Radiant Points Research Articles

Scientific Serials

American Journal of Science and Arts, June.—Reviewing what is now known of extra digits in the feet of the modern horse Prof. Marsh says the instances fall naturally into two groups: the first comprising simply cases of reduplication (like that of the occasional extra-finger in the human hand), not satisfactorily explained as yet; the second includes cases where a true digit is formed, the component bones in normal position and relation, and such instances seem clearly due to reversion to some ancestral type. Extra digits appear more frequently on the fore feet than the hind feet (as a study of fossils would lead one to expect), and more frequently on the inside of the main digit, the outer splint remaining rudimentary (this, again, is opposed to the general law of reduction in the ungulate foot).— Mr. Sargent's paper on the forests of Central Nevada has been elsewhere referred to, and we further note that Prof. J. C. Draper writes on the dark lines of oxygen in the solar spectrum on the less refrangible side of G (in the regions about λ 4317 and λ 4319); Mr. Christy seeks an answer to the question “Are cinnabar deposits produced by sublimation, or are they deposited from solution?” and concludes that they are the immediate result of the action of solutions of alkaline carbonates containing also alkaline sulphides; Mr. Hodges suggests a new absolute galvanometer.—Mr. Sawyer contributes a first catalogue of radiant points of meteors (from observations at Cambridge during the last two years); and Maria Mitchell notes on the satellites of Saturn.—A recent paper published in Brazil, by Mr. Derby, on the geology of the Lower Arizonas, is summarised by Mr. Rathbun.

First catalogue of radiant points of meteors

First catalogue of radiant points of meteors

Meteor showers visible during August 6–12 with radiant points eastward of the perseids (R A. 44°, dec. 56° +)

Meteor showers visible during August 6–12 with radiant points eastward of the perseids (R A. 44°, dec. 56° +)

July Shooting Stars

I OBSERVED 197 shooting-stars in July—nearly all of them between the 6th and 20th—in twenty-four hours of watching. The weather was generally very cloudy and stormy between the 13th and 23rd, or many more would have been seen. I looked usually towards the eastern sky, and from the considerable number of meteor paths registered, am enabled to give the following table of radiant points visible in that quarter during the period of my observations. The list may be considered very fairly complete and accurate, for the great majority of the meteors were well seen, and many of them had short courses evidently near their radiant centres:—

On the Structure and Origin of Meteorites 2

THE study of meteorites is naturally divisible into several very distinct branches of inquiry. Thus in the first place we may regard them as shooting stars, and observe and discuss their radiant points and their relation to the solar system. This may be called the astronomical aspect of the question. Then, when solid masses fall to the ground, we may study their chemical composition as a whole, or that of the separate mineral constituents; and lastly, we may study their mechanical structure, and apply to this investigation the same methods which have yielded such important results in the case of terrestrial rocks. So much has been written on the astronomical, chemical, and mineralogical aspect of my subject by those far more competent than myself to deal with such questions, that I shall confine my remarks almost entirely to the mechanical structure of meteorites and meteoric irons, and more especially to my own observations, since they will, at all events, have the merit of greater originality and novelty. Time will, however, not permit me to enter into the detail even of this single department of my subject.

Radiant points of Shooting stars

IN December, from observations of 163 shooting stars seen in 20½ hours' watching, chiefly in the evenings, I amply confirmed several of the positions of radiant points as given in my note (NATURE, vol. xv., p. 158), and observed that several of the showers there mentioned were actively continued. The centres, as I gave them, of two of these require revision, as the additional meteors seen in December indicate the radiants with greater precision than the few I had noted in November. The new radiant in Sextans, I now deduce at R. A. 148°, Decl. 2° N., and that at τ Leonis, as near Crater R. A. 165°, Decl. 6° S. The meteors from these new showers are very rapid and white, usually leaving bright streaks for 2 or 3 secs, in their path.

Radiant Points of Shooting Stars

IN December, from observations of 163 shooting stars seen in 20½ hours' watching, chiefly in the evenings, I amply confirmed several of the positions of radiant points as given in my note (NATURE, vol. xv., p. 158), and observed that several of the showers there mentioned were actively continued. The centres, as I gave them, of two of these require revision, as the additional meteors seen in December indicate the radiants with greater precision than the few I had noted in November. The new radiant in Sextans, I now deduce at R. A. 148°, Decl. 2° N., and that at τ Leonis, as near Crater R. A. 165°, Decl. 6° S. The meteors from these new showers are very rapid and white, usually leaving bright streaks for 2 or 3 secs, in their path.

Radiant-Points of Shooting Stars

IN December, from observations of 163 shooting stars seen in 20½ hours' watching, chiefly in the evenings, I amply confirmed several of the positions of radiant points as given in my note (NATURE, vol. xv., p. 158), and observed that several of the showers there mentioned were actively continued. The centres, as I gave them, of two of these require revision, as the additional meteors seen in December indicate the radiants with greater precision than the few I had noted in November. The new radiant in Sextans, I now deduce at R. A. 148°, Decl. 2° N., and that at τ Leonis, as near Crater R. A. 165°, Decl. 6° S. The meteors from these new showers are very rapid and white, usually leaving bright streaks for 2 or 3 secs, in their path.