.|147 24 E. | 11 06 E. | F. 70 34,9 S.| F. 1,817
| | | | |
Sydney | 33 51 S.|151 17 E. | 10 24 E. | F. 62 49,4 S.| F. 1,685
---------------+---------+----------+----------+--------------+----------

{523}

GENERAL REMARKS.

1. _Variation._

Captain Fitz-Roy's observations are so well distributed over the southern hemisphere, that a good view of the changes which the variation is undergoing throughout its meridians may be obtained by comparing his determinations with those of earlier observers at the same stations. The following table has been formed for the purpose of exhibiting such a comparison at all those stations where materials for it exist; and I may here remark how much such comparisons are facilitated by the valuable collection of early observations contained in the Appendix to the Magnetismus der Erde.

CAPE OF GOOD HOPE. | VALPARAISO.
Observer. | Date.| Variation.| Observer. | Date.| Variation.
| | deg ' | | | deg '
Davis | 1605 | 0. 30 E. | Don G. Juan | 1744 | 12. 30 E.
Keeling | 1609 | 0. 12 W. | Vancouver | 1793 | 14. 49 E.
Leydecker | 1675 | 8. 28 W. | Luetke | 1827 | 15. 00 E.
Mathews | 1724 | 16. 22 W. | Fitz-Roy | 1835 | 15. 18 E.
La Caille | 1752 | 19. 0 W. |
Wales | 1772 | 20. 26 W. | CALLAO.
Wales | 1775 | 21. 14 W. | Ulloa | 1740 | 9. 02 E.
Bligh | 1788 | 23. 16 W. | Duperrey | 1823 | 9. 30 E.
Dentrecasteaux | 1792 | 24. 30 W. | Fitz-Roy | 1835 | 10. 36 E.
Freycinet | 1818 | 26. 31 W. |
Fitz-Roy | 1836 | 28. 30 W. | GALAPAGOS ISLANDS.
| Vancouver | 1794 | 8. 00 E.
ST. HELENA | B. Hall | 1821 | 8. 20 E.
Davis | 1610 | 7. 13 E. | Fitz-Roy | 1835 | 9. 30 E.
Halley | 1677 | 0. 40 E. |
Halley | 1691 | 1. 0 W. | OTAHEITE.
Mathews | 1724 | 7. 30 W. | Cook | 1769 | 4. 45 E.
Wales | 1775 | 12. 18 W. | Wales | 1773 | 5. 40 E.
Hunter | 1789 | 15. 30 W. | Bayley | 1774 | 5. 49 E.
Macdonald | 1796 | 15. 48 W. | Vancouver | 1794 | 6. 12 E.
Krusenstern | 1806 | 17. 18 W. | Duperrey | 1823 | 6. 40 E.
Fitz-Roy | 1836 | 18. 00 W. | Fitz-Roy | 1835 | 7. 34 E.
|
RIO DE JANEIRO. | BAY OF ISLANDS, N. ZEALAND.
Cook | 1768 | 7. 34 E. | Tasman | 1643 | 8. 40 E.
Hunter | 1787 | 6. 12 E. | Cook | 1769 | 11. 25 E.
Freycinet | 1820 | 2. 54 E. | Duperrey | 1824 | 13. 22 E.
Rumker | 1821 | 3. 21 E. | Fitz-Roy | 1835 | 14. 00 E.
Erman | 1830 | 2. 10 E. |
Fitz-Roy | 1836 | 2. 00 E. | SYDNEY.
| Cook | 1770 | 8. 00 E.
FALKLANDS ISLANDS. | Hunter | 1787 | 8. 30 E.
Freycinet | 1820 | 19. 26 E. | Flinders | 1803 | 8. 51 E.
Duperrey | 1822 | 19. 07 E. | Freycinet | 1819 | 9. 15 E.
Fitz-Roy | 1833 | 19. 00 E. | Duperrey | 1824 | 8. 56 E.
| Fitz-Roy | 1836 | 10. 24 E.
PORT FAMINE |
Wallis | 1766 | 22. 30 E. | VAN DIEMEN'S LAND.
Carteret | 1766 | 22. 22 E. | Tasman | 1642 | 3. 00 E.
Fitz-Roy | 1831 | 23. 00 E. | Bayley | 1777 | 7. 29 E.
| Bligh | 1778 | 8. 33 E.
CONCEPCION. | Fitz-Roy | 1836 | 11. 06 E.
La Perouse | 1786 | 15. 15 E. |
B. Hall | 1821 | 15. 30 E. | MAURITIUS.
Duperrey | 1823 | 16. 16 E. | Keeling | 1609 | 21. 0 W.
Fitz-Roy | 1835 | 16. 48 E. | Mathews | 1722 | 19. 4 W.
| Freycinet | 1818 | 12. 46 W.
| Duperrey | 1824 | 13. 46 W.
| Fitz-Roy | 1836 | 11. 18 W.

