ÆäÀÌÁö À̹ÌÁö
PDF
ePub

prepared surface, there is no indication of the activity of the chemical rays suffering any diminution, but, on the contrary, at these altitudes they are not so liable to b affected or absorbed by transmission through dense air and other media. A further illustration of this fact may be gathered from the statements published many years ago by Mr. Crookes, to the effect that the prismatic spectrum was of greater length and purity, and that the more refrangible solar rays were better defined optically, and endowed with greater photographic activity, at noon on a fine Midsummer day than at any other season of the year; this result being the necessary consequence of their more perpendicular passage at this time through the earth's atmosphere. If now the experimental observations of Mr. Glaisher be considered in connection with the well-known fact that photographic papers lose much of their sensitiveness when deprived, by the action of heat or desiccating substances, of the greater part of their hygroscopic moisture, the interesting announcement of that gentleman may be regarded as furnishing from external nature a confirmatory illustration of this truth, and not be evidence of a notable diminution in the chemical activity of the sun's rays at these great altitudes.

PHYSICS.

[ocr errors]

R. W. A. MILLER has been examining the spectrum of thallium, under the influence of a progressively-increasing temperature. It is well known that when thallium is examined in the ordinary way it exhibits in the spectroscope only a single green line of intense brightness. Dr. Miller found that on employing the flame of burning hydrogen, and then of the oxyhydrogen jet, as the temperature increased the brilliancy of the green line also increased, but no new lines made their appearance; but on employing two stout thallium wires as the electrodes of a strong induction coil, by which means a still higher degree of heat was obtained, several new lines which were proved to belong to the metal appeared. In addition to the intense green line, the spectrum contains several very characteristic groups of lines, somewhat similar to those of the spectra of cadmium and zinc, and in a less degree like that of lead.

MM. P. Christofle and F. Beilstein have been examining the spectrum of phosphorus and the coloration of the hydrogen flame by phosphorus and its compounds. A very small quantity of phosphorous acid communicates a beautiful green colour to the hydrogen flame. On examining by means of a spectroscope the flame of hydrogen into which either this substance, phosphorus, or hypo-phosphorous acid was introduced, two beautiful green lines, and a third a little less vivid, appeared. From the extreme sensibility of this method, and the exact results obtained, it is evident that the process may be used for detecting phosphorus in cases of poisoning.

Mr. Gassiot exhibited, at a recent soirée of the Royal Society, a very powerful spectroscope, with nine glass prisms. It showed the yellow sodium line double, the two portions appearing about a quarter of an inch asunder.

Kirchoff has published in the "Philosophical Magazine" for April "Some Contributions toward the History of Spectrum'Analysis,” in which he reviews the parts taken by various investigators in the development of this subject. In the same number is a short note by Dr. Roscoe, "On the Spectrum produced by the Flame evolved in the Manufacture of Cast Steel by the Bessemer Process." The author expresses his belief that this first practical application of spectrum analysis will prove of the highest importance in the manufacture of cast steel by this method.

Dr. Joule also describes a new and extremely sensitive thermometer. He states that it is able to detect the heat radiated by the moon. The instrument consists of a vertical glass tube, two feet long and four inches wide, closed at the bottom end, and divided longitudinally by a blackened pasteboard diaphragm, leaving a space at each end about an inch in length. A magnetized sewing-needle is suspended over the edge of the division at the top. The slightest excess of temperature of one side over that of the other occasions a circulation of the air up one side and down the other, which in doing so moves the index.

Mr. G. Gore, of Birmingham, has produced a new and simple furnace capable of smelting cast-iron, copper, gold, &c., without the aid of a bellows or lofty chimney. Its heat is generated by ordinary coal-gas and atmospheric air; its consumption of gas is from 30 to 40 cubic feet per hour; "it has smelted five ounces of copper in four and a quarter minutes, and is capable of fusing half a pound of copper or six ounces of castiron;" its size is about that of a Stilton cheese; and it possesses the valuable qualification of continuous access to the contents of the crucible for any length of time without oxidizing it or materially lowering its temperature; the crucible may also be removed or a fresh one introduced without interfering with the action of the furnace.

Some additional experiments "On the Motion of Vapours towards the Cold" is given by C. Tomlinson in the May number of the "Philosophical Magazine." They consist of a few of the subsidiary facts observed during his previous inquiry, which we have already noticed in a previous number of this REVIEW.

