Acclimatization of Palm-Trees.-In addition to the date-palm and the Chamaerops, which have long been naturalized on the European shores of the Mediterranean, M. Naudin has succeeded very well with several other kinds at Collioure, in the Pyrenees, notwithstanding the exceptionally unfavourable character of the winter of 1869-70. The severe cold of the last week of December, when the thermometer descended to 4°, and in some localities even to -6° C., was fatal to only one species. The extraordinarily heavy fall of snow which took place in January, lasting for fortyfour hours without intermission, was expected to destroy the young trees altogether. After, however, they had been entirely covered up with snow for nine or ten days, so that the boughs were completely flattened, when the thaw came they almost immediately recovered their former position, even the green colour of the leaves not being injured. The same fall of snow caused a fearful amount of destruction among the olives and cork-oaks.

Mimetic Plants.-At a recent soirée of the Linnean Society a very interesting set of foliage-plants was exhibited by Mr. W. Wilson Saunders, arranged in pairs, the plants of each pair bearing such a striking resemblance to one another in the general character of the foliage, and even in the venation of the leaves, as to be with difficulty distinguishable from one another, and yet belonging to entirely distinct natural orders, not in any way related to one another. Mr. Saunders states that none of the plants were grown for the purpose, but were selected on the spur of the moment from his collections; and he has little doubt that if attention were drawn to the subject, such a collection might be indefinitely increased.

Parasitic Fungi.-In several recent numbers of the 'Zeitschrift für Parasitenkunde,' edited by Dr. E. Hallier, instances are recorded of diseases of the ear resulting in deafness being caused by minute parasitic fungi. The most certain cure appears to be the external application of spirits of wine.

Recent and Fossil Copal.-At the meeting of the Linnean Society, held May 5th, Dr. J. D. Hooker read a communication from Dr. Kirk, Her Majesty's Vice-Consul at Zanzibar, on the distinction between the recent and fossil states of the resin known in commerce as Copal. One characteristic by which fossil copal is known from the recent resin is the so-called "goose-skin." Dr. Kirk has ascertained that the fossil copal shows no trace of this goose-skin when first dug out of the earth, but that it makes its appearance only after cleaning and brushing the outer surface. Both descriptions often contain imprisoned leaves, flowers, and insects in a beautiful state of preservation; but the fossil variety is clearer and more transparent. Captain Grant states that the true copal gum-tree is a climber reaching to a great height among the forest trees, finally becoming completely detached from its original root, when the copal exudes from

the extremities of these detached roots. Large pieces of the resin fetch a very high price even in that country.

New Species of Jalap.-Mr. Daniel Hanbury contributes to the Journal of the Linnean Society' a description of a hitherto undescribed Convolvulaceous plant, which he names Ipomæa simulans, being the plant the root of which furnishes the article known in commerce as Tampico Jalap. It is obtained from Mexico, and has been extensively brought into the market; and though it is less rich in resin and less purgative than true jalap, yet, on account of its lower price, it has found a ready sale, chiefly in the Continental trade.

5. CHEMISTRY.

IT has long been a disputed question whether a small quantity of phosphorus improves or injures the mechanical properties of steel. M. L. Gruner has carefully examined this subject, and has arrived at the result that phosphorus present in steel in a quantity of from 0.002 to 0.003 causes the metal to be rigid; it tends even to increase the elasticity and the resistance to breaking, but does not modify the hardness. Such steel, however, is wanting in real strength and toughness; it is brittle (aigre), that is to say, does not withstand shocks. The general result is, therefore, that even very small quantities of phosphorus present in steel do not only not improve, but certainly deteriorate, its good qualities. Dr. Salet, the chief assistant to Professor Wurtz, has arranged an ingeniously constructed apparatus to detect the smallest possible quantity of phosphorus in iron and steel, by means of the spectrum produced by the combustion of the hydrogen obtained by the action of chlorhydric acid on the metal.

