seen at Starfield, I have never obtained a single glimpse of the division in the ring C, seen and measured micrometrically by M. Otto Struve, nor of the ring being concentrally divided into two, as seen by Mr. Dawes. On every occasion, and when most sharply defined, it appears of one uniform texture and depth of shade, constantly conveying to my mind the idea of network on a crape veil, as I originally described it."

A curious observation by Mr. Carpenter, of the Royal Observatory, Greenwich, may be noticed here. It was made on the evening of March 26, 1863, and consisted in a "great increase of brightness of the dusky ring, which appeared nearly as bright as the illuminated ring, and might easily have been mistaken for a part of it."

The boundaries, changes, division, and amount of transparency of the dusky ring, also the division of the exterior bright ring, are matters calling for further examination by those observers who are provided with good instrumental means. With regard to the rings generally, Sir John Herschel remarks that all indications from observation point to a vaporous constitution. Physical considerations also make this probable, and "it is very possible that the rings may be gaseous, or rather such a mixture of gas and vapour as consists with our ideas of a cloud."*

OCCULTATIONS OF STARS BY THE MOON.-Only one of these is visible in the evening, that of k Virginis, a star of the 6th magnitude, on the 6th day of the month. Disappearance, 10h. 35m.; reappearance, 11h. 30m.; angular distance from the vertex to the right hand in inverting telescope, 9° and 281° respectively. Whilst this star is behind the Moon, another of nearly equal (64) magnitude, 46 Virginis, will just escape occultation on the other side of the Moon, her limb passing, about 11h. 10m., within a very short distance of it.

THE MOON.-The phases of the Moon, with notices of those regions of her surface, which will be at different times under or near the terminator, we have this month thrown into a tabular form. No new feature of particular interest has, so far as we know, been brought to light since the date of our last "Notes."

April 1. Plato, Eratosthenes, Mare Nubium.

2. Mare Imbrium, Copernicus, Bullialdus.

April 8, 9. Mare Crisium, Mare Fœcunditatis.

دو

14. Last Quarter at 10h. 35m. P.M.

22. New Moon at 8h. 20m. P.M.

,, 25, 26. Mare Crisium, Mare Fœcunditatis.

27. Posidonius, Mare Tranquillitatis, Theophilus.
28. Mare Serenitatis, Maurolycus.

29. First Quarter at 6h. 18m. P.M. Archimedes, Hipparchus. 30. Mare Nubium.

APRIL METEORS.-An interesting group of meteors has established a claim to consideration for this month. Not long after the remarkable fact was proved, that the August and November groups move in orbits nearly coincident with those of two small comets, it was noticed, by Drs. Weiss and Galle, that the April meteors also followed nearly the path of a comet, known as I. 1861, which was discovered by Mr. Thatcher, of New York, and is supposed to have a period of 415 years.* But as the observations of that group were not very numerous, it was desirable to procure, if possible, some confirmation of this.

Last year, however, little additional information was obtained. Indeed, the only observations we have met with were made by Professor Karlinski, of Cracow, who saw nineteen meteors, chiefly of the first or second magnitude, between midnight on April 20, and three o'clock on the following morning. Of the nineteen, sixteen appeared to belong to the group, and they gave a radiant point, agreeing well with the observations of former years, at about R.A., 18h. 0m., N.P.D., 55°, or very near the constellation Lyra. If we assume that the earth crossed the orbit of the meteors last year about two o'clock Cracow, or one o'clock Greenwich, time, on the morning of April 21, it will follow that we shall this year cross it about seven o'clock on the morning of April 20. This may be somewhat in error, and it will be advisable to keep up a watch for a few hours before daylight on that morning, in the hope of observing a few meteors of the group, and improving our knowledge of its orbit.

THE NEBULA OF ORION.-An interesting paper by Professor D'Arrest has recently appeared in the "Astronomische Nachrichten," on the great nebula of Orion, which it seems desirable to give some account of here. He states that in the disputed question as to changes which have been said to have taken place in the See a paper by myself in the "Proceedings of the Meteorological Society," for 1867, April.

