The author describes an apparatus by means of which the explosive power of gaseous combinations can easily be determined, and from this, by Bunsen process, the temperature may readily be calculated. The essential feature of the apparatus is the registration of the ‘compression volume’ of a given initial volume of air, on which the gaseous explosive mixture has been allowed to act. As the duration of the pressure is all but instantaneous, the well-known formula

may be employed to ascertain the final pressure, more especially as the sudden rebound prevents any great loss of heat.

The ordinary Sprengel, requiring careful manipulation, and being apt to get out of order, has not yet become an essential piece of lecture apparatus as it ought to be. The author exhibited to the Society two modifications adapted to lecture illustration. In both instruments the mercury receptacle is made of iron, and instead of the india-rubber joint of the original, a well-ground iron stopcock is substituted, the portion of iron tube before the stopcock terminating in a Y-shaped piece bored out of the solid. In the one form the drop-tube is of glass, attached by means of marine glue; in the other, of carefully made india-rubber tube four or five millimetres in thickness, of a very small uniform bore, made expressly for the purpose by the Edinburgh Rubber Company.

In the former parts of this investigation we studied the physiological action of the salts of a considerable number of ammonium bases—that is, of the salts formed by the union of an ether with the nitride of one or more alcohol radicals. Thus—

The examination of the physiological action of such salts proved that, while differing from one another in many respects, there are two points in which they agree—they all paralyse the end-organs of the motor nerves, and none of them possess that stimulating action of the spinal cord which we observe in such a substance as strychnia.

So far as regards the annual amounts of the rainfall of Scotland, deduced from observations made at 296 different places, the chief point brought out is the enormous difference between the rainfall of the west and that of the east; the stations along the west coast showing such figures as 40, 45, and 54 inches, as compared with 24, 27, and 30 inches at stations on the east coast, not situated in the immediate neighbourhood of hills. When it is considered that the source of the rainfall is the prevailing south-westerly winds, it is evident that the comparative dryness of such districts as the south shore of the Firth of Forth is due to high land lying to the south-west, which drains the winds of a large portion of their moisture in their passage across them.

When the linear and vector function expressing a strain is self-conjugate the strain is pure. When it is not self-conjugate, it may be broken up into pure and rotational parts in various ways (analogous to the separation of a quaternion into the sum of a scalar and a vector part, or into the product of a tensor and a versor part), of which two are particularly noticeable. Denoting by a bar a self-conjugate function, we have thus either where є is a vector, and q a quaternion (which may obviously be regarded as a mere versor).

Professor Tait has considered the question of finding the square root of a strain, or what is the same thing, that of a matrix of the third order— A mode of doing this is indicated in my “Memoir on the Theory of Matrices” (Phil. Trans., 1858, pp. 17–37), and it is interesting to work out the solution.

The notation and method will be understood from the simple case of a matrix of the second order. I write to denote the two equations, x1 = ax + by, y1 = cx + dy.

1. Let ψ, φ … be the values at time t, of generalised co-ordinates fully specifying the positions of any number of solids movable through space occupied by a perfect liquid destitute of rotational motion, and not acted on by any force which could produce it. Some or all of these solids being perforated, let χ, χ′, χ″, &c., be the quantities of liquid which from any era of reckoning, up to the time t, have traversed the several apertures.

About a year ago, the Council of this Society appointed a Committee to make inquiry about boulders in Scotland.

The Committee intend to submit to the Council a general report of their proceedings, showing the progress made.

The object of the present notice is to give to the Society an account of one of the boulders reported to the Committee, as a specimen of the information which they have been obtaining.

The cultivation of the Ipecacuan plant in this country has received an impetus from the demand on the part of his Grace the Duke of Argyll, for a large supply of fresh plants for India. The object of the India office is to cultivate the plant extensively, and thus prevent the evils which might arise from scarcity of a drug which is so important in the treatment of dysentery. The risk of such an occurrence is due to the mode in which the plant is gathered in Brazil, and the want of care in preserving it. A similar fate threatens Ipecacuan as that which has occurred in the case of Cinchona.

