38

ELECTRICAL PROGRESS IN SYDNEY.

[FROM A CORRESPONDENT.]

SINCE I last wrote to you both the Penrith and Lambton central stations have commenced work, and are meeting with great success.

The Lambton installation was opened with great éclat by the Mayoress on October 3rd, and the day was celebrated as a gala day in Lambton, with processions, banquets, brass bands, &c., in great style.

The plant consists of two 25 N.H.P. Fowler's compound engines, working with 140 lbs. steam pressure, with boilers of locomotion type, and two 1,000 volt 650-light ThomsonHouston alternating current dynamos and two exciters.

The street lighting, running into about 25 miles of main leads, consists of 160 25-candle-power lamps, in four circuits of 40 lamps each, run in series, the lampholders being fitted with the Thomson-Houston patent paper cut-outs.

The transformers for the house circuits, ranging from five lamps to 75 lamps capacity, reducing the potential to 52

volts.

The contractors, Messrs. H. H. Kingsbury & Co., of Sydney, received £6,350 for the work.

The Penrith installation is an almost exact copy of the Lambton one, with the exception of the engines, which are Hornsby's.

The street circuits are arranged in the same way as at Lambton, in four circuits of 40 25-candle-power lamps, run in series.

The switchboards are very handsome, and arranged, of course, so that any circuit can be run from any dynamo, and either dynamo from either exciter.

There are amperemeters, voltmeters, and rheostats for each dynamo and exciter, as well as an amperemeter and bankboard for each street circuit.

On November 10th, a public holiday in Sydney, the Thomson-Houston electric tram line between Waverley and Randwick was opened, and has been running very successfully, though opinions are very varied as to the overhead wires, which are suspended from cross-wires instead of poles with cross-arms.

The line is a very nasty one, and should form a good test of the capabilities of electricity as a traction power, as there are a number of curves and gradients on it, though it is comparatively only a short line of 1 mile 30 chains, with 2 miles of track, part being single track and part double.

The track itself is not by any means of the best, having been laid down some time and used for the heavy steam

trams.

The grades go up to 1 in 10, and the curves up to 14 chains. There is one curve of 6 chains on a 1 in 18 grade.

The car is built to carry 26 passengers seated, with standing room inside and on the platforms for about 40 more. To drive this load there are two 10 H.P. motors, and on the last trip I made by it there must have been at least 30 extra passengers, and the tram seemed to go all the better for it, stopping and starting in the middle of a pretty steep upgrade as easily as on level ground.

The engine room looks very well, having plenty of room, and the switchboard is very handsome and compact.

There is one Thomson-Houston dynamo giving 500 volts. and 160 amperes running at 900 revolutions, and driven by a fine Armington and Sims engine of 100 effective horsepower running at 300 revolutions.

The boilers are old two locomotive boilers of 30 horsepower each, giving 100 lbs. pressure.

There are three cars fitted up, of which at present only one is running. The motors take a maximum current of about 36 amperes when running. The car looks quite brilliant at night with five 16 candle-power lamps to light it, one at each end, and a cluster of three in the centre. effect is rather spoilt by oil head lamps and side lights, which are used, I suppose, in case of a breakdown.

The

It is proposed to extend the line to Coogee, which is about the worst existing line in Sydney for curves and steep grades, and the Public Works Committee are at present considering and taking evidence on the question of running an electric tram line from the city to Ocean Street, along William Street

[JANUARY 9, 1891.

and New South Head Road. If this line is carried out it will be very severe test, as it is up and down steep hills all the way. The lighting of Newcastle on the Westinghouse system is proceeding apace, and the contractors, Messrs. Westcott, Marshall and Adams expect to have it completed by the end of the year. Electricians here are taking considerable interest in this installation, as it will be the first Westinghouse plant installed in the colony; and the Thomson-Houston system is installed so close by, at Lambton, which is practically a suburb of Newcastle, so that there will be an opportunity of instituting a good comparison of the two systems.

The borough council of Newcastle is at present engineering a bill through Parliament to allow them to distribute electricity to householders. It has already passed the second reading. This is the second time it has been before the Legislative Assembly, it having been thrown out ou a technical point the first time.

On October 31st the retiring governor, Lord Carrington, performed his last public ceremony in opening a school of telegraphy in connection with the electric telegraph department. The new school has been started with a view of giving present and future telegraph operators a fair knowledge of electrical science generally. (I may add that your humble servant has been appointed instructor.)

