September 1, 1911] 



SCIENCE 



283 



Papers which contain photographic evidence 

 that seems conclusive and which leads to the 

 above conclusions have been recently pub- 

 lished by the Academy of Science of St. Louis. 

 They give a rational explanation of older phe- 

 nomena which had not been explained on the 

 two-fluid theory. For example, why are posi- 

 tive and negative Lichtenberg figures so dif- 

 ferent in form? How are we to explain the 

 arc-like form of discharges, shorter than the 

 critical spark length? "What is the critical 

 spark length? An additional suggestion may 

 be made. 



Assume two spheres of mass m and m'. 

 They attract each other with a force Kmm'/r. 

 Assume that the spheres are connected by 

 means of a flexible conductor, and that nega- 

 tive corpuscles are pumped out of, or forced 

 into the two masses. A condition will be 

 found for which the attraction between these 

 two masses will be a maximum. If the num- 

 ber of corpuscles in the masses be then either 

 increased or diminished, the attraction will be 

 less. With small masses we can easily reduce 

 the attraction to zero, or make it negative. 



Why should we continue to say that in one 

 of these cases we are adding positive elec- 

 tricity to these spheres, when we are all fully 

 convinced that we are not? 



The attraction in dynes between these 

 masses of radii R and R' em., and distant 

 from each other r cm., the matter composing 

 them having a density p is 



^ = :^ {3J^iryKEB — V). 

 r 



This force will be zero when 



y= i'^P VKEB', 



where Y is potential in electrostatic units. 

 This last condition does not depend upon the 

 distance of these bodies from each other (neg- 

 lecting mutual induction), but upon the mag- 

 nitude of the bodies. 



For two bodies having the size of the moon 

 and earth, assuming that they have a density 

 p = 5.5, the potential must be raised to 1.96 X 

 10" volts, in order that they shall cease to at- 

 tract each other. 



The last equation may also be written 

 Kp-MM' = 9 o-ff', 



where a and o-' are surface densities on the 

 two bodies. 



The interesting suggestions of Arrhenius in 

 regard to the invasion of our atmosphere by 

 corpuscular radiation, suggest that the actual 

 potential of earth and moon are not widely 

 diflierent. While these considerations are per- 

 haps of no astronomical significance, they 

 nevertheless lead us towards a general conclu- 

 sion which seems to have some interest. 



May we not conclude that Newton's equa- 

 tion for gravitational attraction represents a 

 special case, in which all of the molecules in 

 both masses possess what might be called the 

 normal number of corpuscles? 



If one mass is in normal condition and the 

 other is " charged " as above, Newton's equa- 

 tion also represents a special case, the discus- 

 sion for which is apparent. 



Francis E. Nipher 



TSE AMERICAN CSEMICAL SOCIETY. IV 



DIVISION OF PHYSICAL AND INORGANIC CHEMISTRY 



H. P. Talbot, chairman 

 S. L. Bigelow, secretary 



The Mechanism of Meversible Oxidation and Se- 

 duction Reactions in Solutions: E. P. ScHOCH. 



Electrolytic Formation of Aniline without a Dia- 

 phragm: E. P. Parnau. 



Electrolytic Corrosion of some Metals: G. E. 

 White. 



The Vapor Density of Formic Acid as Affected iy 

 Changes of Temperature and Pressure: Alan 

 W. C. Menzies and Paul N. Leech. 



The Thermal Expansion of Solid Lithium and its 

 Change of Volume on Fusion: Alan W. C. 

 Menzies and B. K. Bsodie. 



The Liquidus Surface for the Ternary System 

 Composed of the Nitrates of Potassium, Sodium 

 and Calcium: Alan "W. C. Menzies and N. N. 



DUTT. 



The Free Energy of Dilution of Hydrochloric 

 Acid: E. C. Tolman and A. L. Ferguson. 

 A method is described of determining the free 

 energy of dilution of an electrolyte without em- 

 ploying cells that have liquid boundaries. Values 

 of the free energy of dilution of hydrochloric acid 