The attention of the Society was called to many beautiful specimens of Sphenopteris laid on the table. These had been obtained by Dr Duns and his predecessor, Dr Fleming, from the old workings in the Burdiehouse limestones, near Edinburgh, well known from Hibbert's Memoir (1835), and from the papers of more recent observers. The species exhibited were chiefly S. artemisiæfolia and S. affinis. An Antholite (A. Pitcairniœ) was also shown, in which the pedicels that spring from the flower-like buds in the axils of the bracts, sub-opposite in the spike, are well represented. The author then referred to Cardiocarpon, Brong., and to the species named by Brongniart, Lindley, and Hutton, and more recently by Dawson and Lesquereux. It was pointed out, that very many Cardiocarpa occur in association with the specimens of Sphenopteris on the table.

Having had occasion lately to fill up some blanks in a table of the Nutritive Value of different kinds of Food, I was unable to find for the purpose an analysis of the flesh of the Salmon. I have therefore made such an analysis as is necessary; and as the results may be useful to others, I beg to offer them to the Society.

I first examined the composition of a very fine “Clean” fish, caught in the estuary of the Tay in May last year, and weighing 20 pounds. I have never seen a finer fish from that far-famed salmon-river.

After referring to the recent discussion on the temperature of the sun, in which Secchi, Zollner, Vicare, Deville, and Ericsson have taken part, the author proceeds to group all the known methods of arriving at a knowledge of high temperatures under eight different processes.

The author begins this paper by calculating the highest hypothetical temperature that could be produced by the chemical combination of the most energetic elements if all the heat evolved could be thrown into the product. This would not exceed 19,500° C. in the case of silica, and 15,000° C. in the oxides of aluminum and magnesium, and these are the highest results. The estimation of the temperature of the electric spark is based on the thermal value of each spark, together with the volume of the same. The methods of observing these quantities are fully detailed in the memoir. The general result may be stated thus,—the temperature of the electric spark used in the experiments ranged between 10,000° C. and 15,000° C.

After summarising the conclusions at which he had arrived from numerous experiments made more than forty years ago, as published in his Treatise on Poisons, and in the Transactions of this Society, the author alluded to various blanks left at that time in the inquiry which had not been yet filled up, and to various criticisms and doubts which had been recently expressed relative to the facts and principles formerly announced.

My attention was called in January last year to the rusting of iron vessels by observing that the bilge water of my yacht (the “Myanza”, 214 tons) was much discoloured by red oxide. Knowing that bilge water is apt to become acid, and thus to attack iron, the result was easily accounted for. Even when the water does not become acid, we may expect some action on the iron to take place when sulphuretted hydrogen exists, as it frequently does there, in which case, first a sulphide, then an oxide, and some sulphate, are formed. The remedy seemed to be easy, because the acid can be neutralised by lime. This earth would also prevent the formation of sulphuretted hydrogen.

In April 1871, a paper was read in this Society proposing a scheme for the conservation of boulder or erratic blocks in Scotland, in so far as they were remarkable for size or other features of interest. The Council of the Society approved of the scheme, appointed a committee to carry it out, and agreed to aid in meeting the expense of any circulars which might be necessary for conducting the inquiries.

The objects of the committee were twofold. They were first to ascertain the districts in Scotland where any remarkable boulders were situated; and, second, to select those which might be deemed worthy of preservation, with the view of requesting landed proprietors and tenants of farms not to destroy them.

The labours of the committee have as yet been directed only to the first of these objects.

Of all the processes proposed to measure varying luminous intensities by means of chemical effects, not one has yet been expressed in strictly dynamical measure. This is owing to the very small amount of energy to be measured necessitating very peculiar processes for its recognition. The chemical actions generally induced by light are of the “Trigger” or “Relay” description; that is, bear no necessary relation to the power evolved by the transformation. There is one natural action of light continuously at work of a very different kind in the decomposition of carbonic acid by plants, necessitating a large absorption of energy, and thus enabling us to ascertain the proportion of the radiant power retained, through the chemical syntheses effected.