The Williamson Company seems to have made a fair start, having got the contracts for lighting two new arcades and a new theatre, and are re-wiring Her Majesty's Theatre. Our arcade from Pitt Street to Castlereagh Street is, I believe, nearly completed.

The Sydney suburbs seems to be recognising the importance of electricity as a lighting power, and great activity is being shown all round.

Tenders close to-day, December 1st; for the lighting of the borough of Redfern (which is probably more nearly part of Sydney than any other suburb, as it contains the main railway station). At Burwood, another suburb, but on the outskirts, tenders were to have been closed last week, but the date was postponed for a fortnight at the request of one or two of the leading firms.

Two or three conferences have been held by the combined councils of Marrickville, Newtown, St. Peters, Macdonaldtown, Campbelltown, Lewisham, and Petersham, assisted by many of the Sydney electrical men, and it was finally decided at the last meeting, held a few days ago, to appoint a committee with power to go fully into the question and call for tenders. This is by far the most important electric lighting scheme out of the many at present on the tapis; as the suburbs mentioned cover a large extent of ground.

The borough councils of Paddington, Waverley, Woollahoa, and Randwick have also been consulting on the same subject, and Mr. Oxlade, whom I mentioned in my last letter, has submitted a report, but, so far, nothing definite has been decided.

Still another suburb, The Glebe, has the subject before them, and have had for some time, but they have not come to a decision yet either.

At Broken Hill there seems to be quite a boom going on. Messrs. Harrison and Whiffen, the Sydney representatives of the Crompton Company, are supplying and erecting a plant for the Broken Hill proprietary mine, and Messrs. Westcott, Marshall and Adams are performing a similar service for the Broken Hill Central.

In addition to these private installations, work is going on in the erecting of a Westinghouse central station plant for the town.

Mr. Hitchcock, an expert from the Westinghouse Company, is superintending the erection of the plant for Messrs. Westcott, Marshall and Adams, the contractors.

In fact, all round great activity is being shown by the councils of the various towns and boroughs to obtain information on the subject of electric lighting, and with Tamworth, Newcastle, Young, Lambton, Penrith, Broken Hill, Burwood and Redfern before their eyes they are beginning to recognise the fact that central station lighting has passed far beyond the experimental stage in this colony, and is now an accomplished fact.

There is plenty of competition for these plums, with Messrs. H. H. Kingsbury & Co., representing the ThomsonHouston and Edison Companies; Messrs. Harrison and Whiffen, the Crompton Company; Messrs. Westcott, Mar

shall, and Adams, the Westinghouse Company; the Brush Company, and the Williamson Company, and companies in other colonies, all anxious and willing to have a finger in the pie.

I have just given a few bald facts with regard to our doings here, with the hope that you may find some items of interest to your readers.

WORKING OF RAILROADS BY ELECTRICITY.

VERY short papers followed by long discussions are an exception rather than the rule at meetings of American engineers, particularly with the Society of Mechanical Engineers. Mr. Willis E. Hall's paper on the very broad and problematic subject of working main lines of railways by electricity cannot have occupied more than fifteen to twenty minutes in reading. It is concise and to the point, the author devoting himself almost entirely to a comparison between a steam locomotive and an electric locomotive, enumerating the disadvantages of the former and the advantages of the latter. Mr. Hall points out the superior economy of stationary engines designed to work at a constant speed, utilising the highest grade of expansion as producers of of power at central stations, and which consume less than half the amount of fuel used in first-rate steam locomotives. The speed at which a locomotive engine can be driven has its recognised limits which are nearly reached. The piston speed of an engine with 24 inches stroke and 68 inches diameter of driving wheels, travelling at 60 miles an hour, would be about 1,400 feet per minute. An increase in the diameter of the driving wheels, with the object of decreasing the number of strokes, makes the engine correspondingly weaker, so that two very defined limits are placed before him who attempts to design an engine to haul the increasing weight of trains at a high speed. With electric locomotives it would not be necessary to have track tanks and water stand-pipes distributed throughout the line, which means a good deal to those who are aquainted with the attention and repairs (especially through the winter season) which such arrangements demand. Nor would it be necessary to carry the deadweight of tender containing water. No argument is necessary to indicate the advantage which electric motors would have over the steam locomotive where all the requisites of an engine must be incorporated in so many isolated places. The failures from leaky flues, broken eccentric straps, knocking a hole in the fire-box, blowing or knocking out cylinder heads, and the multiplicity of accidents which are happening every day on railroad lines, would be decreased to a marked extent. The reduction in the internal friction of the driving mechanism is also apparent. The loss in electric transmission in a station controlling a line of say 30 miles, would in the present state of the science, amount to some 50 per cent., which includes loss in dynamo, line, and that from an average working of motor. No attempt is made to show by actual figures the advantages or disadvantages resulting from the electric system, but it is merely desired to mention some of the many practical points which would be met, eliminated, or improved upon by the substitution of electricity to general railway working. Nor is it that its introduction is anticipated within a year or two; but we cannot but acknowledge that the application of electricity is becoming more general, and, from the rapidity of its development, its use for such purposes is hardly more distant than the most sanguine of its advocates would predict. The combination of electrical with mechanical engineering will bring about as much of a revolution in the future as it has done in the past, but in all its applications we must expect to see it walk before it can run.

