which image is the immediate caufe of vifion. That fuch object appears greater or lefs, in proportion to the magnitude of its image, the fize of which depends on the angle under which the object is feen. Hence it follows, that an object is greater or lefs in proportion to its distance from the eye; and of course that the fame object will appear lefs when it is far off, than when it is near. This being admitted, the learned Writer above mentioned asks, at what diftance objects must be viewed, fo as to appear of their real magnitude? This queftion he affirms to be unanswerable; there being no rules for determining fuch diftance. For, continues he, with regard to us, magnitude is relative; that is to fay, feveral quantities being given, we may perceive whether they are equal or unequal to each other; and, if unequal, may often acquire the knowlege of their relation: but this knowlege doth by no means lead us to that of the real or abfolute value of fuch quantities, or the actual magnitude of objects, confidered in themfelves as independent of, and uncompared with, others. We have no other means of acquiring the knowlege of the magnitude of objects, but those of the measures in common ufe, and which ferve' to determine the relative magnitude of fuch objects. But the abfolute extent of even these measures is not known to us, and is impoffible to be fo. The length of a foot, indeed, we know to be fix times Jefs than a toife, and to be twelve times greater than an inch; but how fhall we find out the abfolute extent of a foot, abftracted from all methods of comparing it, either with a toife, an inch, or any other measure fmail or great?.

In reply to thefe arguments of Father Feijus, our philofopher tells us, that it is not neceflary to know the abfolute magnitude of external object, abftracted from all comparifon, in order to determine whether we fee them in their real or true magntiude. To fee an object in its true magnitude, nothing more is required, than that the impreffion made on the tetina, or immediate organ of vifion, should equal the fize of the object. Now this equality, fays he, may be known, without our knowing the abfolute extent of either the object or impreffion. For, by applying two equal furfaces to each other, we may juftly fay that the one touches the other in every part of its real magnitude: thus, if the hand be immediately applied to the furface of an half-crown, we are certain it touches the whole fuperficies, fince that part of the hand immediately affected by it, is equal to the furface of the coin. In the fame manner, fays our Author, if it could be fhewn that the furface of the retina, which immediately receives the impreffion of any object, or, which is the fame thing, that the furface on which the image of the obje is formed, is equal to the furface of the object itself, we

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fhould

hould be certain that we faw the object in its true magnitude, altho' we should be ignorant what that magnitude might be.

Our Author brings many arguments in fupport of his opinion; all which, however, are much more ingenious than fatiffactory. He feems, indeed, to have made a diftinction between the real and abfolute magnitude of objects, for which there is no ground: at least, it is evident to us, that his adverfary conceived thofe terms to be fynonimous. According to his own fyftem alfo, the reality of magnitude which he contends for, is dependent on the optics of the perceiving animal: for he admits that objects do not, even at the fame distance, appear of equal size to all animals. What then is the real magnitude of fuch objects are they as big as they may appear to an elephant, or as they appear to a mite? To animals, fays our Author, who have large eyes, objects appear larger than they do to those who have fmail eyes; fo that the apparent diameter of the same object feen by one animal, is to the apparent diameter of the fame object feen at the fame diftance by another animal, as the diameter of the eye of the first is to the diameter of the eye of the fecond. Let us compare, for example, the eye of a man and that of an ox, and we shall find that the diameter of the former is about three quarters of the diameter of the latter. For I have measured the eyes of many oxen, and find them to be from 16 to 17 lines: the diameter of a man's eye is ufually about II lines of confequence, that of an ox's eye bears a proportion to it nearly as four to three. It is evident, therefore, ceteris paribus, that the fame object feen at the fame diftance, will appear to the ox about a fourth part bigger than it doth to the nian." Suppofing, therefore, our ingenious Author to be in the right with regard to his criterion of determining the magnitude of objects, as they exift dans leur etat naturel, yet as they appear even in their natural state of different magnitudes to different animals, their real or abfolute magnitude is purely relative, as Father Feijus afferted; their real or true magnitude, in the notion of our Author, being no more than their uniform relation to other objects, and the organs of the perceiving animal.

Section the eleventh relates to feveral experiments and obfervations on the afcent and defcent of fluids in capillary tubes, and are well worth the attention of the curious.

In the twelfth and laft fection, our Author endeavours to fhew the incompatibility of the globular form of drops of liquor, with the fyftem of attraction. On this fubject, however, he difplays, as we have before hinted on others, much more ingethan judgment. We fhall here, therefore, take our leave this reverend Father's Phijofophical Amusements.

ity

Journal

Journal Hiftorique du Voyage fait au Cap de Bonne-Efperance, par feu M. l'Abbé de la Caille, d' l' Academie des Sciences. Précédé d'un Difcours fur la Vie de l'Auteur. i. e.

An hiftorical Journal of a Voyage to the Cape of Good Hope. By the late Abbé de la Caille. To which is annexed, a Difcourfe on the Life of the Author. Together with Remarks and Reflections on the Cuftoms of the Hottentots, and other Inhabitants of the Cape. Paris, 1763.

Tis fome mortification, after having long thought ourselves

I pretty well informed of the general character and customs of

any people, to learn, from more fenfible, or more ingenuous, Travellers, that we have been all the while impofed on, by the falfe, or hearfay, relations of mere Voyagers, who have written. without candour, and without capacity. To this mortification, however, will many of the Readers of this Journal be subjected, when they come to find, that the Defcription of the Cape of Good Hope, by the celebrated Peter Kolbé, which hath hitherto been deemed fo generally authentic, is full of the most notorious impofitions and mifreprefentations.

