With an energy consumption in the generator of 100 watts, the yield of ozone is about 4 grms. per hour at a concentration sufficient to sterilise water, bleach oils, &c. The capacity for bleaching in a day of ten hours is about 50 lbs. of material, and for sterilising water about 4000 gallons. Naturally at lower concentrations the yield will be greater, and vice versa.

A useful form of experimental apparatus for the lecture table is shown in Fig. 2. It consists of a small generator enclosed in a bell-glass and mounted upon a glass-faced iron tripod stand with a stopcock; the neck of the bellglass is fitted with a cap and carries the high tension terminal and draw-off tube for the ozone.

In addition to generators aad electrical apparatus the Company supply complete sets of glass aspirators, dryingbottles, and experimental chambers for carrying out researches upon the effects of ozone; one of these plants is shown in Fig. 3. We have recently had occasion to use one of the Company's generators for some experiments upon the bactericidal action of ozone, where freedom from the oxide of nitrogen was essential, and we found the ozone pure and the method of generating it easy and trustworthy. In these special experiments over 90 per cent of the microbes were killed.

The Ozonair Company are prepared to give advice and to design plants for the production of ozone upon any scale and for any purpose that may be required, and at their laboratories a staff of experts can be consulted and experimental work carried out by arrangement.

THE SIR JOHN CASS TECHNICAL INSTITUTE. THE Inaugural Lecture of the courses of instruction in "Fuel" was given by Mr. J. S. S. BRAME, Lecturer on Fuel, at the Institute, on Monday, October 10th. The subject of the lecture was "Power Gas and its Development." The Chair was taken by Prof. F. CLOWES, D.Sc., Past-President of the Society of Chemical Industry, who, in introducing the lecturer, pointed out the technical importance of the modern developments of power gas, and referred to the value of the instruction that is provided at the Institute for the study of the applications and analytical examination of all forms of fuel.

Mr. BRAME pointed out that the introduction in quite recent years of power gas, whereby the heat units available in our fuels are converted into work without the intermediary of the steam-engine, has been a factor of immense economical importance, and the extension of this method of applying our fuel will, in the near future, exercise an even greater influence in reducing the cost of power, and thus enabling us to conserve our vast, but nevertheless limited, supplies of coal.

The total coal production for 1909 was 263,758,000 tons, and our annual home consumption some 180,000,000 tons. It is difficult to estimate how this consumption is distributed, but we may roughly compute that 45 millions are utilised for power purposes, 20 millions for blast furnaces, whilst some 17 millions are carbonised for the production of gas. It is unlikely that the consumption in gas works will decrease, but the introduction of the large gas-engine is rendering much of the available power from blast-furnace and coke oven gas-equivalent to some 1,250,000 horsepower per day-of service, thus leading to very considerable fuel economy; indeed one English firm is saving about £1000 per week on these lines, and on the Continent the Differgingen Iron and Steel Works effect a fuel saving of £75,000 in the year.

It is to the demand of coal for power purposes that we must turn to realise the economies which are possible through the introduction of power gas. As compared with the steam-engine the consumption of coal per B.H.P. is

sumption by 9 million tons by substituting power gas, a national saving of 20 per cent on the coal used for power would be effected. Further, the power gas plant is rendering economically available for power purposes immense stores of fuel which could not otherwise be applied. One ton of dry peat, for example, yields some 1000 B.H.P. per hour, together with from 70 to 200 lbs. of sulphate of ammonia, worth £11 to £12 per ton. When it is remembered that in Europe there are some 140 million acres of peat bog, often 14 to 16 feet in thickness, the utilisation of a small portion of the energy here stored up would effect a large saving of coal for other purposes.

The possibilites of power gas are being rapidly recognised, as is evident by the enormous advances made in its introduction in large and small works in recent years. Where gas for heating purposes as well as power is demanded, it offers so many advantages that its installation into steel works, ship-building firms, and similar industries already amounts to many thousand horse-power. As regards fuel costs, the efficiency of power gas is approximately 20 per cent, whilst with steam 9 to 10 per cent is a fair average.

An outline of the general principles underlying the action of gas plants was then given and the general arrangement of plant illustrated, the various forms of pressure plants and suction plants being described.

For small powers suction gas is not a competitor with pressure gas from bituminous fuels, since gas plants using this class of fuel are unsuited for small powers by reason of their higher first costs and working charges.

The pressure plants for non-bituminous fuels offer great advantages where gas is required for heating in addition to power. Pressure gas is usually somewhat richer than suction gas and is more uniform in composition, since its production is continuous whilst the latter is intermittent. Pressure systems usually are provided with a holder which enables more uniform gas to be stored, supplies good gas to the engine after a stand-by or working on light load, and eaables gas to be distributed to several engines and to furnaces for heating.

