XIII. "Researches into the nature of the Involuntary Muscular Fibre." By GEORGE VINER ELLIS, Esq., Professor of Anatomy in University College, London. Communicated by Dr. SHARPEY, Sec. R.S. Received June 11, 1856.

(Abstract.)

Having been unable to confirm the statements of Professor Kölliker respecting the cell-structure of the involuntary muscular fibre, the author was induced to undertake a series of researches into the nature of that tissue, by which he has been led to entertain views as to its structure in vertebrate animals, but more especially in man, which are at variance with those now generally received. The present communication contains the results of these inquiries, which tend to show that the voluntary and involuntary muscles resemble each other very closely in the arrangement and constitution of their fibres.

After adverting to the present state of opinion on the subject, the author gives an account of his own observations, and treats successively of the interweaving of the fibres, their size, form, and ultimate structure; their mode of attachment at their extremities, their length, and the corpuscles connected with them. He devotes a section also to the question of the periodic formation and destruction of muscular fibres in the uterus, in its different conditions; and while he is led by his own investigations to recognize an enlargement in size of the individual fibres of that organ during pregnancy, followed by subsequent diminution, he is unable to confirm the doctrine of new formation. Moreover, he finds that during pregnancy a considerable amount of granular matter, with round or oval granular-cells, is deposited among the fibres. He adduces reasons for believing that this substance cannot be regarded as a blastema, nor its imbedded cells as formative cells, for the production of new fibres; and he is disposed to ascribe the enlargement of the uterus in pregnancy principally to the enlargement of the muscular fibres, and the addition of this new deposit.

The following is a summary of the conclusions which the author has arrived at on the main subject of his inquiry :

In both kinds of muscles, voluntary and involuntary, there is an interweaving of the fibres with the formation of meshes.

The fibres in both kinds are long, slender, rounded cords of uniform width, except at the ends, where they are fixed by tendinous tissue; and in both, the size of the fibres in the same bundle varies greatly.

In neither voluntary nor involuntary muscle is the fibre of the nature of a cell, but in both is composed of minute threads or fibrils.. Its surface-appearance in both kinds of muscle allows of the supposition that in both it is constructed in a similar way, namely, of small particles or sarcous elements," and that a difference in the arrangement of these elements gives a dotted appearance to the involuntary and a transverse striation to the voluntary fibres.

The length of the fibres varies in both cases with the organ or part examined, and the connexion with tendon always takes place after the same manner, whether the fibre is dotted or striated.

On the addition of acetic acid, fusiform or rod-shaped corpuscles make their appearance in all muscular tissue; these bodies, which appear to belong to the sheath of the fibre, approach nearest in their characters to the corpuscles belonging to the yellow or elastic fibres which pervade various other tissues; and, from the apparent identity in nature of these corpuscles in the different textures in which they are found, and especially in voluntary as compared with involuntary muscle, it is scarcely conceivable that in the latter case exclusively they should be the nuclei of oblong cells constituting the proper muscular tissue.

The paper concludes with a statement of the mode of procedure which the author has found most suitable for examining the tissue which forms the subject of his inquiry.

XIV. "Account of the Construction of a Standard Barometer, and of the Apparatus and Processes employed in the Verification of Barometers at the Kew Observatory." By JOHN WELSH. Communicated by J. P. GASSIOT, Esq., F.R.S., Chairman of the Kew Observatory Committee of the British Association.

(Abstract.)

After stating the results of experiments, made under the superintendence of the Kew Committee, for the construction of a barometer tube of large diameter by the usual method of boiling the mercury in the tube, the author proceeds to describe a method of filling a tube with the aid of an air-pump. In this process, which is fully detailed in the paper, the tube is so constructed, that when the air has been extracted from it, the mercury enters by atmospheric pressure, provision being made for entirely removing the air which the air-pump has failed to extract. By this method a barometer tube of 1.1 inch internal diameter has been satisfactorily prepared at the Kew Observatory. The author then describes the mounting and mode of observing the standard barometer, proceeds to explain the processes adopted in the verification of barometers, and gives a detailed description of the apparatus for determining the errors of barometers at different atmospheric pressures.

