green and blue together, and it is easy to select tints of each colour which are very disagreeable in such a position, but a walk through a flower garden shows how often nature makes such combinations pleasing, and gives us illustrations how to effect it with various blues, from pale sky-blues to violet. Some artists have studied these effects, and succeeded admirably in introducing them into their works.

A musical theory of colour will not go far in elucidating painting, but, to the extent to which the analogy it traces is applicable, it deserves

attention.

By

LESSONS IN ELEMENTARY CHEMISTRY, INORGANIC AND ORGANIC. HENRY G. ROSCOE, B.A., F.R.S., Professor of Chemistry in Queen's College, Manchester. New Edition. (Macmillan.)—This is one of the best books of its class, and forms an excellent manual of modern chemistry. The theoretical portions of the teaching are judiciously brought in at convenient places, after the facts on which they depend have been explained. The work ranges from the non-metallic to the metallic elements, with a chapter on spectrum analysis, and several on organic chemistry. There is a little slip at page 59, where it is asserted, that "had air been a chemical compound, it would be impossible to decompose it by simply shaking it up with water." Professor Roscoe certainly does not mean that no chemical compound can be decomposed by contact with water, and yet this is what he implies by the words cited. In his account of fermentations, while he justly refers them to the action of organized beings, he affirms-we suppose on Pasteur's authority-that the organisms producing butyric fermentation are animal, of which there is not the slightest proof. Many French writers speak of bacteriums, vibrions, etc. as animal, without any justification for the term.

NOTES AND MEMORANDA.

POCKET SPECTROSCOPE.-The most perfect and beautiful instrument of this kind which we have seen has recently been constructed by Mr. Browning, with the aid of glass of unusual density. It is only 3 inches long and ths of an inch wide. The opening and closing of the slit is effected in a very ingenious way, by rotating a brass terminal rim. A surprising number of lines for so small an apparatus can be seen on directing it to a bright portion of the sky, and the definition is sharp and clear. When used against a light sky, the slit only requires to be open to the extent of 1-300" or less, and a very curious effect is produced in the dirty atmosphere usually found, even on clear days, in and near the metropolis. If the adjustment for focus is made by pulling the adjusting slide out, enough floating atmospheric particles are sucked in to stop all vision; but by adjusting in the opposite direction, and thrusting in the slide, he dirt particles are blown out, and plenty of light appears. This instrument can easily be adjusted to the microscope, and possesses power enough for a considerable range of

observation.

TADPOLES OF Newts and their EGGS.—M. J. Julien states, in "Comptes Rendus," that he has discovered perfect eggs in tadpoles of the female Lissotriton punctatus, and that he has found such tadpoles with the generative organs in the adult stage, while the rest of the creature was in the larval condition.

INSANITY IN FRANCE.-Dr. Lumier states, that on the 1st of January, 1869, France had one insane person for every 412 inhabitants. Paralytic idiotcy (folie paralytique), he states to be increasing, not only in the great towns, but in less important centres. He says it is an error to suppose that insanity attacks women more than men. “If,” he adds, "it is correct to say that at any given moment there are in the asylums rather more women than men, it is not less certain that more men than women enter these institutions every year, and that in the proportion of 54 to 46.

THE TRANSIT OF Venus in 1874.-At the last meeting of the Royal Astronomical Society, the subject of Mr. Proctor's statements respecting this transit was dealt with. While the correctness of his views was admitted, some doubt was expressed as to their importance. Mr. Stone pointed out that the stations mentioned by Mr. Airy as the best are those which Mr. Proctor also approves of. Mr. Proctor maintained that the relative values of those stations were so affected, that in the final selection others than those chosen by Mr. Airy would probably be preferred. He adduced the superiority of Crozet Island over Kerguelen Land as one of several instances in point. Mr. Stone also questioned whether the superiority of Halley's method were marked enough to be important; in answer to which Mr. Proctor pointed out, that that superiority, however slight, differed importantly from the total failure hitherto ascribed to the method. He stated, also, that the proposed expedition to South Victoria Land, in 1882, would be useless; and that the proof of this circumstance was of itself sufficient to justify his paper.

PERIODIC WEATHER CHANGES.-M. St. Claire Deville, in presenting to the French Academy the Annual Report of the French Meteorological Society, expressed a belief, founded upon a study of the facts, that in each year there are, at least, three cycles : one of 90 days, or quarduple; a second of 30 days, or dodécuple; a third of ten days, or tridodécuple, which manifest themselves by periodical returns of temperature. He says, supposing the year reduced to 360 angular days, each corresponding to a movement of the earth of one degree on the ecliptic, it would be important to ascertain whether there is a cycle of years periodically exhibiting the same influences. The periodic oscillations of temperature he notes in each year are connected with variations of pressure, moisture, photometric, electric, and other conditions, which affect the health of the people. He thinks the changes may be explained by the conditions of the different portions of interplanetary space traversed by the sun's rays.

RAIN OF INSECTS AT ARACHES AND TURIN.-M. Rey de Morande (as stated in "Cosmos") says, that on the night of the 29-30th January, about 4.30 a.m, a violent blast of wind suddenly stopped, and snow fell at Arâches, in Haute Savoie, till daybreak, and in the morning a quantity of live larvæ was found in it. They could not have been hatched in that locality, as the temperature of the preceding days had been too low. They belonged for the most part to Trogossita mauritanica, common in old wood in the forests of the south of France. Some caterpillars, supposed to belong to Stibia stagnicola, were likewise noticed. This caterpillar belongs to the south of France, and attains its full size in the month of February. M. Tissot, who observed the preceding phenomenon, says a storm brought thousands of insects to Turin in 1854, some of them only found in the island of Sardinia.

POISON GLANDS OF CALLOPHIS.-M. Bernhard-Meyer describes to the French Academy his dissections of several species of the snakes called Callophis, in which he finds the poison glands, situate in the belly, and the heart nearer the tail. The excretory canals from these glands unite in a canal which reaches the fangs.