issue of the Encyclopædia Britannica, no light is thrown on the subject. The horns have been regarded as weapons, and to this view I myself incline, though no one seems to have seen the Beetles using them in an encounter. The males of the Stag-beetles certainly fight with much ferocity. There is something in the caliper-like shape of the horns that seems well adapted for grasping another Beetle of the same size and kind round the body; and the hair on the underside of the upper horn would contribute to a firmer hold. The large horns are confined to the males, and this seems to be the case in all the Lamellicorn Beetles, with the exception of a single genus. Similarly in Mammals, the males alone have large horns, with the exception of the Reindeer, and in the case of domesticated animals. Mr. Darwin, whose opinion is always most valuable, regards the horns of the Dynastide as simply ornamental appendages. Here, then, is one of the most conspicuous and best and longest known insects (I can remember seeing A. Hercules at least fifty years ago) with its life-history still in the dark, whilst collectors have been at the pains of naming and cataloguing more that 70,000 species of the same Order. Mr. Darwin's suggestion opens the wide question of aesthetic capacities in Beetles. No Order of living things is more marvellously or variously beautified. We have no jewellery which can surpass the elytra of some of the smaller kinds. A rich reward of interesting biological results may be gained by any observer who will properly investigate the relations between the ornaments and the life-habits of the Coleoptera.'

Dr. BROWN then referred to "Some Specimens of Silicified Wood from the Argo Collection," and said:

* Since the foregoing communication was made, a photograph of the male specimen has been taken, and sent to Dr. Murie, Secretary to the Linnean Society, by whose kindness it has been identified as Dynastes (Augosoma) Nepturus, Schonherr. It is probably a native of Guiana.-H. H. H.

Among the specimens brought from Antigua by the Rev. H. H. Higgins, and deposited, with the rest of the Argo collection, in the Free Public Library and Museum, were several examples of petrified or fossil wood. I received fragments of four for analysis, labelled' as in the table; they yielded the following results, expressed in parts per 100. I append also the results of analysis of a large specimen of silicified palm, now in the Museum, brought from Lota, near Valparaiso, in 1869, and presented by Captain West.

Mr. R. C. JOHNSON, F.R.A.S., read the following:

DESCRIPTION OF OBSERVATORY AT HIGHER

BEBINGTON, CHESHIRE.

THE design of an observatory is to afford to the telescope and its accessories adequate protection from the weather, while at the same time it permits a clear view of all parts of the heavens.

Perhaps the most important consideration in the construction of any observatory is that connected with the rapid equalisation of internal and external temperatures; because, if there is more than a slight difference between the two,

currents of air of unequal density are set in motion, which are prejudicial to definition (even in the use of small instruments), and absolutely fatal to the performance of large ones, especially of reflectors, a form of telescope which has, during the last ten years, again come extensively into use.

The definition of refractors is not so liable to disturbance by neglect in this respect, probably because the object-glass is so near to the roof of the building that there is a much shorter column of air over it than there is over the speculum of a reflecting telescope.

This observatory is of two storeys; the lower one (which is not necessary, but is always convenient) has been made for the purpose of raising the telescope sufficiently above surrounding objects, and is utilised for a laboratory and photographic room; by having the telescope so far above the ground the observing room is entirely free from damp.

The pier, which supports the telescope, rises from a firm foundation, and is carried through this room without touching either of the floors, so as to avoid the communication of

tremors, caused by persons moving inside the building, or by wind on the outside of it. The pier is hollow in the centre, in the usual way, and is open down part of one side, so that a well-ventilated space is allowed for the fall of the weight of the driving-clock.

The upper or equatorial room, which is of the form known as the drum dome, is circular, of 13 feet 6 inches in diameter, and is 10 feet high, and, with the exception of the lowest part, 1 foot in height, which is a continuation of the wall of the room below, consists of a timber frame-work covered with corrugated zinc.*

The drum rotates on twelve wheels, which are of 5 inches in diameter, and are firmly bolted to the top of the wall, and it is provided with two large openings by which every part of the sky can be reached. One of these openings is in the roof, and is 9 feet by 3 feet 6 inches clear aperture, and the other, extending nearly the height of the dome, is 8 feet by 3 feet 6 inches.

It will be apparent from this description that care has been taken to carry out, as far as possible, the principle alluded to at the commencement of this paper, viz., the maintenance of equilibrium between the inside and outside temperatures.

By covering the frame of the building externally with sheet metal, as night approaches the heat which it has acquired during the day will be rapidly radiated; and by having such large openings the temperature of the whole building, and the contained air, can be brought in a few minutes to within 1° Fahr. of that of the external air. This

Technically known as "Italian zinc roofing. The zinc is manufactured in sheets, 8 feet by 3 feet, each having two ridges or corrugations running lengthwise, which reduce the width of the sheet to 24 feet, but at the same time add so greatly to its strength, that it is used for roofing without other supports than light rafters, set 15 inches apart, so as to fit into the corrugations. Many acres of dock-sheds, on both sides of the Mersey, are covered in this way.

result could have perhaps been even better attained by a construction wholly of iron, but from the experience of a previous observatory of that material, in which much annoyance was found in doing those little alterations and additions which are constantly required, the present mode was chosen instead, as being nearly equal theoretically, and much more convenient in practice; besides, it must not be forgotten that, however perfect in this respect the building itself may be, a large telescope and its mounting may absorb a quantity of heat, that cannot be immediately radiated.

The openings of the dome are closed by two movable shutters. The roof shutter, which from being so large would be difficult to move in other ways, runs on six small flanged wheels on iron rails, and these rails are carried on supports which extend beyond the building just so far as to allow the shutter to completely clear the opening in the roof, which is four feet longer than the semi-diameter of the dome-a plan which I find to answer exceedingly well, for the shutter is remarkably easy to open and close, and at the same time weather-tight.

A door which opens outwards on hinges closes the side aperture.

If these openings were made in the ordinary way, continuous, it will be perceived that the strength of the structure must be interfered with, for it would be necessary to leave a space of 17 feet by 3 feet 6 inches unsupported by any ties, and a defect known as sagging would be introduced. It is easily seen that if this should take place to only a very slight extent it would derange the fitting of the top shutter; so to obviate this, the side shutter is made to open, not in a line with the horizontal one, but at a point removed from it by about one-twelfth of the circumference; and by this the strength of the building can be made scarcely less than if only one of these openings had been required.