Hofmann has achieved another triumph in a department of chemistry which he has made peculiarly his own. In 1857 he showed that alcohol bases, analogous to those derived from ammonia, could be obtained by replacement from phosphuretted hydrogen; but he failed in his attempts to prepare the two lower derivatives. These missing links he has now supplied, and has thus established a complete parallelism between the derivatives of ammonia and of phosphuretted hydrogen. The same able chemist has lately described the aromatic cyanates, of which one only, the phenylic cyanate (CO, C, H,, N), was previously known, having been discovered about twenty years ago by Hofmann himself. He now prepares this compound by the action of phosphoric anhydride on phenylurethane, and by a similar method he has obtained the tolylic, xylylic, and naphthylic cyanates.

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Stenhouse had observed many years ago that when aniline is added to furfurol the mixture becomes rose-red, and communicates a fugitive red stain to the skin, and also to linen and silk. He has lately resumed the investigation of this subject, and has obtained two new bases, furfuraniline and furfurtoluidine, which, like rosaniline, form beautifully coloured salts, although the bases themselves are nearly colourless, or of a pale brown colour. The furfuraniline hydrochlorate (C1, H19 O, N, CI) is prepared by adding furfurol to an alcoholic solution of aniline hydrochlorate containing an excess of aniline. We have also from Stenhouse a new contribution to the history of orcin, in continuation of his former masterly researches on that body. He has prepared the trinitroorcin (C, H, (NO2), O,), a powerful acid, having many points of resemblance to picric acid. In connexion with another research of Stenhouse made many years ago, it is interesting to find his formula for euxanthon, which was also that of Erdmann, confirmed by the recent experiments of Baeyer.

The interesting work of Dewar on the oxidation of picoline must not be passed over without notice. By the action of the permanganate of potassium on that body, he has obtained a new acid which bears the same relation to pyridine that phthalic acid does to benzol. Thorpe and Young have published a preliminary notice of some results of great promise which they have obtained by exposing paraffin to a high temperature in closed vessels. By this treatment it is almost completely resolved into liquid hydrocarbons, whose boiling-points range from 18° C. to 300° C. Those boiling under 100 have been examined, and consist chiefly of olefines. In connexion with this subject, it may be interesting to recall the experiments of Pelouze and Cahours on the Pennsylvanian oils, which proved to be a mixture of carbohydrogens belonging to the marsh-gas series.

An elaborate exposition of Berthelot's method of transforming an organic compound into a hydrocarbon containing a maximum of hydrogen has appeared in a connected form. The organic body is heated in a sealed tube, with a large excess of a strong solution of hydriodic acid, to the temperature of 275°. The pressure in these experiments Berthelot estimates at 100 atmospheres, but apparently without having made any direct measurements. He has thus prepared ethyl hydride (CH) from alcohol, aldehyde, &c., hexyl hydride (C, H,4) from benzol. Berthelot has submitted both wood-charcoal and coal to the reducing action of hydriodic acid, and among other interesting results he claims to have obtained in this way oil of petroleum.

By the action of chloride of zinc upon codeia, Matthiessen and Burnside have obtained apocodeia, which stands to codeia in the same relation as apomorphia to morphia, an atom of water being abstracted in its formation. Apocodeia is more stable than apomorphia, but the action of reagents upon the two bases is very similar. As regards their physiological action, the hydrochlorate of apocodeia is a mild emetic, while that of apomorphia is an emetic of great activity. Other bases have been obtained by Wright by the action of hydrobromic acid on codeia. In two of these bases, bromotetracodeia and chlorotetracodeia, four molecules of the codeia are welded together, so that they contain no less than seventy-two atoms of carbon. They have a bitter taste, but little physiological action. The authors of these valuable researches were indebted to Messrs. Macfarlane for the precious material upon which they operated.

We are indebted to Crum Brown and Fraser for an important work on a subject of great practical as well as theoretical interest,-the relation between chemical

constitution and physiological action. It has long been known that the ferrocyanide of potassium does not act as a poison on the animal system, and Bunsen has shown that the kakodylic acid, an arsenical compound, is also inert. Crum Brown and Fraser find that the methyl compounds of strychnia, brucia, and thebaia are much less active poisons than the alkaloids themselves, and the character of their physiological action is also different. The hypnotic action of the sulphate of methyl-morphium is less than that of morphia; but a reverse result occurs in the case of atropia, whose methyl and ethyl derivatives are much more poisonous than the salts of atropia itself.

Before proceeding to the subject of fermentation, I may refer to Apjohn's chemico-optical method of separating cane-sugar, inverted sugar, and grape-sugar from one another when present in the same solution, by observing the rotative power of the syrup before and after inversion, and combining the indications of the saccharometer with the results of an analysis of the same syrup after inversion. Heisch's test for sewage in ordinary water is also deserving of notice. It consists in adding a few grains of pure sugar to the water, and exposing it freely to light for some hours, when the liquid will become turbid from the formation of a wellmarked fungus if sewage to the smallest amount be present. Frankland has made the important observation that the development of this fungus depends upon the presence of the phosphate, and that if this condition be secured, the fungus will appear even in the purest water.

