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The liquefied milk is slightly concentrated by evaporation, and to the new product so obtained the name of galacton' has been given. The investigation in regard to any enzyme being formed by the Bacterium peptofaciens gave the result that this is not the case. As compared to the meat peptones now largely used, the galacton has the advantage of containing no gluten-peptone, which probably explains the much better taste; further, that no chemicals, such as hydrochloric acid, are required in its preparation.

Formerly it has been supposed that milk-sugar could only undergo acid fermentation, but lately special yeasts have been found which produce alcoholic fermentation of milk-sugar. By means of such yeasts an alcoholic beverage can be made out of galacton.

The author concluded with the remark that bacteria have of late been most conspicuous in the minds of most people by the fact that, out of the enormous number of bacteria existing, there are a few which have pathogenic effect. But the action of bacteria in nature is an eminently useful one, and by the chemical study in this direction we shall learn how to utilise their peculiar action to our advantage.

FRIDAY, AUGUST 10.

A discussion on the behaviour of gases with regard to their electrification and the influence of moisture on their combination was opened by the reading of the three following papers :—

1. On the Connection between Chemical Combination and the Discharge of Electricity through Gases. By Professor J. J. THOMSON, M.A., F.R.S.

[This paper was ordered to be printed in extenso.-See Reports, p. 482.]

2. On the Electrification of Molecules and Chemical Change.
By H. BREREton Baker.

[This paper was ordered to be printed in extenso.-See Reports, p. 493.]

3. On the Rate of Oxidation of Phosphorus, Sulphur, and Aldehyde. By THOMAS EWAN, B.Sc., Ph.D.

Gaseous oxygen appears sometimes to be more active chemically in the dilutestate than when it is more concentrated. This remarkable behaviour was studied in the cases of phosphorus, sulphur, and aldehyde, by the author in Professor van't Hoff's laboratory in Amsterdam.

With phosphorus and oxygen (saturated with aqueous vapour at about 20°) it was observed that for pressures of oxygen greater than 700 mm. the rate of oxidation was excessively small or nothing at all. Below 700 mm. it increases rapidly. This limit corresponds with that found by Joubert, below which phosphorescence begins. After reaching its maximum velocity a very simple relation exists between the rate of oxidation and the pressure of the oxygen, provided that the change in the rate of evaporation of the phosphorus, which, according to Stefan, is produced by the change in the pressure of the oxygen, is taken into account. The rate of oxidation is then directly proportional to the pressure of the oxygen. In the absence of water the oxidation also begins suddenly, but at a much lower pressure (about 200 mm.). Again allowing for the change in the rate of evaporation of the phosphorus, the velocity of the reaction quickly reaches a maximum and then decreases, as nearly as could be made out, proportionally to the square root of the pressure of oxygen. The results here were not so certain as might be desired, owing to the layer of oxide formed on the surface of the phosphorus disturbing the regular course of the reaction.

1894.

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With sulphur in dry oxygen, where the course of the reaction can be conveniently followed at 160°, it appears (again allowing for the change in the rate of evaporation) that the velocity of the reaction is proportional to the square root of the oxygen pressure.

No limit was observed here up to 800 mm., beyond which no observations were made.

To eliminate the uncertainty introduced by the correction for the rate of evaporation of the phosphorus and sulphur, the reaction between the vapour of acetaldehyde and oxygen was studied (at 20°). The reaction was found to go perfectly regularly, and its velocity was proportional to the product of the pressure of the aldehyde vapour and of the square root of the pressure of the oxygen gas.

The interpretation of these facts would appear to be that only that small part of the oxygen which is broken up into atoms takes part in the oxidation.

4. New Methods of Spectrum Analysis, and on Bessemer Flame Spectra. By Professor W. N. HARTLEY, F.R.S.

This communication comprises three parts:-

1. On the Separation of Spectra of the Alkalies from those of the Alkaline Earths. This is accomplished by fusing the material with boracic acid, hydrated silica, or dissolving in hydrofluosilicic acid. The salts so formed are used in the ordinary manner in a Bunsen flame.

2. Methods of obtaining Spectra with Flames at High Temperatures.-The difficulty of obtaining spectra at high temperatures arises from the necessity of having a support for the substances to be examined which is practically infusible in the oxyhydrogen flame. The mineral kyanite from County Donegal is suitable for supports in the oxy-hydrogen blow-pipe flame. A commoner material is ordinary tobaccopipe, which serves as a support for various metallic salts. The spectra obtained in the oxy-hydrogen flame have the following characters, by which they may be classified :

(1) Lines: lithium, thallium, nickel, cobalt.

