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likely to die, and that special precautions had to be taken to save it, the author suggested that we might get some light by comparing the Laosian beliefs with regard to children. The Laosians think that an infant is the child, not of its parents, but of the demons; and hence they call on the demons to carry off their child within four and twenty hours after birth or else to leave it for ever. Moreover, they give the child a hideous name by way of frightening away the demon, and they sell it for a nominal price to a friend, under the impression that the demons are too honest to carry off what has been actually bought and paid for. Now if the demons had carried off a child born in a particular month, it might be thought that this gave them a special power over another child born in the same month, and that therefore special precautions were needed to prevent its dying. One of the speakers had suggested that in Persia the supposed dead man might have returned through a door in a terraced roof. In reply, Mr. Frazer said that there was evidence to show that in the case in question the entrance was made through the compluvium, an opening in the atrium or principal apartment of the house. Now as this atrium was distinctly stated by the ancients to have been originally sitting-room and kitchen in one, it is not unreasonable to infer that it represented the single apartment of the primitive house, and that the aperture in the roof (afterwards known as the compluvium) was originally the smoke-hole or chimney.

The following paper was then read by the Director:

The SCULPTURED DOLMENS of the MORBIHAN, BRITTANY.
By Rear-Admiral F. S. TREMLETT, F.R.G.S.

[WITH PLATES III AND IV.]

THE tumuli of Brittany having been so frequently described, it will be unnecessary to give in this paper a lengthened description of them, or of their contents. Several of the most interesting monuments have disappeared, but there still remain a considerable number which will probably be untouched, from the fact that below the thin coat of humus the granite rock is found, and that stone is so easily procurable that the farmers find it more economical to establish a quarry on their fields than to blast with powder the megaliths on their land. To this circumstance may be attributed the preservation of those that remain. There is, however, an exception to this, and that is when the Church requires building stone; the parishioners are then exhorted as a religious duty to obtain and bring to the church whatever material is required, which service is invariably cheerfully rendered and gratis. To this circumstance may be attributed the gap which

They count up to ten, and their numerals are—

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The first European visitors to New Ireland, and its adjacent islands, of whom we have authentic records, were Spaniards. The first expedition, headed by Mendaña de Meyra, sailed from the coast of Peru in 1567, and for some thirteen years the Spaniards with varying success continued in these waters; the only remains of their visits being the names of many islands (such as Guadalcanal, Sesga, Solomon, St. Antonia, Santa Lucia, Espirito Santo, San José, Santa Isabel, Los Reyes, Santa Cruz, and others), a few isolated words, and a marked Spanish likeness in some of the lighter-skinned natives.

Since the Spaniards, the islands have also been visited by the English in 1767, when Captain Philip discovered the Admiralty group some 150 miles further east; by the French under Deutrecasteaux in 1791, when out in search of La Perouse; and by the Americans under Captain Morrell in 1843.

Since then, and more particularly during the past twenty years, the communications with Europeans have been numerous, with fatal results to the natives. The first attraction which the islands offered was the exuberant abundance of cocoa-nuts. It may be safely said that in New Ireland and its neighbouring islands, some twenty in number, the Germans found 200,000 cocoa-nut trees in full bearing.

The annual product of each tree is worth one dollar, and it may also be safely said that the annual cost of collecting $200,000 to the Germans did not exceed £15. The barter for these cocoa-nuts consists of glass beads, poor cutlery, tobacco and pipes, cheap rum and other fire waters, with what consequences to the natives it is easy to imagine.

The Americans have kept themselves to whaling, the French to pearl-fishing and digging for bêche-de-mer, and the English of the neighbouring colonies have "recruited" the men and women for their industrial army engaged in producing sugar for the most part.

This "recruiting" has been easy on account of the peculiar power which the king or head man of an island has over the lives of the natives; he can command men and women to go wherever he pleases, and they obey without a murmur.

I suppose it may be safely inferred that the ornamenting of spears and clubs, and other missiles of war, indicates the existence

the native races of the South Sea Islands. He was quite sure that the outrages of which we had heard so much of late would be heard of no more. But the Institute must be unremitting, alike in its humane as in its scientific labours, if these and other native races are to have their share in the beneficence of the progress which so signally marks our own time.

The following paper was then read by the Author:

HINTS on VISION-TESTING.

By R. BRUDENELL CARTER, Esq., F.R.C.S.

THE circumstance that I have lately called attention to the effect of some of the conditions of civilisation upon the development of the eyeball, and upon the power of seeing, has called forth expressions of doubt with regard to the correctness of the popular belief that certain savage races are more keenly sighted than the generality of civilised men. As a matter of probability, I am disposed to think that this popular belief is well founded: first, because it rests on the testimony of writers who have been accustomed to observe with accuracy, and who have been little prone to give currency to mere marvels; secondly, because it is natural that the anatomical structure and functional excellence of the human retina, as of the retina of the lower animals, should be favourably influenced by conditions which call for a high degree of sustained activity. There may, no doubt, be many savage races among whom these conditions do not exist; but they exist in a marked manner among others, and especially in countries in which the formation of the surface and the character of the atmosphere are favourable to distant vision, and in which the natives are accustomed to employ such vision for the purposes of hunting or of war. We may reasonably hope, however, if this Institute should determine that the question requires systematic investigation, shortly to see the facts placed beyond the reach of doubt; and my object in addressing you this evening is to offer a few suggestions with regard to the lines on which the investigation should be conducted, with regard to the points which it would be specially important to determine, and with regard to certain errors which it would be equally important to avoid.

It has long been customary to express acuteness of vision in terms of the visual angle. In the diagram (p. 122), if A B represents an object of vision, A C and B C are lines drawn from its

extremities to meet at a point within the eye, and may be taken to represent the axial rays of two pencils of light which proceed

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from A and B respectively. The angle A C B is called the visual angle, and its magnitude is obviously dependent, partly upon the magnitude of the object, and partly upon its distance from the eye. The, smaller object, A' B', being nearer to the eye than the object A B, subtends an angle of the same magnitude; while the object DE, which is equal to A B but nearer, subtends the larger angle DCE. The axial rays over-cross within the eye, and proceed to impinge upon the retina. If the diagram were a correct representation of the facts, the angle a Cb, formed by the axial rays after their over-crossing, would be equal to the angle AC B, formed prior to their over-crossing, and therefore, if we knew the magnitude of the angle A CB, and the distance of the crossing point from the retina, we should know also the magnitude of the retinal image. Hence, within certain limits, the magnitude of the retinal image depends upon the magnitude of the visual angle, and this again upon the size and distance of the object; and the commonly received view is that the limit of visibility depends upon the absolute size of the individual elements of which the perceptive layer of the retina is composed. The most sensitive of these elements, the cones of the retina, have a diameter of about four-thousandths of a millimetre across the inner portion, and of about one-thousandth of a millimetre across the outer portion; and it has been assumed that a retinal image does not become an object of sense perception unless it is large enough to cover the surface of a single element. This condition is fulfilled, apparently, in a well-formed eye, by the image of an object which subtends a visual angle of one minute, or even a little less, an angle of fifty seconds being the smallest under which the distinctness of two points is recorded to have been seen. This high acuteness of vision has only been attained under very favourable conditions of illumination; and, for clinical purposes, it has been found necessary to adopt an arbitrary and much lower standard.

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