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 ef 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 Estimation of Sulphur in Coal and Coke.

By F. CRACE-CALVERT, F.R.S.

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:

Estimated

together.

1.51

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

clude that, contrary to the opinion of Carius, the compound of sulphur and chlorine analogous to water does actually exist as an extremely unstable body, readily parting with a portion of its chlorine on being gently heated.

Deacon's Chlorine Process as applied to the Manufacture of Bleaching-powder on the larger Scale, By HENRY DEACON.

On Sorbit. By Professor DELFFS, of Heidelberg.

Twenty years ago M. Pelouze (Ann. de Chim. et de Phys. 3 ser. xxxv. p. 222) discovered a crystallized substance in the fruits of Sorbus aucuparia which he called Sorbin. Since that time very few chemists have paid attention to this substance, and, as far as I know, nobody in my country has succeeded in preparing it again. The principal of one of our greatest manufactories of chemical preparations, to whom I addressed myself, told me that he never found the least trace of the said substance, although he had worked up large quantities of the abovementioned fruits for preparing malic acid; and to the same result came M. Byschl (Buchner's N. Repert. der Pharm. iii. p. 4), who asserts that there is no ready formed sorbin in the ripe berries of Sorbus aucuparia. In my two first attempts to procure sorbin I also failed; but during last year I succeeded, and at the same time I became aware of the reason of my previous failures. When I first tried to get sorbin, I thought it advisable to combine the preparation of malic acid with the process given by M. Pelouze for getting sorbin, and therefore I separated the former by means of acetate of lead. This is the reason, I think, which has prevented the success of myself as well as of other chemists in the preparation of sorbin.

I will not repeat the method of forming sorbin given in all manuals of chemistry; it is sufficient to say that, when I kept strictly to the prescription of M. Pelouze, I got a large quantity of beautiful crystals, a specimen of which was contained in the tube exhibited. After I had got these, I tried to obtain the malic acid from the residue, but I found that the malic acid had quite disappeared. To this I must add that the alcoholic fermentation which takes place after the juice of the berries of Sorbus aucuparia has been left a few days in a tepid place is more easily perceived by the formation of carbonic acid than by the smell of spirit of wine. I think it, therefore, not improbable that there is a connexion between the disappearance of the malic acid and the small produce of spirit of wine on the one side, and the formation of sorbin on the other. Suppose the malic acid, commonly called bibasic, and therefore apt to form a bimalate of ethyl (=C1 H3 O+ 2C1 Î2 O1+HO), assimilates two equivalents of water to this compound, you will have then the equation

CIIO+2CH2 O1+3H0=C12 H12 012,

the right-hand side of which gives the composition of sorbin.

As pertaining to the preparation of sorbin, I have only to add that the dark sticky ley in which the crystals are formed can very easily be separated by putting both on a brick. After a few days' repose the brick has absorbed nearly all the ley, and the pale yellow-coloured crystals of sorbin, if dissolved in water and left to spontaneous evaporation, become very soon colourless.

The sorbin belongs to the same group as the mannit, quercit, inosit, dulcit, picrit, &c.; and as the last syllable is always characteristic in chemistry, its name, I think, should be changed into sorbit.

Further experiments are required to prove if the supposed genesis of sorbit is true or not; but, in any case, I am convinced that there is no sorbin ready formed in the fruits of Sorbus aucuparia.

On the Detection of Morphine by Iodic Acid. By Prof. DELFFS. Among the poisonous alkaloids which in forensic cases most frequently give occasion for chemical investigations morphine occupies the first place. For its

detection a great many tests have been proposed, most of which, however, have little interest for the forensic chemist, particularly as they depend on phenomena which may also be produced by other substances beside morphine. It is not intended here to justify this assertion by a critical examination of all the tests for morphine which are liable to the reproach mentioned; it will be sufficient to signalize one of them, the iodic acid, as an example. The well-known property of this acid, of being reduced by morphine, is certainly adapted to distinguish the latter from other alkaloids, but is altogether insufficient to establish the nature of morphine, because there are a great many other substances, partly of organic, partly of inorganic origin, which likewise reduce iodic acid. Nevertheless I have found that iodic acid, with the aid of the microscope, presents a sure means of characterizing morphine perfectly, because the reaction between this alkaloid and the above-mentioned test proceeds under such peculiar appearances that morphine cannot be mistaken for any other substance. The process to be adopted for this purpose is the following:

After the morphine (of which the smallest particle is sufficient) is placed on a slip of glass and covered with a glass cover, as much water is added as will fill the space between the slip and the cover and extend a little beyond the margin of the latter. After the glass slip is put under the microscope and this is directed to the morphine, a particle of iodic acid is put into the water at the margin of the covering glass. In a few moments a great number of minute spherical yellow molecules, of constantly equal diameter, are seen to move in a direction from the iodic acid to the sides of the morphine, and soon form in its vicinity numerous colourless needleshaped crystals, mostly united so as to form tufts. For the observation of this microscopic metamorphosis a magnifying-power of 300 linear would be the most suitable; when a more powerful system of lenses is employed, the difference of the focal distances of the morphine and the above-mentioned molecules and crystals readily becomes too great for the distinct observation of the whole simultaneously. Hence it is also advantageous to place under the covering glass the thinnest possible fragment of morphine.

I reserve for another place a more detailed communication on this subject.

Experiments on Chemical Dynamics.

By J. H. GLADSTONE, F.R.S., and ALFRED TRIBE, F.C.S.

The authors had recently communicated a paper to the Royal Society in which they investigated somewhat minutely what takes place when a plate of one metal, such as copper, is immersed in a solution of a salt of another metal, such as nitrate of silver. They had shown that, while the silver was being deposited on the copper, an actual passage of the nitric element towards the more positive metal occurs, causing the formation of a dense solution of nitrate of copper inside the crystalline deposit, and a consequent downward current, and at the same time an upward current of almost pure water from the tips of the crystals. They had shown, also, that with solutions of different strengths the chemical action in a given period (say ten minutes) is not in direct proportion to the strength; but, cæteris paribus, twice the strength gives three times the chemical decomposition. This augmentation had been attributed to an increased conduction of the stronger liquid. In the present paper the authors exhibited these phenomena in a dissected form, and carried the observations still further.

Instead of the silver crystals being allowed to grow from the copper into the nitrate-of-silver solution, two separate plates were taken, one of copper and the other of silver. The copper plate was immersed in nitrate of copper, and the silver plate in nitrate of silver, while the two metals were connected by a wire, and the two liquids were connected by a porous cell. Silver crystals were gradually formed upon the silver plate, while the copper was dissolved; and at the end of some hours it was found that all the silver had been removed from solution, and that the loss of the copper plate was almost exactly what might be calculated from the amount of nitrate of silver originally placed in the other cell. The actual numbers were--theoretical 0.412, actual 0·402. The copper nitrate was formed in