February 17, 1905.] 



SCIENCE. 



25H 



January number of the Journal of the 

 Chemical Society, page 62. 



F. W. Clarke, as a member of the Inter- 

 national Committee on Atomic Weights, 

 and of the corresponding committee of the 

 society, gave an account of the changes 

 made in the atomic weights during the 

 year. The report of the International 

 Committee is published in the January 

 number of the Journal of the society. It 

 was discussed by W. A. Noyes, W. D. Ban- 

 croft, A. A. Noyes and R. C. Wells. 



At the afternoon meeting, the address of 

 Wilder D. Bancroft, the retiring vice-presi- 

 dent of Section C, on 'Future Develop- 

 ments of Physical Chemistry, ' Avas listened 

 to with great interest. It was published in 

 Science, January 13, page 50. 



On Thursday morning there was another 

 general meeting of the society, at which the 

 following papers were read : 



The Atomic Weights of Sodium and 

 Chlorine: Theodore W. Richards and 

 R. C. Wells. 



Very careful analyses and syntheses of 

 sodium and silver chlorides, made with 

 purest materials from many sources, were 

 made by several methods. These furnished 

 convincing evidence of weighable traces of 

 impurity in Stas's silver, and minor errors 

 in his methods of work. Many observa- 

 tions were made which must be considered 

 in any investigation of the highest ac- 

 curacy, concerning the occlusion of im- 

 purities by precipitates, and the solubility 

 of precipitates. Nearly a hundred quanti- 

 tative experiments were made, and of these 

 thirty ranked as final determinations. The 

 result for the atomic Aveight of sodium was 

 23.008, and for the atomic weight of 

 chlorine 35.473, if silver is taken as 

 107.930 ; hxit evidence was obtained show- 

 ing that this value for silver is slightly 

 too large. Further investigations, con- 

 nected with and suggested by this work are 

 in progress. The authors are greatly in- 



debted to the Carnegie Institution of Wash- 

 ington for pecuniary assistance. 



The paper will be published in the 'Pub- 

 lications of the Carnegie Institution of 

 Washington' and also in the Journal of the 

 American Chemical Society. 



The Present Condition of Analytical Chem- 

 istry : W. F. Hillebrand. 

 The author refers to the evidence that 

 has accumulated during the past years, 

 .showing a condition in technical analysis 

 in this country which calls for the earnest 

 attention of chemists, and particularly of 

 instructors of chemistry. An opinion 

 seems to be gaining ground that faulty in- 

 struction is at the bottom of much of the 

 trouble. This view the author is forced 

 to regard as not unfounded, though he 

 thinks the faults are more commonly those 

 of omission than of commission. He re- 

 gards it as of the greatest importance that 

 students should be made to think at every 

 step of what they are doing and why they 

 are doing it, that they should be made to 

 test their distilled water and reagents as 

 a matter of course, both as to quality and 

 quantity of contamination, so as to have 

 definite knowledge regarding the magni- 

 tude of the errors in their work ascribable 

 to these impurities; that they should be 

 obliged to check the accuracy of their work 

 by analyzing some fairly complex material 

 like a limestone, cement or slag, the exact 

 composition of which has been carefully 

 ascertained. The committee on uniformity 

 in technical analysis of the American 

 Chemical Society will soon be ready to send 

 to all applicants a standard limestone of 

 known composition, so that instructors 

 may test their own or their students' skill 

 as analysts, and employers that of their 

 employees. No good work can be done un- 

 less the workman has good tools and knows 

 how, when and why to use them. Full 

 recognition is given of the adverse condi- 

 tions confronting many, if not most, chem- 



