738 



SCIENCE. 



[N. S. Vol. V. No. 123. 



the atom must have volume if it has mass, and 

 that equal elementary masses imply equal vol- 

 umes ; ■when he attempts to disprove the possi- 

 bility of a vortex atom in a homegeneous fluid; 

 when he tries to prove the conception of atoms 

 as centers of force inconsistent with the idea of 

 mass ; and in many details of his argument. 



With greater success he exhibits the incon- 

 sistency and incompleteness of molecular theory 

 in chemistry ; shows the inadequacy of the 

 hypothesis of a single ether or a multitude of 

 ethers to explain action at a distance ; of the 

 hypothesis — ' that scandal of atomistics ' — of 

 molecular atmospheres to explain attraction 

 and repulsion ; and, in general, of any hypothe- 

 sis of an indivisible element to explain elasticity 

 and other properties of matter. He compels us 

 to see that our analysis only draws out of the 

 atom what we have put into it ; that, indeed, 

 the atom of modern physics is a little world, 

 almost organized, upon which are assembled all 

 the properties and dynamic relations which it 

 was to have been their mission to explain. 



E. A. Strong. 



Ypsilanti, Mich. 



SCIENTIFIC JOURNALS. 

 THE AMERICAN JOURNAL OP SCIENCE. 



The leading article of the May number is a 

 biographical paper about the late Professor 

 Hubert A. Newton, by J. W. Gibbs. It presents 

 a brief account of his life and estimate of his 

 personal character, and besides gives an ex- 

 tended and thorough summary of his contribu- 

 tions to astronomical science. This paper was 

 read before the National Academy of Sciences 

 at the recent meeting in Washington. 



A. G. Webster discusses a method of pro- 

 ducing constant angular velocity in cases where 

 a considerable amount of power is needed, as 

 in driving a large telescope or siderostat. It is 

 based upon the use of a tuning fork which in- 

 terrupts an intermittent current and thus regu- 

 lates an electric motor. Some experiments 

 show that the method is a practical one up to 

 more than one and a-half horse power. The 

 same author also discusses a method for rapidly 

 breaking powerful electrical currents. The end 

 is accomplished by making the break under 

 water while the mercury surface employed is 



kept clean by being continuously elevated by 

 means of an aspirated pump. By this means 

 the jet is kept cool and presents a continually 

 fresh surface of mercury, this being washed by 

 the flowing water. The apparatus was found 

 satisfactory in a current of twelve mean 

 amperes carried on for the course of an hour. 



John Trowbridge, following out the line of 

 discussion involved in the paper in the April 

 number, discusses the ' Electrical Conductivity 

 of the Ether.' By the method employed the 

 author thinks he obtains an estimate of the 

 energy required to produce the Rontgen rays 

 and also a measure of resistance of sparks in 

 air and different media. He closes thus : "It 

 shows conclusively that the discharge in a 

 Crookes tube at the instant when the Rontgen 

 rays are being emitted most intensely is an 

 oscillatory discharge. In popular language it 

 can be maintained that a discharge of lightning 

 a mile long under certain conditions encounters 

 no more resistance during its oscillations than 

 one of a foot in length. In other words, Ohm's 

 law does not hold for electric sparks in air or 

 gases. Disruptive discharges in gases and in 

 air appear to be of the nature of voltaic arcs. 

 Each oscillation can be considered as forming 

 an are. It is well known that a minute spark 

 precedes the formation of the voltaic arc in air. 

 The medium is first broken down and then the 

 arc follows. I believe that this process occurs 

 also in a vacuum and that absolute contact is 

 not necessary to start the arc. My experiments 

 lead me to conclude that under very high 

 electrical .stress the ether breaks down and be- 

 comes a good conductor." 



T. W. Richards and John Trowbridge discuss 

 the effect of great current strength on the con- 

 ductivity of electrolytes. Experiments were 

 made with copper sulphate and zinc sulphate, 

 and the conclusion is reached that the conduc- 

 tivity is not essentially affected by great changes 

 in the strength of the current. 



H. S. Williams has a paper on the Southern 

 Devonian formations, especially in southern 

 Virginia, Tennessee and Kentucky, where he 

 has recently carried on personal observations. 

 He shows the remarkable contrast which exists 

 between the formation as known in New York 

 State and that as developed in the South, where 