The nature of fermentation, and in particular of the alcoholic fermentation, has been lately discussed by Liebig with consummate ability, and his elaborate memoir will well repay a careful perusal. Dr. Williamson has also given a most instructive account of the subject, particularly with reference to the researches of Pasteur, in his recent Cantor lectures. A brief statement of the present position of the question will therefore not be out of place here. It is now thirty-four years since Cagniard de La Tour and Schwann proved by independent observations that yeastglobules are organized bodies capable of reproduction by gemmation; and also inferred as highly probable that the phenomena of fermentation are induced by the development or living action of these globules. These views, after having fallen into abeyance, were revived and extended a few years ago by Pasteur, whose able researches are familiar to every chemist. Pasteur, while acknowledging that he was ignorant of the nature of the chemical act, or of the intimate cause of the splitting up of sugar in the alcoholic fermentation, maintained that all fermentations properly so called are correlative with physiological phenomena. According to Liebig, the development and multiplication of the yeast-plant or fungus is dependent upon the presence and absorption of nutriment, which becomes part of the living organism, while in the process of fermentation an external action takes place upon the substance, and causes it to split up into products which cannot be made use of by the plant. The vital process and the chemical action, he asserts, are two phenomena which in the explanation must be kept separate from one another. The action of a ferment upon a fermentable body he compares to the action of heat upon organic molecules, both of which cause a movement in the internal arrangement of the atoms. The phenomena of fermentation Liebig refers now, as formerly, to a chemico-physical cause,-the action, namely, which a substance in a state of molecular movement exercises upon another of highly complex constitution, whose elements are held together by a feeble affinity, and are to some extent in a state of tension or strain. Baeyer, who considers that in the alcoholic and lactic fermentations one part of the compound is reduced and another oxidized, adopts the view of Liebig, that the molecules of sugar which undergo fermentation do not serve for the nourishment of the yeast-plant, but receive an impulse from it. All are, however, agreed that fermentation is arrested by the death of the plant; and even a tendency to the acetous fermentation in wine may be checked, as Pasteur has shown, by heating the wine to a temperature a little below the boilingpoint in the vessel in which it is afterwards to be kept.

I regret that the limits of an address like the present forbid me to pursue further this analysis of chemical work. Had they admitted of abridgment, I should gladly have described the elaborate experiments of Gore on hydrofluoric acid and the fluoride of silver. The important researches of Abel on explosive 1871.

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compounds will be explained by himself in a lecture with which he has kindly undertaken to favour the Association. Mr. Tomlinson will also communicate to the Section some observations on catharism and nuclei, a difficult subject, to which he has of late devoted much attention; and I am also informed that we shall have important papers on recent improvements in chemical manufacture.

No one can be more painfully alive than myself to the serious omissions in the historical review I have now read, more particularly in organic chemistry, where it was wholly impossible to grapple with the large number of valuable works which even a few months produce. I cannot, however, refrain from bearing an humble tribute to the great ability and indomitable perseverance which characterize the labourers in the great field of organic chemistry. It would scarcely be possible to conceive any work more intelligently undertaken or more conscientiously performed than theirs, yet much of it, from its abstruse character, receiving little sympathy or encouragement except from the band of devoted men who have made this subject the chief pursuit of their lives. They will, however, find their reward in the consciousness that they have not lived in vain, but have been engaged, and successfully engaged, in the noble enterprise of extending for the benefit of the human family the boundaries of scientific knowledge. Nor is there any real ground for discouragement. Faraday, Graham, Magnus, and Herschel, who have left their impress on this age, were all distinguished chemical as well as physical discoverers; and the relations of the sciences are becoming every day so intimate that the most special research leads often to results of wide and general interest. No one felt this truth more clearly or illustrated it better in his writings than our lamented and distinguished friend Dr. Miller, whose presence used to cheer our meetings, and whose loss we all most sincerely deplore.

Facts developed by the Working of Hæmatite Ores in the Ulverstone and Whitehaven Districts from 1844-71. By THOMAS AINSWORTH.

On the Dichroism of the Vapour of Iodine. By Dr. ANDREWS, F.R.S. The fine purple colour of the vapour of iodine arises from its transmitting freely the red and blue rays of the spectrum, while it absorbs nearly the whole of the green rays. The transmitted light passes freely through a red copper or a blue cobalt glass. But if the iodine vapour be sufficiently dense, the whole of the red rays are absorbed, and the transmitted rays are of a pure blue colour; they are now freely transmitted, as before, by the cobalt glass, but will not pass through the red glass. A solution of iodine in sulphide of carbon exhibits a similar dichroism, and according to its density appears either purple or blue when white light is transmitted through it. The alcoholic solution, on the contrary, is of a red colour, and does not exhibit any dichroism.

