In an observatory where, as in that of the Calton Hill, the principal object of pursuit is the determination of the exact places of the fixed stars, and the investigation of those exceedingly slow secular variations, which require many thousands of years to run their cycle,—the stability of the instruments, as a necessary element to the accuracy of the observations, becomes of the extremest importance.

To secure this quality much invention and no little ingenuity have been employed, but not yet with perfect success; for invariably the more accuracy we demand, the more insuperable difficulties appear to arise. Even nature at last appears to be taxed beyond her powers, for we find when we have passed beyond a certain degree of magnifying power, that there are no bodies absolutely stiff and rigid—none constantly of the same dimensions; but all are expanding and contracting, and giving and limiting with every change of temperature or application of small accidental pressures.

Following up his researches on pyromeconic acid, read before this Society in 1852, the author described a method which he had recently discovered, through his experiments on iodo-pyromeconic acid, of generally obtaining iodine substitution for hydrogen compounds.

The electric time-ball, erected on the Calton Hill last October by the Government, and placed under the author's charge, has now been at work for five months. But the work has necessarily been of an experimental or tentative character; for before the accuracy of the signals could be guaranteed, it was necessary to have experience of the machinery in all weathers; and, moreover, the present strength of the Observatory establishment, and the nature of pre-existing occupations, prevented the experiments being made every day.

In this paper it is shown, that by the sun's heat there is an emission of mechanical energy from the solar system, amounting in about 100 years to as much as the whole energy of the motions of all the planets. The principal object of the paper is to investigate the source from which this vast development of energy is drawn. It is argued, that either a store of primitive heat must be drawn upon, or heat must be generated by chemical action (combustion), or heat must be generated by other forces than those of chemical action, that is, by forces of moving masses. Any store of primitive heat that can be drawn upon in solar radiation, must be entirely within the sun.

This paper contains some details of a continued investigation, of which the first results were communicated to the Chemical Society of London last year. It was then shown that new bases are produced by the action of iodide of methyl and of ethyl upon morphia and codeine, which are closely analogous with the ammonium bases of Hofmann, so that these alkaloids should rank among nitryle bases. The fact was also pointed out, that although one of the new salts produced had precisely the centesimal composition of the corresponding compound of codeine, the base of the artificial product was widely different from this alkaloid; and the conclusion was drawn that the primary molecules of these natural formations are of so peculiar a constitution, that chemists are not yet in the possession of means of imitating the process of their construction; for even the attempt to convert morphia into codeine fails, though the addition of the requisite amount of carbon and hydrogen to the former is readily effected.

The velocity of light being 192,000 miles per second, and the mechanical value of sunlight incident perpendicularly on a square mile at the earth's distance being 83 × 5280 × 5280 foot pounds; the mechanical value of all the energy potential and actual, kept up in the space of a cubic mile by sunlight crossing it, is = 1200 ft. lbs. at the earth's distance. Similarly the mechanical value of a cubic mile of sunlight near the sun is found to be 1200 × 46,000=55,000,000 foot pounds.

In this communication the mode of experimenting was described by which the experimental results quoted in the theoretical paper were obtained; and the principal parts of the special apparatus which had been constructed and used in the investigation, were laid before the Royal Society.

In this paper the Mechanical Theory of Thermo-electric Currents in linear conductors of non-crystalline substance, first communicated to the Royal Society December 15, 1851, is extended to solids of any form and of crystalilne substance.

It is first proved, that if a solid be such that bars cut from it in different directions have different thermo-electric powers relatively to one another, or to other linear conductors, forming part of a circuit, there must, for every bar cut from it, except in certain particular directions (principal thermo-electric axes), be a new thermo-electric quality, of a kind quite distinct from any hitherto known; giving rise to a reciprocal thermo-dynamic action, which consists of a difference in temperature at the sides of the bar causing a current to flow longitudinally, when the two ends, being at the same temperature, are connected by a uniformly heated conductor; and a current through the bar causing an absorption and evolution of heat at its two sides, when these are kept at the same temperature.

The author directed attention to the following list of species, which, although imperfect, exhibits great variety in the forms, shewing the Medway to be very fertile in these organisms.

Some of the species in this list have been described as new to Britain by Mr Roper, in a late paper published in the Microscopical Journal. The Coscinodiscus, not named, seems from the description to be the same with that found at the mouth of the Thames, and is an exceedingly beautiful disc. The four species of Actinoptychus are those described by Ehrenberg, and are new British species. They exhibit the strong siliceous cellular tissue underneath the moniliform structure of the surface, as in Actinocyclus.

This paper is in continuation of one printed in vol. XV. of the Royal Society's Transactions. The object of it is to test the correctness of the method of observation, and of calculating the results, there proposed; and to compare both with those of more recent authors, particularly of M. Regnault of Paris, and of Dr Joseph Hooker.

The author finds the results of his subsequent observations in 1846 in the Alps, up to heights considerably above 10,000 feet, to agree well with those previously published, made in 1842. They combine in showing a sensibly uniform fall of the boiling point at the rate of 1° for 543 feet of ascent, which differs only 6 feet (in defect) from his previous determination.

These observations are given in seven sections:—

In the 1st, the author treats of the air-bladder of these fish, and the contained air, which he found, in every instance that he examined it, to be chiefly azote.

In the 2d, he points out a mistake he had fallen into in the instance of the female fish, as regards its abdominal aperture, which, in a former paper he had described as open only for the passage of the ova; on further examination made on the larger species, he has ascertained, that though virtually closed, except during the spawning time, it is not absolutely, either by a membrane or adhesion.

The author referred, in the first instance, to the character of stratification, illustrating the subject by specimens displaying the intermittent character of the carrying agent and of the supply of material, pointing out the Hailes Quarry as furnishing the best example in the neighbourhood of the repetitions of strata. He then stated the views of Townson, Whitehurst, and Jameson, as to the relation of the trap rocks to the sandstones with which they are interstratified. He then took notice of a statement in vol. xiii. of the Transactions of the Society, recorded by Lord Greenock, that Edinburgh may be considered as a valley of elevation, the trap rocks in the neighbourhood dipping outwards as from a common centre.

The general identity, in idea and design, of the ancient monuments of southern and western Europe with those of Hindostan, was shown and illustrated by drawings of cairns, barrows, kist-vaens, cromlechs, circles of stones, and obelisks, or, as they are frequently called, standing stones, as found in both regions. The connection between the inhabitants of these regions was further shown by the physical conformation of the races, by the similarity of many of their manners, customs, and observances, and by the decided and extensive affinity of the Celtic, and other languages of western Europe, with the Sanscrit.

Taking advantage of the special attention paid at present to certain astronomical disquisitions, the author called attention to a particular point connected with the moon, which was first stated by the author of “The Plurality of Worlds,” and then made by him to prove that the moon must be uninhabited, and thence to lead to the conclusion that all the other planets were uninhabited also. This point was, that “observations having been made on the moon abundantly sufficient to detect the change caused by the growth of such cities as Manchester and Birmingham, no such changes having been perceived, the theory of non-habitation may be indulged in.”

Considerable attention has of late been bestowed on the equitable mode of computing the interest which ought to be charged for fractional portions of a year. Various opinions have been offered relative to the solution of the problem. The basis on which they mutually rest, and on which it appears to me that every solution of the problem must rest, is this—“That the interest chargeable for any fractional part of a year shall at the end of the year amount to a sum which bears the same proportion to the whole annual interest that the period bears to the whole year.”