Depuis Murray et Eenard deux travaux importants sont venus enrichir la bibliographie de la Glauconie: le mémoire de MM. Calderon et Cliaves, “Contribuciones al estudio de la Glauconita,” et l'œuvre magistrale de M. L. Cayeux, Etude micrographique des terrains sédimentaires.

Murray et Eenard avaient étudié spécialement la Glauconie actuelle; MM. Calderon et Cliaves baserent leur synthese de la Glauconie actuelle sur une analyse de Glauconie des roches sédimentaires; M. L. Cayeux limita strictement ses belles recherches à la Glauconie des roches sédimentaires et n'attaquapas le problème de sa genèse.

1. The diet of five halls of residence was studied. This represents the food of 1129·4 men for one day.

2. The average amount taken per man per day was: proteids, 143 grammes; fats, 138 grammes; carbohydrates, 511 grammes; with a fuel value of 3979 Calories.

3. In all the studies the proteid value is high. The animal proteid is 63 per cent, of the total proteid.

4. The average cost per man per day (exclusive of beverages and condiments) is 15·1 pence. Sixty-six per cent, of this is expended on animal food.

5. The amount of nutritive material per penny is much lower than that given in the study of the diet of Edinburgh labourers' families.

6. The waste varies considerably. The approximate cost of waste was from 2·4 per cent, to 7 per cent, of the total money spent on food.

7. The proteids and carbohydrates are higher than in the American college studies. As the fats are lower, the Calorific value is about the same. The amount of food taken is greatly in excess of that in Japanese students' dietaries.

8. The waste is only about one-half of that in the American studies of college residences.

9. The expenditure on food of 9s. 2d. per man per week seen in this study is probably about the average spent on a middle-class dietary.

When sulphur to which after recrystallisation no air has had access is melted, or when ammonia is led for a few minutes through ordinary sulphur after it has been melted, the two forms of liquid sulphur (yellow, mobile Sλ, and brown, viscous Sμ) adjust themselves very rapidly to those proportions which are in equilibrium at that temperature to which the liquid may have been raised. The adjustment occupies but a few moments. When specimens thus prepared are then chilled by plunging into water, the reversion of the Sμ to Sλ is equally rapid, and therefore the product is wholly brittle, crystalline, monoclinic sulphur. This behaviour is observed whether the liquid has been heated at, say, 155°, where the amount of Sμ, at equilibrium is 7·2 per cent., or at 448°, where the amount is at least 34 per cent.

My last communication in reference to the history of alternants dealt with the period 1795–1841 (Proc. Boy. Soc. Edin., xxiii. pp. 93–132). The present paper continues the history up to the year 1860, but in addition contains an account of three writings belonging to the previous period, namely, by Murphy (1832), Binet (1837), and Haedenkamp (1841).

So far as mathematical writers have as yet noted, a set of equations of the type

had not made its appearance in mathematical work prior to the year 1846: and it is almost absolutely certain that before that year the determinant of such a set had never been considered. It is not at all unlikely, however, that the expression

which is the case of the determinant for n equal to 3 had more than once turned up in other connections, and that its divisibility by a + b + c had been noted: but of this, too, there is no record.

The form described in the present paper was found amongst the contents of the stomach of a Weddell seal (Leptonychotes weddelli), taken by the Scottish National Antarctic Expedition in Scotia Bay, South Orkneys. In all about sixty specimens were collected. They occurred unattached amongst material in a semi-fluid condition, so that it is not possible to state definitely whether the seal or some animal upon which it fed is the normal host of this parasite. This question, however, in the case of the Echinorhynchi, appears from the work of de Marval to be one of minor importance. He has shown that in the Echinorhynchi of birds there is a most marked absence of specialisation of hosts, and quotes from other authors various instances of the same parasite occurring in different vertebrate classes. The worms in the present case showed no indication of having been affected by the digestive juices of the seal. As will appear from the description given below, their structural peculiarities suggest relationships with certain forms known to inhabit aquatic birds.

