G20 SCIENTIFIC RECORD FOR 1833. 



Thus far it lias been applied only to the Jablochkoff candle. (Nature, 

 July, 1883, xxvin, 309.) 



Incandescent lighting is steadily working its way into public favor. 

 The Savoy theater, in London, has been lighted with 1,194 Swan lamps 

 for a year and a half with entire success. At the coronation in Moscow, 

 the tower of Ivan the Great, and its side galleries, were lighted with 

 3,500 Edison lamps. The Edison station in the first district of New 

 York City has run uninterruptedly since September, 1882, constantly 

 increasing the amount of light furnished. In December, 1883, 10,297 

 lamps were in use in that district, the bills rendered during Novem- 

 ber exceeding $10,000 for the month's lighting. The capacity of the 

 station has proved totally insufficient for the light required, and is 

 to be largely increased. Hence no electricity has yet been available 

 for power, notwithstanding the demand. At the Vienna Exhibition 

 various forms of incandescent lamps were exhibited, but none showing 

 marked improvement in durability. {Nature, March, 1883, xxvn, 418; 

 June, xxvin, 207 ; September, xxvin, 466 ; November, xxix, 42.) 



5. Electromagnetism. 



Wassmuth has experimented on the portative force of electromagnets, 

 using semicircular magnets in contact at their polar surfaces. He ob- 

 served that if a very thin sheet of mica be placed between the magnet 

 and its contact, provided the magnetization is not too strong, the por- 

 tative force increased from 4.7 to 9 kilograms. (J. Phys., April, 1883, 

 II, II, 193.) 



Ayrton and Perry have experimented to determine the effect of differ- 

 ent methods of winding upon the strength of electromagnets, the cur- 

 rent strength being constant. In the first case the wire was wound 

 uniformly over the entire length ; in the second it was " coned " toward 

 each end ; in the third it was wound uniformly over one half the bar 

 only; and in the fourth it was "coned" on one-half only. They con- 

 clude that with a definite iron core, a definite length of wire to be coiled 

 on it, and a definite current, the mode of coiling to produce the maxi- 

 mum field depends entirely on the distance from the end of the electro- 

 magnet at which this field is to be produced. With the magnet used, 

 they found that at distances very small compared with the length of 

 the core, the fourth method is best. When the field is to be produced 

 at a distance of one-third the length of the magnet, the third method 

 is preferable. While for distances equal to or greater than £ of the 

 length of the core the first method gives the best results. (Phil. Mag., 

 June, 1883, V, XV, 397.) 



At the Montreal meeting of the American Association Graham Bell 

 read a paper upon the electrical experiments made to determine the loca- 

 tion of the bullet in the body of the late President Garfield, and upon 

 a successful J'orm of inductiou balance for the painless detection of 

 metallic masses in the human body. (Proc. Am. Assoc. Adv. Scl, xxxi, 

 151 ; Am. J. ScL, January, 1883, III, xxv, 22.) 



