convection, and conduction, and it was further necessary to improve on the calculation one of us had published on this subject in the Electrician for 1879, by taking into account the fact that the emissivity, as well as the thermal and electric conducting power, of the wire differed at different points in consequence of the difference of temperature.

Until we had completed the experiments described in this paper, we could, of course, only employ in this calculation values that we had guessed at as being something near the truth for the emissivity of platinum wire for different diameters and at different temperatures. Hence, after the completion of the experiments, we took up the mathematical investigation again, substituting for the emissivity such a function of the diameter of the wire and the temperature of the point as we had experimentally found it to be. Section IV. of the paper contains the investigation by which we finally arrived at the calculated distribution of temperature along the wire, and we have to express our sincere thanks to Prof. Henrici (whom we consulted as to the best method of practically solving the rather complex differential equation arrived at) for the warm interest that he has taken in the mathematical treatment of the subject, and for the many suggestions which he has made, and which have enabled us to arrive at the mathematical solution given in the paper.

Each wire to be tested was stretched along the axis of a horizontal water-jacketed cylinder 32'5 cm. long, 7'62 cm. external and 58 cm. internal diameter, the inner surface of which was blackened and kept at a constant temperature by a stream of cold water flowing through the jacket. The rate at which heat was lost by any one of the wires was measured by the product of the current passing through it into the P.D. (potential difference) maintained between its ends, while the ratio of the P.D. to the current gave the resistance of the wire, and, therefore, its temperature. Experiments were in this way made with various currents flowing through each of the nine wires.

As the variation of resistance with temperature is known to vary with different specimens of platinum, experiments were separately made to determine the actual law of variation of resistance with temperature up to 300° C. for each piece of wire that had been employed in the emissivity experiments.

In this later determination various thermometers were used, and the subsequent comparison of these thermometers with a Kew standard thermometer involved a vast amount of labour, from the fact that it is, or at any rate was not possible three years ago, to purchase from the Kew Observatory a standard thermometer reading from, say, 200° to 300° C., with a short, wide chamber at the base in which the mercury expanded below 200° C. All that could be obtained was a long thermometer which had been carefully tested between o° and 100° C., and the

we

remainder of whose tube had been simply calibrated for uniformity of bore. The consequence was that when desired to compare one of our thermometers reading, say, from 200° to 300° C., with the Kew standard, their bulbs were very far apart when both were immersed in the oil-bath, and with the tops of the mercury columns just above the surface of the oil. A short description is given in the paper of the devices employed to overcome this difficulty, and which enabled an accurate comparison to be made between the thermometers. On examining the curves, accompanying the complete paper, which show the emissivity for each temperature for each of the nine wires, we see that

(1) For any given temperature the emissivity is the higher the finer the wire.

(2) For each wire the emissivity increases with the temperature, and the rate of increase is the greater the finer the wire. For the finest wire the rate of increase of emissivity with temperature is very striking.

(3) Hence the effect of surface on the total loss of heat (by radiation and convection) per second, per square centimetre, per 1°C. excess temperature, increases as the temperature rises.

On comparing the loss of heat from the wire of 12 mils diameter when at 300° C. with that from the wire of 6 mils diameter when at 15° C., both being in an inclosure at 10° C., we see that the former loses per square centimetre of surface per second not

as much heat; arising from the fact that the emissivity—that is, the number of calories (gramme C.°) lost per second, per square centimetre of surface, per 1° C. excess temperature-of the 12 mil wire at 300° C. is 60 times as great as that of the 6 mil wire at 15°, the emissivity of the latter wire varying very rapidly near 15° C.

From the curves which accompany the complete paper, each curve giving the variation of emissivity with temperature for a particular wire, the following table has been drawn up, giving the emissivities of the various wires at eight useful temperatures, and it will be observed that, in consequence of our investigation having been made on wires of which the thickest was thinner than the thinnest ever previously used in absolute determinations of emissivity, the emissivities we have experimentally obtained are far greater than any previously arrived at.

must be something like 267 mils, or 6.8 mm., in order that the neglect of the second term may not make an error in e of more than 5 per cent., and something like 1.39 inches, or 35 3 mm., if the error is not to exceed I per cent.

