SCIENCE. 



FRIDAY, JULY 11, 1884. 



COMMENT AND CRITICISM. 



The increasing number of international sci- 

 entific congresses whose function is the estab- 

 lishment of common points of departure, and 

 the unification of standards of measure both as 

 to dimensions and nomenclature, is a hopeful 

 sign of progress towards the ' millennium ' to 

 which men of science are unquestionably near- 

 er than their political brethren. It is delight- 

 ful to find that there are so many important 

 matters concerning which scientific men repre- 

 senting many nations and many languages find 

 themselves in perfect agreement. Although in 

 many instances a surrender of some personal 

 or patriotic claims has been demanded, this 

 has been generally acceded to with little pro- 

 test, to the end that universal advantage may 

 be the outcome. When work of this kind is 

 done, it should be done for all time to come ; 

 at least, what is definite!}' fixed upon should be 

 of such a nature that it will not need undoing 

 in the near future. 



In this respect the report of the electrical 

 congress is something of a disappointment. 

 The congress seems to have reached its con- 

 clusions in undue haste. Indeed, the electrical 

 units as now defined are less precise and sci- 

 entific than before. The reference of the prac- 

 tical units to those of the c. g. s. system was 

 in itself admirable and satisfactory. With 

 the new definitions, one only, that of current 

 strength, has a precise relation to the fun- 

 damental units : the others have become ar- 

 bitral Would it not have been better to 

 adhere to the original ohm, and to define the 

 mercury unit as provisional? The new mer- 

 cury unit is obtained from measurements that 

 differ among themselves by more than two per 

 cent. Besides, the verdict was made up before 

 the results of Professor Rowland's exhaustive 



No. 75.- 1884. 



investigation, now in process, were in the pos- 

 session of the congress, although this investi- 

 gation was admitted to be one of the most 

 important. A provisional mercuiy unit of a 

 hundred and six centimetres would have satis- 

 fied all practical demands, and would have been 

 subject to such correction as future research 

 indicated to be necessar}-. As the matter now 

 stands, the elegance and simplicity of the sys- 

 tem is destroyed by the introduction of arbi- 

 trary units, the value of which ma} r some time 

 be found to be considerably different from that 

 now assumed. 



While the congress might have acted more 

 wisely in the opinion of many, in the matter 

 of the ohm, in its definition of the standard 

 of light it would certainly have done well to 

 postpone action for the present. It appears, 

 that, because nothing better was offered, the 

 square centimetre of fused platinum was adopt- 

 ed. Although this is a matter which is great- 

 ly in need of adjustment, there can be little 

 satisfaction in the adoption of what is, as near- 

 ly as may be, an impossible standard. There 

 must have been a paucity of suggestions as to 

 a suitable standard ; which is singular, consid- 

 ering the prominence of the problem of meas- 

 uring intense lights. And in recommending 

 that all records of observations of atmospheric 

 electricity and earth-currents should be sent 

 to the international bureau at Berne, the con- 

 gress simply acknowledged our present igno- 

 rance. 



Bibliographies of special authors have but 

 an ephemeral value, if made during the life, or 

 at least during the activity, of a writer. It 

 would therefore, in our judgment, have been 

 better to restrict the one just issued by the 

 National museum, and fuUy described in our 

 notes, to Professor Baird's direct contributions 

 to science, which have avowedly ceased, and 