On the other hand, for small power plants only, up to some 250 horse-power, the suction gas plant offers so many advantages, such as compactness, low cost, simplicity of working, that its rapid introduction throughout all countries is easily understood. Hitherto the choice of fuels has been limited to anthracite (the demand for which has greatly raised the price) and good quality coke. The use of bituminous fuel, with its manifest advantages in the matter of supply and price, has until quite recently been impossible owing to the difficulty of removing the tar from the gas, but practically all the leading makers now supply suction plants which it is claimed work well with such fuels, the general principle involved being the destruction of the tar by causing the distillation products from the coal to be drawn through the hottest zone of the producers where the resulting coke is being gasified. In Germany suction plants working on fuels containing sufficient moisture for the producer reactions-lignite, peat, &c.-have been successfully employed.

In comparing the relative merits of coal-gas and suction gas for small power plants detailed estimates of cost were given, which showed that little advantage is obtained by the adoption of suction gas when cheap town gas is available, what little gain there is being quite counterbalanced by the convenience arising from town gas supply and total absence of stand-by charges. Above 30 horse-power the advantage of suction gas, however, rapidly increases.

The success of the suction plant working on bituminous fuels, even of the most unpromising character, is now established, and the extension of the use of this type of plant is likely to be very rapid. Systems of scrubbing the gas will be improved when it is realised that such a process is essentially not a filtering one. The utilisation of the exhaust from the engine in lieu of steam through the producer has given promising results, the poor quality of gas

A periodic classification I suggested (CHEMICAL NEWS, c., 281, Table IV.) lends itself to a grouping in accordance with these results. The metals in Groups II. to VIII. inclusive-upper division of the table, including Ce, do not disintegrate. Mn is, however, an exception. The metals in Groups II. to VI. inclusive, lower division of the table, disintegrate into powders. All the metals of Group I., except Cu, disintegrate, although Au and Ag do so but slightly.

If the table is wrapped round a cylinder, so that the bottom row (VII.) is brought_round next to the top row (Li, Na, &c.) the metals that disintegrate are of one block or section, and those that are stable are of another similar section. K should be regarded as filling the gap between Na and Rb. The metals of the rare earths from Pr to Lu (Cp) inclusive, have, of course, not been examined.

-I am, &c.,

F. H. LORING.

Hydrazi-zinc and Preparation of Metallic Hydrazides.-E. Ebler and R. L. Krause. - When zinc methyl or ethyl acts on anhydrous hydrazine in presence of ether an unstable hydrazi-zinc of formula ZnN2H2 is obtained. From zinc diamide the same compound can be prepared similarly, and it has been found that many other metallic diamides react with hydrazine to give the corresponding hydrazides, which are of special interest because by their slow oxidation the diazo metals are obtained.

Atomic Weight of Tellurium.-W. Marckwald and A. Foizik.-Marckwald has found from the conversion of telluric acid H2Te04+2H2O into the dioxide TeO2 that the atomic weight of tellurium is 126 85, while the value given by the International Atomic Weight Commission is 127 5. Brauner oxidised TeO2 in alkaline solution by permanganate in excess, acidified with sulphuric acid, added

SOURCES.

Berichte der Deutschen chemischen Gesellschaft. Vol. xliii., No. 9, 1910. Carbon Nitrogen Bond.-Heinrich Biltz.-By the study of compounds in which carbon and nitrogen are directly linked the author has found that if the basicity of the nitrogen is increased by means of suitable substituents the affinity of the nitrogen for the carbon increases, while if the acidity of the carbon is increased its affinity for nitrogen is also raised. Similar phenomena seem to occur in compounds in which two carbon atoms are directly linked.

Tantalum Sulphide.-Heinrich Biltz and Carl Kircher. -At comparatively low temperatures the action of carbon

The value he obtained was 127.05. The author has repeated these experiments with some modifications, using iodine and thiosulphate for the back titration, and gets a result agreeing very well with that given in the International Atomic Weight Table. Possibly the values given from the conversion of telluric acid into the dioxide were too low owing to the formation of a solid solution of the telluric acid hydrate with a higher hydrate.

No. 10, 1910.

So-called Euxen-earth. Otto Hauser and Fritz Wirth. The examination of all the important zirconium minerals shows that zirconium earth is a single substance, and there is no indication of the existence of a similar earth accompanying it—the so-called euxen-earth. Many zirconium earths are radio-active, even when they are quite free from thorium.

Wilhelm Silberstein.-Oxalic ester condenses with propionitrile easily in an alcoholic ethereal potassium ethylate solution, the product being the potassium compound of CH3 propionitrile-oxalic ester, 3>CH.CO.COOC2H5. The N free ester can be obtained from the potassium compound by treatment with ice-cold sulphuric acid.

Ester Condensations. Wilhelm Wislicenus and

Metaphosphoric Acid Ethyl Ester. K. Langheld. By boiling phosphorus pentoxide for three days with excess of ether previously dried over sodium, metaphosphoric acid ethyl ester can be obtained :C6H5.O.C2H5 + P2O5 2C2H5O.PO2. This compound seems likely to be extensively applied in organic chemistry on account of its power of forming addition products and its condensing action.

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