The chief pigment of normal urine is known as urobilin (seeing that this name indicates a relation to “bile,” “urochrome” would be a better term, not connoting any view as to genetic relationship). The name for the chromogen “urobilinogen” would become “urochromogen.” Other pigments are or may be present in normal urine, e.g., the indigo-blue pigment whose ancestor is intestinal indol, and “uroerythim” genetically related, it is believed, to skatol, while, according to some physiologists, traces of “pathological urobilin” (which, might be better called para-urochrome) and even of hæmatoporphyrin are recognisable in healthy urine.

Certainly, in some morbid urines, urohæmatoporphyrin has been the chief pigment replacing urobilin, while, in a few very rare ones, a pigment allied to it, but, according to M'Munn, less de-oxidised, has appeared. This substance, like urobilin and urohæmatoporphyrin, is a proteid-free, iron-free pigment, as yet unnamed. I propose to call it meio-de-oxyhæmatoporphyrin. Urobilin is amber-coloured, urohæmatoporphyrin makes the urine of orange tint, while the rarer ally gives it a deep port-wine colour: urines containing this last do not decompose for many weeks.

I lately encountered meio-de-oxyhæmatoporphyrin in the urine from a case of rare skin-disease, Dermatitis herpetiformis bullosa. Both these hæmatoporphyrins have absorption-spectra resembling that of alkaline hæmatoporphyrin, and each, on the addition of strong sulphuric acid, is changed to the characteristic two-banded acid-hæmatoporphyrin.

In this paper the author confines his attention to the relations of the organ, and especially to the structure of Jacobson's cartilage, the nasal floor cartilage, and the different developments to which they give rise. From the study of a large series of forms he has been led to the following general conclusions:—(1) That the organ is generally well developed in the primitive groups, and feebly developed in the higher forms; (2) that among allied animals the organ is, as a rule, better developed in the small species than in the large; (3) that in the various members of each Natural Order the organ is constructed on a common type, which admits of only very slight variation; and (4) that, even when the organ is quite absent in certain members of an Order, the nasal floor cartilages are constructed on the same type as in those members in which the organ is developed.

From the very slight tendency there is in the organ and its cartilaginous adjuncts to vary with changing habits, the author concludes that the anatomy of the region affords a valuable factor in classification. A study has been made in most of the Mammalian orders, and the relationships and inter-affinities of the different types have been critically examined.

In the Monotremata the organ is very well developed. The simple nasal floor cartilage in front gives rise behind to Jacobson's cartilage and a well-developed outer nasal floor cartilage, which latter passes inwards and supports Jacobson's cartilage. In this order Jacobson's cartilage differs from all other mammals, and resembles lizards in forming a well-marked turbinal process.

§ 1. To test whether or not the Röntgen rays have any electrifying effect on air, the following arrangement was made.

A lead cylinder 76 cms. long, 23 cms. diameter, was constructed; and both ends were closed with paraffined cardboard, transparent to the Röntgen rays. Outside the end distant from the electrometer (see diagram 1) a Röntgen lamp was placed. In the other end two holes were made, one in the middle, through which passed a glass tube (referred to below as suction pipe) of sufficient length to allow the end in the lead cylinder to be put into any desired place in the cylinder. By means of this, air was drawn through an electric filter by an air pump. The other hole, at a little distance from the centre, contained a second glass tube by which air was drawn through india-rubber tubing from the open-air quadrangle outside the laboratory.

In one series of experiments the end of the suction pipe was kept in the axial line of the lead cylinder at various points 10 cms. apart, beginning with a point close to the end distant from the Röntgen lamp.

In every case the air drawn through the filter was found to be negatively electrified when no screen or an aluminium screen was interposed between the Röntgen lamp and the near end of the lead cylinder. The air was found not electrified at all, or very slightly negative, when a lead screen was interposed.

