The motors, which are of 240 H.P., consist of two coupled steam engines of the Collmann system.  The one shaft in common runs with a velocity of 60 revolutions per minute.  Its motion is transmitted by means of ten hempen cables, 3.5 cm. in diameter.  The flywheel, which is 4 m. in diameter, serves at the same time as a driving pulley.  As the pulley mounted upon the transmitting shaft is only one meter in diameter, it follows that the shafting has a velocity of 240 revolutions per minute.  The steam generators are of the Ten Brink type, and are seven in number.  The normal pressure in them is four atmospheres.  There are at present four dynamo-electric machines, but sufficient room was provided for four more.  The shafts of the dynamos have a velocity of 600 revolutions per minute.  The pulleys are 60 cm. in diameter, and the width of the driving belts is 18 cm.  The dynamos are mounted upon rails so as to permit the tension of the belting to be regulated when necessity requires it.  This arrangement, which possesses great advantages, had already been adopted in many other installations.

The electric machines are 2 meters in height.  The diameter of the rings is about 45 cm. and their length is 70 cm.  The electric tension of the dynamos measures 600 volts.

[Illustration:  Fig. 2.—­Turnout track of the electric railway, Frankfort, Germany.]

The duty varies between 80 and 50 per cent., according to the arrangement of the cars.  The total length of the road is 6,655 meters.  Usually, there are four cars en route, and two dynamos serve to create the current.  When the cars are coupled in pairs, three dynamos are used—­one of the machines being always held in reserve.  All the dynamos are grouped for quantity.

[Illustration:  Fig. 3.—­General plan of the electric works.]

The company at present owns six closed and five open cars.  In the former there is room for twenty-two persons.  The weight of these cars varies between 3,500 and 4,000 kilos.—­La Lumiere Electrique.

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By the addition of ten parts of collodion to fifteen of creasote (says the Revue de Therap.) a sort of jelly is obtained which is more convenient to apply to decayed teeth than is creasote in its liquid form.

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POSSIBILITIES OF THE TELEPHONE.

The meeting of the American Association was one of unusual interest and importance to the members of Section B. This is to be attributed not only to the unusually large attendance of American physicists, but also to the presence of a number of distinguished members of the British Association, who have contributed to the success of the meetings not only by presenting papers, but by entering freely into the discussions.  In particular the section was fortunate in having the presence of Sir William Thomson, to whom more than to any one else we owe the successful operation of the great ocean cables, and who stands with Helmholtz first among living physicists.  Whenever he entered any of the discussions, all were benefited by the clearness and suggestiveness of his remarks.