When any one of the following tables has been given in the past to an extent useful at the present time, it will be found by the computer that the necessary volume is only with difficulty accessible and hardly ever to be purchased. That these tables are obviously useful is perhaps all that need be said in justification of their more extended computation.

Although a few papers have been published a number of years ago on the genus Ephedra, the authors have treated the subject mainly from a systematic standpoint. Thus, while the characters of the floral organs have been carefully examined and described, the structure and character of the vegetative organs have only received passing reference. It is proposed in the following notes to undertake the study of the histology of the vegetative organs, and thereafter to ascertain how far this knowledge applies to the determination of species. The following notes deal with the histology of the primary stem.

In the following Paper, it is proposed to illustrate more fully the hint explanatory of certain atmospheric colours, given in a notice of the remarkable red hue of condensing steam, communicated on the 21st January. Since that time, I have examined with care the principal authors who have adverted to the subject of the colour of the sky generally, and of the redness of sunset in particular; and since, in the course of that research, I have found much to confirm, and little to modify, the view which I have already taken of the subject, I hope that the present Paper may be considered as a fit appendix to my former experimental notice. It will be recollected that in it I stated the singular fact, that steam does not pass at once from the state of invisible pellucid vapour to that of a misty white cloud, such as issues from the spout of a tea-kettle; but that an intermediate stage occurs, in which it is coloured, even very highly, giving to transmitted light a hue varying from tawny yellow up to intense smoke-red. I then observed, that, since this phenomenon does not require steam of high tension for its production, it is very probable that the tints of sunset and of artificial lights seen through certain fogs, may be owing to the absorptive action of watery vapour in this critical condition.

The usual methods of obtaining pure phosphoric acid by the oxidation, with nitric acid, or by combustion, of pure phosphorus, are well known; but, although they yield a pure product, yet, as the phosphorus must be prepared from phosphoric acid, it is obvious that we shall derive a great advantage from any method of purifying easily and cheaply the phosphoric acid from bones, instead of first reducing it to phosphorus, and then re-oxidizing it. In practice, phosphorus is made from the superphosphate of lime, and it is from the same salt that phosphoric acid may be most economically prepared.

[Since this second instalment of my paper was read to the Society my attention has been called to a remarkable investigation by Hertz; in which the circumstances of collision of two elastic spheres are fully worked out, under the special limitations that both are smooth, and that their deformations are exceedingly small. This forms a mere episode in the paper, which is devoted mainly to the statical form of the problem of deformation; as, for instance, the case of the ordinary apparatus for the production of Newton's rings. But it contains a definite numerical result; giving for the duration of impact between two iron spheres of 50mm diameter, which encounter one another directly with a relative speed of 10mm per second, the value 0s·00038. This seems to be the earliest reckoning of the time of collision. The experimental verification of Hertz' formulæ was undertaken with success by Schneebeli, who obtained results in close accordance with them. His mode of measuring the duration of impact was defective, though ingenious.

That the stelar problem considered in this paper may be more clearly visualised, it will be well to divest of purely theoretical considerations the facts of stelar structure already known for Platyzoma, and to summarise such structural features as bear on the subject in hand.

In the first account of Platyzoma given by Robert Brown in 1810 (l), the habit of the stem and heterophyllic leaves, and the general form and position of the sporangia, were alone described. But in 1832 (2) a rough analysis of the structure of the stem was added, and the tubular nature of its stele was recognised. No material contribution to the knowledge of the stelar structure was made until 1893 (3), when Dr Poirault described the histology of the stele as shown by a small fragment of stem. In this material there was a sclerotic pith completely surrounded by an endodermis, outside which lay a zone of parenchyma surrounded by a broad ring of parenchymatous xylem. At the periphery of the xylem there was a narrow zone of phloëm surrounded by a large-celled pericycle and an outer endodermis. Neither leaf-gaps nor perforations were found in the stele, and accordingly the complete isolation of the pith from the cortex was recognised.

We have examined the sample of spirits, which was sent by Dr Hunter of York to the Royal Society, and we have read the account of the experiment on the sermentation and distillation of carrots by which the said spirit was produced. The experiment was made by Mr Thomas Hornby, druggist in York, with one ton and eight stone of carrots, which, after being exposed to the air a few days to dry, weighed 160 stone, and measured 42 bushels; they were washed, topped and tailed, by which they lost in weight 11 stone, and in measure seven bushels; being then cut, they were boiled with the proportion of 24 gallons of water to one third of the above quantity of carrots, until the whole was reduced to a tender pulp, which was done in three hours boiling.

From the point of view of its function, a nerve fibre is a conductor of nervous impulses, and as such is the path of communication between two structures, the one situated in the central nervous system, and the other in the periphery. In the mixed nerve, such as the sciatic, the nerve fibres are distinguished as afferent or as efferent, according as they conduct impulses originating at the periphery, and received by a cell in the central nervous system, or vice versâ. It has long since been shown that nerve fibres are capable of conducting impulses in either direction, but normally, from their anatomical connections, the individual nerve fibres are conductors for impulses only in the one or in the other direction. This is proved by the Wallerian method of investigation, as on severance of the posterior spinal root distal to the ganglion only certain fibres degenerate and the conductivity of the nerve only for afferent impulses is lost, while the severance of the anterior root is followed by the degeneration of the remainder with loss of functions depending on efferent impulses.