Generally, then, we may conclude that to assume that the emissivity is a constant for wires whose diameters vary from a small value up to 1 inch is to make a large error in the case of the greater number of the wires, and an error of hundreds per cent. in the case of some of them.

Using the formula (3) which we have arrived at for determining the emissivity of platinum wires of different diameters at 300° C., it follows that to maintain a platinum wire 0'75 mil in diameter at 300° C. would require a current density of 331,000 amperes per square inch; and, if the emissivity of a copper wire of the same diameter and at the same temperature may be taken as being the same, it follows that to maintain a copper wire 0'75 mil in diameter at 300° C. would require a current density of 790,000 amperes per square inch.

November 26.-"A New Mode of Respiration in the Myriapoda." By F. G. Sinclair (formerly F. G. Heathcote), M.A., Fellow of the Cambridge Philosophical Society.

The Scutigeridæ respire by means of a series of organs arranged in the middle dorsal line at the posterior edge of every dorsal scale except the last.

Each organ consists of a slit bounded by four curved ridges, two at the edges of the slit, and two external to the latter. The slit leads into an air sac. From the sac a number of tubes are given off; these tubes are arranged in two semicircular masses. The ends of the tubes project into the pericardium in such a manner that the ends are bathed in the blood and aërate it just before it is returned into the heart by means of the ostia. In the living animal the blood can be seen through the transparent chitin of the dorsal surface surrounding the ends of the tubes; and in the organ and surrounding tissues cut out of a Scutigera directly it is killed the blood corpuscles can be seen clustering round the tube ends. If the mass of tubes of a freshly killed specimen are teased out under the microscope in glycerine, they can be seen to be filled with air. The tubes each branch several times. Each tube is lined with chitin, which is a continuation of the chitin of the exo-skeleton. Each tube is also clothed with cells, which are a continuation of the hypodermis. The tubes end in a blunt point of very delicate chitin.

I therefore hold that the respiratory organ in Scutigera holds a position intermediate between the trachea of Myriapods and the lungs of Spiders. I hold with A. Leuckart (Zeitsch. für Wiss. Zool., vol. i. p. 246, 1849, "Ueber den Bau und Bedeutung der sog. Lungen bei den Arachniden") that the trachea have developed into the lungs of Spiders and Scorpions, and I think that the organs in question form a series of which the lowest term are the tracheæ, the next the organ of Scutigera, then the lungs of Spiders, and then of Scorpions.

Zoological Society, November 17.-Dr. A. Günther, F.R.S., Vice-President, in the chair.-The Secretary read a report on the additions that had been made to the Society's Menagerie during the month of October 1891, and called special attention to the following: a young Buffon's Skua (Stercorarius parasiticus), captured near Christchurch, Hampshire, and presented by Mr. E. Hart, and a Land-Crab (Geocarcinus ruricola) from the island of Fernando de Noronha, brought home and presented by Mr. D. Wilson-Barker.-The Secretary read a letter from Dr. G. Martorelli, of Milan, inclosing a coloured drawing of both sexes of a hybrid Duck bred in the public Garden of Milan, between Branta rutina & and Anas boschas 9.Mr. G. A. Boulenger gave an account of the various forms of the Tadpoles of the European Batrachians, and a statement of the characters by which the different species may be distinguished in this stage of their existence. - A communication was read from