{524} We may derive from the facts in the above table the following general and easily remembered conclusion in regard to the changes of the variation in the southern hemisphere; namely, that taking for our point of departure the meridian of 65deg west in South America, we find that at all the stations east of that meridian to the Cape of Good Hope inclusive, the north pole of the needle has moved towards the west; and that all the stations west of the same meridian to Mauritius inclusive, the north pole of the needle has moved towards the east.

An almost equally simple generalization may be drawn in respect to the changes of situation of the lines of equal variation in the southern hemisphere: but here it must be supposed either that the reader is thoroughly familiar with the general arrangement of these lines, or that he has a map of them before him. He will find such a map of the variation lines in 1787 in the Fifth Report of the British Association; but any other map, corresponding to any epoch within the last hundred years, will equally serve the purpose. Referring to such a map, it will be seen that the lines of variation in the South Pacific, form a system of nearly concentric curves, of an oval, or pear-shaped form, the outside curves having a higher variation, which progressively diminishes to the centre. We may regard this system as comprehending the whole of the geographical space between the coast of South America and the meridian of New Zealand. Throughout this space the variation is easterly, and increases: we may consequently characterize the change in the situation of the lines of equal variation as a progressive closing-in {525} of the curves from all sides towards the centre, by which the areas severally comprehended by them become less; and the lower variations, as they successively reach the centre, disappear, and are replaced by the closing-in of those of next higher amount. The changes which have taken place at all Captain Fitz-Roy's stations comprised within the space referred to, are accordant with the systematic alteration thus described.

In all other parts of the hemisphere the lines of variation have a progressive westerly movement, and to this also Captain Fitz-Roy's observations correspond.

It follows, from what has been stated, that the lines on the western side of the concentric system in the South Pacific have an eastward movement, which presents an apparent anomaly to the general progress of the lines of variation in the southern hemisphere, which is from east to west.

Otaheite, and the Bay of Islands in New Zealand, present examples of changes in the variation corresponding to this apparent anomaly. The consistency, however, both of the movement and of the configuration of the lines of variation in this quarter, with those in other parts of the southern hemisphere, and with the general system of the magnetic phenomena, has been shewn by Mr. Hansteen in the Magnetismus der Erde, and in the Annalen der Physik, vol. xxi.

The annual amount of the change of the variation appears considerably greater at the Cape of Good Hope and Mauritius than at any other of Captain Fitz-Roy's stations, amounting to about eight minutes; shewing that the variation lines in that quarter are changing their position more rapidly than elsewhere. The north pole of the needle is moving to the west at the Cape, and to the east at Mauritius; but it will be seen, by a reference to the map, that these opposite movements are in perfect correspondence with the uniform westerly progression of the variation lines, and result from their configuration.

At the stations in the vicinity of the meridian of 65deg west, the change appears to be very small.

[The variation at Ascension (13deg 30' W.) is correctly inserted in the
tables: it is the only one of Captain Fitz-Roy's stations at which his
observations are not accordant with those of other observers: the
discordance may be occasioned by the great prevalence of local
disturbances at Ascension.]

{526}

II. _Dip._

The following table exhibits the comparison of Captain Fitz-Roy's observations of the dip in the southern hemisphere, with those of earlier observers, at stations where the materials for such a comparison exist.

