The results of my survey of the countries between India and the Caspian Sea are exhibited on the face of the map: the data on which these results rest require to be stated, that others may be enabled to judge of the authenticity of the document.
The instruments used were, a sextant, of nine inches radius, by Gilbert, and the patent surveying compass of Schmalcalder, divided into 360 degrees. With the sextant the parallels of latitude were determined, when practicable, either by a meridian altitude of the sun, or the elevation of the pole star; with the compass the bearings or angles of the country were observed. The time of travelling was noted on the spot, from a valuable chronometer watch by Arnold.
The rate of marching, after various trials by astronomical observation, was found to be as follows:—
1st. On horseback, over a level country, such as the Punjab, or regions eastward of the Caspian, without a caravan, 30 furlongs, or 3¾ miles per hour.
2d. On horseback, over a broken or mountainous country, such as lies between the Indus and Cabool, and accompanied by mules lightly laden, 3 miles per hour.
3d. On camels, over a flat country, such as Toorkistan, about 3800 yards, or 2 miles 300 yards per hour; protracting in every instance the great inflexions of the road, and correcting them by peaks or notable land-marks in front or rear.
The rate of a camel’s march requires some further notice, since I took much pains to ascertain it, and am not without a hope that it may prove useful to others. Twenty-two camels in “kittar,” or string, that is, following and tied to each other, cover a space of 115 paces of 2½ feet, or 94 yards. They march over this space in 90 seconds of time; that is to say, they travel at the rate of 76⅔ paces per minute, or 3833 yards per hour, thus:—
| 76⅔ | paces a minute. |
| 60 | minutes. |
| —— | |
| 4560 | |
| 40 | |
| —— | |
| 4600 | paces. |
| 2½ | feet. |
| ——— | |
| 3)11,500 | feet. |
| ——— | |
| 3833 | yards. |
| ——— |
Camels move quickest at night, or in the cool of the morning, and flag after a march of twenty-five miles. I have, therefore, taken the even number of 3800 yards as my standard of protraction. I cannot agree with Mr. Macartney, that camels move at the rate of 2½ or 2¾ miles an hour. Volney informs us that the Syrian camel travels at the rate of only 3600 yards, or even lower than the standard which I have assigned; and that great traveller cannot be far from the truth. In a sandy country I used the following expedient to ascertain the rate of the camel, and the result presents a satisfactory approximation.
| A string of | 7 | camels moves over its own ground in | 26 | seconds. |
| 10 | 42 | |||
| 7 | 28 | |||
| 8 | 35 | |||
| 8 | 37 | |||
| 12 | 50 | |||
| 52 | 218 |
Each camel in string occupies about 13 feet; so that 52 camels cover 676 feet, which gives a rate of about 3700 yards an hour in soft ground; thus:—
| sec. | feet. | sec. | ||||
| If | 218 | : | 676 | : | 3600. | Ans. 3700. |
That the rates of marching now recorded approximate closely to the truth, is undeniably established by my protraction to the city of Bokhara, which fell within 30 miles west of the meridian of 64° 55′ east longitude, the position assigned to it by the Russian mission. In Macartney’s map it stands in 69° 10′, and was altered by Mr. Elphinstone to 62° 45′; though that gentleman observes he was not satisfied with its position. The latitude of Bokhara I found to be 39° 43′ 41″ north; but its position, according to others, is somewhat different.
| By Lt. Macartney | 37° | 45′ North. |
| By Mr. Elphinstone | 39 | 27 |
| By Major Rennell | 39 | 25 |
| By Anthony Jenkinson | 39 | 10 |
I also found a remarkable coincidence with the correct longitude, in my protraction through the Toorkmun country, from Meshid to the Caspian Sea. Setting out also from Lodiana in India, which stands in 75° 54′ east longitude, and 30° 55′ 30″ north latitude, the protraction to Peshawar was nearly coincident with the position of that city as determined by the Cabool mission. They assigned to it the longitude of 71° 45′: I have placed it 71° 33′: it stands in 34° 9′ 30″ north latitude. The relative position of Cabool from Peshawur has been altered, as well as the ranges of the mountains; but it is unnecessary to detail the various changes which an inspection and comparison of the map will readily point out. With the assistance of Mr. John Arrowsmith, whose maps have already secured to him a just approbation[19], the materials of my survey have been incorporated with the latest geographical information: this will greatly enhance the value of the maps, which have been drawn by Mr. Arrowsmith himself, and carefully engraved under his own superintendence for this work; nor will it in any way conceal the later information, since my own line of route has been particularly marked and distinguished from that of other travellers.
The following original observations of latitude it seems advisable to record. The asterisk marks those which were observed at night.