Popular Science Monthly/Volume 46/December 1894/Notes
It is the habit of centipeds to carry their young, clasped by means of their legs, to all parts of the under side of the body, though generally the young are clustered in dense masses. When the young are thus bunched together the body is coiled upon itself at that part; and the contrast between a centiped in this position, says Mr. J. J. Quelch, who describes the centiped's method in Nature, and a scorpion carrying her young upon her back, just as a small opossum does, is a very marked one.
The sumpitans or blowpipes of the Jakuns living on the Serting River in the sultanate of Johore are manufactured from a very long-jointed, straight variety of bamboo, which is generally carved and traced with many rude devices. The darts consist of thin splinters of wood about a foot long, having a plug of pith at the blunt end. The point is as sharp as a needle, and is covered with a black, resinous substance, which is in many cases extremely poisonous. Monkeys and other small animals die from its effects almost immediately; on man and the larger animals its action is less rapid, but quite as deadly. The poison is known to the Malays as ipoh.
An active discussion was had in the British Association on the question of the criterion by which a flint should be regarded as the work of man or of Nature. With regard to the ruder forms of what some extreme anthropologists include among Palæolithic implements opinion was much divided; as it was also on the point as to how far the position in which such implements, even when recognized as artificial, are found can be accepted as an indication of their age. The moral suggested by the discussion is that many flints have been accepted as the handiwork of man on the most inadequate evidence, and that there is still much doubt as to whether man existed in the British islands in preglacial times.
Photographic records taken with the aid of the capillary electrometer of electric currents produced by speaking into the telephone were exhibited by Mr. Burch in the British Association. The letter z produced a complicated curve in which oscillations of current lasting only one three-thousandth of a second were visible with a lens. The speaker said that the electromotive force produced in using the ordinary telephone amounts to about one tenth of a volt; but with emphatic syllables it may rise high enough to produce electrolysis.
The question whether the intensity of the radiation of heat by the sun is affected by its condition as to spots has been studied by M. R. Savelief, of Kiev, in the light of observations made in the spring and the fall of the years 1890, 1891, and 1892. The results point to an affirmative answer, the radiation being greater as the sun-spot activity augments. A variation in one series of the experiments is interpreted as indicating that the increase is dependent, not so much on the absolute number of the spots as upon the intensity of their evolution; or it may mean that it is immediately consecutive on their diminution. The meeting of the British Association at Oxford was attended by 2,311 persons, several hundred more than attended last year's meeting; and the receipts were £2,175. Appropriations of £1,100, or about £100 more than usual, were made for grants for research. The committee of recommendations proposed that Section D be called zoölogy instead of biology; that a separate section be constituted for botany; and that Section I consist of physiology with experimental pathology and experimental psychology.
The results of certain experiments concerning the effect of various forms of distraction upon memory, reported by W. G. Smith to the British Association, show that the memory is most efficient when the subject is allowed to learn various combinations of the alphabet without distraction of any kind. But the power of recollection is lessened to some extent by regular movements of the forefinger made by the subject while he is learning; still more by the simultaneous articulation of an unintelligible syllable; and most of all by the performance of simple addition during the experiments.
The committee of the British Association on an International Standard for the Analysis of Iron and Steel has reported, through Prof. W. C. Roberts Austin, that the composition of the remaining, before undetermined standard, No. 5, has now been determined by four different analysts, and is accurately ascertained. The standards will shortly be deposited with the Board of Trade, when the work of the committee will have been completed.
A museum of journals at Aix-la-Chapelle, Germany, founded in 1886 by M. Oscar Forkenbeck, is said to contain already five hundred thousand journals in all languages. The founder devoted his whole fortune for forty years to the acquisition of rare and curious specimens, and to subscriptions to journals in all parts of the globe. He received and read every day a considerable number of papers in thirty different languages. Having started the museum with ten thousand full collections, he addressed a circular letter to the press of the globe asking co-operation in his enterprise, and a large number of journals responded favorably.
In certain experiments made by him, Mr. L. Cobbett found that tissues which had once been the seat of erysipelas retained the power of reacting more energetically than normal tissues when inoculated with the sterilized products of cultures of the erysipelas organism. He suggested that immunity might be explained as being due to an ability on the part of the tissues to react to chemical substances produced by bacteria.
Sir John Murray reports that the study of the weather at Ben Nevis and Trieste has led to the isolation of two types of weather—namely, perfectly clear days and those on which some fog exists. The two types correspond to quite different characters in the houi'ly variation of temperature and pressure.
An extraordinary migration of "Croton bugs" was described by L. O. Howard in the American Association as witnessed by him in Washington one very dark day last summer. The migrating army, composed of many thousands of individuals, consisted almost entirely of female roaches carrying egg-sacks. An investigation of the circumstances led him to the conclusion that the observation indicated a development of the true migratory instinct, and that while the old residence of the insects might have supported its then occupants, provision for the sustenance of the young, as yet unborn, necessitated a journey in search of new quarters. The migration of this army upon a dark day suggested that it is by similar expeditions after nightfall that new houses become infested with roaches.
Aluminum has the property, when used as a pencil, of leaving an indelible mark on glass or any other substance having a siliceous base. A deposition of the metal takes place, and, while this may be removed by a suitable acid wash, the mark itself can not be removed by rubbing or washing. Magnesium, zinc, and cadmium have a similar property, but the mark of magnesium is easily removed, the application of zinc requires a wheel, and zinc and cadmium tarnish; while aluminum is permanent and remains bright. This property is susceptible of a variety of practical applications in decorating glass.
In his address before the Section of Geology of the British Association Mr. L. Fletcher suggested the importance to a highly civilized country of having within its own borders men who would make themselves familiar with all that was being done and had been done in the subject, would do what was possible to fill up the gaps in the science, and would make the results available for those who had not the opportunity to make so complete and original a survey for themselves. He recommended that by some means each university should be enabled to endow a professorship of mineralogy in such a way as to attract the most capable men to the study of the subject; and he pointed to the example lately set by Cambridge, which encouraged the students of physics, chemistry, and geology to acquire a knowledge of mineralogy and crystallography, and gave them credit for that knowledge in the examination for a degree.
As a result of elaborate investigations, Dr. J. S. Haldane has come to the conclusion that in colliery explosions the deaths from suffocation are due, not, as is generally supposed, to carbonic-acid gas, but to the preponderance of nitrogen and the deficiency of oxygen. Life could be saved if the colliers could be supplied with oxygen for an hour or so; and the author has devised an apparatus for enabling a man to breathe oxygen, of which sixty litres are compressed into a half-litre bottle, with tube and regulating taps, supplemented by a wire compress for the nose to prevent breathing through that organ.