Since the internal use of amylic alcohol, even in small quantities, is very deleterious, the means of rapidly testing for its presence in spirits and alcohol (either for pharmaceutical or scientific use) is of importance. The suspected alcohol is poured into a burette, mixed with its own bulk of rectified and pure ether, and also its own bulk of water, and the mixture gently shaken; the ether, on becoming separated from the rest of the fluid, floats to the top, containing in solution the whole of the amylic alcohol which might have been contained in the alcohol or spirits under examination. The ether is removed by a pipette, and on leaving it to spontaneous evaporation, will leave behind the amylic alcohol, readily detected by its offensive odour.

The absence of oxygenated water from snow which fell at Rouen has been shown by M. A. Hozeau. He has tried some very careful experiments to detect the presence of peroxide of hydrogen in water

obtained from snow, care being taken to prevent the loss or decomposition of the peroxide alluded to. The author's opinion is that, since the experiments made at Kasan undoubtedly proved the presence of the peroxide of hydrogen in snow-water, there may exist an essential difference, caused by the locality where it falls. Kasan is situated almost in the centre of the Russian empire, far away from any seas or oceans.

On the other hand, Professor H. Struve has ascertained the presence of peroxide of hydrogen in air. His chief results are, (1) peroxide of hydrogen is formed in air simultaneously with ozone and nitrate of ammonia, and is condensed in the rain-water; (2) peroxide of hydrogen, ozone, and nitrate of ammonia, are intimately connected together; (3) the change which the so-called ozonepaper undergoes when exposed to air is due to the joint action of ozone and peroxide of hydrogen; (4) peroxide of hydrogen does not decompose solution of iodide of potassium with separation of free iodine; (5) free carbonic acid decomposes the solution of iodide of potassium, causing the formation of carbonate of potassa and free hydriodic acid; (6) when the peroxide of hydrogen is present along with carbonic acid (acting as just alluded to), iodine is separated; (7) the best and most effective reagent for the detection of small traces of peroxide of hydrogen is oxide of lead, since puce-coloured peroxide is formed.

According to J. Jouglet, nitro-glycerine, dynamite, iodide of nitrogen, chloride of nitrogen, and some other similar compounds, explode the very moment they are brought into contact with ozone; so that, for instance, a drop of nitro-glycerine, introduced into a vessel containing ozone, causes an instantaneous explosion. Picrate of potassa gunpowder, and ordinary gunpowder, are slowly decomposed by ozone, a decomposition which, as regards the last-named substance, takes several weeks before it is perceptible.

Under the name of Albolith, Dr. Riemann prepares a cement chiefly consisting of magnesia. For this purpose, the magnesite of Frankenstein (Silesia) is ignited in retorts similar to those used for gas-manufacture; and after the mineral (a native carbonate of magnesia) has been ignited, it is mixed with silica and some other substances. This mixture has the property of yielding, with moderately concentrated solutions of chlorides (for instance, chloride of magnesium), an extremely plastic, but, on drying, a very hard material, excellently adapted for use as cement for stucco and ornamental work, and instead of gypsum.

In a research on Isinglass, J. L. Souberain states that the different varieties of this article, as met with in the trade, may be recognized as follows:-Russian isinglass dissolves rapidly and instantaneously in hot water, leaving hardly ever more than at most 2 per cent. insoluble residue; Bengal isinglass dissolves readily,

but leaves from 7 to 13 per cent. of residue. The taste of Russian isinglass is pleasant and sweet; it yields a very firm gelatine, which is perfectly transparent. The Bengal, or Indian kind, often has a fishy taste, and the gelatine it yields is not clear. The Brazilian isinglass yields an opaque, milky-looking gelatine, and its taste is acrid. China isinglass is a rare article in the European markets.

An important reaction in synthetical chemistry has been published by Dr. E. Royer, who has effected the formation of formic acid from carbonic acid. The author states that, while submitting to the action of a current of electricity an aqueous solution of carbonic acid, the latter was simply converted into formic acid by the addition of hydrogen.