OBJECTION TO HAULAGE BY LOCOMOTIVES.

Mr. Oberlin Smith, the president (a well-known railway engineer), touched upon a question which we have often advocated, and that is the adoption of electric motors on each car. Mr. Smith said that it is quite common, in speaking of the future of electric railroads, to assume that there must be a locomotive at the head of the train drawing the cars. This seemed to him a most absurd and ridiculous superfluity in the electric system, although with steam pro

39

pulsion the running of this enormous mass of extra deadweight was the only thing to do. The steam locomotive has developed by evolution, and is a wonderful and beautiful machine, probably the best we could have attained to so far, and doubtless destined to still greater attainments. But it has great disadvantages in the dead-weight due to carrying its boiler, fuel, water, none of which we can get over; also the limits of speed due to reciprocating motions and the difficulty of getting steam fast enough through the ports. With electric propulsion we have no such limits if we can contrive proper safeguards against derailments and collisions. Unquestionably, the future electrolocomotion will show a motor on every axle, or at any rate upon two axles of each car, and every car running as a unit, in which case they can run coupled together in a train or not, as may be convenient. Mr. Oberlin Smith most emphatically combats the idea that we must carry the enormous dead-weight of a locomotive for absolutely no reason. We have the weight of the cars, plus the passengers or freight, for purposes of traction, and this is more than abundant, even if we make our cars in future of lighter materials. In speaking of the lightness of the future conveyances by rail, the president said, that we shall not only use steel and aluminium, but paper, India-rubber, and other fibrous substances, which will give us remarkably light cars, far beyond anything we can now speak of practically. Just as a wheelbarrow is to a bicycle, so will these clumsy cars be to the future ones. To have a big motor car, loaded with tons of ballast to give it traction, is following the paths of steam locomotion, which are all right in themselves, but are totally wrong in the new field of electro-locomotion, where many of the conditions are so entirely different.

AN ARGUMENT AGAINST ELECTRIC RAILROADS, "It is safe to say that unless there are some radical changes made from the ordinary design of electric generators, and in the method of transmission of the current to the motor, as well as a motor of greater efficiency, we will never see electric railroads operated in this or any other country." Furthermore, "if steam transit would be permitted in our cities, the electric railroad business would not stand any kind of chance for competition." With these sweeping assertions Mr. F. A. Scheffler concludes his part in the discussion, which contains a lot of figures tending to prove that electric traction is and must be more costly than steam traction of the present day. We can only give a resume of those figures. According to Mr. Scheffler, the ordinary locomotive when running at the average speed with an average load does work of not less than 300 H.P. Supposing the station to be built to have a capacity, to each 30 miles of section, of not more than one locomotive, the capacity of the generating station would have to be about 360 H.P., as the best forms of motors have an efficiency of only about 85 per cent. The cost of the station, including buildings and plant, complete, would be $37,000, without duplicate machinery. For operating expenses at the station," including depreciation of engines, boilers, dynamos, oil, waste, and wages of firemen and stokers, $8,355. The cost of coal, allowing 3 lbs. per horse-power hour, $3 per ton, is estimated at $8,322 per annum. Total operating expenses at the station, $16,677. Cost and maintenance of conductors, allowing a pressure of 2,000 volts and 20 per cent. drop in pressure with 112 ampères of current. A copper rod of 1 inch diameter would be required, and as this pressure is too high to be used with safety, the return should not be made through the rails but through a second copper rod. If the circuit is 30 miles long, 476,784 lbs. of copper will be needed, at a cost of at least $162,106. Six per cent. interest on this represents $9,726. As an overhead circuit would be cheapest, and as the weight is very great, the poles should not be more than 50 feet apart, necessitating altogether 6,300 poles, costing $15,750. Allowing $4,500 for erecting the line, we obtain the sum of $20,250 for this item; again, 6 per cent. interest thereon, $1,215. Depreciation may be put down at 2 per cent., or $3,627, giving a total annual expenditure of $31,245 for the operating expenses of station plant and 30 miles line.

