of a branch of a healthy plant is even sufficient to produce the disease. Variegation may be produced by various causes, debility in the seed, dampness of the ground, want of light, &c. It can be propagated by layers, buds, or grafts, but not, under ordinary circumstances, by seeds. Variegation is partial decoloration or want of strength to produce the green grains of chlorophyll; if the decoloration is general, it causes death. None of the higher plants, except a few which are parasitic, can exist if entirely deprived of chlorophyll; though a perfectly blanched branch may occasionally lead a parasitic life on the remainder of the plant.

Cultivation of Cinchona.-Many climates are now found to be adapted to the profitable growth of the Cinchona, or Peruvian bark. In addition to its introduction into St. Helena, reported some time since, it is now grown on a small scale in the Azores. In our own governments of Madras and Bengal its cultivation is rapidly extending. From a report recently published by Mr. C. B. Clarke, Assistant-Superintendent of the Botanic Garden at Calcutta, it appears that the increase in the number of plants at the Darjeeling plantations during the year ending March 31st, 1869, was 673,654, making in all over three million plants, belonging to the three species Cinchona officinalis, succirubra, and micrantha, the area covered on the 1st of April, 1869, being 965 acres. There is also a smaller Government plantation at Nunklow, in the Khasia Hills. The tallest plants grown at Darjeeling are 19 feet high. Mr. Broughton, chemist to the Cinchona plantations in the Madras Presidency, believes that all the sub-varieties are permanent, and have been produced by artificial hybridization; but that hybridization seldom takes place in nature.

The Chair of Botany at the College of Science, Dublin. This appointment, vacant by the resignation of Professor Wyville Thomson, has been conferred on Mr. W. T. Dyer, author of A Flora of Middlesex.' A vacancy is thus occasioned in the Professorship of Natural History in the Royal Agricultural College at Cirencester.

5. CHEMISTRY.

A VERY unexpected fact has been published by Professor Wanklyn. It has usually been considered that the affinity of chlorine for the alkali metals was very energetic, and when it is remembered that antimony and arsenic burst into flame when introduced into this gas, it was reasonable to suppose that the reaction between chlorine and sodium would be even more violent. Mr. Wanklyn, however, has shown that when chlorine gas is passed over metallic sodiumeven when the metal is fused, and, whilst in a state of fusion, shaken

in contact with the gas, so as to expose the fresh metallic surfacethere is no action. A glass vessel containing a piece of sodium was weighed, and after the transmission of chlorine, under the circumstances above named, it was re-weighed, and found to be practically the same.

Mr. H. C. Sorby has published a detailed account of some remarkable spectra of compounds of zirconia and the oxides of uranium. The phenomena which he has observed are very complicated, and reflect the highest honour on his philosophical acumen. Some of the peculiarities in the spectra of compounds of the oxide of uranium with zirconia, led Mr. Sorby and others, some time back, to conclude that they were due to a new elementary substance.

A rapid method for the quantitative estimation of sulphur in cast-iron and steel is a great desideratum in metallurgical laboratories. Mr. Eggertz has described a process, based upon the shade of coloration which small quantities of sulphuretted hydrogen produce upon pure silver, or certain alloys thereof. In a glass-stoppered bottle, a mixture is poured of water and sulphuric acid, to which is added the metal, reduced to the finest possible powder. There is then suspended, by means of a very fine platinum wire, in the bottle, without touching the fluid, a clean piece of metallic silver, the platinum wire being held squeezed between the stopper and the neck of the bottle. The metal dissolves, in a moderately warm room, within a quarter of an hour, so that the silver can be taken out and examined after that time. The author has, by means of a series of experiments, been enabled to construct a scale of numbers representing, according to certain shades of coloration, the quantities of sulphur found.