ASCENSION. |
|
Observer. | Date.| Variation.| Observer. | Date.| Variation.
| | deg ' | | | deg '
La Caille | 1754 | 11. 10 N. | Luetke | 1827 | 45. 33 S.
Cook | 1775 | 8. 57 N. | King | 1829 | 45. 10 S.
Sabine | 1822 | 4. 30 N. | Fitz-Roy | 1835 | 43. 15 S.
Duperrey | 1825 | 1. 58 N. |
Fitz-Roy | 1836 | 1. 39 N. | KING GEORGE SOUND.
| Vancouver | 1791 | 64. 54 S.
ST. HELENA. | Flinders | 1801 | 64. 01 S.
La Caille | 1754 | 9. 0 S. | Fitz-Roy | 1836 | 64. 41 S.
Cook | 1775 | 11. 25 S. |
Fitz-Roy | 1836 | 18. 01 S. | VAN DIEMEN'S LAND.
| Cook | 1777 | 70. 15 S.
CAPE OF GOOD HOPE. | Bertrand | 1792 | 70. 50 S.
La Caille | 1751 | 43. 0 S. | Dentrecasteaux | 1792 | 70. 30 S.
Bayley | 1772 | 45. 37 S. | De Rossel | 1793 | 70. 10 S.
Bayley | 1775 | 45. 19 S. | Fitz-Roy | 1836 | 70. 35 S.
Abercrombie | 1775 | 46. 26 S. |
Bayley | 1776 | 46. 31 S. | SYDNEY.
Freycinet | 1818 | 50. 47 S | Flinders | 1803 | 62. 52 S.
Fitz-Roy | 1836 | 52. 35 S. | Freycinet | 1819 | 62. 47 S.
| Brisbane | 1821 | 62. 36 S.
MAURITIUS (PORT LOUIS) | Duperrey | 1824 | 62. 20 S.
La Caille | 1754 | 52. 17 S. | Fitz-Roy | 1836 | 62. 49 S.
Duperrey | 1824 | 53. 51 S. |
Fitz-Roy | 1836 | 54. 01 S. | N. ZEALAND (BAY OF ISLANDS).
| Duperrey | 1824 | 59. 45 S.
OTAHEITE. | Fitz-Roy | 1835 | 59. 32 S.
Cook | 1773 | 29. 43 S. |
Cook | 1774 | 29. 59 S. | TIERRA DEL FUEGO.
Bayley | 1777 | 29. 47 S. | Bayley } | |
Duperrey | 1823 | 30. 03 S. | Lat. 55deg.22'; } | 1774 | 66. 54 S.
Erman | 1830 | 30. 29.5 S| Long. 70. 03. } | |
Fitz-Roy | 1835 | 30. 13.5 S| King } | |
| Lat. 55deg.51'; } | 1828 | 59. 44 S.
LIMA AND CALLAO. | Long. 67. 34. } | |
Feuillee | 1710 | 10. 30 S. |
Humboldt | 1799 | 9. 59 S. | FALKLAND ISLANDS.
Duperrey | 1823 | 8. 33 S. | Freycinet | 1820 | 55. 20 S.
Fitz-Roy | 1835 | 7. 03 S. | Duperrey | 1822 | 54. 49 S.
| Fitz-Roy |1833-4| 53. 25 S.
VALPARAISO. |
Malaspina | 1793 | 44. 58 S. | STA CATHARINA.
Vancouver | 1795 | 44. 15 S. | Duperrey | 1822 | 22. 54 S.
Luetke | 1827 | 39. 56 S. | King | 1827 | 22. 12 S.
King | 1829 | 40. 11 S. |
Fitz-Roy | 1835 | 38. 03 S. | RIO DE JANEIRO.
| La Caille | 1751 | 20. 0 S.
CONCEPCION. | Freycinet | 1817 | 14. 42 S.
Feuillee | 1710 | 55. 30 S. | King | 1826 | 14. 00 S.
Perouse | 1786 | 50. 00 S. | Luetke | 1827 | 14. 35 S.
Duperrey | 1823 | 44. 55 S. | Erman | 1830 | 13. 31 S.
| Fitz-Roy | 1832 | 13. 37 S.