The cost of operating the electric motor would be about the same as steam locomotive, and the first cost also about equal in both cases. The annual consumption of fuel in the steam locomotive would amount to. 6,570 tons, costing

$18,710. Deducting this from the total operating expenses of the electric station, we find, that the difference is in favour of the steam locomotive to the extent of $12,475. The capital sunk in the station and line, complete, would be $219,856, and this amount of money would buy about 20 new steam locomotives. This is one way of showing a large balance on the wrong side which was neither supported nor successfully combatted by subsequent speakers.

ELECTRIC RAILWAYS FINANCIALLY SUCCESSFUL.

It must seem, said Mr. H. C. Spaulding, in view of the preceeding statement, that the owners and stockholders in the three hundred electric railways now in operation (in the United States alone) must be on the verge of ruin. But "ignorance is bliss," and at the present time they seem to be running along smoothly, and to have no difficulty in earning dividends. It is useless to think, nevertheless, of running long roads by electricity with the present methods, just as it would have been useless in the first days of steam engines when it was considered unsafe to use a pressure of more than 20 or 30 lbs. to get the results which we to-day get by high pressure boilers and engines. The step which will solve the problem of electric transmission for railways, will be the use of high potential current along the track, and the use of low potential motors with an induced current. As far as the tractive force of electric locomotives is concerned, we should not claim anything more than the result obtainable by steam, but what should be emphasised a little more is the entire absence of reciprocating parts in the electrical apparatus. That has been touched upon as regarding the simplicity and consequent efficiency of the machines themselves, but mention has not been made of the effect on the track, the bridges, and structures over which the locomotives are to pass. In case of the application of motors to the separate trucks, the absence of a concentrated weight is worthy of consideration. Interest in the utilisation of water power is growing rapidly, and an electric road in the South, 200 miles in length, will, within the next few years, be operated by this method, with the low potential of 500 volts.

Mr. E. P. Roberts also referred to the financial question, and said that he knew a road where they are carrying only 33 passengers per mile, receiving five cents for each person. They are operating twenty miles of double track, and are making money. On another road he knew of, the working expenses were less than 8 cents per car mile, including everything excepting interest on bonds, and that two cents covers this item.

Mr. W. E. Hall considered the figures of Mr. Scheffler far too high even at the present prices of electrical appliances. As the demand of a commodity increases the cost of production invariably decreases in proportion. As regards high tension currents, it must be admitted that vast strides have been made within the last few years. The jump from 2,000 to 10,000 volts, goes forcibly to indicate the sense of appreciation of the economical side of electric transmission. W. Forsyth stated that in getting estimates for a 7 H.P. electric motor, he found that the figures from the various companies varied from $1,100 down to $400. Probably the $400 motor was as good as that for $1,100.

MECHANIC versus ELECTRICIAN.

Mr.

Mr. S. J. MacFarren rose with some diffidence, to defend electrical methods, in an atmosphere so permeated with steam-locomotive sentiment. He congratulated the society on this commencement of the study of a subject which is growing faster than many realise. His experience has been that the electricians, so called, are not mechanics. A well known system of electric motors has been pronounced a mechanical failure in a careful report made by experts for a syndicate. These experts state that the gentleman who gave name to this company, and who had worked out the mathematics of electricity better than any competitor-that he so exhausted his brains on the electrical features as to leave nothing for the mechanical details of the problem, and has not yet reached a place where he can guarantee any sum which will cover the cost of repairs to the gearing and mechanism of his motor. Mr. Scheffler has proved by very skilful argument that it is impossible to operate a railroad by electricity. But it becomes constantly less safe to define possibility. Electricity is in no sense a rival, but in every sense an aid, to steam. There never was an industry com

[JANUARY 9, 1891.

manding the amount of investment the electric railway has to-day which was guided by such ignorant advice as it is dependent upon. No more inviting field than electric propulsion opens for mechanical engineering, since 90 per cent. of the features of so-called electric "systems are mechanical features. Sir Wm. Thomson has well said that the mechanical engineer needs to add but one-tenth to his knowledge to include the electric field.

