ASSOCIATIONS FOR ADVANCEMENT ol- 1 SILENCE. (AMERICAN.) 



niinations of atomic weights was published, he 

 pronounced the hypothesis a pure illusion, irrecon- 

 cilable with the numerical results of experiment. 

 But Mallet, who has made several excellent deter- 

 minations of atomic weights, and Clarke, who has 

 recomputed and reduced to order all the published 

 determinations, declared themselves forced to give 

 I 'rout's hypothesis a most respectful considera- 

 tion. 



" Since our last meeting in this city results have 

 been attained which show that further effort in- this 

 direction is not justified by the hope of any theo- 

 retic advantage. Prout's hypothesis can not be 

 proved by experiment. In the first place, we can 

 more readily test the correctness of Prout's hy- 

 pothesis by determinations of the smaller atomic 

 weights. Among the smaller atomic weights some 

 can be more accurately determined than others. 

 Accordingly, a second condition imposed on us by 

 the limitations of our knowledge is that we must 

 determine with what precision we can those small 

 atomic weights which admit of the maximum of 

 precision. The third condition imposed on us, in 

 attempting to learn the truth about Prout's hy- 

 pothesis, is that the atomic weight of oxygen must 

 be well determined. 



" Since that time [1876] 11 independent determi- 

 nations of the atomic weights of oxygen have been 

 successfully concluded. One of these differs much 

 from the mean of all the others. The other 10 are 

 concordant. They differ on the average only 1 

 part in 2,200 from their mean, and the greatest dif- 

 ference from the mean is about 1 part in 1,000. 

 We may then fairly assume that the system- 

 atic error of the mean is less than 1 part in 1,000. 

 It has been found possible to weigh some hydrogen, 

 to weigh the requisite oxygen, and to weigh the 

 water they produce. If there were some unde- 

 tected systematic error in weighing either one of 

 these 3 substances, occasioned, for instance, by 

 some undetected impurity, the sum of the weights 

 of the hydrogen and oxygen would differ from the 

 weight of the water produced. The net results of 

 the experiments made in Denmark, Prance, Great 

 Britain, and the United States is that the atomic 

 weight of oxygen is between 15'87 and 15'89, and 

 that probably it is between 15'875 and 15'885. By 

 no stretch can we imagine that the truth lies in the 

 whole number 16 or in the even fraction 15'50. 



" I have argued that Prout's hypothesis is not 

 true as heretofore enunciated, and that if some 

 further modification of it is true we can not know 

 it. This conclusion has been sustained by the evi- 

 dence of the chemist's balance. A conclusion sup- 

 ported by a single kind of evidence may command 

 the confidence of one who has been long familiar 

 with the evidence and who has become capable of 

 weighing it : but for others the concurrence, of evi- 

 dence of different kinds adds greatly to the cogency. 

 In this case there is such concurrent evidence. 

 Since Prout's hypothesis lias rendered us its final 

 service new hypotheses must be devised." 



Proceedings of the Sections. The association 

 is divided into 9 sections, each of which is presided 

 over by an officer having the rank of vice-president 

 of the association. Subsequent to the opening pro- 

 ceedings each section meets by itself and effects its 

 organization by electing a fellow to represent it in 

 the council, a sectional committee of 3 fellows, a 

 fellow or member to the nominating committee, 

 and a committee of 3 members or fellows -to nomi- 

 nate officers of the section for the next meeting. 

 As soon as this organization is effected, the secre- 

 tary of the section reports to the general secretary. 

 who then provides him with a list of papers that, 

 having been considered suitable by the council, 

 may be read and discussed before the section. On 



the first day the proceedings are usually confined to 

 organization and the delivery of the inaugural or 

 vice-presidential addresses. 



A. Mathematics. At the meeting held last year, 

 William E. Story, of Worcester. Mass., was chosen 

 vice-president for this section, but lie was unable to 

 attend the meeting, and therefore no address was 

 delivered. The vacancy was filled by Alexander 

 Macfarlane, of South Bethlehem, Pa. 



The following-named papers were read and dis- 

 cussed before the section : " An Analogue to De- 

 .Moivre's Theorem in a Plane Point System," by 

 Edward W. Hyde: Rational Scalene Triangles," 

 by Artemas Martin; "New Elements of the Varia- 

 ble It Coma?, resulting from Observations in July 

 and August, 18%." and " Photometric Observations 

 of Colored Stars," by Henry M. Parkhurst ; "Mo- 

 tion of the Great Red Spot and Equatorial Belt of 

 the Planet Jupiter from 1879 to 1896." by George 

 W. Hough; "On the Direct Application of a Ra- 

 tional Differential Equation to a Series of Points 

 whose Co-ordinates represent Observed Physical 

 Properties," by Robert B. Warder; "A Proposed 

 Fundamental Integral-Transcendent," by James 

 McMahon; "On the Level of Sun Spois." by Edwin 

 I!. Frost: " Sedonians,'' by James B. Shaw; "On 

 the Distribution and the Secular Variation of Ter- 

 restrial Magnetism, No. IV: On the Component 

 Fields of the Earth's Magnetism," by Louis A. 

 Bauer; "Determination of Weights of Observa- 

 tions." by John K. Eastman; and "On the Compo- 

 sition of Simultaneous and Successive Vectors," by 

 Alexander Macfarlane. 



B. Pit y.s/c-s. The presiding officer of this section 

 was Carl L. Mees, President of Rose Polytechnic 

 Institute, in Terre Haute, Ind. He chose as the 

 subject of his address " Electrolysis and some Out- 

 standing Problems in Molecular Dynamics." 



This address was a historical review from the be- 

 ginning of the observation of electrolytic action, 

 about the middle of the eighteenth century, through 

 its development to the present day. The several 

 theories explaining the action within the electro- 

 lyte when chemical decomposition occurs, from 

 Grothuss's hypothesis to Arrhenius's theory, were 

 critically discussed and analyzed. The relations 

 between osmotic pressure, solution modification of 

 vapor tension, and the freezing point were traced 

 and discussed, showing that the evidence in favor 

 of similarity of dynamical action was very great. 

 Nernst and Ostwald's applications of these princi- 

 ples to the cause of electro-motive force in batteries 

 were examined and briefly discussed, together with 

 the application of thermodynamic principles to the 

 problem. The difficulty of obtaining reliable ex- 

 perimental data for the final testing of these the- 

 ories was pointed out. together with the suggestion 

 of lines of investigation to be pursued in their 

 further development. Attention was called to the 

 fact that these studies had been neglected to a 

 great extent by physicists, having been mainly car- 

 ried on by chemists, and thus many fruitful esscn- 

 tially physical concepts of molecular actions and 

 relations have been neglected. Especially is this 

 true of American physicists, by whom, with the ex- 

 ception of Willard Bibbs, scarcely a contribution 

 has been made until within I lie past year. Ameri- 

 can workers were urged to attack some of the im- 

 portant problems suggested. The necessary modi- 

 fication of conceptions as to atomic and molecular 

 relations now held if this theory were accepted was 

 referred to, as well as some necessary modifications 

 of these theories in case electrolytic action may 

 take place in solids and gases, such as alloy and 

 glasses, the probability of such action being shown 

 by a brief discussion of some of their electrical 

 properties. The address closed with a brief sum- 



