520 



MECHANICAL IMPKOVEMENTS AND INVENTIONS. 



utes, with only 4 gallons of water in the boiler. 

 The apparatus consisted of a mirror so curved 

 as to have a linear focus, a blackened boiler, 

 and a glass envelope about the whole, admit- 

 ting the rays of light, but preventing the re- 

 turn of the heat-rays. It is not pretended that 

 the effect is powerful enough to originate suffi- 

 cient mechanical power for practical purposes 

 in the temperate zone, but the inventor is 

 firmly persuaded that in hot climates a motor 

 might be constructed which could be impelled 

 by the direct action of the solar heat. 



The practical employment of the electric 

 light in the illumination of large factories has 

 been introduced in France, and is constantly 

 growing in favor. Even on the score of cheap- 

 ness, where a large space is to be illuminated, 

 this method seems to have the advantage over 

 the other kinds of artificial light. But it has 

 other points of superiority, more important 

 than that of economy: the mechanics can per- 

 form their labors by this light as rapidly and 

 easily as in daylight, which no other illumina- 

 tion allows ; the danger of fire is entirely 

 avoided ; no blackening of the walls and ceil- 

 ings takes plaee ; and the property possessed 

 by the magnetic light of reflecting the true 

 colors of objects gives it a specially important 

 advantage in some manufacturing processes. 

 The electro-magnetic apparatus of Gramme is 

 employed for generating the light ; and a regu- 

 lator manufactured by Serrin is the one gen- 

 erally used. The carbonic substance used for 

 the production of the voltaic currents is the 

 plumbago-like incrustations which form in gas- 

 retorts. Several such instruments can be put 

 up in a few hours' time ; and in two or three 

 days a laborer can learn how to manage the 

 lamps and the machine. No part of the machine 

 can become deranged. Most establishments 

 possess the motive power needed to operate 

 the generating machine ; a motive power of 

 200 kilometres is required to start the opera- 

 tion. Calculations of the cost of the electro- 

 magnetic light prove that a light equal to 

 that of 400 carcel-lamps of ordinary size (equal 

 to the light of 7 times the number of stearine 

 candles, or to that of an equal number of 

 ordinary gas-burners) can be produced at an 

 expense of about 16 cents per hour, while 

 the same degree of illumination could not be 

 famished by gas, according to Paris prices, 

 at less than 14 times that cost. When only 

 100 gas-burners are used in a factory the ex- 

 pense is 3J- times greater than that of elec- 

 tric lights of 4 times the illuminating pow- 

 er ; while the apparatus required for gas- 

 lighting is much more costly than that needed 

 for this process. The carbonic substance em- 

 ployed in generating this light will probably be 

 more cheaply produced in a short time, or will 

 give place to some cheaper substitute. Before 

 the beginning of this year only two such ap- 

 paratus were in operation, one in the foundery 

 of Ducommun & Co. in Mulhouse. and one in 

 Gramme's workshop in Paris. Within the last 



year the machine has been erected in many 

 extensive factories in France, Eussia, Spain, 

 England, Austria, Italy, and in South Amer- 

 ica. This light is employed in the station of 

 the Northern Eailroad at Paris; and upon 

 ships in the French, Russian, and Austrian 

 marine ; and one of them was used on the 

 Polaris in the late Polar Expedition. In the 

 foundery at Mulhouse a room, 56 by 28 metres, 

 is lighted by 4 Serrin lamps, so well that no 

 shadows are cast, and in every spot of the in- 

 terior one can see to read as easily as by day- 

 light. This establishment has used this process 

 for two years ; the outlay of capital was 12,000 

 francs, and the expense of illumination 3 francs 

 per hour, including interest. In the weaving- 

 establishment of Pouyer-Quertier, at L'lle- 

 Dieu, in France, a room having a surface to 

 be illuminated of 600 square metres, in which 

 140 looms are operated, is lighted by 4 of 

 Gramme's machines with 100 burners and 8 

 lamps, so adjusted that the light comes from 

 below, and is reflected from the ceiling, and 

 the sources are concealed from the operatives. 

 In the Sautter-Lemonnier factory of light- 

 house lamps, at Paris, 3 Gramme machines are 

 employed in the mounting-shop and copper 

 smithy, with 100 burners and 3 lamps. The 

 lamps are constructed upon three different 

 systems: that of Serrin, that of Carre, and 

 that of Duboscq ; the one of Serrin's con- 

 struction is found to be the most reliable and 

 efficient. The surface to be lighted is 1,200 

 square metres. A large number of machines of 

 different uses are scattered about the room, but 

 by means of cross-lights all interfering shadows 

 are avoided. The light is quite sufficient for 

 all the different mechanical operations here 

 carried on. In the harbor at Salmaize boats 

 carrying beets for the sugar-factory are un- 

 loaded in the evening by the employment of 

 the magnetic light as well as by day. 



A Russian man of science, M. Jablouskoff, 

 has made an invention by which the electric 

 light can be distributed, and a single current 

 may be divided among several electric burners, 

 though separated from each other by consider- 

 able distances. The light produced" is greater 

 in volume than by the old method, and the 

 regulators, which have been the most expen- 

 sive and least durable part of the apparatus, 

 are done away with entirely. His process is 

 to inclose two pencils of carbon, parallel to 

 each other and adjusted at the right distance 

 apart, so that when inverted the current passes 

 from the end of one to the end of the other, 

 in a single cylinder of clay, powdered stone, 

 or the like. Any number of these may be 

 connected with a single battery. As the com- 

 bustion goes on, the envelope is also consumed, 

 adding to the light. The pencils always re- 

 mai-n parallel, and at the same distance apart, 

 so that the use of a regulator is dispensed 

 with. 



An American electrician, Mr. W. E. Sawyer, 

 has invented a method of telegraphy by which 