Mr. T. M. Sweeny thought that in the consideration of the subject before the society the fact is lost sight of that electricity is merely a ready means of transmitting energy instead of a belt or a rope or other methods which have been employed at various times. The remark made by Mr. Scheffler, which was to the effect that, if steam cars were allowed to be run through the streets of cities, they would instantly supplant electric traction, was rather erroneous. That can hardly be possible, because for street traffic a higher class of labour is required to take care of and manage the steam locomotive than to take care of and manage an electric motor, and it is that feature which makes electricity so particularly applicable to street traffic. One can pick up a class of labour and educate it in a short time to handle the electric motor. There is too much disposition on the part of mechanical engineers to conclude that a requisite for electrical application is a lack of mechanical engineering knowledge. For a time, Mr. Sweeny was of that opinion, and thought that it would be but little trouble to correct many of the weak places in mechanical details, but he has generally found that they are too closely allied with the electrical question, and that what would certainly be a successful device if electricity was left out of the question, became anything else when connected with the electrical end. There is a great field for mechanical engineers in working out the details of the adaptation of electricity. But, in order to be successful, the engineer must also know a great deal of the properties of electricity.

THE ACTION OF ELECTRICITY ON MICROBES.

ELECTRICITY appears to be a determined enemy to microbes. The first researches concerning the action of electricity on microbes were carried out by M. Schiel, and go back to 1875. Observing that under the influence of the electric current certain mobile bacteria ceased to move, the author therefrom concluded that the electricity had killed them; but it is now known that immobile microbes are not dead microbes. Thus MM. Cohn and Benno-Mendelsohn again took up these researches, bringing thereto this corrective, that the microbes were not considered as dead only so far as their sowing was sterile. The experimental process employed by these gentlemen specially consisted in passing through a U-tube containing the nutritive solution the current from a few elements of a Marié-Davy pile. The nutritive solution had been sown previously, and when it became thick it was concluded that the current had remained without action.

In thus conducting their experiments, MM. Cohn and Benno-Mendelsohn saw that the effect of a weak momentary current was always nil. With a longer and a more intensive action, for instance, with the current from two powerful elements for twenty-four hours, the liquid near the positive pole remained intact, but the bacteria were not killed. It seemed even that this was the liquid which had become sterile, for it did not let a new sowing which had been introduced multiply, and, in reality, it had become strongly acid. With a current from three elements for twenty-four hours, there were at one and the same time observed at the two. poles the death of the bacteria and the sterility of the liquid traversed by the current. But as it produced a profound chemical change in the cultivation, it was not possible to draw any conclusion relative to the direct action of electricity on the microbes. The experimenters, in order to avoid these decompositions produced by the current, then tried induction currents, but without obtaining appreciable results. With cultivations on potatoes, the chemical changes also occurred. The recent experiments of MM. Apostoli and Laquerrière, whose experimental preparations were not suffici

JANUARY 9, 1891.]

ently described, but who appear also to have used a U-tube, have not advanced the question.

In order to free themselves from these causes of error, MM. Prochownick and Spoeth made use of an ordinary vase in bringing the electrodes together; the currents produced in the liquid by the gaseous emanations, while easily mixing the layers, constantly re-combining the elements dissociated by the current, and thus producing an average and persistent state, the duration of which was of only second importance. The authors, however, in acting by this process on the hay bacillus, the pus micrococus, and the carbuncled bacteria, only obtained insignificant results. In short, as M. Duclaux remarks, in all these experiments, if any sensible action has been found, it must be put down as a chemical action, and hitherto no one has been able to place in evidence a physical, direct action of electricity on microbes.

THE ELECTRIC LIGHT AT TURN.

[FROM A CORRESPONDENT]

THE Community of Turn, in Bohemia (not far from the watering place Teplitz), in a municipal meeting held on December 17th, 1890, resolved on the introduction of the electric light, and for this purpose concluded an agreement with the Board of Inspection of Prince Clary's estates. The latter body stipulates to begin the erection of the electric central station within six months at the latest.

