September 14, 1900. ] 



SCIENCE. 



411 



units, and the Congress should be invited to 

 find ways and means to obtain such a rational- 

 ization. 



The proposition to rationalize the units — that 

 is, to change them so that the coefficient 4t 

 should not appear — was withdrawn by Dr. 

 Kennelly on behalf of the United States ; as 

 well as the suggestion regarding the employ- 

 ment of prefixes, and it was resolved that : 



The Commission will only deal with proposi- 

 tions that will introduce no change in the de- 

 cisions arrived at at previous congresses. 



A long discussion then took place as to 

 whether it was really necessary to give names 

 to the C. G. S. units either in the electrostatic or 

 the electromagnetic systems, and finally it was 

 agreed to withdraw the proposition so far as it 

 dealt with the electrostatic system. 



The desirability of giving a name to the unit 

 of magnetic field and to the unit magnetic flux 

 was strongly urged, and as the names of Gauss 

 and Weber had been employed for some years 

 in America for these units respectively, the ad- 

 vantage of adopting these names for the C. G. S. 

 units of field and flux was advocated. On the 

 other hand, the resolution arrived at by the 

 Electrical Standards Committee of the British 

 Association in 1895 to employ those names re- 

 spectively for other units was pointed out. 

 Finally, the Commission, at the eud of their 

 second sitting, on August 22d, recommended the 

 following : — 



" The Commission is not of opinion that it is 

 necessary to give names to all the electromag- 

 netic units. 



"However, in view of the use already of 

 practical instruments which give the strength 

 of a magnetic field directly to C. G. S. units, the 

 Commisiion recommends that the name of Gauss 

 be assigned to this unit in the C. G. S. system. 



' ' The Commission proposes to assign to the 

 unit of magnetic flux, of which the magnitude 

 will be subsequently defined, the name of Max- 

 well. ' ' 



These resolutions were brought before Sec- 

 tion I. of the Congress on August 24th, and 

 led to a long discussion. M. Mascart opposed 

 the giving a name to the C. G. S. unit of mag- 

 netic field. The employment of practical instru- 

 ments for the direct measurement of the strength 



of magnetic fields in C. G. S. units was not, in 

 his opinion, a sufficient reason for assigning a 

 name to that unit. Besides, this decision of the 

 Commission appeared to be contrary to the 

 spirit of the Congresses of 1881 and 1889, which 

 did not give the names of men to the C. G. S. 

 units. He admitted that the name of a man 

 might be given to the practical unit. In any 

 case the name of ' Gauss ' seemed to him liable 

 to give rise to confusion, for Gauss was the 

 originator of the first absolute system employed, 

 viz, that of the ' millimetre-milligramme-sec- 

 ond ' system, and that system, as distinguished 

 from the ' centimetre-gramme-second ' system, 

 was still in actual use in certain cases — for the 

 measurement of the earth's field, for example. 



Professor Kohli-ausch said that the ' absolute 

 units ' were enough for the physicists, but that, 

 if the engineers felt the need of practical units, 

 Dr. Dorn and he did not see that any incon- 

 venience would arise from names being given 

 to them, such as those of Gauss and of Max- 

 well, for example. The German delegates 

 could not, however, commit their Government 

 in the matter, and they considered that the 

 Congress should limit its recommendations to 

 the use of these new names without seeking 

 that legal sanction should be given to them. 



Professor Ayrton agreed with M. Mascart, 

 and mentioned that during the past five years 

 many ' Ayrton-Mather Field Testers ' had been 

 constructed to read ofi" the strength of a mag- 

 netic field directly in C. G. S. units, but that no 

 need for any special name for that unit had 

 been felt in connection therewith. He added, 

 however, that, while holding the opinion ex- 

 pressed by M. Mascart that it was not desirable 

 to give the names of persons to the C. G. S. 

 units, the units of field and flux had this 

 peculiarity, that without any multipliers they 

 were the practical units adopted. 



To this M. Mascart replied that the word 

 ' practical' in this connection was ambiguous, 

 since, although it was true that the C. G. S. units 

 of magnetic field and fiux were employed in 

 practice, they did not belong to the so-called 

 'practical system.' 



M. Hospitalier appealed to the Section to 

 give names to the unit of field and the unit of 

 flux. He did not ask for any legal decision in 