Shells from New South Wales, New Guinea, and the Caroline and Solomon Islands, based on specimens lately presented to the British Museum by Mr. John Brazier, of Sydney.-Lord Walsingham gave an account of the Microlepidoptera of the West Indies, based primarily on the collections made in St. Vincent and other islands by Mr. H. H. Smith, under the direction of the joint Committee of the British Association and the Royal Society for the exploration of the Lesser Antilles.-A communication was read from M. E. Simon containing the first portion of an account of the Spiders of the island of St. Vincent, based on specimens obtained under the direction of the same Committee.-A communication was read from Mr. H. Nevill, urging the importance of founding an experimental Zoological Station in the tropics, and advocating the claims of Trincomalee in Ceylon for such an institution.-Dr. Johnson Symington read a paper on the nose, the organ of Jacobson, and the dumb-bell shaped bone in the Ornithorhychus.-Mr. A. Smith-Woodward read a paper on a Mammalian tooth from the Wealden formation of Hastings, being the first trace of a Cretaceous Mammal discovered in Europe. This remarkable fossil the author was inclined to refer provisionally to the genus Plagiaulax of the Purbeck Beds, and to call Plagiaulax dawsoni, after its discoverer.-A communication was received from Mr. C. Davies Sherborne, giving an exact account of the dates of issue of the parts, plates, and text of Schreber's "Säugethiere.' Great difficulties in synonymy had arisen from previously imperfect knowledge of these dates.

December 1.-Mr. Henry Seebohm in the chair.-Mr. Sclater exhibited a specimen of a Shearwater obtained near Sydney, and brought from Australia by Prof. Anderson Stuart. This specimen had been determined by Mr. Salvin to belong to Puffinus gavia, a New Zealand species not hitherto known to occur in Australia. -Mr. Seebohm exhibited and made remarks on specimens of several very interesting birds recently obtained in Ireland. Amongst these was an example of the Yellow-browed Warbler (Phylloscopus superciliosus) obtained on the Tearaght Rock, the most westerly station in Europe. Dr. E. Hamilton exhibited a specimen of the Redbreasted Snipe of North America (Macrorhamphus griseus), obtained in Scotland.-Mr. W. B. Tegetmeier exhibited some specimens illustrative of the abnormal form of the bill in birds caused by injuries to that organ during life.-Mr. G. A. Boulenger read some notes on specimens of Reptiles from Transcaspia recently received by the British Museum, and pointed out that examples of several well-known Indian species occurred in this collection.-A communication was read from Miss E. M. Sharpe containing the second portion of her descriptions of new Butterflies from British East Africa, collected by Mr. F. J. Jackson during his recent expedition. Mr. A. D. Michael read a paper upon the association which he had observed between certain Acarines of the family Gamasida and certain species of Ants. The author came to the following conclusions: (1) that there is an association between some Gamasids and Ants; (2) that a species of Gamasid usually associates with one or two species of Ant preferentially; (3) that the Gamasids of Ants'-nests are not usually found elsewhere; (4) that the Gamasid abandons the nest if the Ant does ; (5) that the Gamasids live upon friendly terms with the Ants; (6) that the Gamasids are not true parasites; (7) that they do not injure the Ants or their young; (8) that the Gamasids will eat dead Ants, and are probably either scavengers or messmates. -A communication was read from Mr. Edward Bartlett containing an account of the specimens of Rhinoceros from Borneo contained in the Museum of Sarawak.-A communication was read from Mr. T. T. Somerville, of Christiania, containing notes on the Lemming (Myodes lemmus).

Anthropological Institute, November 24.-E. W. Brabrook Vice-President, in the chair.-A paper on the perforated stones of South Africa, by H. Mitford Barber, was read.-An account of the Similkameen Indians of British Columbia, by Mrs. S. S. Allison, was read. The tribe at present inhabiting the upper valley of the Similkameen are immediately descended from a small band of the warlike Chilcotins, who established themselves in the upper valley of the river about a hundred and fifty years ago, and intermarried with the Spokans. They have much deteriorated, both physically and mentally, within the last twenty years, and are rapidly becoming extinct. The average stature of the men is about 5 feet 6 inches; their frames are lithe and muscular