The community of Turn is certainly only a small town, as appears from the circumstance that for the public lighting of the streets, lanes, and open spaces only 55 glow lamps are projected, each of 55 normal candle-power, which are to burn for 5 hours during 250 evenings yearly. But Turn is a rising community with a prosperous industry, and as the projected electrical works are also to furnish current for the production of motive power, all the conditions for a lucrative development are present.

The agreement is made very favourable for the party supplying the current, and it contains some noteworthy stipulations, providing for an interruption of the work by external interference, such as, e.g., the outbreak of a strike.

The most important stipulations are the following:-The community of Turn concedes to the Inspection Board of Prince Clary's estates the right to utilise the streets, lanes, and open spaces within the parish of Turn (in as far as it possesses the right of disposing of them) for laying down leads for conveying electric energy, whether above or underground, for the purposes of lighting, and for the transfer of power.

The community of Turn renounces the right, during the existence of this agreement, to allow any third party to make use of such streets, &c., for laying down leads for the conduction of electric energy for the distribution of light and power, or for the conveyance of any other illuminant, or to make use of such a right themselves.

The community of Turn commits to the above undertaking, for the duration of the concession, the exclusive lighting of the streets, lanes and open spaces, and pay for this lighting by means of 55 glow lamps, at 25 normal candles each, during 250 nights, for 5 hours' burning, a yearly contribution of 1,375 florins.

The administration of the Clary estates is bound to supply the parish of Turn with electric light for its buildings and institutions, on the following conditions :

(a) The community of Turn has to pay monthly the following fundamental tax for every glow lamp at 10 normal candles, florin; if at 25 to 32 normal candles, 55 kreuzers; if from 50 to 100 candles, 60 kreuzers, and for an arc lamp, florin (50 kreuzers) per ampère. A reduction will be conceded in the case of lamps connected to an electric meter of 15 per cent. for lamps burning above 600 hours; 30 per cent. for more than 700 hours; 50 per cent. for 800 hours; 65 per cent for 900 hours; 80 per cent. for 1,000 hours, and 100 per cent. (?) for 1,100 hours and upwards.

(b) As regards the price for lighting, the parish of Turn has to pay for every burning-hour, per glow-lamp of 10

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candle-power, 18 kreuzers; of 16 candles, 23; of 25, 38; of 30, 5 kreuzers; of 50, 8 kreuzers; for an are lamp at 6 ampères, 18 kreuzers; and at 8 ampères, 27 kreuzers.

(c) The current supplied will be measured by meters, for which a charge will be made of 10 florins up to 10 instruments, of 16 florins up to 25, of 20 up to 30, of 25 florins up to 100, &c.

(d) At the above-mentioned prices the Inspection Board of the Clary estates allows the community of Turn a discount of 10 per cent.

The said Inspection Board reserves the power of making agreements with the inhabitants of Turn for the supply of electric current, and fixing prices which may admit of the greatest possible consumption of current by private persons. The prices fixed for private consumers, however, must not be lower than those fixed for the community. Otherwise the community has the right to demand its supply at the lowest rate fixed for private consumers.

Until the central station is set at work, and whilst the leads required by the community for its buildings, &c., are being laid down, leads for private consumers will be laid down up to the front of the house without any extra charge. After this time connections from the nearest point of the main cable will be made at the cost of the applicant. This stipulation does not apply to public lighting.

On the conclusion of the agreement the community of Turn will be supplied with a plan of the situation of the central station, and of the projected conductive net for the supplying the current.

The installations, i.e., the fitting up and repairing the leads and other fittings in the interior of houses must be executed exclusively by the central station on a scale of prices which is to be agreed on yearly with the community. Such fittings as lamps, chandeliers, brackets, &c., are not included in the installation. The prices in the scale just mentioned must be neither higher nor lower than those which the city of Vienna pays at any time to the International Company or other works there, but with the addition of 10 per cent. This tariff includes the prices for street cables, electric meters, the fittings of glow and arc lamps, and the carbons which will be supplied from the central station. These glow lamps will be supplied for a monthly rent of florin each, which includes the gratis replacement of lamps which have been worn out. The fittings for public buildings may be obtained from any source, but Prince Clary's estate Inspection Board has of testing if the conducting wires are suitable and if the the right lamps are properly connected.

All damage to the streets and pavements occasioned in laying down the leads, &c., are to be made good by the central station without delay. If it does not at once comply with the request of the community in this respect, such repairs may be at once executed by the community at the cost of the central station.

