242 



SCIENCK 



[Vol. XIV. No. 348 



abroad ; and it is no unusual thing to hear of another mining com- 

 pany which has decided to adopt electric power in its mines. 



Among recent contracts which have been awarded the Sprague 

 Electric Railway and Motor Company of New York for electric- 

 mining apparatus is one which comes from Transvaal, South 

 Africa ; and it is interesting to note that the fame for American 

 electric-mining apparatus for durability, economy, and convenience, 

 is recognized in these fields as well as in this country. The com- 

 pany which is now installing Sprague apparatus in Transvaal is 

 the Forbes-Reef Gold-Mining Company, who have ordered through 

 Chester & Gibb, mining engineers of London, Eng., a complete 

 electrical equipment for transmitting power, including four Sprague 

 long-distance motors, and dynamos for transmitting 140 horse- 

 power over a distance of three miles. The primal source of power 

 is a waterfall situated about three miles distant from the mines 

 as the crow flies. These points are connected by insulated wires, 

 which are carried on poles. 



At the power-station will be placed three Pelton wheels fur- 

 nished by Frazer & Chalmers of Chicago. To each of two of these 

 wheels will be belted one long-distance transmission constant po- 

 tential Edison dynamo of 50,000 watts, or 67 horse-power, capacity 

 each. To the other wheel will be belted a dynamo of the same 

 type and voltage as the others, but of only 40,000 watts, or 55 

 horse-power, capacity. These dynamos are similar in appearance 

 to the standard Edison dynamo which is used in incandescent 

 lighting ; but their winding is modified according to the regular 

 Sprague system, adapting them for the long-distance transmission 

 of power. These machines have an efficiency of over 95 per cent. 



At the mines are located the four Sprague motors, which are 

 belted direct to the mining-machinery. These motors are divided 

 into two groups ; two 20 horse-power Sprague motors and one 80 

 horse-power motor forming one group, and a single 20 horse-power 

 Sprague motor forming the other group. Each group is supplied 

 with current by a separate set of wires, thus practically insuring a 

 constant flow of electricity under all circumstances. 



The method of regulating the motors and keeping up a constant 

 speed in spite of the varying loads thrown on the mining-machinery 

 is accompHshed by winding the motors in a special way, so that 

 there is no mechanical governor to get out of order. The governor 

 being in the winding, and consequently acting without making any 

 movement, the motors are more durable, and the use of any com- 

 plicated mechanical governor is avoided. The motors are to run 

 on a constant potential circuit, and all the motors of each group 

 are connected together from positive to negative wires, thus equal- 

 izing the strain on the dynamos when the loads are thrown on the 

 motors. This method of connecting dynamos and motors is in 

 use in all Sprague stations for the transmission of power ; and it is 

 much superior in reliability and economy to the series method of 

 putting each motor on a separate connection. In principle it is the 

 same as supplying a city with water by running city mains instead 

 of using a separate conductor for each consumer. 



The question of efficiency, or the amount of the primal power 

 which is delivered at the farther end after the transmission, is one 

 which is very important. Upon this point electric transmission 

 compares very favorably with all other methods of transmitting 

 power. In this case the efficiency of the entire system, from the 

 turbine pulley to the mining-machines at the farther end, is about 

 70 per cent ; that is, 70 per cent of the energy which is delivered 

 from the turbine pulleys at the power-station is given off the motor 

 pulleys for work. 



New Electric Street-Railways. 



During the last week there have been a number of street-rail- 

 way companies which have contracted for electric-railway appa- 

 ratus in spite of the lateness of the season. The latest contracts 

 closed by the Sprague Electric Railway and Motor Company of 

 New York are for street-railways in Piqua, O., and South Nash- 

 ville, Tenn. 



The road at Piqua is an entirely new road, never having been 

 operated by any power before. The number of cars which will be 

 equipped will be four, and the line will extend for a few miles on 

 the main streets of Piqua. 



The South Nashville Street Railway Company will equip eight 



cars at present, but it is expected that the entire road will be run 

 by electric power before long. 



The Elliott Non-Electric Telephone. 



A PATENT was recently issued to Larkin V. Elliott of Moores- 

 town, Ind., for an improved form of mechanical or non-electric 

 telephone, which seems to possess several advantages over other 

 instruments of its class. The general appearance of this telephone 

 is shown in the accompanying illustration. The mouth-piece is 

 bell-shaped, and about four inches in diameter at its larger part, 

 the bore narrowing to about an inch and a quarter where it joins 

 the base. The aperture in the latter is cone-shaped, narrowing 

 from about four inches in diameter where it joins the mouth-piece 

 to half that size at the rear. Between the mouth-piece and the 

 base the diaphragm is securely fastened. The diaphragm consists 

 of two sheets of stretched rawhide, with an interposed layer of soft 

 fibrous material and a covering of some soft fabric. It is made in 

 the following manner. A sheet of thick rawhide is first stretched 

 tightly across the aperture in the base, preferably while wet, so 

 that when it dries it will be still more tightly drawn. Over this is 

 laid a layer of cotton batting or other soft fibrous material. Over 

 this a sheet of thin rawhide is stretched, but not as tightly as the 



first sheet. Lastly comes a sheet of velveteen. The whole is se- 

 cured firmly between the base and mouth-piece. 



The line-wire passes through an opening in the centre of the 

 diaphragm, being provided on its end with a button, which bears 

 against the velveteen surface of the diaphragm. The inventor 

 claims that this peculiar construction of the diaphragm, together 

 with the shapes of the apertures in the base and mouth-piece, not 

 only prevent the usual roaring sound in the receiver, but improve 

 the sound by rendering it more distinct, reproducing a clear, natu- 

 ral tone of voice, similar to that which acts upon the diaphragm at 

 the other end of the line-wire. 



The claims of the inventor in regard to the good qualities of 

 these telephones are borne out by the testimonials of many busi- 

 ness-men who have had them in use for several months. They are 

 intended only for short lines, from a few rods up to a couple of 

 miles. Proper suspension devices are provided, so that the line- 

 wire may be carried around angles without impairing the efficiency 

 of the instruments. An electric call-bell may be used in connection 

 with this telephone if desired. 



American Apparatus in Italy. 



Work on the electric-railway apparatus for the Florence and 

 Fiesole Road has been commenced upon at Schenectady, N.Y.,which 

 will be ready for shipment before long. This road will be operated 

 entirely by electric power, and Sprague electric cars will be used 

 throughout the entire line. 



The road connects the city of Florence with the city of Fiesole, 

 a distance of about five miles. The grades upon this line will be 

 very severe, sufficiently so to have precluded the use of horses upon 

 it. The regular Sprague system of overhead wires, using main 

 conductor with feeders, will be used. 



The fact that American railway apparatus have been adopted on 

 this line is extremely flattering to the company to whom the order 

 is given, and gratifying to the patriotism of every American. The 

 fact that the Sprague system was brought into direct competition, 

 in the matter of equipment of this road, with all the systems of 

 electric street-railways in Europe, shows in an additional way the 

 favorable reputation of American apparatus. 