In a paper on the aluminium anode by one of us, in conjunction with Inglis, it was pointed out that if the suggested theory of the aluminium anode is correct, a precipitation film of aluminium hydroxide should dimmish the conductivity of salt solutions to very different extents depending upon the ions present, and that, e.g., the diminution in the case of potassium chloride might be expected to be slight, in the case of potassium bromide somewhat greater, and in the case of potassium sulphate to be very considerable. Preliminary experiments to measure these differences directly were not successful, almost certainly, as was stated at the time, because of the difficulty of freeing the precipitation membrane from the concomitant soluble impurities.

Aus Leptenychotes weddelli Lesson. Ventric. Das Kopfende ist erheblich diinner als das Schwanzende. Die Lippen sind klein, die Dorsallippe ist 0·18 mm. breit und 0·14 mm. lang; aussen an der Vorderseite gerundet, Papillen nach aussen und vorn gerückt, innen mit einem doppelten, rechtwinklig begrenzten Vorsprung, ohne Zahnleisten, Löffelbildung und Zwischenlippen (fig. 1). Cuticula quergeringelt, Nacken - papillen fehlen; Schwanzende abgerundet, beim Weibchen sehr breit. Der Ösophagus ist kurz und schmal und nimmt der Gesammtlange länge ein; in seiner vorderen Hälfte ist er muskulös, in der hinteren drüsig, das Lumen ist aber überall drei-schenklig; immuskulösen Theil verlaufen 3 Drüsen (fig. 3, a); an der Dorsalseite der Ösophagus verläuft eine breite, blinddarmartige Vörlangerung des Darms nach vorn, die weit nach vorn reicht (fig. 3, b); nieht so lang wie der ösophagus sondern von der Ösophagus-Länge; die das Lumen auskleidende Membran sowie die äussere Hülle sind dick.

Our knowledge of Antarctic Aptera has been growing rapidly during the last few years, a number of species from remote southern regions having been described by Willem (1902) from the countries south of Patagonia explored by the Belgica, by Schaffer (1897) from Tierra del Fuego, by Enderlein (1903) from Kerguelen, and a single Isotoma by the present writer (1902) from South Victoria Land. We find in the Antarctic as in the Arctic regions that in our advance towards the most remote and inhospitable lands, where winged insects eease to be represented, the primitive Aptera are still found fairly numerous in species, and often multitudinous in individuals. A careful study of these small frail insects fully repays the naturalist, both on account of the interest of their structure and the light which their distribution throws on geographical problems.

The rise and decline of epidemics of infectious diseases have been subjects of interest since the earliest times, but the scientific determination of the laws which govern their course offers even yet a wide and almost unworked field. Not but what a large amount of observation has been made on many of the conditions under which epidemics appear and pass away. Many epidemics are seasonal, and these have been studied; but the lack of any means of determining the course which a given epidemic might have taken in the presence of somewhat different conditions has made the deduction of certain conclusions impossible. Even the laws which regulate solitary outbursts of disease, the special subject of this paper, have been little studied. Explanations offered have varied with the period in history.

The half-shade effect in polarimeters is usually obtained, either by the well-known, method of Laurent, or else by the more recent method of Lippich. In the former a quartz plate is employed to give the necessary rotation to one-half of the beam of polarised light propagated through the instrument; in the latter, a Nicol prism additional to the polariser serves the same end.

It occurred to the author that the required effect might be obtained very simply by merely interposing a glass plate in the beam of light, so that half the beam traversed it, in an oblique direction. It follows at once, from Fresnel's laws of the intensity of refracted light, that this will produce a slight rotation of the vibration-direction in the traversing half of the beam.

In practice the method is found to give very good results.

There is a well-known law in geometrical optics, that the “intrinsic luminosity” of the image formed by any lens system whatever is the same as the intrinsic luminosity of the object. An exception, however, which seems not to have been pointed out before, exists in the case of polarised light, based on the fact that by the agency of a double-image prism two light rays polarised in directions mutually perpendicular may be combined into one ray, which carries the total energy of both. In this way an intrinsic luminosity of image can be attained which is twice as great as that of the object.

(1) The cubinvariant J of a binary quartic being

its Hessian, H(J), is

Performing on this the operations

and on the result the operations

we obtain

The three-line determinant here is seen to contain c as a factor, because it manifestly vanishes when c is put equal to 0.

(1) If we temporarily denote the product of the rth and sth rows of a determinant Δ by rs, we shall have conveniently