DeckmbkeQI, 1900.] 



SCIENCE. 



951 



' Notes on the Spring Migration (1900) at Scarbor- 

 ough, N. Y.': Louis Agassiz Fueetes. 



'Impressions of Some Hawaiian Birds': H. W. 

 Henshaw. 



'A Visit to the Birthplace of Audubon ' : O. WlD- 



MANN. 



'Natural History of the Alaska Coast.' Illustra- 

 ted by lantern slides : C. Hart Mebeiam. 



' Notes on a Nest of Massachusetts Brown Creepers.' 

 Illustrated by lantern slides : A. P. Chadboubnb. 



' Bird Studies with a Camera. ' Illustrated by lan- 

 tern slides : Fbank M. Chapman. 



'Aptoschromatism.' A reply to Drs. Dwight and 

 Allen : Francis J. Birtwell. 



' On the Breeding Habits of Leconte's Sparrow ' : 

 P. B. Peabody. 



' On the Value of Careful Observations of Birds' 

 Habits ' : Edward H. Forbush. 



' Breeding of the Cerulean Warbler near Baltimore' : 

 Frank C. Kirkwood. 



' The Enforcement of the Lacey Act ' : T. S. 

 Palmer. 



The next annual meeting will be held at 

 the American Museum of ISTatural History, 

 New York City, commencing November 

 11, 1901. 



John H. Sage, 



Secretary. 



THE WELSBACH LIGHT.* 

 The Franklin Institute of the State of 

 Pennsylvania for the Promotion of the Me- 

 chanic Arts, acting through its Committee 

 on Science and the Arts, investigating the 

 merits of the Welsbach Light, which was 

 referred to the Committee by the Jury of 

 Awards of the late National Export Expo- 

 sition, 1899, reports as follows : 



The procuring of artificial light by some 

 means other than using the flame of burn- 

 ing carbonaceous material in the ordinary 

 candle, lamp or gas burner has been the 

 aim of many investigators. As a result of 

 this endeavor, we find on the one hand 

 * Being the report of the Franklin Institute, 

 through its Committee on Science and the Arts, on 

 the exhibit of the Welsbach Light Company, of Glou- 

 cester City, N. J., referred by the Bureau of Awards 

 of the National Export Exposition. Sub-Committee. 

 — Arthur J. Eowland, Chairman ; C. A. Hexamer, 

 Wm. McDevitt, Frank P. Brown, Moses G. Wilder. 



lamps in which carbon is heated to a point 

 where it gives off light — or becomes incan- 

 descent — as by the passage of an electric 

 current through an incandescent filament 

 or arc lamp crater ; or, on the other hand, 

 lamps in which the incandescence of certain 

 substances (oxides of certain of the elements 

 for the most part) is produced by the ap- 

 plication of a heating flame or the passage 

 of an electric current to raise their tem- 

 perature. Of these latter burners, the de- 

 velopment of those using a heating flame 

 applied to produce incandescence of rare 

 earths is the particular thing dealt with in 

 this report, but it seems impossible to avoid 

 a mention of others when giving an outline 

 of the chain of discoveries and inventions 

 leading up to the "Welsbach light of to-day. 



It is probable that Drummond is one of 

 the earliest discoverers of the fact that 

 heated oxides of certain elements incan- 

 desce. Certainly he made the first practical 

 application of the fact. Every one knows 

 of the Drummond or lime-light which has 

 been so commonly used in the projection 

 lantern. A piece of lime, or better, a piece 

 of oxide of magnesium, or, most refractory 

 of all, a piece of oxide of zirconium, has an 

 oxyhydrogen flame play upon it and is 

 thereby heated to a temperature at which 

 it incandesces and gives off an intensely- 

 bright white light. Lieutenant Thomas 

 Drummond, in the English government ser- 

 vice, made this discovery in 1826, and used 

 it in connection with his heliostat in sur- 

 veying work, and afterwards proposed the 

 same arrangement for lighthouse service. 



In 1868, Le Eoux, Professor at the Ecole 

 Polytechnique, Paris, discovered that a 

 brilliant incandescent light might be pro- 

 cured from a rod of lime or magnesia, by 

 heating it until an electric current passes, 

 this afterward maintaining the light. 



In 1879, Jablochkoff patented the use of 

 a piece of kaolin as a source of light, mak- 

 ing it incandesce by passing an electric cur- 



