This occurrence, following an unusual fall of rain in January, took place in May, June, and July. The ordinary amount of rain in these months is,—taking the average of the last eleven years,—at Lesketh How, Ambleside, 12·36 inches; during the months in question, at the same place, it was only 4·54 inches.

The author shows, that oil of cajeput is a mixture of an oil boiling about 175° Cent., and one or more oils of higher boiling point. In the present paper he investigates the first of those substances. When purified by repeated distillation, it is a colourless, limpid fluid, which by analysis and determination of its vapour density, is shown to have the formula C20 H16 + 2HO. When treated with anhydrous phosphoric acid, it is decomposed, and yields a mixture of three different hydrocarbons, to which the author gives the names of Cajputene, Isocajputene, and Metacajputene. The two former, though differing in properties, have both the formula C20 H16. The last, which is a very heavy oil, with a lemon yellow colour and brilliant fluorescence, is C40 H32.

At the recommendation of Dr Anderson, Glasgow University, I have re-examined the oil which Plantamour obtained by acting on citric acid with chlorine. Owing to the slowness with which it is formed, its complete investigation is somewhat lengthened, and the following results are all I have as yet obtained. A considerable part of the work has been done in the Glasgow College Laboratory.

Plantamour found that when a strong solution of citric acid was exposed to the action of chlorine in the sunshine, a heavy oil appeared on the surface of the liquid, gathering in drops and sinking to the bottom. He describes the properties of this oil, and ascribes to it the formula C8 Cl8 O3.

A recent panoramic topographical view of the interesting region of Kashmir having been just communicated to me by my friend, Mr Roger Montgomerie, Advocate, I have found it so remarkably well executed, in its almost photographic representation of natural features of hill and plain, that I have obtained his leave to present it to the Royal Society, accompanying the presentation with the following few particulars, abstracted from MS. reports.

The author gave an account of the cultivation of plants of Asafœtida in the Edinburgh Botanic Garden since the year 1842, and of the flowering and fruiting of specimens in 1858 and 1859. He then described the characters of the plant (Narthex Asafœtida of Falconer), and illustrated his communication by specimens of the plant, by photographs, and by drawings from the accurate pencil of Dr Greville.

The present paper was undertaken at the suggestion of the late Professor George Wilson, as forming an interesting inquiry, both to the antiquarian and the chemist, and as a sequel to the paper upon old Scotch glass, communicated by me to this Society some time since.

The investigation had for its object,—

1st, To ascertain the exact composition of the glassy surfaces of the various specimens.

2d, The composition of the rocks upon which the glass was formed.

3d, To account for the formation of such glass by the information afforded by the first two inquiries.

The principle followed in the reductions which form the subject of this communication may be briefly stated thus:—

The varying temperature during a year, shown by any one of the underground thermometers on an average for a series of years, is expressed by the ordinary method in a trigonometrical series of terms representing simple harmonic variations,—the first having a year for its period, the second a half year, the third a third part of a year, and so on. The yearly term of the series is dealt with separately for the thermometers at the different depths, the half yearly term also separately, and so on, each term being treated as if the simple periodic variation which it represents were the sole variation experienced.

In this paper the same general method of reduction as that of Professor Thomson, explained in the preceding paper, is followed. The numerical labour is, however, much diminished by using the monthly means given in the observatory report as data for twelve equations of condition, instead of the methods by which Professor Forbes had obtained data for twelve, and Professor Thomson for thirty-two equations of condition. The method adopted in the present communication, although not susceptible of such minute accuracy as the more elaborate methods referred to, seems to be as accurate as is necessary for a fair representation of the phenomena, and has a great advantage in point of simplicity and ease of working.

These contributions are part of the results of the author's visit to Iceland in June 1860, and will be found embodied in his Paper “On the Eruption, in May 1860, of the Kötlugjá Volcano, Iceland,” in the “Edinburgh New Philosophical Journal” for January 1861, page 6, with a map (Plate II.), “Illustrative of the Physical Geography of that part of the South of Iceland in which Kötlugjá is situated.”