Naphthaline is a waste product occurring in large quantities in gas works. The problem is how to utilize it. Dr. Ott has examined its properties with this object. Pure naphthaline is similar in appearance to alabaster, cracks easily in the warm hands, and becomes negatively electric on being rubbed with silk. It melts at 174° F., and boils at 452° F. Molten naphthaline absorbs a large quantity of air, which is given off again on cooling; according to M. Vohl, this gas is pure oxygen. Molten naphthaline dissolves indigo with great facility, forming a dark-blue violet liquid, from which the indigo separates on cooling, forming fine shining needles like copper. The amorphous sulphides of arsenic, tin, and antimony are also readily dissolved, and likewise phosphorus, sulphur, iodine, the iodide and chloride of mercury, arsenious, succinic, benzoic, and oxalic acids. Professor Asa Gray has thoroughly tested and obtained satisfactory results, proving that naphthaline may be advantageously used in museums, herbariums, &c., instead of camphor, as a very effective protection against moths and other insects.

It appears that in the utilization of the cane sugar existing in Madder-root, there is a fair field of profitable experimental research still left open and untouched. Madder-root, and especially the Zealand madder, is rich in cane sugar, containing between 14 and 16 per cent. The extraction of this sugar, without interfering with the tinctorial value of madder, and by means different from those whereby that sugar is now utilized-viz. fermentation and making of alcohol-is a problem still to be solved. Some 10,000,000 kilos. of madder are, at the very lowest estimate, consumed annually, and the bulk of the sugar therein contained is utterly lost.

We have received, from Mr. H. N. Draper, a pamphlet, from which we learn that the use of methylated ether as an intoxicant, instead of alcohol, is very general in the counties of Londonderry, Antrim, and Tyrone. The quantity taken at one time is from two to four drachms, and the dose is repeated twice, thrice, or even four and six times daily. Mr. Draper treats the subject in its relation to the inland revenue, and also to insurance companies, the former suffering by the practice to the extent of 56667. per annum, while the risks of the latter are increased by such an inflammable liquid being stored and handled by people ignorant of its properties.

As a new disinfectant M. Paquet proposes the use of thymol, the stearopten of the essential oil from Ptychotis ajowan, an umbelliferous plant growing in India. In the undiluted state, this substance is a caustic, and is used in dentistry for the cauterization of hollow teeth; its advantage in this respect being that it has not an unpleasant taste, and, being very aromatic, does not affect the breath as carbolic acid does. Its aqueous solution is a strong antiseptic, and possesses disinfectant properties in a very high degree.

MM. Sepulchre and Ohressir have perfectly succeeded in utilizing the slag of the iron blast furnaces for the manufacture of paving stones, which withstand a crushing weight of more than 400 kilos. per square centim., and have answered for the purpose of paving several streets at Brussels and Paris, and stood heavy traffic, far better than even the celebrated Quenast stones. The streets paved with this material at Brussels have a heavy gradient.

The fatty matter contained in sheep's wool, technically known as snint, is likely to become of considerable commercial importance. It contains some 40 per cent. of potassa; and when ignited this alkali becomes thereby intimately mixed with strongly-nitrogenized animal charcoal. M. Havrez points out the profit to be derived from the use of snint for the manufacture of prussiates and cyanides, and M. Schattenmann, prussiate and cyanide manufacturer at Bouxwillir, near Strasburg, states that results of experiments made with snint by him on large scale, are decidedly favourable to the use of

that substance for the purpose alluded to. It should be observed that the quantity of snint contained in raw wool amounts to onethird of its weight; and that in 1867 there were imported into the United Kingdom 63,000,000 kilos. of raw wool from the Cape and Australia, the quantity of snint contained therein amounting to at least 20,000,000 kilos.

The use of hypophosphoric acid in agriculture for the purpose of destroying noxious insects has been proposed by M. Martin, for the destruction of the Phylloxera vastatrix, which makes great havoc in the vineyards. The makers of phosphorus obtain a quantity of this acid in aqueous solution, which is thrown away as waste; but since the transport of this waste liquid is too costly (it may be very usefully applied where it can be had with ease), the author describes a method of making hypophosphoric acid by the slow combustion of phosphorus. According to his experiments, 2 grammes of this acid dissolved in 10 or 12 litres of water, is a strong poison for all kinds of insects, and not only does not hurt plants, but actually does good by increasing the soluble phosphates in the soil.