§ 1. Apparatus for realising the proposed method is represented in the accompanying diagram. Two Woulffe's bottles, each having a vertical glass tube fitted air-tight into one of its necks, contain the liquids the difference of whose vapour pressures is to be measured. Second necks of the two bottles are connected by a bent metal (or glass) pipe, with a vertical branch provided with three (metal or glass) stopcocks, as indicated in the diagram. Each bottle has a third neck, projecting downwards through its bottom, stopped by a glass stopcock which can be opened for the purpose of introducing or withdrawing liquid. The upper ends of the glass tubes are also connected (by short india-rubber junctions or otherwise) with a bent metal pipe carrying a vertical branch for connection with a Toepler mercury air-pump. This vertical branch is provided with a metal stopcock. The vertical branch of the pipe fitted into necks of the two bottles is also connected to the air-pump as indicated in the drawings.

§ 2. To introduce the liquids, bring open vessels containing them into such positions below the bottles that the necks project downwards into them. Close the glass stopcocks of these lower necks, open all the other six stopcocks, and produce a slight exhaustion by a few strokes of the air-pump. Then, opening the glass stopcocks very slightly, allow the desired quantities of the liquids to enter, and close them again.

In a paper on mixtures of ethane and nitrous oxide, read before the Physical Society of London in May 1895, I communicated a set of observations with regard to the condensation and the critical state of ethane. This substance was prepared by electrolysing sodium acetate: it was purified with fuming sulphuric acid, caustic soda, and phosphorus pentoxide, and condensed in a small copper cylinder, where it was subsequently boiled at low temperature in order to expel all permanent gas. The ethane with which the glass compression-tubes were filled was drawn from the liquid contained in the copper cylinder. Its condensation-pressures and critical constants are contained in the following table, which is taken from the paper mentioned (comp. fig. 3):—

The values of p and of the critical constants in Table I. are not absolutely correct. The observations showed the substance to contain some impurity, the condensation-pressures not being quite constant, but showing a slight increase, as is always the case for mixtures. The difference of the pressure at the beginning and at the end of the condensation amounted to 0·43 atmospheres at 15° C. It is, however, unlikely that this impurity in the ethane can have affected the values for p by more than a few tenths of an atmosphere. Nor will the value for the critical temperature differ by more than 0·1 or 0·27° C. from the true value, considering that Andrews' carbonic acid showed changes in vapour-pressure of over two atmospheres under the same circumstances, and that his value for the critical temperature, 30·9° C., is only about 0·4° C. too low.

Our power of estimating the direction of sound is much less accurate than that of estimating the direction of light; and, further, our knowledge as to the way in which this perception of direction occurs is much more limited in the case of sound. We judge with the greatest accuracy the direction of a ray of light, and we know that we do so almost entirely by the aid of the muscular sense. How do we judge the direction of a sound?

Before attempting a reply to this question it will clear that matter up, to a certain extent, by giving a statement of a few facts which have been found out by experiment, and are well attested by various writers:—

(1) Individuals who are deaf of one ear have little power of estimating the direction of sound.

(2) Individuals who are blind of both eyes generally show a power of judging the direction of sound far superior to those gifted with sight. This is particularly true if the eye affection dates from childhood.

(3) The power of estimating the direction of sound depends upon its pitch and its quality. A pure tone of low pitch is very difficult to localise; with the higher notes this becomes easier, and with a compound sound it is also easy.

(4) The accuracy with which we estimate the direction of a sound is greatest when the sound is in the line of axis of the two ears, and least when it is in the median plane of the body.

1. Let the <PAB be θ, where P is a point on the arc of a semicircle described on AB of which O is the middle point. Then making

<OPC = <OPA, the <PCB = 3θ.

Since the triangles APC, OPC are similar, we have

We shall express each of the ratios sin 3θ/sin θ, cos 3θ/cos θ, etc., as a function of AC/OC.