appearance of the nebula, a drawing made by Lefebvre, Professor of Physics at Lyons, in the year 1783, and published at Paris in the 22nd volume of "Rozier's Observations," has been overlooked. An examination of it throws doubt upon several of the supposed changes, as it delineates the parts of the nebula to which they refer in a manner very similar to that of the latest drawings of Bond and Struve. So that the variability would appear to be limited to some temporary changes of light at some nodal points, and the greater or less visibility of the faint patches of light which fill up some gaps, such as the Sinus Lamontii. The question of these changes has become of great interest since Mr. Huggins's prismatic analysis of the nebula has shown that it possesses a gaseous constitution. The variability of the faint stars within the trapezium appears to be well established. But further observation of the light of different parts of the nebula itself are very desirable. D'Arrest gives in the same paper some observations made by him of the branches of nebulous matter which connect the great nebula about Orionis with the smaller masses on each side of it, about and c Orionis. Thus and are connected by a double branch, and @ and c by a threefold branch. The system evidently extends still farther. But the examination of these minute points is very laborious, and can only be pursued on very favourable nights, and with very powerful object-glasses. Some of the branches mentioned were observed also by G. P. Bond, but were not figured by him, owing to his death shortly afterwards, which, it will be remembered, took place early in 1865, before he could receive the medal of our Astronomical Society, which had been that year awarded to him, in recognition of his important observations and discoveries.

THE NACHET ROTATING STAGE FOR THE
MICROSCOPE.

AT one of the meetings of the Royal Microscopical Society last year, Dr. Carpenter exhibited a binocular microscope, by Nachet, fitted with a rotating stage, which he highly commended. Acting upon Dr. Carpenter's advice, Mr. Henry Crouch (of London Wall), adapted this form of stage, with a slight improvement in its construction, to the instrument which he calls his "Cheap Binocular."

The Nachet rotating stage is very similar to the excellent pattern which the late Richard Beck-to whom microscopy was so

deeply indebted-constructed for his well-known "Popular Microscope," but it differs in some particulars. The accompanying sketch will render its construction and action intelligible. C is a plate of thick black glass, set in a brass circular frame, with a milled edge. A slight pressure upon the milled edge causes the

plate and object to rotate very smoothly and concentrically with the optic axis of the instrument. The object-holder is formed of another piece of smooth polished black glass, (E), carrying a brass frame on which the object is laid. Two brass springs, d d, with smooth ivory points at their extremities, press the glass plate, E, against the stage plate, C, with sufficient force to keep it steady when carrying ordinary objects or apparatus. The two upright brass handles enable the plate, E, to be slided in any direction with a very equable and agreeable motion, and with sufficient adhesive resistance to ensure steadiness. The extent of motion is determined by the brass frame of the plate, E; the motion stops as soon as the ivory points come into contact with the frame in any direction. The amount of motion is abundant for slides, etc., but is not quite enough when zoophyte-troughs are used. While, therefore, tho'roughly agreeing with Dr. Carpenter in estimating very highly the convenience of this kind of stage, we have suggested to Mr. Crouch the propriety of adding a trough-holder, which will very slightly increase its expense.

We congratulate Mr. Crouch upon having now produced one of the most complete and scientifically constructed of the cheap microscopes. He has done well in adapting it on Beck's plan to

carry all the illuminating apparatus usually required, and in providing it with the universal screw.

Ross's new instruments and apparatus fit the same guage as Beck's. Crouch wisely takes the same sizes, and we hope soon to have an universal guage for apparatus as well as for the screws attached to powers.

NOTES FROM PROFESSOR HUXLEY'S LECTURES AT THE COLLEGE OF SURGEONS.

:

BY E. RAY LANKESTER.

We have heard some persons ask, "What is the good of attending lectures? Cannot you learn everything you will hear much more effectively by reading at home?" In very many cases, no doubt, it is true that lectures are not what they should be; but such lectures as those which a master in science can give are worth many books. It is because Professor Huxley possesses two great qualifications that his lectures are now so numerously attended, and so deservedly esteemed he is a most original thinker and brilliant observer, and perhaps what is more important, he keeps himself thoroughly acquainted with the work done in his departments of science in Germany, France, and elsewhere, and thus is able to give in his lectures the latest results of thought. It would be impossible, in a brief space to give a report of the lectures which Professor Huxley has delivered this spring at the College of Surgeons on the Invertebrata, but we may notice a few points of novelty or interest which have been discussed. The Invertebrata are regarded by Professor Huxley as very sharply cut off from the Vertebrata. There are no links which connect the two in any way; the bi-cavitary structure and the notochord of the Vertebrata is not approached by any member of the other groups of the animal kingdom. At the same time, the Invertebrata do not form an assemblage equivalent in value to the Vertebrata, but contain many such assemblages. On the other hand, when we examine the lowest members of the Invertebrata where they approach the kingdom of plants, we find no such sharp line; in fact, it seems impossible to erect a definite boundary. The points which separate undoubted plants and animals, are sufficiently numerous. The plant has a cellulose investment to its cell, does not exhibit locomotive * or con

*Professor Huxley must have spoken these words unadvisedly, as the motile zoospores of undoubted plants abundantly show.-ED.