ABSTRACTS OF TECHNICAL ARTICLES 541 



to the surface; the hydrocarbon chains of barium stearate are found to 

 be more precisely oriented than those of stearic acid; exactly the same 

 difference exists between unrubbed single layers of molecules of barium 

 stearate and of stearic acid deposited by the Langmuir-Blodgett 

 method. Thickness of rubbed films on chromium has been found, by 

 the Blodgett optical method, to be the same as that of unrubbed 

 single layers of molecules. Lightly rubbed films may be thicker than a 

 single layer of molecules. The arrangement of barium stearate in such 

 thicker films has been found to have been somewhat altered by the 

 rubbing. The axes of the hydrocarbon chains still stand normal to the 

 surface, but lateral arrangement is less regular than it is in unrubbed 

 films of equal thickness. In the case of stearic acid, molecules left on 

 top of the first layer after light rubbing in one direction are found to lie 

 inclined by about 8° to the surface and to point outward against the 

 rubbing direction (Fig. 7) ; they are arranged in crystals having a 

 structure different from that of the film before rubbing. Such "up- 

 set" films of stearic acid are completely removed by very light rubbing 

 in the direction opposite to that of the original rubbing, but they are 

 rather resistant to light rubbing in the same direction. 



Diffraction and Refraction of a Horizontally Polarized Electromag- 

 netic Wave over a Spherical Earth.^ Marion C. Gray. Formulas are 

 derived for the electromagnetic field at a point on or above the surface 

 of a spherical earth due to the presence of a vertical magnetic dipole. 

 It is shown that the resultant field resembles that due to a vertical 

 electric dipole above a spherical earth of low conductivity, and that in 

 the magnetic case the values of the earth constants are of much less 

 importance than in the electric. Curves are included showing the 

 variation of the field with distance and with height. 



Inductive Coordination with Series Sodium Highway Lighting Cir- 

 cuits.^ H. E. Kent and P. W. Blye. This paper describes the wave- 

 shape characteristics of the sodium-vapor lamp and discusses the rela- 

 tive inductive influence of various series circuit arrangements in which 

 such lamps are employed. A method is outlined by means of which 

 the noise to be expected in an exposed telephone line may be estimated. 

 Measures are described which may be applied in the telephone plant or 

 in the lighting circuit to assist in the inductive coordination of the 

 two systems. These measures need be considered only when a con- 

 siderable number of lamps is involved, since noise induction is negli- 



8 Phil. Mag., April 1939. 



' Electrical Engineering, Transactions Section, July 1939. 