We may classify the changes which are taking place in the dip in the southern hemisphere in four divisions, characterised by an {527} alternate increase and decrease of dip. Commencing with the meridian of Greenwich, and proceeding eastwardly round the hemisphere, we may distinguish the divisions as follows, in the order of their geographical succession.

_1st. South dip increasing._

annually.
St. Helena 1754 to 1775 6,9'
Do. 1775 to 1836 6,5
Cape of Good Hope 1751 to 1775 7,2
Do. 1775 to 1836 6,6
Mauritius 1754 to 1824 1,3
Do. 1824 to 1836 0,8

To this division also belongs Ascension; but as the north end of the needle dips at that island, the change is _north dip diminishing,_ instead of _south dip increasing._

Ascension 1754 to 1775 6,3 annually.
Do. 1775 to 1836 7,2 --

_2d. South dip decreasing._

New Zealand 1824 to 1835 1,2 annually.[211]

_3d. South dip increasing._

Otaheite 1775 to 1836 0,5 annually.

_4th. South dip decreasing._

annually.
Lima and Callao 1710 to 1799 0,4'
Do 1799 to 1835 4,9
Valparaiso 1794 to 1835 10,0
Concepcion 1710 to 1786 3,7
Do. 1786 to 1835 8,3
Tierra del Fuego 1774 to 1828 8,0
Falkland Islands 1820 to 1834 8,2
St^a Catharina 1822 to 1827 8,4
Rio de Janeiro 1751 to 1817 4,8
Do. 1817 to 1832 4,3

In the 2d and 3d divisions the annual change is small; in the 1st and 4th considerably greater. It is greatest at the southern station in South America; the observations at Valparaiso, Concepcion, Tierra del Fuego, and the Falkland Islands, concur in shewing it to exceed 8'. The observations at Ascension, St. Helena, and the Cape of Good Hope, concur in shewing an annual change in that quarter of the 1st division exceeding 6'.

As the south dip decreases in South America, and increases in Africa, it is obvious that somewhere intermediately the dip must be stationary. Between Africa and New Zealand, for the same reason, there must be a second locality so characterised. Between New Zealand and Otaheite, a third; and between Otaheite and the west coast of South America, a fourth. Captain Fitz-Roy has {528} stations in the second of these localities only, between Africa and New Zealand. At Hobart Town, Sydney, and King George Sound, there appears to have been little or no change in the dip since the commencement of the present century.

The arrangement of the changes of dip in the southern hemisphere in four divisions, characterised by an alternate increase and decrease of dip, is in correspondence with the _double flexure_ of the lines of dip; and is a consequence of the western motion of the two southern magnetic poles.

Careful observations made at St. Petersburgh, have shewn that the annual change of the dip in the northern hemisphere takes place altogether between the months of May and December; there being in fact a small movement in an opposite direction between December and May. This fact is of great interest in its bearing on the study of the causes of the magnetic phenomena. We have as yet no corresponding knowledge in regard to the southern hemisphere. The magnitude of the annual change which Captain Fitz-Roy's observations show is now taking place at the Cape of Good Hope, is deserving of attention in this respect. A large amount of annual change is obviously highly favourable for a determination of all the circumstances belonging to it; and its existence at the Cape, where there is already a fixed observatory, points to that station as most eligible for this investigation.

The observations at Ascension shew that the epoch is fast approaching when the needle will pass from north to south dip at that island: it is extremely desirable that the period at which this change takes place should be determined with as much precision as possible.

III. _Intensity._

I have discussed in the Seventh Report of the British Association, the very important inferences in regard to the general distribution of magnetism in the southern hemisphere, afforded by Captains King and Fitz-Roy's most valuable series of intensity observations; but no inferences in regard to the _changes_ which this phenomenon may be supposed to undergo can be drawn, as has been done in the cases of the variation and dip, because we possess no observations of the intensity made at a sufficiently early period to afford good materials for such a comparison.

