Kitabı oku: «The Albert N'Yanza, Great Basin of the Nile, And Explorations of the Nile Sources», sayfa 34

APPENDIX

COMPUTATION OF MR. BAKER'S OBSERVATIONS.

HEIGHTS OF STATIONS ABOVE THE MEAN LEVEL OF THE SEA DETERMINED BY BOILING-WATER OBSERVATIONS BY S. W. BAKER, Esq. COMPUTED BY E. DUNKIN, Esq. OF GREENWICH OBSERVATORY. Feet.

Tarrangolle. . . . . . . . . . . . . . . . . . . . . . . . . . 2047

Obbo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3480

Shoggo . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3770

Asua River . . . . . . . . . . . . . . . . . . . . . . . . . . 2619

Shooa . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3619

Rionga's Island . . . . . . . . . . . . . . . . . . . . . . . 3685

Karuma, below falls . . . . . . . . . . . . . . . . . . . . . 3737

Karuma, south of falls . . . . . . . . . . . . . . . . . . . . 3796

South of Karuma, at river level. . . . . . . . . . . . . . . . 3794

M'rooli, river level, junction of Kafoor . . . . . . . . . . . 3796

West of M'rooli, on road to Albert lake . . . . . . . . . . . 4291

Land above lake, east cliff . . . . . . . .. . . . . . . . . . 4117

Albert N'yanza, lake level . . . . . . . . . . . . . . . . . . 2448

Shooa Moru, island of Patooan . . . . . . . . . . . . . . . . 2918

Gondokoro . . . . . . . . . . . . . . . . . . . . . . . . .. . 1636

The above heights will be found to differ considerably from those given by Mr. Baker in his letter written from Khartoum in May, 1865, and published in the TIMES newspaper in June. This arises from Mr. Baker having corrected his observations, whilst in the interior of Africa, from what have since proved erroneous data: the above are the correct computations of the same observations.

REMARKS ON THE THERMOMETER B. W. USED BY MR. S. W. BAKER IN DETERMINING HEIGHTS. By Staff-Commander C. George,

Curator of Maps, Royal Geographical Society.

This thermometer was one of the three supplied by the Royal Geographical

Society to Consul Petherick, in 1861, and was made by Mr. Casella.

At Gondokoro, in March, 1862, it was lent to Mr. Baker, who made all his observations with it, and brought it back safe: it has, therefore, been in use about 4 and 3/4 years.

On November 9th, 1865, Mr. Baker returned it to the Royal Geographical Society, and it was immediately taken to Mr. Casella, who tested its accuracy by trying its boiling-point, in nearly the same manner as Mr. Baker had made his observations. The result by two independent observers was that the boiling-point had increased in its reading by 0 degree point 75 in 4 and 3/4 years, or 0 degree point 172 yearly.

On November 23d the thermometer was again tested by Mr. Baker at the Kew Observatory. The observation was made under the same conditions as those near the Albert N'yanza, as nearly as it was possible to make it. (By immersion in boiling water.) The result gave the thermometer 0 degree point 80 too much at the boiling-point.

The readings of the thermometer have, therefore, been TOO MUCH; and by REDUCING the readings, it ELEVATES all positions at which observations were made.

Table No. 1.—In this Table the error obtained at Kew Observatory has been treated like that of a chronometer, the error being assumed increasing and regular.

Table No. 2 is to correct the height, computed by Mr. Dunkin, using the quantity taken from Table No. 1.

Table No. 3 is the final result of the observations for height, corrected for instrumental error.

TABLE No. 1.

Table for Increased Reading of Thermometer, using 0 degrees 80 as the

Result of Observations for its Error.

Month. 1861. 1862. 1863. 1864. 1865.

January. . . – 0'143 0'314 0'487 0'659

February . . – '157 '328 '501 '673

March . . . 0'000 '172 '344 '516 '688

April . . . '014 '186 '358 '530 '702

May . . . . '028 '200 '372 '544 '716

June . . . . '043 '214 '387 '559 '730

July . . . . '057 '228 '401 '573 '744

August . . . '071 '243 '415 '587 '758

September . . '086 '257 '430 '602 '772

October . , . '100 '271 '444 '616 '786

November . . '114 '285 '458 '630 0'800

December . . 0'129 0'300 0'473 0'645 —

TABLE No. 2.

At the elevation of 3,500 feet, 1 Degrees equals about 520 feet, from which the following—

Degrees Feet. Degrees Feet Degrees Feet.

1'0 . . . 520 '7 . . . 364 '3 . . . 156

'9 . . . 468 '6 . . . 312 '25 . . . 130

'8 . . . 416 '5 . . . 260 '2 . . . 104

'75. . . 390 '4 . . . 208 '1 . . . 52