In a paper communicated to this Society I stated that, when, introduced into the stomach of an animal, serpents' venom produces no obvious injury, even when the quantity is so large as to be sufficient to kill 1000 animals of the same species and weight if the venom were injected under the skin. The failure of so highly toxic a substance to produce poisoning when it is administered by the stomach might be due to chemical changes produced upon it by the secretions of the stomach and intestines, or to non-absorbability into the blood from the stomach and intestines. It is already known that the toxicity of venom is not materially reduced by gastric digestion. Although at first sight incompatible with the innocuousness of stomach administration, this fact is not in reality a contradiction of it, for the absorbing power of the stomach for many organic substances—even for strychnine—has been shown to be extremely slight, and their entrance into the circulation appears to occur not in the stomach but in the intestines.

As serpents' venom introduced into the stomach is not rendered innocuous by the stomach secretions, while, notwithstanding, it fails to cause poisoning, it may be assumed that the stomach walls are incapable of absorbing it. If, like other poisons, it can be absorbed from the intestines, the explanation of the failure to produce toxic symptoms when it is administered by the stomach might depend on a chemical or physiological destruction of its toxic properties by some substance or substances which it encounters soon after entering the intestinal canal, and most probably, therefore, by the bile or the pancreatic secretion.

§ 1. It is proposed in the following paper to describe experiments made to test the electric state of the air in the neighbourhood of metallic uranium, or of other metals on which a salt of uranium had been deposited from a solution, when these were charged to a positive or a negative potential.

§ 2. Method employed. To test the electric state of the air the electric filter method* due to Kelvin, Maclean, and Gait was employed. The special filter used in the experiments to be described was a block-tin pipe, 10 cms. long and 1 cm. diameter, filled with brass filings. This was insulated on two tunnelled pieces of paraffin, and put in metallic connection with the insulated pair of quadrants of a quadrant electrometer. From one of the tunnelled pieces of paraffin a metal tube led to an air pump; from the other a piece of india-rubber tubing led to the place where the air to be tested was. This air was then drawn through the electric filter, and the deviation from the metallic zero of the electrometer, when the two pairs of quadrants were insulated, was noted. To give some idea of the efficiency of the filter, the results obtained when air was pumped away from the neighbourhood of the electrodes of a Ruhmkorff inductorium (Apps. pattern, 10-inch spark) will be given.

The phenomenon of Supersaturation in certain well-marked instances is familiar to every student, and may briefly be defined as consisting in the retention in solution at a low temperature of a quantity of a substance sufficient to form a saturated solution at a higher temperature. So long as the temperature is not allowed to fall below a certain point, and the solution is not brought in contact with a particle of the solid substance or with a substance isomorphous with it, the solution is in perfectly stable equilibrium. The researches of Gernez and many others have established this now generally accepted fact, that, the temperature remaining constant, the sole cause which is able to disturb the equilibrium of the solution is contact with a crystal of the same form as that which will crystallise out from the solution.

In a paper communicated to this Society nearly twelve years ago, I described a series of experiments on supersaturation which had forced me to the conclusion that in the strict sense of the word no solution is ever supersaturated, a conclusion which I found had been reached by Loewel nearly fifty years before, as the result of his investigations on the solubility of sodium sulphate. Shortly stated, the views of Loewel and myself were that a supersaturated solution is a saturated or non-saturated solution of the anhydrous salt, the term anhydrous being used by me as a convenient means of indicating that no definite hydrate exists in the solution, but that the whole of the water is in the same relation to the salt.

On the 12th of June a disastrous earthquake occurred in North-Eastern India. The violence of the shock was first felt in Calcutta (at least, the first report of it reached us from that quarter), and spread with destructive violence, north-easterly through Assam along the valley of the Brahmapootra, and north-westerly along the course of the Ganges and the base of the Himalaya Mountains. We may form some idea of the violence of the shock from the disastrous effects produced by it. From Calcutta it is reported that few houses have escaped without damage of some description, that part of the Cathedral spire has fallen, and that many public buildings have been injured. At Darjeeling many houses were destroyed, and the district left without railway communication. In Bengal the destruction of property was apparently not so great; but in Assam the shock is reported to have spread ruin far and wide, and to have been attended with serious loss of human life.