EDWARD SABINE.

* * * * *

{529}

CATALOGUE OF THE MORE INTERESTING SPECIMENS OF NATURAL HISTORY THAT WERE COLLECTED DURING THE VOYAGE.

------

MAMMALIA.

1. MUSTELA ZORILLA. Desm:[212]

The skunk. This animal was found abundantly on the coast of Patagonia, between Monte Video and Cape Gregory, at the eastern entrance of the Strait of Magalhaens. It appeared to be the same species throughout the whole extent of the coast.--Mus. Zool. Soc.

2. MUSTELA LUTRIS.--Lin.

_Lutra marina_, Steller. Erxleb. Harlan; _Enhydra marina_, Fleming.

The sea otter exists, but not very plentifully, on the coast of Tierra del Fuego; we saw very few. The Fuegian Indians hunt them with dogs which are trained for the purpose.--Museum Zool. Soc.

3. CANIS.

The dogs belonging to the Fuegian Indians are certainly of the domesticated kind, originally obtained, probably, from the Spanish settlements at Buenos Ayres; generally they resemble the Esquimaux breed, but are much more diminutive in size.

4. CANIS VULPES.

Two if not three distinct species of the fox were brought home; one, of a small size, was thought to be a novelty; the other, perhaps, was only remarkable for its large size. Mr. Vigors thought the small one was quite new; the last is perhaps _C. cinereo argenteus_.--Museum of Zool. Soc.

5. FELIS PUMA.

Several were seen: a skeleton was found on the shores of the Strait, supposed to be one of the above species.

{530}

6. FELIS PAJEROS.--Desm. E. M. p. 231.

Chat pampa, D'Azara, 1. 179.

A variety of this species was given to me, by the Patagonian Indians, that had been recently killed; the skin was preserved, and is now in the museum of the Zoological Society. The following is the description of my specimen:--

The prevailing colour is a yellowish grey, deeper above, and gradually blending into the colour of the belly, chin, neck, inner part of the legs, the region of the anus, and below the root of the tail, which are white; the under part of the neck and belly also are spotted with black, disposed in transverse bands; the fore arms have three similar transverse bands, and the thighs four encircling the legs; ears white inside and tipped black; eyes dark blue, eyelids whitish, corner of the eyes black, particularly at the anterior or inner angle; claws whitish, and paws black; whiskers white, and some long white hairs over the eyes; the canine teeth are very acute, and have the longitudinal grooves or angles deeply marked.

Inches.
Length of the body from the extremity of the nose
to the root of the tail 29
Length of tail 11-3/4
Ditto head 6
Breadth of head between the ears 2-7/8
Height at the shoulder 12

7. OTARIA JUBATA.--Desm. E. M. No. 380.

The sea lion of Anson and other voyagers; numerous in the eastern entrance of the Strait, and particularly at Port San Julian and the neighbourhood of Port Desire.

8. OTARIA FLAVESCENS.--Desm: E. M. 250.

A young male was found on the beach, near Port Famine, that had been recently wounded by the Indians, and had crawled on shore to die.

9. CTENOMYS MAGELLANICUS. n. s.--Bennet.

This little animal possesses fur as soft as the chinchilla. It abounds in the neighbourhood of Cape Gregory, at the eastern entrance of the Strait of Magalhaens, and burrows under the {531} ground, which is so much undermined by them that it gives way at almost every step. It is a timid little fellow, feeds upon grass, and is eaten by the Patagonian Indians.--See Bennet in the Proceedings of the Zool. Soc. Dec. 22, 1835. A specimen is preserved in the Museum.

10. KERODON KINGII. n. s.

See Bennet ut supra, in Museum of Zool. Soc.

11. CAVIA CUTLERI, n. s. nob.--See Bennet ut supra.

This specimen is in the collection of the Society. It was known in the voyage by the name of the Peruvian cavy: it was presented to one of the officers of the Beagle by an American sailing master, Mr. Cutler, of Stonington, U.S., a very intelligent person, to whom we are much indebted for information. The name which I have proposed for it is in recollection of the benefit we derived from his experience and knowledge of the intricate navigation of the south-western coast of Patagonia, which was freely imparted to us on several occasions.--See Bennet in Proceedings of Zool. Soc. ut supra.