XV. "On the Aurora." By REUBEN PHILLIPS, Esq. Communicated by Professor STOKES, Sec. R.S. Received March 7, 1856.

In this paper the author enters into various speculations as to the formation and motion of auroral arches. Since it has been found by experiment that the maximum length of the voltaic arc with a given battery is nearly the same in atmospheric air and in highly rarefied air, forming a very perfect vacuum, the author conceives that a streamer begins as a disruptive discharge of finite and very moderate length, (the maximum length very nearly of a continuous discharge,) which starts upwards from the auroral arch, which he

regards as the discharging train. If this first portion be not parallel to the dipping-needle, it is moved laterally by virtue of the earth's magnetism, and thus wrenched, as it were, from the spot where it was formed, and extinguished. If, however, the discharge, or any portion of it, be parallel to the dipping-needle, it is not influenced by the earth's magnetism, and remains. To this first length another length may be added by a similar process, and so on, these successive lengths being all parallel to the direction of the first, since otherwise the streamer would be torn asunder by the lateral motion resulting from the earth's magnetism. Thus a straight streamer extends upwards in a direction parallel to the dipping-needle.

If, from some increase in the power of conduction of the arch, the base of the streamer be not necessarily confined to a single spot, then a streamer may be formed which is somewhat inclined to the dippingneedle; but the consecutive elements of such a streamer must be in the same direction, otherwise they would have different lateral motions, the streamer would be divided, and the discharge would cease. The streamer, as a whole, will move from east to west, or from west to east, according to circumstances. Those streamers which would tend to move north or south cannot exist, because their bases would be severed from the auroral arch.

If the discharge take place in air not so very highly rarefied, so that the disruptive discharge is not quite of its maximum length, consecutive elements need not be quite in the same direction in order that the streamer may be unbroken, and thus curved streamers may be formed. It is stated by M. Biot that such have sometimes been observed.

The author then enters into some speculations as to the nature of the auroral arch, which he conceives to consist of nebulous matter highly charged with electricity, and accounts, according to his views, for the motion of such arches from the pole towards the equator.

The remainder of the paper is occupied with speculations as to the nature of fire-ball lightning, and other subjects relating to ordinary electricity.

XVI. "On the Lunar-diurnal Magnetic Variation at Toronto." By Major-General EDWARD SABINE, R.A., D.C.L., Treas. & V.P.R.S. Received June 13, 1856.

(Abstract.)

This paper contains the results of an investigation into the moon's diurnal influence on the horizontal and vertical components of the magnetic force at Toronto, and the consequent deduction of the lunardiurnal variations of the inclination and of the total force at that station. The observations from which the results were obtained consisted of five years of hourly observation of the bifilar and vertical force magnetometer, ending June 30, 1848, from which the disturbances of largest amount had been separated as described in a paper previously communicated (Phil. Trans. 1856, Art. XV.). The results derived from the mean of the five years are confirmed by the accord which is shown of the means of each of the half-periods into which the observations of the five years are divided for that purpose.

To complete the view of the moon's diurnal influence on the magnetic elements at Toronto, a recalculation has been made of the lunar-diurnal variation of the declination from the mean of six years of hourly observation, ending June 30, 1848, employing the more perfect normals derived from the exclusion of the larger disturbances, as described in the paper above referred to (Phil. Trans. Art. XV. 1856); and the confirmation is shown of the mean result of the six years by the accordance of three separate portions of two years each, into which the whole period of six years has been divided for that purpose.

From these premises the author draws the following conclusions:

1. The three magnetic elements concur in showing that the moon exercises a sensible magnetic influence at the surface of the earth, producing in every lunar day a variation which is distinctly appreciable, in each of the three elements, by the instruments adopted and recommended in the Report of the Committee of Physics of the Royal Society, when due care is taken in conducting the observations, and suitable methods are employed in elaborating the results.