Mr. W. R. Grove, F.R.S., has recently delivered a lecture to the Chemical Society, "On the Action of Heat upon certain Fluids." His observations had reference more particularly to the bumping action observed whilst boiling water which has been deprived of its dissolved air. We know that if water has been deprived of air by means of an air-pump, or by means of longcontinued boiling in a vessel with a very narrow mouth to exclude the atmosphere, the application of heat is not attended by constant and regular ebullition as when water is boiled in a wide open vessel, but the water is for a short time quiescent, and then suddenly at intervals evolves explosive bursts of steam; and a thermometer immersed in the water shows a variable temperature, hottest just before an explosion and least hot immediately after. A consequence is that no one has yet been able to observe the true boiling-point of water.

The lecturer found that on boiling ordinary water, air containing a slightly increased proportion of oxygen was first driven out; the proportion of oxygen then gradually diminished until pure nitrogen was expelled.

But he had not succeeded, even on boiling nineteen out of twenty parts of the water away, in expelling the whole of the nitrogen. Water that has been so boiled rapidly absorbs air again. His general conclusions were, that water has a very powerful affinity for the gases of the atmosphere, and especially for nitrogen; that by several processes the oxygen may be removed from water, but the nitrogen resists all efforts at separation, and therefore it is doubtful if absolutely pure water had ever been prepared ; and that ebullition in water consisted in the production and disengagement of bubbles of steam formed upon a nucleus of a permanent gas.

Several letters to and fro, between Dr. Tyndall on the one hand and Professors Thomson and Tait on the other, respecting the manner in which Dr. Tyndall has treated the claims of Dr. Joule of this country in the subjects of heat, &c., versus those of Dr. Mayer on the Continent, have been published in recent numbers of the "Philosophical Magazine," and reach their climax in the number for June, in which Dr. Thomson declines to take part personally in any controversy with Dr. Tyndall.

Dr. Matthieson and Dr. Vogt have examined the influence of temperature on the electric conducting power of thallium, and find that thallium decreases in conducting power about 31 per cent. between the freezing and boiling points of water.

99 66

The Rev. N. Callan describes in the June number of the "Philosophical Magazine " an induction coil of great power." With this coil he has obtained electric sparks "fifteen inches" in length. This, if we recollect rightly, is less than that obtained by Mr. Siemens with his large induction coil exhibited at one of the soirées of the Royal Society, and described in a previous number of this Review. The length of wire in the secondary circuit of Dr. Callan's coil was "150,000 feet."

66

Mr. W. Ellis has published in the "Philosophical Magazine" for May an account of some experiments he has been making on the change of rate produced in a clock by a particular case of magnetic action." He describes the different conditions under which the clock was retarded or accelerated by the influence of approximated magnets.

A paper by Dr. Angus Smith has been read before the Royal Society, "On the Absorption of Gases by Charcoal." He has found that charcoal absorbs oxygen so as to separate it from common air, or from its mixture with hydrogen or nitrogen at common temperatures, and that it absorbs it for at least a month, rapidly at first and slowly afterwards. It does not absorb hydrogen, nitrogen, or carbonic acid for the same period. Water expels mercury from the pores of charcoal by an instantaneous action.

Mr. Hunter, of Queen's College, Belfast, has also been experimenting in the same subject. He finds that logwood charcoal absorbs the most ammonia, fustic charcoal most carbonic acid, and ebony charcoal most cyanogen.

ZOOLOGY.

Speries of Rhinoceros.- Mr. Blyth has been at great pains to examine into the statement of Helfer, that the three known species of Asiatic 2 R

VOL. II.-NO. VIII.

rhinoceros inhabit the region of Burmah. He succeeded during his travels in that country in confirming the existence of the one-horned Rhinoceros Sondicus, and the two horned Rhinoceros Sumatranus, but believes that these two insular species are the only ones of the Indo-Chinese region; the third species, Rhinoceros Indicus, appears to be peculiar to the region at the foot of the Himalayas, and the province of Assam.

The Moa.-A letter from Mr. E. L. Layard, Secretary to Sir George Grey, Governor of New Zealand, states that two species of this bird have been found to maintain a lingering existence in that region. Of one species of comparatively small size (about 3 feet high) a specimen has actually been killed and eaten by a party of explorers, and fifteen others seen. Of the other species, one of the large Moas, the fresh footsteps, fifteen inches long, have been traced, as Mr. Layard states, by a party who had lost themselves. Both these living species inhabit the little explored Middle Island, never thickly peopled, and nearly depopulated about thirty years since. It is suggested that although tradition points to the recent existence of the Moa, and there are no large animals capable of having exterminated it, the prevalence of bush fires may have had that effect. The probability, however, is that it still exists in some of the untrodden tracts of the Middle Island.