12. DASYPROCTA PATACHONICA.--Desm. E. M. 358.

I regret very much that the only specimen obtained was not preserved. Desmaret seems to suspect that it differs sufficiently in its dentition from the agouti to constitute a new genus, for which he has proposed the name _Dolichotis_.--See E. M. 359.

13. DASYPUS MINUTUS.--Desm.

Procured at Port Sta Elena, and corresponds exactly with the description of the above species. It is the Tatou pichiy, or Tatou septieme of D'Azara.

14. AUCHENIA GLAMA.--Desm. E. M. 655.

A living female guanaco was brought home in the Adventure, and placed in the garden of the Zoological Society. The guanaco inhabits Patagonia from Buenos Ayres to the Strait of Magalhaens: we also found it on King Charles Foreland, the eastern island of Tierra del Fuego, and on Navarin Island, at the north side of Nassau Bay, in the vicinity of Cape Horn.

* * * * *

{532}

BIRDS.

1. SARCORAMPHUS GRYPHUS.--Dumeril. The Condor. _Vultur Gryphus._--Lin.

2. CATHARTES IOTA.--Chilian Eagle.

3. POLYBORUS VULGARIS.--_Falco Brasiliensis._ Latham. Caracara Eagle.

Strait of Magalhaens.

4. MILVAGO OCHROCEPHALA.--Spix. Young birds.

Strait of Magalhaens.

5. HALIAETUS ERYTHRONOTUS.--Nob. in Zool. Journal, iii. 424.

_Hal. capite alisque fusco-griseis; dorso scapularibusque rufis,
corpore caudaque subtus albis, fasciis fuscis gracilibus leviter
notatis, hac fascia lata prope apicem nigra._

The total length of the bird from the _apex_ of the bill to the extremity of the tail is 2 feet; of the bill from the _rictus_ to the _apex_ 2 inches; from the cere 1 inch; of the wing, from the end of the carpal joint to the end of the third quill feather, 18 inches; of the tail 10-1/2 inches; of the _tarsus_ three inches.

Strait of Magalhaens.

6. FALCO SPARVERIUS.--Latham.

Strait of Magalhaens.

7. FALCO PEREGRINUS?

Strait of Magalhaens.

8. POLYBORUS BRASILIENSIS.

Polyborus Novae Zealandiae.
Falco Novae Zealandiae of Latham.

9. CIRCUS HISTRIONICUS.--Nob. in Zool. Journal, iii. 425.

_Falco histrionicus_, Quoy and Gaimard.

_Circo cineraceus uropygio corporeque subtus albis: hoc fasciis
frequentibus rufis notato._

The length from the _apex_ of the bill to that of the tail is 18 {533} inches; bill 1 inch; wing, from the carpal joint to the end of the third quill feather, 13-1/2 inches; tail 9 inches; _tarsus_ 2-1/2 inches.

Strait of Magalhaens.

10. STRIX RUFIPES.--Nob. in Zool. Journ., iii. 426.

_Str. saturate brunnea, albido fulvoque maculata fasciataque femorum
tarsorumque plumis rufis._

The total length is 15-1/2 inches; that of the bill 1 inch; of the wing, from the _carpus_ to the end of the fourth quill feather, 11 inches; of the tail 7-1/2 inches; of the _tarsi_ 2-3/8.

11. STRIX NANA.--Nob. in Zoological Journal iii. 427.

_Str. fusco brunnea, fronte nucha alisque albo-notatis, gula alba,
cauda fasciis frequentibus rufis notata._

The total length is 5-4/5 inches; of the bill 1/2 inch; of the wing, from the _carpal_ joint to the extremity of the fourth quill feather, 3-3/4 inches; of the tail 2-3/4 inches; of the _tarsi_ 7/8.

_N.B._--Three other species of this genus are in the collection which appear to be new.

