952 



SCIENCE. 



[N. S. Vol. XII. No. 312. 



rent through it. He had noticed that the 

 kaolin he had placed between the carbons 

 of his arc lamp assisted the illumination. 



These inventions show something of the 

 development of knowledge regarding ma- 

 terials which might be made incandescent, 

 and the means taken to make them incan- 

 desce. 



Several years later, in 1881, W. M. Jack- 

 son (an American) invented the device of 

 a lamp made of platinum, iridium or other 

 materials non-osidizable at high tempera- 

 tures, in the form of wires of small section 

 which were heated to incandescence by the 

 use of a heating flame. He discovered that 

 the finer his wires, the more intense the 

 light produced. Here is a beginning of a 

 mantle light. 



In 1881, Charles M. Lungren, of New 

 York, patented in the U. S. Patent Ofiice 

 an improvement in illuminating apparatus, 

 which consisted in passing a non-luminous 

 gas flame through a heater of clay or 

 similar material highly heated by jets of 

 the non-luminous gas, and forcing atmos- 

 pheric air through the heater and causing 

 it to mingle with the non-luminous gas 

 issuing in one or more jet flames against 

 lime, magnesia, zirconia or similar material, 

 producing incandescence. 



In the same year (1881) Mr. Lungren 

 filed an application in the Patent Office for 

 a means of illumination which consisted in 

 forming a ^filamentary body of refractory 

 material, said body having the structural 

 form necessary to envelope a gas flame and 

 to be rendered incandescent by such flame. 



This application, after allowance by the 

 Patent Oifice, was permitted to lapse, and 

 no patent was then issued. 



Mr.- Lungren, however, renewed his ap- 

 plication in August, 1885, and the patent, 

 which embodied improvements upon his 

 unissued patent of 1881, was issued July 5, 

 1887 (No. 365,832). Subsequently, a sec- 

 ond patent (No. 367,534), describing spe- 



cific features of his incandescent lighting 

 method, was issued to Lungren under date 

 of August 2, 1887. 



In the first of these patents Lungren de- 

 scribes his method of making refractory 

 filaments for Ughting composed of ' lime, 

 magnesia, zirconia, etc.,' by preparing a 

 plastic mass of these materials, or mixtures 

 of them by kneading them with water, or 

 preferably, a solution of a mucilaginous 

 binding material, such as glue or gum, or 

 other combustible matei'ial which will be 

 consumed in the further treatment of the 

 filament. When the mass is of the proper 

 consistence, it is put in a press and the 

 filament is obtained by expressing the ma- 

 terial through a die. Immediately after 

 their formation, and while still moist, the 

 filaments are formed up into various shapes 

 desired by bending or coiling over a man- 

 drel of wood coated Math plumbago, or 

 other device, and then dried, when they are 

 ready to apply to a support and to be used 

 in connection with a gas flame, in substan- 

 tially the same manner as the well-known 

 Welsbach mantle. 



The Lungren incandescent lighting sys- 

 tem was the subject of investigation by the 

 Committee on Science and the Arts of the 

 Franklin Institute in 1891. Prolonged 

 practical tests of the Lungren filaments 

 showed that they possessed unusual life 

 duration in service, with satisfactory light- 

 ing quality ; and the award of the John 

 Scott Legacy Premium and Medal was made 

 to the inventor. 



For reasons unknown to your committee, 

 this promising invention was never com- 

 mercially exploited. 



The next year (1882) a Frenchman, 

 Charles Clamond, invented a lime Ught 

 operated without oxyhydrogen flame by in- 

 tensely heating the air used and directing 

 the flame of his air and gas mixture against 

 the refractory oxide chosen. He knew of 

 the possible use of certain other metallic 