Pulsations of the Heart in Quadrupeds.—In a recent lecture at the Royal Institution Professor Marshall stated that by an ingeniously contrived apparatus, he found the pulsations to increase in frequency as the size of the animal diminishes. Thus in the horse they number 55 per minute; in man 72, in the dog 96, in the rabbit 220, and in the squirrel 300. But whatever the size, the number of beats required to complete the circulation throughout the whole body averages 27; and the proportion of the weight of the blood to that of the whole body is 1 to 12.

Tooth-billed Pigeon.-This bird (Didemculus strigirostris), of so great interest as being believed to be the nearest ally of the Dodo, has been discovered to be not quite extinct, as was believed. Mr. Williams, Consul for the Navigator Islands, after several years of unsuccessful efforts, has managed to procure a single living example. A person who visited the Navigator Islands in November last ascertained that, although the bird is now totally extinct at Upolu, a few are still to be found on the island of Sawaii, the largest and most mountainous of the group, and exertions are being made to secure a specimen for the gardens of the Zoological Society.

Struggle for Life.-The Royal Commissioners for inquiring into the operation of the laws relating to the herring fisheries, state that the take of herrings by fishermen within the jurisdiction of the Scotch Fishery Board amounted in 1861 to nearly 900 millions. It is very common to find a codfish with six or seven herrings undigested in his stomach. If we allow a cod only two herrings a-day, and estimate that he feeds on herrings for only seven months in the year, he takes 420 as his allowance during that time; and since at least 2,400,000 codfish were caught in 1861, and the cod and ling caught were certainly not a tithe of those left behind, the destruction of herrings by them alone may be estimated at ten times as great as that effected by all the fishermen put together. The Commis

sioners add: "A plentiful supply of herrings in any year nourishes an increased army of enemies; and if these latter multiply too fast, the herrings become diminished in number, whereupon the fish that destroy them are starved down, and in a weakened state more easily fall a prey to their own enemies. The herring, then, relieved from their oppressors, in a year or two appear again in immense numbers, and so the alternations of prosperity and panic in the trade which they originate will occur with as much regularity as if the herrings were manufacturers."

Frogs v. Fishes.-The Imperial Court of Montpellier have just decided on an appeal in which the point in dispute was whether a frog is a fish. The judgment was affirmative; and those persons who have hitherto thought that they might catch frogs at all seasons in private or public waters now find that they were mistaken.

Sun-Birds and Humming-Birds.-Mr. Wallace, who has had ample opportunities of observing these birds in a state of nature, and has carefully examined into their relationship, declares that no true affinity exists between the sun-birds (Nectarinide) and the humming-birds (Trochilida). The sun-birds are a specialized form of an extensive group of typical perchers (Passeres). The latter are essentially of the character of swifts, profoundly modified for an aërial and flower-frequenting existence, but still bearing in many important peculiarities of structure unmistakeable evidence of a common ancestry. Hitherto these families of birds have been considered as bound together by the closest family relationship, the sun-birds sucking the nectar of flowers by means of a tubular retractile tongue.

New Insect Pest in London.—Mr. E. Newman calls attention to a new insect infesting the Friends' Institute in Bishopsgate-street. He observes that there are two well known to every one-viz., the cockroach and the cricket; but this is a novelty, to which he has given the name of Lepismodes inquilinus. It is half an inch long in the body, and the antennæ and tail are also each half an inch in length, so that the whole length of the insect is an inch and a half. It is nocturnal in its habits, and chiefly infests the dining-room, but is frequently caught, from the fact that its feet being non-prehensile it slides down the smooth sides of saucers and basins, &c., and is unable to escape again.

Neuter Ants.-M. Charles Lespés has obtained some singular results from an investigation into the rudimentary reproductive system of neuter ants. He finds that ants do not seek aphides indiscriminately, but that each species seems to have its particular favourites; and in the same manner, those which bring up the larvae of coleopterous insects, for example, Claviger, select certain species for their attentions. He also finds that all neuters have the rudiments of ovaries, developed in a very different manner in different species; and that many have two forms of neuters which sometimes pass insensibly into each other, and are sometimes divided by sharp lines of distinction, forming data for classification.

Aquatic Hymenopterous Insects.—A second species of these remarkable insects has been found by Mr. Lubbock, and named Walkeria aquatica. It swims, not by means of its wings, as Polynema natans, but holds its wings motionless under water, and uses its legs only, though these are

« ÀÌÀü°è¼Ó »