Proceedings of the expedition to explore the northern coast of Africa, from Tripoly eastward

by Frederick William Beechey; H. W. Beechey

Mean rate.One of the reasons to which this great improvement in ancient vessels may be attributed, appears to be clearly stated by Pliny himself, in the Proemium from which we have selected the examples here[19] adduced: we allude to the increased number and size of the sails in use, at the time when the historian flourished, as noticed in the preface in question attached to the nineteenth book.

Before entering upon the dissertation on flax, with which this book opens, the Roman naturalist indulges himself in calling to mind some of the extraordinary effects resulting from the various applications of that humble and unassuming plant; and gives way to his feelings with so much enthusiasm and good sense, that it will not, we think, be considered tedious or superfluous, if we extract the greater part of the preface from the old English translation of Holland[20].

It seems evident from the remarks here quoted below, that the rate of sailing in Pliny’s time was greatly superior to that which has been given (from the Illustrations of Herodotus) down to the time of Alexander the Great; and when we find that other voyages described by this author (as well as those which various writers of his time have recorded) fall short of the rate of sailing deduced from the last mentioned instances; we may probably be allowed to make the following conclusion—that the difference did not really so much consist in the faulty construction of the vessels themselves, or the little sail which they were able to carry, as in circumstances which would equally contribute to retard ships constructed in modern days. At the same time we may suppose that the voyages here enumerated by Pliny were performed under the most favourable circumstances which could be commanded. They were government vessels, and probably equipped in the most liberal and judicious manner possible at the time; they were navigating a sea which long habit must have rendered familiar to them, and where they must have known the best courses to be steered under every change of weather and season. The voyages were not sufficiently long to be retarded by want of provisions, and the confidence resulting from experience and comparative security would have induced them to carry all the sail they could command without hesitation or dread. Under these circumstances we may also suppose that the day intended was twenty-four hours, and indeed, in the passage to Alexandria, and other parts of the African coast, it could scarcely have been any other.

OBSERVATIONS ON ROAD MEASUREMENTS DEDUCED FROM THE ORDINARY WALKING PACE OF HORSES AND CAMELS.

Independent of the operations for laying down the coast, an account of the various windings of the road travelled by the camels was regularly kept by Lieutenant Coffin as far as Bengazi.

This was done by observing the direction of their route by compass, and noticing the time they were on the road; proper deductions being made for stoppages, &c. At the end of each day the courses and distances were collected into a traverse-table, and the latitude and longitude deduced therefrom, as is usual with the D.R, on board ships at sea. If the latitude by these means differed from the observation, a proper correction for error in course, distance, or both was made, and the result noted accordingly.

A more favourable opportunity of proving the dependance that may be placed on such a reckoning on land, could not, in all probability, have offered itself; as the extent of each day’s progress was accurately determined by the means adopted for carrying on the survey. And it may be useful to future travellers, as well as to those persons who may have to compile maps from camel journeys, to insert an abstract of the different days’ works, compared with the latitude and longitude by observations, which will be found annexed.

By this Table it will be seen that the average rate of travelling has not exceeded two miles and a half per hour, and that at the end of the journey from Mesurata to Bengazi, a distance of four hundred and twenty-two miles, there is only a difference of 9′ in the longitudes. This is an error so small, that there are few persons who would object to the accuracy of the places laid down by the means employed, and yet there are many who would feel inclined to dispute the accuracy of the average rate. But the truth is that, in travelling through countries in general, there are so many things to obstruct a direct track, that, though an animal may actually pass over the ground at the rate of three or three and a half miles per hour, as the camel in reality does, yet, in estimating the distance for a traverse-table, great deductions must be made, or our reckoning will far exceed the truth[21].

The journey round the Syrtis having satisfied us with respect to the rate which might be allowed, and the accuracy that was to be expected under general circumstances, we determined to ascertain what precision we could arrive at when the direction of the road and nature of the ground were the most favourable. For this purpose we kept a track from Bengazi to Ptolemeta; and having occasion to go over the same ground a second time and return, we had three measurements between the places independent of that of the chronometers[22], which, as well as those of the intermediate stations, agree together and with the truth, to an exactness which we did not expect; and will serve to show that, under favourable circumstances, and when attention is paid to the rates of the camels, the topography of a country may be laid down sufficiently accurate for most purposes. We should have informed our readers, that the track from Bengazi to Ptolemeta is particularly straight, and encumbered with as few obstructions as are likely ever to occur in a country where, properly speaking, no road exists.

TABLE OF DISTANCES MEASURED BY CAMELAND HORSE PACE.
Left.			Arrived.			Interval		Rate per hour.	Distance	REMARKS, &c.
Place.	Time.		Place.	Time.
	H.	′		H.	′	H.	′	Miles.
Teuchira	10	10	Wady	12	00	1	50	3½	6¼	⎫ ⎬ ⎭	These distances are by horsepace.
Wady	12	00	Wady	1	00	1	00	„	3½
Wady	1	00	A Fort	3	10	2	10	„	7½
Fort	4	00	Ptolemeta	6	25	2	25	2½	6¼		This by camel pace.
			Whole distance					=	23½		From Teuchira to Ptolemeta.
Bengazi	7	00	Aziana	9	15	2	15	3	6¾	⎫ ⎬ ⎭	Camel pace.
Aziana	9	15	Birsis	5	08	7	53	3	23¾
Birsis	6	10	Teuchira	8	30	2	20	3	7
			Whole distance					=	37½		From Bengazi to Teuchira.
Teuchira	8	30	Wady El Assa	11	25	2	55	3	8¾	⎱ ⎰	Horse pace.
Wady El Assa	11	25	Ptolemeta	4	10	4	45	2¾	13¼
			Whole distance					=	22		From Teuchira to Ptolemeta.
Ptolemeta	7	10	Wady El Assa	11	07	3	57	3¼	13	⎱ ⎰	Horse pace; camels arrived an hourafter.
Wady El Assa	11	07	Teuchira	1	45	2	38	„	8⅛
			Whole distance					=	21⅛		From Ptolemeta to Teuchira.
Teuchira	7	00	Birsis	9	10	2	10	3	6½	⎫ ⎪ ⎬ ⎪ ⎭	Single camel.
Birsis	9	10	Handoola	4	00	6	50	3	20¼
Handoola	7	00	Aziana	8	00	1	00	2¾	2¾
Aziana	8	00	Bengazi	10	25	2	25	2¾	6¾
			Whole distance					=	36¼		Teuchira to Bengazi.
From			To
Teuchira			Ptolemeta						23½		By first measurement.
Ditto			Ditto						22		By the second.
Ditto			Ditto						21⅛		By the third.
Ditto			Ditto						22⅕		Mean.
			Actual distance						22		By observations of latitude and longitude.
Teuchira			Bengazi						37½		By second measurement*.
Ditto			Ditto						36¼		By third.
									36⅜		Mean.
			Actual distance						34½		By latitude and longitude.
And by these the wholedistance,
From			To
Bengazi			Ptolemeta						59½		By one measurement.
Ditto			Ditto						57⅜		By the other.
									58½		Mean.
			Actual distance						56½		By latitude and longitude.
*The first measurement fromBengazi to Teuchira is omitted, in consequence of the camels havingdeviated a little from the road afterwards travelled.