of the larva." This formation finally becomes the jointed stem of the pentacrinoid stage. "After swimming freely for a time, averaging from eight hours to a week,' the larva becomes sluggish, and its form is distorted by the growing crinoid." The mouth and alimentary canal of the larva disappear, the stem lengthens, the rudimentary arms are seen, and at some stage of this process the creature becomes attached. Further details in Proceedings of the Royal Society, Vol. xii., No. 54, p. 426.

ARTIFICIAL PRODUCTION OF FIBRIN FROM ALBUMEN AND GLUTEN.-The Proceedings of the Royal Society, No. 52, contain an important paper by A. W. Smee, jun., on the above subject. He finds that fibrin can be produced by the direct action of oxygen on albumen, and that "gluten dissolved in gastric juice, and then oxidised at the ordinary temperature, yields fibrin."

78TH PLANET.-Astronomische Nachrichten, No. 1408, contains a letter from Dr. R. Luther, of the Bilk Observatory, announcing the discovery by him, on the 15th of March, of the 78th planet, which he names Diana. It is of the 10th magnitude.

MORE COMPANIONS OF SIRIUS.-M. H. Goldschmidt informs the French Academy that he has been able to see Alvan Clark's companion of Sirius, at intervals, with a telescope of 46 lines aperture. He also observed several other minute stars from 15" to 1' from Sirius. One of these, which he says is without doubt a companion, is south of that discovered by Clark: angle of position, 95°—97°. This he found visible " pour moments." A second star on the line between Sirius and A. Clark's companion, was an almost imperceptible point of light. East of Sirius, and of companion No. 1 F, he finds another little star, No. 3 D; and he adds, "the star, No. 4 E, has an angle of position of 170°, and No. 5 of 25° to 30', and are distant from Sirius in the proportion of (par rapport de) No. 1."

STAR SPECTROSCOPES.-' -The Astronomische Nachrichten, No. 1408, contains a description of an apparatus made by Steinheil for examining and measuring star spectra, which appears more convenient than that of Jansen used by Secchi. One of the new pattern was forwarded last autumn to the Hon. G. Lettsom, British Envoy at Monte Video. Two other spectroscopes are described in Cosmos, which offer the advantage of direct vision. The one, used by Amici in 1860, composed of two prisms of crown glass, having one prism of borosilicate of lead between them; the other made by M. Hoffman, of several prisms of flint glass, compensated by several prisms of crown.

LARGE CONCAVE MIRRORS.-In the Supplement to the Practical Treatise on Optical Instruments, by Andrew Pritchard, published in 1850, it is stated that a burning mirror was exhibited to the British Association, formed of a circular pane of plate-glass, three-sixteenths of an inch thick, and three feet and a-half in diameter. This was fitted to a cast-iron box one inch deep. Air was extracted from the box, and the atmospheric pressure on the glass pane gave it the necessary curvature, and it was then able to reflect and converge enough heat to ignite various articles and roast meat. Such a mirror, silvered by Liebig's process, as in telescope mirrors, might be useful for many scientific purposes, as, for example, experiments on the heat of the moon.

PHYSIOLOGY OF THE STOMACH.-Dr. Pavy gives a simple physical reason why the stomach is not destroyed by the solvent power of its own gastric juice. He says that in a state of health the blood is always alkaline, and the gastric juice acid. The introduction of food into the stomach causes an influx of blood to that organ, as well as determines a secretion of gastric juice, and he conceives that the alkalinity of the former fluid protects the stomach from the action of the latter.

BLACK RAIN IN SCOTLAND.-On March 14, at half-past eight p.m., black rain fell at Blackford, near Auchterarder, Perthshire. A minute quantity of the deposit, dried on a microscopic slide, exhibits a few angular silicious particles, a multitude of exceedingly small dark particles, without structure, and some fibres of vegetable appearance, but nothing distinctive that we could make out.