The object of this paper was to determine whether the pediculi infesting the different races of man were of the same or of distinct species, and thereby to ascertain whether any inference could be drawn therefrom, bearing upon the disputed question of the unity of the human species.

It is well known that hydrated sulphuric acid loses sulphuric anhydrid on heating, and that its specific gravity decreases in consequence. It is of some practical importance to know the exact circumstances under which this takes place, and the following experiments may prove useful in this respect. Sometimes, in distilling and subsequently evaporating sulphuric acid, I obtained a hydrate of sp. gr. 1·848, and at other times not exceeding 1·842.

The experiment referred to was performed in 1823 by Ampère in the presence of Mr A. De la Rive. It is intended to show that if one portion of a rectilinear conductor is made moveable, it will be repelled from the portions which form its continuation. The arrangement employed was a copper wire-float in a double trough of mercury, which cannot easily be explained without a figure.

This experiment, though quoted by most writers on electricity, is understood to be one not easily repeated. Indeed, the author has not found an indication of its ever having been repeated with success. The author conceiving that perhaps this repulsion described by Ampère might assist in explaining the vibrations of rocking bodies through which an electrical current passes (as described in a communication by him to this Society in January 1859), devised another, and, as he conceives, a more delicate method of testing the supposed repulsion of a rectilinear current on itself.

These notes, it is stated by the author, were made at different times and places, as opportunity favoured, and are offered as a contribution to a difficult branch of Ichthyology.

The generative organs of nine different species are described, with more or less minuteness of detail. The species are Squalus squatina, S. galeus, S. acanthias, S. carcharias, S. centrina, S. canicula, Scyllium melanostomum, Raia aquila, and R. oxyrhynchus.

The authors refer to Regnault's experiments, which have shown that aqueous vapour in the atmosphere has the same vapour density at ordinary temperatures as aqueous vapour above 100° C.; and they bring forward fresh experiments upon alcohol and ether to show that when mixed with hydrogen these vapors preserve their normal density at 20° or 30° C. below the boiling points of the liquids, and infer generally that vapours, when partially saturating a permanent gas, retain their normal densities at low temperatures.

On the 26th of December last, about half-past 11 A.M., a light snow shower fell in Edinburgh, and lasted about half an hour. The air was at the time still, and the sky overcast with a thin haze, while the thermometer stood at many degrees below the freezing point. The appearance of the snow was very remarkable. It fell in loose open flakes, and lay upon the surrounding objects in little masses like tufts of exquisitely white, soft and light down.

The bifilar magnetometer has been employed in all the magnetical observations, with an exception or two; its theory has been stated generally, but no careful examination of the errors of the instrument, as deduced from experience, has been published. The author has attempted to supply this deficiency.

In the theory of the instrument, the proper elasticity of the wires has been neglected, as of little importance. The author shows that the wires receive a twist in the adjustment, which puts the upper suspension-points into a different plane from the lower ones; that the force so produced enters into the equation of equilibrium in a marked manner. The theoretical conclusion is verified by experiments on the torsion force of the wires.

The conclusions of this paper are derived from observations made at Makerstoun in Scotland; Toronto, Canada; Trevandrum, Travancore, and Singapore, East Indies; St Helena, the Cape of Good Hope, Hobarton, Van Dieman's Island, &c. The author has corrected and discussed all the observations published made in the colonial observatories.

The observations have been found affected by different errors, and frequently the series have been broken. An attempt has been made to correct these series; and, in general, to render the series as near the truth as possible. The grounds for all these corrections are given in an appendix.

If we suspend a weight by two wires, and turn the weight suspended from its position of repose through an angle υ by means of any force, the wires will no longer be vertical, and the weight will be lifted from its lowest position by a gravity equal to l sin i tan i where l is the length of a wire and i is the small angle which it makes with the vertical.