On the Action of Heat on Bromine. By Dr. ANDREWS, F.R.S.

A

If a fine tube is filled one half with liquid bromine and one half with the vapour of bromine, and after being hermetically sealed is gradually heated till the temperature is above the critical point, the whole of the bromine becomes quite opaque, and the tube has the aspect of being filled with a dark red and opaque resin. measure of the change of power of transmitting light in this case may be obtained by varying the proportion of liquid and vapour in the tube. Even liquid bromine transmits much less light when heated strongly in an hermetically sealed tube than in its ordinary state.

Some Remarks upon the Proximate Analysis of Saccharine Matters.
By Professor APJOHN, F.R.S.

On the Examination of Water for Sanitary purposes. By GUSTAV BISCHOF. The principle of the method consists in evaporating 1 cub. centim. of the water to be examined in a cell formed by cementing a glass ring on a slip of plate glass, such as used for mounting microscopic objects. By means of certain appliances dust is effectually excluded during the evaporation. The temperature at which the samples are evaporated (40° to 45° C.) is regulated by a Kemp-Bunsen gasregulator improved for the purpose by the author.

If pure water, such as we find naturally, be evaporated, one observes under the microscope in the residue essentially colourless, or nearly colourless, dendritic, branching, tree-like, and well-defined hexagonal and rhombohedral crystals of calcium carbonate. In the case of natural impure water, or if pure water be contaminated by adding minute quantities of either sewage or urine, the above crystals are no longer perceptible, and, according to the degree of impurity, their place is taken by more or less imperfectly defined yellowish-brown or red hexagonal or rhombohedral crystals of calcium carbonate, or by hexagonal twin-crystals, or triangles with rounded angles, or, finally, drops of fat and the so-called dumb-bells (which latter are either fatty matter or germs of fungi) make their appearance.

If the presence of germs of fungi be doubtful, they are determined by cultivating the residue in a damp chamber for some forty-eight hours before it is quite evaporated to dryness. Several well-definable species of fungi have thus been produced.

The results of the examination of a number of samples, illustrated by several lithographed plates, proved that one-thousandth part of sewage or urine added to pure water so completely altered the appearance of the residue as to lead to the conclusion that still more minute quantities of the above impurities can also be detected in water by this method.

On the other hand, the residue of sewage which had been filtered through spongy iron (the process to which the author called attention at the last Meeting of the Association) exhibited throughout the characteristics of the purest water. Professor Voelcker arrived also, by chemical analysis, at the result that the sewage filtered through spongy iron was "remarkably free from organic matter, containing less organic matter than many excellent drinking-waters," thus proving that analysis and the microscopic examination come to the same conclusion.

In concluding, some residues of natural waters exhibited in the plates referred to above were explained as to their characteristics.

On the Crystallization of Metals by Electricity. By PHILIP BRAHAM.

The author of this paper gave an account of experiments with electricity under the microscope. Solutions of neutral metallic salts were placed between terminals of the base, and crystals of several metals were formed. The author hopes by the same means to obtain crystals of all.

The apparatus for regulating the quantity and intensity of the electricity was exhibited and explained.

The author then drew attention to the shape of the crystals, and suggested that, being built up of molecules, they might be typical of their elementary forms.

On the Rate of Action of Caustic Soda on a watery Solution of Chloracetic Acid at 100° C. By J. Y. BUсHanan.

Two sets of experiments were made. In the one, the composition of the solution was expressed by the formula C, H, CIO,+NaHO+1591, O, in the other by C, H, CIO, +2NaHO+159H, O; 10 cub. centims. of the different solutions were used for every experiment. The results are given in the following Tables:

The sulphur found in coal or coke often exists in two states, partly as sulphuric acid combined with lime, and partly as sulphur combined with iron. The part combined with lime, however, does not injure the quality of the iron produced when used in the manufacture of that article, as it remains in combination with the calcium, whilst the portion existing as sulphuret of iron greatly deteriorates its commercial value. To determine the quantity of sulphur in the former state, the author proposes to boil the pulverized coal or coke with a solution of carbonate of soda, which decomposes the sulphate of lime or sulphuret of calcium, and the sulphur is estimated in the solution. To show the importance of this fact in estimating the suitability of coal or coke for use in the manufacture of iron, the author gave the following percentage of sulphur as the mean of the determination in six samples of coal :

These coals by the old process would be condemned as unsuitable for use in the blast-furnace, while they are really good coals for the purpose.

In the residue from the above operation is found the sulphur combined with the iron. After attacking with oxidizing aqua regia, the author treats with carbonate of soda and heats to near the fusing-point. By this means there can be no formation of an insoluble subsulphate of iron, and the prevention of precipitation by a salt of baryta, which occurs in a liquor containing free nitric acid, is avoided.

On the Existence of Sulphur Dichloride. By JOHN DALZELL and T. E. THORPE. The authors have confirmed the experiments of Hübner and Gueront, who con