(2) Bands: antimony, bismuth, gold, tin, sulphur, selenium.

(3) Bands and lines together: copper, iron, manganese, tellurium, lead, and silver.

(4) More or less continuous spectra with lines: sodium, potassium, magnesium, chromium, cadmium.

(5) Continuous spectra: zinc, carbon, arsenic.

(6) No spectrum: platinum.

Band spectra can be converted into line spectra by reducing the quantity c substance in the flame. This is shown by the lines of silver which are found to be present in spectra obtained from ordinary copper; the spectrum of silver being itself a band spectrum. A distinct flame spectrum may be emitted by compounds at high temperatures. Examples of such spectra are those of magnesia, lime, copper-oxide. Some compounds emit only the spectra of the metals they contain: such are compounds of iron, nickel, cobalt, chromium, manganese, sodium, potassium, lithium, thallium, and rubidium.

3. Bessemer Flame Spectra.-Up to the present time the precise nature of the spectrum, the cause of its production, its sudden disappearance when decarburisation of the metal takes place, and the connection between the decarburisation of the metal and the extinction of the spectrum. have not been satisfactorily explained. According to Roscoe, Lielegg, Kupelwieser, and Spear Parker, the spectrum is characterised by bands of carbon or of carbon monoxide, which disappear when all carbon is burnt out of the metal.

On the other hand, according to the investigations of Simmler, Brunner, von Lichtenfels, and Wedding, the spectrum is not due to carbon (Roscoe), or to carbon monoxide (Lielegg and Kupelwieser), but to manganese and other elements in the pig-iron.

The very careful examination of these spectra by Watts, and his comparison of

them with that of the Bessemer flame, led to the conclusion that it was not the spectrum of carbon in any form, or of manganese, but that of manganic oxide.

The spectrum is a complex one, which exhibits differences in constitution during different periods of the 'blow,' and even during different intervals in the same period. As originally observed by Watts, the spectrum differs in different works, the difference being due to temperature and to the composition of the metal blown.

During the First Period. The lines of the alkali metals, sodium, potassium, and lithium, are seen unreversed on a bright, continuous spectrum caused by carbon monoxide. The C line of hydrogen, and apparently the F line, were seen reversed during a snowstorm, when much moisture entered the metal with the blast.

During the Second Period, the 'Boil.'-Bands of manganese are prominent, overlying the continuous spectrum of carbon monoxide. There are lines of carbon monoxide, manganese, and iron, also those of the alkaline metals.

During the Third Period, the Fining Stage.'-The spectrum is the same as the foregoing, but the lines of iron are not so strong and not quite so well defined. Some of the short lines of iron disappear; the lines of the alkali metals are visible.

The alkali metals do not show themselves in the Bessemer flame until a layer of slag has been formed and the temperature has risen sufficiently high for these basic constituents to be vaporised. At the temperature of the boil,' or second period, both metallic manganese and iron are freely vaporised in a current of carbon monoxide which rushes out of the bath of molten metal. The evidence of this is the large number of bands of manganese and lines of iron in the spectrum.

When the metal blown contains but little manganese, the manganese spectrum in the flame does not arise from that substance being contained in the bath of metal; it must be vaporised from the slag. That this is so has been proved by photographs of the spectrum from samples of slag obtained from the Crewe works. This explains the fact observed by Brunner, namely, that when a converter is being heated with coke after it has been used, but not relined, the spectrum of the Bessemer flame makes its appearance; manifestly it comes from the adhering slag.

The luminosity of the flame during the boil' is due, not merely to the combustion of highly heated carbonic oxide, but also to the presence of the vapours of iron and manganese in the gas.

The disappearance of the manganese spectrum at the end of the 'fining stage,' or third period, is primarily due to a reduction in the quantity of the heated carbon monoxide escaping from the converter, which arises from the diminished quantity of carbon in the metal. When the last traces of carbon are gone, so that air may escape through the metal, the blast instantly oxidises any manganese either in the metal or in the atmosphere of the converter, and furthermore oxidises some of the iron. The temperature must then fall with great rapidity.

The entire spectroscopic phenomena of the 'blow' are undoubtedly determined by the chemical composition of the molten iron, and of the gases and metallic vapours within the converter, the temperature of the metal, and that of the issuing gases.