The solution of oxide of copper in ammonia acts as an energetic solvent upon cellulose; this property is made use of by A. Jouglet to waterproof paper in the following manner :-A tank is made to contain the solution just alluded to, and the paper is rapidly passed just over and in contact with the surface of the liquid, by means of properly-placed rollers moving with speed. The paper, on leaving, is pressed between two cylinders, and next dried by means of so-called drying cylinders, similar to those in use in paper-mills. The short contact of the felty paper-tissue with the liquid gives rise to just sufficient solution of cellulose to form an impermeable varnish.

A process for the preservation of butchers' meat, invented by M. Georges, is now in use on the large scale at Monte Video. The meat, in pieces weighing from 2 to 50 kilos., is placed in a mixture of water, hydrochloric acid, glycerine, and bisulphite of soda. After having been steeped for some time, the pieces are taken out and dusted over with finely-powdered dry bisulphite of soda, and then packed in air-tight boxes, filled as full as possible. In this state the meat keeps fresh any length of time, and becomes perfectly fit for use-equal to fresh butchers' meat-by steeping for a short time in water to which vinegar has been added, and afterwards exposure to air; the price of the preserved meat, of which it would be easy to supply to London and to Paris daily over 10 tons, is from 50 to 60 centimes per kilo.

Hydrate of chloral, the new anæsthetic and sedative, is daily increasing in importance, and many processes have been given for

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its preparation: the best is probably that of MM. Müller and Paul. Their process consists in passing a current of dry and pure chlorine gas into pure and absolute alcohol, until the contents of the flask are, after about seventy hours, converted into a white and crystalline mass; when this operation is properly conducted, a large quantity of hydrate of chloral is obtained. Hydrate of chloral is readily sublimed, and may be thus obtained as a dry, snow-white, neutral crystalline powder. It does not exhibit any smell at the ordinary temperature of the air; it volatilizes slowly, without absorbing much moisture, unless it be placed in a very damp place; it fuses at 56°, boils at 145°, is completely soluble in a small quantity of water, and also soluble in alcohol, ether, chloroform, sulphide of carbon, benzol, and fatty substances. Its aqueous solution ought to be neutral to test-paper, and should not become turbid by a solution of nitrate of silver.

It is now proposed to make the reflecting surfaces of lookingglasses of platinum instead of tin amalgam or silver. M. Jouglet prepares the platinizing compound in the following manner :-Very thin platinum foil is dissolved in aqua regia, the solution carefully evaporated to dryness, the solid chloride next placed on a triturating marble, and gradually mixed with essential oil of lavender. When incorporated with the chloride, the mixture is placed in a porcelain capsule, and left standing for several days; the fluid is decanted from any sediment, and filtered. As flux for 100 grains of platinum the following ingredients are used:-25 grains of litharge and 25 grains of borate of lead, mixed and triturated together with about 10 grains of essence of lavender; this is next mixed with the platinizing fluid. After a layer of platinum has been formed upon the glass, it is fixed by burning it in by placing the glass in peculiarly-constructed muffles.

From a series of observations made at Monaco, on the shores of the Mediterranean, Dr. Gillebert d'Hercourt concludes that there is always on the sea-shore an atmosphere impregnated with saline particles; this layer of air has, at the above-named place, some 500 metres horizontal and 60 metres vertical extent. This impregnation of salt is due to what the author terms "pulverization" of the sea-water by the breaking up of the surf, and is not directly influenced either by barometric pressure, hygrometric state of the atmosphere, or temperature. This hydro-mineral dust, as it is called by the author, is, unless there happen to exist near the coast physical obstacles in the shape of high mountains, carried far away inland, and is not to be confounded with what is of more coarse nature, and termed "spray," which is only quite local and produced when a gale of wind blows. The author states that, even on calm days in winter, the atmosphere near Monaco is up to a height of 70