12. HIRUNDO.--Sp.*

13. HIRUNDO.--Sp.*

14. HIRUNDO.--Sp.*

* Three distinct species of swallow, very much resembling the British species,--_Hir. rustica_, _urbica_, and _riparia_.

Strait of Magalhaens.

15. TURDUS MAGELLANICUS.--Nob. in Proceedings of Zool. Soc.

_Turd. corpore supra grisescenti olivaceo, subtus pallide rufescenti,
capite supra, remigibus, caudaque fusco-atris gula-alba, fusco-atro
lineata._

Strait of Magalhaens.

16. SYNALLAXIS ANTHOIDES.--Nob. in Proceedings of Zool. Soc.

_Syn. supra brunnea plumis in medio fusco late striatis, tectricibus
alarum superioribus rufo tinctis subtus pallide cinerea; rectricibus
lateralibus ad marginem externum, fasciaque alarum, rufis. Statura.
Syn. Spinicaudae._

Strait of Magalhaens.

17. SYLVIA SPINICAUDAE.--Latham.

{534}

18. SYLVIA DORSALIS.--Nob. in Zool. Journ. iii. 428.

_Syl. nigra, dorso scapularibusque rufis, remigibus rectricibusque
fuscis._

The length from the end of the bill to that of the tail is 4-1/2 inches.

19. SYLVIA OBSCURA.--Nob. in Zool. Journ. iii. 429.

_Syl. corpore unicolore fusco-nigro, alis brevibus rotundatis cauda
brevi, pedibus elongatis, fortibus pallidis._

The length from the apex of the bill to that of the tail is 4-1/4 inches; of the wing, from the carpal joint to the end of the fourth quill feather, 1-7/8; of the tail 1-1/4; of the _tarsi_ 3/4.

20. TROGLODYTES.

21. FRINGILLA.--(Several species, probably new.)

22. STURNUS MILITARIS.--Lin.

MOTACILLA PATACHONICA.---Lin.
Patagonian warbler of Dixon's voyage.

23. STURNUS.--Sp. (black)? Leistes sp. Vigors.

24. DENDROCOLAPTES ALBO-GULARIS. Nob. in Proceedings of Zool. Soc.

_Dend. corpore supra, abdominisque lateribus, rufo brunneis; remigibus
secundariis, dorso imo, caudaque rufis; mandibula inferiori ad basim,
gula, jugulo, pectore, abdomineque medio, albis, hujus plumis brunneo
ad apicem marginatis; rostro sursum recurvo._

Length 6-4/10 inches.--Strait of Magalhaens.

25. PSITTACUS SMARAGDINUS.--Gmel.

26. PSITTACARA LEPTORHYNCA. Nob. in Proceedings of Zool. Soc.

_Psitt. viridis: fronte, striga per oculos, caudaque rufis: capite
nigro, abdomine imo rufo, variegatis; mandibula superiori elongata,
gracillima._

Statura.--_Psitt. Lichtensteinii aequalis. Habitat in insula_ Chiloe.

27. PICUS MAGELLANICUS.--Nob. in Zool. Journ. iii. 430.

_Pic. niger, capite cristato colloque coccineis, remigibus albo
notatis._

Foem. _Capite cristato nigro, fronte mentoque coccineis._

{535}

The length of the bird from the tip of the bill to the extremity of the tail is 17 inches; of the bill 2-1/2; of the wing, from the carpal joint to the fourth quill feather, 8-3/4; of the tail 7-1/2; of the _tarsi_ 1-1/8; of the external hind toe, the nail included, 2.

Strait of Magalhaens.

28. PICUS MELANOCEPHALUS.--Nob. in Proceedings of Zool. Soc.

_Pic. capite corporeque supra nigris, hoc albo maculato; pectore
abdomineque albis, illo albo lineato, hoc albo fasciato._

Length 6 or 7 inches.--Strait of Magalhaens and Chiloe.

29. MELLISUGA KINGII--Vigors in Zool. Journal, iii. 432.

_Ornismya sephanoides._--Lesson et Garn.

_Mell. supra metallice viridis, infra alba viridi variegata, vertice
splendide rubeo, rectricibus acuminatis._