and their movements quick and graceful. Their complexion is very light, and they have small hands and feet. The colour of their hair varies from jet-black to red-brown, and in some cases it is almost curly. They are born horsemen and capital shots. The sharp horns of the mountain goat were formerly fixed on shafts of hard wood and used as spears both in hunting and warfare; stone knives and hatchets were also used. The summer dwellings of the Similkameen Indians were made of mats of cedar bark, manufactured by the Hope Indians, which were thrown over a circular frame of poles. The winter houses were imply pits dug in the ground and roofed with poles and earth. All sickness was supposed to be the work of an evil spirit, who fastened on a victim and hung on, drawing away his life, until charmed away by the doctor, who worked himself into a state of frenzy, singing and dancing while he was trying to lure the evil spirit from his patient. Many of the medicine-men exercise strong mesmeric power over their patients, and they use several herbs as medicines; their panacea for all ills, however, is the vapourbath. When an Indian died he was laid out in state on a couch of skins; everything put on the body was new; his bow and arrows were laid at his side, along with his knife. His friends then assembled round him to feast, and when the feast was over his friends advanced, and taking his hand bade him farewell. Immediately after a funeral takes place the encampment is moved, lest the spirit of the deceased should revisit it. A widow or widower is forbidden to eat meat and certain vegetables for a month, and must wear quantities of spruce bush inside their shirts, next their skin. Cannibalism was never known among the Similkameens. In the mountain is a certain stone which is much venerated by the Indians, and it is said that striking it will produce rain. Polygamy was allowed, and if the husband and wife tired of each other, the price of the woman, or its equivalent, was returned by her father or guardian, and the parties were then free to contract another matrimonial alliance; but adultery, though it was generally compromised, was sometimes punished by cutting off the woman's nose or splitting her ears. Occasionally sick persons were buried before they were quite dead, and a good deal of infanticide was practised. The author has not found these Indians to be thieves, and gives them a general good character in other respects.

Geological Society, November 25.-Sir Archibald Geikie, F.R.S., President, in the chair.-The following communications were read-On the os pubis of Polacanthus Foxi, by Prof. H. G. Seeley, F.R.S. Hitherto the evidence of the systematic position of Polacanthus has not been very precise. The author has detected the missing pubis as an isolated specimen. This he regards as the anterior portion of the left pubis, and appends a full description of the bone. He furthermore gives a critical account of our knowledge of other pelvic bones of the genus, and is led to associate Agathaumus, Cratæomus, Omosaurus, and Polacanthus in near alliance, in the Scelidosaurian division of the Order Ornithischia.—A comparison of the red rocks of the South Devon coast with those of the Midland and Western Counties, by Prof. Edward Hull, F. R.S. The author believes, with Dr. Irving, that the red rocks of Devonshire are representatives of the Permian and Trias which occupy so large a portion of the district bordering Wales and Salop, and which extend into the Midland Counties, and comments on the remarkable resemblance between the representative beds on either side of the dividing ridge of Palæozoic rocks which underlies East Anglia and emerges beneath the Jurassic strata in Somersetshire. He believes that the breccia forming the hase of the series in the Torquay district is a representative of the Lower Permian division, but differs from Dr. Irving, in assigning the red sandstones and marls of Exmouth to the Trias, and not to the Permian as that author has done. He compares them with the Lower Red and Mottled Sandstones, and regards the Marls as of local origin, thus causing the beds to diverge from the normal type. The Budleigh Salterton Pebble-beds, with overlying sandstones and pebbly beds, he assigns to the horizon of the Pebble-beds of the Midland area, and points out that fossils of Silurian and Devonian types occur in the pebbles of both areas. The Upper Division of the Bunter is well shown at Sidmouth, and the author takes a calcareous breccia, two feet thick, which is found in the cliffs, as the basement-bed of the Keuper division.-Supplementary note to the paper on the "Red Rocks of the Devon Coast-section," Q.J.G. S., 1888, by the Rev. A. Irving. In this note the author accepts Prof. Hull's determination (see above) of the breccia at Sidmouth as the base