The central station can never be held responsible for interruptions in the supply of current due to war, rebellion, strikes, or natural calamities, such as floods or conflagrations, or to the malice of third parties, or which may arise from unforeseen defects in the machinery. But in these cases the Estate Inspection Board is at once to give notice to the community.

Penalties are imposed for any non-observance of the duties imposed upon the Estates Inspection.

Disputes arising from this agreement are to be decided by expert arbitrators, who must not be in a position to be influenced by either party. Each party has to appoint an expert arbitrator, and these arbitrators select an umpire.

No legal appeal may be taken against the decision. The Estate Inspection Board has not the power to cut off the current entirely, or partially during any dispute.

The agreement is to last for 25 years, counting from the day when the installation is set in action. The prices fixed as above are to hold good for 10 years only. Three months before the expiry of these ten years a new agreement as to prices must be come to by the contracting parties for the next ten years, and after the lapse of this second five years the prices for the remaining 5 years must be arranged.

If the Clary Estates Inspection Board does not begin the construction of the central station within six months from the day of signature of this agreement, the latter becomes null and void.

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SOME MEASUREMENTS THAT ARE CONVENIENTLY ACCOMPLISHED IN PRACTICE BY THE WESTON HIGH RESISTANCE VOLTMETER.*

BY OSBORN P. LOOMIS.

IN the following I have attempted to give a practical description of some methods of applying a high resistance voltmeter to the ordinary measurements that occur in the everyday life of the electrical engineer. It is attempted to make them as clear as possible, and probably more so than is necessary to many, who may also have used the same method with various modifications; to others, however, they may prove of interest and value.

The first application I will mention is that of measuring approximately the insulation resistance of line work, &c. In the diagram, fig. 1, is shown a system of wiring in which we

X

[JANUARY 9, 1891.

Here is an example;

Subject in circuit, 140 volts, v.

Voltmeter alone, 149 volts, V1; resistance of voltmeter, 16,660 ohms, R. Applying the formula, 149 × 16,660

140

· 16,660 = 1,731

-

1,660 = 1,071 ohms. If the circuit closing key is opened while the subject's hands are in the solution, the sudden shock will be very unpleasant but by immersing the hands while the current is on it can be endured quite readily, as the volume of current will probably not exceed 9 milliampères with 150 volts on the voltmeter. It is, of course, obvious that a high resistance voltmeter is absolutely necessary in these measurements; in fact, the higher it is, the better.

I will here mention a simply made storage battery for these and other measurements. Procure about 72 largemouthed bottles, about 2 inches in diameter and 6 or 8 inches deep. Make the plates of lead strips with other very narrow strips of lead wound around the portion which is immersed in the acid. To save the trouble of numerous connections, make one strip long enough to reach over into both bottles with the afore-mentioned wound portion on each end. The arrangement is shown in fig. 3. They are usually

The line insulation resistance is therefore equal to 83,300 ohms.

In this manner insulation resistances may be measured up to one megohm and at any time while the circuits are in operation, the convenient connecting switches being permanently arranged on the switchboard. In this way interesting data can be obtained regarding the effect of different states of weather on the line.

This principle can be applied to the measurement of the resistance of the human body, and it is a much more desirable method than by the Wheatstone bridge. Fig. 2 shows the arrangement in detail.

FIG. 2.-MEASURING RESISTANCE OF THE HUMAN BODY.

Two glass jars are provided, each containing a weak solution of caustic potash, and copper plates connected in series with the voltmeter and dynamo, or a battery of small storage cells to be described later. It is desirable to run the voltage up as high as the subject can endure, which may be 140 volts.

• New York Electrical Engineer.

this battery is in photometry work; as the current gradually falls, it is started at a higher E.M.F. than the standard, and the screen watched when the balance is obtained; then a signal is given and the E.M.F. and current are read by other parties, so that the efficiency for any given candle-power is obtained.

We now come to the internal resistance of batteries, in which no ammeter is required, but a standard resistance, fig. 5, made of heavy German silver or platinoid wire, about No. 7 or 8 gauge. Ten spirals wound right and left handed and placed alternately, to avoid magnetic effect as far as possible, are arranged to be connected in series or multiple by large brass screws. By this arrangement it can be measured in series or multiple and any error can be found that might exist where only the low resistance could be measured. This resistance is conveniently adjusted to Too of an ohm in multiple; in series it would be 1 ohm measured in legal units. In this combination a variety of work can be accomplished.