The character of the prefent Writer, and the occafion of his voyage to the Cape of Good Hope*, are too well known to need our expatiating on either. How far he fucceeded in the execution of his commiffion, as an Aftronomer, the learned world have been long fince apprifed of. As that alfo was the most immediate object of his voyage, it is reafonable to fuppofe the publication of this Journal was, during the Author's life, neceffarily delayed by more important concerns. We cannot help regretting, nevertheless, that the papers here published, were not digefted for the prefs by the ingenious Author himself; in which cafe, we make no doubt, that they would have afforded a very just and entertaining account of the Cape and its inhabitants. Indeed, the Public would have been obliged to the Editor, had he taken the pains to have thrown the Abbé's remarks on Kolbe's defcription, &c. into his narrative; it being of very little confequence to Readers in general, to know, that a Writer, in advancing the truth of facts, contradicts fome other who may have mifreprefented them by advancing falfhoods.

- Our learned Voyager's Journal begins the 21st of October 1750, when he fet out from Paris, and ends the 28th of June 1754, when he returned to that city; having been abfent just three years, eight months, and one week. The Reader will find it lefs dull, and more inftructive, than fuch Journals usually are; tho' we do not meet with any thing peculiarly worth our felecting, unless it be the following account of the method of

In order to measure a degree of the earth, and tale obfervations of the ftars in the fouthern hemifphere.

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bunting

hunting the elephant; as it was given to M. de la Caille, by the perfon who actually caught one of thofe animals; a tooth of which our Author brought home with him to Paris.

The clephant is always fought for, by the hunters, on the banks of rivers; where he is attacked in the following manner, Three horfemen, well mounted, fet out on the expedition, Two of them ride about the plain, while a third carefully watches the elephant, as he goes to drink at the neighbouring river; when, having given notice to his companions, he begins the attack, by piercing the fide of the beaft with his javelin, while he is drinking. On this the wounded animal immediately puriues the aggreffor, who rides directly toward his companions on the plain: when one of them attacks the elephant in his turn, in order to divert his attention from the object of his purfuit. Accordingly the beaft, enraged anew by a fresh wound, neglects his firft antagonist, and purfues the fecond; when the third perfon draws him off from the purfuit of the fecond, by the fame means as the fecond diverted him from that of the first. In the mean time, the poor creature lofes a vast quantity of blood; which the fury and agitation he is put into, caufe to flow in great abundance. If he furvives thefe three attacks, the first hunter attacks him again; and thus is the poor beaft engaged by their fucceffive affaults, till wearied out and faent with the lofs of blood, he falls to the ground. In this fituation there is no danger in approaching this formidable animal; and fawing off his teeth, whofe length is proportioned to the age and ftrength of the beaft.

But this method of hunting the elephant, is extremely dangerous, if attempted on rough ground, as appears by the following relation. Three Dutchmen, who had lived fome time at the Cape, and got a great deal of money by this kind of bufinefs, being about to return to their native country, had a mind to take their leave of the fport, by one more hunt, for their diverfion. To this end they fixed on a plain which, unluckily, was not fufficiently fecured from the mole hills, which are very large and hollow in that country. The chafe began fucceff fully; the fecond hunter having given the attack, and got to fome distance from the elephant, when his horfe ftumbled at a mole-hill, and fell; giving the furious animal time to come up to him when the latter feized hold of the rider with his trunk, and threw him on the ground. Then feizing the horse in the fame manner, he threw him to a confiderable distance: after which, returning to the dismounted hunter, he took hold of I'm again, and teffing him up in the air, caught him, as he fell, he point of one of his tufks, which ran fairly through his and thus held him empaled by the middle. In this fitua

tion, the favage animal kept him a long time, turning him felf about, and prefenting the horrid fpectacle to his other purfuers; at the fame time feeming to take a pleafure in the writhings, cries, and fufferings of this unfortunate hunter.'

In the account given of the manners and cuftoms of the Hottentots, we meet with the following general obfervations reSpecting this people; which fet them, by no means, in fo unfavourable a light as fome accounts heretofore given us.

The Hottentots live much in the fame manner as the an cient Gauls, mentioned in Cæfar's Commentaries; refiding in different hords or tribes, on the banks of rivers, and near the forefts; where they form fo many distinct villages and independent republics. By means of the rivers, the country about them is fertile in the production of those roots and wild fruits on which the Hottentots in a great measure fubfift; and the forefts yield them the like advantages, tho' thefe only resemble our fhrubberies, their trees being seldom more than fix or seven feet high. The Hottentot villages are all circular; the cabbins of which they are compofed, being covered with skins, and fo very low, that a man muft either ftoop very much, or crawl on his knees, to get into them. They ferve, indeed, chiefly to contain provifions, and their implements of husbandry; the owner himself never occupying them unless when it rains: at other times, he paffes his leisure hours in fleeping at the door of his hut; where he lies on his belly, and expofes his back to the fun and the weather; waking now and then to amuse himself with fmoaking a certain ftrong-fcented herb, which hath much the fame effect as our tobacco. The employment of the Hottentots is purely paftoral; their principal and almost only occupation being the care of their herds of sheep and kine. Óf these each village hath one common herd, every inhabitant taking it in his turn to be herdfman. This charge requires a great many precautions, very different to those which are taken by our herdsmen with us; beafts of prey being much more numerous and fierce in the fouthern parts of Africa than in Europe. Lions, indeed, are not very common there; but there are leopards, tygers, and feveral kinds of wolves, more destructive than ours, together with many other furious animals that abound in the forefts, and occafionally make excurfions toward the Cape, and deftroy the tame cattle. To prevent thefe misfortunes, it is the business of the herdfman to go, or fend, every day round his diftrict, in order to difcover if any beaft of prey be lurking in that quarter. In which cafe, he affembles the whole village together, and makes his report; when a party of the ftouteft among them, arm themfelves with javelins and poifoned arrows, and follow the perfon who may have difcovered the beaft,

to