The Society now enters into its 90th session since its foundation. During the session recently concluded the number of its Ordinary Fellows has increased from 331 to 343. Twenty-two members were admitted during last session. In the twelve months ending with the 30th ultimo, death has laid his hands sparingly upon our brethren. During the former year we lost by death ten Ordinary and three Honorary Fellows, several of whom occupied during their lives a very high position in science. Last year has deprived us of only four Ordinary Fellows, and one on our Honorary list; and although these were all men of great estimation in their several professions, our Honorary Fellow alone, among them all, was widely known as a successful scientific labourer.

The Author showed by a historical review of the fortunes of Greece, through the Middle Ages, and under the successive influences of Turkish conquest and Turkish oppression, how the Greek language had escaped corruption to the degree that would have caused the birth of a new language in the way that Italian and the other Roman languages grew out of Latin. He then analysed the modern language, as it existed in current popular literature before the time of Coraes, that is, from the time of Theodore Ptochoprodromus to nearly the end of the last century, and showed that the losses and curtailments which it had unquestionably suffered in the course of so many centuries, were not such as materially to impair the strength and beauty of the language, which in its present state was partly to be regarded as a living bridge betwixt the present and the past, and as an altogether unique phenomenon in the history of human speech.

Reference was made to a previous paper by the author (Proceedings, 1867–8, p. 309), in which an attempt was made to apply to this subject the Theory of Dissipation of Energy.

Some years ago, a bar of German silver was procured, at the expense of the British Association, for the purpose of ascertaining whether its thermal, like its electric, conductivity is little altered by change of temperature. With this, Forbes' experiments have been carried out carefully through very great ranges of temperatures.

This was a mere preliminary notice of what promises to be at once an interesting and an extended inquiry, to which I have been led by some recent results in thermo-electricity. At present, it may be stated that at, and above, a red heat the electric conductivity of iron seems to fall off much faster with increasing temperature than that of platinum.

By the kindness of Dr Russell, of Bartholomew's Hospital, I have been enabled to experiment upon a ribbon of pure iron prepared by the late Dr Matthiessen. I reserve details until I can obtain the history and mode of preparation of the specimen examined, but I may state now that, when formed into thermo-electric circuits with various alloys of Platinum and Iridium (Proceedings, 1871–2, p. 773) it gives results, as to the position of neutral points, not differing more from those given under the same circumstances by various iron wires of commerce, than the latter do among themselves. Thus it appears that, in the thermo-electric diagram, the line even for pure iron is sinuous; and that the specific heat of electricity in it changes sign somewhere about a low red heat.

These experiments were undertaken in order to determine how closely the hypothesis “that the electric resistance in a pure metal is directly as its absolute temperature” holds for various metals at two easily ascertained temperatures,—that of the air in the room, and the boiling point of water. The apparatus used was a Wheatstone's bridge; one coil of wire kept in a vessel of water at the temperature of the air in the room being put against another, which could be heated up to 100° C. The experiments showed that the rate of increase of resistance with temperature was different for hard and soft specimens of the same metal, being always less in the hard.

The Chairman said:—Before the papers in our to-night's programme of business are taken up there is a statement which, at the special request of the Council of this Society, I have to make from the chair. I have been requested to allude to the deaths of three much esteemed Fellows of this Society, which have occurred since our last ordinary meeting—Professor Macquorn Rankine of Glasgow University; the Very Rev. Dean Ramsay, Edinburgh; and Archibald Smith of Jordanhill. The Council think that it is only a fitting tribute to the memory of our deceased colleagues that I should express regret at the loss which we, in common with others, have sustained, and that I should also briefly allude to their connection with this Society and with science, leaving to a future occasion the duty of giving a fuller biographical account of each.

Many of the common illustrations of probabilities are taken from games in which each hand, or trick, must necessarily be won by one player, and lost by the other. It becomes an interesting question to inquire what modification is introduced if we contemplate the possibility of a hand, or trick, being drawn—i.e. not won or lost by either player. The only difficulty lies in taking account of the limiting conditions.