The Temperature of the Bessemer Flame.-The probable temperature of the Bessemer flame at the finish is that produced by the combustion in cold air of carbonic oxide heated to about 1,580° C.-that is to say, to the temperature which, according to Le Chatelier,' is that of the bath of molten metal from which the gas has proceeded.

5. On the Chemistry of Coal Formation.

By J. W. THOMAS, F.I.C., F.C.S.

The age of the coal, and the physical conditions, such as the effect of water, heat, and pressure, should throw light upon the chemistry of coal formation; but Comptes Rendus, vol. cxiv.

the coals in one 'field' are found under different physical and chemical conditions from those of another, and little evidence is obtained by comparison.

The decomposition of peat and of wood teaches us more of the chemistry of coal formation. In both instances the woody fibre disappears first, leaving a residue richer in resinoids. The lignites of Bovey Tracey have, as in the case of decaying peat and wood, an excess of resinoid matters over the vegetation which formed them. Hutton found mineral resin in Carboniferous coals, and others since. Witham showed long ago, and much recent evidence proves, that conifers and other dicotyledons flourished during the Carboniferous period. Just as lime and other trees shed saccharine matter on the leaves and grass underneath, so it is probable that liquid, gummy, and resinous matters were showered from the forest vegetation during the Carboniferous and Tertiary periods.

The chemical changes in coal formation took place chiefly at and near the surface. In the formation of paraffin shale and some Scotch cannels the woody fibre of the forest growths was destroyed, little else but bituminous matters remaining. A resinous vegetation without much dicotyledonous trees, or if with dicotyledons, considerable surface exposure and decomposition of the woody fibre, would produce rich bituminous coal, Wigan cannel, &c. A luxuriant resinous and dicotyledonous vegetation, assisted by heat and pressure, without much surface decomposition, probably gave rise to semi-bituminous, steam, and anthracite coal. Our present chemical knowledge of coal may be summed up as follows:1. It contains water after air-drying. The hygroscopicity of coal has not received due attention. The water is in chemical combination. Further, the hygroscopicity is most probably the key to the spontaneous combustion of coal.

2. Coal contains the gases, liquids, and solids of the paraffin series, but these together will not make up more than 1 per cent. of Carboniferous coals.

3. The bulk of coal is carbon, with more or less hydrogen, oxygen, nitrogen, sulphur, and ash. We shall probably never know how the carbon is combined or how much is in the free state.

Further experiments are suggested as follows:

1. Upon the decomposition of dicotyledons to throw light upon the formation of coal.

2. Upon the hygroscopicity of coal; and to study its bearings upon the spontaneous combustion of coal on board ship.

3. Upon coals from all British coal-fields, to determine the quantity and, if possible, the constituents soluble in gasolene (petroleum ether) or benzine as employed by Mr. Watson Smith.

4. To act upon the various coals with a weak solution of potassic hydrate.

6. On the Iodine Value of Sunlight in the High Alps. By Dr. S. RIDEAL

At the meeting of the Association in Nottingham I had an opportunity of submitting the values of the sunlight in the Upper Engadine in terms of the amount of iodine liberated from an acidulated solution of potassium iodide during the month of January 1893. These experiments have been continued during the months of January and February of the present year by my brother, A. W. Rideal, and the results may therefore not be without interest. The recent experiments were conducted in exactly the same way as those of last year, so that in all respects they are strictly comparable.

The solutions were standardised by standard iodine solution prepared in England, and the hyposulphite solution was checked against this solution from time to time during the progress of the experiments.

During the last winter the weather was, on the whole, bad, and the number of days on which snow fell or which were overcast were more numerous than in the corresponding period of last year.

The maximum value was obtained on February 4, and was equal to 14:52 mgms. of iodine per 100 c.c., as compared with 135, the maximum value on January 1, 1893. The lowest value was 3.53 on December 9, 1893, as against 5-7 on

January 24 of last season. The number of bad days on which little or no sun was recorded lowers the average for the period under examination. It amounts to 7.05 mgms. per hour, whilst in January 1893, taking only the bright days, the quantity was 9.34.

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I understand that the ordinary meteorological record was kept as usual, and that the data are to be found in the Alpine Post' for the days on which these experiments were carried out. I append, however, a brief note as to the atmospheric conditions in a separate column.

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