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.

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 examining the changes which light undergoes during its passage through transparent bodies, we not only receive information respecting the properties of that mysterious agent; but we are in some measure made acquainted with the composition of the substances themselves, and with the manner in which their ingredients are combined. The optical phenomena, therefore, which bodies exhibit in their action upon light, are so many tests, to which the philosopher may have recourse, either in supplying the place of chemical analysis, or in correcting and modifying its results. A difference in the optical properties of two bodies, is generally an infallible indication of a difference in their elementary principles; and whatever confidence we may place in the skill of the chemist, or in the accuracy of his methods, the mind can never rest satisfied with the results of an analysis which is directly opposed by optical phenomena.

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.

It is well known that no satisfactory demonstration has ever been given of Fermat's celebrated theorem, which asserts that the equation an = bn + cn is impossible, if a, b, c, are whole numbers, and n is any whole number greater than 2. In Legendre's Théorie des Nombres, he demonstrates the cases of n = 3, n = 4, and n = 5, the latter only in his Second Supplement. In Crelle's Mathematical Journal, ix. 390, M. Dirichlet, a mathematician of Berlin, has demonstrated the case of n = 14, but I am not aware whether his demonstration is considered successful. Legendre informs us (Second Supplement, p. 3) that the Academy of Sciences, with the view of doing honour to the memory of Fermat, proposed, as the subject of one of its mathematical prizes, the demonstration of this theorem; but the Concourse, though prolonged beyond the usual term, produced no result.

All taxa of Orthoptera known from the latest Eocene deposits of the Isle of Wight are redescribed or discussed, based on the study of their type material. The following new taxa are described: Ontogryllus gen. nov., O. rossi sp. nov. (type species), Achetomorpha gen. nov., A. irregularis sp. nov. (type species), and Proeneopterotrypus gen. nov. The latter genus is here proposed for Pteroplistes danicus Rust, described from the Palaeocene/Eocene of Denmark, as this find is important for understanding the systematic position of the genus Eneopterotrypus Zeuner. Remarks about the taxonomy of the taxa studied, age of these deposits, and ecology are given.

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.

While the external infiltration of water has been identified from modern geothermal and/or fossil hydrothermal systems through stable isotopes, the physicochemical boundary conditions like the initial oxygen isotopes of water $( {{\rm \delta }^{ 18}{\rm O}_{\rm W}^{\rm i} } ) $ and rock as well as alteration temperature were implicitly presumed or empirically estimated by the conventional forward modelling. In terms of a novel procedure proposed to deal with partial re-equilibration of oxygen isotopes between constituent minerals and water, the externally infiltrated meteoric and magmatic water are theoretically inverted from the early Cretaceous post-collisional granitoid and intruded Triassic gneissic country rock across the Dabie orogen in central-eastern China. The meteoric water with a $ {{\rm \delta }^{ 18}{\rm O}_{\rm W}^{\rm i} } $ value of −11.01 ‰ was externally infiltrated with a granitoid and thermodynamically re-equilibrated with rock-forming minerals at 140°C with a minimum water/rock (W/R)o ratio around 1.10 for an open system. The lifetime of this meteoric hydrothermal system is kinetically constrained less than 0.7 million years (Myr) via modelling of surface reaction oxygen exchange. A gneissic country rock, however, was externally infiltrated by a magmatic water with $ {{\rm \delta }^{ 18}{\rm O}_{\rm W}^{\rm i} } $ value of 4.21 ‰ at 340°C with a (W/R)o ratio of 1.23, and this magmatic hydrothermal system could last no more than 12 thousand years (Kyr) to rapidly re-equilibrate with rock-forming minerals. Nevertheless, the external infiltration of water can be theoretically inverted with oxygen isotopes of re-equilibrated rock-forming minerals, and the ancient hydrothermal systems driven by magmatism or metamorphism within continental orogens worldwide can be reliably quantified.

[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.

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.

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 Cnoc Rhaonastil dolerite boss on Islay, NW Scotland represents a body of alkali-olivine basalt magma which differentiated at low pressure and in situ, from dolerite through teschenite to minor nepheline-syenite. The syenites occur as isolated pods and pegmatitic schlieren within the leucodolerite, and have an exotic mineralogy including Zr-aegirine, Zr-arfvedsonite, Ca-catapleiite, zirconolite and aenigmatite. Fluor-apatite occurs as an accessory phase in the dolerite, but becomes more abundant within the teschenite and syenites. Total REE contents within apatites in the dolerites are typically low (σREE = 0·57–3·21 wt.% oxide), the highest REE contents occurring in irregular, deuterically altered rims and internal patches. The REE-enriched rims also have slightly elevated SiO2 contents at 0·81–0·95 wt.%, suggesting that the substitution scheme Ca2++P5+ ⇔ REE3++Si4+ was operating. These apatites have up to 0·08 wt.% Cl and 3·7 wt.% F, with most being almost pure end-member fluor-apatite. The majority of the teschenite apatites show the least REE-enrichment (σREE = 0·27–0·45 wt.%), coupled with low Na (<0·12 wt.%) and low SiO2 (<0·39 wt.%) contents. However, within the syenites two distinct populations of apatite exist. The first, most common, variety consists of unzoned, low-REE apatites (max. 3·1 wt.% σREE, again in irregular rims and patches), whereas the second variety is often complexly zoned, and has variably enriched zones up to a maximum σREE content of 42 wt.%; this is by far the most REE-enriched natural fluor-apatite so far reported from the British Isles. The REE-enriched zones are often less than 3 μm wide, and have Na content up to 5·4 wt.% Na2O, implying that the substitution scheme Na+ + REE3+⇔2Ca2+ dominated over the more typical scheme involving Si4+ which operated in the dolerites and teschenite. Other zones are either variably enriched in Y (up 2·1 wt.% Y2O3) or Th (up to 0·85 wt.% ThO2). However, there is no correlation between Y and REE contents, suggesting that crystallographic factors were involved in apatite Y and REE partitioning. The REE-rich apatites have very low Cl content (<0·04 wt.%), but high F concentrations (<2·8 wt.%). It is believed that these strongly enriched apatites crystallised under disequilibrium conditions from isolated, variably REE-enriched domains, within the fluid-rich residual syenitic magma. These domains may have been generated by the prior crystallisation of monazite, Ca-catapleiite or zirconolite, which can be found as small inclusions within albite and interstitial analcime. The dynamic process of slumping of the denser teschenite back into the leucodolerite crystal mush is believed to have played an important role in the release of deuteric fluids and the concentration of residual magmas.

When preparing to make a night journey over one of the plains of South Africa, in the month of June 1843, a friend called my attention to the peculiar appearance of the sky in the west, as offering a very decided proof, “agreeably with theory,” that there was no “Solar atmosphere” to be seen at that season of the year.

On looking in the direction mentioned, the last portion of the twilight was just visible, and forming a peculiarly level line above the place where the sun had set, for an extent in azimuth, of perhaps 40°, and at a height of about 5°. All the gorgeous colours which had attended the setting of the sun had long since vanished, and there only remained sufficient light within the flattened arc described, to make the space included between it and the horizon appear light blue, while all the rest of the sky had attained a deeper colour, nay was almost black, and thickly spangled with small as well as large stars.

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.

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.