Owing to the fears of a quinine famine expressed some years ago, great efforts were made to introduce the cultivation of cinchona trees in numerous new localities. We have recently heard of the first importation of cinchona bark from Java, a quantity of some 930 lbs. of this bark having been exported from Java to the Netherlands. According to analysis made by Dr. B. Moens in Java, this bark contains from 2-4 to 7.5 per cent. of alkaloids, of which quantity 0.59 to 3.67 is quinine. The loss of weight occasioned by the drying of the bark has been found to amount to 66 per cent. There is every prospect that within some six or seven years hence Java will largely export this drug; and the cultivation of the cinchona trees is also to be extended to Sumatra, Celebes, and the Moluccas.

Dr. Loew has made known a fact which renders still more probable the Hydrogenium theory of the late Professor Graham. The researches of Graham went to show that hydrogen could be alloyed with palladium, and that it was also contained in meteoric iron. He condensed the hydrogen in the palladium, and came nearer proving its metallic character than any other person had done. Dr. Loew has succeeded in combining hydrogen with mercury. He takes an amalgam composed of not more than 3 or 4 per cent. of zinc, and shakes it with a solution of bichloride of platinum; the liquid becomes black, and a dark powder settles to the bottom. The contents of the flask are then thrown into water and hydrochloric acid added to dissolve the excess of zinc. The amalgam of hydrogen and mercury at once forms in a brilliant voluminous mass, resembling in every way the well-known ammonium amalgam. It is soft and spongy, and rapidly decomposes, but without any smell of ammonia. The hydrogen escapes, and soon nothing but pure mercury is left in the dish. The experiment appears to show that an amalgam of hydrogen and mercury can be formed, and that hydrogen is really a metal.

Now that the analysis of air-physical and chemical-is attracting so much attention, it may be of some interest to know what

substances the New York Metropolitan Board of Health found in the air of the opera-houses. Over one hundred specimens of the particles floating in the air, and falling as dust, were collected on plates of glass, and examined under the microscope. The proportions of the different ingredients varied, but the same substances were found in all the specimens. The composition of the matter subjected to the microscope was as follows:-The dust of the streets in its finer or coarser particles, according to the height at which it had been collected, with a large proportion of organic elements; particles of sand, quartz, and feldspar; of carbon, from coal-dust and lamp-black; fibres of wool and cotton of various tints; epidermic scales; granules of starch of wheat; the tissues of plants, mainly the epidermic tissue, recognized by the stomata or breathing pores; vegetable ducts and fibres, with spiral markings; vegetable hairs or down, either single or in tufts of four or eight, and of great variety, and three distinct kinds of pollens. Fungi were abundant, from mere micrococcus granules to filaments of mould. When water was added to a portion of dust from whatever source, and exposed in a test-tube to sunlight or heat for a few hours, vibriones and bacteria made their appearance, and the fungous elements sprouted and multiplied, showing that they maintained their vitality, and proving that the germs of fermentation and putrefaction are very widely diffused. In connection with this subject, it is right to mention here that Mr. Samuelson performed a similar series of experiments six years ago, on dust from all parts of the world.*

All lecturers who have tried to float and then ignite an explosive balloon will be glad to know the following easy means of effecting this difficult but striking experiment devised by Mr. Patterson. At first the author tried the india-rubber balloons of the toy-shops. From various causes they had failed; but the chief difficulty was doubtless the tension which made it difficult to secure the gases. Recently the author's attention has been directed to the collodion balloons, obtainable from the philosophical instrument makers, believing that they would suit well, both on account of their lightness, and on account of the fact that they would wholly disappear on ignition. After a number of trials he has found them to succeed admirably. The method adopted is as follows:

A fuse of filter-paper, about 1 inch long and inch broad, is gummed to the side of the balloon near the mouth, and allowed to dry. The latter is then filled with a mixture of 2 volumes of hydrogen gas and 1 volume of oxygen, the mixture being prepared in a separate vessel. The mouth of the balloon is at once tied with a piece of thread to increase the force of the explosion. When the balloon is ready to ascend, a drop of the so-called "Greek fire * See 'Quarterly Journal of Science,' July, 1864.