Surgeon-Major Black exhibited twenty-five large photographic views of the late eruption of Mount Vesuvius, which had been executed by his brother, John Melton Black, Esq.

The Council of the Royal Society have awarded the Makdougall Brisbane Prize to George James Allman, M.D., F.R.S., Emeritus Professor of Natural History in the University of Edinburgh, for his memoir “On the Homological Relations of the Cœlenterata,” published in the Transactions of the Society for 1870–71.

The Council have carefully considered the proposed alterations in the laws as to the election of Ordinary Fellows which were remitted to them by the Society for re-consideration on 3d June last, and have agreed to recommend to the Society that there should be no limitation in the number of Fellows annually elected, and that the following alterations should be adopted.

The position of this new species of Ganoid, under our commonly accepted classification, the author gave as follows:—

After referring to the Polyodon folium of Laépède (the P. reticulata of Shaw, the Planirostra spatula of Owen), the paddle-fish or spoon-bill sturgeon of the Ohio and Mississippi and their tributaries, as a well-known species of the genus in question, Dr Handyside went on to state that the new species now to be described was first observed on a Chinese fishmonger's stall at Woosung, 12 miles from Shanghai, and had since been found in the Yang-tsze-Kiang, and, as was alleged, in the northern Japanese sea. He then sketched the history of the Polyodontidoæ family, and narrated the researches of Lacépède, Von Martens, Blakiston, Kaup, and Duméril.

Two years ago the author submitted to the British Association a preliminary report on the subject, which has not been prosecuted, owing to the exhaustive investigations of Professor Thomsen of Copenhagen, on thermal values. In the paper referred to, the results are calculated on the assumption of hydriodic acid evolving 15,000 heat units for equivalent in aqueous solution. The above number is much too high, according to Thomsen's recent experiments, who gave 13,170 as the true number.

When examining with the one inch object-glass of a compound microscope some pieces of Strathpeffer Albert coal, I happened to place on the stage a crystal of dichroite, and was surprised to observe its surface covered with circular impressions. Their resemblance to some which I had previously noticed on iron pyrites associated with Albertite, led to a further inspection, which showed that they were due to globular bodies of various colours distributed throughout the crystal in layers parallel to the respective faces.

A peculiarity was observed about the vernal equinox in 1871 in the shape of the zodiacal light, which deserves to be recorded. The appearance resembled a thin cone (such as is usually seen), extending to a great height, and-rising out of a broad low cone situated at its base. This was not an effect of sunlight, for it was visible hours after sunset. It was not peculiar to any time or place, for it was seen constantly in all parts of the south of Europe, viz., in the Bay of Biscay, all along the Mediterranean, in Malta, and in Sicily. It seems not unlikely that there are periodic changes in the appearance of the zodiacal light. Hence it is well to mention any such peculiarity. I have also to confirm what has so often been stated by other observers, that the direction of the axis of the cone is not always in the direction of the ecliptic, but changes its direction from night to night.

If we assume the excess of temperature above that of the air, v, to be the same throughout a transverse section of the bar, the equation for the flux of heat is—

where cρ is the water equivalent of unit volume of the bar, k its thermal conductivity, a its side, and hv the quantity of heat lost by radiation and convection from unit surface of the bar per unit of time, when the excess of temperature is v.

The value of the coefficient of conductivity for ice is an important desideratum in several branches of physics; and it derives additional importance from an application, explained in the second part of this communication, to the determination of the thermal conductivity of different substances in absolute measure. The brilliant researches of Neumann, and some ingenious experiments by M. Lucien De La Rive, afford us at present the only two determinations that we possess of this important quantity. The value found by Neumann is 0·114, while De La Rive makes it 0·138. The discrepancy justifies the publication of experiments on a some-what large scale, which gives us a close approximation to the truth.