of the Keuper, and discusses the age of the sandstones containing vertebrate remains discovered by Messrs. Whitaker, Metcalfe, and Johnston-Lavis. He brings forward evidence in support of his view that these are really of Upper Bunter age, notwithstanding the character of the organisms. He adds new material in support of his contention that the sandstones and marls which Prof. Hull assigns to the Lower Bunter are really Permian; but he is inclined to think that the breccias (in part, at least) pass laterally into the sandstones, and do not underlie them. From this it follows that the break between the Permian and Trias of Devon is marked by the absence of the Lower Bunter of the Midlands, and the author quotes remarks of Mr. Ussher in support of his view that there is an unconformity at the base of the Pebble-bed. In conclusion the author refers to the difficulties of ascertaining the exact age of the breccias, and notes that we cannot prove that the highest Carboniferous beds are present in Devonshire. He observes that there is no valid reason why the great breccia-sandstone series of Devon should not be the true equivalent of the Lower Rothliegendes both in time and position in the sequence, and that some portions of them may be even older than the Rothliegendes of some districts. He discusses the evidence furnished by the igneous rocks, and points out the abnormal position both for the British and German areas which these would occupy, if the breccias were of Triassic age. The reading of this paper was followed by a discussion, in which Mr. H. B. Woodward, Mr. Hudleston, Mr. Topley, Prof. Boyd Dawkins, the President, Prof. Hull, and the author took part.

December 9.-Sir Archibald Geikie, F.R.S., President, in the chair. The following communications were read :-On the rocks mapped as Cambrian in Caernarvonshire, by the Rev. J. F. Blake.-High-level Glacial gravels, Gloppa, Cyrn-y-bwch, near Oswestry, by A. C. Nicholson (communicated by W. Shone). These gravels are found at Gloppa, and are situated at a height of from 900 to 1160 feet above sea-level, on the eastern slope of a ridge of Millstone Grit which forms the western border of the Cheshire and Shropshire plain. The beds present the slope. The gravels are in places much contorted, and falseappearance of having been abruptly cut off on the north-eastern bedding is frequent. They contain numerous striated erratics. Amongst the boulders are Silurian grits and argillites, granites like those of Eskdale, Criffel, &c., Carboniferous rocks, Lias shale, and Chalk flints. The shells are often broken, rolled, and striated, but the bulk of them are in fairly good condition. A list of the shells is given, including nine Arctic and Scandinavian forms not now living in British seas, nine northern types, species of ordinary British forms. also found in British seas, two southern types, and nearly fifty Comparative lists of the shells of Moel Tryfan and of those now living in Liverpool Bay are placed side by side with the list of shells from Gloppa. The reading of this paper was followed by a discussion, in which Dr. Hicks, Prof. Hull, Mr. Shone, Prof. Blake, the President, and the author took part. Some remarks sent by Mr. Clement Reid were read by the Secretary.-The subterranean denudation of the Glacial Drift, a probable cause of submerged peat and forest-beds, by W. Shone.

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Royal Microscopical Society, November 30.-Conver sazione.-There was a numerous attendance at this meeting, which passed off very successfully. The following objects and instruments were exhibited:-Megalotrocha albo-flavicans, by Mr. F. W. Andrew.--Foraminifera from the London Clay, by Rev. G. Bailey.—Amphipleura pellucida, Arachnodiscus Ehrenbergi, Polycystinæ from Barbadoes, a microscope with new substage focussing arrangement, by Messrs. R. and J. Beck.Foraminifera from the Chalk, by Mr. E. T. Browne. -Hyaline Foraminifera from the Folkestone Gault-viz. Vitriwebbina Sollasi, n. sp. (Chapman), V. lævis, Sol., Polymorphina Orbignii, var. cervicornis (Chapman), by Mr. F. Chapman. --A thickened nodule of Nitella translucens, by Mr. E. Dadswell.Volvox and Batrachospermum in saturated solution of common salt; diatom structure in medium (Br Ant1, Br Ars1, Piperine,), by Mr. J. E. Ingpen.-Filaria sanguinis hominis (diurna and nocturna), prepared by Dr. P. Manson; Bacillus anthrax in lung; microscopes with new focussing arrangement to substage, by Messrs. Johnson.-Epistylis flavicans, Lophopus crystallinus, Argulus foliaceus, by Mr. R. Macer.-Transverse section of fertile head of Equisetum arvense showing spores and elators in situ, section of Pilia grandiflora showing reticulate and pitted cells, by Mr. G. E. Mainland. -Hoplophora carinata v. pul