Topography.—The extent of the area dealt with in this paper and the position in that area of the various igneous masses under consideration are indicated in the sketch-map (fig. 1). On both sides of the Firth of Forth the ground considered consists of low-lying, undulating, arable land intersected by numerous steep ridges. These ridges, which form conspicuous features in the landscape, indicate the outcrops of doleritic sills. They are often tree-clad, and frequently show lines of cliffs on one side. The ridge known as Mons Hill attains a height of 387 ft., which is the maximum for the district. Other conspicuous ridges occur at Craigie, Dundas, West Craigs, Lindsay's Craigs, and north of the Forth at Braefoot and Aberdour. Where the larger igneous masses reach the shore they tend to form rocky promontories, as, for instance, at Hound Point, Snab Point, and Braefoot. Rocky islets a short distance off shore may also be formed, a good example of which is seen at Hound Point.

The notice which, at the suggestion of Dr Brewster, is now to be laid before the Society, respecting a remarkable shower of hail which lately fell in Orkney, has been drawn up partly from conversations with Richard Caithness, a plain but intelligent country man, who possesses a small farm at Hunday in the island of Stronsa, and whose property suffered severely from the shower; and partly from subsequent correspondence with the Reverend William Taylor of Stronsa, whose house lay in the track of the cloud, and with Mr Robert Lindsay, Student of Divinity, who had an opportunity of witnessing the effects of the hail at Lopness, on the neighbouring island of Sanda, when the shower was nearly exhausted. They agree in all important particulars; but even at the risk of some repetition, their own words shall, as often as possible, be employed.

The morning of the 24th of July 1818, was, in Orkney, clear and warm, with a slight air of wind at due south.

About ten months ago, I had the honour of communicating to the Royal Society, a description of a new instrument for ascertaining the Magnetic Dip. Having made very considerable improvements in the apparatus, by means of which some curious results on the magnetic laws, especially those that relate to the production and annihilation of magnetism in iron, have been obtained,—I now beg leave to submit to the Society a drawing and description of my improved instrument, together with an outline of some of the most interesting experiments made with it. Many of the results appear to me to be new; if so, their importance will be my excuse for repeating some parts of the description given in the former paper. It has been long known that iron might be rendered magnetical by percussion; but I am not aware that the precise effect of position has ever been suggested, I remain, &c.

A little more than a year ago, I was led to conclude that the primitive hypoblast in pelagic Teleostean ova was derived mainly from the unsegmented protoplasm forming the floor of the segmentation cavity. In this respect my results were mainly in harmony with the researches of Lereboullet (21), Kupffer (18 and 19), Klein (16), Van Bambeke (3), and others, but opposed to the more recent investigations of Henneguy (10), Hoffmann (14), Kingsley and Conn. (15), Ryder (24), Agassiz and Whitman (1), and Cunningham (8.) At that time I adopted Agassiz and Whitman's name of periblast for the subgerminal layer containing free nuclei, though I differed from those authors in my idea of the mode of origin of the nuclei. As, however, I regard the tissues derived from this layer as belonging chiefly to the parablastic group of His and Waldeyer, I propose to return for the present to the older name of parablast. I was not enabled to trace the origin of this layer in my earlier investigations, and thus failed to grasp its significance. More recently I have had an opportunity of studying the development of several other types, particularly the herring and cod. In the herring the germinal mound is not formed until after fertilisation. Partly owing to this circumstance, and partly also to the early period at which the assimilation of yolk commences, the eggs of the herring are particularly well suited for a study of the parablast question.

Every mineralogist is conversant with some of the facts relative to the subject of this paper. Some of the observations enumerated, are comparatively new, as the attention of naturalists has been only of late more particularly directed towards these facts. Others, which I have had an opportunity of collecting myself, I trust will not be considered uninteresting, as they tend materially to rectify certain ideas connected with the determination of the mineralogical species, the most important branch of natural-historical research.

The following observations may serve to illustrate and confirm the opinion now very generally adopted by Anatomists and Physicians, That an affection of one hemisphere of the brain, whether from internal disease or external accident, produces its morbid symptoms on the opposite side of the body.

The celebrated Bouguer was the first who discovered the important fact, that the eye can detect a very small difference between two similar illuminated surfaces, when viewed at the same moment,—the only principle which has yet been applied with any degree of success, in determining the relative illuminating powers of artificial flames. The following is perhaps the most commodious application of this principle, to determine the relative illuminating powers of different artificial lights, particularly of coal and oil gas. The instrument, or photometer, which I employ for this purpose, is extremely simple. It consists of a rectangular box, about an inch and a half, or two inches square, open at both ends, and blackened within for the purpose of absorbing the stray-light.

In the second volume of the Asiatic Researches, an extract is given from the Surya Siddhanta, the ancient book which has been long, though obscurely, pointed out as the source of the astronomical knowledge of the Brahmins. The Surya Siddhanta is in the Sanscrit language: It is one of the Sastras, or inspired writings of the Hindoos, and is called the Jyotish, or Astronomical, Sastra. It professes, as we learn from Mr Davis, the ingenious translator, to be a revelation from heaven, communicated to Meya, a man of great fanctity, about four millions of years ago, toward the close of the Satya Jug, or of the Golden Age of the Indian mythologists; a period at which man is said to have been incomparably better than he is at present; when his stature exceeded twenty-one cubits, and his life extended to ten thousand years.

Of these gigantic thermometers, with their bottle-sized bulbs, their long capillary intermediate tubes, and their upper enlarged bores for scale-reading purposes, an account of their construction and being placed in position for observation on June 26, 1879, is to be found in Part II. Vol. XXIX. of the Transactions of the Royal Society, Edinburgh, for 1879–80, and it is only proposed in the present place to give an account of their performances since that time.

The Paper which I have the honour of presenting to the Society, is drawn up from letters written by Captain Hall to some of his friends in this country, after a visit made to the Cape of Good Hope, and an excursion to the Table Mountain, in July last. I have given the description, as much as possible, in his own words, and have only connected parts, which, from the nature of the communications, were necessarily disjoined from one another. One of the letters being written to myself, and containing a general view of the whole, has been my guide for arranging the rest.