The destructive energy of the earthquake appears to have been exhausted within the area thus briefly indicated. The undulatory movements set up by it in the earth's crust have, however, been detected at great distances from the centre of the disturbance, and already from three stations in Western Europe reports are to hand showing that seismographic apparatus have recorded the phenomenon beyond any possibility of doubt. These stations are Grenoble in South-Eastern France, Prof. Milne's Seismological Observatory in the Isle of Wight, and the Royal Observatory on Blackford Hill. Doubtless in time we shall hear of similar records obtained at many other places.

In the Total Eclipse of 8th August last year, the line of totality began at a point to the north of the Shetlands, passed across the north of Norway, from Bodo on the west to Vadso in the north-east, then traversed Novaya Zemlya, Siberia, and Yesso, the northern island of Japan, ending finally in the North Pacific Ocean. Both Bodö and Vadsö are easily accessible by the Nor-wegian mail-boats, the former being, however, some four days nearer than Vadsö. At the first glance one would naturally inquire:—Why was not Bodö chosen for our station in preference to the more distant Vadsö ? The chief reason was the very important one that at Vadsö the sun, at the time of total eclipse, attained an altitude of 15° above the horizon, while at Bodö the altitude was only some 7°; at Vadsö, too, the duration of totality was 106 seconds, as compared with 101 seconds at Bodö. As regards the chances of a clear sky, there was not much to choose between the two stations; on the west coast the rainfall was reported to be relatively large, while fogs were said to be of frequent occurrence at Vadsö. Vardö, some 40 miles east of Vadsö, was declared unsuitable on account of a still greater likelihood of trouble from sea fogs in the early morning, during summer. We therefore fixed on Vadsö as our observing station, and communicated with Professor Mohn of Christiania, the well-known meteorologist, as to the best steps to be taken for securing a favourable site for our instruments. We are indebted to him for much valuable advice, and to Dr Caspersen of Vadsö for his very material help in securing comfortable rooms for us there.

In a paper read to the Society on March 1 (ante, p. 310) I spoke of the application of some of its results to the solution of equations involving an unknown Linear and Vector Function. These results depended chiefly upon the expression of the function in terms of its roots, scalar and directional; and I now give a few instances of their utility, keeping in view rather variety of treatment than complexity of subject. The matter admits of practically infinite development, even when we keep to very simple forms of equation, and is thus specially qualified to show the richness in resources which is so characteristic of quaternions. But it will be seen also to be strongly suggestive of the extreme caution required even in the most elementary parts of this field of inquiry.

On 5th July we had the pleasure of listening to the paper on the “Calcutta Earthquake” of 12th June 1897, by Mr Heath, B.A.

It occurred to me that the Royal Society might be pleased to have a narrative account from one of its Fellows, by following up the subject. There is nothing scientific in this paper, and it is brevity itself; at the same time it may be interesting, as the facts are from personal experience of some earthquakes during my residence in India of nigh quarter of a century.

Mr Heath observed casually that a portion of the spire of the (Episcopal) Cathedral at Calcutta had fallen, and from the news papers I read that many of the public buildings, such as the High Court of Judicature, the Museum, and many others, were badly injured. If any one would like to see photographs of these buildings before injury took place, I thought it might be of interest to place my albums at the disposal of the President; so that, after the meeting is over, I could, if required, turn up the pages—

But, to my subject.

After the lapse of forty-one years, I read in a paper recently that the centre of the volcanic disturbance which has caused so much destruction in different parts of Bengal is definitely ascribed to a spot in the Bay of Bengal. I have always hoped that an experience which I had many years ago might some day be made clear: that pleasure, I think, I have at last attained.