Gvlick — Divergent Efoohttion and the Darioinian Theory. 21 



tricity, especially the electric car system, lias led to great dis- 

 turbances in the telephone circuits. These disturbances are 

 due both to leakage from the power circuit into the telephone 



circuit, since the earth is used partially by the electric power 

 companies in their return circuits, and to actual induction. 

 The best remedy for these disturbances is doubtless the adop- 

 tion by either the power companies or the telephone companies 

 entire metallic circuits, in which the earth plays no part. 

 If this is not possible, a system of neutralization for the induc- 

 tive disturbances might be adopted as follows. Let a shunt 

 circuit from the electric light wire or the wire carrying the 

 current for motors be led into a station through which also 

 passes the telephone wire. The resistance of this shunt or de- 

 rived circuit can be made suitable for the purpose. In all 

 case> it reduces the resistance of the main line, and is therefore 

 not prejudicial. On this shunt can be arranged a fixed coil, 

 and on a neighboring telephone wire a movable coil of no self- 

 induction. Let this movable coil be placed in front of the 

 fixed coil in the motor circuit, and let it be turned until the 

 mutual induction between it and the fixed coil neutralizes the 

 induction produced at all points along the telephone circuit. 

 Each telephone wire would need its movable coil, and to every 

 movable coil would correspond a fixed coil in the shunt of the 

 motor circuit. The operator at the central station could adjust 

 the movable coils until the disturbances arising from induction 

 at various points along the line are neutralized. 



Art. III. — Divergent Evolution and the Darwinian Theory ; 

 by Rev. John T. Gulick, Ph.D. 



In a paper on Divergent Evolution through Cumulative 

 Segregation (Linnean Soc. Journal. Zoology, vol xx, pp. 189— 

 274), I have endeavored to show that selection, whether natural 

 or artificial, is a process that has no tendency to produce diver- 

 gent evolution, unless different sections of one original stock 

 are subjected to different forms of selection, while at the same 

 time some cause prevents free crossing between the different 

 sections. We now inquire whether Darwin has made us 

 acquainted with any cause or combination of causes that, with- 

 out the aid of man, produces diversity of selection and at the 

 same time the independent generation of the different classes 

 of variations thus preserved. 



Darwin discusses the causes of natural selection more fully 

 than the causes of diversity of natural selection. lie does not 



